Squashed 'external/libwebp/libwebp/' content from commit dd7364c3c

git-subtree-dir: external/libwebp/libwebp
git-subtree-split: dd7364c3cefe0f5c0b3c18c3b1887d353f90fc1f

.cmake-format.py

@@ -0,0 +1,240 @@
+# ----------------------------------
+# Options affecting listfile parsing
+# ----------------------------------
+with section("parse"):
+
+  # Specify structure for custom cmake functions
+  additional_commands = { 'foo': { 'flags': ['BAR', 'BAZ'],
+             'kwargs': {'DEPENDS': '*', 'HEADERS': '*', 'SOURCES': '*'}}}
+
+  # Override configurations per-command where available
+  override_spec = {}
+
+  # Specify variable tags.
+  vartags = []
+
+  # Specify property tags.
+  proptags = []
+
+# -----------------------------
+# Options affecting formatting.
+# -----------------------------
+with section("format"):
+
+  # Disable formatting entirely, making cmake-format a no-op
+  disable = False
+
+  # How wide to allow formatted cmake files
+  line_width = 80
+
+  # How many spaces to tab for indent
+  tab_size = 2
+
+  # If true, lines are indented using tab characters (utf-8 0x09) instead of
+  # <tab_size> space characters (utf-8 0x20). In cases where the layout would
+  # require a fractional tab character, the behavior of the  fractional
+  # indentation is governed by <fractional_tab_policy>
+  use_tabchars = False
+
+  # If <use_tabchars> is True, then the value of this variable indicates how
+  # fractional indentions are handled during whitespace replacement. If set to
+  # 'use-space', fractional indentation is left as spaces (utf-8 0x20). If set
+  # to `round-up` fractional indentation is replaced with a single tab character
+  # (utf-8 0x09) effectively shifting the column to the next tabstop
+  fractional_tab_policy = 'use-space'
+
+  # If an argument group contains more than this many sub-groups (parg or kwarg
+  # groups) then force it to a vertical layout.
+  max_subgroups_hwrap = 3
+
+  # If a positional argument group contains more than this many arguments, then
+  # force it to a vertical layout.
+  max_pargs_hwrap = 6
+
+  # If a cmdline positional group consumes more than this many lines without
+  # nesting, then invalidate the layout (and nest)
+  max_rows_cmdline = 2
+
+  # If true, separate flow control names from their parentheses with a space
+  separate_ctrl_name_with_space = False
+
+  # If true, separate function names from parentheses with a space
+  separate_fn_name_with_space = False
+
+  # If a statement is wrapped to more than one line, than dangle the closing
+  # parenthesis on its own line.
+  dangle_parens = False
+
+  # If the trailing parenthesis must be 'dangled' on its on line, then align it
+  # to this reference: `prefix`: the start of the statement,  `prefix-indent`:
+  # the start of the statement, plus one indentation  level, `child`: align to
+  # the column of the arguments
+  dangle_align = 'prefix'
+
+  # If the statement spelling length (including space and parenthesis) is
+  # smaller than this amount, then force reject nested layouts.
+  min_prefix_chars = 4
+
+  # If the statement spelling length (including space and parenthesis) is larger
+  # than the tab width by more than this amount, then force reject un-nested
+  # layouts.
+  max_prefix_chars = 10
+
+  # If a candidate layout is wrapped horizontally but it exceeds this many
+  # lines, then reject the layout.
+  max_lines_hwrap = 2
+
+  # What style line endings to use in the output.
+  line_ending = 'unix'
+
+  # Format command names consistently as 'lower' or 'upper' case
+  command_case = 'canonical'
+
+  # Format keywords consistently as 'lower' or 'upper' case
+  keyword_case = 'unchanged'
+
+  # A list of command names which should always be wrapped
+  always_wrap = []
+
+  # If true, the argument lists which are known to be sortable will be sorted
+  # lexicographicall
+  enable_sort = True
+
+  # If true, the parsers may infer whether or not an argument list is sortable
+  # (without annotation).
+  autosort = False
+
+  # By default, if cmake-format cannot successfully fit everything into the
+  # desired linewidth it will apply the last, most agressive attempt that it
+  # made. If this flag is True, however, cmake-format will print error, exit
+  # with non-zero status code, and write-out nothing
+  require_valid_layout = False
+
+  # A dictionary mapping layout nodes to a list of wrap decisions. See the
+  # documentation for more information.
+  layout_passes = {}
+
+# ------------------------------------------------
+# Options affecting comment reflow and formatting.
+# ------------------------------------------------
+with section("markup"):
+
+  # What character to use for bulleted lists
+  bullet_char = '*'
+
+  # What character to use as punctuation after numerals in an enumerated list
+  enum_char = '.'
+
+  # If comment markup is enabled, don't reflow the first comment block in each
+  # listfile. Use this to preserve formatting of your copyright/license
+  # statements.
+  first_comment_is_literal = True
+
+  # If comment markup is enabled, don't reflow any comment block which matches
+  # this (regex) pattern. Default is `None` (disabled).
+  literal_comment_pattern = None
+
+  # Regular expression to match preformat fences in comments default=
+  # ``r'^\s*([`~]{3}[`~]*)(.*)$'``
+  fence_pattern = '^\\s*([`~]{3}[`~]*)(.*)$'
+
+  # Regular expression to match rulers in comments default=
+  # ``r'^\s*[^\w\s]{3}.*[^\w\s]{3}$'``
+  ruler_pattern = '^\\s*[^\\w\\s]{3}.*[^\\w\\s]{3}$'
+
+  # If a comment line matches starts with this pattern then it is explicitly a
+  # trailing comment for the preceeding argument. Default is '#<'
+  explicit_trailing_pattern = '#<'
+
+  # If a comment line starts with at least this many consecutive hash
+  # characters, then don't lstrip() them off. This allows for lazy hash rulers
+  # where the first hash char is not separated by space
+  hashruler_min_length = 10
+
+  # If true, then insert a space between the first hash char and remaining hash
+  # chars in a hash ruler, and normalize its length to fill the column
+  canonicalize_hashrulers = True
+
+  # enable comment markup parsing and reflow
+  enable_markup = True
+
+# ----------------------------
+# Options affecting the linter
+# ----------------------------
+with section("lint"):
+
+  # a list of lint codes to disable
+  disabled_codes = []
+
+  # regular expression pattern describing valid function names
+  function_pattern = '[0-9a-z_]+'
+
+  # regular expression pattern describing valid macro names
+  macro_pattern = '[0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for variables with global
+  # (cache) scope
+  global_var_pattern = '[A-Z][0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for variables with global
+  # scope (but internal semantic)
+  internal_var_pattern = '_[A-Z][0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for variables with local
+  # scope
+  local_var_pattern = '[a-z][a-z0-9_]+'
+
+  # regular expression pattern describing valid names for privatedirectory
+  # variables
+  private_var_pattern = '_[0-9a-z_]+'
+
+  # regular expression pattern describing valid names for public directory
+  # variables
+  public_var_pattern = '[A-Z][0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for function/macro
+  # arguments and loop variables.
+  argument_var_pattern = '[a-z][a-z0-9_]+'
+
+  # regular expression pattern describing valid names for keywords used in
+  # functions or macros
+  keyword_pattern = '[A-Z][0-9A-Z_]+'
+
+  # In the heuristic for C0201, how many conditionals to match within a loop in
+  # before considering the loop a parser.
+  max_conditionals_custom_parser = 2
+
+  # Require at least this many newlines between statements
+  min_statement_spacing = 1
+
+  # Require no more than this many newlines between statements
+  max_statement_spacing = 2
+  max_returns = 6
+  max_branches = 12
+  max_arguments = 5
+  max_localvars = 15
+  max_statements = 50
+
+# -------------------------------
+# Options affecting file encoding
+# -------------------------------
+with section("encode"):
+
+  # If true, emit the unicode byte-order mark (BOM) at the start of the file
+  emit_byteorder_mark = False
+
+  # Specify the encoding of the input file. Defaults to utf-8
+  input_encoding = 'utf-8'
+
+  # Specify the encoding of the output file. Defaults to utf-8. Note that cmake
+  # only claims to support utf-8 so be careful when using anything else
+  output_encoding = 'utf-8'
+
+# -------------------------------------
+# Miscellaneous configurations options.
+# -------------------------------------
+with section("misc"):
+
+  # A dictionary containing any per-command configuration overrides. Currently
+  # only `command_case` is supported.
+  per_command = {}

.gitattributes

@@ -0,0 +1,6 @@
+.gitattributes export-ignore
+.gitignore export-ignore
+.mailmap export-ignore
+*.bat text eol=crlf
+*.pdf -text -diff
+*.ppm -text -diff

.gitignore

@@ -0,0 +1,56 @@
+*.l[ao]
+*.[ao]
+*.pc
+.DS_Store
+.deps
+.idea
+.libs
+.vscode
+/aclocal.m4
+/ar-lib
+/autom4te.cache
+/compile
+/config.*
+/configure
+/depcomp
+/dist
+/install-sh
+/libtool
+/ltmain.sh
+/missing
+/mkinstalldirs
+/stamp-h1
+Makefile
+Makefile.in
+examples/anim_diff
+examples/anim_dump
+examples/[cdv]webp
+examples/gif2webp
+examples/img2webp
+examples/webpinfo
+examples/webpmux
+src/webp/config.h*
+src/webp/stamp-h1
+/output
+/doc/output
+*.idb
+*.pdb
+/iosbuild
+/xcframeworkbuild
+/WebP*.*framework
+CMakeCache.txt
+CMakeFiles/
+cmake_install.cmake
+.gradle
+/build
+extras/get_disto
+extras/vwebp_sdl
+extras/webp_quality
+tests/fuzzer/advanced_api_fuzzer
+tests/fuzzer/animation_api_fuzzer
+tests/fuzzer/animdecoder_fuzzer
+tests/fuzzer/animencoder_fuzzer
+tests/fuzzer/demux_api_fuzzer
+tests/fuzzer/enc_dec_fuzzer
+tests/fuzzer/mux_demux_api_fuzzer
+tests/fuzzer/simple_api_fuzzer

.mailmap

@@ -0,0 +1,19 @@
+Johann Koenig <johann.koenig@duck.com>
+Johann Koenig <johann.koenig@duck.com> <johannkoenig@google.com>
+Mikołaj Zalewski <mikolajz@google.com>
+Pascal Massimino <pascal.massimino@gmail.com>
+Pascal Massimino <pascal.massimino@gmail.com> <skal@google.com>
+Vikas Arora <vikasa@google.com>
+<vikasa@google.com> <vikasa@gmail.com>
+<vikasa@google.com> <vikaas.arora@gmail.com>
+<slobodan.prijic@imgtec.com> <Slobodan.Prijic@imgtec.com>
+<vrabaud@google.com> <vincent.rabaud@gmail.com>
+Vincent Rabaud <vrabaud@google.com>
+Tamar Levy <tamar.levy@intel.com>
+<qrczak@google.com> <qrczak>
+Hui Su <huisu@google.com>
+James Zern <jzern@google.com>
+Roberto Alanis <alanisbaez@google.com>
+Brian Ledger <brianpl@google.com>
+Maryla Ustarroz-Calonge <maryla@google.com>
+Yannis Guyon <yguyon@google.com>

.pylintrc

@@ -0,0 +1,441 @@
+# This Pylint rcfile contains a best-effort configuration to uphold the
+# best-practices and style described in the Google Python style guide:
+#   https://google.github.io/styleguide/pyguide.html
+#
+# Its canonical open-source location is:
+#   https://google.github.io/styleguide/pylintrc
+
+[MASTER]
+
+# Files or directories to be skipped. They should be base names, not paths.
+ignore=third_party
+
+# Files or directories matching the regex patterns are skipped. The regex
+# matches against base names, not paths.
+ignore-patterns=
+
+# Pickle collected data for later comparisons.
+persistent=no
+
+# List of plugins (as comma separated values of python modules names) to load,
+# usually to register additional checkers.
+load-plugins=
+
+# Use multiple processes to speed up Pylint.
+jobs=4
+
+# Allow loading of arbitrary C extensions. Extensions are imported into the
+# active Python interpreter and may run arbitrary code.
+unsafe-load-any-extension=no
+
+
+[MESSAGES CONTROL]
+
+# Only show warnings with the listed confidence levels. Leave empty to show
+# all. Valid levels: HIGH, INFERENCE, INFERENCE_FAILURE, UNDEFINED
+confidence=
+
+# Enable the message, report, category or checker with the given id(s). You can
+# either give multiple identifier separated by comma (,) or put this option
+# multiple time (only on the command line, not in the configuration file where
+# it should appear only once). See also the "--disable" option for examples.
+#enable=
+
+# Disable the message, report, category or checker with the given id(s). You
+# can either give multiple identifiers separated by comma (,) or put this
+# option multiple times (only on the command line, not in the configuration
+# file where it should appear only once).You can also use "--disable=all" to
+# disable everything first and then reenable specific checks. For example, if
+# you want to run only the similarities checker, you can use "--disable=all
+# --enable=similarities". If you want to run only the classes checker, but have
+# no Warning level messages displayed, use"--disable=all --enable=classes
+# --disable=W"
+disable=abstract-method,
+        apply-builtin,
+        arguments-differ,
+        attribute-defined-outside-init,
+        backtick,
+        bad-option-value,
+        basestring-builtin,
+        buffer-builtin,
+        c-extension-no-member,
+        consider-using-enumerate,
+        cmp-builtin,
+        cmp-method,
+        coerce-builtin,
+        coerce-method,
+        delslice-method,
+        div-method,
+        duplicate-code,
+        eq-without-hash,
+        execfile-builtin,
+        file-builtin,
+        filter-builtin-not-iterating,
+        fixme,
+        getslice-method,
+        global-statement,
+        hex-method,
+        idiv-method,
+        implicit-str-concat-in-sequence,
+        import-error,
+        import-self,
+        import-star-module-level,
+        inconsistent-return-statements,
+        input-builtin,
+        intern-builtin,
+        invalid-str-codec,
+        locally-disabled,
+        long-builtin,
+        long-suffix,
+        map-builtin-not-iterating,
+        misplaced-comparison-constant,
+        missing-function-docstring,
+        metaclass-assignment,
+        next-method-called,
+        next-method-defined,
+        no-absolute-import,
+        no-else-break,
+        no-else-continue,
+        no-else-raise,
+        no-else-return,
+        no-init,  # added
+        no-member,
+        no-name-in-module,
+        no-self-use,
+        nonzero-method,
+        oct-method,
+        old-division,
+        old-ne-operator,
+        old-octal-literal,
+        old-raise-syntax,
+        parameter-unpacking,
+        print-statement,
+        raising-string,
+        range-builtin-not-iterating,
+        raw_input-builtin,
+        rdiv-method,
+        reduce-builtin,
+        relative-import,
+        reload-builtin,
+        round-builtin,
+        setslice-method,
+        signature-differs,
+        standarderror-builtin,
+        suppressed-message,
+        sys-max-int,
+        too-few-public-methods,
+        too-many-ancestors,
+        too-many-arguments,
+        too-many-boolean-expressions,
+        too-many-branches,
+        too-many-instance-attributes,
+        too-many-locals,
+        too-many-nested-blocks,
+        too-many-public-methods,
+        too-many-return-statements,
+        too-many-statements,
+        trailing-newlines,
+        unichr-builtin,
+        unicode-builtin,
+        unnecessary-pass,
+        unpacking-in-except,
+        useless-else-on-loop,
+        useless-object-inheritance,
+        useless-suppression,
+        using-cmp-argument,
+        wrong-import-order,
+        xrange-builtin,
+        zip-builtin-not-iterating,
+
+
+[REPORTS]
+
+# Set the output format. Available formats are text, parseable, colorized, msvs
+# (visual studio) and html. You can also give a reporter class, eg
+# mypackage.mymodule.MyReporterClass.
+output-format=text
+
+# Put messages in a separate file for each module / package specified on the
+# command line instead of printing them on stdout. Reports (if any) will be
+# written in a file name "pylint_global.[txt|html]". This option is deprecated
+# and it will be removed in Pylint 2.0.
+files-output=no
+
+# Tells whether to display a full report or only the messages
+reports=no
+
+# Python expression which should return a note less than 10 (10 is the highest
+# note). You have access to the variables errors warning, statement which
+# respectively contain the number of errors / warnings messages and the total
+# number of statements analyzed. This is used by the global evaluation report
+# (RP0004).
+evaluation=10.0 - ((float(5 * error + warning + refactor + convention) / statement) * 10)
+
+# Template used to display messages. This is a python new-style format string
+# used to format the message information. See doc for all details
+#msg-template=
+
+
+[BASIC]
+
+# Good variable names which should always be accepted, separated by a comma
+good-names=main,_,PRESUBMIT
+
+# Bad variable names which should always be refused, separated by a comma
+bad-names=
+
+# Colon-delimited sets of names that determine each other's naming style when
+# the name regexes allow several styles.
+name-group=
+
+# Include a hint for the correct naming format with invalid-name
+include-naming-hint=no
+
+# List of decorators that produce properties, such as abc.abstractproperty. Add
+# to this list to register other decorators that produce valid properties.
+property-classes=abc.abstractproperty,cached_property.cached_property,cached_property.threaded_cached_property,cached_property.cached_property_with_ttl,cached_property.threaded_cached_property_with_ttl
+
+# Regular expression matching correct function names
+function-rgx=^(?:(?P<exempt>setUp|tearDown|setUpModule|tearDownModule)|(?P<camel_case>_?[A-Z][a-zA-Z0-9]*)|(?P<snake_case>_?[a-z][a-z0-9_]*))$
+
+# Regular expression matching correct variable names
+variable-rgx=^[a-z][a-z0-9_]*$
+
+# Regular expression matching correct constant names
+const-rgx=^(_?[A-Z][A-Z0-9_]*|__[a-z0-9_]+__|_?[a-z][a-z0-9_]*)$
+
+# Regular expression matching correct attribute names
+attr-rgx=^_{0,2}[a-z][a-z0-9_]*$
+
+# Regular expression matching correct argument names
+argument-rgx=^[a-z][a-z0-9_]*$
+
+# Regular expression matching correct class attribute names
+class-attribute-rgx=^(_?[A-Z][A-Z0-9_]*|__[a-z0-9_]+__|_?[a-z][a-z0-9_]*)$
+
+# Regular expression matching correct inline iteration names
+inlinevar-rgx=^[a-z][a-z0-9_]*$
+
+# Regular expression matching correct class names
+class-rgx=^_?[A-Z][a-zA-Z0-9]*$
+
+# Regular expression matching correct module names
+module-rgx=^(_?[a-z][a-z0-9_]*|__init__)$
+
+# Regular expression matching correct method names
+method-rgx=(?x)^(?:(?P<exempt>_[a-z0-9_]+__|runTest|setUp|tearDown|setUpTestCase|tearDownTestCase|setupSelf|tearDownClass|setUpClass|(test|assert)_*[A-Z0-9][a-zA-Z0-9_]*|next)|(?P<camel_case>_{0,2}[A-Z][a-zA-Z0-9_]*)|(?P<snake_case>_{0,2}[a-z][a-z0-9_]*))$
+
+# Regular expression which should only match function or class names that do
+# not require a docstring.
+no-docstring-rgx=(__.*__|main|test.*|.*test|.*Test)$
+
+# Minimum line length for functions/classes that require docstrings, shorter
+# ones are exempt.
+docstring-min-length=10
+
+
+[TYPECHECK]
+
+# List of decorators that produce context managers, such as
+# contextlib.contextmanager. Add to this list to register other decorators that
+# produce valid context managers.
+contextmanager-decorators=contextlib.contextmanager,contextlib2.contextmanager
+
+# Tells whether missing members accessed in mixin class should be ignored. A
+# mixin class is detected if its name ends with "mixin" (case insensitive).
+ignore-mixin-members=yes
+
+# List of module names for which member attributes should not be checked
+# (useful for modules/projects where namespaces are manipulated during runtime
+# and thus existing member attributes cannot be deduced by static analysis. It
+# supports qualified module names, as well as Unix pattern matching.
+ignored-modules=
+
+# List of class names for which member attributes should not be checked (useful
+# for classes with dynamically set attributes). This supports the use of
+# qualified names.
+ignored-classes=optparse.Values,thread._local,_thread._local
+
+# List of members which are set dynamically and missed by pylint inference
+# system, and so shouldn't trigger E1101 when accessed. Python regular
+# expressions are accepted.
+generated-members=
+
+
+[FORMAT]
+
+# Maximum number of characters on a single line.
+max-line-length=80
+
+# TODO(https://github.com/PyCQA/pylint/issues/3352): Direct pylint to exempt
+# lines made too long by directives to pytype.
+
+# Regexp for a line that is allowed to be longer than the limit.
+ignore-long-lines=(?x)(
+  ^\s*(\#\ )?<?https?://\S+>?$|
+  ^\s*(from\s+\S+\s+)?import\s+.+$)
+
+# Allow the body of an if to be on the same line as the test if there is no
+# else.
+single-line-if-stmt=yes
+
+# List of optional constructs for which whitespace checking is disabled. `dict-
+# separator` is used to allow tabulation in dicts, etc.: {1  : 1,\n222: 2}.
+# `trailing-comma` allows a space between comma and closing bracket: (a, ).
+# `empty-line` allows space-only lines.
+no-space-check=
+
+# Maximum number of lines in a module
+max-module-lines=99999
+
+# String used as indentation unit.  The internal Google style guide mandates 2
+# spaces.  Google's externaly-published style guide says 4, consistent with
+# PEP 8.  Here, we use 2 spaces, for conformity with many open-sourced Google
+# projects (like TensorFlow).
+indent-string='  '
+
+# Number of spaces of indent required inside a hanging  or continued line.
+indent-after-paren=4
+
+# Expected format of line ending, e.g. empty (any line ending), LF or CRLF.
+expected-line-ending-format=
+
+
+[MISCELLANEOUS]
+
+# List of note tags to take in consideration, separated by a comma.
+notes=TODO
+
+
+[STRING]
+
+# This flag controls whether inconsistent-quotes generates a warning when the
+# character used as a quote delimiter is used inconsistently within a module.
+check-quote-consistency=yes
+
+
+[VARIABLES]
+
+# Tells whether we should check for unused import in __init__ files.
+init-import=no
+
+# A regular expression matching the name of dummy variables (i.e. expectedly
+# not used).
+dummy-variables-rgx=^\*{0,2}(_$|unused_|dummy_)
+
+# List of additional names supposed to be defined in builtins. Remember that
+# you should avoid to define new builtins when possible.
+additional-builtins=
+
+# List of strings which can identify a callback function by name. A callback
+# name must start or end with one of those strings.
+callbacks=cb_,_cb
+
+# List of qualified module names which can have objects that can redefine
+# builtins.
+redefining-builtins-modules=six,six.moves,past.builtins,future.builtins,functools
+
+
+[LOGGING]
+
+# Logging modules to check that the string format arguments are in logging
+# function parameter format
+logging-modules=logging,absl.logging,tensorflow.io.logging
+
+
+[SIMILARITIES]
+
+# Minimum lines number of a similarity.
+min-similarity-lines=4
+
+# Ignore comments when computing similarities.
+ignore-comments=yes
+
+# Ignore docstrings when computing similarities.
+ignore-docstrings=yes
+
+# Ignore imports when computing similarities.
+ignore-imports=no
+
+
+[SPELLING]
+
+# Spelling dictionary name. Available dictionaries: none. To make it working
+# install python-enchant package.
+spelling-dict=
+
+# List of comma separated words that should not be checked.
+spelling-ignore-words=
+
+# A path to a file that contains private dictionary; one word per line.
+spelling-private-dict-file=
+
+# Tells whether to store unknown words to indicated private dictionary in
+# --spelling-private-dict-file option instead of raising a message.
+spelling-store-unknown-words=no
+
+
+[IMPORTS]
+
+# Deprecated modules which should not be used, separated by a comma
+deprecated-modules=regsub,
+                   TERMIOS,
+                   Bastion,
+                   rexec,
+                   sets
+
+# Create a graph of every (i.e. internal and external) dependencies in the
+# given file (report RP0402 must not be disabled)
+import-graph=
+
+# Create a graph of external dependencies in the given file (report RP0402 must
+# not be disabled)
+ext-import-graph=
+
+# Create a graph of internal dependencies in the given file (report RP0402 must
+# not be disabled)
+int-import-graph=
+
+# Force import order to recognize a module as part of the standard
+# compatibility libraries.
+known-standard-library=
+
+# Force import order to recognize a module as part of a third party library.
+known-third-party=enchant, absl
+
+# Analyse import fallback blocks. This can be used to support both Python 2 and
+# 3 compatible code, which means that the block might have code that exists
+# only in one or another interpreter, leading to false positives when analysed.
+analyse-fallback-blocks=no
+
+
+[CLASSES]
+
+# List of method names used to declare (i.e. assign) instance attributes.
+defining-attr-methods=__init__,
+                      __new__,
+                      setUp
+
+# List of member names, which should be excluded from the protected access
+# warning.
+exclude-protected=_asdict,
+                  _fields,
+                  _replace,
+                  _source,
+                  _make
+
+# List of valid names for the first argument in a class method.
+valid-classmethod-first-arg=cls,
+                            class_
+
+# List of valid names for the first argument in a metaclass class method.
+valid-metaclass-classmethod-first-arg=mcs
+
+
+[EXCEPTIONS]
+
+# Exceptions that will emit a warning when being caught. Defaults to
+# "Exception"
+overgeneral-exceptions=StandardError,
+                       Exception,
+                       BaseException

.style.yapf

@@ -0,0 +1,2 @@
+[style]
+based_on_style = yapf

AUTHORS

@@ -0,0 +1,60 @@
+Contributors:
+- Aidan O'Loan (aidanol at gmail dot com)
+- Alan Browning (browning at google dot com)
+- Alexandru Ardelean (ardeleanalex at gmail dot com)
+- Brian Ledger (brianpl at google dot com)
+- Charles Munger (clm at google dot com)
+- Cheng Yi (cyi at google dot com)
+- Christian Duvivier (cduvivier at google dot com)
+- Christopher Degawa (ccom at randomderp dot com)
+- Clement Courbet (courbet at google dot com)
+- Djordje Pesut (djordje dot pesut at imgtec dot com)
+- Frank Barchard (fbarchard at google dot com)
+- Hui Su (huisu at google dot com)
+- H. Vetinari (h dot vetinari at gmx dot com)
+- Ilya Kurdyukov (jpegqs at gmail dot com)
+- Ingvar Stepanyan (rreverser at google dot com)
+- James Zern (jzern at google dot com)
+- Jan Engelhardt (jengelh at medozas dot de)
+- Jehan (jehan at girinstud dot io)
+- Jeremy Maitin-Shepard (jbms at google dot com)
+- Johann Koenig (johann dot koenig at duck dot com)
+- Jovan Zelincevic (jovan dot zelincevic at imgtec dot com)
+- Jyrki Alakuijala (jyrki at google dot com)
+- Konstantin Ivlev (tomskside at gmail dot com)
+- Lode Vandevenne (lode at google dot com)
+- Lou Quillio (louquillio at google dot com)
+- Mans Rullgard (mans at mansr dot com)
+- Marcin Kowalczyk (qrczak at google dot com)
+- Martin Olsson (mnemo at minimum dot se)
+- Maryla Ustarroz-Calonge (maryla at google dot com)
+- Mikołaj Zalewski (mikolajz at google dot com)
+- Mislav Bradac (mislavm at google dot com)
+- Nico Weber (thakis at chromium dot org)
+- Noel Chromium (noel at chromium dot org)
+- Nozomi Isozaki (nontan at pixiv dot co dot jp)
+- Oliver Wolff (oliver dot wolff at qt dot io)
+- Owen Rodley (orodley at google dot com)
+- Parag Salasakar (img dot mips1 at gmail dot com)
+- Pascal Massimino (pascal dot massimino at gmail dot com)
+- Paweł Hajdan, Jr (phajdan dot jr at chromium dot org)
+- Pierre Joye (pierre dot php at gmail dot com)
+- Roberto Alanis (alanisbaez at google dot com)
+- Sam Clegg (sbc at chromium dot org)
+- Scott Hancher (seh at google dot com)
+- Scott LaVarnway (slavarnway at google dot com)
+- Scott Talbot (s at chikachow dot org)
+- Slobodan Prijic (slobodan dot prijic at imgtec dot com)
+- Somnath Banerjee (somnath dot banerjee at gmail dot com)
+- Sriraman Tallam (tmsriram at google dot com)
+- Tamar Levy (tamar dot levy at intel dot com)
+- Thiago Perrotta (tperrotta at google dot com)
+- Timothy Gu (timothygu99 at gmail dot com)
+- Urvang Joshi (urvang at google dot com)
+- Vikas Arora (vikasa at google dot com)
+- Vincent Rabaud (vrabaud at google dot com)
+- Vlad Tsyrklevich (vtsyrklevich at chromium dot org)
+- Wan-Teh Chang (wtc at google dot com)
+- Yang Zhang (yang dot zhang at arm dot com)
+- Yannis Guyon (yguyon at google dot com)
+- Zhi An Ng (zhin at chromium dot org)

Android.mk

@@ -0,0 +1,295 @@
+# Ignore this file during non-NDK builds.
+ifdef NDK_ROOT
+LOCAL_PATH := $(call my-dir)
+
+WEBP_CFLAGS := -Wall -DANDROID -DHAVE_MALLOC_H -DHAVE_PTHREAD -DWEBP_USE_THREAD
+WEBP_CFLAGS += -fvisibility=hidden
+
+ifeq ($(APP_OPTIM),release)
+  WEBP_CFLAGS += -finline-functions -ffast-math \
+                 -ffunction-sections -fdata-sections
+  ifeq ($(findstring clang,$(NDK_TOOLCHAIN_VERSION)),)
+    WEBP_CFLAGS += -frename-registers -s
+  endif
+endif
+
+# mips32 fails to build with clang from r14b
+# https://bugs.chromium.org/p/webp/issues/detail?id=343
+ifeq ($(findstring clang,$(NDK_TOOLCHAIN_VERSION)),clang)
+  ifeq ($(TARGET_ARCH),mips)
+    clang_version := $(shell $(TARGET_CC) --version)
+    ifneq ($(findstring clang version 3,$(clang_version)),)
+      WEBP_CFLAGS += -no-integrated-as
+    endif
+  endif
+endif
+
+ifneq ($(findstring armeabi-v7a, $(TARGET_ARCH_ABI)),)
+  # Setting LOCAL_ARM_NEON will enable -mfpu=neon which may cause illegal
+  # instructions to be generated for armv7a code. Instead target the neon code
+  # specifically.
+  NEON := c.neon
+  USE_CPUFEATURES := yes
+  WEBP_CFLAGS += -DHAVE_CPU_FEATURES_H
+else
+  NEON := c
+endif
+
+sharpyuv_srcs := \
+    sharpyuv/sharpyuv.c \
+    sharpyuv/sharpyuv_cpu.c \
+    sharpyuv/sharpyuv_csp.c \
+    sharpyuv/sharpyuv_dsp.c \
+    sharpyuv/sharpyuv_gamma.c \
+    sharpyuv/sharpyuv_neon.$(NEON) \
+    sharpyuv/sharpyuv_sse2.c \
+
+dec_srcs := \
+    src/dec/alpha_dec.c \
+    src/dec/buffer_dec.c \
+    src/dec/frame_dec.c \
+    src/dec/idec_dec.c \
+    src/dec/io_dec.c \
+    src/dec/quant_dec.c \
+    src/dec/tree_dec.c \
+    src/dec/vp8_dec.c \
+    src/dec/vp8l_dec.c \
+    src/dec/webp_dec.c \
+
+demux_srcs := \
+    src/demux/anim_decode.c \
+    src/demux/demux.c \
+
+dsp_dec_srcs := \
+    src/dsp/alpha_processing.c \
+    src/dsp/alpha_processing_mips_dsp_r2.c \
+    src/dsp/alpha_processing_neon.$(NEON) \
+    src/dsp/alpha_processing_sse2.c \
+    src/dsp/alpha_processing_sse41.c \
+    src/dsp/cpu.c \
+    src/dsp/dec.c \
+    src/dsp/dec_clip_tables.c \
+    src/dsp/dec_mips32.c \
+    src/dsp/dec_mips_dsp_r2.c \
+    src/dsp/dec_msa.c \
+    src/dsp/dec_neon.$(NEON) \
+    src/dsp/dec_sse2.c \
+    src/dsp/dec_sse41.c \
+    src/dsp/filters.c \
+    src/dsp/filters_mips_dsp_r2.c \
+    src/dsp/filters_msa.c \
+    src/dsp/filters_neon.$(NEON) \
+    src/dsp/filters_sse2.c \
+    src/dsp/lossless.c \
+    src/dsp/lossless_mips_dsp_r2.c \
+    src/dsp/lossless_msa.c \
+    src/dsp/lossless_neon.$(NEON) \
+    src/dsp/lossless_sse2.c \
+    src/dsp/lossless_sse41.c \
+    src/dsp/rescaler.c \
+    src/dsp/rescaler_mips32.c \
+    src/dsp/rescaler_mips_dsp_r2.c \
+    src/dsp/rescaler_msa.c \
+    src/dsp/rescaler_neon.$(NEON) \
+    src/dsp/rescaler_sse2.c \
+    src/dsp/upsampling.c \
+    src/dsp/upsampling_mips_dsp_r2.c \
+    src/dsp/upsampling_msa.c \
+    src/dsp/upsampling_neon.$(NEON) \
+    src/dsp/upsampling_sse2.c \
+    src/dsp/upsampling_sse41.c \
+    src/dsp/yuv.c \
+    src/dsp/yuv_mips32.c \
+    src/dsp/yuv_mips_dsp_r2.c \
+    src/dsp/yuv_neon.$(NEON) \
+    src/dsp/yuv_sse2.c \
+    src/dsp/yuv_sse41.c \
+
+dsp_enc_srcs := \
+    src/dsp/cost.c \
+    src/dsp/cost_mips32.c \
+    src/dsp/cost_mips_dsp_r2.c \
+    src/dsp/cost_neon.$(NEON) \
+    src/dsp/cost_sse2.c \
+    src/dsp/enc.c \
+    src/dsp/enc_mips32.c \
+    src/dsp/enc_mips_dsp_r2.c \
+    src/dsp/enc_msa.c \
+    src/dsp/enc_neon.$(NEON) \
+    src/dsp/enc_sse2.c \
+    src/dsp/enc_sse41.c \
+    src/dsp/lossless_enc.c \
+    src/dsp/lossless_enc_mips32.c \
+    src/dsp/lossless_enc_mips_dsp_r2.c \
+    src/dsp/lossless_enc_msa.c \
+    src/dsp/lossless_enc_neon.$(NEON) \
+    src/dsp/lossless_enc_sse2.c \
+    src/dsp/lossless_enc_sse41.c \
+    src/dsp/ssim.c \
+    src/dsp/ssim_sse2.c \
+
+enc_srcs := \
+    src/enc/alpha_enc.c \
+    src/enc/analysis_enc.c \
+    src/enc/backward_references_cost_enc.c \
+    src/enc/backward_references_enc.c \
+    src/enc/config_enc.c \
+    src/enc/cost_enc.c \
+    src/enc/filter_enc.c \
+    src/enc/frame_enc.c \
+    src/enc/histogram_enc.c \
+    src/enc/iterator_enc.c \
+    src/enc/near_lossless_enc.c \
+    src/enc/picture_enc.c \
+    src/enc/picture_csp_enc.c \
+    src/enc/picture_psnr_enc.c \
+    src/enc/picture_rescale_enc.c \
+    src/enc/picture_tools_enc.c \
+    src/enc/predictor_enc.c \
+    src/enc/quant_enc.c \
+    src/enc/syntax_enc.c \
+    src/enc/token_enc.c \
+    src/enc/tree_enc.c \
+    src/enc/vp8l_enc.c \
+    src/enc/webp_enc.c \
+
+mux_srcs := \
+    src/mux/anim_encode.c \
+    src/mux/muxedit.c \
+    src/mux/muxinternal.c \
+    src/mux/muxread.c \
+
+utils_dec_srcs := \
+    src/utils/bit_reader_utils.c \
+    src/utils/color_cache_utils.c \
+    src/utils/filters_utils.c \
+    src/utils/huffman_utils.c \
+    src/utils/palette.c \
+    src/utils/quant_levels_dec_utils.c \
+    src/utils/random_utils.c \
+    src/utils/rescaler_utils.c \
+    src/utils/thread_utils.c \
+    src/utils/utils.c \
+
+utils_enc_srcs := \
+    src/utils/bit_writer_utils.c \
+    src/utils/huffman_encode_utils.c \
+    src/utils/quant_levels_utils.c \
+
+################################################################################
+# libwebpdecoder
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    $(dec_srcs) \
+    $(dsp_dec_srcs) \
+    $(utils_dec_srcs) \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_EXPORT_C_INCLUDES += $(LOCAL_PATH)/src
+
+# prefer arm over thumb mode for performance gains
+LOCAL_ARM_MODE := arm
+
+ifeq ($(USE_CPUFEATURES),yes)
+  LOCAL_STATIC_LIBRARIES := cpufeatures
+endif
+
+LOCAL_MODULE := webpdecoder_static
+
+include $(BUILD_STATIC_LIBRARY)
+
+ifeq ($(ENABLE_SHARED),1)
+include $(CLEAR_VARS)
+
+LOCAL_WHOLE_STATIC_LIBRARIES := webpdecoder_static
+
+LOCAL_MODULE := webpdecoder
+
+include $(BUILD_SHARED_LIBRARY)
+endif  # ENABLE_SHARED=1
+
+################################################################################
+# libwebp
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    $(sharpyuv_srcs) \
+    $(dsp_enc_srcs) \
+    $(enc_srcs) \
+    $(utils_enc_srcs) \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_EXPORT_C_INCLUDES += $(LOCAL_PATH)/src $(LOCAL_PATH)
+
+# prefer arm over thumb mode for performance gains
+LOCAL_ARM_MODE := arm
+
+LOCAL_WHOLE_STATIC_LIBRARIES := webpdecoder_static
+
+LOCAL_MODULE := webp
+
+ifeq ($(ENABLE_SHARED),1)
+  include $(BUILD_SHARED_LIBRARY)
+else
+  include $(BUILD_STATIC_LIBRARY)
+endif
+
+################################################################################
+# libwebpdemux
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := $(demux_srcs)
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_EXPORT_C_INCLUDES += $(LOCAL_PATH)/src
+
+# prefer arm over thumb mode for performance gains
+LOCAL_ARM_MODE := arm
+
+LOCAL_MODULE := webpdemux
+
+ifeq ($(ENABLE_SHARED),1)
+  LOCAL_SHARED_LIBRARIES := webp
+  include $(BUILD_SHARED_LIBRARY)
+else
+  LOCAL_STATIC_LIBRARIES := webp
+  include $(BUILD_STATIC_LIBRARY)
+endif
+
+################################################################################
+# libwebpmux
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := $(mux_srcs)
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_EXPORT_C_INCLUDES += $(LOCAL_PATH)/src
+
+# prefer arm over thumb mode for performance gains
+LOCAL_ARM_MODE := arm
+
+LOCAL_MODULE := webpmux
+
+ifeq ($(ENABLE_SHARED),1)
+  LOCAL_SHARED_LIBRARIES := webp
+  include $(BUILD_SHARED_LIBRARY)
+else
+  LOCAL_STATIC_LIBRARIES := webp
+  include $(BUILD_STATIC_LIBRARY)
+endif
+
+################################################################################
+
+WEBP_SRC_PATH := $(LOCAL_PATH)
+include $(WEBP_SRC_PATH)/imageio/Android.mk
+include $(WEBP_SRC_PATH)/examples/Android.mk
+
+ifeq ($(USE_CPUFEATURES),yes)
+  $(call import-module,android/cpufeatures)
+endif
+endif  # NDK_ROOT

CMakeLists.txt

@@ -0,0 +1,802 @@
+#  Copyright (c) 2020 Google LLC.
+#
+#  Use of this source code is governed by a BSD-style license
+#  that can be found in the LICENSE file in the root of the source
+#  tree. An additional intellectual property rights grant can be found
+#  in the file PATENTS.  All contributing project authors may
+#  be found in the AUTHORS file in the root of the source tree.
+
+if(APPLE)
+  cmake_minimum_required(VERSION 3.17)
+else()
+  cmake_minimum_required(VERSION 3.7)
+endif()
+
+if(POLICY CMP0072)
+  cmake_policy(SET CMP0072 NEW)
+endif()
+
+project(WebP C)
+
+# Options for coder / decoder executables.
+if(BUILD_SHARED_LIBS)
+  set(WEBP_LINK_STATIC_DEFAULT OFF)
+else()
+  set(WEBP_LINK_STATIC_DEFAULT ON)
+endif()
+option(WEBP_LINK_STATIC
+       "Link using static libraries. If OFF, use dynamic libraries."
+       ${WEBP_LINK_STATIC_DEFAULT})
+if(NOT EMSCRIPTEN)
+  # Disable SIMD on Emscripten by default, as it's a new unstable Wasm feature.
+  # Users can still explicitly opt-in to make a SIMD-enabled build.
+  set(WEBP_ENABLE_SIMD_DEFAULT ON)
+endif()
+option(WEBP_ENABLE_SIMD "Enable any SIMD optimization."
+       ${WEBP_ENABLE_SIMD_DEFAULT})
+option(WEBP_BUILD_ANIM_UTILS "Build animation utilities." ON)
+option(WEBP_BUILD_CWEBP "Build the cwebp command line tool." ON)
+option(WEBP_BUILD_DWEBP "Build the dwebp command line tool." ON)
+option(WEBP_BUILD_GIF2WEBP "Build the gif2webp conversion tool." ON)
+option(WEBP_BUILD_IMG2WEBP "Build the img2webp animation tool." ON)
+option(WEBP_BUILD_VWEBP "Build the vwebp viewer tool." ON)
+option(WEBP_BUILD_WEBPINFO "Build the webpinfo command line tool." ON)
+option(WEBP_BUILD_LIBWEBPMUX "Build the libwebpmux library." ON)
+option(WEBP_BUILD_WEBPMUX "Build the webpmux command line tool." ON)
+option(WEBP_BUILD_EXTRAS "Build extras." ON)
+option(WEBP_BUILD_WEBP_JS "Emscripten build of webp.js." OFF)
+option(WEBP_USE_THREAD "Enable threading support" ON)
+option(WEBP_NEAR_LOSSLESS "Enable near-lossless encoding" ON)
+option(WEBP_ENABLE_SWAP_16BIT_CSP "Enable byte swap for 16 bit colorspaces."
+       OFF)
+set(WEBP_BITTRACE "0" CACHE STRING "Bit trace mode (0=none, 1=bit, 2=bytes)")
+set_property(CACHE WEBP_BITTRACE PROPERTY STRINGS 0 1 2)
+
+if(WEBP_LINK_STATIC)
+  if(WIN32)
+    set(CMAKE_FIND_LIBRARY_SUFFIXES .lib .a ${CMAKE_FIND_LIBRARY_SUFFIXES})
+  else()
+    set(CMAKE_FIND_LIBRARY_SUFFIXES .a ${CMAKE_FIND_LIBRARY_SUFFIXES})
+  endif()
+  set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+  # vwebp does not compile on Ubuntu with static libraries so disabling it for
+  # now.
+  set(WEBP_BUILD_VWEBP OFF)
+endif()
+
+# Option needed for handling Unicode file names on Windows.
+if(WIN32)
+  option(WEBP_UNICODE "Build Unicode executables." ON)
+endif()
+
+if(WEBP_BUILD_WEBP_JS)
+  set(WEBP_BUILD_ANIM_UTILS OFF)
+  set(WEBP_BUILD_CWEBP OFF)
+  set(WEBP_BUILD_DWEBP OFF)
+  set(WEBP_BUILD_GIF2WEBP OFF)
+  set(WEBP_BUILD_IMG2WEBP OFF)
+  set(WEBP_BUILD_VWEBP OFF)
+  set(WEBP_BUILD_WEBPINFO OFF)
+  set(WEBP_BUILD_WEBPMUX OFF)
+  set(WEBP_BUILD_EXTRAS OFF)
+  set(WEBP_USE_THREAD OFF)
+
+  if(WEBP_ENABLE_SIMD)
+    message(NOTICE
+            "wasm2js does not support SIMD, disabling webp.js generation.")
+  endif()
+endif()
+
+set(SHARPYUV_DEP_LIBRARIES)
+set(SHARPYUV_DEP_INCLUDE_DIRS)
+set(WEBP_DEP_LIBRARIES)
+set(WEBP_DEP_INCLUDE_DIRS)
+
+if(NOT CMAKE_BUILD_TYPE)
+  set(CMAKE_BUILD_TYPE "Release"
+      CACHE STRING "Build type: Release, Debug, MinSizeRel or RelWithDebInfo"
+            FORCE)
+endif()
+
+# Include dependencies.
+if(WEBP_BUILD_ANIM_UTILS
+   OR WEBP_BUILD_CWEBP
+   OR WEBP_BUILD_DWEBP
+   OR WEBP_BUILD_EXTRAS
+   OR WEBP_BUILD_GIF2WEBP
+   OR WEBP_BUILD_IMG2WEBP)
+  set(WEBP_FIND_IMG_LIBS TRUE)
+else()
+  set(WEBP_FIND_IMG_LIBS FALSE)
+endif()
+include(cmake/deps.cmake)
+include(GNUInstallDirs)
+
+if(BUILD_SHARED_LIBS AND NOT DEFINED CMAKE_INSTALL_RPATH)
+  # Set the rpath to match autoconf/libtool behavior. Note this must be set
+  # before target creation.
+  set(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
+endif()
+
+# ##############################################################################
+# Options.
+if(WEBP_ENABLE_SWAP_16BIT_CSP)
+  add_definitions(-DWEBP_SWAP_16BIT_CSP=1)
+endif()
+
+if(NOT WEBP_BITTRACE STREQUAL "0")
+  add_definitions(-DBITTRACE=${WEBP_BITTRACE})
+endif()
+
+if(WEBP_UNICODE)
+  # Windows recommends setting both UNICODE and _UNICODE.
+  add_definitions(-DUNICODE -D_UNICODE)
+endif()
+
+if(MSVC AND BUILD_SHARED_LIBS)
+  add_definitions(-DWEBP_DLL)
+endif()
+
+# pkg-config variables used by *.pc.in.
+set(prefix ${CMAKE_INSTALL_PREFIX})
+set(exec_prefix "\${prefix}")
+if(IS_ABSOLUTE "${CMAKE_INSTALL_LIBDIR}")
+  set(libdir "${CMAKE_INSTALL_LIBDIR}")
+else()
+  set(libdir "\${exec_prefix}/${CMAKE_INSTALL_LIBDIR}")
+endif()
+if(IS_ABSOLUTE "${CMAKE_INSTALL_INCLUDEDIR}")
+  set(includedir "${CMAKE_INSTALL_INCLUDEDIR}")
+else()
+  set(includedir "\${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
+endif()
+set(PTHREAD_LIBS ${CMAKE_THREAD_LIBS_INIT})
+set(INSTALLED_LIBRARIES)
+
+if(MSVC)
+  # match the naming convention used by nmake
+  set(webp_libname_prefix "lib")
+  set(CMAKE_SHARED_LIBRARY_PREFIX "${webp_libname_prefix}")
+  set(CMAKE_IMPORT_LIBRARY_PREFIX "${webp_libname_prefix}")
+  set(CMAKE_STATIC_LIBRARY_PREFIX "${webp_libname_prefix}")
+endif()
+
+set(CMAKE_C_VISIBILITY_PRESET hidden)
+
+# ##############################################################################
+# Android only.
+if(ANDROID)
+  include_directories(${ANDROID_NDK}/sources/android/cpufeatures)
+  add_library(cpufeatures-webp STATIC
+              ${ANDROID_NDK}/sources/android/cpufeatures/cpu-features.c)
+  list(APPEND INSTALLED_LIBRARIES cpufeatures-webp)
+  target_link_libraries(cpufeatures-webp dl)
+  set(SHARPYUV_DEP_LIBRARIES ${SHARPYUV_DEP_LIBRARIES} cpufeatures-webp)
+  set(WEBP_DEP_LIBRARIES ${WEBP_DEP_LIBRARIES} cpufeatures-webp)
+  set(cpufeatures_include_dir ${ANDROID_NDK}/sources/android/cpufeatures)
+  set(SHARPYUV_DEP_INCLUDE_DIRS ${SHARPYUV_DEP_INCLUDE_DIRS}
+                                ${cpufeatures_include_dir})
+  set(WEBP_DEP_INCLUDE_DIRS ${WEBP_DEP_INCLUDE_DIRS} ${cpufeatures_include_dir})
+  add_definitions(-DHAVE_CPU_FEATURES_H=1)
+  set(HAVE_CPU_FEATURES_H 1)
+else()
+  set(HAVE_CPU_FEATURES_H 0)
+endif()
+
+function(configure_pkg_config FILE)
+  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/${FILE}.in"
+                 "${CMAKE_CURRENT_BINARY_DIR}/${FILE}" @ONLY)
+
+  if(HAVE_MATH_LIBRARY)
+    # MSVC doesn't have libm
+    file(READ ${CMAKE_CURRENT_BINARY_DIR}/${FILE} data)
+    string(REPLACE "-lm" "" data ${data})
+    file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/${FILE} ${data})
+  endif()
+
+  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${FILE}"
+          DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+endfunction()
+
+# ##############################################################################
+# WebP source files. Read the Makefile.am to get the source files.
+
+# We expect the Makefiles to define the sources as defined in the first regex.
+# E.g.: libimagedec_la_SOURCES  = image_dec.c image_dec.h
+function(parse_Makefile_am FOLDER VAR SRC_REGEX)
+  file(READ ${FOLDER}/Makefile.am MAKEFILE_AM)
+  string(REGEX MATCHALL "${SRC_REGEX}_SOURCES[ ]*\\+?=[ ]+[0-9a-z\\._ ]*"
+               FILES_PER_LINE ${MAKEFILE_AM})
+  set(SRCS ${${VAR}})
+  foreach(FILES ${FILES_PER_LINE})
+    string(FIND ${FILES} "=" OFFSET)
+    math(EXPR OFFSET "${OFFSET} + 2")
+    string(SUBSTRING ${FILES} ${OFFSET} -1 FILES)
+    if(FILES)
+      string(REGEX MATCHALL "[0-9a-z\\._]+" FILES ${FILES})
+      foreach(FILE ${FILES})
+        list(APPEND SRCS ${FOLDER}/${FILE})
+      endforeach()
+    endif()
+  endforeach()
+  set(${VAR} ${SRCS} PARENT_SCOPE)
+endfunction()
+
+set(WEBP_SRC_DIR ${CMAKE_CURRENT_SOURCE_DIR}/src)
+parse_makefile_am(${WEBP_SRC_DIR}/dec "WEBP_DEC_SRCS" "")
+parse_makefile_am(${WEBP_SRC_DIR}/demux "WEBP_DEMUX_SRCS" "")
+parse_makefile_am(${WEBP_SRC_DIR}/dsp "WEBP_DSP_COMMON_SRCS" "COMMON")
+parse_makefile_am(${WEBP_SRC_DIR}/dsp "WEBP_DSP_ENC_SRCS" "ENC")
+parse_makefile_am(${WEBP_SRC_DIR}/dsp "WEBP_DSP_ENC_SRCS" "dsp_[^ ]*")
+parse_makefile_am(${WEBP_SRC_DIR}/dsp "WEBP_DSP_DEC_SRCS" "decode_[^ ]*")
+parse_makefile_am(${WEBP_SRC_DIR}/enc "WEBP_ENC_SRCS" "")
+parse_makefile_am(${WEBP_SRC_DIR}/utils "WEBP_UTILS_COMMON_SRCS" "COMMON")
+parse_makefile_am(${WEBP_SRC_DIR}/utils "WEBP_UTILS_ENC_SRCS" "ENC")
+parse_makefile_am(${WEBP_SRC_DIR}/utils "WEBP_UTILS_DEC_SRCS" "decode_[^ ]*")
+
+# Remove the files specific to SIMD we don't use.
+foreach(FILE ${WEBP_SIMD_FILES_NOT_TO_INCLUDE})
+  list(REMOVE_ITEM WEBP_DSP_ENC_SRCS ${FILE})
+  list(REMOVE_ITEM WEBP_DSP_DEC_SRCS ${FILE})
+endforeach()
+
+# Generate the config.h file.
+configure_file(${CMAKE_CURRENT_LIST_DIR}/cmake/config.h.in
+               ${CMAKE_CURRENT_BINARY_DIR}/src/webp/config.h @ONLY)
+add_definitions(-DHAVE_CONFIG_H)
+
+# Set the version numbers.
+macro(set_version FILE TARGET_NAME NAME_IN_MAKEFILE)
+  file(READ ${CMAKE_CURRENT_SOURCE_DIR}/${FILE} SOURCE_FILE)
+  string(REGEX MATCH
+               "${NAME_IN_MAKEFILE}_la_LDFLAGS[^\n]* -version-info [0-9:]+" TMP
+               ${SOURCE_FILE})
+  string(REGEX MATCH "[0-9:]+" TMP ${TMP})
+  string(REGEX REPLACE ":" " " LT_VERSION ${TMP})
+
+  # See the libtool docs for more information:
+  # https://www.gnu.org/software/libtool/manual/libtool.html#Updating-version-info
+  #
+  # c=<current>, a=<age>, r=<revision>
+  #
+  # libtool generates a .so file as .so.[c-a].a.r, while -version-info c:r:a is
+  # passed to libtool.
+  #
+  # We set FULL = [c-a].a.r and MAJOR = [c-a].
+  separate_arguments(LT_VERSION)
+  list(GET LT_VERSION 0 LT_CURRENT)
+  list(GET LT_VERSION 1 LT_REVISION)
+  list(GET LT_VERSION 2 LT_AGE)
+  math(EXPR LT_CURRENT_MINUS_AGE "${LT_CURRENT} - ${LT_AGE}")
+
+  set_target_properties(
+    ${TARGET_NAME}
+    PROPERTIES VERSION ${LT_CURRENT_MINUS_AGE}.${LT_AGE}.${LT_REVISION}
+               SOVERSION ${LT_CURRENT_MINUS_AGE})
+  if(APPLE)
+    # For compatibility, set MACHO_COMPATIBILITY_VERSION and
+    # MACHO_CURRENT_VERSION to match libtool. These properties were introduced
+    # in 3.17:
+    # https://cmake.org/cmake/help/latest/prop_tgt/MACHO_COMPATIBILITY_VERSION.html
+    math(EXPR LIBWEBP_MACHO_COMPATIBILITY_VERSION "${LT_CURRENT} + 1")
+    set_target_properties(
+      ${TARGET_NAME}
+      PROPERTIES MACHO_COMPATIBILITY_VERSION
+                 ${LIBWEBP_MACHO_COMPATIBILITY_VERSION}
+                 MACHO_CURRENT_VERSION
+                 ${LIBWEBP_MACHO_COMPATIBILITY_VERSION}.${LT_REVISION})
+  endif()
+endmacro()
+
+# ##############################################################################
+# Build the webpdecoder library.
+
+# Creates a source file with an unused stub function in $CMAKE_BINARY_DIR and
+# adds it to the specified target. Currently used only with Xcode.
+#
+# See also:
+# https://cmake.org/cmake/help/v3.18/command/add_library.html#object-libraries
+# "Some native build systems (such as Xcode) may not like targets that have only
+# object files, so consider adding at least one real source file to any target
+# that references $<TARGET_OBJECTS:objlib>."
+function(libwebp_add_stub_file TARGET)
+  set(stub_source_dir "${CMAKE_BINARY_DIR}")
+  set(stub_source_file "${stub_source_dir}/libwebp_${TARGET}_stub.c")
+  set(stub_source_code
+      "// Generated file. DO NOT EDIT!\n"
+      "// C source file created for target ${TARGET}.\n"
+      "void libwebp_${TARGET}_stub_function(void)\;\n"
+      "void libwebp_${TARGET}_stub_function(void) {}\n")
+  file(WRITE "${stub_source_file}" ${stub_source_code})
+
+  target_sources(${TARGET} PRIVATE ${stub_source_file})
+endfunction()
+
+parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv "WEBP_SHARPYUV_SRCS" "")
+add_library(sharpyuv ${WEBP_SHARPYUV_SRCS})
+target_link_libraries(sharpyuv ${SHARPYUV_DEP_LIBRARIES})
+set_version(sharpyuv/Makefile.am sharpyuv sharpyuv)
+target_include_directories(
+  sharpyuv PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+                   ${CMAKE_CURRENT_SOURCE_DIR}/src)
+set_target_properties(
+  sharpyuv
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv/sharpyuv.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv/sharpyuv_csp.h")
+configure_pkg_config("sharpyuv/libsharpyuv.pc")
+install(
+  TARGETS sharpyuv
+  EXPORT ${PROJECT_NAME}Targets
+  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/webp/sharpyuv
+  INCLUDES
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+  ${CMAKE_INSTALL_INCLUDEDIR}/webp
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+
+if(MSVC)
+  # avoid security warnings for e.g., fopen() used in the examples.
+  add_definitions(-D_CRT_SECURE_NO_WARNINGS)
+else()
+  add_compile_options(-Wall)
+endif()
+include_directories(${WEBP_DEP_INCLUDE_DIRS})
+add_library(webpdecode OBJECT ${WEBP_DEC_SRCS})
+target_include_directories(webpdecode PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                              ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webpdspdecode OBJECT ${WEBP_DSP_COMMON_SRCS} ${WEBP_DSP_DEC_SRCS})
+target_include_directories(webpdspdecode PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                                 ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webputilsdecode OBJECT ${WEBP_UTILS_COMMON_SRCS}
+                                   ${WEBP_UTILS_DEC_SRCS})
+target_include_directories(webputilsdecode PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                                   ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(
+  webpdecoder $<TARGET_OBJECTS:webpdecode> $<TARGET_OBJECTS:webpdspdecode>
+              $<TARGET_OBJECTS:webputilsdecode>)
+if(XCODE)
+  libwebp_add_stub_file(webpdecoder)
+endif()
+target_link_libraries(webpdecoder ${WEBP_DEP_LIBRARIES})
+target_include_directories(
+  webpdecoder PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+  INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+            $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+set_target_properties(
+  webpdecoder
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+configure_pkg_config("src/libwebpdecoder.pc")
+
+# Build the webp library.
+add_library(webpencode OBJECT ${WEBP_ENC_SRCS})
+target_include_directories(
+  webpencode PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+                     ${CMAKE_CURRENT_SOURCE_DIR}/src)
+add_library(webpdsp OBJECT ${WEBP_DSP_COMMON_SRCS} ${WEBP_DSP_DEC_SRCS}
+                           ${WEBP_DSP_ENC_SRCS})
+target_include_directories(webpdsp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                           ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webputils OBJECT ${WEBP_UTILS_COMMON_SRCS} ${WEBP_UTILS_DEC_SRCS}
+                             ${WEBP_UTILS_ENC_SRCS})
+target_include_directories(webputils PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                             ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webp $<TARGET_OBJECTS:webpdecode> $<TARGET_OBJECTS:webpdsp>
+                 $<TARGET_OBJECTS:webpencode> $<TARGET_OBJECTS:webputils>)
+target_link_libraries(webp sharpyuv)
+if(XCODE)
+  libwebp_add_stub_file(webp)
+endif()
+target_link_libraries(webp ${WEBP_DEP_LIBRARIES})
+target_include_directories(
+  webp PRIVATE ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}
+  PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>
+         $<INSTALL_INTERFACE:include>)
+set_target_properties(
+  webp
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/encode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+# Make sure the OBJECT libraries are built with position independent code (it is
+# not ON by default).
+set_target_properties(webpdecode webpdspdecode webputilsdecode webpencode
+                      webpdsp webputils PROPERTIES POSITION_INDEPENDENT_CODE ON)
+configure_pkg_config("src/libwebp.pc")
+
+# Build the webp demux library.
+add_library(webpdemux ${WEBP_DEMUX_SRCS})
+target_link_libraries(webpdemux webp)
+target_include_directories(
+  webpdemux PRIVATE ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}
+  PUBLIC $<INSTALL_INTERFACE:include>)
+set_target_properties(
+  webpdemux
+  PROPERTIES
+    PUBLIC_HEADER
+    "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/demux.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux_types.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+configure_pkg_config("src/demux/libwebpdemux.pc")
+
+set_version(src/Makefile.am webp webp)
+set_version(src/Makefile.am webpdecoder webpdecoder)
+set_version(src/demux/Makefile.am webpdemux webpdemux)
+file(READ ${CMAKE_CURRENT_SOURCE_DIR}/configure.ac CONFIGURE_FILE)
+string(REGEX MATCH "AC_INIT\\([^\n]*\\[[0-9\\.]+\\]" TMP ${CONFIGURE_FILE})
+string(REGEX MATCH "[0-9\\.]+" PROJECT_VERSION ${TMP})
+
+# Define the libraries to install.
+list(APPEND INSTALLED_LIBRARIES webpdecoder webp webpdemux)
+
+# Deal with SIMD. Change the compile flags for SIMD files we use.
+list(LENGTH WEBP_SIMD_FILES_TO_INCLUDE WEBP_SIMD_FILES_TO_INCLUDE_LENGTH)
+math(EXPR WEBP_SIMD_FILES_TO_INCLUDE_RANGE
+     "${WEBP_SIMD_FILES_TO_INCLUDE_LENGTH}-1")
+
+foreach(I_FILE RANGE ${WEBP_SIMD_FILES_TO_INCLUDE_RANGE})
+  list(GET WEBP_SIMD_FILES_TO_INCLUDE ${I_FILE} FILE)
+  list(GET WEBP_SIMD_FLAGS_TO_INCLUDE ${I_FILE} SIMD_COMPILE_FLAG)
+  set_source_files_properties(${FILE} PROPERTIES COMPILE_FLAGS
+                                                 ${SIMD_COMPILE_FLAG})
+endforeach()
+
+if(NOT WEBP_BUILD_LIBWEBPMUX)
+  set(WEBP_BUILD_GIF2WEBP OFF)
+  set(WEBP_BUILD_IMG2WEBP OFF)
+  set(WEBP_BUILD_WEBPMUX OFF)
+endif()
+
+if(WEBP_BUILD_GIF2WEBP AND NOT GIF_FOUND)
+  set(WEBP_BUILD_GIF2WEBP OFF)
+endif()
+
+if(WEBP_BUILD_ANIM_UTILS AND NOT GIF_FOUND)
+  set(WEBP_BUILD_ANIM_UTILS OFF)
+endif()
+
+# Build the executables if asked for.
+if(WEBP_BUILD_ANIM_UTILS
+   OR WEBP_BUILD_CWEBP
+   OR WEBP_BUILD_DWEBP
+   OR WEBP_BUILD_GIF2WEBP
+   OR WEBP_BUILD_IMG2WEBP
+   OR WEBP_BUILD_VWEBP
+   OR WEBP_BUILD_WEBPMUX
+   OR WEBP_BUILD_WEBPINFO)
+  # Example utility library.
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "EXAMPLEUTIL_SRCS"
+                    "example_util_[^ ]*")
+  list(APPEND EXAMPLEUTIL_SRCS ${CMAKE_CURRENT_SOURCE_DIR}/examples/stopwatch.h)
+  add_library(exampleutil STATIC ${EXAMPLEUTIL_SRCS})
+  target_include_directories(
+    exampleutil PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>)
+
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/imageio "IMAGEIOUTILS_SRCS"
+                    "imageio_util_[^ ]*")
+  add_library(imageioutil STATIC ${IMAGEIOUTILS_SRCS})
+  target_link_libraries(imageioutil webp)
+  target_link_libraries(exampleutil imageioutil)
+
+  # Image-decoding utility library.
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/imageio "IMAGEDEC_SRCS"
+                    "imagedec_[^ ]*")
+  add_library(imagedec STATIC ${IMAGEDEC_SRCS})
+  target_link_libraries(imagedec imageioutil webpdemux webp
+                        ${WEBP_DEP_IMG_LIBRARIES})
+
+  # Image-encoding utility library.
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/imageio "IMAGEENC_SRCS"
+                    "imageenc_[^ ]*")
+  add_library(imageenc STATIC ${IMAGEENC_SRCS})
+  target_link_libraries(imageenc imageioutil webp)
+
+  set_property(
+    TARGET exampleutil imageioutil imagedec imageenc
+    PROPERTY INCLUDE_DIRECTORIES ${CMAKE_CURRENT_SOURCE_DIR}/src
+             ${CMAKE_CURRENT_BINARY_DIR}/src)
+endif()
+
+if(WEBP_BUILD_DWEBP)
+  # dwebp
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "DWEBP_SRCS" "dwebp")
+  add_executable(dwebp ${DWEBP_SRCS})
+  target_link_libraries(dwebp exampleutil imagedec imageenc)
+  target_include_directories(dwebp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+  install(TARGETS dwebp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_CWEBP)
+  # cwebp
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "CWEBP_SRCS" "cwebp")
+  add_executable(cwebp ${CWEBP_SRCS})
+  target_link_libraries(cwebp exampleutil imagedec webp)
+  target_include_directories(cwebp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src
+                                           ${CMAKE_CURRENT_SOURCE_DIR})
+  install(TARGETS cwebp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_LIBWEBPMUX)
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/src/mux "WEBP_MUX_SRCS" "")
+  add_library(libwebpmux ${WEBP_MUX_SRCS})
+  target_link_libraries(libwebpmux webp)
+  target_include_directories(libwebpmux PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                                ${CMAKE_CURRENT_SOURCE_DIR})
+  set_version(src/mux/Makefile.am libwebpmux webpmux)
+  set_target_properties(
+    libwebpmux
+    PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux_types.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h;")
+  set_target_properties(libwebpmux PROPERTIES OUTPUT_NAME webpmux)
+  list(APPEND INSTALLED_LIBRARIES libwebpmux)
+  configure_pkg_config("src/mux/libwebpmux.pc")
+endif()
+
+if(WEBP_BUILD_GIF2WEBP)
+  # gif2webp
+  include_directories(${WEBP_DEP_GIF_INCLUDE_DIRS})
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "GIF2WEBP_SRCS"
+                    "gif2webp")
+  add_executable(gif2webp ${GIF2WEBP_SRCS})
+  target_link_libraries(gif2webp exampleutil imageioutil webp libwebpmux
+                        ${WEBP_DEP_GIF_LIBRARIES})
+  target_include_directories(gif2webp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+  install(TARGETS gif2webp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_IMG2WEBP)
+  # img2webp
+  include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS})
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "IMG2WEBP_SRCS"
+                    "img2webp")
+  add_executable(img2webp ${IMG2WEBP_SRCS})
+  target_link_libraries(img2webp exampleutil imagedec imageioutil webp
+                        libwebpmux)
+  target_include_directories(img2webp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src
+                                              ${CMAKE_CURRENT_SOURCE_DIR})
+  install(TARGETS img2webp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_VWEBP)
+  # vwebp
+  find_package(GLUT)
+  if(GLUT_FOUND)
+    include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS})
+    parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "VWEBP_SRCS" "vwebp")
+    add_executable(vwebp ${VWEBP_SRCS})
+    target_link_libraries(
+      vwebp
+      ${OPENGL_LIBRARIES}
+      exampleutil
+      GLUT::GLUT
+      imageioutil
+      webp
+      webpdemux)
+    target_include_directories(
+      vwebp PRIVATE ${GLUT_INCLUDE_DIR} ${CMAKE_CURRENT_BINARY_DIR}/src
+                    ${OPENGL_INCLUDE_DIR})
+    install(TARGETS vwebp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+    if(${CMAKE_SYSTEM_NAME} STREQUAL "Darwin")
+      check_c_compiler_flag("-Wno-deprecated-declarations" HAS_NO_DEPRECATED)
+      if(HAS_NO_DEPRECATED)
+        target_compile_options(vwebp PRIVATE "-Wno-deprecated-declarations")
+      endif()
+    endif()
+  endif()
+endif()
+
+if(WEBP_BUILD_WEBPINFO)
+  # webpinfo
+  include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS})
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "WEBPINFO_SRCS"
+                    "webpinfo")
+  add_executable(webpinfo ${WEBPINFO_SRCS})
+  target_link_libraries(webpinfo exampleutil imageioutil)
+  target_include_directories(webpinfo PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src
+                                              ${CMAKE_CURRENT_SOURCE_DIR}/src)
+  install(TARGETS webpinfo RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_WEBPMUX)
+  # webpmux
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "WEBPMUX_SRCS"
+                    "webpmux")
+  add_executable(webpmux ${WEBPMUX_SRCS})
+  target_link_libraries(webpmux exampleutil imageioutil libwebpmux webp)
+  target_include_directories(webpmux PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+  install(TARGETS webpmux RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_EXTRAS)
+  set(EXTRAS_MAKEFILE "${CMAKE_CURRENT_SOURCE_DIR}/extras")
+  parse_makefile_am(${EXTRAS_MAKEFILE} "WEBP_EXTRAS_SRCS" "libwebpextras_la")
+  parse_makefile_am(${EXTRAS_MAKEFILE} "GET_DISTO_SRCS" "get_disto")
+  parse_makefile_am(${EXTRAS_MAKEFILE} "WEBP_QUALITY_SRCS" "webp_quality")
+  parse_makefile_am(${EXTRAS_MAKEFILE} "VWEBP_SDL_SRCS" "vwebp_sdl")
+
+  # libextras
+  add_library(extras STATIC ${WEBP_EXTRAS_SRCS})
+  target_include_directories(
+    extras PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+                   ${CMAKE_CURRENT_SOURCE_DIR}/src)
+
+  # get_disto
+  add_executable(get_disto ${GET_DISTO_SRCS})
+  target_link_libraries(get_disto imagedec)
+  target_include_directories(get_disto PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+                                               ${CMAKE_CURRENT_BINARY_DIR}/src)
+
+  # webp_quality
+  add_executable(webp_quality ${WEBP_QUALITY_SRCS})
+  target_link_libraries(webp_quality exampleutil imagedec extras)
+  target_include_directories(webp_quality PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+                                                  ${CMAKE_CURRENT_BINARY_DIR})
+
+  # vwebp_sdl
+  find_package(SDL)
+  if(WEBP_BUILD_VWEBP AND SDL_FOUND)
+    add_executable(vwebp_sdl ${VWEBP_SDL_SRCS})
+    target_link_libraries(vwebp_sdl ${SDL_LIBRARY} imageioutil webp)
+    target_include_directories(
+      vwebp_sdl PRIVATE ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}
+                        ${CMAKE_CURRENT_BINARY_DIR}/src ${SDL_INCLUDE_DIR})
+    set(WEBP_HAVE_SDL 1)
+    target_compile_definitions(vwebp_sdl PUBLIC WEBP_HAVE_SDL)
+  endif()
+endif()
+
+if(WEBP_BUILD_WEBP_JS)
+  # The default stack size changed from 5MB to 64KB in 3.1.27. See
+  # https://crbug.com/webp/614.
+  if(EMSCRIPTEN_VERSION VERSION_GREATER_EQUAL "3.1.27")
+    # TOTAL_STACK size was renamed to STACK_SIZE in 3.1.27. The old name was
+    # kept for compatibility, but prefer the new one in case it is removed in
+    # the future.
+    set(emscripten_stack_size "-sSTACK_SIZE=5MB")
+  else()
+    set(emscripten_stack_size "-sTOTAL_STACK=5MB")
+  endif()
+  # wasm2js does not support SIMD.
+  if(NOT WEBP_ENABLE_SIMD)
+    # JavaScript version
+    add_executable(webp_js ${CMAKE_CURRENT_SOURCE_DIR}/extras/webp_to_sdl.c)
+    target_link_libraries(webp_js webpdecoder SDL)
+    target_include_directories(webp_js PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
+    set(WEBP_HAVE_SDL 1)
+    set_target_properties(
+      webp_js
+      PROPERTIES LINK_FLAGS "-sWASM=0 ${emscripten_stack_size} \
+         -sEXPORTED_FUNCTIONS=_WebPToSDL -sINVOKE_RUN=0 \
+         -sEXPORTED_RUNTIME_METHODS=cwrap")
+    set_target_properties(webp_js PROPERTIES OUTPUT_NAME webp)
+    target_compile_definitions(webp_js PUBLIC EMSCRIPTEN WEBP_HAVE_SDL)
+  endif()
+
+  # WASM version
+  add_executable(webp_wasm ${CMAKE_CURRENT_SOURCE_DIR}/extras/webp_to_sdl.c)
+  target_link_libraries(webp_wasm webpdecoder SDL)
+  target_include_directories(webp_wasm PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
+  set_target_properties(
+    webp_wasm
+    PROPERTIES LINK_FLAGS "-sWASM=1 ${emscripten_stack_size} \
+       -sEXPORTED_FUNCTIONS=_WebPToSDL -sINVOKE_RUN=0 \
+       -sEXPORTED_RUNTIME_METHODS=cwrap")
+  target_compile_definitions(webp_wasm PUBLIC EMSCRIPTEN WEBP_HAVE_SDL)
+
+  target_compile_definitions(webpdspdecode PUBLIC EMSCRIPTEN)
+endif()
+
+if(WEBP_BUILD_ANIM_UTILS)
+  # anim_diff
+  include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS} ${WEBP_DEP_GIF_INCLUDE_DIRS})
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "ANIM_DIFF_SRCS"
+                    "anim_diff")
+  add_executable(anim_diff ${ANIM_DIFF_SRCS})
+  target_link_libraries(
+    anim_diff
+    exampleutil
+    imagedec
+    imageenc
+    imageioutil
+    webp
+    webpdemux
+    ${WEBP_DEP_GIF_LIBRARIES})
+  target_include_directories(anim_diff PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+
+  # anim_dump
+  include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS} ${WEBP_DEP_GIF_INCLUDE_DIRS})
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "ANIM_DUMP_SRCS"
+                    "anim_dump")
+  add_executable(anim_dump ${ANIM_DUMP_SRCS})
+  target_link_libraries(
+    anim_dump
+    exampleutil
+    imagedec
+    imageenc
+    imageioutil
+    webp
+    webpdemux
+    ${WEBP_DEP_GIF_LIBRARIES})
+  target_include_directories(anim_dump PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+endif()
+
+# Install the different headers and libraries.
+install(
+  TARGETS ${INSTALLED_LIBRARIES}
+  EXPORT ${PROJECT_NAME}Targets
+  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/webp
+  INCLUDES
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+set(ConfigPackageLocation ${CMAKE_INSTALL_DATADIR}/${PROJECT_NAME}/cmake/)
+install(EXPORT ${PROJECT_NAME}Targets NAMESPACE ${PROJECT_NAME}::
+        DESTINATION ${ConfigPackageLocation})
+
+# Create the CMake version file.
+include(CMakePackageConfigHelpers)
+write_basic_package_version_file(
+  "${CMAKE_CURRENT_BINARY_DIR}/WebPConfigVersion.cmake"
+  VERSION ${PACKAGE_VERSION} COMPATIBILITY AnyNewerVersion)
+
+# Create the Config file.
+include(CMakePackageConfigHelpers)
+# Fix libwebpmux reference. The target name libwebpmux is used for compatibility
+# purposes, but the library mentioned in WebPConfig.cmake should be the
+# unprefixed version. Note string(...) can be replaced with list(TRANSFORM ...)
+# if cmake_minimum_required is >= 3.12.
+string(REGEX REPLACE "libwebpmux" "webpmux" INSTALLED_LIBRARIES
+                     "${INSTALLED_LIBRARIES}")
+
+if(MSVC)
+  # For compatibility with nmake, MSVC builds use a custom prefix (lib) that
+  # needs to be included in the library name.
+  string(REGEX REPLACE "[A-Za-z0-9_]+" "${CMAKE_STATIC_LIBRARY_PREFIX}\\0"
+                       INSTALLED_LIBRARIES "${INSTALLED_LIBRARIES}")
+endif()
+
+configure_package_config_file(
+  ${CMAKE_CURRENT_SOURCE_DIR}/cmake/WebPConfig.cmake.in
+  ${CMAKE_CURRENT_BINARY_DIR}/WebPConfig.cmake
+  INSTALL_DESTINATION ${ConfigPackageLocation}
+  PATH_VARS CMAKE_INSTALL_INCLUDEDIR)
+
+# Install the generated CMake files.
+install(FILES "${CMAKE_CURRENT_BINARY_DIR}/WebPConfigVersion.cmake"
+              "${CMAKE_CURRENT_BINARY_DIR}/WebPConfig.cmake"
+        DESTINATION ${ConfigPackageLocation})
+
+# Install the man pages.
+set(MAN_PAGES
+    cwebp.1
+    dwebp.1
+    gif2webp.1
+    img2webp.1
+    vwebp.1
+    webpmux.1
+    webpinfo.1)
+set(EXEC_BUILDS
+    "CWEBP"
+    "DWEBP"
+    "GIF2WEBP"
+    "IMG2WEBP"
+    "VWEBP"
+    "WEBPMUX"
+    "WEBPINFO")
+list(LENGTH MAN_PAGES MAN_PAGES_LENGTH)
+math(EXPR MAN_PAGES_RANGE "${MAN_PAGES_LENGTH} - 1")
+
+foreach(I_MAN RANGE ${MAN_PAGES_RANGE})
+  list(GET EXEC_BUILDS ${I_MAN} EXEC_BUILD)
+  if(WEBP_BUILD_${EXEC_BUILD})
+    list(GET MAN_PAGES ${I_MAN} MAN_PAGE)
+    install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/man/${MAN_PAGE}
+            DESTINATION ${CMAKE_INSTALL_MANDIR}/man1 COMPONENT doc)
+  endif()
+endforeach()

CONTRIBUTING.md

@@ -0,0 +1,78 @@
+# How to Contribute
+
+We'd love to accept your patches and contributions to this project. There are
+just a few small guidelines you need to follow.
+
+## Contributor License Agreement
+
+Contributions to this project must be accompanied by a Contributor License
+Agreement. You (or your employer) retain the copyright to your contribution;
+this simply gives us permission to use and redistribute your contributions as
+part of the project. Head over to <https://cla.developers.google.com/> to see
+your current agreements on file or to sign a new one.
+
+You generally only need to submit a CLA once, so if you've already submitted one
+(even if it was for a different project), you probably don't need to do it
+again.
+
+## Code reviews
+
+All submissions, including submissions by project members, require review. We
+use a [Gerrit](https://www.gerritcodereview.com) instance hosted at
+https://chromium-review.googlesource.com for this purpose.
+
+## Sending patches
+
+The basic git workflow for modifying libwebp code and sending for review is:
+
+1.  Get the latest version of the repository locally:
+
+    ```sh
+    git clone https://chromium.googlesource.com/webm/libwebp && cd libwebp
+    ```
+
+2.  Copy the commit-msg script into ./git/hooks (this will add an ID to all of
+    your commits):
+
+    ```sh
+    curl -Lo .git/hooks/commit-msg https://chromium-review.googlesource.com/tools/hooks/commit-msg && chmod u+x .git/hooks/commit-msg
+    ```
+
+3.  Modify the local copy of libwebp. Make sure the code
+    [builds successfully](https://chromium.googlesource.com/webm/libwebp/+/HEAD/doc/building.md#cmake).
+
+4.  Choose a short and representative commit message:
+
+    ```sh
+    git commit -a -m "Set commit message here"
+    ```
+
+5.  Send the patch for review:
+
+    ```sh
+    git push https://chromium-review.googlesource.com/webm/libwebp HEAD:refs/for/main
+    ```
+
+    Go to https://chromium-review.googlesource.com to view your patch and
+    request a review from the maintainers.
+
+See the
+[WebM Project page](https://www.webmproject.org/code/contribute/submitting-patches/)
+for additional details.
+
+## Code Style
+
+The C code style is based on the
+[Google C++ Style Guide](https://google.github.io/styleguide/cppguide.html) and
+`clang-format --style=Google`, though this project doesn't use the tool to
+enforce the formatting.
+
+CMake files are formatted with
+[cmake-format](https://cmake-format.readthedocs.io/en/latest/). `cmake-format
+-i` can be used to format individual files, it will use the settings from
+`.cmake-format.py`.
+
+## Community Guidelines
+
+This project follows
+[Google's Open Source Community Guidelines](https://opensource.google.com/conduct/).

COPYING

@@ -0,0 +1,30 @@
+Copyright (c) 2010, Google Inc. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+  * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+  * Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in
+    the documentation and/or other materials provided with the
+    distribution.
+
+  * Neither the name of Google nor the names of its contributors may
+    be used to endorse or promote products derived from this software
+    without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+

Makefile.am

@@ -0,0 +1,9 @@
+ACLOCAL_AMFLAGS = -I m4
+SUBDIRS = sharpyuv src imageio man
+EXTRA_DIST = COPYING autogen.sh
+
+if BUILD_EXTRAS
+  SUBDIRS += extras
+endif
+
+SUBDIRS += examples

Makefile.vc

@@ -0,0 +1,528 @@
+#
+# Stem for static libs and DLLs
+#
+LIBWEBPDECODER_BASENAME = libwebpdecoder
+LIBWEBP_BASENAME = libwebp
+LIBWEBPMUX_BASENAME = libwebpmux
+LIBWEBPDEMUX_BASENAME = libwebpdemux
+LIBSHARPYUV_BASENAME = libsharpyuv
+
+!IFNDEF ARCH
+!IF ! [ cl 2>&1 | find "x86" > NUL ]
+ARCH = x86
+!ELSE IF ! [ cl 2>&1 | find "x64" > NUL ]
+ARCH = x64
+!ELSE IF ! [ cl 2>&1 | find "ARM" > NUL ]
+ARCH = ARM
+!ELSE
+!ERROR Unable to auto-detect toolchain architecture! \
+If cl.exe is in your PATH rerun nmake with ARCH=<arch>.
+!ENDIF
+!ENDIF
+
+!IF "$(ARCH)" == "x86"
+PLATFORM_LDFLAGS = /SAFESEH
+!ENDIF
+
+#############################################################
+## Nothing more to do below this line!
+
+NOLOGO     = /nologo
+CCNODBG    = cl.exe $(NOLOGO) /O2 /DNDEBUG
+CCDEBUG    = cl.exe $(NOLOGO) /Od /Zi /D_DEBUG /RTC1
+CFLAGS     = /I. /Isrc $(NOLOGO) /W3 /EHsc /c
+CFLAGS     = $(CFLAGS) /DWIN32 /D_CRT_SECURE_NO_WARNINGS /DWIN32_LEAN_AND_MEAN
+LDFLAGS    = /LARGEADDRESSAWARE /MANIFEST:EMBED /NXCOMPAT /DYNAMICBASE
+LDFLAGS    = $(LDFLAGS) $(PLATFORM_LDFLAGS)
+LNKDLL     = link.exe /DLL $(NOLOGO)
+LNKEXE     = link.exe $(NOLOGO)
+LNKLIB     = lib.exe $(NOLOGO)
+RCNODBG    = rc.exe $(NOLOGO) /l"0x0409"  # 0x409 = U.S. English
+RCDEBUG    = $(RCNODBG) /D_DEBUG
+
+!IF "$(ARCH)" == "ARM"
+CFLAGS = $(CFLAGS) /DWINAPI_FAMILY=WINAPI_FAMILY_PHONE_APP /DWEBP_USE_THREAD
+!ELSE
+CFLAGS = $(CFLAGS) /DHAVE_WINCODEC_H /DWEBP_USE_THREAD
+!ENDIF
+
+CFGSET     = FALSE
+!IF "$(OBJDIR)" == ""
+OUTDIR = ..\obj\
+!ELSE
+OUTDIR = $(OBJDIR)
+!ENDIF
+
+##############################################################
+# Runtime library configuration
+!IF "$(RTLIBCFG)" == "static"
+RTLIB  = /MT
+RTLIBD = /MTd
+!ELSE IF "$(RTLIBCFG)" == "legacy"
+RTLIBCFG = static
+RTLIB  = /MT
+RTLIBD = /MTd
+CFLAGS = $(CFLAGS) /GS- /arch:IA32
+!ELSE
+RTLIB   = /MD
+RTLIBD  = /MDd
+!ENDIF
+DIRBASE = $(OUTDIR)\$(CFG)\$(ARCH)
+DIROBJ = $(DIRBASE)\obj
+DIRLIB = $(DIRBASE)\lib
+DIRINC = $(DIRBASE)\include
+DIRBIN = $(DIRBASE)\bin
+LIBWEBP_PDBNAME = $(DIROBJ)\$(LIBWEBP_BASENAME).pdb
+OUTPUT_DIRS = $(DIRBIN) $(DIRINC) $(DIRLIB) \
+              $(DIROBJ)\dec \
+              $(DIROBJ)\demux \
+              $(DIROBJ)\dsp \
+              $(DIROBJ)\enc \
+              $(DIROBJ)\examples \
+              $(DIROBJ)\extras \
+              $(DIROBJ)\imageio \
+              $(DIROBJ)\mux \
+              $(DIROBJ)\sharpyuv \
+              $(DIROBJ)\utils \
+
+# Target configuration
+!IF "$(CFG)" == "release-static"
+CC             = $(CCNODBG)
+STATICLIBBUILD = TRUE
+!ELSE IF "$(CFG)" == "debug-static"
+CC             = $(CCDEBUG)
+RTLIB          = $(RTLIBD)
+STATICLIBBUILD = TRUE
+LIBWEBPDECODER_BASENAME = $(LIBWEBPDECODER_BASENAME)_debug
+LIBWEBP_BASENAME = $(LIBWEBP_BASENAME)_debug
+LIBWEBPMUX_BASENAME = $(LIBWEBPMUX_BASENAME)_debug
+LIBWEBPDEMUX_BASENAME = $(LIBWEBPDEMUX_BASENAME)_debug
+LIBSHARPYUV_BASENAME = $(LIBSHARPYUV_BASENAME)_debug
+!ELSE IF "$(CFG)" == "release-dynamic"
+CC        = $(CCNODBG)
+RC        = $(RCNODBG)
+DLLBUILD  = TRUE
+!ELSE IF "$(CFG)" == "debug-dynamic"
+CC        = $(CCDEBUG)
+RC        = $(RCDEBUG)
+RTLIB     = $(RTLIBD)
+DLLBUILD  = TRUE
+LIBWEBPDECODER_BASENAME = $(LIBWEBPDECODER_BASENAME)_debug
+LIBWEBP_BASENAME = $(LIBWEBP_BASENAME)_debug
+LIBWEBPMUX_BASENAME = $(LIBWEBPMUX_BASENAME)_debug
+LIBWEBPDEMUX_BASENAME = $(LIBWEBPDEMUX_BASENAME)_debug
+LIBSHARPYUV_BASENAME = $(LIBSHARPYUV_BASENAME)_debug
+!ENDIF
+
+!IF "$(STATICLIBBUILD)" == "TRUE"
+CC     = $(CC) $(RTLIB)
+CFGSET = TRUE
+LIBWEBPDECODER = $(DIRLIB)\$(LIBWEBPDECODER_BASENAME).lib
+LIBWEBP = $(DIRLIB)\$(LIBWEBP_BASENAME).lib
+LIBWEBPMUX = $(DIRLIB)\$(LIBWEBPMUX_BASENAME).lib
+LIBWEBPDEMUX = $(DIRLIB)\$(LIBWEBPDEMUX_BASENAME).lib
+LIBSHARPYUV = $(DIRLIB)\$(LIBSHARPYUV_BASENAME).lib
+!ELSE IF "$(DLLBUILD)" == "TRUE"
+CC     = $(CC) /I$(DIROBJ) $(RTLIB) /DWEBP_DLL
+LIBWEBPDECODER = $(DIRLIB)\$(LIBWEBPDECODER_BASENAME)_dll.lib
+LIBWEBP = $(DIRLIB)\$(LIBWEBP_BASENAME)_dll.lib
+LIBWEBPMUX = $(DIRLIB)\$(LIBWEBPMUX_BASENAME)_dll.lib
+LIBWEBPDEMUX = $(DIRLIB)\$(LIBWEBPDEMUX_BASENAME)_dll.lib
+LIBSHARPYUV = $(DIRLIB)\$(LIBSHARPYUV_BASENAME)_dll.lib
+LIBWEBP_PDBNAME = $(DIROBJ)\$(LIBWEBP_BASENAME)_dll.pdb
+CFGSET = TRUE
+!ENDIF
+
+!IF "$(UNICODE)" == "1"
+CFLAGS = $(CFLAGS) /D_UNICODE /DUNICODE
+!ENDIF
+
+#######################
+# Usage
+#
+!IF "$(CFGSET)" == "FALSE"
+!MESSAGE Usage: nmake /f Makefile.vc [CFG=<config>]
+!MESSAGE .          [OBJDIR=<path>] [RTLIBCFG=<rtlib>] [UNICODE=1] [<target>]
+!MESSAGE
+!MESSAGE where <config> is one of:
+!MESSAGE -  release-static                - release static library
+!MESSAGE -  debug-static                  - debug static library
+!MESSAGE -  release-dynamic               - release dynamic link library (DLL)
+!MESSAGE -  debug-dynamic                 - debug dynamic link library (DLL)
+!MESSAGE
+!MESSAGE <target> may be:
+!MESSAGE -  clean                         - perform a clean for CFG
+!MESSAGE -  experimental                  - build CFG with experimental
+!MESSAGE .                                  features enabled.
+!MESSAGE - (empty)                        - build libwebp-based targets for CFG
+!MESSAGE - all                            - build (de)mux-based targets for CFG
+!MESSAGE - gif2webp                       - requires libgif & >= VS2013
+!MESSAGE - anim_diff                      - requires libgif & >= VS2013
+!MESSAGE - anim_dump
+!MESSAGE
+!MESSAGE RTLIBCFG controls the runtime library linkage - 'static' or 'dynamic'.
+!MESSAGE   'legacy' will produce a Windows 2000 compatible library.
+!MESSAGE OBJDIR is the path where you like to build (obj, bins, etc.),
+!MESSAGE   defaults to ..\obj
+
+!IF "$(CFG)" != ""
+!MESSAGE
+!ERROR please choose a valid configuration instead of "$(CFG)"
+!ENDIF
+!ENDIF
+
+#######################
+# Rules
+#
+!IF "$(CFGSET)" == "TRUE"
+# A config was provided, so the library can be built.
+#
+
+SHARPYUV_OBJS = \
+    $(DIROBJ)\sharpyuv\sharpyuv.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_cpu.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_csp.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_dsp.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_gamma.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_neon.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_sse2.obj \
+
+DEC_OBJS = \
+    $(DIROBJ)\dec\alpha_dec.obj \
+    $(DIROBJ)\dec\buffer_dec.obj \
+    $(DIROBJ)\dec\frame_dec.obj \
+    $(DIROBJ)\dec\idec_dec.obj \
+    $(DIROBJ)\dec\io_dec.obj \
+    $(DIROBJ)\dec\quant_dec.obj \
+    $(DIROBJ)\dec\tree_dec.obj \
+    $(DIROBJ)\dec\vp8_dec.obj \
+    $(DIROBJ)\dec\vp8l_dec.obj \
+    $(DIROBJ)\dec\webp_dec.obj \
+
+DEMUX_OBJS = \
+    $(DIROBJ)\demux\anim_decode.obj \
+    $(DIROBJ)\demux\demux.obj \
+
+DSP_DEC_OBJS = \
+    $(DIROBJ)\dsp\alpha_processing.obj \
+    $(DIROBJ)\dsp\alpha_processing_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\alpha_processing_neon.obj \
+    $(DIROBJ)\dsp\alpha_processing_sse2.obj \
+    $(DIROBJ)\dsp\alpha_processing_sse41.obj \
+    $(DIROBJ)\dsp\cpu.obj \
+    $(DIROBJ)\dsp\dec.obj \
+    $(DIROBJ)\dsp\dec_clip_tables.obj \
+    $(DIROBJ)\dsp\dec_mips32.obj \
+    $(DIROBJ)\dsp\dec_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\dec_msa.obj \
+    $(DIROBJ)\dsp\dec_neon.obj \
+    $(DIROBJ)\dsp\dec_sse2.obj \
+    $(DIROBJ)\dsp\dec_sse41.obj \
+    $(DIROBJ)\dsp\filters.obj \
+    $(DIROBJ)\dsp\filters_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\filters_msa.obj \
+    $(DIROBJ)\dsp\filters_neon.obj \
+    $(DIROBJ)\dsp\filters_sse2.obj \
+    $(DIROBJ)\dsp\lossless.obj \
+    $(DIROBJ)\dsp\lossless_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\lossless_msa.obj \
+    $(DIROBJ)\dsp\lossless_neon.obj \
+    $(DIROBJ)\dsp\lossless_sse2.obj \
+    $(DIROBJ)\dsp\lossless_sse41.obj \
+    $(DIROBJ)\dsp\rescaler.obj \
+    $(DIROBJ)\dsp\rescaler_mips32.obj \
+    $(DIROBJ)\dsp\rescaler_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\rescaler_msa.obj \
+    $(DIROBJ)\dsp\rescaler_neon.obj \
+    $(DIROBJ)\dsp\rescaler_sse2.obj \
+    $(DIROBJ)\dsp\upsampling.obj \
+    $(DIROBJ)\dsp\upsampling_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\upsampling_msa.obj \
+    $(DIROBJ)\dsp\upsampling_neon.obj \
+    $(DIROBJ)\dsp\upsampling_sse2.obj \
+    $(DIROBJ)\dsp\upsampling_sse41.obj \
+    $(DIROBJ)\dsp\yuv.obj \
+    $(DIROBJ)\dsp\yuv_mips32.obj \
+    $(DIROBJ)\dsp\yuv_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\yuv_neon.obj \
+    $(DIROBJ)\dsp\yuv_sse2.obj \
+    $(DIROBJ)\dsp\yuv_sse41.obj \
+
+DSP_ENC_OBJS = \
+    $(DIROBJ)\dsp\cost.obj \
+    $(DIROBJ)\dsp\cost_mips32.obj \
+    $(DIROBJ)\dsp\cost_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\cost_neon.obj \
+    $(DIROBJ)\dsp\cost_sse2.obj \
+    $(DIROBJ)\dsp\enc.obj \
+    $(DIROBJ)\dsp\enc_mips32.obj \
+    $(DIROBJ)\dsp\enc_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\enc_msa.obj \
+    $(DIROBJ)\dsp\enc_neon.obj \
+    $(DIROBJ)\dsp\enc_sse2.obj \
+    $(DIROBJ)\dsp\enc_sse41.obj \
+    $(DIROBJ)\dsp\lossless_enc.obj \
+    $(DIROBJ)\dsp\lossless_enc_mips32.obj \
+    $(DIROBJ)\dsp\lossless_enc_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\lossless_enc_msa.obj \
+    $(DIROBJ)\dsp\lossless_enc_neon.obj \
+    $(DIROBJ)\dsp\lossless_enc_sse2.obj \
+    $(DIROBJ)\dsp\lossless_enc_sse41.obj \
+    $(DIROBJ)\dsp\ssim.obj \
+    $(DIROBJ)\dsp\ssim_sse2.obj \
+
+EX_ANIM_UTIL_OBJS = \
+    $(DIROBJ)\examples\anim_util.obj \
+
+IMAGEIO_DEC_OBJS = \
+    $(DIROBJ)\imageio\image_dec.obj \
+    $(DIROBJ)\imageio\jpegdec.obj \
+    $(DIROBJ)\imageio\metadata.obj \
+    $(DIROBJ)\imageio\pngdec.obj \
+    $(DIROBJ)\imageio\pnmdec.obj \
+    $(DIROBJ)\imageio\tiffdec.obj \
+    $(DIROBJ)\imageio\webpdec.obj \
+    $(DIROBJ)\imageio\wicdec.obj \
+
+IMAGEIO_ENC_OBJS = \
+    $(DIROBJ)\imageio\image_enc.obj \
+
+EX_GIF_DEC_OBJS = \
+    $(DIROBJ)\examples\gifdec.obj \
+
+EX_UTIL_OBJS = \
+    $(DIROBJ)\examples\example_util.obj \
+
+ENC_OBJS = \
+    $(DIROBJ)\enc\alpha_enc.obj \
+    $(DIROBJ)\enc\analysis_enc.obj \
+    $(DIROBJ)\enc\backward_references_cost_enc.obj \
+    $(DIROBJ)\enc\backward_references_enc.obj \
+    $(DIROBJ)\enc\config_enc.obj \
+    $(DIROBJ)\enc\cost_enc.obj \
+    $(DIROBJ)\enc\filter_enc.obj \
+    $(DIROBJ)\enc\frame_enc.obj \
+    $(DIROBJ)\enc\histogram_enc.obj \
+    $(DIROBJ)\enc\iterator_enc.obj \
+    $(DIROBJ)\enc\near_lossless_enc.obj \
+    $(DIROBJ)\enc\picture_enc.obj \
+    $(DIROBJ)\enc\picture_csp_enc.obj \
+    $(DIROBJ)\enc\picture_psnr_enc.obj \
+    $(DIROBJ)\enc\picture_rescale_enc.obj \
+    $(DIROBJ)\enc\picture_tools_enc.obj \
+    $(DIROBJ)\enc\predictor_enc.obj \
+    $(DIROBJ)\enc\quant_enc.obj \
+    $(DIROBJ)\enc\syntax_enc.obj \
+    $(DIROBJ)\enc\token_enc.obj \
+    $(DIROBJ)\enc\tree_enc.obj \
+    $(DIROBJ)\enc\vp8l_enc.obj \
+    $(DIROBJ)\enc\webp_enc.obj \
+
+EXTRAS_OBJS = \
+    $(DIROBJ)\extras\extras.obj \
+    $(DIROBJ)\extras\quality_estimate.obj \
+
+IMAGEIO_UTIL_OBJS = \
+    $(DIROBJ)\imageio\imageio_util.obj \
+
+MUX_OBJS = \
+    $(DIROBJ)\mux\anim_encode.obj \
+    $(DIROBJ)\mux\muxedit.obj \
+    $(DIROBJ)\mux\muxinternal.obj \
+    $(DIROBJ)\mux\muxread.obj \
+
+UTILS_DEC_OBJS = \
+    $(DIROBJ)\utils\bit_reader_utils.obj \
+    $(DIROBJ)\utils\color_cache_utils.obj \
+    $(DIROBJ)\utils\filters_utils.obj \
+    $(DIROBJ)\utils\huffman_utils.obj \
+    $(DIROBJ)\utils\palette.obj \
+    $(DIROBJ)\utils\quant_levels_dec_utils.obj \
+    $(DIROBJ)\utils\rescaler_utils.obj \
+    $(DIROBJ)\utils\random_utils.obj \
+    $(DIROBJ)\utils\thread_utils.obj \
+    $(DIROBJ)\utils\utils.obj \
+
+UTILS_ENC_OBJS = \
+    $(DIROBJ)\utils\bit_writer_utils.obj \
+    $(DIROBJ)\utils\huffman_encode_utils.obj \
+    $(DIROBJ)\utils\quant_levels_utils.obj \
+
+LIBWEBPDECODER_OBJS = $(DEC_OBJS) $(DSP_DEC_OBJS) $(UTILS_DEC_OBJS)
+LIBWEBP_OBJS = $(LIBWEBPDECODER_OBJS) $(ENC_OBJS) \
+               $(DSP_ENC_OBJS) $(UTILS_ENC_OBJS) $(DLL_OBJS)
+LIBWEBPMUX_OBJS = $(MUX_OBJS) $(LIBWEBPMUX_OBJS)
+LIBWEBPDEMUX_OBJS = $(DEMUX_OBJS) $(LIBWEBPDEMUX_OBJS)
+LIBSHARPYUV_OBJS = $(SHARPYUV_OBJS)
+
+OUT_LIBS = $(LIBWEBPDECODER) $(LIBWEBP) $(LIBSHARPYUV)
+!IF "$(ARCH)" == "ARM"
+ex: $(OUT_LIBS)
+all: ex
+!ELSE
+OUT_EXAMPLES = $(DIRBIN)\cwebp.exe $(DIRBIN)\dwebp.exe
+EXTRA_EXAMPLES = $(DIRBIN)\vwebp.exe $(DIRBIN)\webpmux.exe \
+                 $(DIRBIN)\img2webp.exe $(DIRBIN)\get_disto.exe \
+                 $(DIRBIN)\webp_quality.exe $(DIRBIN)\vwebp_sdl.exe \
+                 $(DIRBIN)\webpinfo.exe
+
+ex: $(OUT_LIBS) $(OUT_EXAMPLES)
+all: ex $(EXTRA_EXAMPLES)
+# NB: gif2webp.exe and anim_diff.exe are excluded from 'all' as libgif requires
+# C99 support which is only available from VS2013 onward.
+gif2webp: $(DIRBIN)\gif2webp.exe
+anim_diff: $(DIRBIN)\anim_diff.exe
+anim_dump: $(DIRBIN)\anim_dump.exe
+
+$(DIRBIN)\anim_diff.exe: $(DIROBJ)\examples\anim_diff.obj $(EX_ANIM_UTIL_OBJS)
+$(DIRBIN)\anim_diff.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\anim_diff.exe: $(EX_GIF_DEC_OBJS) $(LIBWEBPDEMUX) $(LIBWEBP)
+$(DIRBIN)\anim_dump.exe: $(DIROBJ)\examples\anim_dump.obj $(EX_ANIM_UTIL_OBJS)
+$(DIRBIN)\anim_dump.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\anim_dump.exe: $(EX_GIF_DEC_OBJS) $(LIBWEBPDEMUX) $(LIBWEBP)
+$(DIRBIN)\anim_dump.exe: $(IMAGEIO_ENC_OBJS)
+$(DIRBIN)\cwebp.exe: $(DIROBJ)\examples\cwebp.obj $(IMAGEIO_DEC_OBJS)
+$(DIRBIN)\cwebp.exe: $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\cwebp.exe: $(LIBWEBPDEMUX) $(LIBSHARPYUV)
+$(DIRBIN)\dwebp.exe: $(DIROBJ)\examples\dwebp.obj $(IMAGEIO_DEC_OBJS)
+$(DIRBIN)\dwebp.exe: $(IMAGEIO_ENC_OBJS)
+$(DIRBIN)\dwebp.exe: $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\dwebp.exe: $(LIBWEBPDEMUX)
+$(DIRBIN)\gif2webp.exe: $(DIROBJ)\examples\gif2webp.obj $(EX_GIF_DEC_OBJS)
+$(DIRBIN)\gif2webp.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS) $(LIBWEBPMUX)
+$(DIRBIN)\gif2webp.exe: $(LIBWEBP)
+$(DIRBIN)\vwebp.exe: $(DIROBJ)\examples\vwebp.obj $(EX_UTIL_OBJS)
+$(DIRBIN)\vwebp.exe: $(IMAGEIO_UTIL_OBJS) $(LIBWEBPDEMUX) $(LIBWEBP)
+$(DIRBIN)\vwebp_sdl.exe: $(DIROBJ)\extras\vwebp_sdl.obj
+$(DIRBIN)\vwebp_sdl.exe: $(DIROBJ)\extras\webp_to_sdl.obj
+$(DIRBIN)\vwebp_sdl.exe: $(IMAGEIO_UTIL_OBJS) $(LIBWEBP)
+$(DIRBIN)\webpmux.exe: $(DIROBJ)\examples\webpmux.obj $(LIBWEBPMUX)
+$(DIRBIN)\webpmux.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS) $(LIBWEBP)
+$(DIRBIN)\img2webp.exe: $(DIROBJ)\examples\img2webp.obj $(LIBWEBPMUX)
+$(DIRBIN)\img2webp.exe: $(IMAGEIO_DEC_OBJS)
+$(DIRBIN)\img2webp.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\img2webp.exe: $(LIBWEBPDEMUX) $(LIBWEBP) $(LIBSHARPYUV)
+$(DIRBIN)\get_disto.exe: $(DIROBJ)\extras\get_disto.obj
+$(DIRBIN)\get_disto.exe: $(IMAGEIO_DEC_OBJS) $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\get_disto.exe: $(LIBWEBPDEMUX) $(LIBWEBP)
+$(DIRBIN)\webp_quality.exe: $(DIROBJ)\extras\webp_quality.obj
+$(DIRBIN)\webp_quality.exe: $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\webp_quality.exe: $(EXTRAS_OBJS)
+# EXTRA_OBJS requires private symbols from dsp. Explicitly add those when
+# building libwebp as a dll.
+!IF "$(DLLBUILD)" == "TRUE"
+$(DIRBIN)\webp_quality.exe: $(DSP_DEC_OBJS)
+!ENDIF
+$(DIRBIN)\webp_quality.exe: $(LIBWEBP)
+$(DIRBIN)\webpinfo.exe: $(DIROBJ)\examples\webpinfo.obj
+$(DIRBIN)\webpinfo.exe: $(IMAGEIO_DEC_OBJS)
+$(DIRBIN)\webpinfo.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\webpinfo.exe: $(LIBWEBPDEMUX) $(LIBWEBP)
+
+$(OUT_EXAMPLES): $(EX_UTIL_OBJS) $(LIBWEBP)
+$(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS): $(OUTPUT_DIRS)
+$(IMAGEIO_DEC_OBJS) $(IMAGEIO_ENC_OBJS) $(EXTRAS_OBJS): $(OUTPUT_DIRS)
+!ENDIF  # ARCH == ARM
+
+$(LIBSHARPYUV): $(LIBSHARPYUV_OBJS)
+$(LIBWEBPDECODER): $(LIBWEBPDECODER_OBJS)
+$(LIBWEBP): $(LIBWEBP_OBJS) $(LIBSHARPYUV)
+$(LIBWEBPMUX): $(LIBWEBPMUX_OBJS)
+$(LIBWEBPDEMUX): $(LIBWEBPDEMUX_OBJS)
+
+$(LIBWEBP_OBJS) $(LIBWEBPMUX_OBJS) $(LIBWEBPDEMUX_OBJS) $(LIBSHARPYUV_OBJS): \
+    $(OUTPUT_DIRS)
+
+!IF "$(DLLBUILD)" == "TRUE"
+{$(DIROBJ)}.c{$(DIROBJ)}.obj:
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$@  $<
+
+{src}.rc{$(DIROBJ)}.res:
+	$(RC) /fo$@ $<
+{src\demux}.rc{$(DIROBJ)\demux}.res:
+	$(RC) /fo$@ $<
+{src\mux}.rc{$(DIROBJ)\mux}.res:
+	$(RC) /fo$@ $<
+{sharpyuv}.rc{$(DIROBJ)\sharpyuv}.res:
+	$(RC) /fo$@ $<
+
+$(LIBSHARPYUV): $(DIROBJ)\sharpyuv\$(LIBSHARPYUV_BASENAME:_debug=).res
+$(LIBWEBP): $(LIBSHARPYUV) $(DIROBJ)\$(LIBWEBP_BASENAME:_debug=).res
+$(LIBWEBPDECODER): $(DIROBJ)\$(LIBWEBPDECODER_BASENAME:_debug=).res
+$(LIBWEBPMUX): $(LIBWEBP) $(DIROBJ)\mux\$(LIBWEBPMUX_BASENAME:_debug=).res
+$(LIBWEBPDEMUX): $(LIBWEBP) $(DIROBJ)\demux\$(LIBWEBPDEMUX_BASENAME:_debug=).res
+
+$(LIBWEBPDECODER) $(LIBWEBP) $(LIBWEBPMUX) $(LIBWEBPDEMUX) $(LIBSHARPYUV):
+	$(LNKDLL) /out:$(DIRBIN)\$(@B:_dll=.dll) /implib:$@ $(LFLAGS) $**
+	-xcopy $(DIROBJ)\*.pdb $(DIRLIB) /y
+!ELSE
+$(LIBWEBPDECODER) $(LIBWEBP) $(LIBWEBPMUX) $(LIBWEBPDEMUX) $(LIBSHARPYUV):
+	$(LNKLIB) /out:$@ $**
+	-xcopy $(DIROBJ)\*.pdb $(DIRLIB) /y
+!ENDIF
+
+$(OUTPUT_DIRS):
+	@if not exist "$(@)" mkdir "$(@)"
+
+.SUFFIXES: .c .obj .res .exe
+# File-specific flag builds. Note batch rules take precedence over wildcards,
+# so for now name each file individually.
+$(DIROBJ)\examples\anim_diff.obj: examples\anim_diff.c
+	$(CC) $(CFLAGS) /DWEBP_HAVE_GIF /Fd$(LIBWEBP_PDBNAME) \
+	  /Fo$(DIROBJ)\examples\ examples\$(@B).c
+$(DIROBJ)\examples\anim_dump.obj: examples\anim_dump.c
+	$(CC) $(CFLAGS) /DWEBP_HAVE_GIF /Fd$(LIBWEBP_PDBNAME) \
+	  /Fo$(DIROBJ)\examples\ examples\$(@B).c
+$(DIROBJ)\examples\anim_util.obj: examples\anim_util.c
+	$(CC) $(CFLAGS) /DWEBP_HAVE_GIF /Fd$(LIBWEBP_PDBNAME) \
+	  /Fo$(DIROBJ)\examples\ examples\$(@B).c
+$(DIROBJ)\examples\gif2webp.obj: examples\gif2webp.c
+	$(CC) $(CFLAGS) /DWEBP_HAVE_GIF /Fd$(LIBWEBP_PDBNAME) \
+	  /Fo$(DIROBJ)\examples\ examples\$(@B).c
+$(DIROBJ)\examples\gifdec.obj: examples\gifdec.c
+	$(CC) $(CFLAGS) /DWEBP_HAVE_GIF /Fd$(LIBWEBP_PDBNAME) \
+	  /Fo$(DIROBJ)\examples\ examples\$(@B).c
+# Batch rules
+{examples}.c{$(DIROBJ)\examples}.obj::
+	$(CC) $(CFLAGS) /Fd$(DIROBJ)\examples\ /Fo$(DIROBJ)\examples\ $<
+{extras}.c{$(DIROBJ)\extras}.obj::
+	$(CC) $(CFLAGS) /Fd$(DIROBJ)\extras\ /Fo$(DIROBJ)\extras\ $<
+{imageio}.c{$(DIROBJ)\imageio}.obj::
+	$(CC) $(CFLAGS) /Fd$(DIROBJ)\imageio\ /Fo$(DIROBJ)\imageio\ $<
+{sharpyuv}.c{$(DIROBJ)\sharpyuv}.obj::
+	$(CC) $(CFLAGS) /Fd$(DIROBJ)\sharpyuv\ /Fo$(DIROBJ)\sharpyuv\ $<
+{src\dec}.c{$(DIROBJ)\dec}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\dec\ $<
+{src\demux}.c{$(DIROBJ)\demux}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\demux\ $<
+{src\dsp}.c{$(DIROBJ)\dsp}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\dsp\ $<
+{src\enc}.c{$(DIROBJ)\enc}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\enc\ $<
+{src\mux}.c{$(DIROBJ)\mux}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\mux\ $<
+{src\utils}.c{$(DIROBJ)\utils}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\utils\ $<
+
+LNKLIBS     = ole32.lib windowscodecs.lib shlwapi.lib
+!IF "$(UNICODE)" == "1"
+LNKLIBS     = $(LNKLIBS) Shell32.lib
+!ENDIF
+
+{$(DIROBJ)\examples}.obj{$(DIRBIN)}.exe:
+	$(LNKEXE) $(LDFLAGS) /OUT:$@ $** $(LNKLIBS)
+
+{$(DIROBJ)\extras}.obj{$(DIRBIN)}.exe:
+	$(LNKEXE) $(LDFLAGS) /OUT:$@ $** $(LNKLIBS)
+
+clean::
+	@-erase /s $(DIROBJ)\*.dll 2> NUL
+	@-erase /s $(DIROBJ)\*.exp 2> NUL
+	@-erase /s $(DIROBJ)\*.idb 2> NUL
+	@-erase /s $(DIROBJ)\*.lib 2> NUL
+	@-erase /s $(DIROBJ)\*.obj 2> NUL
+	@-erase /s $(DIROBJ)\*.pch 2> NUL
+	@-erase /s $(DIROBJ)\*.pdb 2> NUL
+	@-erase /s $(DIROBJ)\*.res 2> NUL
+
+!ENDIF  # End of case where a config was provided.

NEWS

@@ -0,0 +1,311 @@
+- 6/23/2023: version 1.3.1
+  This is a binary compatible release.
+  * security fixes for lossless encoder (#603, chromium: #1420107, #1455619,
+    CVE-2023-1999)
+  * improve error reporting through WebPPicture error codes
+  * fix upsampling for RGB565 and RGBA4444 in NEON builds
+  * img2webp: add -sharp_yuv & -near_lossless
+  * Windows builds:
+    - fix compatibility with clang-cl (#607)
+    - improve Arm64 performance with cl.exe
+    - add Arm64EC support
+  * fix webp_js with emcc >= 3.1.27 (stack size change, #614)
+  * CMake fixes (#592, #610, #612)
+  * further updates to the container and lossless bitstream docs (#581, #611)
+
+- 12/16/2022: version 1.3.0
+  This is a binary compatible release.
+  * add libsharpyuv, which exposes -sharp_yuv/config.use_sharp_yuv
+    functionality to other libraries; libwebp now depends on this library
+  * major updates to the container and lossless bitstream docs (#448, #546,
+    #551)
+  * miscellaneous warning, bug & build fixes (#576, #583, #584)
+
+- 8/4/2022: version 1.2.4
+  This is a binary compatible release.
+  * restore CMake libwebpmux target name for compatibility with 1.2.2 (#575)
+  * fix lossless crunch mode encoding with WEBP_REDUCE_SIZE
+    (chromium: #1345547, #1345595, #1345772, #1345804)
+
+- 6/30/2022: version 1.2.3
+  This is a binary compatible release.
+  * security fix for lossless encoder (#565, chromium:1313709)
+  * improved progress granularity in WebPReportProgress() when using lossless
+  * improved precision in Sharp YUV (-sharp_yuv) conversion
+  * many corrections to webp-lossless-bitstream-spec.txt (#551)
+  * crash/leak fixes on error/OOM and other bug fixes (#558, #563, #569, #573)
+
+- 1/11/2022: version 1.2.2
+  This is a binary compatible release.
+  * webpmux: add "-set bgcolor A,R,G,B"
+  * add ARM64 NEON support for MSVC builds (#539)
+  * fix duplicate include error in Xcode when using multiple XCFrameworks in a
+    project (#542)
+  * doc updates and bug fixes (#538, #544, #548, #550)
+
+- 7/20/2021: version 1.2.1
+  This is a binary compatible release.
+  * minor lossless encoder improvements and x86 color conversion speed up
+  * add ARM64 simulator support to xcframeworkbuild.sh (#510)
+  * further security related hardening in libwebp & examples
+    (issues: #497, #508, #518)
+    (chromium: #1196480, #1196773, #1196775, #1196777, #1196778, #1196850)
+    (oss-fuzz: #28658, #28978)
+  * toolchain updates and bug fixes (#498, #501, #502, #504, #505, #506, #509,
+                                     #533)
+  * use more inclusive language within the source (#507)
+
+- 12/23/2020: version 1.2.0
+  * API changes:
+    - libwebp:
+      encode.h: add a qmin / qmax range for quality factor (cwebp adds -qrange)
+  * lossless encoder improvements
+  * SIMD support for Wasm builds
+  * add xcframeworkbuild.sh, supports Mac Catalyst builds
+  * import fuzzers from oss-fuzz & chromium (#409)
+  * webpmux: add an '-set loop <value>' option (#494)
+  * toolchain updates and bug fixes (#449, #463, #470, #475, #477, #478, #479,
+    #488, #491)
+
+- 12/18/2019: version 1.1.0
+  * API changes:
+    - libwebp:
+      WebPMalloc (issue #442)
+    - extras:
+      WebPUnmultiplyARGB
+  * alpha decode fix (issue #439)
+  * toolchain updates and bug fixes
+    (chromium: #1026858, #1027136, #1027409, #1028620, #1028716, #995200)
+    (oss-fuzz: #19430, #19447)
+
+- 7/4/2019: version 1.0.3
+  This is a binary compatible release.
+  * resize fixes for Nx1 sizes and the addition of non-opaque alpha values for
+    odd sizes (issues #418, #434)
+  * lossless encode/decode performance improvements
+  * lossy compression performance improvement at low quality levels with flat
+    content (issue #432)
+  * python swig files updated to support python 3
+  Tool updates:
+    vwebp will now preserve the aspect ratio of images that exceed monitor
+    resolution by scaling the image to fit (issue #433)
+
+- 1/14/2019: version 1.0.2
+  This is a binary compatible release.
+  * (Windows) unicode file support in the tools (linux and mac already had
+    support, issue #398)
+  * lossless encoder speedups
+  * lossy encoder speedup on ARM
+  * lossless multi-threaded security fix (chromium:917029)
+
+- 11/2/2018: version 1.0.1
+  This is a binary compatible release.
+  * lossless encoder speedups
+  * big-endian fix for alpha decoding (issue #393)
+  * gif2webp fix for loop count=65535 transcode (issue #382)
+  * further security related hardening in libwebp & libwebpmux
+    (issues #383, #385, #386, #387, #388, #391)
+    (oss-fuzz #9099, #9100, #9105, #9106, #9111, #9112, #9119, #9123, #9170,
+              #9178, #9179, #9183, #9186, #9191, #9364, #9417, #9496, #10349,
+              #10423, #10634, #10700, #10838, #10922, #11021, #11088, #11152)
+  * miscellaneous bug & build fixes (issues #381, #394, #396, #397, #400)
+
+- 4/2/2018: version 1.0.0
+  This is a binary compatible release.
+  * lossy encoder improvements to avoid chroma shifts in various circumstances
+    (issues #308, #340)
+  * big-endian fixes for decode, RGBA import and WebPPictureDistortion
+  Tool updates:
+    gifwebp, anim_diff - default duration behavior (<= 10ms) changed to match
+                         web browsers, transcoding tools (issue #379)
+    img2webp, webpmux - allow options to be passed in via a file (issue #355)
+
+- 11/24/2017: version 0.6.1
+  This is a binary compatible release.
+  * lossless performance and compression improvements + a new 'cruncher' mode
+    (-m 6 -q 100)
+  * ARM performance improvements with clang (15-20% w/ndk r15c, issue #339)
+  * webp-js: emscripten/webassembly based javascript decoder
+  * miscellaneous bug & build fixes (issue #329, #332, #343, #353, #360, #361,
+    #363)
+  Tool updates / additions:
+    added webpinfo - prints file format information (issue #330)
+    gif2webp - loop behavior modified to match Chrome M63+ (crbug.com/649264);
+               '-loop_compatibility' can be used for the old behavior
+
+- 1/26/2017: version 0.6.0
+  * lossless performance and compression improvements
+  * miscellaneous performance improvements (SSE2, NEON, MSA)
+  * webpmux gained a -duration option allowing for frame timing modification
+  * new img2webp utility allowing a sequence of images to be converted to
+    animated webp
+  * API changes:
+    - libwebp:
+      WebPPictureSharpARGBToYUVA
+      WebPPlaneDistortion
+    - libwebpmux / gif2webp:
+      WebPAnimEncoderOptions: kmax <= 0 now disables keyframes, kmax == 1
+                              forces all keyframes. See mux.h and the gif2webp
+                              manpage for details.
+
+- 12/13/2016: version 0.5.2
+  This is a binary compatible release.
+  This release covers CVE-2016-8888 and CVE-2016-9085.
+  * further security related hardening in the tools; fixes to
+    gif2webp/AnimEncoder (issues #310, #314, #316, #322), cwebp/libwebp (issue
+    #312)
+  * full libwebp (encoder & decoder) iOS framework; libwebpdecoder
+    WebP.framework renamed to WebPDecoder.framework (issue #307)
+  * CMake support for Android Studio (2.2)
+  * miscellaneous build related fixes (issue #306, #313)
+  * miscellaneous documentation improvements (issue #225)
+  * minor lossy encoder fixes and improvements
+
+- 6/14/2016: version 0.5.1
+  This is a binary compatible release.
+  * miscellaneous bug fixes (issues #280, #289)
+  * reverted alpha plane encoding with color cache for compatibility with
+    libwebp 0.4.0->0.4.3 (issues #291, #298)
+  * lossless encoding performance improvements
+  * memory reduction in both lossless encoding and decoding
+  * force mux output to be in the extended format (VP8X) when undefined chunks
+    are present (issue #294)
+  * gradle, cmake build support
+  * workaround for compiler bug causing 64-bit decode failures on android
+    devices using clang-3.8 in the r11c NDK
+  * various WebPAnimEncoder improvements
+
+- 12/17/2015: version 0.5.0
+  * miscellaneous bug & build fixes (issues #234, #258, #274, #275, #278)
+  * encoder & decoder speed-ups on x86/ARM/MIPS for lossy & lossless
+    - note! YUV->RGB conversion was sped-up, but the results will be slightly
+      different from previous releases
+  * various lossless encoder improvements
+  * gif2webp improvements, -min_size option added
+  * tools fully support input from stdin and output to stdout (issue #168)
+  * New WebPAnimEncoder API for creating animations
+  * New WebPAnimDecoder API for decoding animations
+  * other API changes:
+    - libwebp:
+      WebPPictureSmartARGBToYUVA() (-pre 4 in cwebp)
+      WebPConfig::exact (-exact in cwebp; -alpha_cleanup is now the default)
+      WebPConfig::near_lossless (-near_lossless in cwebp)
+      WebPFree() (free'ing webp allocated memory in other languages)
+      WebPConfigLosslessPreset()
+      WebPMemoryWriterClear()
+    - libwebpdemux: removed experimental fragment related fields and functions
+    - libwebpmux: WebPMuxSetCanvasSize()
+  * new libwebpextras library with some uncommon import functions:
+    WebPImportGray/WebPImportRGB565/WebPImportRGB4444
+
+- 10/15/15: version 0.4.4
+  This is a binary compatible release.
+  * rescaling out-of-bounds read fix (issue #254)
+  * various build fixes and improvements (issues #253, #259, #262, #267, #268)
+  * container documentation update
+  * gif2webp transparency fix (issue #245)
+
+- 3/3/15: version 0.4.3
+  This is a binary compatible release.
+  * Android / gcc / iOS / MSVS build fixes and improvements
+  * lossless decode fix (issue #239 -- since 0.4.0)
+  * documentation / vwebp updates for animation
+  * multi-threading fix (issue #234)
+
+- 10/13/14: version 0.4.2
+  This is a binary compatible release.
+  * Android / gcc build fixes
+  * (Windows) fix reading from stdin and writing to stdout
+  * gif2webp: miscellaneous fixes
+  * fix 'alpha-leak' with lossy compression (issue #220)
+  * the lossless bitstream spec has been amended to reflect the current code
+
+- 7/24/14: version 0.4.1
+  This is a binary compatible release.
+  * AArch64 (arm64) & MIPS support/optimizations
+  * NEON assembly additions:
+    - ~25% faster lossy decode / encode (-m 4)
+    - ~10% faster lossless decode
+    - ~5-10% faster lossless encode (-m 3/4)
+  * dwebp/vwebp can read from stdin
+  * cwebp/gif2webp can write to stdout
+  * cwebp can read webp files; useful if storing sources as webp lossless
+
+- 12/19/13: version 0.4.0
+  * improved gif2webp tool
+  * numerous fixes, compression improvement and speed-up
+  * dither option added to decoder (dwebp -dither 50 ...)
+  * improved multi-threaded modes (-mt option)
+  * improved filtering strength determination
+  * New function: WebPMuxGetCanvasSize
+  * BMP and TIFF format output added to 'dwebp'
+  * Significant memory reduction for decoding lossy images with alpha.
+  * Intertwined decoding of RGB and alpha for a shorter
+    time-to-first-decoded-pixel.
+  * WebPIterator has a new member 'has_alpha' denoting whether the frame
+    contains transparency.
+  * Container spec amended with new 'blending method' for animation.
+
+- 6/13/13: version 0.3.1
+  This is a binary compatible release.
+  * Add incremental decoding support for images containing ALPH and ICCP chunks.
+  * Python bindings via swig for the simple encode/decode interfaces similar to
+    Java.
+
+- 3/20/13: version 0.3.0
+  This is a binary compatible release.
+  * WebPINewRGB/WebPINewYUVA accept being passed a NULL output buffer
+    and will perform auto-allocation.
+  * default filter option is now '-strong -f 60'
+  * encoding speed-up for lossy methods 3 to 6
+  * alpha encoding can be done in parallel to lossy using 'cwebp -mt ...'
+  * color profile, metadata (XMP/EXIF) and animation support finalized in the
+    container.
+  * various NEON assembly additions
+  Tool updates / additions:
+    * gif2webp added
+    * vwebp given color profile & animation support
+    * cwebp can preserve color profile / metadata with '-metadata'
+
+- 10/30/12: version 0.2.1
+  * Various security related fixes
+  * cwebp.exe: fix import errors on Windows XP
+  * enable DLL builds for mingw targets
+
+- 8/3/12: version 0.2.0
+  * Add support for ARGB -> YUVA conversion for lossless decoder
+    New functions: WebPINewYUVA, WebPIDecGetYUVA
+  * Add stats for lossless and alpha encoding
+  * Security related hardening: allocation and size checks
+  * Add PAM output support to dwebp
+
+- 7/19/12: version 0.1.99
+  * This is a pre-release of 0.2.0, not an rc to allow for further
+    incompatible changes based on user feedback.
+  * Alpha channel encode/decode support.
+  * Lossless encoder/decoder.
+  * Add TIFF input support to cwebp.
+  Incompatible changes:
+    * The encode ABI has been modified to support alpha encoding.
+    * Deprecated function WebPINew() has been removed.
+    * Decode function signatures have changed to consistently use size_t over
+      int/uint32_t.
+    * decode_vp8.h is no longer installed system-wide.
+    * cwebp will encode the alpha channel if present.
+
+- 9/19/11: version 0.1.3
+  * Advanced decoding APIs.
+  * On-the-fly cropping and rescaling of images.
+  * SSE2 instructions for decoding performance optimizations on x86 based
+    platforms.
+  * Support Multi-threaded decoding.
+  * 40% improvement in Decoding performance.
+  * Add support for RGB565, RGBA4444 & ARGB image colorspace.
+  * Better handling of large picture encoding.
+
+- 3/25/11: version 0.1.2
+  * Incremental decoding: picture can be decoded byte-by-byte if needs be.
+  * lot of bug-fixes, consolidation and stabilization
+
+- 2/23/11: initial release of version 0.1, with the new encoder
+- 9/30/10: initial release version with only the lightweight decoder

PATENTS

@@ -0,0 +1,23 @@
+Additional IP Rights Grant (Patents)
+------------------------------------
+
+"These implementations" means the copyrightable works that implement the WebM
+codecs distributed by Google as part of the WebM Project.
+
+Google hereby grants to you a perpetual, worldwide, non-exclusive, no-charge,
+royalty-free, irrevocable (except as stated in this section) patent license to
+make, have made, use, offer to sell, sell, import, transfer, and otherwise
+run, modify and propagate the contents of these implementations of WebM, where
+such license applies only to those patent claims, both currently owned by
+Google and acquired in the future, licensable by Google that are necessarily
+infringed by these implementations of WebM. This grant does not include claims
+that would be infringed only as a consequence of further modification of these
+implementations. If you or your agent or exclusive licensee institute or order
+or agree to the institution of patent litigation or any other patent
+enforcement activity against any entity (including a cross-claim or
+counterclaim in a lawsuit) alleging that any of these implementations of WebM
+or any code incorporated within any of these implementations of WebM
+constitute direct or contributory patent infringement, or inducement of
+patent infringement, then any patent rights granted to you under this License
+for these implementations of WebM shall terminate as of the date such
+litigation is filed.

PRESUBMIT.py

@@ -0,0 +1,245 @@
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+"""Top-level presubmit script for libwebp.
+
+See https://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
+details on the presubmit API built into depot_tools.
+"""
+
+import re
+import subprocess2
+
+USE_PYTHON3 = True
+_BASH_INDENTATION = "2"
+_GIT_COMMIT_SUBJECT_LENGTH = 65
+_INCLUDE_BASH_FILES_ONLY = [r".*\.sh$"]
+_INCLUDE_MAN_FILES_ONLY = [r"man/.+\.1$"]
+_INCLUDE_SOURCE_FILES_ONLY = [r".*\.[ch]$"]
+_LIBWEBP_MAX_LINE_LENGTH = 80
+
+
+def _CheckCommitSubjectLength(input_api, output_api):
+  """Ensures commit's subject length is no longer than 65 chars."""
+  name = "git-commit subject"
+  cmd = ["git", "log", "-1", "--pretty=%s"]
+  start = input_api.time.time()
+  proc = subprocess2.Popen(
+      cmd,
+      stderr=subprocess2.PIPE,
+      stdout=subprocess2.PIPE,
+      universal_newlines=True)
+
+  stdout, _ = proc.communicate()
+  duration = input_api.time.time() - start
+
+  if not re.match(r"^Revert",
+                  stdout) and (len(stdout) - 1) > _GIT_COMMIT_SUBJECT_LENGTH:
+    failure_msg = (
+        "The commit subject: %s is too long (%d chars)\n"
+        "Try to keep this to 50 or less (up to 65 is permitted for "
+        "non-reverts).\n"
+        "https://www.git-scm.com/book/en/v2/Distributed-Git-Contributing-to-a-"
+        "Project#_commit_guidelines") % (stdout, len(stdout) - 1)
+    return output_api.PresubmitError("%s\n (%4.2fs) failed\n%s" %
+                                     (name, duration, failure_msg))
+
+  return output_api.PresubmitResult("%s\n (%4.2fs) success" % (name, duration))
+
+
+def _CheckDuplicateFiles(input_api, output_api):
+  """Ensures there are not repeated filenames."""
+  all_files = []
+  for f in input_api.change.AllFiles():
+    for include_file in _INCLUDE_SOURCE_FILES_ONLY:
+      if re.match(include_file, f):
+        all_files.append(f)
+        break
+
+  basename_to_path = {}
+  for f in all_files:
+    basename_file = input_api.basename(f)
+    if basename_file in basename_to_path:
+      basename_to_path[basename_file].append(f)
+    else:
+      basename_to_path[basename_file] = [f]
+
+  dupes = []
+  for files in basename_to_path.values():
+    if len(files) > 1:
+      dupes.extend(files)
+
+  if dupes:
+    return output_api.PresubmitError(
+        "Duplicate source files, rebase or rename some to make them unique:\n%s"
+        % dupes)
+  return output_api.PresubmitResult("No duplicates, success\n")
+
+
+def _GetFilesToSkip(input_api):
+  return list(input_api.DEFAULT_FILES_TO_SKIP) + [
+      r"swig/.*\.py$",
+      r"\.pylintrc$",
+  ]
+
+
+def _RunManCmd(input_api, output_api, man_file):
+  """man command wrapper."""
+  cmd = ["man", "--warnings", "-EUTF-8", "-l", "-Tutf8", "-Z", man_file]
+  name = "Check %s file." % man_file
+  start = input_api.time.time()
+  output, _ = subprocess2.communicate(
+      cmd, stdout=None, stderr=subprocess2.PIPE, universal_newlines=True)
+  duration = input_api.time.time() - start
+  if output[1]:
+    return output_api.PresubmitError("%s\n%s (%4.2fs) failed\n%s" %
+                                     (name, " ".join(cmd), duration, output[1]))
+  return output_api.PresubmitResult("%s\n%s (%4.2fs)\n" %
+                                    (name, " ".join(cmd), duration))
+
+
+def _RunShellCheckCmd(input_api, output_api, bash_file):
+  """shellcheck command wrapper."""
+  cmd = ["shellcheck", "-x", "-oall", "-sbash", bash_file]
+  name = "Check %s file." % bash_file
+  start = input_api.time.time()
+  output, rc = subprocess2.communicate(
+      cmd, stdout=None, stderr=subprocess2.PIPE, universal_newlines=True)
+  duration = input_api.time.time() - start
+  if rc == 0:
+    return output_api.PresubmitResult("%s\n%s (%4.2fs)\n" %
+                                      (name, " ".join(cmd), duration))
+  return output_api.PresubmitError("%s\n%s (%4.2fs) failed\n%s" %
+                                   (name, " ".join(cmd), duration, output[1]))
+
+
+def _RunShfmtCheckCmd(input_api, output_api, bash_file):
+  """shfmt command wrapper."""
+  cmd = [
+      "shfmt", "-i", _BASH_INDENTATION, "-bn", "-ci", "-sr", "-kp", "-d",
+      bash_file
+  ]
+  name = "Check %s file." % bash_file
+  start = input_api.time.time()
+  output, rc = subprocess2.communicate(
+      cmd, stdout=None, stderr=subprocess2.PIPE, universal_newlines=True)
+  duration = input_api.time.time() - start
+  if rc == 0:
+    return output_api.PresubmitResult("%s\n%s (%4.2fs)\n" %
+                                      (name, " ".join(cmd), duration))
+  return output_api.PresubmitError("%s\n%s (%4.2fs) failed\n%s" %
+                                   (name, " ".join(cmd), duration, output[1]))
+
+
+def _RunCmdOnCheckedFiles(input_api, output_api, run_cmd, files_to_check):
+  """Ensure that libwebp/ files are clean."""
+  file_filter = lambda x: input_api.FilterSourceFile(
+      x, files_to_check=files_to_check, files_to_skip=None)
+
+  affected_files = input_api.change.AffectedFiles(file_filter=file_filter)
+  results = [
+      run_cmd(input_api, output_api, f.AbsoluteLocalPath())
+      for f in affected_files
+  ]
+  return results
+
+
+def _CommonChecks(input_api, output_api):
+  """Ensures this patch does not have trailing spaces, extra EOLs,
+     or long lines.
+  """
+  results = []
+  results.extend(
+      input_api.canned_checks.CheckChangeHasNoCrAndHasOnlyOneEol(
+          input_api, output_api))
+  results.extend(
+      input_api.canned_checks.CheckChangeHasNoTabs(input_api, output_api))
+  results.extend(
+      input_api.canned_checks.CheckChangeHasNoStrayWhitespace(
+          input_api, output_api))
+  results.append(_CheckCommitSubjectLength(input_api, output_api))
+  results.append(_CheckDuplicateFiles(input_api, output_api))
+
+  source_file_filter = lambda x: input_api.FilterSourceFile(
+      x, files_to_skip=_GetFilesToSkip(input_api))
+  results.extend(
+      input_api.canned_checks.CheckLongLines(
+          input_api,
+          output_api,
+          maxlen=_LIBWEBP_MAX_LINE_LENGTH,
+          source_file_filter=source_file_filter))
+
+  results.extend(
+      input_api.canned_checks.CheckPatchFormatted(
+          input_api,
+          output_api,
+          check_clang_format=False,
+          check_python=True,
+          result_factory=output_api.PresubmitError))
+  results.extend(
+      _RunCmdOnCheckedFiles(input_api, output_api, _RunManCmd,
+                            _INCLUDE_MAN_FILES_ONLY))
+  # Run pylint.
+  results.extend(
+      input_api.canned_checks.RunPylint(
+          input_api,
+          output_api,
+          files_to_skip=_GetFilesToSkip(input_api),
+          pylintrc=".pylintrc",
+          version="2.7"))
+
+  # Binaries shellcheck and shfmt are not installed in depot_tools.
+  # Installation is needed
+  try:
+    subprocess2.communicate(["shellcheck", "--version"])
+    results.extend(
+        _RunCmdOnCheckedFiles(input_api, output_api, _RunShellCheckCmd,
+                              _INCLUDE_BASH_FILES_ONLY))
+    print("shfmt")
+    subprocess2.communicate(["shfmt", "-version"])
+    results.extend(
+        _RunCmdOnCheckedFiles(input_api, output_api, _RunShfmtCheckCmd,
+                              _INCLUDE_BASH_FILES_ONLY))
+  except OSError as os_error:
+    results.append(
+        output_api.PresubmitPromptWarning(
+            "%s\nPlease install missing binaries locally." % os_error.args[0]))
+  return results
+
+
+def CheckChangeOnUpload(input_api, output_api):
+  results = []
+  results.extend(_CommonChecks(input_api, output_api))
+  return results
+
+
+def CheckChangeOnCommit(input_api, output_api):
+  results = []
+  results.extend(_CommonChecks(input_api, output_api))
+  return results

README.md

@@ -0,0 +1,53 @@
+# WebP Codec
+
+```
+      __   __  ____  ____  ____
+     /  \\/  \/  _ \/  _ )/  _ \
+     \       /   __/  _  \   __/
+      \__\__/\____/\_____/__/ ____  ___
+            / _/ /    \    \ /  _ \/ _/
+           /  \_/   / /   \ \   __/  \__
+           \____/____/\_____/_____/____/v1.3.1
+```
+
+WebP codec is a library to encode and decode images in WebP format. This package
+contains the library that can be used in other programs to add WebP support, as
+well as the command line tools 'cwebp' and 'dwebp' to compress and decompress
+images respectively.
+
+See https://developers.google.com/speed/webp for details on the image format.
+
+The latest source tree is available at
+https://chromium.googlesource.com/webm/libwebp
+
+It is released under the same license as the WebM project. See
+https://www.webmproject.org/license/software/ or the "COPYING" file for details.
+An additional intellectual property rights grant can be found in the file
+PATENTS.
+
+## Building
+
+See the [building documentation](doc/building.md).
+
+## Encoding and Decoding Tools
+
+The examples/ directory contains tools to encode and decode images and
+animations, view information about WebP images, and more. See the
+[tools documentation](doc/tools.md).
+
+## APIs
+
+See the [APIs documentation](doc/api.md), and API usage examples in the
+`examples/` directory.
+
+## Bugs
+
+Please report all bugs to the issue tracker: https://bugs.chromium.org/p/webp
+
+Patches welcome! See [how to contribute](CONTRIBUTING.md).
+
+## Discuss
+
+Email: webp-discuss@webmproject.org
+
+Web: https://groups.google.com/a/webmproject.org/group/webp-discuss

autogen.sh

@@ -0,0 +1,2 @@
+#! /bin/sh -e
+exec autoreconf -fi

build.gradle

@@ -0,0 +1,444 @@
+// Define dependencies.
+buildscript {
+  repositories {
+    maven {
+      url "https://jcenter.bintray.com"
+    }
+  }
+  dependencies {
+    classpath "com.android.tools.build:gradle:${ANDROID_GRADLE_PLUGIN_VERSION}"
+  }
+}
+
+// Define versions in the project.
+project.ext {
+  buildToolsVersion = "${BUILD_TOOLS_VERSION}"
+  compileSdkVersion = COMPILE_SDK_VERSION.toInteger()
+}
+
+// Core libraries and executables.
+apply plugin: "c"
+def NEON
+model {
+  buildTypes {
+    debug
+    release
+  }
+  platforms {
+    arm {
+      architecture "arm"
+    }
+    arm64 {
+      architecture "arm64"
+    }
+    x86 {
+      architecture "x86"
+    }
+    x64 {
+      architecture "x86_64"
+    }
+    mips32r2
+    mips32r5
+    mips64r6
+  }
+  toolChains {
+    gcc(Gcc) {
+      target("mips32r2") {
+        cCompiler.args "-mips32r2"
+      }
+      target("mips32r5") {
+        cCompiler.args "-mips32r5"
+      }
+      target("mips64r6") {
+        cCompiler.args "-mips64r6"
+      }
+    }
+  }
+  binaries {
+    all {
+      if (toolChain in Gcc) {
+        cCompiler.args "-fPIC"
+        cCompiler.args "-Wall"
+        cCompiler.define "ANDROID"
+        cCompiler.define "HAVE_MALLOC_H"
+      }
+      // Optimizations.
+      if (buildType == buildTypes.release) {
+        if (toolChain in Gcc) {
+          cCompiler.args "-finline-functions"
+          cCompiler.args "-ffast-math"
+          cCompiler.args "-ffunction-sections"
+          cCompiler.args "-fdata-sections"
+        }
+        if (toolChain in Clang) {
+          cCompiler.args "-frename-registers -s"
+        }
+      }
+      // mips32 fails to build with clang from r14b
+      // https://bugs.chromium.org/p/webp/issues/detail?id=343
+      if (toolChain in Clang) {
+        if (getTargetPlatform() == "mips") {
+          cCompiler.args "-no-integrated-as"
+        }
+      }
+      // Check for NEON usage.
+      if (getTargetPlatform() == "arm") {
+        NEON = "c.neon"
+        cCompiler.define "HAVE_CPU_FEATURES_H"
+      } else {
+        NEON = "c"
+      }
+
+      cCompiler.args "-I" + file(".").absolutePath
+    }
+    // Link to pthread for shared libraries.
+    withType(SharedLibraryBinarySpec) {
+      if (toolChain in Gcc) {
+        cCompiler.define "HAVE_PTHREAD"
+        cCompiler.define "WEBP_USE_THREAD"
+        linker.args "-pthread"
+      }
+    }
+  }
+  components {
+    webp(NativeLibrarySpec) {
+      sources {
+        c {
+          source {
+            srcDir "sharpyuv"
+            include "sharpyuv.c"
+            include "sharpyuv_cpu.c"
+            include "sharpyuv_csp.c"
+            include "sharpyuv_dsp.c"
+            include "sharpyuv_gamma.c"
+            include "sharpyuv_neon.c"
+            include "sharpyuv_sse2.c"
+            srcDir "src/dec"
+            include "alpha_dec.c"
+            include "buffer_dec.c"
+            include "frame_dec.c"
+            include "idec_dec.c"
+            include "io_dec.c"
+            include "quant_dec.c"
+            include "tree_dec.c"
+            include "vp8_dec.c"
+            include "vp8l_dec.c"
+            include "webp_dec.c"
+            srcDir "src/dsp"
+            include "alpha_processing.c"
+            include "alpha_processing_mips_dsp_r2.c"
+            include "alpha_processing_neon.$NEON"
+            include "alpha_processing_sse2.c"
+            include "alpha_processing_sse41.c"
+            include "cpu.c"
+            include "dec.c"
+            include "dec_clip_tables.c"
+            include "dec_mips32.c"
+            include "dec_mips_dsp_r2.c"
+            include "dec_msa.c"
+            include "dec_neon.$NEON"
+            include "dec_sse2.c"
+            include "dec_sse41.c"
+            include "filters.c"
+            include "filters_mips_dsp_r2.c"
+            include "filters_msa.c"
+            include "filters_neon.$NEON"
+            include "filters_sse2.c"
+            include "lossless.c"
+            include "lossless_mips_dsp_r2.c"
+            include "lossless_msa.c"
+            include "lossless_neon.$NEON"
+            include "lossless_sse2.c"
+            include "lossless_sse41.c"
+            include "rescaler.c"
+            include "rescaler_mips32.c"
+            include "rescaler_mips_dsp_r2.c"
+            include "rescaler_msa.c"
+            include "rescaler_neon.$NEON"
+            include "rescaler_sse2.c"
+            include "upsampling.c"
+            include "upsampling_mips_dsp_r2.c"
+            include "upsampling_msa.c"
+            include "upsampling_neon.$NEON"
+            include "upsampling_sse2.c"
+            include "upsampling_sse41.c"
+            include "yuv.c"
+            include "yuv_mips32.c"
+            include "yuv_mips_dsp_r2.c"
+            include "yuv_neon.$NEON"
+            include "yuv_sse2.c"
+            include "yuv_sse41.c"
+            srcDir "src/utils"
+            include "bit_reader_utils.c"
+            include "color_cache_utils.c"
+            include "filters_utils.c"
+            include "huffman_utils.c"
+            include "palette.c"
+            include "quant_levels_dec_utils.c"
+            include "random_utils.c"
+            include "rescaler_utils.c"
+            include "thread_utils.c"
+            include "utils.c"
+            srcDir "src/dsp"
+            include "cost.c"
+            include "cost_mips32.c"
+            include "cost_mips_dsp_r2.c"
+            include "cost_neon.$NEON"
+            include "cost_sse2.c"
+            include "enc.c"
+            include "enc_mips32.c"
+            include "enc_mips_dsp_r2.c"
+            include "enc_msa.c"
+            include "enc_neon.$NEON"
+            include "enc_sse2.c"
+            include "enc_sse41.c"
+            include "lossless_enc.c"
+            include "lossless_enc_mips32.c"
+            include "lossless_enc_mips_dsp_r2.c"
+            include "lossless_enc_msa.c"
+            include "lossless_enc_neon.$NEON"
+            include "lossless_enc_sse2.c"
+            include "lossless_enc_sse41.c"
+            include "ssim.c"
+            include "ssim_sse2.c"
+            srcDir "src/enc"
+            include "alpha_enc.c"
+            include "analysis_enc.c"
+            include "backward_references_cost_enc.c"
+            include "backward_references_enc.c"
+            include "config_enc.c"
+            include "cost_enc.c"
+            include "filter_enc.c"
+            include "frame_enc.c"
+            include "histogram_enc.c"
+            include "iterator_enc.c"
+            include "near_lossless_enc.c"
+            include "picture_enc.c"
+            include "picture_csp_enc.c"
+            include "picture_psnr_enc.c"
+            include "picture_rescale_enc.c"
+            include "picture_tools_enc.c"
+            include "predictor_enc.c"
+            include "quant_enc.c"
+            include "syntax_enc.c"
+            include "token_enc.c"
+            include "tree_enc.c"
+            include "vp8l_enc.c"
+            include "webp_enc.c"
+            srcDir "src/utils"
+            include "bit_writer_utils.c"
+            include "huffman_encode_utils.c"
+            include "quant_levels_utils.c"
+          }
+          exportedHeaders {
+            srcDir "src"
+          }
+        }
+      }
+    }
+
+    webpdemux(NativeLibrarySpec) {
+      sources {
+        c {
+          source {
+            srcDir "src/demux"
+            include "anim_decode.c"
+            include "demux.c"
+          }
+        }
+      }
+    }
+
+    webpmux(NativeLibrarySpec) {
+      sources {
+        c {
+          source {
+            srcDir "src/mux/"
+            include "anim_encode.c"
+            include "muxedit.c"
+            include "muxinternal.c"
+            include "muxread.c"
+          }
+        }
+      }
+    }
+
+    // Executables from examples.
+    example_util(NativeLibrarySpec) {
+      binaries {
+        all {
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "example_util.c"
+          }
+        }
+      }
+    }
+
+    imageio_util(NativeLibrarySpec) {
+      binaries {
+        all {
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./imageio"
+            include "imageio_util.c"
+          }
+        }
+      }
+    }
+
+    imagedec(NativeLibrarySpec) {
+      binaries {
+        all {
+          lib library: "webpdemux", linkage: "static"
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./imageio"
+            include "image_dec.c"
+            include "jpegdec.c"
+            include "metadata.c"
+            include "pngdec.c"
+            include "pnmdec.c"
+            include "tiffdec.c"
+            include "webpdec.c"
+          }
+        }
+      }
+    }
+
+    imageenc(NativeLibrarySpec) {
+      binaries {
+        all {
+          lib library: "webp", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./imageio"
+            include "image_enc.c"
+          }
+        }
+      }
+    }
+
+    cwebp(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "imagedec", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+          lib library: "webpdemux", linkage: "static"
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "cwebp.c"
+          }
+        }
+      }
+    }
+
+    dwebp(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "imagedec", linkage: "static"
+          lib library: "imageenc", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+          lib library: "webpdemux", linkage: "static"
+          lib library: "webp"
+        }
+      }
+      sources {
+        c {
+          source {
+              srcDir "./examples"
+              include "dwebp.c"
+          }
+        }
+      }
+    }
+
+    webpmux_example(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+          lib library: "webpmux", linkage: "static"
+          lib library: "webp"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "webpmux.c"
+          }
+        }
+      }
+    }
+
+    img2webp_example(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "imagedec", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+          lib library: "webpmux", linkage: "static"
+          lib library: "webpdemux", linkage: "static"
+          lib library: "webp"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "img2webp.c"
+          }
+        }
+      }
+    }
+
+    webpinfo_example(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+          lib library: "webp"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "webpinfo.c"
+          }
+        }
+      }
+    }
+  }
+  tasks {
+    // Task to test all possible configurations.
+    buildAllExecutables(Task) {
+      dependsOn $.binaries.findAll { it.buildable }
+    }
+  }
+}

cmake/WebPConfig.cmake.in

@@ -0,0 +1,18 @@
+set(WebP_VERSION @PROJECT_VERSION@)
+set(WEBP_VERSION ${WebP_VERSION})
+
+@PACKAGE_INIT@
+
+if(@WEBP_USE_THREAD@)
+  include(CMakeFindDependencyMacro)
+  find_dependency(Threads REQUIRED)
+endif()
+
+include("${CMAKE_CURRENT_LIST_DIR}/@PROJECT_NAME@Targets.cmake")
+
+set_and_check(WebP_INCLUDE_DIR "@PACKAGE_CMAKE_INSTALL_INCLUDEDIR@")
+set(WEBP_INCLUDE_DIRS ${WebP_INCLUDE_DIRS})
+set(WebP_LIBRARIES "@INSTALLED_LIBRARIES@")
+set(WEBP_LIBRARIES "${WebP_LIBRARIES}")
+
+check_required_components(WebP)

cmake/config.h.in

@@ -0,0 +1,116 @@
+/* Adapted from the autotools src/webp/config.h.in.  */
+
+/* Define if building universal (internal helper macro) */
+/* TODO: handle properly in CMake */
+#cmakedefine AC_APPLE_UNIVERSAL_BUILD 1
+
+/* Set to 1 if __builtin_bswap16 is available */
+#cmakedefine HAVE_BUILTIN_BSWAP16 1
+
+/* Set to 1 if __builtin_bswap32 is available */
+#cmakedefine HAVE_BUILTIN_BSWAP32 1
+
+/* Set to 1 if __builtin_bswap64 is available */
+#cmakedefine HAVE_BUILTIN_BSWAP64 1
+
+/* Define to 1 if you have the <cpu-features.h> header file. */
+#cmakedefine HAVE_CPU_FEATURES_H 1
+
+/* Define to 1 if you have the <GLUT/glut.h> header file. */
+#cmakedefine HAVE_GLUT_GLUT_H 1
+
+/* Define to 1 if you have the <GL/glut.h> header file. */
+#cmakedefine HAVE_GL_GLUT_H 1
+
+/* Define to 1 if you have the <OpenGL/glut.h> header file. */
+#cmakedefine HAVE_OPENGL_GLUT_H 1
+
+/* Define to 1 if you have the <shlwapi.h> header file. */
+#cmakedefine HAVE_SHLWAPI_H 1
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#cmakedefine HAVE_UNISTD_H 1
+
+/* Define to 1 if you have the <wincodec.h> header file. */
+#cmakedefine HAVE_WINCODEC_H 1
+
+/* Define to 1 if you have the <windows.h> header file. */
+#cmakedefine HAVE_WINDOWS_H 1
+
+/* Define to the sub-directory in which libtool stores uninstalled libraries.
+   */
+/* TODO: handle properly in CMake */
+#cmakedefine LT_OBJDIR "@LT_OBJDIR@"
+
+/* Name of package */
+#cmakedefine PACKAGE "@PROJECT_NAME@"
+
+/* Define to the address where bug reports for this package should be sent. */
+#cmakedefine PACKAGE_BUGREPORT "@PACKAGE_BUGREPORT@"
+
+/* Define to the full name of this package. */
+#cmakedefine PACKAGE_NAME "@PACKAGE_NAME@"
+
+/* Define to the full name and version of this package. */
+#cmakedefine PACKAGE_STRING "@PACKAGE_STRING@"
+
+/* Define to the one symbol short name of this package. */
+#cmakedefine PACKAGE_TARNAME "@PACKAGE_TARNAME@"
+
+/* Define to the home page for this package. */
+#cmakedefine PACKAGE_URL "@PACKAGE_URL@"
+
+/* Define to the version of this package. */
+#cmakedefine PACKAGE_VERSION "@PACKAGE_VERSION@"
+
+/* Version number of package */
+#cmakedefine VERSION "@VERSION@"
+
+/* Set to 1 if GIF library is installed */
+#cmakedefine WEBP_HAVE_GIF 1
+
+/* Set to 1 if OpenGL is supported */
+#cmakedefine WEBP_HAVE_GL 1
+
+/* Set to 1 if JPEG library is installed */
+#cmakedefine WEBP_HAVE_JPEG 1
+
+/* Set to 1 if NEON is supported */
+#cmakedefine WEBP_HAVE_NEON
+
+/* Set to 1 if runtime detection of NEON is enabled */
+/* TODO: handle properly in CMake */
+#cmakedefine WEBP_HAVE_NEON_RTCD
+
+/* Set to 1 if PNG library is installed */
+#cmakedefine WEBP_HAVE_PNG 1
+
+/* Set to 1 if SDL library is installed */
+#cmakedefine WEBP_HAVE_SDL 1
+
+/* Set to 1 if SSE2 is supported */
+#cmakedefine WEBP_HAVE_SSE2 1
+
+/* Set to 1 if SSE4.1 is supported */
+#cmakedefine WEBP_HAVE_SSE41 1
+
+/* Set to 1 if TIFF library is installed */
+#cmakedefine WEBP_HAVE_TIFF 1
+
+/* Enable near lossless encoding */
+#cmakedefine WEBP_NEAR_LOSSLESS 1
+
+/* Undefine this to disable thread support. */
+#cmakedefine WEBP_USE_THREAD 1
+
+/* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
+   significant byte first (like Motorola and SPARC, unlike Intel). */
+#if defined AC_APPLE_UNIVERSAL_BUILD
+# if defined __BIG_ENDIAN__
+#  define WORDS_BIGENDIAN 1
+# endif
+#else
+# ifndef WORDS_BIGENDIAN
+#  undef WORDS_BIGENDIAN
+# endif
+#endif

cmake/cpu.cmake

@@ -0,0 +1,159 @@
+#  Copyright (c) 2021 Google LLC.
+#
+#  Use of this source code is governed by a BSD-style license
+#  that can be found in the LICENSE file in the root of the source
+#  tree. An additional intellectual property rights grant can be found
+#  in the file PATENTS.  All contributing project authors may
+#  be found in the AUTHORS file in the root of the source tree.
+
+# Check for SIMD extensions.
+include(CMakePushCheckState)
+
+function(webp_check_compiler_flag WEBP_SIMD_FLAG ENABLE_SIMD)
+  if(NOT ENABLE_SIMD)
+    message(STATUS "Disabling ${WEBP_SIMD_FLAG} optimization.")
+    set(WEBP_HAVE_${WEBP_SIMD_FLAG} 0 PARENT_SCOPE)
+    return()
+  endif()
+  unset(WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG} CACHE)
+  cmake_push_check_state()
+  set(CMAKE_REQUIRED_INCLUDES ${CMAKE_CURRENT_SOURCE_DIR})
+  check_c_source_compiles(
+    "
+      #include \"${CMAKE_CURRENT_LIST_DIR}/../src/dsp/dsp.h\"
+      int main(void) {
+        #if !defined(WEBP_USE_${WEBP_SIMD_FLAG})
+        this is not valid code
+        #endif
+        return 0;
+      }
+    "
+    WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG})
+  cmake_pop_check_state()
+  if(WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG})
+    set(WEBP_HAVE_${WEBP_SIMD_FLAG} 1 PARENT_SCOPE)
+  else()
+    set(WEBP_HAVE_${WEBP_SIMD_FLAG} 0 PARENT_SCOPE)
+  endif()
+endfunction()
+
+# those are included in the names of WEBP_USE_* in c++ code.
+set(WEBP_SIMD_FLAGS "SSE41;SSE2;MIPS32;MIPS_DSP_R2;NEON;MSA")
+set(WEBP_SIMD_FILE_EXTENSIONS
+    "_sse41.c;_sse2.c;_mips32.c;_mips_dsp_r2.c;_neon.c;_msa.c")
+if(MSVC AND CMAKE_C_COMPILER_ID STREQUAL "MSVC")
+  # With at least Visual Studio 12 (2013)+ /arch is not necessary to build SSE2
+  # or SSE4 code unless a lesser /arch is forced. MSVC does not have a SSE4
+  # flag, but an AVX one. Using that with SSE4 code risks generating illegal
+  # instructions when used on machines with SSE4 only. The flags are left for
+  # older (untested) versions to avoid any potential compatibility issues.
+  if(MSVC_VERSION GREATER_EQUAL 1800 AND NOT CMAKE_C_FLAGS MATCHES "/arch:")
+    set(SIMD_ENABLE_FLAGS)
+  else()
+    set(SIMD_ENABLE_FLAGS "/arch:AVX;/arch:SSE2;;;;")
+  endif()
+  set(SIMD_DISABLE_FLAGS)
+else()
+  set(SIMD_ENABLE_FLAGS "-msse4.1;-msse2;-mips32;-mdspr2;-mfpu=neon;-mmsa")
+  set(SIMD_DISABLE_FLAGS "-mno-sse4.1;-mno-sse2;;-mno-dspr2;;-mno-msa")
+endif()
+
+set(WEBP_SIMD_FILES_TO_INCLUDE)
+set(WEBP_SIMD_FLAGS_TO_INCLUDE)
+
+if(${ANDROID})
+  if(${ANDROID_ABI} STREQUAL "armeabi-v7a")
+    # This is because Android studio uses the configuration "-march=armv7-a
+    # -mfloat-abi=softfp -mfpu=vfpv3-d16" that does not trigger neon
+    # optimizations but should (as this configuration does not exist anymore).
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mfpu=neon ")
+  endif()
+endif()
+
+list(LENGTH WEBP_SIMD_FLAGS WEBP_SIMD_FLAGS_LENGTH)
+math(EXPR WEBP_SIMD_FLAGS_RANGE "${WEBP_SIMD_FLAGS_LENGTH} - 1")
+
+foreach(I_SIMD RANGE ${WEBP_SIMD_FLAGS_RANGE})
+  # With Emscripten 2.0.9 -msimd128 -mfpu=neon will enable NEON, but the source
+  # will fail to compile.
+  if(EMSCRIPTEN AND ${I_SIMD} GREATER_EQUAL 2)
+    break()
+  endif()
+
+  list(GET WEBP_SIMD_FLAGS ${I_SIMD} WEBP_SIMD_FLAG)
+
+  # First try with no extra flag added as the compiler might have default flags
+  # (especially on Android).
+  unset(WEBP_HAVE_${WEBP_SIMD_FLAG} CACHE)
+  cmake_push_check_state()
+  set(CMAKE_REQUIRED_FLAGS)
+  webp_check_compiler_flag(${WEBP_SIMD_FLAG} ${WEBP_ENABLE_SIMD})
+  if(NOT WEBP_HAVE_${WEBP_SIMD_FLAG})
+    list(GET SIMD_ENABLE_FLAGS ${I_SIMD} SIMD_COMPILE_FLAG)
+    if(EMSCRIPTEN)
+      set(SIMD_COMPILE_FLAG "-msimd128 ${SIMD_COMPILE_FLAG}")
+    endif()
+    set(CMAKE_REQUIRED_FLAGS ${SIMD_COMPILE_FLAG})
+    webp_check_compiler_flag(${WEBP_SIMD_FLAG} ${WEBP_ENABLE_SIMD})
+  else()
+    if(MSVC AND SIMD_ENABLE_FLAGS)
+      # The detection for SSE2/SSE4 support under MSVC is based on the compiler
+      # version so e.g., clang-cl will require flags to enable the assembly.
+      list(GET SIMD_ENABLE_FLAGS ${I_SIMD} SIMD_COMPILE_FLAG)
+    else()
+      set(SIMD_COMPILE_FLAG " ")
+    endif()
+  endif()
+  # Check which files we should include or not.
+  list(GET WEBP_SIMD_FILE_EXTENSIONS ${I_SIMD} WEBP_SIMD_FILE_EXTENSION)
+  file(GLOB SIMD_FILES "${CMAKE_CURRENT_LIST_DIR}/../"
+       "src/dsp/*${WEBP_SIMD_FILE_EXTENSION}")
+  if(WEBP_HAVE_${WEBP_SIMD_FLAG})
+    # Memorize the file and flags.
+    foreach(FILE ${SIMD_FILES})
+      list(APPEND WEBP_SIMD_FILES_TO_INCLUDE ${FILE})
+      list(APPEND WEBP_SIMD_FLAGS_TO_INCLUDE ${SIMD_COMPILE_FLAG})
+    endforeach()
+  else()
+    # Remove the file from the list.
+    foreach(FILE ${SIMD_FILES})
+      list(APPEND WEBP_SIMD_FILES_NOT_TO_INCLUDE ${FILE})
+    endforeach()
+    # Explicitly disable SIMD.
+    if(SIMD_DISABLE_FLAGS)
+      list(GET SIMD_DISABLE_FLAGS ${I_SIMD} SIMD_COMPILE_FLAG)
+      include(CheckCCompilerFlag)
+      if(SIMD_COMPILE_FLAG)
+        # Between 3.17.0 and 3.18.2 check_cxx_compiler_flag() sets a normal
+        # variable at parent scope while check_cxx_source_compiles() continues
+        # to set an internal cache variable, so we unset both to avoid the
+        # failure / success state persisting between checks. See
+        # https://gitlab.kitware.com/cmake/cmake/-/issues/21207.
+        unset(HAS_COMPILE_FLAG)
+        unset(HAS_COMPILE_FLAG CACHE)
+        check_c_compiler_flag(${SIMD_COMPILE_FLAG} HAS_COMPILE_FLAG)
+        if(HAS_COMPILE_FLAG)
+          # Do one more check for Clang to circumvent CMake issue 13194.
+          if(COMMAND check_compiler_flag_common_patterns)
+            # Only in CMake 3.0 and above.
+            check_compiler_flag_common_patterns(COMMON_PATTERNS)
+          else()
+            set(COMMON_PATTERNS)
+          endif()
+          set(CMAKE_REQUIRED_DEFINITIONS ${SIMD_COMPILE_FLAG})
+          check_c_source_compiles(
+            "int main(void) {return 0;}" FLAG_${SIMD_COMPILE_FLAG} FAIL_REGEX
+            "warning: argument unused during compilation:" ${COMMON_PATTERNS})
+          if(NOT FLAG_${SIMD_COMPILE_FLAG})
+            unset(HAS_COMPILE_FLAG)
+            unset(HAS_COMPILE_FLAG CACHE)
+          endif()
+        endif()
+        if(HAS_COMPILE_FLAG)
+          set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${SIMD_COMPILE_FLAG}")
+        endif()
+      endif()
+    endif()
+  endif()
+  cmake_pop_check_state()
+endforeach()

cmake/deps.cmake

@@ -0,0 +1,172 @@
+#  Copyright (c) 2021 Google LLC.
+#
+#  Use of this source code is governed by a BSD-style license
+#  that can be found in the LICENSE file in the root of the source
+#  tree. An additional intellectual property rights grant can be found
+#  in the file PATENTS.  All contributing project authors may
+#  be found in the AUTHORS file in the root of the source tree.
+
+# Generate the config.h to compile with specific intrinsics / libs.
+
+# Check for compiler options.
+include(CheckCSourceCompiles)
+check_c_source_compiles(
+  "
+    int main(void) {
+      (void)__builtin_bswap16(0);
+      return 0;
+    }
+  "
+  HAVE_BUILTIN_BSWAP16)
+check_c_source_compiles(
+  "
+    int main(void) {
+      (void)__builtin_bswap32(0);
+      return 0;
+    }
+  "
+  HAVE_BUILTIN_BSWAP32)
+check_c_source_compiles(
+  "
+    int main(void) {
+      (void)__builtin_bswap64(0);
+      return 0;
+    }
+  "
+  HAVE_BUILTIN_BSWAP64)
+
+# Check for libraries.
+if(WEBP_USE_THREAD)
+  find_package(Threads)
+  if(Threads_FOUND)
+    # work around cmake bug on QNX (https://cmake.org/Bug/view.php?id=11333)
+    if(CMAKE_USE_PTHREADS_INIT AND NOT CMAKE_SYSTEM_NAME STREQUAL "QNX")
+      set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pthread")
+    endif()
+    list(APPEND WEBP_DEP_LIBRARIES Threads::Threads)
+  endif()
+  set(WEBP_USE_THREAD ${Threads_FOUND})
+endif()
+
+# TODO: this seems unused, check with autotools.
+set(LT_OBJDIR ".libs/")
+
+# Only useful for vwebp, so useless for now.
+find_package(OpenGL)
+set(WEBP_HAVE_GL ${OPENGL_FOUND})
+
+# Check if we need to link to the C math library. We do not look for it as it is
+# not found when cross-compiling, while it is here.
+check_c_source_compiles(
+  "
+    #include <math.h>
+    int main(int argc, char** argv) {
+      return (int)pow(argc, 2.5);
+    }
+  "
+  HAVE_MATH_LIBRARY)
+if(NOT HAVE_MATH_LIBRARY)
+  message(STATUS "Adding -lm flag.")
+  list(APPEND SHARPYUV_DEP_LIBRARIES m)
+  list(APPEND WEBP_DEP_LIBRARIES m)
+endif()
+
+# Find the standard image libraries.
+set(WEBP_DEP_IMG_LIBRARIES)
+set(WEBP_DEP_IMG_INCLUDE_DIRS)
+if(WEBP_FIND_IMG_LIBS)
+  foreach(I_LIB PNG JPEG TIFF)
+    # Disable tiff when compiling in static mode as it is failing on Ubuntu.
+    if(WEBP_LINK_STATIC AND ${I_LIB} STREQUAL "TIFF")
+      message(STATUS "TIFF is disabled when statically linking.")
+      continue()
+    endif()
+    find_package(${I_LIB})
+    set(WEBP_HAVE_${I_LIB} ${${I_LIB}_FOUND})
+    if(${I_LIB}_FOUND)
+      list(APPEND WEBP_DEP_IMG_LIBRARIES ${${I_LIB}_LIBRARIES})
+      list(APPEND WEBP_DEP_IMG_INCLUDE_DIRS ${${I_LIB}_INCLUDE_DIR}
+           ${${I_LIB}_INCLUDE_DIRS})
+    endif()
+  endforeach()
+  if(WEBP_DEP_IMG_INCLUDE_DIRS)
+    list(REMOVE_DUPLICATES WEBP_DEP_IMG_INCLUDE_DIRS)
+  endif()
+
+  # GIF detection, gifdec isn't part of the imageio lib.
+  include(CMakePushCheckState)
+  set(WEBP_DEP_GIF_LIBRARIES)
+  set(WEBP_DEP_GIF_INCLUDE_DIRS)
+  find_package(GIF)
+  set(WEBP_HAVE_GIF ${GIF_FOUND})
+  if(GIF_FOUND)
+    # GIF find_package only locates the header and library, it doesn't fail
+    # compile tests when detecting the version, but falls back to 3 (as of at
+    # least cmake 3.7.2). Make sure the library links to avoid incorrect
+    # detection when cross compiling.
+    cmake_push_check_state()
+    set(CMAKE_REQUIRED_LIBRARIES ${GIF_LIBRARIES})
+    set(CMAKE_REQUIRED_INCLUDES ${GIF_INCLUDE_DIR})
+    check_c_source_compiles(
+      "
+      #include <gif_lib.h>
+      int main(void) {
+        (void)DGifOpenFileHandle;
+        return 0;
+      }
+      "
+      GIF_COMPILES)
+    cmake_pop_check_state()
+    if(GIF_COMPILES)
+      list(APPEND WEBP_DEP_GIF_LIBRARIES ${GIF_LIBRARIES})
+      list(APPEND WEBP_DEP_GIF_INCLUDE_DIRS ${GIF_INCLUDE_DIR})
+    else()
+      unset(GIF_FOUND)
+    endif()
+  endif()
+endif()
+
+# Check for specific headers.
+include(CheckIncludeFiles)
+check_include_files(GLUT/glut.h HAVE_GLUT_GLUT_H)
+check_include_files(GL/glut.h HAVE_GL_GLUT_H)
+check_include_files(OpenGL/glut.h HAVE_OPENGL_GLUT_H)
+check_include_files(shlwapi.h HAVE_SHLWAPI_H)
+check_include_files(unistd.h HAVE_UNISTD_H)
+check_include_files(wincodec.h HAVE_WINCODEC_H)
+check_include_files(windows.h HAVE_WINDOWS_H)
+
+# Windows specifics
+if(HAVE_WINCODEC_H)
+  list(APPEND WEBP_DEP_LIBRARIES shlwapi ole32 windowscodecs)
+endif()
+
+# Check for SIMD extensions.
+include(${CMAKE_CURRENT_LIST_DIR}/cpu.cmake)
+
+# Define extra info.
+set(PACKAGE ${PROJECT_NAME})
+set(PACKAGE_NAME ${PROJECT_NAME})
+
+# Read from configure.ac.
+file(READ ${CMAKE_CURRENT_SOURCE_DIR}/configure.ac CONFIGURE_AC)
+string(REGEX MATCHALL "\\[([0-9a-z\\.:/]*)\\]" CONFIGURE_AC_PACKAGE_INFO
+             ${CONFIGURE_AC})
+function(strip_bracket VAR)
+  string(LENGTH ${${VAR}} TMP_LEN)
+  math(EXPR TMP_LEN ${TMP_LEN}-2)
+  string(SUBSTRING ${${VAR}} 1 ${TMP_LEN} TMP_SUB)
+  set(${VAR} ${TMP_SUB} PARENT_SCOPE)
+endfunction()
+
+list(GET CONFIGURE_AC_PACKAGE_INFO 1 PACKAGE_VERSION)
+strip_bracket(PACKAGE_VERSION)
+list(GET CONFIGURE_AC_PACKAGE_INFO 2 PACKAGE_BUGREPORT)
+strip_bracket(PACKAGE_BUGREPORT)
+list(GET CONFIGURE_AC_PACKAGE_INFO 3 PACKAGE_URL)
+strip_bracket(PACKAGE_URL)
+
+# Build more info.
+set(PACKAGE_STRING "${PACKAGE_NAME} ${PACKAGE_VERSION}")
+set(PACKAGE_TARNAME ${PACKAGE_NAME})
+set(VERSION ${PACKAGE_VERSION})

codereview.settings

@@ -0,0 +1,4 @@
+# This file is used by git cl to get repository specific information.
+GERRIT_HOST: True
+CODE_REVIEW_SERVER: chromium-review.googlesource.com
+GERRIT_SQUASH_UPLOADS: False

configure.ac

@@ -0,0 +1,803 @@
+AC_INIT([libwebp], [1.3.1],
+        [https://bugs.chromium.org/p/webp],,
+        [https://developers.google.com/speed/webp])
+AC_CANONICAL_HOST
+AC_PREREQ([2.60])
+AM_INIT_AUTOMAKE([-Wall foreign subdir-objects])
+
+dnl === automake >= 1.12 requires this for 'unusual archivers' support.
+dnl === it must occur before LT_INIT (AC_PROG_LIBTOOL).
+m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
+
+dnl === AC_PROG_LIBTOOL is deprecated.
+m4_ifdef([LT_INIT], [LT_INIT], [AC_PROG_LIBTOOL])
+AC_PROG_SED
+AM_PROG_CC_C_O
+
+dnl === Enable less verbose output when building.
+m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
+
+dnl == test endianness
+AC_C_BIGENDIAN
+
+dnl === SET_IF_UNSET(shell_var, value)
+dnl ===   Set the shell variable 'shell_var' to 'value' if it is unset.
+AC_DEFUN([SET_IF_UNSET], [test "${$1+set}" = "set" || $1=$2])
+
+AC_ARG_ENABLE([everything],
+              AS_HELP_STRING([--enable-everything],
+                             [Enable all optional targets. These can still be
+                              disabled with --disable-target]),
+              [SET_IF_UNSET([enable_libsharpyuv], [$enableval])
+               SET_IF_UNSET([enable_libwebpdecoder], [$enableval])
+               SET_IF_UNSET([enable_libwebpdemux], [$enableval])
+               SET_IF_UNSET([enable_libwebpextras], [$enableval])
+               SET_IF_UNSET([enable_libwebpmux], [$enableval])])
+
+dnl === Check whether libwebpmux should be built
+AC_MSG_CHECKING(whether libwebpmux is to be built)
+AC_ARG_ENABLE([libwebpmux],
+              AS_HELP_STRING([--disable-libwebpmux],
+                             [Disable libwebpmux @<:@default=no@:>@]),
+              [], [enable_libwebpmux=yes])
+AC_MSG_RESULT(${enable_libwebpmux-no})
+AM_CONDITIONAL([BUILD_MUX], [test "$enable_libwebpmux" = "yes"])
+
+dnl === Check whether libwebpdemux should be built
+AC_MSG_CHECKING(whether libwebpdemux is to be built)
+AC_ARG_ENABLE([libwebpdemux],
+              AS_HELP_STRING([--disable-libwebpdemux],
+                             [Disable libwebpdemux @<:@default=no@:>@]),
+              [], [enable_libwebpdemux=yes])
+AC_MSG_RESULT(${enable_libwebpdemux-no})
+AM_CONDITIONAL([BUILD_DEMUX], [test "$enable_libwebpdemux" = "yes"])
+
+dnl === Check whether decoder library should be built.
+AC_MSG_CHECKING(whether decoder library is to be built)
+AC_ARG_ENABLE([libwebpdecoder],
+              AS_HELP_STRING([--enable-libwebpdecoder],
+                             [Build libwebpdecoder @<:@default=no@:>@]))
+AC_MSG_RESULT(${enable_libwebpdecoder-no})
+AM_CONDITIONAL([BUILD_LIBWEBPDECODER], [test "$enable_libwebpdecoder" = "yes"])
+
+dnl === Check whether libwebpextras should be built
+AC_MSG_CHECKING(whether libwebpextras is to be built)
+AC_ARG_ENABLE([libwebpextras],
+              AS_HELP_STRING([--enable-libwebpextras],
+                             [Build libwebpextras @<:@default=no@:>@]))
+AC_MSG_RESULT(${enable_libwebpextras-no})
+AM_CONDITIONAL([BUILD_EXTRAS], [test "$enable_libwebpextras" = "yes"])
+
+dnl === If --enable-asserts is not defined, define NDEBUG
+
+AC_MSG_CHECKING(whether asserts are enabled)
+AC_ARG_ENABLE([asserts],
+              AS_HELP_STRING([--enable-asserts],
+                             [Enable assert checks]))
+if test "x${enable_asserts-no}" = "xno"; then
+  AM_CPPFLAGS="${AM_CPPFLAGS} -DNDEBUG"
+fi
+AC_MSG_RESULT(${enable_asserts-no})
+AC_SUBST([AM_CPPFLAGS])
+
+AC_ARG_WITH([pkgconfigdir], AS_HELP_STRING([--with-pkgconfigdir=DIR],
+            [Path to the pkgconfig directory @<:@LIBDIR/pkgconfig@:>@]),
+            [pkgconfigdir="$withval"], [pkgconfigdir='${libdir}/pkgconfig'])
+AC_SUBST([pkgconfigdir])
+
+dnl === TEST_AND_ADD_CFLAGS(var, flag)
+dnl ===   Checks whether $CC supports 'flag' and adds it to 'var'
+dnl ===   on success.
+AC_DEFUN([TEST_AND_ADD_CFLAGS],
+         [SAVED_CFLAGS="$CFLAGS"
+          CFLAGS="-Werror $2"
+          AC_MSG_CHECKING([whether $CC supports $2])
+          dnl Note AC_LANG_PROGRAM([]) uses an old-style main definition.
+          AC_COMPILE_IFELSE([AC_LANG_SOURCE([int main(void) { return 0; }])],
+                            [AC_MSG_RESULT([yes])]
+                            dnl Simply append the variable avoiding a
+                            dnl compatibility ifdef for AS_VAR_APPEND as this
+                            dnl variable shouldn't grow all that large.
+                            [$1="${$1} $2"],
+                            [AC_MSG_RESULT([no])])
+          CFLAGS="$SAVED_CFLAGS"])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-fvisibility=hidden])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wall])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wconstant-conversion])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wdeclaration-after-statement])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wextra])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wfloat-conversion])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wformat -Wformat-nonliteral])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wformat -Wformat-security])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wmissing-declarations])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wmissing-prototypes])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wold-style-definition])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wparentheses-equality])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wshadow])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wshorten-64-to-32])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wundef])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wunreachable-code-aggressive])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wunreachable-code])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wunused-but-set-variable])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wunused])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wvla])
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62040
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61622
+AS_IF([test "$GCC" = "yes" ], [
+       gcc_version=`$CC -dumpversion`
+       gcc_wht_bug=""
+       case "$host_cpu" in
+         aarch64|arm64)
+          case "$gcc_version" in
+            4.9|4.9.0|4.9.1) gcc_wht_bug=yes ;;
+          esac
+       esac
+       AS_IF([test "$gcc_wht_bug" = "yes"], [
+              TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-frename-registers])])])
+# Use -flax-vector-conversions, if available, when building intrinsics with
+# older versions of gcc. The flag appeared in 4.3.x, but if backported, and
+# -fno-lax-vector-conversions is set, errors may occur with the intrinsics
+# files along with the older system includes, e.g., emmintrin.h.
+# Originally observed with cc (GCC) 4.2.1 20070831 patched [FreeBSD] (9.3).
+# https://bugs.chromium.org/p/webp/issues/detail?id=274
+AS_IF([test "$GCC" = "yes" ], [
+       case "$host_cpu" in
+         amd64|i?86|x86_64)
+           AC_COMPILE_IFELSE(
+             dnl only check for -flax-vector-conversions with older gcc, skip
+             dnl clang as it reports itself as 4.2.1, but the flag isn't needed.
+             [AC_LANG_SOURCE([#if !defined(__clang__) && defined(__GNUC__) && \
+                                  ((__GNUC__ << 8) | __GNUC_MINOR__) < 0x403
+                              #error old gcc
+                              #endif
+                              int main(void) { return 0; }
+                             ])],,
+              [TEST_AND_ADD_CFLAGS([INTRINSICS_CFLAGS],
+                                   [-flax-vector-conversions])])
+           ;;
+       esac])
+AC_SUBST([AM_CFLAGS])
+
+dnl === Check for machine specific flags
+AC_ARG_ENABLE([sse4.1],
+              AS_HELP_STRING([--disable-sse4.1],
+                             [Disable detection of SSE4.1 support
+                              @<:@default=auto@:>@]))
+
+AS_IF([test "x$enable_sse4_1" != "xno" -a "x$enable_sse2" != "xno"], [
+  SSE41_FLAGS="$INTRINSICS_CFLAGS $SSE41_FLAGS"
+  TEST_AND_ADD_CFLAGS([SSE41_FLAGS], [-msse4.1])
+  AS_IF([test -n "$SSE41_FLAGS"], [
+    SAVED_CFLAGS=$CFLAGS
+    CFLAGS="$CFLAGS $SSE41_FLAGS"
+    AC_CHECK_HEADER([smmintrin.h],
+                    [AC_DEFINE(WEBP_HAVE_SSE41, [1],
+                     [Set to 1 if SSE4.1 is supported])],
+                    [SSE41_FLAGS=""])
+    CFLAGS=$SAVED_CFLAGS])
+  AC_SUBST([SSE41_FLAGS])])
+
+AC_ARG_ENABLE([sse2],
+              AS_HELP_STRING([--disable-sse2],
+                             [Disable detection of SSE2 support
+                              @<:@default=auto@:>@]))
+
+AS_IF([test "x$enable_sse2" != "xno"], [
+  SSE2_FLAGS="$INTRINSICS_CFLAGS $SSE2_FLAGS"
+  TEST_AND_ADD_CFLAGS([SSE2_FLAGS], [-msse2])
+  AS_IF([test -n "$SSE2_FLAGS"], [
+    SAVED_CFLAGS=$CFLAGS
+    CFLAGS="$CFLAGS $SSE2_FLAGS"
+    AC_CHECK_HEADER([emmintrin.h],
+                    [AC_DEFINE(WEBP_HAVE_SSE2, [1],
+                     [Set to 1 if SSE2 is supported])],
+                    [SSE2_FLAGS=""])
+    CFLAGS=$SAVED_CFLAGS])
+  AC_SUBST([SSE2_FLAGS])])
+
+AC_ARG_ENABLE([neon],
+              AS_HELP_STRING([--disable-neon],
+                             [Disable detection of NEON support
+                              @<:@default=auto@:>@]))
+
+AC_ARG_ENABLE([neon_rtcd],
+              AS_HELP_STRING([--disable-neon-rtcd],
+                             [Disable runtime detection of NEON support via
+                              /proc/cpuinfo on Linux hosts
+                              @<:@default=auto@:>@]))
+# For ARM(7) hosts:
+# Both NEON flags unset and NEON support detected = build all modules with NEON
+# NEON detected with the use of -mfpu=neon = build only NEON modules with NEON
+AS_IF([test "x$enable_neon" != "xno"], [
+  case "$host_cpu" in
+    arm|armv7*)
+      # Test for NEON support without flags before falling back to -mfpu=neon
+      for flag in '' '-mfpu=neon'; do
+        LOCAL_NEON_FLAGS="$INTRINSICS_CFLAGS $NEON_FLAGS"
+        TEST_AND_ADD_CFLAGS([LOCAL_NEON_FLAGS], [$flag])
+        SAVED_CFLAGS=$CFLAGS
+        CFLAGS="$CFLAGS $LOCAL_NEON_FLAGS"
+
+        dnl Note AC_LANG_PROGRAM([]) uses an old-style main definition.
+        AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+          #include <arm_neon.h>
+          int main(void) {
+            int8x8_t v = vdup_n_s8(0);
+            (void)v;
+            return 0;
+          }])],
+          [NEON_FLAGS="$(echo $LOCAL_NEON_FLAGS | $SED 's/^ *//')"
+           AS_IF([test -n "$NEON_FLAGS"], [
+             AS_IF([test "${host_os%%-*}" = "linux" -o \
+                         "x$enable_neon_rtcd" = "xno"], [
+               CFLAGS=$SAVED_CFLAGS
+               AC_DEFINE(WEBP_HAVE_NEON, [1], [Set to 1 if NEON is supported])
+               break
+             ],[
+               AC_MSG_WARN(m4_normalize([NEON runtime cpu-detection is
+                                         unavailable for ${host_os%%-*}. Force
+                                         with CFLAGS=-mfpu=neon or
+                                         --disable-neon-rtcd.]))
+               enable_neon_rtcd=no
+               NEON_FLAGS=""
+             ])
+           ],[
+             CFLAGS=$SAVED_CFLAGS
+             AC_DEFINE(WEBP_HAVE_NEON, [1], [Set to 1 if NEON is supported])
+             break
+           ])])
+        CFLAGS=$SAVED_CFLAGS
+      done
+
+      AS_IF([test -n "$NEON_FLAGS"], [
+        # If NEON is available and rtcd is disabled apply NEON_FLAGS globally.
+        AS_IF([test "x$enable_neon_rtcd" = "xno"], [
+          AM_CFLAGS="$AM_CFLAGS $NEON_FLAGS"
+          NEON_FLAGS=""],
+          [AC_DEFINE(WEBP_HAVE_NEON_RTCD, [1],
+                     [Set to 1 if runtime detection of NEON is enabled])])])
+
+      case "$host_os" in
+        *android*) AC_CHECK_HEADERS([cpu-features.h]) ;;
+      esac
+      ;;
+    aarch64*|arm64*)
+      AC_DEFINE(WEBP_HAVE_NEON, [1], [Set to 1 if NEON is supported])
+      ;;
+  esac
+  AC_SUBST([NEON_FLAGS])])
+
+dnl === CLEAR_LIBVARS([var_pfx])
+dnl ===   Clears <var_pfx>_{INCLUDES,LIBS}.
+AC_DEFUN([CLEAR_LIBVARS], [$1_INCLUDES=""; $1_LIBS=""])
+
+dnl === WITHLIB_OPTION([opt_pfx], [outvar_pfx])
+dnl ===   Defines --with-<opt_pfx>{include,lib}dir options which set
+dnl ===   the variables <outvar_pfx>_{INCLUDES,LIBS}.
+AC_DEFUN([WITHLIB_OPTION],
+  [AC_ARG_WITH([$1includedir],
+               AS_HELP_STRING([--with-$1includedir=DIR],
+                              [use $2 includes from DIR]),
+               $2_INCLUDES="-I$withval")
+   AC_ARG_WITH([$1libdir],
+               AS_HELP_STRING([--with-$1libdir=DIR],
+                              [use $2 libraries from DIR]),
+               [$2_LIBS="-L$withval"])])
+
+dnl === LIBCHECK_PROLOGUE([var_pfx])
+dnl ===   Caches the current values of CPPFLAGS/LIBS in SAVED_* then
+dnl ===   prepends the current values with <var_pfx>_{INCLUDES,LIBS}.
+AC_DEFUN([LIBCHECK_PROLOGUE],
+         [SAVED_CPPFLAGS=$CPPFLAGS
+          SAVED_LIBS=$LIBS
+          CPPFLAGS="$$1_INCLUDES $CPPFLAGS"
+          LIBS="$$1_LIBS $LIBS"])
+
+dnl === LIBCHECK_EPILOGUE([var_pfx])
+dnl ===   Restores the values of CPPFLAGS/LIBS from SAVED_* and exports
+dnl ===   <var_pfx>_{INCLUDES,LIBS} with AC_SUBST.
+AC_DEFUN([LIBCHECK_EPILOGUE],
+         [AC_SUBST($1_LIBS)
+          AC_SUBST($1_INCLUDES)
+          CPPFLAGS=$SAVED_CPPFLAGS
+          LIBS=$SAVED_LIBS])
+
+dnl === Check for gcc builtins
+
+dnl === CHECK_FOR_BUILTIN([builtin], [param], [define])
+dnl ===   links a C AC_LANG_PROGRAM, with <builtin>(<param>)
+dnl ===   AC_DEFINE'ing <define> if successful.
+AC_DEFUN([CHECK_FOR_BUILTIN],
+         [AC_LANG_PUSH([C])
+          AC_MSG_CHECKING([for $1])
+          AC_LINK_IFELSE([AC_LANG_PROGRAM([], [(void)$1($2)])],
+                         [AC_MSG_RESULT([yes])
+                          AC_DEFINE([$3], [1],
+                                    [Set to 1 if $1 is available])],
+                         [AC_MSG_RESULT([no])]),
+          AC_LANG_POP])
+
+dnl AC_CHECK_FUNC doesn't work with builtin's.
+CHECK_FOR_BUILTIN([__builtin_bswap16], [1u << 15], [HAVE_BUILTIN_BSWAP16])
+CHECK_FOR_BUILTIN([__builtin_bswap32], [1u << 31], [HAVE_BUILTIN_BSWAP32])
+CHECK_FOR_BUILTIN([__builtin_bswap64], [1ull << 63], [HAVE_BUILTIN_BSWAP64])
+
+dnl === Check for pthread support
+AC_ARG_ENABLE([threading],
+              AS_HELP_STRING([--disable-threading],
+                             [Disable detection of thread support]),,
+              [enable_threading=yes])
+if test "$enable_threading" = "yes"; then
+  AC_MSG_NOTICE([checking for threading support...])
+  AX_PTHREAD([AC_DEFINE([WEBP_USE_THREAD], [1],
+                        [Undefine this to disable thread support.])
+              LIBS="$PTHREAD_LIBS $LIBS"
+              CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+              CC="$PTHREAD_CC"
+             ],
+             [AC_CHECK_FUNC([_beginthreadex],
+                            [AC_DEFINE([WEBP_USE_THREAD], [1],
+                                       [Undefine this to disable thread
+                                        support.])],
+                            [enable_threading=no])])
+fi
+AC_MSG_NOTICE([checking if threading is enabled... ${enable_threading-no}])
+
+dnl === check for OpenGL/GLUT support ===
+
+AC_ARG_ENABLE([gl], AS_HELP_STRING([--disable-gl],
+                                   [Disable detection of OpenGL support
+                                    @<:@default=auto@:>@]))
+AS_IF([test "x$enable_gl" != "xno"], [
+  CLEAR_LIBVARS([GL])
+  WITHLIB_OPTION([gl], [GL])
+
+  LIBCHECK_PROLOGUE([GL])
+
+  glut_cflags="none"
+  glut_ldflags="none"
+  case $host_os in
+    darwin*)
+      # Special case for OSX builds. Append these to give the user a chance to
+      # override with --with-gl*
+      glut_cflags="$glut_cflags|-framework GLUT -framework OpenGL"
+      glut_ldflags="$glut_ldflags|-framework GLUT -framework OpenGL"
+      # quiet deprecation warnings for glut
+      TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wno-deprecated-declarations])
+      ;;
+  esac
+
+  GLUT_SAVED_CPPFLAGS="$CPPFLAGS"
+  SAVED_IFS="$IFS"
+  IFS="|"
+  for flag in $glut_cflags; do
+    # restore IFS immediately as the autoconf macros may need the default.
+    IFS="$SAVED_IFS"
+    unset ac_cv_header_GL_glut_h
+    unset ac_cv_header_OpenGL_glut_h
+
+    case $flag in
+      none) ;;
+      *) CPPFLAGS="$flag $CPPFLAGS";;
+    esac
+    AC_CHECK_HEADERS([GL/glut.h GLUT/glut.h OpenGL/glut.h],
+                     [glut_headers=yes;
+                      test "$flag" = "none" || GL_INCLUDES="$CPPFLAGS";
+                      break])
+    CPPFLAGS="$GLUT_SAVED_CPPFLAGS"
+    test "$glut_headers" = "yes" && break
+  done
+  IFS="$SAVED_IFS"
+
+  if test "$glut_headers" = "yes"; then
+    AC_LANG_PUSH([C])
+    GLUT_SAVED_LDFLAGS="$LDFLAGS"
+    SAVED_IFS="$IFS"
+    IFS="|"
+    for flag in $glut_ldflags; do
+      # restore IFS immediately as the autoconf macros may need the default.
+      IFS="$SAVED_IFS"
+      unset ac_cv_search_glBegin
+
+      case $flag in
+        none) ;;
+        *) LDFLAGS="$flag $LDFLAGS";;
+      esac
+
+      # find libGL
+      GL_SAVED_LIBS="$LIBS"
+      AC_SEARCH_LIBS([glBegin], [GL OpenGL opengl32])
+      LIBS="$GL_SAVED_LIBS"
+
+      # A direct link to libGL may not be necessary on e.g., linux.
+      GLUT_SAVED_LIBS="$LIBS"
+      for lib in "" "-lglut" "-lglut $ac_cv_search_glBegin"; do
+        LIBS="$lib"
+        AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM([
+             #ifdef __cplusplus
+             # define EXTERN_C extern "C"
+             #else
+             # define EXTERN_C
+             #endif
+             EXTERN_C char glOrtho();
+             EXTERN_C char glutMainLoop();
+            ],[
+             glOrtho();
+             glutMainLoop();
+            ])
+          ],
+          AC_DEFINE(WEBP_HAVE_GL, [1],
+                    [Set to 1 if OpenGL is supported])
+          [glut_support=yes], []
+        )
+        if test "$glut_support" = "yes"; then
+          GL_LIBS="$LDFLAGS $lib"
+          break
+        fi
+      done
+      LIBS="$GLUT_SAVED_LIBS"
+      LDFLAGS="$GLUT_SAVED_LDFLAGS"
+      test "$glut_support" = "yes" && break
+    done
+    IFS="$SAVED_IFS"
+    AC_LANG_POP
+  fi
+
+  LIBCHECK_EPILOGUE([GL])
+
+  if test "$glut_support" = "yes" -a "$enable_libwebpdemux" = "yes"; then
+    build_vwebp=yes
+  else
+    AC_MSG_NOTICE(
+      m4_normalize([Not building vwebp.
+                    OpenGL libraries and --enable-libwebpdemux are required.]))
+  fi
+])
+AM_CONDITIONAL([BUILD_VWEBP], [test "$build_vwebp" = "yes"])
+
+dnl === check for SDL support ===
+
+AC_ARG_ENABLE([sdl],
+              AS_HELP_STRING([--disable-sdl],
+                             [Disable detection of SDL support
+                              @<:@default=auto@:>@]))
+AS_IF([test "x$enable_sdl" != "xno"], [
+  CLEAR_LIBVARS([SDL])
+  AC_PATH_PROGS([LIBSDL_CONFIG], [sdl-config])
+  if test -n "$LIBSDL_CONFIG"; then
+    SDL_INCLUDES=`$LIBSDL_CONFIG --cflags`
+    SDL_LIBS="`$LIBSDL_CONFIG --libs`"
+  fi
+
+  WITHLIB_OPTION([sdl], [SDL])
+
+  sdl_header="no"
+  LIBCHECK_PROLOGUE([SDL])
+  AC_CHECK_HEADER([SDL/SDL.h], [sdl_header="SDL/SDL.h"],
+                  [AC_CHECK_HEADER([SDL.h], [sdl_header="SDL.h"],
+                  [AC_MSG_WARN(SDL library not available - no sdl.h)])])
+  if test x"$sdl_header" != "xno"; then
+    AC_LANG_PUSH(C)
+    SDL_SAVED_LIBS="$LIBS"
+    for lib in "" "-lSDL" "-lSDLmain -lSDL"; do
+      LIBS="$SDL_SAVED_LIBS $lib"
+      # Perform a full link to ensure SDL_main is resolved if needed.
+      AC_LINK_IFELSE(
+        [AC_LANG_SOURCE([
+           #include <$sdl_header>
+           int main(int argc, char** argv) {
+             SDL_Init(0);
+             return 0;
+           }])],
+        [SDL_LIBS="$LDFLAGS $LIBS"
+         SDL_INCLUDES="$SDL_INCLUDES -DWEBP_HAVE_SDL"
+         AC_DEFINE(WEBP_HAVE_SDL, [1],
+                   [Set to 1 if SDL library is installed])
+         sdl_support=yes]
+      )
+      if test x"$sdl_support" = "xyes"; then
+        break
+      fi
+    done
+    # LIBS is restored by LIBCHECK_EPILOGUE
+    AC_LANG_POP
+    if test x"$sdl_header" = "xSDL.h"; then
+      SDL_INCLUDES="$SDL_INCLUDES -DWEBP_HAVE_JUST_SDL_H"
+    fi
+  fi
+  LIBCHECK_EPILOGUE([SDL])
+
+  if test x"$sdl_support" = "xyes"; then
+    build_vwebp_sdl=yes
+  else
+    AC_MSG_NOTICE([Not building vwebp-sdl. SDL library is required.])
+  fi
+])
+
+AM_CONDITIONAL([BUILD_VWEBP_SDL], [test "$build_vwebp_sdl" = "yes"])
+
+dnl === check for PNG support ===
+
+AC_ARG_ENABLE([png], AS_HELP_STRING([--disable-png],
+                                    [Disable detection of PNG format support
+                                     @<:@default=auto@:>@]))
+AS_IF([test "x$enable_png" != "xno"], [
+  CLEAR_LIBVARS([PNG])
+  AC_PATH_PROGS([LIBPNG_CONFIG],
+                [libpng-config libpng16-config libpng15-config libpng14-config \
+                 libpng12-config])
+  if test -n "$LIBPNG_CONFIG"; then
+    PNG_INCLUDES=`$LIBPNG_CONFIG --cflags`
+    PNG_LIBS="`$LIBPNG_CONFIG --ldflags`"
+  fi
+
+  WITHLIB_OPTION([png], [PNG])
+
+  LIBCHECK_PROLOGUE([PNG])
+  AC_CHECK_HEADER(png.h,
+    AC_SEARCH_LIBS(png_get_libpng_ver, [png],
+                   [test "$ac_cv_search_png_get_libpng_ver" = "none required" \
+                      || PNG_LIBS="$PNG_LIBS $ac_cv_search_png_get_libpng_ver"
+                    PNG_INCLUDES="$PNG_INCLUDES -DWEBP_HAVE_PNG"
+                    AC_DEFINE(WEBP_HAVE_PNG, [1],
+                              [Set to 1 if PNG library is installed])
+                    png_support=yes
+                   ],
+                   [AC_MSG_WARN(Optional png library not found)
+                    PNG_LIBS=""
+                    PNG_INCLUDES=""
+                   ],
+                   [$MATH_LIBS]),
+    [AC_MSG_WARN(png library not available - no png.h)
+     PNG_LIBS=""
+     PNG_INCLUDES=""
+    ],
+  )
+  LIBCHECK_EPILOGUE([PNG])
+])
+
+dnl === check for JPEG support ===
+
+AC_ARG_ENABLE([jpeg],
+              AS_HELP_STRING([--disable-jpeg],
+                             [Disable detection of JPEG format support
+                              @<:@default=auto@:>@]))
+AS_IF([test "x$enable_jpeg" != "xno"], [
+  CLEAR_LIBVARS([JPEG])
+  WITHLIB_OPTION([jpeg], [JPEG])
+
+  LIBCHECK_PROLOGUE([JPEG])
+  AC_CHECK_HEADER(jpeglib.h,
+    AC_CHECK_LIB(jpeg, jpeg_set_defaults,
+                 [JPEG_LIBS="$JPEG_LIBS -ljpeg"
+                  JPEG_INCLUDES="$JPEG_INCLUDES -DWEBP_HAVE_JPEG"
+                  AC_DEFINE(WEBP_HAVE_JPEG, [1],
+                            [Set to 1 if JPEG library is installed])
+                  jpeg_support=yes
+                 ],
+                 AC_MSG_WARN(Optional jpeg library not found),
+                 [$MATH_LIBS]),
+    AC_MSG_WARN(jpeg library not available - no jpeglib.h)
+  )
+  LIBCHECK_EPILOGUE([JPEG])
+])
+
+dnl === check for TIFF support ===
+
+AC_ARG_ENABLE([tiff],
+              AS_HELP_STRING([--disable-tiff],
+                             [Disable detection of TIFF format support
+                              @<:@default=auto@:>@]))
+AS_IF([test "x$enable_tiff" != "xno"], [
+  CLEAR_LIBVARS([TIFF])
+  WITHLIB_OPTION([tiff], [TIFF])
+
+  LIBCHECK_PROLOGUE([TIFF])
+  AC_CHECK_HEADER(tiffio.h,
+    AC_CHECK_LIB(tiff, TIFFGetVersion,
+                 [TIFF_LIBS="$TIFF_LIBS -ltiff"
+                  TIFF_INCLUDES="$TIFF_INCLUDES -DWEBP_HAVE_TIFF"
+                  AC_DEFINE(WEBP_HAVE_TIFF, [1],
+                            [Set to 1 if TIFF library is installed])
+                  tiff_support=yes
+                 ],
+                 AC_MSG_WARN(Optional tiff library not found),
+                 [$MATH_LIBS]),
+    AC_MSG_WARN(tiff library not available - no tiffio.h)
+  )
+  LIBCHECK_EPILOGUE([TIFF])
+])
+
+dnl === check for GIF support ===
+
+AC_ARG_ENABLE([gif], AS_HELP_STRING([--disable-gif],
+                                    [Disable detection of GIF format support
+                                     @<:@default=auto@:>@]))
+AS_IF([test "x$enable_gif" != "xno"], [
+  CLEAR_LIBVARS([GIF])
+  WITHLIB_OPTION([gif], [GIF])
+
+  LIBCHECK_PROLOGUE([GIF])
+  AC_CHECK_HEADER(gif_lib.h,
+    AC_CHECK_LIB([gif], [DGifOpenFileHandle],
+                 [GIF_LIBS="$GIF_LIBS -lgif"
+                  AC_DEFINE(WEBP_HAVE_GIF, [1],
+                            [Set to 1 if GIF library is installed])
+                  gif_support=yes
+                 ],
+                 AC_MSG_WARN(Optional gif library not found),
+                 [$MATH_LIBS]),
+    AC_MSG_WARN(gif library not available - no gif_lib.h)
+  )
+  LIBCHECK_EPILOGUE([GIF])
+
+  if test "$gif_support" = "yes" -a \
+          "$enable_libwebpdemux" = "yes"; then
+    build_anim_diff=yes
+  else
+    AC_MSG_NOTICE(
+      [Not building anim_diff. libgif and --enable-libwebpdemux are required.])
+  fi
+
+  if test "$gif_support" = "yes" -a \
+          "$enable_libwebpmux" = "yes"; then
+    build_gif2webp=yes
+  else
+    AC_MSG_NOTICE(
+      [Not building gif2webp. libgif and --enable-libwebpmux are required.])
+  fi
+])
+AM_CONDITIONAL([BUILD_ANIMDIFF], [test "${build_anim_diff}" = "yes"])
+AM_CONDITIONAL([BUILD_GIF2WEBP], [test "${build_gif2webp}" = "yes"])
+
+if test "$enable_libwebpdemux" = "yes" -a "$enable_libwebpmux" = "yes"; then
+  build_img2webp=yes
+else
+  AC_MSG_NOTICE(
+    m4_normalize([Not building img2webp.
+                  --enable-libwebpdemux & --enable-libwebpmux are required.]))
+fi
+AM_CONDITIONAL([BUILD_IMG2WEBP], [test "${build_img2webp}" = "yes"])
+
+if test "$enable_libwebpmux" = "yes"; then
+  build_webpinfo=yes
+else
+  AC_MSG_NOTICE([Not building webpinfo. --enable-libwebpdemux is required.])
+fi
+AM_CONDITIONAL([BUILD_WEBPINFO], [test "${build_webpinfo}" = "yes"])
+
+dnl === check for WIC support ===
+
+AC_ARG_ENABLE([wic],
+              AS_HELP_STRING([--disable-wic],
+                             [Disable Windows Imaging Component (WIC) detection.
+                              @<:@default=auto@:>@]),,
+              [enable_wic=yes])
+
+case $host_os in
+mingw*)
+if test "$enable_wic" = "yes"; then
+  AC_CHECK_HEADERS([wincodec.h shlwapi.h windows.h])
+  if test "$ac_cv_header_wincodec_h" = "yes"; then
+    AC_MSG_CHECKING(for Windows Imaging Component support)
+    SAVED_LIBS=$LIBS
+    LIBS="-lshlwapi -lole32 $LIBS"
+    # match include structure from [cd]webp.c
+    wic_headers="
+      #define INITGUID
+      #define CINTERFACE
+      #define COBJMACROS
+      #define _WIN32_IE 0x500
+
+      #include <shlwapi.h>
+      #include <windows.h>
+      #include <wincodec.h>
+      "
+    # test for functions from each lib and the GUID is created properly
+    wic_main="
+      int main(void) {
+        CLSID_WICImagingFactory;
+        CoInitialize(NULL);
+        SHCreateStreamOnFile(NULL, 0, NULL);
+        return 0;
+      }
+      "
+    AC_LANG_PUSH(C)
+    AC_LINK_IFELSE(
+      [AC_LANG_SOURCE([
+         $wic_headers
+         $wic_main])],
+      [wic_support=yes],
+      [wic_support=no]
+    )
+    AC_LANG_POP
+
+    test "$wic_support" = "yes" || LIBS=$SAVED_LIBS
+    AC_MSG_RESULT(${wic_support-no})
+  fi
+fi
+esac
+
+dnl === If --enable-swap-16bit-csp is defined, add -DWEBP_SWAP_16BIT_CSP=1
+
+USE_SWAP_16BIT_CSP=""
+AC_MSG_CHECKING(if --enable-swap-16bit-csp option is specified)
+AC_ARG_ENABLE([swap-16bit-csp],
+              AS_HELP_STRING([--enable-swap-16bit-csp],
+                             [Enable byte swap for 16 bit colorspaces]))
+if test "$enable_swap_16bit_csp" = "yes"; then
+  USE_SWAP_16BIT_CSP="-DWEBP_SWAP_16BIT_CSP=1"
+fi
+AC_MSG_RESULT(${enable_swap_16bit_csp-no})
+AC_SUBST(USE_SWAP_16BIT_CSP)
+
+dnl === If --disable-near-lossless is defined, add -DWEBP_NEAR_LOSSLESS=0
+
+AC_DEFINE(WEBP_NEAR_LOSSLESS, [1], [Enable near lossless encoding])
+AC_MSG_CHECKING(if --disable-near-lossless option is specified)
+AC_ARG_ENABLE([near_lossless],
+              AS_HELP_STRING([--disable-near-lossless],
+                             [Disable near lossless encoding]),
+              [], [enable_near_lossless=yes])
+if test "$enable_near_lossless" = "no"; then
+  AC_DEFINE(WEBP_NEAR_LOSSLESS, [0], [Enable near lossless encoding])
+  AC_MSG_RESULT([yes])
+else
+  AC_MSG_RESULT([no])
+fi
+
+dnl =========================
+
+dnl Add an empty webp_libname_prefix variable for use in *.pc.in.
+AC_SUBST([webp_libname_prefix])
+AC_CONFIG_MACRO_DIR([m4])
+AC_CONFIG_HEADERS([src/webp/config.h])
+AC_CONFIG_FILES([Makefile src/Makefile man/Makefile \
+                 examples/Makefile extras/Makefile imageio/Makefile \
+                 sharpyuv/Makefile sharpyuv/libsharpyuv.pc \
+                 src/dec/Makefile src/enc/Makefile src/dsp/Makefile \
+                 src/demux/Makefile src/mux/Makefile \
+                 src/utils/Makefile \
+                 src/libwebp.pc src/libwebpdecoder.pc \
+                 src/demux/libwebpdemux.pc src/mux/libwebpmux.pc])
+
+
+AC_OUTPUT
+
+AC_MSG_NOTICE([
+WebP Configuration Summary
+--------------------------
+
+Shared libraries: ${enable_shared}
+Static libraries: ${enable_static}
+Threading support: ${enable_threading-no}
+libwebp: yes
+libwebpdecoder: ${enable_libwebpdecoder-no}
+libwebpdemux: ${enable_libwebpdemux-no}
+libwebpmux: ${enable_libwebpmux-no}
+libwebpextras: ${enable_libwebpextras-no}
+
+Tools:
+cwebp : ${enable_libwebpdemux-no}
+  Input format support
+  ====================
+  JPEG : ${jpeg_support-no}
+  PNG  : ${png_support-no}
+  TIFF : ${tiff_support-no}
+  WIC  : ${wic_support-no}
+dwebp : ${enable_libwebpdemux-no}
+  Output format support
+  =====================
+  PNG  : ${png_support-no}
+  WIC  : ${wic_support-no}
+GIF support : ${gif_support-no}
+anim_diff   : ${build_anim_diff-no}
+gif2webp    : ${build_gif2webp-no}
+img2webp    : ${build_img2webp-no}
+webpmux     : ${enable_libwebpmux-no}
+vwebp       : ${build_vwebp-no}
+webpinfo    : ${build_webpinfo-no}
+SDL support : ${sdl_support-no}
+vwebp_sdl   : ${build_vwebp_sdl-no}
+])

doc/TODO

@@ -0,0 +1,13 @@
+<louquillio@google.com>, 20111004
+
+* Determine that normative RFC 2119 terms (MUST, SHOULD, MAY, etc.) are
+  truly intended in all cases where capitalized.
+
+* Several passages could be made clearer.
+
+  * Overall edit for scope.  Portions are phrased as an introduction to
+    the 0.1.3 RIFF container additions, rather than a holistic guide to
+    WebP.
+
+  * To wit, suggest s/[spec|specification]/guide/g .  "Spec" can imply a
+    standards track; in any case it's too formal for a work in progress.

doc/api.md

@@ -0,0 +1,385 @@
+# WebP APIs
+
+## Encoding API
+
+The main encoding functions are available in the header src/webp/encode.h
+
+The ready-to-use ones are:
+
+```c
+size_t WebPEncodeRGB(const uint8_t* rgb, int width, int height, int stride,
+                     float quality_factor, uint8_t** output);
+size_t WebPEncodeBGR(const uint8_t* bgr, int width, int height, int stride,
+                     float quality_factor, uint8_t** output);
+size_t WebPEncodeRGBA(const uint8_t* rgba, int width, int height, int stride,
+                      float quality_factor, uint8_t** output);
+size_t WebPEncodeBGRA(const uint8_t* bgra, int width, int height, int stride,
+                      float quality_factor, uint8_t** output);
+```
+
+They will convert raw RGB samples to a WebP data. The only control supplied is
+the quality factor.
+
+There are some variants for using the lossless format:
+
+```c
+size_t WebPEncodeLosslessRGB(const uint8_t* rgb, int width, int height,
+                             int stride, uint8_t** output);
+size_t WebPEncodeLosslessBGR(const uint8_t* bgr, int width, int height,
+                             int stride, uint8_t** output);
+size_t WebPEncodeLosslessRGBA(const uint8_t* rgba, int width, int height,
+                              int stride, uint8_t** output);
+size_t WebPEncodeLosslessBGRA(const uint8_t* bgra, int width, int height,
+                              int stride, uint8_t** output);
+```
+
+Of course in this case, no quality factor is needed since the compression occurs
+without loss of the input values, at the expense of larger output sizes.
+
+### Advanced encoding API
+
+A more advanced API is based on the WebPConfig and WebPPicture structures.
+
+WebPConfig contains the encoding settings and is not tied to a particular
+picture. WebPPicture contains input data, on which some WebPConfig will be used
+for compression. The encoding flow looks like:
+
+```c
+#include <webp/encode.h>
+
+// Setup a config, starting form a preset and tuning some additional
+// parameters
+WebPConfig config;
+if (!WebPConfigPreset(&config, WEBP_PRESET_PHOTO, quality_factor)) {
+  return 0;   // version error
+}
+// ... additional tuning
+config.sns_strength = 90;
+config.filter_sharpness = 6;
+config_error = WebPValidateConfig(&config);  // not mandatory, but useful
+
+// Setup the input data
+WebPPicture pic;
+if (!WebPPictureInit(&pic)) {
+  return 0;  // version error
+}
+pic.width = width;
+pic.height = height;
+// allocated picture of dimension width x height
+if (!WebPPictureAlloc(&pic)) {
+  return 0;   // memory error
+}
+// at this point, 'pic' has been initialized as a container,
+// and can receive the Y/U/V samples.
+// Alternatively, one could use ready-made import functions like
+// WebPPictureImportRGB(), which will take care of memory allocation.
+// In any case, past this point, one will have to call
+// WebPPictureFree(&pic) to reclaim memory.
+
+// Set up a byte-output write method. WebPMemoryWriter, for instance.
+WebPMemoryWriter wrt;
+WebPMemoryWriterInit(&wrt);     // initialize 'wrt'
+
+pic.writer = MyFileWriter;
+pic.custom_ptr = my_opaque_structure_to_make_MyFileWriter_work;
+
+// Compress!
+int ok = WebPEncode(&config, &pic);   // ok = 0 => error occurred!
+WebPPictureFree(&pic);  // must be called independently of the 'ok' result.
+
+// output data should have been handled by the writer at that point.
+// -> compressed data is the memory buffer described by wrt.mem / wrt.size
+
+// deallocate the memory used by compressed data
+WebPMemoryWriterClear(&wrt);
+```
+
+## Decoding API
+
+This is mainly just one function to call:
+
+```c
+#include "webp/decode.h"
+uint8_t* WebPDecodeRGB(const uint8_t* data, size_t data_size,
+                       int* width, int* height);
+```
+
+Please have a look at the file src/webp/decode.h for the details. There are
+variants for decoding in BGR/RGBA/ARGB/BGRA order, along with decoding to raw
+Y'CbCr samples. One can also decode the image directly into a pre-allocated
+buffer.
+
+To detect a WebP file and gather the picture's dimensions, the function:
+
+```c
+int WebPGetInfo(const uint8_t* data, size_t data_size,
+                int* width, int* height);
+```
+
+is supplied. No decoding is involved when using it.
+
+### Incremental decoding API
+
+In the case when data is being progressively transmitted, pictures can still be
+incrementally decoded using a slightly more complicated API. Decoder state is
+stored into an instance of the WebPIDecoder object. This object can be created
+with the purpose of decoding either RGB or Y'CbCr samples. For instance:
+
+```c
+WebPDecBuffer buffer;
+WebPInitDecBuffer(&buffer);
+buffer.colorspace = MODE_BGR;
+...
+WebPIDecoder* idec = WebPINewDecoder(&buffer);
+```
+
+As data is made progressively available, this incremental-decoder object can be
+used to decode the picture further. There are two (mutually exclusive) ways to
+pass freshly arrived data:
+
+either by appending the fresh bytes:
+
+```c
+WebPIAppend(idec, fresh_data, size_of_fresh_data);
+```
+
+or by just mentioning the new size of the transmitted data:
+
+```c
+WebPIUpdate(idec, buffer, size_of_transmitted_buffer);
+```
+
+Note that 'buffer' can be modified between each call to WebPIUpdate, in
+particular when the buffer is resized to accommodate larger data.
+
+These functions will return the decoding status: either VP8_STATUS_SUSPENDED if
+decoding is not finished yet or VP8_STATUS_OK when decoding is done. Any other
+status is an error condition.
+
+The 'idec' object must always be released (even upon an error condition) by
+calling: WebPDelete(idec).
+
+To retrieve partially decoded picture samples, one must use the corresponding
+method: WebPIDecGetRGB or WebPIDecGetYUVA. It will return the last displayable
+pixel row.
+
+Lastly, note that decoding can also be performed into a pre-allocated pixel
+buffer. This buffer must be passed when creating a WebPIDecoder, calling
+WebPINewRGB() or WebPINewYUVA().
+
+Please have a look at the src/webp/decode.h header for further details.
+
+### Advanced Decoding API
+
+WebP decoding supports an advanced API which provides on-the-fly cropping and
+rescaling, something of great usefulness on memory-constrained environments like
+mobile phones. Basically, the memory usage will scale with the output's size,
+not the input's, when one only needs a quick preview or a zoomed in portion of
+an otherwise too-large picture. Some CPU can be saved too, incidentally.
+
+```c
+// A) Init a configuration object
+WebPDecoderConfig config;
+CHECK(WebPInitDecoderConfig(&config));
+
+// B) optional: retrieve the bitstream's features.
+CHECK(WebPGetFeatures(data, data_size, &config.input) == VP8_STATUS_OK);
+
+// C) Adjust 'config' options, if needed
+config.options.no_fancy_upsampling = 1;
+config.options.use_scaling = 1;
+config.options.scaled_width = scaledWidth();
+config.options.scaled_height = scaledHeight();
+// etc.
+
+// D) Specify 'config' output options for specifying output colorspace.
+// Optionally the external image decode buffer can also be specified.
+config.output.colorspace = MODE_BGRA;
+// Optionally, the config.output can be pointed to an external buffer as
+// well for decoding the image. This externally supplied memory buffer
+// should be big enough to store the decoded picture.
+config.output.u.RGBA.rgba = (uint8_t*) memory_buffer;
+config.output.u.RGBA.stride = scanline_stride;
+config.output.u.RGBA.size = total_size_of_the_memory_buffer;
+config.output.is_external_memory = 1;
+
+// E) Decode the WebP image. There are two variants w.r.t decoding image.
+// The first one (E.1) decodes the full image and the second one (E.2) is
+// used to incrementally decode the image using small input buffers.
+// Any one of these steps can be used to decode the WebP image.
+
+// E.1) Decode full image.
+CHECK(WebPDecode(data, data_size, &config) == VP8_STATUS_OK);
+
+// E.2) Decode image incrementally.
+WebPIDecoder* const idec = WebPIDecode(NULL, NULL, &config);
+CHECK(idec != NULL);
+while (bytes_remaining > 0) {
+  VP8StatusCode status = WebPIAppend(idec, input, bytes_read);
+  if (status == VP8_STATUS_OK || status == VP8_STATUS_SUSPENDED) {
+    bytes_remaining -= bytes_read;
+  } else {
+    break;
+  }
+}
+WebPIDelete(idec);
+
+// F) Decoded image is now in config.output (and config.output.u.RGBA).
+// It can be saved, displayed or otherwise processed.
+
+// G) Reclaim memory allocated in config's object. It's safe to call
+// this function even if the memory is external and wasn't allocated
+// by WebPDecode().
+WebPFreeDecBuffer(&config.output);
+```
+
+## WebP Mux
+
+WebPMux is a set of two libraries 'Mux' and 'Demux' for creation, extraction and
+manipulation of an extended format WebP file, which can have features like color
+profile, metadata and animation. Reference command-line tools `webpmux` and
+`vwebp` as well as the WebP container specification
+'doc/webp-container-spec.txt' are also provided in this package, see the
+[tools documentation](tools.md).
+
+### Mux API
+
+The Mux API contains methods for adding data to and reading data from WebP
+files. This API currently supports XMP/EXIF metadata, ICC profile and animation.
+Other features may be added in subsequent releases.
+
+Example#1 (pseudo code): Creating a WebPMux object with image data, color
+profile and XMP metadata.
+
+```c
+int copy_data = 0;
+WebPMux* mux = WebPMuxNew();
+// ... (Prepare image data).
+WebPMuxSetImage(mux, &image, copy_data);
+// ... (Prepare ICC profile data).
+WebPMuxSetChunk(mux, "ICCP", &icc_profile, copy_data);
+// ... (Prepare XMP metadata).
+WebPMuxSetChunk(mux, "XMP ", &xmp, copy_data);
+// Get data from mux in WebP RIFF format.
+WebPMuxAssemble(mux, &output_data);
+WebPMuxDelete(mux);
+// ... (Consume output_data; e.g. write output_data.bytes to file).
+WebPDataClear(&output_data);
+```
+
+Example#2 (pseudo code): Get image and color profile data from a WebP file.
+
+```c
+int copy_data = 0;
+// ... (Read data from file).
+WebPMux* mux = WebPMuxCreate(&data, copy_data);
+WebPMuxGetFrame(mux, 1, &image);
+// ... (Consume image; e.g. call WebPDecode() to decode the data).
+WebPMuxGetChunk(mux, "ICCP", &icc_profile);
+// ... (Consume icc_profile).
+WebPMuxDelete(mux);
+free(data);
+```
+
+For a detailed Mux API reference, please refer to the header file
+(src/webp/mux.h).
+
+### Demux API
+
+The Demux API enables extraction of images and extended format data from WebP
+files. This API currently supports reading of XMP/EXIF metadata, ICC profile and
+animated images. Other features may be added in subsequent releases.
+
+Code example: Demuxing WebP data to extract all the frames, ICC profile and
+EXIF/XMP metadata.
+
+```c
+WebPDemuxer* demux = WebPDemux(&webp_data);
+uint32_t width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH);
+uint32_t height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT);
+// ... (Get information about the features present in the WebP file).
+uint32_t flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS);
+
+// ... (Iterate over all frames).
+WebPIterator iter;
+if (WebPDemuxGetFrame(demux, 1, &iter)) {
+  do {
+    // ... (Consume 'iter'; e.g. Decode 'iter.fragment' with WebPDecode(),
+    // ... and get other frame properties like width, height, offsets etc.
+    // ... see 'struct WebPIterator' below for more info).
+  } while (WebPDemuxNextFrame(&iter));
+  WebPDemuxReleaseIterator(&iter);
+}
+
+// ... (Extract metadata).
+WebPChunkIterator chunk_iter;
+if (flags & ICCP_FLAG) WebPDemuxGetChunk(demux, "ICCP", 1, &chunk_iter);
+// ... (Consume the ICC profile in 'chunk_iter.chunk').
+WebPDemuxReleaseChunkIterator(&chunk_iter);
+if (flags & EXIF_FLAG) WebPDemuxGetChunk(demux, "EXIF", 1, &chunk_iter);
+// ... (Consume the EXIF metadata in 'chunk_iter.chunk').
+WebPDemuxReleaseChunkIterator(&chunk_iter);
+if (flags & XMP_FLAG) WebPDemuxGetChunk(demux, "XMP ", 1, &chunk_iter);
+// ... (Consume the XMP metadata in 'chunk_iter.chunk').
+WebPDemuxReleaseChunkIterator(&chunk_iter);
+WebPDemuxDelete(demux);
+```
+
+For a detailed Demux API reference, please refer to the header file
+(src/webp/demux.h).
+
+## AnimEncoder API
+
+The AnimEncoder API can be used to create animated WebP images.
+
+Code example:
+
+```c
+WebPAnimEncoderOptions enc_options;
+WebPAnimEncoderOptionsInit(&enc_options);
+// ... (Tune 'enc_options' as needed).
+WebPAnimEncoder* enc = WebPAnimEncoderNew(width, height, &enc_options);
+while(<there are more frames>) {
+  WebPConfig config;
+  WebPConfigInit(&config);
+  // ... (Tune 'config' as needed).
+  WebPAnimEncoderAdd(enc, frame, duration, &config);
+}
+WebPAnimEncoderAssemble(enc, webp_data);
+WebPAnimEncoderDelete(enc);
+// ... (Write the 'webp_data' to a file, or re-mux it further).
+```
+
+For a detailed AnimEncoder API reference, please refer to the header file
+(src/webp/mux.h).
+
+## AnimDecoder API
+
+This AnimDecoder API allows decoding (possibly) animated WebP images.
+
+Code Example:
+
+```c
+WebPAnimDecoderOptions dec_options;
+WebPAnimDecoderOptionsInit(&dec_options);
+// Tune 'dec_options' as needed.
+WebPAnimDecoder* dec = WebPAnimDecoderNew(webp_data, &dec_options);
+WebPAnimInfo anim_info;
+WebPAnimDecoderGetInfo(dec, &anim_info);
+for (uint32_t i = 0; i < anim_info.loop_count; ++i) {
+  while (WebPAnimDecoderHasMoreFrames(dec)) {
+    uint8_t* buf;
+    int timestamp;
+    WebPAnimDecoderGetNext(dec, &buf, &timestamp);
+    // ... (Render 'buf' based on 'timestamp').
+    // ... (Do NOT free 'buf', as it is owned by 'dec').
+  }
+  WebPAnimDecoderReset(dec);
+}
+const WebPDemuxer* demuxer = WebPAnimDecoderGetDemuxer(dec);
+// ... (Do something using 'demuxer'; e.g. get EXIF/XMP/ICC data).
+WebPAnimDecoderDelete(dec);
+```
+
+For a detailed AnimDecoder API reference, please refer to the header file
+(src/webp/demux.h).

doc/building.md

@@ -0,0 +1,213 @@
+# Building
+
+## Windows build
+
+By running:
+
+```batch
+nmake /f Makefile.vc CFG=release-static RTLIBCFG=static OBJDIR=output
+```
+
+the directory `output\release-static\(x64|x86)\bin` will contain the tools
+cwebp.exe and dwebp.exe. The directory `output\release-static\(x64|x86)\lib`
+will contain the libwebp static library. The target architecture (x86/x64) is
+detected by Makefile.vc from the Visual Studio compiler (cl.exe) available in
+the system path.
+
+## Unix build using makefile.unix
+
+On platforms with GNU tools installed (gcc and make), running
+
+```shell
+make -f makefile.unix
+```
+
+will build the binaries examples/cwebp and examples/dwebp, along with the static
+library src/libwebp.a. No system-wide installation is supplied, as this is a
+simple alternative to the full installation system based on the autoconf tools
+(see below). Please refer to makefile.unix for additional details and
+customizations.
+
+## Using autoconf tools
+
+Prerequisites: a compiler (e.g., gcc), make, autoconf, automake, libtool.
+
+On a Debian-like system the following should install everything you need for a
+minimal build:
+
+```shell
+$ sudo apt-get install gcc make autoconf automake libtool
+```
+
+When building from git sources, you will need to run autogen.sh to generate the
+configure script.
+
+```shell
+./configure
+make
+make install
+```
+
+should be all you need to have the following files
+
+```
+/usr/local/include/webp/decode.h
+/usr/local/include/webp/encode.h
+/usr/local/include/webp/types.h
+/usr/local/lib/libwebp.*
+/usr/local/bin/cwebp
+/usr/local/bin/dwebp
+```
+
+installed.
+
+Note: A decode-only library, libwebpdecoder, is available using the
+`--enable-libwebpdecoder` flag. The encode library is built separately and can
+be installed independently using a minor modification in the corresponding
+Makefile.am configure files (see comments there). See `./configure --help` for
+more options.
+
+## Building for MIPS Linux
+
+MIPS Linux toolchain stable available releases can be found at:
+https://community.imgtec.com/developers/mips/tools/codescape-mips-sdk/available-releases/
+
+```shell
+# Add toolchain to PATH
+export PATH=$PATH:/path/to/toolchain/bin
+
+# 32-bit build for mips32r5 (p5600)
+HOST=mips-mti-linux-gnu
+MIPS_CFLAGS="-O3 -mips32r5 -mabi=32 -mtune=p5600 -mmsa -mfp64 \
+  -msched-weight -mload-store-pairs -fPIE"
+MIPS_LDFLAGS="-mips32r5 -mabi=32 -mmsa -mfp64 -pie"
+
+# 64-bit build for mips64r6 (i6400)
+HOST=mips-img-linux-gnu
+MIPS_CFLAGS="-O3 -mips64r6 -mabi=64 -mtune=i6400 -mmsa -mfp64 \
+  -msched-weight -mload-store-pairs -fPIE"
+MIPS_LDFLAGS="-mips64r6 -mabi=64 -mmsa -mfp64 -pie"
+
+./configure --host=${HOST} --build=`config.guess` \
+  CC="${HOST}-gcc -EL" \
+  CFLAGS="$MIPS_CFLAGS" \
+  LDFLAGS="$MIPS_LDFLAGS"
+make
+make install
+```
+
+## CMake
+
+With CMake, you can compile libwebp, cwebp, dwebp, gif2webp, img2webp, webpinfo
+and the JS bindings.
+
+Prerequisites: a compiler (e.g., gcc with autotools) and CMake.
+
+On a Debian-like system the following should install everything you need for a
+minimal build:
+
+```shell
+$ sudo apt-get install build-essential cmake
+```
+
+When building from git sources, you will need to run cmake to generate the
+makefiles.
+
+```shell
+mkdir build && cd build && cmake ../
+make
+make install
+```
+
+If you also want any of the executables, you will need to enable them through
+CMake, e.g.:
+
+```shell
+cmake -DWEBP_BUILD_CWEBP=ON -DWEBP_BUILD_DWEBP=ON ../
+```
+
+or through your favorite interface (like ccmake or cmake-qt-gui).
+
+Use option `-DWEBP_UNICODE=ON` for Unicode support on Windows (with chcp 65001).
+
+Finally, once installed, you can also use WebP in your CMake project by doing:
+
+```cmake
+find_package(WebP)
+```
+
+which will define the CMake variables WebP_INCLUDE_DIRS and WebP_LIBRARIES.
+
+## Gradle
+
+The support for Gradle is minimal: it only helps you compile libwebp, cwebp and
+dwebp and webpmux_example.
+
+Prerequisites: a compiler (e.g., gcc with autotools) and gradle.
+
+On a Debian-like system the following should install everything you need for a
+minimal build:
+
+```shell
+$ sudo apt-get install build-essential gradle
+```
+
+When building from git sources, you will need to run the Gradle wrapper with the
+appropriate target, e.g. :
+
+```shell
+./gradlew buildAllExecutables
+```
+
+## SWIG bindings
+
+To generate language bindings from swig/libwebp.swig at least swig-1.3
+(http://www.swig.org) is required.
+
+Currently the following functions are mapped:
+
+Decode:
+
+```
+WebPGetDecoderVersion
+WebPGetInfo
+WebPDecodeRGBA
+WebPDecodeARGB
+WebPDecodeBGRA
+WebPDecodeBGR
+WebPDecodeRGB
+```
+
+Encode:
+
+```
+WebPGetEncoderVersion
+WebPEncodeRGBA
+WebPEncodeBGRA
+WebPEncodeRGB
+WebPEncodeBGR
+WebPEncodeLosslessRGBA
+WebPEncodeLosslessBGRA
+WebPEncodeLosslessRGB
+WebPEncodeLosslessBGR
+```
+
+See also the [swig documentation](../swig/README.md) for more detailed build
+instructions and usage examples.
+
+### Java bindings
+
+To build the swig-generated JNI wrapper code at least JDK-1.5 (or equivalent) is
+necessary for enum support. The output is intended to be a shared object / DLL
+that can be loaded via `System.loadLibrary("webp_jni")`.
+
+### Python bindings
+
+To build the swig-generated Python extension code at least Python 2.6 is
+required. Python < 2.6 may build with some minor changes to libwebp.swig or the
+generated code, but is untested.
+
+## Javascript decoder
+
+Libwebp can be compiled into a JavaScript decoder using Emscripten and CMake.
+See the [corresponding documentation](../README.md)

doc/specs_generation.md

@@ -0,0 +1,26 @@
+# Generate libwebp Container Spec Docs from Text Source
+
+HTML generation requires [kramdown](https://kramdown.gettalong.org/), easily
+installed as a [rubygem](https://rubygems.org/). Rubygems installation should
+satisfy dependencies automatically.
+
+HTML generation can then be done from the project root:
+
+```shell
+$ kramdown doc/webp-container-spec.txt --template doc/template.html > \
+  doc/output/webp-container-spec.html
+```
+
+kramdown can optionally syntax highlight code blocks, using
+[CodeRay](https://github.com/rubychan/coderay), a dependency of kramdown that
+rubygems will install automatically. The following will apply inline CSS
+styling; an external stylesheet is not needed.
+
+```shell
+$ kramdown doc/webp-lossless-bitstream-spec.txt --template \
+  doc/template.html --coderay-css style --coderay-line-numbers ' ' \
+  --coderay-default-lang c > \
+  doc/output/webp-lossless-bitstream-spec.html
+```
+
+Optimally, use kramdown 0.13.7 or newer if syntax highlighting desired.

doc/template.html

@@ -0,0 +1,94 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <title>WebP Container Specification</title>
+  <meta name="generator" content="kramdown <%= ::Kramdown::VERSION %>" />
+  <style type="text/css">
+  body {
+    color: #000;
+    background-color: #fff;
+    margin: 10%;
+    font-family: "Liberation Sans", "DejaVu Sans", "Bitstream Vera Sans", Arial, sans-serif;
+    line-height: 1.4;
+  }
+  h2 {
+    border-bottom: 1px solid #ccc;
+    padding-bottom: 0;
+  }
+  table {
+    border-collapse: collapse;
+  }
+  th, td {
+    border: 1px solid #999;
+    padding: .5em .7em;;
+  }
+  th {
+    color: #fff;
+    background-color: #000;
+  }
+  td {
+  }
+  hr {
+  }
+  code {
+    color: #000;
+    background-color: #f7f7f7;
+    padding: 0 3px;
+    font-family: "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", Consolata, monospace;
+  }
+  pre {
+    background-color: #f7f7f7;
+    padding: 1em;
+    border: 1px solid #ccc;
+    width: 42em;
+    overflow: auto;
+    font-family: "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", Consolata, monospace;
+  }
+  pre code {
+    background-color: #f7f7f7;
+    padding: 0; /* Only want padding on inline code, not blocks */
+  }
+  pre.terminal {
+    color: #fff;
+    background-color: #000;
+    border: 1px solid #ccc;
+    max-height: 30em;
+  }
+  pre.terminal code {
+    color: #fff;
+    background-color: #000;
+    font-size: smaller;
+  }
+  #markdown-toc ul {
+    list-style-type: disc;
+  }
+  ul#markdown-toc {
+    margin-top: -1em;
+    visibility: hidden;
+    -webkit-padding-start: 0;
+  }
+  ul#markdown-toc ul {
+    visibility: visible;
+  }
+  ul#markdown-toc ul ul{
+    visibility: visible;
+  }
+  ul#markdown-toc + hr {
+    margin-bottom: 4em;
+  }
+  ol ol { /* Format nested ordered lists */
+    list-style-type: lower-alpha;
+  }
+  dt {
+    font-style: italic;
+    font-weight: bold;
+  }
+  .caption {
+  }
+  </style>
+</head>
+<body>
+<%= @body %>
+</body>
+</html>

doc/tools.md

@@ -0,0 +1,516 @@
+# WebP tools
+
+## Encoding tool
+
+The examples/ directory contains tools for encoding (cwebp) and decoding (dwebp)
+images.
+
+The easiest use should look like:
+
+```shell
+cwebp input.png -q 80 -o output.webp
+```
+
+which will convert the input file to a WebP file using a quality factor of 80 on
+a 0->100 scale (0 being the lowest quality, 100 being the best. Default value is
+75).
+
+You might want to try the `-lossless` flag too, which will compress the source
+(in RGBA format) without any loss. The `-q` quality parameter will in this case
+control the amount of processing time spent trying to make the output file as
+small as possible.
+
+A longer list of options is available using the `-longhelp` command line flag:
+
+```shell
+> cwebp -longhelp
+Usage:
+ cwebp [-preset <...>] [options] in_file [-o out_file]
+```
+
+If input size (-s) for an image is not specified, it is assumed to be a PNG,
+JPEG, TIFF or WebP file. Note: Animated PNG and WebP files are not supported.
+
+Options:
+
+```
+-h / -help ............. short help
+-H / -longhelp ......... long help
+-q <float> ............. quality factor (0:small..100:big), default=75
+-alpha_q <int> ......... transparency-compression quality (0..100),
+                         default=100
+-preset <string> ....... preset setting, one of:
+                          default, photo, picture,
+                          drawing, icon, text
+   -preset must come first, as it overwrites other parameters
+-z <int> ............... activates lossless preset with given
+                         level in [0:fast, ..., 9:slowest]
+
+-m <int> ............... compression method (0=fast, 6=slowest), default=4
+-segments <int> ........ number of segments to use (1..4), default=4
+-size <int> ............ target size (in bytes)
+-psnr <float> .......... target PSNR (in dB. typically: 42)
+
+-s <int> <int> ......... input size (width x height) for YUV
+-sns <int> ............. spatial noise shaping (0:off, 100:max), default=50
+-f <int> ............... filter strength (0=off..100), default=60
+-sharpness <int> ....... filter sharpness (0:most .. 7:least sharp), default=0
+-strong ................ use strong filter instead of simple (default)
+-nostrong .............. use simple filter instead of strong
+-sharp_yuv ............. use sharper (and slower) RGB->YUV conversion
+-partition_limit <int> . limit quality to fit the 512k limit on
+                         the first partition (0=no degradation ... 100=full)
+-pass <int> ............ analysis pass number (1..10)
+-qrange <min> <max> .... specifies the permissible quality range
+                         (default: 0 100)
+-crop <x> <y> <w> <h> .. crop picture with the given rectangle
+-resize <w> <h> ........ resize picture (*after* any cropping)
+-mt .................... use multi-threading if available
+-low_memory ............ reduce memory usage (slower encoding)
+-map <int> ............. print map of extra info
+-print_psnr ............ prints averaged PSNR distortion
+-print_ssim ............ prints averaged SSIM distortion
+-print_lsim ............ prints local-similarity distortion
+-d <file.pgm> .......... dump the compressed output (PGM file)
+-alpha_method <int> .... transparency-compression method (0..1), default=1
+-alpha_filter <string> . predictive filtering for alpha plane,
+                         one of: none, fast (default) or best
+-exact ................. preserve RGB values in transparent area, default=off
+-blend_alpha <hex> ..... blend colors against background color
+                         expressed as RGB values written in
+                         hexadecimal, e.g. 0xc0e0d0 for red=0xc0
+                         green=0xe0 and blue=0xd0
+-noalpha ............... discard any transparency information
+-lossless .............. encode image losslessly, default=off
+-near_lossless <int> ... use near-lossless image preprocessing
+                         (0..100=off), default=100
+-hint <string> ......... specify image characteristics hint,
+                         one of: photo, picture or graph
+
+-metadata <string> ..... comma separated list of metadata to
+                         copy from the input to the output if present.
+                         Valid values: all, none (default), exif, icc, xmp
+
+-short ................. condense printed message
+-quiet ................. don't print anything
+-version ............... print version number and exit
+-noasm ................. disable all assembly optimizations
+-v ..................... verbose, e.g. print encoding/decoding times
+-progress .............. report encoding progress
+```
+
+Experimental Options:
+
+```
+-jpeg_like ............. roughly match expected JPEG size
+-af .................... auto-adjust filter strength
+-pre <int> ............. pre-processing filter
+```
+
+The main options you might want to try in order to further tune the visual
+quality are:
+
+-preset -sns -f -m
+
+Namely:
+
+*   `preset` will set up a default encoding configuration targeting a particular
+    type of input. It should appear first in the list of options, so that
+    subsequent options can take effect on top of this preset. Default value is
+    'default'.
+*   `sns` will progressively turn on (when going from 0 to 100) some additional
+    visual optimizations (like: segmentation map re-enforcement). This option
+    will balance the bit allocation differently. It tries to take bits from the
+    "easy" parts of the picture and use them in the "difficult" ones instead.
+    Usually, raising the sns value (at fixed -q value) leads to larger files,
+    but with better quality. Typical value is around '75'.
+*   `f` option directly links to the filtering strength used by the codec's
+    in-loop processing. The higher the value, the smoother the highly-compressed
+    area will look. This is particularly useful when aiming at very small files.
+    Typical values are around 20-30. Note that using the option
+    -strong/-nostrong will change the type of filtering. Use "-f 0" to turn
+    filtering off.
+*   `m` controls the trade-off between encoding speed and quality. Default is 4.
+    You can try -m 5 or -m 6 to explore more (time-consuming) encoding
+    possibilities. A lower value will result in faster encoding at the expense
+    of quality.
+
+## Decoding tool
+
+There is a decoding sample in examples/dwebp.c which will take a .webp file and
+decode it to a PNG image file (amongst other formats). This is simply to
+demonstrate the use of the API. You can verify the file test.webp decodes to
+exactly the same as test_ref.ppm by using:
+
+```shell
+cd examples
+./dwebp test.webp -ppm -o test.ppm
+diff test.ppm test_ref.ppm
+```
+
+The full list of options is available using -h:
+
+```shell
+> dwebp -h
+Usage: dwebp in_file [options] [-o out_file]
+```
+
+Decodes the WebP image file to PNG format [Default]. Note: Animated WebP files
+are not supported.
+
+Use following options to convert into alternate image formats:
+
+```
+-pam ......... save the raw RGBA samples as a color PAM
+-ppm ......... save the raw RGB samples as a color PPM
+-bmp ......... save as uncompressed BMP format
+-tiff ........ save as uncompressed TIFF format
+-pgm ......... save the raw YUV samples as a grayscale PGM
+               file with IMC4 layout
+-yuv ......... save the raw YUV samples in flat layout
+```
+
+Other options are:
+
+```
+-version ..... print version number and exit
+-nofancy ..... don't use the fancy YUV420 upscaler
+-nofilter .... disable in-loop filtering
+-nodither .... disable dithering
+-dither <d> .. dithering strength (in 0..100)
+-alpha_dither  use alpha-plane dithering if needed
+-mt .......... use multi-threading
+-crop <x> <y> <w> <h> ... crop output with the given rectangle
+-resize <w> <h> ......... resize output (*after* any cropping)
+-flip ........ flip the output vertically
+-alpha ....... only save the alpha plane
+-incremental . use incremental decoding (useful for tests)
+-h ........... this help message
+-v ........... verbose (e.g. print encoding/decoding times)
+-quiet ....... quiet mode, don't print anything
+-noasm ....... disable all assembly optimizations
+```
+
+## WebP file analysis tool
+
+`webpinfo` can be used to print out the chunk level structure and bitstream
+header information of WebP files. It can also check if the files are of valid
+WebP format.
+
+Usage:
+
+```shell
+webpinfo [options] in_files
+```
+
+Note: there could be multiple input files; options must come before input files.
+
+Options:
+
+```
+-version ........... Print version number and exit.
+-quiet ............. Do not show chunk parsing information.
+-diag .............. Show parsing error diagnosis.
+-summary ........... Show chunk stats summary.
+-bitstream_info .... Parse bitstream header.
+```
+
+## Visualization tool
+
+There's a little self-serve visualization tool called 'vwebp' under the
+examples/ directory. It uses OpenGL to open a simple drawing window and show a
+decoded WebP file. It's not yet integrated in the automake build system, but you
+can try to manually compile it using the recommendations below.
+
+Usage:
+
+```shell
+vwebp in_file [options]
+```
+
+Decodes the WebP image file and visualize it using OpenGL
+
+Options are:
+
+```
+-version ..... print version number and exit
+-noicc ....... don't use the icc profile if present
+-nofancy ..... don't use the fancy YUV420 upscaler
+-nofilter .... disable in-loop filtering
+-dither <int>  dithering strength (0..100), default=50
+-noalphadither disable alpha plane dithering
+-usebgcolor .. display background color
+-mt .......... use multi-threading
+-info ........ print info
+-h ........... this help message
+```
+
+Keyboard shortcuts:
+
+```
+'c' ................ toggle use of color profile
+'b' ................ toggle background color display
+'i' ................ overlay file information
+'d' ................ disable blending & disposal (debug)
+'q' / 'Q' / ESC .... quit
+```
+
+### Building
+
+Prerequisites:
+
+1.  OpenGL & OpenGL Utility Toolkit (GLUT)
+
+    Linux: `sudo apt-get install freeglut3-dev mesa-common-dev`
+
+    Mac + Xcode: These libraries should be available in the OpenGL / GLUT
+    frameworks.
+
+    Windows: http://freeglut.sourceforge.net/index.php#download
+
+2.  (Optional) qcms (Quick Color Management System)
+
+    1.  Download qcms from Mozilla / Chromium:
+        https://hg.mozilla.org/mozilla-central/file/0e7639e3bdfb/gfx/qcms
+        https://source.chromium.org/chromium/chromium/src/+/main:third_party/qcms/;drc=d4a2f8e1ed461d8fc05ed88d1ae2dc94c9773825
+    2.  Build and archive the source files as libqcms.a / qcms.lib
+    3.  Update makefile.unix / Makefile.vc
+        1.  Define WEBP_HAVE_QCMS
+        2.  Update include / library paths to reference the qcms directory.
+
+Build using makefile.unix / Makefile.vc:
+
+```shell
+$ make -f makefile.unix examples/vwebp
+> nmake /f Makefile.vc CFG=release-static \
+    ../obj/x64/release-static/bin/vwebp.exe
+```
+
+## Animation creation tool
+
+The utility `img2webp` can turn a sequence of input images (PNG, JPEG, ...) into
+an animated WebP file. It offers fine control over duration, encoding modes,
+etc.
+
+Usage:
+
+```shell
+img2webp [file_options] [[frame_options] frame_file]... [-o webp_file]
+```
+
+File-level options (only used at the start of compression):
+
+```
+-min_size ............ minimize size
+-kmax <int> .......... maximum number of frame between key-frames
+                        (0=only keyframes)
+-kmin <int> .......... minimum number of frame between key-frames
+                        (0=disable key-frames altogether)
+-mixed ............... use mixed lossy/lossless automatic mode
+-near_lossless <int> . use near-lossless image preprocessing
+                       (0..100=off), default=100
+-sharp_yuv ........... use sharper (and slower) RGB->YUV conversion
+                       (lossy only)
+-loop <int> .......... loop count (default: 0, = infinite loop)
+-v ................... verbose mode
+-h ................... this help
+-version ............. print version number and exit
+```
+
+Per-frame options (only used for subsequent images input):
+
+```
+-d <int> ............. frame duration in ms (default: 100)
+-lossless  ........... use lossless mode (default)
+-lossy ... ........... use lossy mode
+-q <float> ........... quality
+-m <int> ............. method to use
+```
+
+example: `img2webp -loop 2 in0.png -lossy in1.jpg -d 80 in2.tiff -o out.webp`
+
+Note: if a single file name is passed as the argument, the arguments will be
+tokenized from this file. The file name must not start with the character '-'.
+
+## Animated GIF conversion
+
+Animated GIF files can be converted to WebP files with animation using the
+gif2webp utility available under examples/. The files can then be viewed using
+vwebp.
+
+Usage:
+
+```shell
+gif2webp [options] gif_file -o webp_file
+```
+
+Options:
+
+```
+-h / -help ............. this help
+-lossy ................. encode image using lossy compression
+-mixed ................. for each frame in the image, pick lossy
+                         or lossless compression heuristically
+-q <float> ............. quality factor (0:small..100:big)
+-m <int> ............... compression method (0=fast, 6=slowest)
+-min_size .............. minimize output size (default:off)
+                         lossless compression by default; can be
+                         combined with -q, -m, -lossy or -mixed
+                         options
+-kmin <int> ............ min distance between key frames
+-kmax <int> ............ max distance between key frames
+-f <int> ............... filter strength (0=off..100)
+-metadata <string> ..... comma separated list of metadata to
+                         copy from the input to the output if present
+                         Valid values: all, none, icc, xmp (default)
+-loop_compatibility .... use compatibility mode for Chrome
+                         version prior to M62 (inclusive)
+-mt .................... use multi-threading if available
+
+-version ............... print version number and exit
+-v ..................... verbose
+-quiet ................. don't print anything
+```
+
+### Building
+
+With the libgif development files installed, gif2webp can be built using
+makefile.unix:
+
+```shell
+$ make -f makefile.unix examples/gif2webp
+```
+
+or using autoconf:
+
+```shell
+$ ./configure --enable-everything
+$ make
+```
+
+## Comparison of animated images
+
+Test utility anim_diff under examples/ can be used to compare two animated
+images (each can be GIF or WebP).
+
+Usage:
+
+```shell
+anim_diff <image1> <image2> [options]
+```
+
+Options:
+
+```
+-dump_frames <folder> dump decoded frames in PAM format
+-min_psnr <float> ... minimum per-frame PSNR
+-raw_comparison ..... if this flag is not used, RGB is
+                      premultiplied before comparison
+-max_diff <int> ..... maximum allowed difference per channel
+                      between corresponding pixels in subsequent
+                      frames
+-h .................. this help
+-version ............ print version number and exit
+```
+
+### Building
+
+With the libgif development files installed, anim_diff can be built using
+makefile.unix:
+
+```shell
+$ make -f makefile.unix examples/anim_diff
+```
+
+or using autoconf:
+
+```shell
+$ ./configure --enable-everything
+$ make
+```
+
+## WebP Mux tool
+
+The examples/ directory contains a tool (webpmux) for manipulating WebP files.
+The webpmux tool can be used to create an extended format WebP file and also to
+extract or strip relevant data from such a file.
+
+A list of options is available using the -help command line flag:
+
+```shell
+> webpmux -help
+Usage: webpmux -get GET_OPTIONS INPUT -o OUTPUT
+       webpmux -set SET_OPTIONS INPUT -o OUTPUT
+       webpmux -duration DURATION_OPTIONS [-duration ...]
+               INPUT -o OUTPUT
+       webpmux -strip STRIP_OPTIONS INPUT -o OUTPUT
+       webpmux -frame FRAME_OPTIONS [-frame...] [-loop LOOP_COUNT]
+               [-bgcolor BACKGROUND_COLOR] -o OUTPUT
+       webpmux -info INPUT
+       webpmux [-h|-help]
+       webpmux -version
+       webpmux argument_file_name
+
+GET_OPTIONS:
+ Extract relevant data:
+   icc       get ICC profile
+   exif      get EXIF metadata
+   xmp       get XMP metadata
+   frame n   get nth frame
+
+SET_OPTIONS:
+ Set color profile/metadata/parameters:
+   loop LOOP_COUNT            set the loop count
+   bgcolor BACKGROUND_COLOR   set the animation background color
+   icc  file.icc              set ICC profile
+   exif file.exif             set EXIF metadata
+   xmp  file.xmp              set XMP metadata
+   where:    'file.icc' contains the ICC profile to be set,
+             'file.exif' contains the EXIF metadata to be set
+             'file.xmp' contains the XMP metadata to be set
+
+DURATION_OPTIONS:
+ Set duration of selected frames:
+   duration            set duration for all frames
+   duration,frame      set duration of a particular frame
+   duration,start,end  set duration of frames in the
+                        interval [start,end])
+   where: 'duration' is the duration in milliseconds
+          'start' is the start frame index
+          'end' is the inclusive end frame index
+           The special 'end' value '0' means: last frame.
+
+STRIP_OPTIONS:
+ Strip color profile/metadata:
+   icc       strip ICC profile
+   exif      strip EXIF metadata
+   xmp       strip XMP metadata
+
+FRAME_OPTIONS(i):
+ Create animation:
+   file_i +di[+xi+yi[+mi[bi]]]
+   where:    'file_i' is the i'th animation frame (WebP format),
+             'di' is the pause duration before next frame,
+             'xi','yi' specify the image offset for this frame,
+             'mi' is the dispose method for this frame (0 or 1),
+             'bi' is the blending method for this frame (+b or -b)
+
+LOOP_COUNT:
+ Number of times to repeat the animation.
+ Valid range is 0 to 65535 [Default: 0 (infinite)].
+
+BACKGROUND_COLOR:
+ Background color of the canvas.
+  A,R,G,B
+  where:    'A', 'R', 'G' and 'B' are integers in the range 0 to 255 specifying
+            the Alpha, Red, Green and Blue component values respectively
+            [Default: 255,255,255,255]
+
+INPUT & OUTPUT are in WebP format.
+
+Note: The nature of EXIF, XMP and ICC data is not checked and is assumed to be
+valid.
+
+Note: if a single file name is passed as the argument, the arguments will be
+tokenized from this file. The file name must not start with the character '-'.
+```

doc/webp-container-spec.txt

@@ -0,0 +1,870 @@
+<!--
+
+Although you may be viewing an alternate representation, this document
+is sourced in Markdown, a light-duty markup scheme, and is optimized for
+the [kramdown](https://kramdown.gettalong.org/) transformer.
+
+See the accompanying specs_generation.md. External link targets are referenced
+at the end of this file.
+
+-->
+
+
+WebP Container Specification
+============================
+
+* TOC placeholder
+{:toc}
+
+
+Introduction
+------------
+
+WebP is an image format that uses either (i) the VP8 key frame encoding to
+compress image data in a lossy way or (ii) the WebP lossless encoding. These
+encoding schemes should make it more efficient than older formats, such as JPEG,
+GIF, and PNG. It is optimized for fast image transfer over the network (for
+example, for websites). The WebP format has feature parity (color profile,
+metadata, animation, etc.) with other formats as well. This document describes
+the structure of a WebP file.
+
+The WebP container (that is, the RIFF container for WebP) allows feature support
+over and above the basic use case of WebP (that is, a file containing a single
+image encoded as a VP8 key frame). The WebP container provides additional
+support for the following:
+
+  * Lossless Compression: An image can be losslessly compressed, using the
+    WebP Lossless Format.
+
+  * Metadata: An image may have metadata stored in Exchangeable Image File
+    Format (Exif) or Extensible Metadata Platform (XMP) format.
+
+  * Transparency: An image may have transparency, that is, an alpha channel.
+
+  * Color Profile: An image may have an embedded ICC profile as described
+    by the [International Color Consortium][iccspec].
+
+  * Animation: An image may have multiple frames with pauses between them,
+    making it an animation.
+
+Terminology & Basics
+--------------------
+
+The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
+"SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this
+document are to be interpreted as described in BCP 14 [RFC 2119][] [RFC 8174][]
+when, and only when, they appear in all capitals, as shown here.
+
+A WebP file contains either a still image (that is, an encoded matrix of pixels)
+or an [animation](#animation). Optionally, it can also contain transparency
+information, a color profile and metadata. We refer to the matrix of pixels as
+the _canvas_ of the image.
+
+Bit numbering in chunk diagrams starts at `0` for the most significant bit
+('MSB 0'), as described in [RFC 1166][].
+
+Below are additional terms used throughout this document:
+
+_Reader/Writer_
+
+: Code that reads WebP files is referred to as a _reader_, while code that
+  writes them is referred to as a _writer_.
+
+_uint16_
+
+: A 16-bit, little-endian, unsigned integer.
+
+_uint24_
+
+: A 24-bit, little-endian, unsigned integer.
+
+_uint32_
+
+: A 32-bit, little-endian, unsigned integer.
+
+_FourCC_
+
+: A four-character code (FourCC) is a _uint32_ created by concatenating four
+  ASCII characters in little-endian order. This means 'aaaa' (0x61616161) and
+ 'AAAA' (0x41414141) are treated as different _FourCCs_.
+
+_1-based_
+
+: An unsigned integer field storing values offset by `-1`, for example, such a
+  field would store value _25_ as _24_.
+
+_ChunkHeader('ABCD')_
+
+: Used to describe the _FourCC_ and _Chunk Size_ header of individual chunks,
+  where 'ABCD' is the FourCC for the chunk. This element's size is 8 bytes.
+
+
+RIFF File Format
+----------------
+
+The WebP file format is based on the RIFF (Resource Interchange File Format)
+document format.
+
+The basic element of a RIFF file is a _chunk_. It consists of:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                         Chunk FourCC                          |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                          Chunk Size                           |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                         Chunk Payload                         :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Chunk FourCC: 32 bits
+
+: ASCII four-character code used for chunk identification.
+
+Chunk Size: 32 bits (_uint32_)
+
+: The size of the chunk in bytes, not including this field, the chunk
+  identifier, or padding.
+
+Chunk Payload: _Chunk Size_ bytes
+
+: The data payload. If _Chunk Size_ is odd, a single padding byte -- which MUST
+  be `0` to conform with RIFF -- is added.
+
+**Note:** RIFF has a convention that all-uppercase chunk FourCCs are standard
+chunks that apply to any RIFF file format, while FourCCs specific to a file
+format are all lowercase. WebP does not follow this convention.
+
+
+WebP File Header
+----------------
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |      'R'      |      'I'      |      'F'      |      'F'      |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                           File Size                           |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |      'W'      |      'E'      |      'B'      |      'P'      |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+'RIFF': 32 bits
+
+: The ASCII characters 'R', 'I', 'F', 'F'.
+
+File Size: 32 bits (_uint32_)
+
+: The size of the file in bytes, starting at offset 8. The maximum value of
+  this field is 2^32 minus 10 bytes and thus the size of the whole file is at
+  most 4 GiB minus 2 bytes.
+
+'WEBP': 32 bits
+
+: The ASCII characters 'W', 'E', 'B', 'P'.
+
+A WebP file MUST begin with a RIFF header with the FourCC 'WEBP'. The file size
+in the header is the total size of the chunks that follow plus `4` bytes for
+the 'WEBP' FourCC. The file SHOULD NOT contain any data after the data
+specified by _File Size_. Readers MAY parse such files, ignoring the trailing
+data. As the size of any chunk is even, the size given by the RIFF header is
+also even. The contents of individual chunks are described in the following
+sections.
+
+
+Simple File Format (Lossy)
+--------------------------
+
+This layout SHOULD be used if the image requires _lossy_ encoding and does not
+require transparency or other advanced features provided by the extended format.
+Files with this layout are smaller and supported by older software.
+
+Simple WebP (lossy) file format:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                                                               |
+    |                    WebP file header (12 bytes)                |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                        'VP8 ' Chunk                           :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+'VP8 ' Chunk:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('VP8 ')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                           VP8 data                            :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+VP8 data: _Chunk Size_ bytes
+
+: VP8 bitstream data.
+
+Note that the fourth character in the 'VP8 ' FourCC is an ASCII space (0x20).
+
+The VP8 bitstream format specification is described in [VP8 Data Format and
+Decoding Guide][rfc 6386]. Note that the VP8 frame header contains the VP8 frame
+width and height. That is assumed to be the width and height of the canvas.
+
+The VP8 specification describes how to decode the image into Y'CbCr format. To
+convert to RGB, [Recommendation BT.601][rec601] SHOULD be used. Applications MAY
+use another conversion method, but visual results may differ among decoders.
+
+
+Simple File Format (Lossless)
+-----------------------------
+
+**Note:** Older readers may not support files using the lossless format.
+
+This layout SHOULD be used if the image requires _lossless_ encoding (with an
+optional transparency channel) and does not require advanced features provided
+by the extended format.
+
+Simple WebP (lossless) file format:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                                                               |
+    |                    WebP file header (12 bytes)                |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                         'VP8L' Chunk                          :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+'VP8L' Chunk:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('VP8L')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                           VP8L data                           :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+VP8L data: _Chunk Size_ bytes
+
+: VP8L bitstream data.
+
+The current specification of the VP8L bitstream can be found at
+[WebP Lossless Bitstream Format][webpllspec]. Note that the VP8L header
+contains the VP8L image width and height. That is assumed to be the width
+and height of the canvas.
+
+
+Extended File Format
+--------------------
+
+**Note:** Older readers may not support files using the extended format.
+
+An extended format file consists of:
+
+  * A 'VP8X' Chunk with information about features used in the file.
+
+  * An optional 'ICCP' Chunk with a color profile.
+
+  * An optional 'ANIM' Chunk with animation control data.
+
+  * Image data.
+
+  * An optional 'EXIF' Chunk with Exif metadata.
+
+  * An optional 'XMP ' Chunk with XMP metadata.
+
+  * An optional list of [unknown chunks](#unknown-chunks).
+
+For a _still image_, the _image data_ consists of a single frame, which is made
+up of:
+
+  * An optional [alpha subchunk](#alpha).
+
+  * A [bitstream subchunk](#bitstream-vp8vp8l).
+
+For an _animated image_, the _image data_ consists of multiple frames. More
+details about frames can be found in the [Animation](#animation) section.
+
+All chunks SHOULD be placed in the same order as listed above. If a chunk
+appears in the wrong place, the file is invalid, but readers MAY parse the
+file, ignoring the chunks that are out of order.
+
+**Rationale:** Setting the order of chunks should allow quicker file
+parsing. For example, if an 'ALPH' Chunk does not appear in its required
+position, a decoder can choose to stop searching for it. The rule of
+ignoring late chunks should make programs that need to do a full search
+give the same results as the ones stopping early.
+
+Extended WebP file header:
+{:#extended_header}
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                                                               |
+    |                   WebP file header (12 bytes)                 |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('VP8X')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |Rsv|I|L|E|X|A|R|                   Reserved                    |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |          Canvas Width Minus One               |             ...
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    ...  Canvas Height Minus One    |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Reserved (Rsv): 2 bits
+
+: MUST be `0`. Readers MUST ignore this field.
+
+ICC profile (I): 1 bit
+
+: Set if the file contains an 'ICCP' Chunk.
+
+Alpha (L): 1 bit
+
+: Set if any of the frames of the image contain transparency information
+  ("alpha").
+
+Exif metadata (E): 1 bit
+
+: Set if the file contains Exif metadata.
+
+XMP metadata (X): 1 bit
+
+: Set if the file contains XMP metadata.
+
+Animation (A): 1 bit
+
+: Set if this is an animated image. Data in 'ANIM' and 'ANMF' Chunks should be
+  used to control the animation.
+
+Reserved (R): 1 bit
+
+: MUST be `0`. Readers MUST ignore this field.
+
+Reserved: 24 bits
+
+: MUST be `0`. Readers MUST ignore this field.
+
+Canvas Width Minus One: 24 bits
+
+: _1-based_ width of the canvas in pixels.
+  The actual canvas width is `1 + Canvas Width Minus One`.
+
+Canvas Height Minus One: 24 bits
+
+: _1-based_ height of the canvas in pixels.
+  The actual canvas height is `1 + Canvas Height Minus One`.
+
+The product of _Canvas Width_ and _Canvas Height_ MUST be at most `2^32 - 1`.
+
+Future specifications may add more fields. Unknown fields MUST be ignored.
+
+### Chunks
+
+#### Animation
+
+An animation is controlled by 'ANIM' and 'ANMF' Chunks.
+
+'ANIM' Chunk:
+{:#anim_chunk}
+
+For an animated image, this chunk contains the _global parameters_ of the
+animation.
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('ANIM')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                       Background Color                        |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |          Loop Count           |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Background Color: 32 bits (_uint32_)
+
+: The default background color of the canvas in \[Blue, Green, Red, Alpha\]
+  byte order. This color MAY be used to fill the unused space on the canvas
+  around the frames, as well as the transparent pixels of the first frame.
+  The background color is also used when the Disposal method is `1`.
+
+**Note**:
+
+  * The background color MAY contain a non-opaque alpha value, even if the
+    _Alpha_ flag in the ['VP8X' Chunk](#extended_header) is unset.
+
+  * Viewer applications SHOULD treat the background color value as a hint and
+    are not required to use it.
+
+  * The canvas is cleared at the start of each loop. The background color MAY be
+    used to achieve this.
+
+Loop Count: 16 bits (_uint16_)
+
+: The number of times to loop the animation. If it is `0`, this means
+  infinitely.
+
+This chunk MUST appear if the _Animation_ flag in the 'VP8X' Chunk is set.
+If the _Animation_ flag is not set and this chunk is present, it MUST be
+ignored.
+
+'ANMF' Chunk:
+
+For animated images, this chunk contains information about a _single_ frame.
+If the _Animation flag_ is not set, then this chunk SHOULD NOT be present.
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('ANMF')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                        Frame X                |             ...
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    ...          Frame Y            |   Frame Width Minus One     ...
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    ...             |           Frame Height Minus One              |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                 Frame Duration                |  Reserved |B|D|
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                         Frame Data                            :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Frame X: 24 bits (_uint24_)
+
+: The X coordinate of the upper left corner of the frame is `Frame X * 2`.
+
+Frame Y: 24 bits (_uint24_)
+
+: The Y coordinate of the upper left corner of the frame is `Frame Y * 2`.
+
+Frame Width Minus One: 24 bits (_uint24_)
+
+: The _1-based_ width of the frame.
+  The frame width is `1 + Frame Width Minus One`.
+
+Frame Height Minus One: 24 bits (_uint24_)
+
+: The _1-based_ height of the frame.
+  The frame height is `1 + Frame Height Minus One`.
+
+Frame Duration: 24 bits (_uint24_)
+
+: The time to wait before displaying the next frame, in 1-millisecond units.
+  Note that the interpretation of the Frame Duration of 0 (and often <= 10) is
+  defined by the implementation. Many tools and browsers assign a minimum
+  duration similar to GIF.
+
+Reserved: 6 bits
+
+: MUST be `0`. Readers MUST ignore this field.
+
+Blending method (B): 1 bit
+
+: Indicates how transparent pixels of _the current frame_ are to be blended
+  with corresponding pixels of the previous canvas:
+
+    * `0`: Use alpha-blending. After disposing of the previous frame, render the
+      current frame on the canvas using [alpha-blending](#alpha-blending). If
+      the current frame does not have an alpha channel, assume the alpha value
+      is 255, effectively replacing the rectangle.
+
+    * `1`: Do not blend. After disposing of the previous frame, render the
+      current frame on the canvas by overwriting the rectangle covered by the
+      current frame.
+
+Disposal method (D): 1 bit
+
+: Indicates how _the current frame_ is to be treated after it has been
+  displayed (before rendering the next frame) on the canvas:
+
+    * `0`: Do not dispose. Leave the canvas as is.
+
+    * `1`: Dispose to the background color. Fill the _rectangle_ on the canvas
+      covered by the _current frame_ with the background color specified in the
+      ['ANIM' Chunk](#anim_chunk).
+
+**Notes**:
+
+  * The frame disposal only applies to the _frame rectangle_, that is, the
+    rectangle defined by _Frame X_, _Frame Y_, _frame width_, and _frame
+    height_. It may or may not cover the whole canvas.
+
+{:#alpha-blending}
+  * Alpha-blending:
+
+    Given that each of the R, G, B, and A channels is 8 bits, and the RGB
+    channels are _not premultiplied_ by alpha, the formula for blending
+    'dst' onto 'src' is:
+
+~~~~~
+    blend.A = src.A + dst.A * (1 - src.A / 255)
+    if blend.A = 0 then
+      blend.RGB = 0
+    else
+      blend.RGB =
+          (src.RGB * src.A +
+           dst.RGB * dst.A * (1 - src.A / 255)) / blend.A
+~~~~~
+
+  * Alpha-blending SHOULD be done in linear color space, by taking into account
+    the [color profile](#color-profile) of the image. If the color profile is
+    not present, standard RGB (sRGB) is to be assumed. (Note that sRGB also
+    needs to be linearized due to a gamma of ~2.2.)
+
+Frame Data: _Chunk Size_ - `16` bytes
+
+: Consists of:
+
+  * An optional [alpha subchunk](#alpha) for the frame.
+
+  * A [bitstream subchunk](#bitstream-vp8vp8l) for the frame.
+
+  * An optional list of [unknown chunks](#unknown-chunks).
+
+**Note**: The 'ANMF' payload, _Frame Data_ above, consists of individual
+_padded_ chunks, as described by the [RIFF file format](#riff-file-format).
+
+#### Alpha
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('ALPH')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |Rsv| P | F | C |     Alpha Bitstream...                        |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Reserved (Rsv): 2 bits
+
+: MUST be `0`. Readers MUST ignore this field.
+
+Preprocessing (P): 2 bits
+
+: These _informative_ bits are used to signal the preprocessing that has
+  been performed during compression. The decoder can use this information to
+  for example, dither the values or smooth the gradients prior to display.
+
+    * `0`: No preprocessing.
+    * `1`: Level reduction.
+
+Decoders are not required to use this information in any specified way.
+
+Filtering method (F): 2 bits
+
+: The filtering methods used are described as follows:
+
+    * `0`: None.
+    * `1`: Horizontal filter.
+    * `2`: Vertical filter.
+    * `3`: Gradient filter.
+
+For each pixel, filtering is performed using the following calculations.
+Assume the alpha values surrounding the current `X` position are labeled as:
+
+     C | B |
+    ---+---+
+     A | X |
+
+We seek to compute the alpha value at position `X`. First, a prediction is
+made depending on the filtering method:
+
+  * Method `0`: predictor = 0
+  * Method `1`: predictor = A
+  * Method `2`: predictor = B
+  * Method `3`: predictor = clip(A + B - C)
+
+where `clip(v)` is equal to:
+
+  * 0    if v < 0,
+  * 255  if v > 255, or
+  * v    otherwise
+
+The final value is derived by adding the decompressed value `X` to the
+predictor and using modulo-256 arithmetic to wrap the \[256..511\] range
+into the \[0..255\] one:
+
+`alpha = (predictor + X) % 256`
+
+There are special cases for the left-most and top-most pixel positions. For
+example, the top-left value at location (0, 0) uses 0 as the predictor value.
+Otherwise:
+
+  * For horizontal or gradient filtering methods, the left-most pixels at
+    location (0, y) are predicted using the location (0, y-1) just above.
+  * For vertical or gradient filtering methods, the top-most pixels at
+    location (x, 0) are predicted using the location (x-1, 0) on the left.
+
+Compression method (C): 2 bits
+
+: The compression method used:
+
+    * `0`: No compression.
+    * `1`: Compressed using the WebP lossless format.
+
+Alpha bitstream: _Chunk Size_ - `1` bytes
+
+: Encoded alpha bitstream.
+
+This optional chunk contains encoded alpha data for this frame. A frame
+containing a 'VP8L' Chunk SHOULD NOT contain this chunk.
+
+**Rationale**: The transparency information is already part of the 'VP8L'
+Chunk.
+
+The alpha channel data is stored as uncompressed raw data (when the
+compression method is '0') or compressed using the lossless format
+(when the compression method is '1').
+
+  * Raw data: This consists of a byte sequence of length = width * height,
+    containing all the 8-bit transparency values in scan order.
+
+  * Lossless format compression: The byte sequence is a compressed
+    image-stream (as described in ["WebP Lossless Bitstream Format"]
+    [webpllspec]) of implicit dimensions width x height. That is, this
+    image-stream does NOT contain any headers describing the image dimensions.
+
+    **Rationale**: The dimensions are already known from other sources,
+    so storing them again would be redundant and prone to error.
+
+    Once the image-stream is decoded into Alpha, Red, Green, Blue (ARGB) color
+    values, following the process described in the lossless format
+    specification, the transparency information must be extracted from the
+    *green* channel of the ARGB quadruplet.
+
+    **Rationale**: The green channel is allowed extra transformation
+    steps in the specification -- unlike the other channels -- that can
+    improve compression.
+
+#### Bitstream (VP8/VP8L)
+
+This chunk contains compressed bitstream data for a single frame.
+
+A bitstream chunk may be either (i) a 'VP8 ' Chunk, using 'VP8 ' (note the
+significant fourth-character space) as its FourCC, _or_ (ii) a 'VP8L' Chunk,
+using 'VP8L' as its FourCC.
+
+The formats of 'VP8 ' and 'VP8L' Chunks are as described in sections
+[Simple File Format (Lossy)](#simple-file-format-lossy)
+and [Simple File Format (Lossless)](#simple-file-format-lossless), respectively.
+
+#### Color Profile
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('ICCP')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                       Color Profile                           :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Color Profile: _Chunk Size_ bytes
+
+: ICC profile.
+
+This chunk MUST appear before the image data.
+
+There SHOULD be at most one such chunk. If there are more such chunks, readers
+MAY ignore all except the first one.
+See the [ICC Specification][iccspec] for details.
+
+If this chunk is not present, sRGB SHOULD be assumed.
+
+#### Metadata
+
+Metadata can be stored in 'EXIF' or 'XMP ' Chunks.
+
+There SHOULD be at most one chunk of each type ('EXIF' and 'XMP '). If there
+are more such chunks, readers MAY ignore all except the first one.
+
+The chunks are defined as follows:
+
+'EXIF' Chunk:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('EXIF')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                        Exif Metadata                          :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Exif Metadata: _Chunk Size_ bytes
+
+: Image metadata in Exif format.
+
+'XMP ' Chunk:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('XMP ')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                        XMP Metadata                           :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+XMP Metadata: _Chunk Size_ bytes
+
+: Image metadata in XMP format.
+
+Note that the fourth character in the 'XMP ' FourCC is an ASCII space (0x20).
+
+Additional guidance about handling metadata can be found in the
+Metadata Working Group's ["Guidelines for Handling Metadata"][metadata].
+
+#### Unknown Chunks
+
+A RIFF chunk (described in the [RIFF File Format](#riff-file-format) section)
+whose FourCC is different from any of the chunks described in this document, is
+considered an _unknown chunk_.
+
+**Rationale**: Allowing unknown chunks gives a provision for future extension
+of the format and also allows storage of any application-specific data.
+
+A file MAY contain unknown chunks:
+
+  * at the end of the file, as described in [Extended WebP file
+    header](#extended_header) section, or
+  * at the end of 'ANMF' Chunks, as described in the
+    [Animation](#animation) section.
+
+Readers SHOULD ignore these chunks. Writers SHOULD preserve them in their
+original order (unless they specifically intend to modify these chunks).
+
+### Canvas Assembly from Frames
+
+Here we provide an overview of how a reader MUST assemble a canvas in the case
+of an animated image.
+
+The process begins with creating a canvas using the dimensions given in the
+'VP8X' Chunk, `Canvas Width Minus One + 1` pixels wide by `Canvas Height Minus
+One + 1` pixels high. The `Loop Count` field from the 'ANIM' Chunk controls how
+many times the animation process is repeated. This is `Loop Count - 1` for
+nonzero `Loop Count` values or infinite if the `Loop Count` is zero.
+
+At the beginning of each loop iteration, the canvas is filled using the
+background color from the 'ANIM' Chunk or an application-defined color.
+
+'ANMF' Chunks contain individual frames given in display order. Before rendering
+each frame, the previous frame's `Disposal method` is applied.
+
+The rendering of the decoded frame begins at the Cartesian coordinates (`2 *
+Frame X`, `2 * Frame Y`), using the top-left corner of the canvas as the origin.
+`Frame Width Minus One + 1` pixels wide by `Frame Height Minus One + 1` pixels
+high are rendered onto the canvas using the `Blending method`.
+
+The canvas is displayed for `Frame Duration` milliseconds. This continues until
+all frames given by 'ANMF' Chunks have been displayed. A new loop iteration is
+then begun, or the canvas is left in its final state if all iterations have been
+completed.
+
+The following pseudocode illustrates the rendering process. The notation
+_VP8X.field_ means the field in the 'VP8X' Chunk with the same description.
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+assert VP8X.flags.hasAnimation
+canvas ← new image of size VP8X.canvasWidth x VP8X.canvasHeight with
+         background color ANIM.background_color.
+loop_count ← ANIM.loopCount
+dispose_method ← Dispose to background color
+if loop_count == 0:
+  loop_count = ∞
+frame_params ← nil
+assert next chunk in image_data is ANMF
+for loop = 0..loop_count - 1
+  clear canvas to ANIM.background_color or application-defined color
+  until eof or non-ANMF chunk
+    frame_params.frameX = Frame X
+    frame_params.frameY = Frame Y
+    frame_params.frameWidth = Frame Width Minus One + 1
+    frame_params.frameHeight = Frame Height Minus One + 1
+    frame_params.frameDuration = Frame Duration
+    frame_right = frame_params.frameX + frame_params.frameWidth
+    frame_bottom = frame_params.frameY + frame_params.frameHeight
+    assert VP8X.canvasWidth >= frame_right
+    assert VP8X.canvasHeight >= frame_bottom
+    for subchunk in 'Frame Data':
+      if subchunk.tag == "ALPH":
+        assert alpha subchunks not found in 'Frame Data' earlier
+        frame_params.alpha = alpha_data
+      else if subchunk.tag == "VP8 " OR subchunk.tag == "VP8L":
+        assert bitstream subchunks not found in 'Frame Data' earlier
+        frame_params.bitstream = bitstream_data
+    render frame with frame_params.alpha and frame_params.bitstream
+      on canvas with top-left corner at (frame_params.frameX,
+      frame_params.frameY), using Blending method
+      frame_params.blendingMethod.
+    canvas contains the decoded image.
+    Show the contents of the canvas for
+    frame_params.frameDuration * 1 ms.
+    dispose_method = frame_params.disposeMethod
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+
+Example File Layouts
+--------------------
+
+A lossy-encoded image with alpha may look as follows:
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+RIFF/WEBP
++- VP8X (descriptions of features used)
++- ALPH (alpha bitstream)
++- VP8 (bitstream)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A lossless-encoded image may look as follows:
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+RIFF/WEBP
++- VP8X (descriptions of features used)
++- XYZW (unknown chunk)
++- VP8L (lossless bitstream)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A lossless image with an ICC profile and XMP metadata may
+look as follows:
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+RIFF/WEBP
++- VP8X (descriptions of features used)
++- ICCP (color profile)
++- VP8L (lossless bitstream)
++- XMP  (metadata)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+An animated image with Exif metadata may look as follows:
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+RIFF/WEBP
++- VP8X (descriptions of features used)
++- ANIM (global animation parameters)
++- ANMF (frame1 parameters + data)
++- ANMF (frame2 parameters + data)
++- ANMF (frame3 parameters + data)
++- ANMF (frame4 parameters + data)
++- EXIF (metadata)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+[webpllspec]: https://chromium.googlesource.com/webm/libwebp/+/HEAD/doc/webp-lossless-bitstream-spec.txt
+[iccspec]: https://www.color.org/icc_specs2.xalter
+[metadata]: https://web.archive.org/web/20180919181934/http://www.metadataworkinggroup.org/pdf/mwg_guidance.pdf
+[rec601]: https://www.itu.int/rec/R-REC-BT.601
+[rfc 1166]: https://datatracker.ietf.org/doc/html/rfc1166
+[rfc 2119]: https://datatracker.ietf.org/doc/html/rfc2119
+[rfc 6386]: https://datatracker.ietf.org/doc/html/rfc6386
+[rfc 8174]: https://datatracker.ietf.org/doc/html/rfc8174

examples/Android.mk

@@ -0,0 +1,96 @@
+# Ignore this file during non-NDK builds.
+ifdef NDK_ROOT
+LOCAL_PATH := $(call my-dir)
+
+################################################################################
+# libexample_util
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    example_util.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
+
+LOCAL_MODULE := example_util
+
+include $(BUILD_STATIC_LIBRARY)
+
+################################################################################
+# cwebp
+
+include $(CLEAR_VARS)
+
+# Note: to enable jpeg/png encoding the sources from AOSP can be used with
+# minor modification to their Android.mk files.
+LOCAL_SRC_FILES := \
+    cwebp.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_STATIC_LIBRARIES := example_util imageio_util imagedec webpdemux webp
+
+LOCAL_MODULE := cwebp
+
+include $(BUILD_EXECUTABLE)
+
+################################################################################
+# dwebp
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    dwebp.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_STATIC_LIBRARIES := example_util imagedec imageenc webpdemux webp
+LOCAL_MODULE := dwebp
+
+include $(BUILD_EXECUTABLE)
+
+################################################################################
+# webpmux
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    webpmux.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_STATIC_LIBRARIES := example_util imageio_util webpmux webp
+
+LOCAL_MODULE := webpmux_example
+
+include $(BUILD_EXECUTABLE)
+
+################################################################################
+# img2webp
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    img2webp.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_STATIC_LIBRARIES := example_util imageio_util imagedec webpmux webpdemux \
+                          webp
+
+LOCAL_MODULE := img2webp_example
+
+include $(BUILD_EXECUTABLE)
+
+################################################################################
+# webpinfo
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    webpinfo.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_STATIC_LIBRARIES := example_util imageio_util webp
+
+LOCAL_MODULE := webpinfo_example
+
+include $(BUILD_EXECUTABLE)
+endif  # NDK_ROOT

examples/Makefile.am

@@ -0,0 +1,119 @@
+AM_CPPFLAGS += -I$(top_builddir)/src -I$(top_srcdir)/src
+
+bin_PROGRAMS =
+if BUILD_DEMUX
+  bin_PROGRAMS += dwebp cwebp
+endif
+if BUILD_ANIMDIFF
+  noinst_PROGRAMS = anim_diff anim_dump
+endif
+if BUILD_GIF2WEBP
+  bin_PROGRAMS += gif2webp
+endif
+if BUILD_IMG2WEBP
+  bin_PROGRAMS += img2webp
+endif
+if BUILD_MUX
+  bin_PROGRAMS += webpmux
+endif
+if BUILD_VWEBP
+  bin_PROGRAMS += vwebp
+endif
+if BUILD_WEBPINFO
+  bin_PROGRAMS += webpinfo
+endif
+
+noinst_LTLIBRARIES = libexample_util.la
+
+libexample_util_la_SOURCES = example_util.c example_util.h
+libexample_util_la_LIBADD = ../src/libwebp.la
+
+anim_diff_SOURCES = anim_diff.c anim_util.c anim_util.h gifdec.c gifdec.h
+anim_diff_CPPFLAGS = $(AM_CPPFLAGS) $(GIF_INCLUDES)
+anim_diff_LDADD  =
+anim_diff_LDADD += ../src/demux/libwebpdemux.la
+anim_diff_LDADD += libexample_util.la
+anim_diff_LDADD += ../imageio/libimageio_util.la
+anim_diff_LDADD += $(GIF_LIBS) -lm
+
+anim_dump_SOURCES = anim_dump.c anim_util.c anim_util.h gifdec.c gifdec.h
+anim_dump_CPPFLAGS = $(AM_CPPFLAGS) $(PNG_INCLUDES)
+anim_dump_CPPFLAGS += $(GIF_INCLUDES)
+anim_dump_LDADD  =
+anim_dump_LDADD += ../src/demux/libwebpdemux.la
+anim_dump_LDADD += libexample_util.la
+anim_dump_LDADD += ../imageio/libimageio_util.la
+anim_dump_LDADD += ../imageio/libimageenc.la
+anim_dump_LDADD += $(PNG_LIBS) $(GIF_LIBS) $(TIFF_LIBS) -lm
+
+cwebp_SOURCES  = cwebp.c stopwatch.h
+cwebp_CPPFLAGS  = $(AM_CPPFLAGS) -I$(top_srcdir)
+cwebp_LDADD  =
+cwebp_LDADD += libexample_util.la
+cwebp_LDADD += ../imageio/libimageio_util.la
+cwebp_LDADD += ../imageio/libimagedec.la
+cwebp_LDADD += ../src/libwebp.la
+cwebp_LDADD += $(JPEG_LIBS) $(PNG_LIBS) $(TIFF_LIBS)
+
+dwebp_SOURCES = dwebp.c stopwatch.h
+dwebp_CPPFLAGS  = $(AM_CPPFLAGS)
+dwebp_CPPFLAGS += $(JPEG_INCLUDES) $(PNG_INCLUDES)
+dwebp_LDADD  =
+dwebp_LDADD += libexample_util.la
+dwebp_LDADD += ../imageio/libimagedec.la
+dwebp_LDADD += ../imageio/libimageenc.la
+dwebp_LDADD += ../imageio/libimageio_util.la
+dwebp_LDADD += ../src/libwebp.la
+dwebp_LDADD +=$(PNG_LIBS) $(JPEG_LIBS)
+
+gif2webp_SOURCES = gif2webp.c gifdec.c gifdec.h
+gif2webp_CPPFLAGS = $(AM_CPPFLAGS) $(GIF_INCLUDES)
+gif2webp_LDADD  =
+gif2webp_LDADD += libexample_util.la
+gif2webp_LDADD += ../imageio/libimageio_util.la
+gif2webp_LDADD += ../src/mux/libwebpmux.la
+gif2webp_LDADD += ../src/libwebp.la
+gif2webp_LDADD += $(GIF_LIBS)
+
+vwebp_SOURCES = vwebp.c
+vwebp_CPPFLAGS = $(AM_CPPFLAGS) $(GL_INCLUDES)
+vwebp_LDADD  =
+vwebp_LDADD += libexample_util.la
+vwebp_LDADD += ../imageio/libimageio_util.la
+vwebp_LDADD += ../src/demux/libwebpdemux.la
+vwebp_LDADD += $(GL_LIBS)
+
+webpmux_SOURCES = webpmux.c
+webpmux_CPPFLAGS = $(AM_CPPFLAGS)
+webpmux_LDADD  =
+webpmux_LDADD += libexample_util.la
+webpmux_LDADD += ../imageio/libimageio_util.la
+webpmux_LDADD += ../src/mux/libwebpmux.la
+webpmux_LDADD += ../src/libwebp.la
+
+img2webp_SOURCES = img2webp.c
+img2webp_CPPFLAGS = $(AM_CPPFLAGS) -I$(top_srcdir)
+img2webp_LDADD  =
+img2webp_LDADD += libexample_util.la
+img2webp_LDADD += ../imageio/libimageio_util.la
+img2webp_LDADD += ../imageio/libimagedec.la
+img2webp_LDADD += ../src/mux/libwebpmux.la
+img2webp_LDADD += ../src/libwebp.la
+img2webp_LDADD += $(PNG_LIBS) $(JPEG_LIBS) $(TIFF_LIBS)
+
+webpinfo_SOURCES = webpinfo.c
+webpinfo_CPPFLAGS = $(AM_CPPFLAGS)
+webpinfo_LDADD  =
+webpinfo_LDADD += libexample_util.la
+webpinfo_LDADD += ../imageio/libimageio_util.la
+webpinfo_LDADD += ../src/libwebp.la
+
+if BUILD_LIBWEBPDECODER
+  anim_diff_LDADD += ../src/libwebpdecoder.la
+  anim_dump_LDADD += ../src/libwebpdecoder.la
+  vwebp_LDADD += ../src/libwebpdecoder.la
+else
+  anim_diff_LDADD += ../src/libwebp.la
+  anim_dump_LDADD += ../src/libwebp.la
+  vwebp_LDADD += ../src/libwebp.la
+endif

examples/anim_diff.c

@@ -0,0 +1,317 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Checks if given pair of animated GIF/WebP images are identical:
+// That is: their reconstructed canvases match pixel-by-pixel and their other
+// animation properties (loop count etc) also match.
+//
+// example: anim_diff foo.gif bar.webp
+
+#include <assert.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>  // for 'strtod'.
+#include <string.h>  // for 'strcmp'.
+
+#include "./anim_util.h"
+#include "./example_util.h"
+#include "./unicode.h"
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf
+#endif
+
+// Returns true if 'a + b' will overflow.
+static int AdditionWillOverflow(int a, int b) {
+  return (b > 0) && (a > INT_MAX - b);
+}
+
+static int FramesAreEqual(const uint8_t* const rgba1,
+                          const uint8_t* const rgba2, int width, int height) {
+  const int stride = width * 4;  // Always true for 'DecodedFrame.rgba'.
+  return !memcmp(rgba1, rgba2, stride * height);
+}
+
+static WEBP_INLINE int PixelsAreSimilar(uint32_t src, uint32_t dst,
+                                        int max_allowed_diff) {
+  const int src_a = (src >> 24) & 0xff;
+  const int src_r = (src >> 16) & 0xff;
+  const int src_g = (src >> 8) & 0xff;
+  const int src_b = (src >> 0) & 0xff;
+  const int dst_a = (dst >> 24) & 0xff;
+  const int dst_r = (dst >> 16) & 0xff;
+  const int dst_g = (dst >> 8) & 0xff;
+  const int dst_b = (dst >> 0) & 0xff;
+
+  return (abs(src_r * src_a - dst_r * dst_a) <= (max_allowed_diff * 255)) &&
+         (abs(src_g * src_a - dst_g * dst_a) <= (max_allowed_diff * 255)) &&
+         (abs(src_b * src_a - dst_b * dst_a) <= (max_allowed_diff * 255)) &&
+         (abs(src_a - dst_a) <= max_allowed_diff);
+}
+
+static int FramesAreSimilar(const uint8_t* const rgba1,
+                            const uint8_t* const rgba2,
+                            int width, int height, int max_allowed_diff) {
+  int i, j;
+  assert(max_allowed_diff > 0);
+  for (j = 0; j < height; ++j) {
+    for (i = 0; i < width; ++i) {
+      const int stride = width * 4;
+      const size_t offset = j * stride + i;
+      if (!PixelsAreSimilar(rgba1[offset], rgba2[offset], max_allowed_diff)) {
+        return 0;
+      }
+    }
+  }
+  return 1;
+}
+
+// Minimize number of frames by combining successive frames that have at max
+// 'max_diff' difference per channel between corresponding pixels.
+static void MinimizeAnimationFrames(AnimatedImage* const img, int max_diff) {
+  uint32_t i;
+  for (i = 1; i < img->num_frames; ++i) {
+    DecodedFrame* const frame1 = &img->frames[i - 1];
+    DecodedFrame* const frame2 = &img->frames[i];
+    const uint8_t* const rgba1 = frame1->rgba;
+    const uint8_t* const rgba2 = frame2->rgba;
+    int should_merge_frames = 0;
+    // If merging frames will result in integer overflow for 'duration',
+    // skip merging.
+    if (AdditionWillOverflow(frame1->duration, frame2->duration)) continue;
+    if (max_diff > 0) {
+      should_merge_frames = FramesAreSimilar(rgba1, rgba2, img->canvas_width,
+                                             img->canvas_height, max_diff);
+    } else {
+      should_merge_frames =
+          FramesAreEqual(rgba1, rgba2, img->canvas_width, img->canvas_height);
+    }
+    if (should_merge_frames) {  // Merge 'i+1'th frame into 'i'th frame.
+      frame1->duration += frame2->duration;
+      if (i + 1 < img->num_frames) {
+        memmove(&img->frames[i], &img->frames[i + 1],
+                (img->num_frames - i - 1) * sizeof(*img->frames));
+      }
+      --img->num_frames;
+      --i;
+    }
+  }
+}
+
+static int CompareValues(uint32_t a, uint32_t b, const char* output_str) {
+  if (a != b) {
+    fprintf(stderr, "%s: %d vs %d\n", output_str, a, b);
+    return 0;
+  }
+  return 1;
+}
+
+static int CompareBackgroundColor(uint32_t bg1, uint32_t bg2, int premultiply) {
+  if (premultiply) {
+    const int alpha1 = (bg1 >> 24) & 0xff;
+    const int alpha2 = (bg2 >> 24) & 0xff;
+    if (alpha1 == 0 && alpha2 == 0) return 1;
+  }
+  if (bg1 != bg2) {
+    fprintf(stderr, "Background color mismatch: 0x%08x vs 0x%08x\n",
+            bg1, bg2);
+    return 0;
+  }
+  return 1;
+}
+
+// Note: As long as frame durations and reconstructed frames are identical, it
+// is OK for other aspects like offsets, dispose/blend method to vary.
+static int CompareAnimatedImagePair(const AnimatedImage* const img1,
+                                    const AnimatedImage* const img2,
+                                    int premultiply,
+                                    double min_psnr) {
+  int ok = 1;
+  const int is_multi_frame_image = (img1->num_frames > 1);
+  uint32_t i;
+
+  ok = CompareValues(img1->canvas_width, img2->canvas_width,
+                     "Canvas width mismatch") && ok;
+  ok = CompareValues(img1->canvas_height, img2->canvas_height,
+                     "Canvas height mismatch") && ok;
+  ok = CompareValues(img1->num_frames, img2->num_frames,
+                     "Frame count mismatch") && ok;
+  if (!ok) return 0;  // These are fatal failures, can't proceed.
+
+  if (is_multi_frame_image) {  // Checks relevant for multi-frame images only.
+    int max_loop_count_workaround = 0;
+    // Transcodes to webp increase the gif loop count by 1 for compatibility.
+    // When the gif has the maximum value the webp value will be off by one.
+    if ((img1->format == ANIM_GIF && img1->loop_count == 65536 &&
+         img2->format == ANIM_WEBP && img2->loop_count == 65535) ||
+        (img1->format == ANIM_WEBP && img1->loop_count == 65535 &&
+         img2->format == ANIM_GIF && img2->loop_count == 65536)) {
+      max_loop_count_workaround = 1;
+    }
+    ok = (max_loop_count_workaround ||
+          CompareValues(img1->loop_count, img2->loop_count,
+                        "Loop count mismatch")) && ok;
+    ok = CompareBackgroundColor(img1->bgcolor, img2->bgcolor,
+                                premultiply) && ok;
+  }
+
+  for (i = 0; i < img1->num_frames; ++i) {
+    // Pixel-by-pixel comparison.
+    const uint8_t* const rgba1 = img1->frames[i].rgba;
+    const uint8_t* const rgba2 = img2->frames[i].rgba;
+    int max_diff;
+    double psnr;
+    if (is_multi_frame_image) {  // Check relevant for multi-frame images only.
+      const char format[] = "Frame #%d, duration mismatch";
+      char tmp[sizeof(format) + 8];
+      ok = ok && (snprintf(tmp, sizeof(tmp), format, i) >= 0);
+      ok = ok && CompareValues(img1->frames[i].duration,
+                               img2->frames[i].duration, tmp);
+    }
+    GetDiffAndPSNR(rgba1, rgba2, img1->canvas_width, img1->canvas_height,
+                   premultiply, &max_diff, &psnr);
+    if (min_psnr > 0.) {
+      if (psnr < min_psnr) {
+        fprintf(stderr, "Frame #%d, psnr = %.2lf (min_psnr = %f)\n", i,
+                psnr, min_psnr);
+        ok = 0;
+      }
+    } else {
+      if (max_diff != 0) {
+        fprintf(stderr, "Frame #%d, max pixel diff: %d\n", i, max_diff);
+        ok = 0;
+      }
+    }
+  }
+  return ok;
+}
+
+static void Help(void) {
+  printf("Usage: anim_diff <image1> <image2> [options]\n");
+  printf("\nOptions:\n");
+  printf("  -dump_frames <folder> dump decoded frames in PAM format\n");
+  printf("  -min_psnr <float> ... minimum per-frame PSNR\n");
+  printf("  -raw_comparison ..... if this flag is not used, RGB is\n");
+  printf("                        premultiplied before comparison\n");
+  printf("  -max_diff <int> ..... maximum allowed difference per channel\n"
+         "                        between corresponding pixels in subsequent\n"
+         "                        frames\n");
+  printf("  -h .................. this help\n");
+  printf("  -version ............ print version number and exit\n");
+}
+
+int main(int argc, const char* argv[]) {
+  int return_code = -1;
+  int dump_frames = 0;
+  const char* dump_folder = NULL;
+  double min_psnr = 0.;
+  int got_input1 = 0;
+  int got_input2 = 0;
+  int premultiply = 1;
+  int max_diff = 0;
+  int i, c;
+  const char* files[2] = { NULL, NULL };
+  AnimatedImage images[2];
+
+  INIT_WARGV(argc, argv);
+
+  for (c = 1; c < argc; ++c) {
+    int parse_error = 0;
+    if (!strcmp(argv[c], "-dump_frames")) {
+      if (c < argc - 1) {
+        dump_frames = 1;
+        dump_folder = (const char*)GET_WARGV(argv, ++c);
+      } else {
+        parse_error = 1;
+      }
+    } else if (!strcmp(argv[c], "-min_psnr")) {
+      if (c < argc - 1) {
+        min_psnr = ExUtilGetFloat(argv[++c], &parse_error);
+      } else {
+        parse_error = 1;
+      }
+    } else if (!strcmp(argv[c], "-raw_comparison")) {
+      premultiply = 0;
+    } else if (!strcmp(argv[c], "-max_diff")) {
+      if (c < argc - 1) {
+        max_diff = ExUtilGetInt(argv[++c], 0, &parse_error);
+      } else {
+        parse_error = 1;
+      }
+    } else if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+      Help();
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-version")) {
+      int dec_version, demux_version;
+      GetAnimatedImageVersions(&dec_version, &demux_version);
+      printf("WebP Decoder version: %d.%d.%d\nWebP Demux version: %d.%d.%d\n",
+             (dec_version >> 16) & 0xff, (dec_version >> 8) & 0xff,
+             (dec_version >> 0) & 0xff,
+             (demux_version >> 16) & 0xff, (demux_version >> 8) & 0xff,
+             (demux_version >> 0) & 0xff);
+      FREE_WARGV_AND_RETURN(0);
+    } else {
+      if (!got_input1) {
+        files[0] = (const char*)GET_WARGV(argv, c);
+        got_input1 = 1;
+      } else if (!got_input2) {
+        files[1] = (const char*)GET_WARGV(argv, c);
+        got_input2 = 1;
+      } else {
+        parse_error = 1;
+      }
+    }
+    if (parse_error) {
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    }
+  }
+  if (argc < 3) {
+    Help();
+    FREE_WARGV_AND_RETURN(-1);
+  }
+
+
+  if (!got_input2) {
+    Help();
+    FREE_WARGV_AND_RETURN(-1);
+  }
+
+  if (dump_frames) {
+    WPRINTF("Dumping decoded frames in: %s\n", (const W_CHAR*)dump_folder);
+  }
+
+  memset(images, 0, sizeof(images));
+  for (i = 0; i < 2; ++i) {
+    WPRINTF("Decoding file: %s\n", (const W_CHAR*)files[i]);
+    if (!ReadAnimatedImage(files[i], &images[i], dump_frames, dump_folder)) {
+      WFPRINTF(stderr, "Error decoding file: %s\n Aborting.\n",
+               (const W_CHAR*)files[i]);
+      return_code = -2;
+      goto End;
+    } else {
+      MinimizeAnimationFrames(&images[i], max_diff);
+    }
+  }
+
+  if (!CompareAnimatedImagePair(&images[0], &images[1],
+                                premultiply, min_psnr)) {
+    WFPRINTF(stderr, "\nFiles %s and %s differ.\n", (const W_CHAR*)files[0],
+             (const W_CHAR*)files[1]);
+    return_code = -3;
+  } else {
+    WPRINTF("\nFiles %s and %s are identical.\n", (const W_CHAR*)files[0],
+            (const W_CHAR*)files[1]);
+    return_code = 0;
+  }
+ End:
+  ClearAnimatedImage(&images[0]);
+  ClearAnimatedImage(&images[1]);
+  FREE_WARGV_AND_RETURN(return_code);
+}

examples/anim_dump.c

@@ -0,0 +1,121 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Decodes an animated WebP file and dumps the decoded frames as PNG or TIFF.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include <stdio.h>
+#include <string.h>  // for 'strcmp'.
+
+#include "./anim_util.h"
+#include "webp/decode.h"
+#include "../imageio/image_enc.h"
+#include "./unicode.h"
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf
+#endif
+
+static void Help(void) {
+  printf("Usage: anim_dump [options] files...\n");
+  printf("\nOptions:\n");
+  printf("  -folder <string> .... dump folder (default: '.')\n");
+  printf("  -prefix <string> .... prefix for dumped frames "
+                                  "(default: 'dump_')\n");
+  printf("  -tiff ............... save frames as TIFF\n");
+  printf("  -pam ................ save frames as PAM\n");
+  printf("  -h .................. this help\n");
+  printf("  -version ............ print version number and exit\n");
+}
+
+int main(int argc, const char* argv[]) {
+  int error = 0;
+  const W_CHAR* dump_folder = TO_W_CHAR(".");
+  const W_CHAR* prefix = TO_W_CHAR("dump_");
+  const W_CHAR* suffix = TO_W_CHAR("png");
+  WebPOutputFileFormat format = PNG;
+  int c;
+
+  INIT_WARGV(argc, argv);
+
+  if (argc < 2) {
+    Help();
+    FREE_WARGV_AND_RETURN(-1);
+  }
+
+  for (c = 1; !error && c < argc; ++c) {
+    if (!strcmp(argv[c], "-folder")) {
+      if (c + 1 == argc) {
+        fprintf(stderr, "missing argument after option '%s'\n", argv[c]);
+        error = 1;
+        break;
+      }
+      dump_folder = GET_WARGV(argv, ++c);
+    } else if (!strcmp(argv[c], "-prefix")) {
+      if (c + 1 == argc) {
+        fprintf(stderr, "missing argument after option '%s'\n", argv[c]);
+        error = 1;
+        break;
+      }
+      prefix = GET_WARGV(argv, ++c);
+    } else if (!strcmp(argv[c], "-tiff")) {
+      format = TIFF;
+      suffix = TO_W_CHAR("tiff");
+    } else if (!strcmp(argv[c], "-pam")) {
+      format = PAM;
+      suffix = TO_W_CHAR("pam");
+    } else if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+      Help();
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-version")) {
+      int dec_version, demux_version;
+      GetAnimatedImageVersions(&dec_version, &demux_version);
+      printf("WebP Decoder version: %d.%d.%d\nWebP Demux version: %d.%d.%d\n",
+             (dec_version >> 16) & 0xff, (dec_version >> 8) & 0xff,
+             (dec_version >> 0) & 0xff,
+             (demux_version >> 16) & 0xff, (demux_version >> 8) & 0xff,
+             (demux_version >> 0) & 0xff);
+      FREE_WARGV_AND_RETURN(0);
+    } else {
+      uint32_t i;
+      AnimatedImage image;
+      const W_CHAR* const file = GET_WARGV(argv, c);
+      memset(&image, 0, sizeof(image));
+      WPRINTF("Decoding file: %s as %s/%sxxxx.%s\n",
+              file, dump_folder, prefix, suffix);
+      if (!ReadAnimatedImage((const char*)file, &image, 0, NULL)) {
+        WFPRINTF(stderr, "Error decoding file: %s\n Aborting.\n", file);
+        error = 1;
+        break;
+      }
+      for (i = 0; !error && i < image.num_frames; ++i) {
+        W_CHAR out_file[1024];
+        WebPDecBuffer buffer;
+        WebPInitDecBuffer(&buffer);
+        buffer.colorspace = MODE_RGBA;
+        buffer.is_external_memory = 1;
+        buffer.width = image.canvas_width;
+        buffer.height = image.canvas_height;
+        buffer.u.RGBA.rgba = image.frames[i].rgba;
+        buffer.u.RGBA.stride = buffer.width * sizeof(uint32_t);
+        buffer.u.RGBA.size = buffer.u.RGBA.stride * buffer.height;
+        WSNPRINTF(out_file, sizeof(out_file), "%s/%s%.4d.%s",
+                  dump_folder, prefix, i, suffix);
+        if (!WebPSaveImage(&buffer, format, (const char*)out_file)) {
+          WFPRINTF(stderr, "Error while saving image '%s'\n", out_file);
+          error = 1;
+        }
+        WebPFreeDecBuffer(&buffer);
+      }
+      ClearAnimatedImage(&image);
+    }
+  }
+  FREE_WARGV_AND_RETURN(error ? 1 : 0);
+}

examples/anim_util.c

@@ -0,0 +1,782 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Utilities for animated images
+
+#include "./anim_util.h"
+
+#include <assert.h>
+#include <math.h>
+#include <stdio.h>
+#include <string.h>
+
+#if defined(WEBP_HAVE_GIF)
+#include <gif_lib.h>
+#endif
+#include "webp/format_constants.h"
+#include "webp/decode.h"
+#include "webp/demux.h"
+#include "../imageio/imageio_util.h"
+#include "./gifdec.h"
+#include "./unicode.h"
+#include "./unicode_gif.h"
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf
+#endif
+
+static const int kNumChannels = 4;
+
+// -----------------------------------------------------------------------------
+// Common utilities.
+
+#if defined(WEBP_HAVE_GIF)
+// Returns true if the frame covers the full canvas.
+static int IsFullFrame(int width, int height,
+                       int canvas_width, int canvas_height) {
+  return (width == canvas_width && height == canvas_height);
+}
+#endif // WEBP_HAVE_GIF
+
+static int CheckSizeForOverflow(uint64_t size) {
+  return (size == (size_t)size);
+}
+
+static int AllocateFrames(AnimatedImage* const image, uint32_t num_frames) {
+  uint32_t i;
+  uint8_t* mem = NULL;
+  DecodedFrame* frames = NULL;
+  const uint64_t rgba_size =
+      (uint64_t)image->canvas_width * kNumChannels * image->canvas_height;
+  const uint64_t total_size = (uint64_t)num_frames * rgba_size * sizeof(*mem);
+  const uint64_t total_frame_size = (uint64_t)num_frames * sizeof(*frames);
+  if (!CheckSizeForOverflow(total_size) ||
+      !CheckSizeForOverflow(total_frame_size)) {
+    return 0;
+  }
+  mem = (uint8_t*)WebPMalloc((size_t)total_size);
+  frames = (DecodedFrame*)WebPMalloc((size_t)total_frame_size);
+
+  if (mem == NULL || frames == NULL) {
+    WebPFree(mem);
+    WebPFree(frames);
+    return 0;
+  }
+  WebPFree(image->raw_mem);
+  image->num_frames = num_frames;
+  image->frames = frames;
+  for (i = 0; i < num_frames; ++i) {
+    frames[i].rgba = mem + i * rgba_size;
+    frames[i].duration = 0;
+    frames[i].is_key_frame = 0;
+  }
+  image->raw_mem = mem;
+  return 1;
+}
+
+void ClearAnimatedImage(AnimatedImage* const image) {
+  if (image != NULL) {
+    WebPFree(image->raw_mem);
+    WebPFree(image->frames);
+    image->num_frames = 0;
+    image->frames = NULL;
+    image->raw_mem = NULL;
+  }
+}
+
+#if defined(WEBP_HAVE_GIF)
+// Clear the canvas to transparent.
+static void ZeroFillCanvas(uint8_t* rgba,
+                           uint32_t canvas_width, uint32_t canvas_height) {
+  memset(rgba, 0, canvas_width * kNumChannels * canvas_height);
+}
+
+// Clear given frame rectangle to transparent.
+static void ZeroFillFrameRect(uint8_t* rgba, int rgba_stride, int x_offset,
+                              int y_offset, int width, int height) {
+  int j;
+  assert(width * kNumChannels <= rgba_stride);
+  rgba += y_offset * rgba_stride + x_offset * kNumChannels;
+  for (j = 0; j < height; ++j) {
+    memset(rgba, 0, width * kNumChannels);
+    rgba += rgba_stride;
+  }
+}
+
+// Copy width * height pixels from 'src' to 'dst'.
+static void CopyCanvas(const uint8_t* src, uint8_t* dst,
+                       uint32_t width, uint32_t height) {
+  assert(src != NULL && dst != NULL);
+  memcpy(dst, src, width * kNumChannels * height);
+}
+
+// Copy pixels in the given rectangle from 'src' to 'dst' honoring the 'stride'.
+static void CopyFrameRectangle(const uint8_t* src, uint8_t* dst, int stride,
+                               int x_offset, int y_offset,
+                               int width, int height) {
+  int j;
+  const int width_in_bytes = width * kNumChannels;
+  const size_t offset = y_offset * stride + x_offset * kNumChannels;
+  assert(width_in_bytes <= stride);
+  src += offset;
+  dst += offset;
+  for (j = 0; j < height; ++j) {
+    memcpy(dst, src, width_in_bytes);
+    src += stride;
+    dst += stride;
+  }
+}
+#endif // WEBP_HAVE_GIF
+
+// Canonicalize all transparent pixels to transparent black to aid comparison.
+static void CleanupTransparentPixels(uint32_t* rgba,
+                                     uint32_t width, uint32_t height) {
+  const uint32_t* const rgba_end = rgba + width * height;
+  while (rgba < rgba_end) {
+    const uint8_t alpha = (*rgba >> 24) & 0xff;
+    if (alpha == 0) {
+      *rgba = 0;
+    }
+    ++rgba;
+  }
+}
+
+// Dump frame to a PAM file. Returns true on success.
+static int DumpFrame(const char filename[], const char dump_folder[],
+                     uint32_t frame_num, const uint8_t rgba[],
+                     int canvas_width, int canvas_height) {
+  int ok = 0;
+  size_t max_len;
+  int y;
+  const W_CHAR* base_name = NULL;
+  W_CHAR* file_name = NULL;
+  FILE* f = NULL;
+  const char* row;
+
+  if (dump_folder == NULL) dump_folder = (const char*)TO_W_CHAR(".");
+
+  base_name = WSTRRCHR(filename, '/');
+  base_name = (base_name == NULL) ? (const W_CHAR*)filename : base_name + 1;
+  max_len = WSTRLEN(dump_folder) + 1 + WSTRLEN(base_name)
+          + strlen("_frame_") + strlen(".pam") + 8;
+  file_name = (W_CHAR*)WebPMalloc(max_len * sizeof(*file_name));
+  if (file_name == NULL) goto End;
+
+  if (WSNPRINTF(file_name, max_len, "%s/%s_frame_%d.pam",
+                (const W_CHAR*)dump_folder, base_name, frame_num) < 0) {
+    fprintf(stderr, "Error while generating file name\n");
+    goto End;
+  }
+
+  f = WFOPEN(file_name, "wb");
+  if (f == NULL) {
+    WFPRINTF(stderr, "Error opening file for writing: %s\n", file_name);
+    ok = 0;
+    goto End;
+  }
+  if (fprintf(f, "P7\nWIDTH %d\nHEIGHT %d\n"
+              "DEPTH 4\nMAXVAL 255\nTUPLTYPE RGB_ALPHA\nENDHDR\n",
+              canvas_width, canvas_height) < 0) {
+    WFPRINTF(stderr, "Write error for file %s\n", file_name);
+    goto End;
+  }
+  row = (const char*)rgba;
+  for (y = 0; y < canvas_height; ++y) {
+    if (fwrite(row, canvas_width * kNumChannels, 1, f) != 1) {
+      WFPRINTF(stderr, "Error writing to file: %s\n", file_name);
+      goto End;
+    }
+    row += canvas_width * kNumChannels;
+  }
+  ok = 1;
+ End:
+  if (f != NULL) fclose(f);
+  WebPFree(file_name);
+  return ok;
+}
+
+// -----------------------------------------------------------------------------
+// WebP Decoding.
+
+// Returns true if this is a valid WebP bitstream.
+static int IsWebP(const WebPData* const webp_data) {
+  return (WebPGetInfo(webp_data->bytes, webp_data->size, NULL, NULL) != 0);
+}
+
+// Read animated WebP bitstream 'webp_data' into 'AnimatedImage' struct.
+static int ReadAnimatedWebP(const char filename[],
+                            const WebPData* const webp_data,
+                            AnimatedImage* const image, int dump_frames,
+                            const char dump_folder[]) {
+  int ok = 0;
+  int dump_ok = 1;
+  uint32_t frame_index = 0;
+  int prev_frame_timestamp = 0;
+  WebPAnimDecoder* dec;
+  WebPAnimInfo anim_info;
+
+  memset(image, 0, sizeof(*image));
+
+  dec = WebPAnimDecoderNew(webp_data, NULL);
+  if (dec == NULL) {
+    WFPRINTF(stderr, "Error parsing image: %s\n", (const W_CHAR*)filename);
+    goto End;
+  }
+
+  if (!WebPAnimDecoderGetInfo(dec, &anim_info)) {
+    fprintf(stderr, "Error getting global info about the animation\n");
+    goto End;
+  }
+
+  // Animation properties.
+  image->canvas_width = anim_info.canvas_width;
+  image->canvas_height = anim_info.canvas_height;
+  image->loop_count = anim_info.loop_count;
+  image->bgcolor = anim_info.bgcolor;
+
+  // Allocate frames.
+  if (!AllocateFrames(image, anim_info.frame_count)) goto End;
+
+  // Decode frames.
+  while (WebPAnimDecoderHasMoreFrames(dec)) {
+    DecodedFrame* curr_frame;
+    uint8_t* curr_rgba;
+    uint8_t* frame_rgba;
+    int timestamp;
+
+    if (!WebPAnimDecoderGetNext(dec, &frame_rgba, &timestamp)) {
+      fprintf(stderr, "Error decoding frame #%u\n", frame_index);
+      goto End;
+    }
+    assert(frame_index < anim_info.frame_count);
+    curr_frame = &image->frames[frame_index];
+    curr_rgba = curr_frame->rgba;
+    curr_frame->duration = timestamp - prev_frame_timestamp;
+    curr_frame->is_key_frame = 0;  // Unused.
+    memcpy(curr_rgba, frame_rgba,
+           image->canvas_width * kNumChannels * image->canvas_height);
+
+    // Needed only because we may want to compare with GIF later.
+    CleanupTransparentPixels((uint32_t*)curr_rgba,
+                             image->canvas_width, image->canvas_height);
+
+    if (dump_frames && dump_ok) {
+      dump_ok = DumpFrame(filename, dump_folder, frame_index, curr_rgba,
+                          image->canvas_width, image->canvas_height);
+      if (!dump_ok) {  // Print error once, but continue decode loop.
+        fprintf(stderr, "Error dumping frames to %s\n", dump_folder);
+      }
+    }
+
+    ++frame_index;
+    prev_frame_timestamp = timestamp;
+  }
+  ok = dump_ok;
+  if (ok) image->format = ANIM_WEBP;
+
+ End:
+  WebPAnimDecoderDelete(dec);
+  return ok;
+}
+
+// -----------------------------------------------------------------------------
+// GIF Decoding.
+
+#if defined(WEBP_HAVE_GIF)
+
+// Returns true if this is a valid GIF bitstream.
+static int IsGIF(const WebPData* const data) {
+  return data->size > GIF_STAMP_LEN &&
+         (!memcmp(GIF_STAMP, data->bytes, GIF_STAMP_LEN) ||
+          !memcmp(GIF87_STAMP, data->bytes, GIF_STAMP_LEN) ||
+          !memcmp(GIF89_STAMP, data->bytes, GIF_STAMP_LEN));
+}
+
+// GIFLIB_MAJOR is only defined in libgif >= 4.2.0.
+#if defined(GIFLIB_MAJOR) && defined(GIFLIB_MINOR)
+# define LOCAL_GIF_VERSION ((GIFLIB_MAJOR << 8) | GIFLIB_MINOR)
+# define LOCAL_GIF_PREREQ(maj, min) \
+    (LOCAL_GIF_VERSION >= (((maj) << 8) | (min)))
+#else
+# define LOCAL_GIF_VERSION 0
+# define LOCAL_GIF_PREREQ(maj, min) 0
+#endif
+
+#if !LOCAL_GIF_PREREQ(5, 0)
+
+// Added in v5.0
+typedef struct {
+  int DisposalMode;
+#define DISPOSAL_UNSPECIFIED      0       // No disposal specified
+#define DISPOSE_DO_NOT            1       // Leave image in place
+#define DISPOSE_BACKGROUND        2       // Set area to background color
+#define DISPOSE_PREVIOUS          3       // Restore to previous content
+  int UserInputFlag;       // User confirmation required before disposal
+  int DelayTime;           // Pre-display delay in 0.01sec units
+  int TransparentColor;    // Palette index for transparency, -1 if none
+#define NO_TRANSPARENT_COLOR     -1
+} GraphicsControlBlock;
+
+static int DGifExtensionToGCB(const size_t GifExtensionLength,
+                              const GifByteType* GifExtension,
+                              GraphicsControlBlock* gcb) {
+  if (GifExtensionLength != 4) {
+    return GIF_ERROR;
+  }
+  gcb->DisposalMode = (GifExtension[0] >> 2) & 0x07;
+  gcb->UserInputFlag = (GifExtension[0] & 0x02) != 0;
+  gcb->DelayTime = GifExtension[1] | (GifExtension[2] << 8);
+  if (GifExtension[0] & 0x01) {
+    gcb->TransparentColor = (int)GifExtension[3];
+  } else {
+    gcb->TransparentColor = NO_TRANSPARENT_COLOR;
+  }
+  return GIF_OK;
+}
+
+static int DGifSavedExtensionToGCB(GifFileType* GifFile, int ImageIndex,
+                                   GraphicsControlBlock* gcb) {
+  int i;
+  if (ImageIndex < 0 || ImageIndex > GifFile->ImageCount - 1) {
+    return GIF_ERROR;
+  }
+  gcb->DisposalMode = DISPOSAL_UNSPECIFIED;
+  gcb->UserInputFlag = 0;
+  gcb->DelayTime = 0;
+  gcb->TransparentColor = NO_TRANSPARENT_COLOR;
+
+  for (i = 0; i < GifFile->SavedImages[ImageIndex].ExtensionBlockCount; i++) {
+    ExtensionBlock* ep = &GifFile->SavedImages[ImageIndex].ExtensionBlocks[i];
+    if (ep->Function == GRAPHICS_EXT_FUNC_CODE) {
+      return DGifExtensionToGCB(
+          ep->ByteCount, (const GifByteType*)ep->Bytes, gcb);
+    }
+  }
+  return GIF_ERROR;
+}
+
+#define CONTINUE_EXT_FUNC_CODE 0x00
+
+// Signature was changed in v5.0
+#define DGifOpenFileName(a, b) DGifOpenFileName(a)
+
+#endif  // !LOCAL_GIF_PREREQ(5, 0)
+
+// Signature changed in v5.1
+#if !LOCAL_GIF_PREREQ(5, 1)
+#define DGifCloseFile(a, b) DGifCloseFile(a)
+#endif
+
+static int IsKeyFrameGIF(const GifImageDesc* prev_desc, int prev_dispose,
+                         const DecodedFrame* const prev_frame,
+                         int canvas_width, int canvas_height) {
+  if (prev_frame == NULL) return 1;
+  if (prev_dispose == DISPOSE_BACKGROUND) {
+    if (IsFullFrame(prev_desc->Width, prev_desc->Height,
+                    canvas_width, canvas_height)) {
+      return 1;
+    }
+    if (prev_frame->is_key_frame) return 1;
+  }
+  return 0;
+}
+
+static int GetTransparentIndexGIF(GifFileType* gif) {
+  GraphicsControlBlock first_gcb;
+  memset(&first_gcb, 0, sizeof(first_gcb));
+  DGifSavedExtensionToGCB(gif, 0, &first_gcb);
+  return first_gcb.TransparentColor;
+}
+
+static uint32_t GetBackgroundColorGIF(GifFileType* gif) {
+  const int transparent_index = GetTransparentIndexGIF(gif);
+  const ColorMapObject* const color_map = gif->SColorMap;
+  if (transparent_index != NO_TRANSPARENT_COLOR &&
+      gif->SBackGroundColor == transparent_index) {
+    return 0x00000000;  // Special case: transparent black.
+  } else if (color_map == NULL || color_map->Colors == NULL
+             || gif->SBackGroundColor >= color_map->ColorCount) {
+    return 0xffffffff;  // Invalid: assume white.
+  } else {
+    const GifColorType color = color_map->Colors[gif->SBackGroundColor];
+    return (0xffu << 24) |
+           (color.Red << 16) |
+           (color.Green << 8) |
+           (color.Blue << 0);
+  }
+}
+
+// Find appropriate app extension and get loop count from the next extension.
+// We use Chrome's interpretation of the 'loop_count' semantics:
+//   if not present -> loop once
+//   if present and loop_count == 0, return 0 ('infinite').
+//   if present and loop_count != 0, it's the number of *extra* loops
+//     so we need to return loop_count + 1 as total loop number.
+static uint32_t GetLoopCountGIF(const GifFileType* const gif) {
+  int i;
+  for (i = 0; i < gif->ImageCount; ++i) {
+    const SavedImage* const image = &gif->SavedImages[i];
+    int j;
+    for (j = 0; (j + 1) < image->ExtensionBlockCount; ++j) {
+      const ExtensionBlock* const eb1 = image->ExtensionBlocks + j;
+      const ExtensionBlock* const eb2 = image->ExtensionBlocks + j + 1;
+      const char* const signature = (const char*)eb1->Bytes;
+      const int signature_is_ok =
+          (eb1->Function == APPLICATION_EXT_FUNC_CODE) &&
+          (eb1->ByteCount == 11) &&
+          (!memcmp(signature, "NETSCAPE2.0", 11) ||
+           !memcmp(signature, "ANIMEXTS1.0", 11));
+      if (signature_is_ok &&
+          eb2->Function == CONTINUE_EXT_FUNC_CODE && eb2->ByteCount >= 3 &&
+          eb2->Bytes[0] == 1) {
+        const uint32_t extra_loop = ((uint32_t)(eb2->Bytes[2]) << 8) +
+                                    ((uint32_t)(eb2->Bytes[1]) << 0);
+        return (extra_loop > 0) ? extra_loop + 1 : 0;
+      }
+    }
+  }
+  return 1;  // Default.
+}
+
+// Get duration of 'n'th frame in milliseconds.
+static int GetFrameDurationGIF(GifFileType* gif, int n) {
+  GraphicsControlBlock gcb;
+  memset(&gcb, 0, sizeof(gcb));
+  DGifSavedExtensionToGCB(gif, n, &gcb);
+  return gcb.DelayTime * 10;
+}
+
+// Returns true if frame 'target' completely covers 'covered'.
+static int CoversFrameGIF(const GifImageDesc* const target,
+                          const GifImageDesc* const covered) {
+  return target->Left <= covered->Left &&
+         covered->Left + covered->Width <= target->Left + target->Width &&
+         target->Top <= covered->Top &&
+         covered->Top + covered->Height <= target->Top + target->Height;
+}
+
+static void RemapPixelsGIF(const uint8_t* const src,
+                           const ColorMapObject* const cmap,
+                           int transparent_color, int len, uint8_t* dst) {
+  int i;
+  for (i = 0; i < len; ++i) {
+    if (src[i] != transparent_color) {
+      // If a pixel in the current frame is transparent, we don't modify it, so
+      // that we can see-through the corresponding pixel from an earlier frame.
+      const GifColorType c = cmap->Colors[src[i]];
+      dst[4 * i + 0] = c.Red;
+      dst[4 * i + 1] = c.Green;
+      dst[4 * i + 2] = c.Blue;
+      dst[4 * i + 3] = 0xff;
+    }
+  }
+}
+
+static int ReadFrameGIF(const SavedImage* const gif_image,
+                        const ColorMapObject* cmap, int transparent_color,
+                        int out_stride, uint8_t* const dst) {
+  const GifImageDesc* image_desc = &gif_image->ImageDesc;
+  const uint8_t* in;
+  uint8_t* out;
+  int j;
+
+  if (image_desc->ColorMap) cmap = image_desc->ColorMap;
+
+  if (cmap == NULL || cmap->ColorCount != (1 << cmap->BitsPerPixel)) {
+    fprintf(stderr, "Potentially corrupt color map.\n");
+    return 0;
+  }
+
+  in = (const uint8_t*)gif_image->RasterBits;
+  out = dst + image_desc->Top * out_stride + image_desc->Left * kNumChannels;
+
+  for (j = 0; j < image_desc->Height; ++j) {
+    RemapPixelsGIF(in, cmap, transparent_color, image_desc->Width, out);
+    in += image_desc->Width;
+    out += out_stride;
+  }
+  return 1;
+}
+
+// Read animated GIF bitstream from 'filename' into 'AnimatedImage' struct.
+static int ReadAnimatedGIF(const char filename[], AnimatedImage* const image,
+                           int dump_frames, const char dump_folder[]) {
+  uint32_t frame_count;
+  uint32_t canvas_width, canvas_height;
+  uint32_t i;
+  int gif_error;
+  GifFileType* gif;
+
+  gif = DGifOpenFileUnicode((const W_CHAR*)filename, NULL);
+  if (gif == NULL) {
+    WFPRINTF(stderr, "Could not read file: %s.\n", (const W_CHAR*)filename);
+    return 0;
+  }
+
+  gif_error = DGifSlurp(gif);
+  if (gif_error != GIF_OK) {
+    WFPRINTF(stderr, "Could not parse image: %s.\n", (const W_CHAR*)filename);
+    GIFDisplayError(gif, gif_error);
+    DGifCloseFile(gif, NULL);
+    return 0;
+  }
+
+  // Animation properties.
+  image->canvas_width = (uint32_t)gif->SWidth;
+  image->canvas_height = (uint32_t)gif->SHeight;
+  if (image->canvas_width > MAX_CANVAS_SIZE ||
+      image->canvas_height > MAX_CANVAS_SIZE) {
+    fprintf(stderr, "Invalid canvas dimension: %d x %d\n",
+            image->canvas_width, image->canvas_height);
+    DGifCloseFile(gif, NULL);
+    return 0;
+  }
+  image->loop_count = GetLoopCountGIF(gif);
+  image->bgcolor = GetBackgroundColorGIF(gif);
+
+  frame_count = (uint32_t)gif->ImageCount;
+  if (frame_count == 0) {
+    DGifCloseFile(gif, NULL);
+    return 0;
+  }
+
+  if (image->canvas_width == 0 || image->canvas_height == 0) {
+    image->canvas_width = gif->SavedImages[0].ImageDesc.Width;
+    image->canvas_height = gif->SavedImages[0].ImageDesc.Height;
+    gif->SavedImages[0].ImageDesc.Left = 0;
+    gif->SavedImages[0].ImageDesc.Top = 0;
+    if (image->canvas_width == 0 || image->canvas_height == 0) {
+      fprintf(stderr, "Invalid canvas size in GIF.\n");
+      DGifCloseFile(gif, NULL);
+      return 0;
+    }
+  }
+  // Allocate frames.
+  if (!AllocateFrames(image, frame_count)) {
+    DGifCloseFile(gif, NULL);
+    return 0;
+  }
+
+  canvas_width = image->canvas_width;
+  canvas_height = image->canvas_height;
+
+  // Decode and reconstruct frames.
+  for (i = 0; i < frame_count; ++i) {
+    const int canvas_width_in_bytes = canvas_width * kNumChannels;
+    const SavedImage* const curr_gif_image = &gif->SavedImages[i];
+    GraphicsControlBlock curr_gcb;
+    DecodedFrame* curr_frame;
+    uint8_t* curr_rgba;
+
+    memset(&curr_gcb, 0, sizeof(curr_gcb));
+    DGifSavedExtensionToGCB(gif, i, &curr_gcb);
+
+    curr_frame = &image->frames[i];
+    curr_rgba = curr_frame->rgba;
+    curr_frame->duration = GetFrameDurationGIF(gif, i);
+    // Force frames with a small or no duration to 100ms to be consistent
+    // with web browsers and other transcoding tools (like gif2webp itself).
+    if (curr_frame->duration <= 10) curr_frame->duration = 100;
+
+    if (i == 0) {  // Initialize as transparent.
+      curr_frame->is_key_frame = 1;
+      ZeroFillCanvas(curr_rgba, canvas_width, canvas_height);
+    } else {
+      DecodedFrame* const prev_frame = &image->frames[i - 1];
+      const GifImageDesc* const prev_desc = &gif->SavedImages[i - 1].ImageDesc;
+      GraphicsControlBlock prev_gcb;
+      memset(&prev_gcb, 0, sizeof(prev_gcb));
+      DGifSavedExtensionToGCB(gif, i - 1, &prev_gcb);
+
+      curr_frame->is_key_frame =
+          IsKeyFrameGIF(prev_desc, prev_gcb.DisposalMode, prev_frame,
+                        canvas_width, canvas_height);
+
+      if (curr_frame->is_key_frame) {  // Initialize as transparent.
+        ZeroFillCanvas(curr_rgba, canvas_width, canvas_height);
+      } else {
+        int prev_frame_disposed, curr_frame_opaque;
+        int prev_frame_completely_covered;
+        // Initialize with previous canvas.
+        uint8_t* const prev_rgba = image->frames[i - 1].rgba;
+        CopyCanvas(prev_rgba, curr_rgba, canvas_width, canvas_height);
+
+        // Dispose previous frame rectangle.
+        prev_frame_disposed =
+            (prev_gcb.DisposalMode == DISPOSE_BACKGROUND ||
+             prev_gcb.DisposalMode == DISPOSE_PREVIOUS);
+        curr_frame_opaque =
+            (curr_gcb.TransparentColor == NO_TRANSPARENT_COLOR);
+        prev_frame_completely_covered =
+            curr_frame_opaque &&
+            CoversFrameGIF(&curr_gif_image->ImageDesc, prev_desc);
+
+        if (prev_frame_disposed && !prev_frame_completely_covered) {
+          switch (prev_gcb.DisposalMode) {
+            case DISPOSE_BACKGROUND: {
+              ZeroFillFrameRect(curr_rgba, canvas_width_in_bytes,
+                                prev_desc->Left, prev_desc->Top,
+                                prev_desc->Width, prev_desc->Height);
+              break;
+            }
+            case DISPOSE_PREVIOUS: {
+              int src_frame_num = i - 2;
+              while (src_frame_num >= 0) {
+                GraphicsControlBlock src_frame_gcb;
+                memset(&src_frame_gcb, 0, sizeof(src_frame_gcb));
+                DGifSavedExtensionToGCB(gif, src_frame_num, &src_frame_gcb);
+                if (src_frame_gcb.DisposalMode != DISPOSE_PREVIOUS) break;
+                --src_frame_num;
+              }
+              if (src_frame_num >= 0) {
+                // Restore pixels inside previous frame rectangle to
+                // corresponding pixels in source canvas.
+                uint8_t* const src_frame_rgba =
+                    image->frames[src_frame_num].rgba;
+                CopyFrameRectangle(src_frame_rgba, curr_rgba,
+                                   canvas_width_in_bytes,
+                                   prev_desc->Left, prev_desc->Top,
+                                   prev_desc->Width, prev_desc->Height);
+              } else {
+                // Source canvas doesn't exist. So clear previous frame
+                // rectangle to background.
+                ZeroFillFrameRect(curr_rgba, canvas_width_in_bytes,
+                                  prev_desc->Left, prev_desc->Top,
+                                  prev_desc->Width, prev_desc->Height);
+              }
+              break;
+            }
+            default:
+              break;  // Nothing to do.
+          }
+        }
+      }
+    }
+
+    // Decode current frame.
+    if (!ReadFrameGIF(curr_gif_image, gif->SColorMap, curr_gcb.TransparentColor,
+                      canvas_width_in_bytes, curr_rgba)) {
+      DGifCloseFile(gif, NULL);
+      return 0;
+    }
+
+    if (dump_frames) {
+      if (!DumpFrame(filename, dump_folder, i, curr_rgba,
+                     canvas_width, canvas_height)) {
+        DGifCloseFile(gif, NULL);
+        return 0;
+      }
+    }
+  }
+  image->format = ANIM_GIF;
+  DGifCloseFile(gif, NULL);
+  return 1;
+}
+
+#else
+
+static int IsGIF(const WebPData* const data) {
+  (void)data;
+  return 0;
+}
+
+static int ReadAnimatedGIF(const char filename[], AnimatedImage* const image,
+                           int dump_frames, const char dump_folder[]) {
+  (void)filename;
+  (void)image;
+  (void)dump_frames;
+  (void)dump_folder;
+  fprintf(stderr, "GIF support not compiled. Please install the libgif-dev "
+          "package before building.\n");
+  return 0;
+}
+
+#endif  // WEBP_HAVE_GIF
+
+// -----------------------------------------------------------------------------
+
+int ReadAnimatedImage(const char filename[], AnimatedImage* const image,
+                      int dump_frames, const char dump_folder[]) {
+  int ok = 0;
+  WebPData webp_data;
+
+  WebPDataInit(&webp_data);
+  memset(image, 0, sizeof(*image));
+
+  if (!ImgIoUtilReadFile(filename, &webp_data.bytes, &webp_data.size)) {
+    WFPRINTF(stderr, "Error reading file: %s\n", (const W_CHAR*)filename);
+    return 0;
+  }
+
+  if (IsWebP(&webp_data)) {
+    ok = ReadAnimatedWebP(filename, &webp_data, image, dump_frames,
+                          dump_folder);
+  } else if (IsGIF(&webp_data)) {
+    ok = ReadAnimatedGIF(filename, image, dump_frames, dump_folder);
+  } else {
+    WFPRINTF(stderr,
+             "Unknown file type: %s. Supported file types are WebP and GIF\n",
+             (const W_CHAR*)filename);
+    ok = 0;
+  }
+  if (!ok) ClearAnimatedImage(image);
+  WebPDataClear(&webp_data);
+  return ok;
+}
+
+static void Accumulate(double v1, double v2, double* const max_diff,
+                       double* const sse) {
+  const double diff = fabs(v1 - v2);
+  if (diff > *max_diff) *max_diff = diff;
+  *sse += diff * diff;
+}
+
+void GetDiffAndPSNR(const uint8_t rgba1[], const uint8_t rgba2[],
+                    uint32_t width, uint32_t height, int premultiply,
+                    int* const max_diff, double* const psnr) {
+  const uint32_t stride = width * kNumChannels;
+  const int kAlphaChannel = kNumChannels - 1;
+  double f_max_diff = 0.;
+  double sse = 0.;
+  uint32_t x, y;
+  for (y = 0; y < height; ++y) {
+    for (x = 0; x < stride; x += kNumChannels) {
+      int k;
+      const size_t offset = (size_t)y * stride + x;
+      const int alpha1 = rgba1[offset + kAlphaChannel];
+      const int alpha2 = rgba2[offset + kAlphaChannel];
+      Accumulate(alpha1, alpha2, &f_max_diff, &sse);
+      if (!premultiply) {
+        for (k = 0; k < kAlphaChannel; ++k) {
+          Accumulate(rgba1[offset + k], rgba2[offset + k], &f_max_diff, &sse);
+        }
+      } else {
+        // premultiply R/G/B channels with alpha value
+        for (k = 0; k < kAlphaChannel; ++k) {
+          Accumulate(rgba1[offset + k] * alpha1 / 255.,
+                     rgba2[offset + k] * alpha2 / 255.,
+                     &f_max_diff, &sse);
+        }
+      }
+    }
+  }
+  *max_diff = (int)f_max_diff;
+  if (*max_diff == 0) {
+    *psnr = 99.;  // PSNR when images are identical.
+  } else {
+    sse /= stride * height;
+    *psnr = 4.3429448 * log(255. * 255. / sse);
+  }
+}
+
+void GetAnimatedImageVersions(int* const decoder_version,
+                              int* const demux_version) {
+  *decoder_version = WebPGetDecoderVersion();
+  *demux_version = WebPGetDemuxVersion();
+}

examples/anim_util.h

@@ -0,0 +1,73 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Utilities for animated images
+
+#ifndef WEBP_EXAMPLES_ANIM_UTIL_H_
+#define WEBP_EXAMPLES_ANIM_UTIL_H_
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+  ANIM_GIF,
+  ANIM_WEBP
+} AnimatedFileFormat;
+
+typedef struct {
+  uint8_t* rgba;         // Decoded and reconstructed full frame.
+  int duration;          // Frame duration in milliseconds.
+  int is_key_frame;      // True if this frame is a key-frame.
+} DecodedFrame;
+
+typedef struct {
+  AnimatedFileFormat format;
+  uint32_t canvas_width;
+  uint32_t canvas_height;
+  uint32_t bgcolor;
+  uint32_t loop_count;
+  DecodedFrame* frames;
+  uint32_t num_frames;
+  void* raw_mem;
+} AnimatedImage;
+
+// Deallocate everything in 'image' (but not the object itself).
+void ClearAnimatedImage(AnimatedImage* const image);
+
+// Read animated image file into 'AnimatedImage' struct.
+// If 'dump_frames' is true, dump frames to 'dump_folder'.
+// Previous content of 'image' is obliterated.
+// Upon successful return, content of 'image' must be deleted by
+// calling 'ClearAnimatedImage'.
+int ReadAnimatedImage(const char filename[], AnimatedImage* const image,
+                      int dump_frames, const char dump_folder[]);
+
+// Given two RGBA buffers, calculate max pixel difference and PSNR.
+// If 'premultiply' is true, R/G/B values will be pre-multiplied by the
+// transparency before comparison.
+void GetDiffAndPSNR(const uint8_t rgba1[], const uint8_t rgba2[],
+                    uint32_t width, uint32_t height, int premultiply,
+                    int* const max_diff, double* const psnr);
+
+// Return library versions used by anim_util.
+void GetAnimatedImageVersions(int* const decoder_version,
+                              int* const demux_version);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_EXAMPLES_ANIM_UTIL_H_

examples/dwebp.c

@@ -0,0 +1,421 @@
+// Copyright 2010 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Command-line tool for decoding a WebP image.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "../examples/example_util.h"
+#include "../imageio/image_enc.h"
+#include "../imageio/webpdec.h"
+#include "./stopwatch.h"
+#include "./unicode.h"
+
+static int verbose = 0;
+static int quiet = 0;
+#ifndef WEBP_DLL
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern void* VP8GetCPUInfo;   // opaque forward declaration.
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+#endif  // WEBP_DLL
+
+
+static int SaveOutput(const WebPDecBuffer* const buffer,
+                      WebPOutputFileFormat format, const char* const out_file) {
+  const int use_stdout = (out_file != NULL) && !WSTRCMP(out_file, "-");
+  int ok = 1;
+  Stopwatch stop_watch;
+
+  if (verbose) {
+    StopwatchReset(&stop_watch);
+  }
+  ok = WebPSaveImage(buffer, format, out_file);
+
+  if (ok) {
+    if (!quiet) {
+      if (use_stdout) {
+        fprintf(stderr, "Saved to stdout\n");
+      } else {
+        WFPRINTF(stderr, "Saved file %s\n", (const W_CHAR*)out_file);
+      }
+    }
+    if (verbose) {
+      const double write_time = StopwatchReadAndReset(&stop_watch);
+      fprintf(stderr, "Time to write output: %.3fs\n", write_time);
+    }
+  } else {
+    if (use_stdout) {
+      fprintf(stderr, "Error writing to stdout !!\n");
+    } else {
+      WFPRINTF(stderr, "Error writing file %s !!\n", (const W_CHAR*)out_file);
+    }
+  }
+  return ok;
+}
+
+static void Help(void) {
+  printf("Usage: dwebp in_file [options] [-o out_file]\n\n"
+         "Decodes the WebP image file to PNG format [Default].\n"
+         "Note: Animated WebP files are not supported.\n\n"
+         "Use following options to convert into alternate image formats:\n"
+         "  -pam ......... save the raw RGBA samples as a color PAM\n"
+         "  -ppm ......... save the raw RGB samples as a color PPM\n"
+         "  -bmp ......... save as uncompressed BMP format\n"
+         "  -tiff ........ save as uncompressed TIFF format\n"
+         "  -pgm ......... save the raw YUV samples as a grayscale PGM\n"
+         "                 file with IMC4 layout\n"
+         "  -yuv ......... save the raw YUV samples in flat layout\n"
+         "\n"
+         " Other options are:\n"
+         "  -version ..... print version number and exit\n"
+         "  -nofancy ..... don't use the fancy YUV420 upscaler\n"
+         "  -nofilter .... disable in-loop filtering\n"
+         "  -nodither .... disable dithering\n"
+         "  -dither <d> .. dithering strength (in 0..100)\n"
+         "  -alpha_dither  use alpha-plane dithering if needed\n"
+         "  -mt .......... use multi-threading\n"
+         "  -crop <x> <y> <w> <h> ... crop output with the given rectangle\n"
+         "  -resize <w> <h> ......... resize output (*after* any cropping)\n"
+         "  -flip ........ flip the output vertically\n"
+         "  -alpha ....... only save the alpha plane\n"
+         "  -incremental . use incremental decoding (useful for tests)\n"
+         "  -h ........... this help message\n"
+         "  -v ........... verbose (e.g. print encoding/decoding times)\n"
+         "  -quiet ....... quiet mode, don't print anything\n"
+#ifndef WEBP_DLL
+         "  -noasm ....... disable all assembly optimizations\n"
+#endif
+        );
+}
+
+static const char* const kFormatType[] = {
+  "unspecified", "lossy", "lossless"
+};
+
+static uint8_t* AllocateExternalBuffer(WebPDecoderConfig* config,
+                                       WebPOutputFileFormat format,
+                                       int use_external_memory) {
+  uint8_t* external_buffer = NULL;
+  WebPDecBuffer* const output_buffer = &config->output;
+  int w = config->input.width;
+  int h = config->input.height;
+  if (config->options.use_scaling) {
+    w = config->options.scaled_width;
+    h = config->options.scaled_height;
+  } else if (config->options.use_cropping) {
+    w = config->options.crop_width;
+    h = config->options.crop_height;
+  }
+  if (format >= RGB && format <= rgbA_4444) {
+    const int bpp = (format == RGB || format == BGR) ? 3
+                  : (format == RGBA_4444 || format == rgbA_4444 ||
+                     format == RGB_565) ? 2
+                  : 4;
+    uint32_t stride = bpp * w + 7;   // <- just for exercising
+    external_buffer = (uint8_t*)WebPMalloc(stride * h);
+    if (external_buffer == NULL) return NULL;
+    output_buffer->u.RGBA.stride = stride;
+    output_buffer->u.RGBA.size = stride * h;
+    output_buffer->u.RGBA.rgba = external_buffer;
+  } else {    // YUV and YUVA
+    const int has_alpha = WebPIsAlphaMode(output_buffer->colorspace);
+    uint8_t* tmp;
+    uint32_t stride = w + 3;
+    uint32_t uv_stride = (w + 1) / 2 + 13;
+    uint32_t total_size = stride * h * (has_alpha ? 2 : 1)
+                        + 2 * uv_stride * (h + 1) / 2;
+    assert(format >= YUV && format <= YUVA);
+    external_buffer = (uint8_t*)WebPMalloc(total_size);
+    if (external_buffer == NULL) return NULL;
+    tmp = external_buffer;
+    output_buffer->u.YUVA.y = tmp;
+    output_buffer->u.YUVA.y_stride = stride;
+    output_buffer->u.YUVA.y_size = stride * h;
+    tmp += output_buffer->u.YUVA.y_size;
+    if (has_alpha) {
+      output_buffer->u.YUVA.a = tmp;
+      output_buffer->u.YUVA.a_stride = stride;
+      output_buffer->u.YUVA.a_size = stride * h;
+      tmp += output_buffer->u.YUVA.a_size;
+    } else {
+      output_buffer->u.YUVA.a = NULL;
+      output_buffer->u.YUVA.a_stride = 0;
+    }
+    output_buffer->u.YUVA.u = tmp;
+    output_buffer->u.YUVA.u_stride = uv_stride;
+    output_buffer->u.YUVA.u_size = uv_stride * (h + 1) / 2;
+    tmp += output_buffer->u.YUVA.u_size;
+
+    output_buffer->u.YUVA.v = tmp;
+    output_buffer->u.YUVA.v_stride = uv_stride;
+    output_buffer->u.YUVA.v_size = uv_stride * (h + 1) / 2;
+    tmp += output_buffer->u.YUVA.v_size;
+    assert(tmp <= external_buffer + total_size);
+  }
+  output_buffer->is_external_memory = use_external_memory;
+  return external_buffer;
+}
+
+int main(int argc, const char* argv[]) {
+  int ok = 0;
+  const char* in_file = NULL;
+  const char* out_file = NULL;
+
+  WebPDecoderConfig config;
+  WebPDecBuffer* const output_buffer = &config.output;
+  WebPBitstreamFeatures* const bitstream = &config.input;
+  WebPOutputFileFormat format = PNG;
+  uint8_t* external_buffer = NULL;
+  int use_external_memory = 0;
+  const uint8_t* data = NULL;
+
+  int incremental = 0;
+  int c;
+
+  INIT_WARGV(argc, argv);
+
+  if (!WebPInitDecoderConfig(&config)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    FREE_WARGV_AND_RETURN(-1);
+  }
+
+  for (c = 1; c < argc; ++c) {
+    int parse_error = 0;
+    if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+      Help();
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-o") && c < argc - 1) {
+      out_file = (const char*)GET_WARGV(argv, ++c);
+    } else if (!strcmp(argv[c], "-alpha")) {
+      format = ALPHA_PLANE_ONLY;
+    } else if (!strcmp(argv[c], "-nofancy")) {
+      config.options.no_fancy_upsampling = 1;
+    } else if (!strcmp(argv[c], "-nofilter")) {
+      config.options.bypass_filtering = 1;
+    } else if (!strcmp(argv[c], "-pam")) {
+      format = PAM;
+    } else if (!strcmp(argv[c], "-ppm")) {
+      format = PPM;
+    } else if (!strcmp(argv[c], "-bmp")) {
+      format = BMP;
+    } else if (!strcmp(argv[c], "-tiff")) {
+      format = TIFF;
+    } else if (!strcmp(argv[c], "-quiet")) {
+      quiet = 1;
+    } else if (!strcmp(argv[c], "-version")) {
+      const int version = WebPGetDecoderVersion();
+      printf("%d.%d.%d\n",
+             (version >> 16) & 0xff, (version >> 8) & 0xff, version & 0xff);
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-pgm")) {
+      format = PGM;
+    } else if (!strcmp(argv[c], "-yuv")) {
+      format = RAW_YUV;
+    } else if (!strcmp(argv[c], "-pixel_format") && c < argc - 1) {
+      const char* const fmt = argv[++c];
+      if      (!strcmp(fmt, "RGB"))  format = RGB;
+      else if (!strcmp(fmt, "RGBA")) format = RGBA;
+      else if (!strcmp(fmt, "BGR"))  format = BGR;
+      else if (!strcmp(fmt, "BGRA")) format = BGRA;
+      else if (!strcmp(fmt, "ARGB")) format = ARGB;
+      else if (!strcmp(fmt, "RGBA_4444")) format = RGBA_4444;
+      else if (!strcmp(fmt, "RGB_565")) format = RGB_565;
+      else if (!strcmp(fmt, "rgbA")) format = rgbA;
+      else if (!strcmp(fmt, "bgrA")) format = bgrA;
+      else if (!strcmp(fmt, "Argb")) format = Argb;
+      else if (!strcmp(fmt, "rgbA_4444")) format = rgbA_4444;
+      else if (!strcmp(fmt, "YUV"))  format = YUV;
+      else if (!strcmp(fmt, "YUVA")) format = YUVA;
+      else {
+        fprintf(stderr, "Can't parse pixel_format %s\n", fmt);
+        parse_error = 1;
+      }
+    } else if (!strcmp(argv[c], "-external_memory") && c < argc - 1) {
+      use_external_memory = ExUtilGetInt(argv[++c], 0, &parse_error);
+      parse_error |= (use_external_memory > 2 || use_external_memory < 0);
+      if (parse_error) {
+        fprintf(stderr, "Can't parse 'external_memory' value %s\n", argv[c]);
+      }
+    } else if (!strcmp(argv[c], "-mt")) {
+      config.options.use_threads = 1;
+    } else if (!strcmp(argv[c], "-alpha_dither")) {
+      config.options.alpha_dithering_strength = 100;
+    } else if (!strcmp(argv[c], "-nodither")) {
+      config.options.dithering_strength = 0;
+    } else if (!strcmp(argv[c], "-dither") && c < argc - 1) {
+      config.options.dithering_strength =
+          ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if (!strcmp(argv[c], "-crop") && c < argc - 4) {
+      config.options.use_cropping = 1;
+      config.options.crop_left   = ExUtilGetInt(argv[++c], 0, &parse_error);
+      config.options.crop_top    = ExUtilGetInt(argv[++c], 0, &parse_error);
+      config.options.crop_width  = ExUtilGetInt(argv[++c], 0, &parse_error);
+      config.options.crop_height = ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if ((!strcmp(argv[c], "-scale") || !strcmp(argv[c], "-resize")) &&
+               c < argc - 2) {  // '-scale' is left for compatibility
+      config.options.use_scaling = 1;
+      config.options.scaled_width  = ExUtilGetInt(argv[++c], 0, &parse_error);
+      config.options.scaled_height = ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if (!strcmp(argv[c], "-flip")) {
+      config.options.flip = 1;
+    } else if (!strcmp(argv[c], "-v")) {
+      verbose = 1;
+#ifndef WEBP_DLL
+    } else if (!strcmp(argv[c], "-noasm")) {
+      VP8GetCPUInfo = NULL;
+#endif
+    } else if (!strcmp(argv[c], "-incremental")) {
+      incremental = 1;
+    } else if (!strcmp(argv[c], "--")) {
+      if (c < argc - 1) in_file = (const char*)GET_WARGV(argv, ++c);
+      break;
+    } else if (argv[c][0] == '-') {
+      fprintf(stderr, "Unknown option '%s'\n", argv[c]);
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    } else {
+      in_file = (const char*)GET_WARGV(argv, c);
+    }
+
+    if (parse_error) {
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    }
+  }
+
+  if (in_file == NULL) {
+    fprintf(stderr, "missing input file!!\n");
+    Help();
+    FREE_WARGV_AND_RETURN(-1);
+  }
+
+  if (quiet) verbose = 0;
+
+  {
+    VP8StatusCode status = VP8_STATUS_OK;
+    size_t data_size = 0;
+    if (!LoadWebP(in_file, &data, &data_size, bitstream)) {
+      FREE_WARGV_AND_RETURN(-1);
+    }
+
+    switch (format) {
+      case PNG:
+#ifdef HAVE_WINCODEC_H
+        output_buffer->colorspace = bitstream->has_alpha ? MODE_BGRA : MODE_BGR;
+#else
+        output_buffer->colorspace = bitstream->has_alpha ? MODE_RGBA : MODE_RGB;
+#endif
+        break;
+      case PAM:
+        output_buffer->colorspace = MODE_RGBA;
+        break;
+      case PPM:
+        output_buffer->colorspace = MODE_RGB;  // drops alpha for PPM
+        break;
+      case BMP:
+        output_buffer->colorspace = bitstream->has_alpha ? MODE_BGRA : MODE_BGR;
+        break;
+      case TIFF:
+        output_buffer->colorspace = bitstream->has_alpha ? MODE_RGBA : MODE_RGB;
+        break;
+      case PGM:
+      case RAW_YUV:
+        output_buffer->colorspace = bitstream->has_alpha ? MODE_YUVA : MODE_YUV;
+        break;
+      case ALPHA_PLANE_ONLY:
+        output_buffer->colorspace = MODE_YUVA;
+        break;
+      // forced modes:
+      case RGB: output_buffer->colorspace = MODE_RGB; break;
+      case RGBA: output_buffer->colorspace = MODE_RGBA; break;
+      case BGR: output_buffer->colorspace = MODE_BGR; break;
+      case BGRA: output_buffer->colorspace = MODE_BGRA; break;
+      case ARGB: output_buffer->colorspace = MODE_ARGB; break;
+      case RGBA_4444: output_buffer->colorspace = MODE_RGBA_4444; break;
+      case RGB_565: output_buffer->colorspace = MODE_RGB_565; break;
+      case rgbA: output_buffer->colorspace = MODE_rgbA; break;
+      case bgrA: output_buffer->colorspace = MODE_bgrA; break;
+      case Argb: output_buffer->colorspace = MODE_Argb; break;
+      case rgbA_4444: output_buffer->colorspace = MODE_rgbA_4444; break;
+      case YUV: output_buffer->colorspace = MODE_YUV; break;
+      case YUVA: output_buffer->colorspace = MODE_YUVA; break;
+      default: goto Exit;
+    }
+
+    if (use_external_memory > 0 && format >= RGB) {
+      external_buffer = AllocateExternalBuffer(&config, format,
+                                               use_external_memory);
+      if (external_buffer == NULL) goto Exit;
+    }
+
+    {
+      Stopwatch stop_watch;
+      if (verbose) StopwatchReset(&stop_watch);
+
+      if (incremental) {
+        status = DecodeWebPIncremental(data, data_size, &config);
+      } else {
+        status = DecodeWebP(data, data_size, &config);
+      }
+      if (verbose) {
+        const double decode_time = StopwatchReadAndReset(&stop_watch);
+        fprintf(stderr, "Time to decode picture: %.3fs\n", decode_time);
+      }
+    }
+
+    ok = (status == VP8_STATUS_OK);
+    if (!ok) {
+      PrintWebPError(in_file, status);
+      goto Exit;
+    }
+  }
+
+  if (out_file != NULL) {
+    if (!quiet) {
+      WFPRINTF(stderr, "Decoded %s.", (const W_CHAR*)in_file);
+      fprintf(stderr, " Dimensions: %d x %d %s. Format: %s. Now saving...\n",
+              output_buffer->width, output_buffer->height,
+              bitstream->has_alpha ? " (with alpha)" : "",
+              kFormatType[bitstream->format]);
+    }
+    ok = SaveOutput(output_buffer, format, out_file);
+  } else {
+    if (!quiet) {
+      WFPRINTF(stderr, "File %s can be decoded ", (const W_CHAR*)in_file);
+      fprintf(stderr, "(dimensions: %d x %d %s. Format: %s).\n",
+              output_buffer->width, output_buffer->height,
+              bitstream->has_alpha ? " (with alpha)" : "",
+              kFormatType[bitstream->format]);
+      fprintf(stderr, "Nothing written; "
+                      "use -o flag to save the result as e.g. PNG.\n");
+    }
+  }
+ Exit:
+  WebPFreeDecBuffer(output_buffer);
+  WebPFree((void*)external_buffer);
+  WebPFree((void*)data);
+  FREE_WARGV_AND_RETURN(ok ? 0 : -1);
+}
+
+//------------------------------------------------------------------------------

examples/example_util.c

@@ -0,0 +1,139 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Utility functions used by the example programs.
+//
+
+#include "./example_util.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/mux_types.h"
+#include "../imageio/imageio_util.h"
+
+//------------------------------------------------------------------------------
+// String parsing
+
+uint32_t ExUtilGetUInt(const char* const v, int base, int* const error) {
+  char* end = NULL;
+  const uint32_t n = (v != NULL) ? (uint32_t)strtoul(v, &end, base) : 0u;
+  if (end == v && error != NULL && !*error) {
+    *error = 1;
+    fprintf(stderr, "Error! '%s' is not an integer.\n",
+            (v != NULL) ? v : "(null)");
+  }
+  return n;
+}
+
+int ExUtilGetInt(const char* const v, int base, int* const error) {
+  return (int)ExUtilGetUInt(v, base, error);
+}
+
+int ExUtilGetInts(const char* v, int base, int max_output, int output[]) {
+  int n, error = 0;
+  for (n = 0; v != NULL && n < max_output; ++n) {
+    const int value = ExUtilGetInt(v, base, &error);
+    if (error) return -1;
+    output[n] = value;
+    v = strchr(v, ',');
+    if (v != NULL) ++v;   // skip over the trailing ','
+  }
+  return n;
+}
+
+float ExUtilGetFloat(const char* const v, int* const error) {
+  char* end = NULL;
+  const float f = (v != NULL) ? (float)strtod(v, &end) : 0.f;
+  if (end == v && error != NULL && !*error) {
+    *error = 1;
+    fprintf(stderr, "Error! '%s' is not a floating point number.\n",
+            (v != NULL) ? v : "(null)");
+  }
+  return f;
+}
+
+//------------------------------------------------------------------------------
+
+static void ResetCommandLineArguments(int argc, const char* argv[],
+                                      CommandLineArguments* const args) {
+  assert(args != NULL);
+  args->argc_ = argc;
+  args->argv_ = argv;
+  args->own_argv_ = 0;
+  WebPDataInit(&args->argv_data_);
+}
+
+void ExUtilDeleteCommandLineArguments(CommandLineArguments* const args) {
+  if (args != NULL) {
+    if (args->own_argv_) {
+      WebPFree((void*)args->argv_);
+      WebPDataClear(&args->argv_data_);
+    }
+    ResetCommandLineArguments(0, NULL, args);
+  }
+}
+
+#define MAX_ARGC 16384
+int ExUtilInitCommandLineArguments(int argc, const char* argv[],
+                                   CommandLineArguments* const args) {
+  if (args == NULL || argv == NULL) return 0;
+  ResetCommandLineArguments(argc, argv, args);
+  if (argc == 1 && argv[0][0] != '-') {
+    char* cur;
+    const char sep[] = " \t\r\n\f\v";
+
+#if defined(_WIN32) && defined(_UNICODE)
+    fprintf(stderr,
+            "Error: Reading arguments from a file is a feature unavailable "
+            "with Unicode binaries.\n");
+    return 0;
+#endif
+
+    if (!ExUtilReadFileToWebPData(argv[0], &args->argv_data_)) {
+      return 0;
+    }
+    args->own_argv_ = 1;
+    args->argv_ = (const char**)WebPMalloc(MAX_ARGC * sizeof(*args->argv_));
+    if (args->argv_ == NULL) {
+      ExUtilDeleteCommandLineArguments(args);
+      return 0;
+    }
+
+    argc = 0;
+    for (cur = strtok((char*)args->argv_data_.bytes, sep);
+         cur != NULL;
+         cur = strtok(NULL, sep)) {
+      if (argc == MAX_ARGC) {
+        fprintf(stderr, "ERROR: Arguments limit %d reached\n", MAX_ARGC);
+        ExUtilDeleteCommandLineArguments(args);
+        return 0;
+      }
+      assert(strlen(cur) != 0);
+      args->argv_[argc++] = cur;
+    }
+    args->argc_ = argc;
+  }
+  return 1;
+}
+
+//------------------------------------------------------------------------------
+
+int ExUtilReadFileToWebPData(const char* const filename,
+                             WebPData* const webp_data) {
+  const uint8_t* data;
+  size_t size;
+  if (webp_data == NULL) return 0;
+  if (!ImgIoUtilReadFile(filename, &data, &size)) return 0;
+  webp_data->bytes = data;
+  webp_data->size = size;
+  return 1;
+}

examples/example_util.h

@@ -0,0 +1,70 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Utility functions used by the example programs.
+//
+
+#ifndef WEBP_EXAMPLES_EXAMPLE_UTIL_H_
+#define WEBP_EXAMPLES_EXAMPLE_UTIL_H_
+
+#include "webp/types.h"
+#include "webp/mux_types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+//------------------------------------------------------------------------------
+// String parsing
+
+// Parses 'v' using strto(ul|l|d)(). If error is non-NULL, '*error' is set to
+// true on failure while on success it is left unmodified to allow chaining of
+// calls. An error is only printed on the first occurrence.
+uint32_t ExUtilGetUInt(const char* const v, int base, int* const error);
+int ExUtilGetInt(const char* const v, int base, int* const error);
+float ExUtilGetFloat(const char* const v, int* const error);
+
+// This variant of ExUtilGetInt() will parse multiple integers from a
+// comma-separated list. Up to 'max_output' integers are parsed.
+// The result is placed in the output[] array, and the number of integers
+// actually parsed is returned, or -1 if an error occurred.
+int ExUtilGetInts(const char* v, int base, int max_output, int output[]);
+
+// Reads a file named 'filename' into a WebPData structure. The content of
+// webp_data is overwritten. Returns false in case of error.
+int ExUtilReadFileToWebPData(const char* const filename,
+                             WebPData* const webp_data);
+
+//------------------------------------------------------------------------------
+// Command-line arguments
+
+typedef struct {
+  int argc_;
+  const char** argv_;
+  WebPData argv_data_;
+  int own_argv_;
+} CommandLineArguments;
+
+// Initializes the structure from the command-line parameters. If there is
+// only one parameter and it does not start with a '-', then it is assumed to
+// be a file name. This file will be read and tokenized into command-line
+// arguments. The content of 'args' is overwritten.
+// Returns false in case of error (memory allocation failure, non
+// existing file, too many arguments, ...).
+int ExUtilInitCommandLineArguments(int argc, const char* argv[],
+                                   CommandLineArguments* const args);
+
+// Deallocate all memory and reset 'args'.
+void ExUtilDeleteCommandLineArguments(CommandLineArguments* const args);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_EXAMPLES_EXAMPLE_UTIL_H_

examples/gif2webp.c

@@ -0,0 +1,609 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  simple tool to convert animated GIFs to WebP
+//
+// Authors: Skal (pascal.massimino@gmail.com)
+//          Urvang (urvang@google.com)
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#ifdef WEBP_HAVE_GIF
+
+#if defined(HAVE_UNISTD_H) && HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include <gif_lib.h>
+#include "webp/encode.h"
+#include "webp/mux.h"
+#include "../examples/example_util.h"
+#include "../imageio/imageio_util.h"
+#include "./gifdec.h"
+#include "./unicode.h"
+#include "./unicode_gif.h"
+
+#if !defined(STDIN_FILENO)
+#define STDIN_FILENO 0
+#endif
+
+//------------------------------------------------------------------------------
+
+static int transparent_index = GIF_INDEX_INVALID;  // Opaque by default.
+
+static const char* const kErrorMessages[-WEBP_MUX_NOT_ENOUGH_DATA + 1] = {
+  "WEBP_MUX_NOT_FOUND", "WEBP_MUX_INVALID_ARGUMENT", "WEBP_MUX_BAD_DATA",
+  "WEBP_MUX_MEMORY_ERROR", "WEBP_MUX_NOT_ENOUGH_DATA"
+};
+
+static const char* ErrorString(WebPMuxError err) {
+  assert(err <= WEBP_MUX_NOT_FOUND && err >= WEBP_MUX_NOT_ENOUGH_DATA);
+  return kErrorMessages[-err];
+}
+
+enum {
+  METADATA_ICC  = (1 << 0),
+  METADATA_XMP  = (1 << 1),
+  METADATA_ALL  = METADATA_ICC | METADATA_XMP
+};
+
+//------------------------------------------------------------------------------
+
+static void Help(void) {
+  printf("Usage:\n");
+  printf(" gif2webp [options] gif_file -o webp_file\n");
+  printf("Options:\n");
+  printf("  -h / -help ............. this help\n");
+  printf("  -lossy ................. encode image using lossy compression\n");
+  printf("  -mixed ................. for each frame in the image, pick lossy\n"
+         "                           or lossless compression heuristically\n");
+  printf("  -q <float> ............. quality factor (0:small..100:big)\n");
+  printf("  -m <int> ............... compression method (0=fast, 6=slowest)\n");
+  printf("  -min_size .............. minimize output size (default:off)\n"
+         "                           lossless compression by default; can be\n"
+         "                           combined with -q, -m, -lossy or -mixed\n"
+         "                           options\n");
+  printf("  -kmin <int> ............ min distance between key frames\n");
+  printf("  -kmax <int> ............ max distance between key frames\n");
+  printf("  -f <int> ............... filter strength (0=off..100)\n");
+  printf("  -metadata <string> ..... comma separated list of metadata to\n");
+  printf("                           ");
+  printf("copy from the input to the output if present\n");
+  printf("                           ");
+  printf("Valid values: all, none, icc, xmp (default)\n");
+  printf("  -loop_compatibility .... use compatibility mode for Chrome\n");
+  printf("                           version prior to M62 (inclusive)\n");
+  printf("  -mt .................... use multi-threading if available\n");
+  printf("\n");
+  printf("  -version ............... print version number and exit\n");
+  printf("  -v ..................... verbose\n");
+  printf("  -quiet ................. don't print anything\n");
+  printf("\n");
+}
+
+//------------------------------------------------------------------------------
+
+int main(int argc, const char* argv[]) {
+  int verbose = 0;
+  int gif_error = GIF_ERROR;
+  WebPMuxError err = WEBP_MUX_OK;
+  int ok = 0;
+  const W_CHAR* in_file = NULL, *out_file = NULL;
+  GifFileType* gif = NULL;
+  int frame_duration = 0;
+  int frame_timestamp = 0;
+  GIFDisposeMethod orig_dispose = GIF_DISPOSE_NONE;
+
+  WebPPicture frame;                // Frame rectangle only (not disposed).
+  WebPPicture curr_canvas;          // Not disposed.
+  WebPPicture prev_canvas;          // Disposed.
+
+  WebPAnimEncoder* enc = NULL;
+  WebPAnimEncoderOptions enc_options;
+  WebPConfig config;
+
+  int frame_number = 0;     // Whether we are processing the first frame.
+  int done;
+  int c;
+  int quiet = 0;
+  WebPData webp_data;
+
+  int keep_metadata = METADATA_XMP;  // ICC not output by default.
+  WebPData icc_data;
+  int stored_icc = 0;         // Whether we have already stored an ICC profile.
+  WebPData xmp_data;
+  int stored_xmp = 0;         // Whether we have already stored an XMP profile.
+  int loop_count = 0;         // default: infinite
+  int stored_loop_count = 0;  // Whether we have found an explicit loop count.
+  int loop_compatibility = 0;
+  WebPMux* mux = NULL;
+
+  int default_kmin = 1;  // Whether to use default kmin value.
+  int default_kmax = 1;
+
+  INIT_WARGV(argc, argv);
+
+  if (!WebPConfigInit(&config) || !WebPAnimEncoderOptionsInit(&enc_options) ||
+      !WebPPictureInit(&frame) || !WebPPictureInit(&curr_canvas) ||
+      !WebPPictureInit(&prev_canvas)) {
+    fprintf(stderr, "Error! Version mismatch!\n");
+    FREE_WARGV_AND_RETURN(-1);
+  }
+  config.lossless = 1;  // Use lossless compression by default.
+
+  WebPDataInit(&webp_data);
+  WebPDataInit(&icc_data);
+  WebPDataInit(&xmp_data);
+
+  if (argc == 1) {
+    Help();
+    FREE_WARGV_AND_RETURN(0);
+  }
+
+  for (c = 1; c < argc; ++c) {
+    int parse_error = 0;
+    if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+      Help();
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-o") && c < argc - 1) {
+      out_file = GET_WARGV(argv, ++c);
+    } else if (!strcmp(argv[c], "-lossy")) {
+      config.lossless = 0;
+    } else if (!strcmp(argv[c], "-mixed")) {
+      enc_options.allow_mixed = 1;
+      config.lossless = 0;
+    } else if (!strcmp(argv[c], "-loop_compatibility")) {
+      loop_compatibility = 1;
+    } else if (!strcmp(argv[c], "-q") && c < argc - 1) {
+      config.quality = ExUtilGetFloat(argv[++c], &parse_error);
+    } else if (!strcmp(argv[c], "-m") && c < argc - 1) {
+      config.method = ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if (!strcmp(argv[c], "-min_size")) {
+      enc_options.minimize_size = 1;
+    } else if (!strcmp(argv[c], "-kmax") && c < argc - 1) {
+      enc_options.kmax = ExUtilGetInt(argv[++c], 0, &parse_error);
+      default_kmax = 0;
+    } else if (!strcmp(argv[c], "-kmin") && c < argc - 1) {
+      enc_options.kmin = ExUtilGetInt(argv[++c], 0, &parse_error);
+      default_kmin = 0;
+    } else if (!strcmp(argv[c], "-f") && c < argc - 1) {
+      config.filter_strength = ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if (!strcmp(argv[c], "-metadata") && c < argc - 1) {
+      static const struct {
+        const char* option;
+        int flag;
+      } kTokens[] = {
+        { "all",  METADATA_ALL },
+        { "none", 0 },
+        { "icc",  METADATA_ICC },
+        { "xmp",  METADATA_XMP },
+      };
+      const size_t kNumTokens = sizeof(kTokens) / sizeof(*kTokens);
+      const char* start = argv[++c];
+      const char* const end = start + strlen(start);
+
+      keep_metadata = 0;
+      while (start < end) {
+        size_t i;
+        const char* token = strchr(start, ',');
+        if (token == NULL) token = end;
+
+        for (i = 0; i < kNumTokens; ++i) {
+          if ((size_t)(token - start) == strlen(kTokens[i].option) &&
+              !strncmp(start, kTokens[i].option, strlen(kTokens[i].option))) {
+            if (kTokens[i].flag != 0) {
+              keep_metadata |= kTokens[i].flag;
+            } else {
+              keep_metadata = 0;
+            }
+            break;
+          }
+        }
+        if (i == kNumTokens) {
+          fprintf(stderr, "Error! Unknown metadata type '%.*s'\n",
+                  (int)(token - start), start);
+          Help();
+          FREE_WARGV_AND_RETURN(-1);
+        }
+        start = token + 1;
+      }
+    } else if (!strcmp(argv[c], "-mt")) {
+      ++config.thread_level;
+    } else if (!strcmp(argv[c], "-version")) {
+      const int enc_version = WebPGetEncoderVersion();
+      const int mux_version = WebPGetMuxVersion();
+      printf("WebP Encoder version: %d.%d.%d\nWebP Mux version: %d.%d.%d\n",
+             (enc_version >> 16) & 0xff, (enc_version >> 8) & 0xff,
+             enc_version & 0xff, (mux_version >> 16) & 0xff,
+             (mux_version >> 8) & 0xff, mux_version & 0xff);
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-quiet")) {
+      quiet = 1;
+      enc_options.verbose = 0;
+    } else if (!strcmp(argv[c], "-v")) {
+      verbose = 1;
+      enc_options.verbose = 1;
+    } else if (!strcmp(argv[c], "--")) {
+      if (c < argc - 1) in_file = GET_WARGV(argv, ++c);
+      break;
+    } else if (argv[c][0] == '-') {
+      fprintf(stderr, "Error! Unknown option '%s'\n", argv[c]);
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    } else {
+      in_file = GET_WARGV(argv, c);
+    }
+
+    if (parse_error) {
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    }
+  }
+
+  // Appropriate default kmin, kmax values for lossy and lossless.
+  if (default_kmin) {
+    enc_options.kmin = config.lossless ? 9 : 3;
+  }
+  if (default_kmax) {
+    enc_options.kmax = config.lossless ? 17 : 5;
+  }
+
+  if (!WebPValidateConfig(&config)) {
+    fprintf(stderr, "Error! Invalid configuration.\n");
+    goto End;
+  }
+
+  if (in_file == NULL) {
+    fprintf(stderr, "No input file specified!\n");
+    Help();
+    goto End;
+  }
+
+  // Start the decoder object
+  gif = DGifOpenFileUnicode(in_file, &gif_error);
+  if (gif == NULL) goto End;
+
+  // Loop over GIF images
+  done = 0;
+  do {
+    GifRecordType type;
+    if (DGifGetRecordType(gif, &type) == GIF_ERROR) goto End;
+
+    switch (type) {
+      case IMAGE_DESC_RECORD_TYPE: {
+        GIFFrameRect gif_rect;
+        GifImageDesc* const image_desc = &gif->Image;
+
+        if (!DGifGetImageDesc(gif)) goto End;
+
+        if (frame_number == 0) {
+          if (verbose) {
+            printf("Canvas screen: %d x %d\n", gif->SWidth, gif->SHeight);
+          }
+          // Fix some broken GIF global headers that report
+          // 0 x 0 screen dimension.
+          if (gif->SWidth == 0 || gif->SHeight == 0) {
+            image_desc->Left = 0;
+            image_desc->Top = 0;
+            gif->SWidth = image_desc->Width;
+            gif->SHeight = image_desc->Height;
+            if (gif->SWidth <= 0 || gif->SHeight <= 0) {
+              goto End;
+            }
+            if (verbose) {
+              printf("Fixed canvas screen dimension to: %d x %d\n",
+                     gif->SWidth, gif->SHeight);
+            }
+          }
+          // Allocate current buffer.
+          frame.width = gif->SWidth;
+          frame.height = gif->SHeight;
+          frame.use_argb = 1;
+          if (!WebPPictureAlloc(&frame)) goto End;
+          GIFClearPic(&frame, NULL);
+          if (!(WebPPictureCopy(&frame, &curr_canvas) &&
+                WebPPictureCopy(&frame, &prev_canvas))) {
+            fprintf(stderr, "Error allocating canvas.\n");
+            goto End;
+          }
+
+          // Background color.
+          GIFGetBackgroundColor(gif->SColorMap, gif->SBackGroundColor,
+                                transparent_index,
+                                &enc_options.anim_params.bgcolor);
+
+          // Initialize encoder.
+          enc = WebPAnimEncoderNew(curr_canvas.width, curr_canvas.height,
+                                   &enc_options);
+          if (enc == NULL) {
+            fprintf(stderr,
+                    "Error! Could not create encoder object. Possibly due to "
+                    "a memory error.\n");
+            goto End;
+          }
+        }
+
+        // Some even more broken GIF can have sub-rect with zero width/height.
+        if (image_desc->Width == 0 || image_desc->Height == 0) {
+          image_desc->Width = gif->SWidth;
+          image_desc->Height = gif->SHeight;
+        }
+
+        if (!GIFReadFrame(gif, transparent_index, &gif_rect, &frame)) {
+          goto End;
+        }
+        // Blend frame rectangle with previous canvas to compose full canvas.
+        // Note that 'curr_canvas' is same as 'prev_canvas' at this point.
+        GIFBlendFrames(&frame, &gif_rect, &curr_canvas);
+
+        if (!WebPAnimEncoderAdd(enc, &curr_canvas, frame_timestamp, &config)) {
+          fprintf(stderr, "Error while adding frame #%d: %s\n", frame_number,
+                  WebPAnimEncoderGetError(enc));
+          goto End;
+        } else {
+          ++frame_number;
+        }
+
+        // Update canvases.
+        GIFDisposeFrame(orig_dispose, &gif_rect, &prev_canvas, &curr_canvas);
+        GIFCopyPixels(&curr_canvas, &prev_canvas);
+
+        // Force frames with a small or no duration to 100ms to be consistent
+        // with web browsers and other transcoding tools. This also avoids
+        // incorrect durations between frames when padding frames are
+        // discarded.
+        if (frame_duration <= 10) {
+          frame_duration = 100;
+        }
+
+        // Update timestamp (for next frame).
+        frame_timestamp += frame_duration;
+
+        // In GIF, graphic control extensions are optional for a frame, so we
+        // may not get one before reading the next frame. To handle this case,
+        // we reset frame properties to reasonable defaults for the next frame.
+        orig_dispose = GIF_DISPOSE_NONE;
+        frame_duration = 0;
+        transparent_index = GIF_INDEX_INVALID;
+        break;
+      }
+      case EXTENSION_RECORD_TYPE: {
+        int extension;
+        GifByteType* data = NULL;
+        if (DGifGetExtension(gif, &extension, &data) == GIF_ERROR) {
+          goto End;
+        }
+        if (data == NULL) continue;
+
+        switch (extension) {
+          case COMMENT_EXT_FUNC_CODE: {
+            break;  // Do nothing for now.
+          }
+          case GRAPHICS_EXT_FUNC_CODE: {
+            if (!GIFReadGraphicsExtension(data, &frame_duration, &orig_dispose,
+                                          &transparent_index)) {
+              goto End;
+            }
+            break;
+          }
+          case PLAINTEXT_EXT_FUNC_CODE: {
+            break;
+          }
+          case APPLICATION_EXT_FUNC_CODE: {
+            if (data[0] != 11) break;    // Chunk is too short
+            if (!memcmp(data + 1, "NETSCAPE2.0", 11) ||
+                !memcmp(data + 1, "ANIMEXTS1.0", 11)) {
+              if (!GIFReadLoopCount(gif, &data, &loop_count)) {
+                goto End;
+              }
+              if (verbose) {
+                fprintf(stderr, "Loop count: %d\n", loop_count);
+              }
+              stored_loop_count = loop_compatibility ? (loop_count != 0) : 1;
+            } else {  // An extension containing metadata.
+              // We only store the first encountered chunk of each type, and
+              // only if requested by the user.
+              const int is_xmp = (keep_metadata & METADATA_XMP) &&
+                                 !stored_xmp &&
+                                 !memcmp(data + 1, "XMP DataXMP", 11);
+              const int is_icc = (keep_metadata & METADATA_ICC) &&
+                                 !stored_icc &&
+                                 !memcmp(data + 1, "ICCRGBG1012", 11);
+              if (is_xmp || is_icc) {
+                if (!GIFReadMetadata(gif, &data,
+                                     is_xmp ? &xmp_data : &icc_data)) {
+                  goto End;
+                }
+                if (is_icc) {
+                  stored_icc = 1;
+                } else if (is_xmp) {
+                  stored_xmp = 1;
+                }
+              }
+            }
+            break;
+          }
+          default: {
+            break;  // skip
+          }
+        }
+        while (data != NULL) {
+          if (DGifGetExtensionNext(gif, &data) == GIF_ERROR) goto End;
+        }
+        break;
+      }
+      case TERMINATE_RECORD_TYPE: {
+        done = 1;
+        break;
+      }
+      default: {
+        if (verbose) {
+          fprintf(stderr, "Skipping over unknown record type %d\n", type);
+        }
+        break;
+      }
+    }
+  } while (!done);
+
+  // Last NULL frame.
+  if (!WebPAnimEncoderAdd(enc, NULL, frame_timestamp, NULL)) {
+    fprintf(stderr, "Error flushing WebP muxer.\n");
+    fprintf(stderr, "%s\n", WebPAnimEncoderGetError(enc));
+  }
+
+  if (!WebPAnimEncoderAssemble(enc, &webp_data)) {
+    fprintf(stderr, "%s\n", WebPAnimEncoderGetError(enc));
+    goto End;
+  }
+  // If there's only one frame, we don't need to handle loop count.
+  if (frame_number == 1) {
+    loop_count = 0;
+  } else if (!loop_compatibility) {
+    if (!stored_loop_count) {
+      // if no loop-count element is seen, the default is '1' (loop-once)
+      // and we need to signal it explicitly in WebP. Note however that
+      // in case there's a single frame, we still don't need to store it.
+      if (frame_number > 1) {
+        stored_loop_count = 1;
+        loop_count = 1;
+      }
+    } else if (loop_count > 0 && loop_count < 65535) {
+      // adapt GIF's semantic to WebP's (except in the infinite-loop case)
+      loop_count += 1;
+    }
+  }
+  // loop_count of 0 is the default (infinite), so no need to signal it
+  if (loop_count == 0) stored_loop_count = 0;
+
+  if (stored_loop_count || stored_icc || stored_xmp) {
+    // Re-mux to add loop count and/or metadata as needed.
+    mux = WebPMuxCreate(&webp_data, 1);
+    if (mux == NULL) {
+      fprintf(stderr, "ERROR: Could not re-mux to add loop count/metadata.\n");
+      goto End;
+    }
+    WebPDataClear(&webp_data);
+
+    if (stored_loop_count) {  // Update loop count.
+      WebPMuxAnimParams new_params;
+      err = WebPMuxGetAnimationParams(mux, &new_params);
+      if (err != WEBP_MUX_OK) {
+        fprintf(stderr, "ERROR (%s): Could not fetch loop count.\n",
+                ErrorString(err));
+        goto End;
+      }
+      new_params.loop_count = loop_count;
+      err = WebPMuxSetAnimationParams(mux, &new_params);
+      if (err != WEBP_MUX_OK) {
+        fprintf(stderr, "ERROR (%s): Could not update loop count.\n",
+                ErrorString(err));
+        goto End;
+      }
+    }
+
+    if (stored_icc) {   // Add ICCP chunk.
+      err = WebPMuxSetChunk(mux, "ICCP", &icc_data, 1);
+      if (verbose) {
+        fprintf(stderr, "ICC size: %d\n", (int)icc_data.size);
+      }
+      if (err != WEBP_MUX_OK) {
+        fprintf(stderr, "ERROR (%s): Could not set ICC chunk.\n",
+                ErrorString(err));
+        goto End;
+      }
+    }
+
+    if (stored_xmp) {   // Add XMP chunk.
+      err = WebPMuxSetChunk(mux, "XMP ", &xmp_data, 1);
+      if (verbose) {
+        fprintf(stderr, "XMP size: %d\n", (int)xmp_data.size);
+      }
+      if (err != WEBP_MUX_OK) {
+        fprintf(stderr, "ERROR (%s): Could not set XMP chunk.\n",
+                ErrorString(err));
+        goto End;
+      }
+    }
+
+    err = WebPMuxAssemble(mux, &webp_data);
+    if (err != WEBP_MUX_OK) {
+      fprintf(stderr, "ERROR (%s): Could not assemble when re-muxing to add "
+              "loop count/metadata.\n", ErrorString(err));
+      goto End;
+    }
+  }
+
+  if (out_file != NULL) {
+    if (!ImgIoUtilWriteFile((const char*)out_file, webp_data.bytes,
+                            webp_data.size)) {
+      WFPRINTF(stderr, "Error writing output file: %s\n", out_file);
+      goto End;
+    }
+    if (!quiet) {
+      if (!WSTRCMP(out_file, "-")) {
+        fprintf(stderr, "Saved %d bytes to STDIO\n",
+                (int)webp_data.size);
+      } else {
+        WFPRINTF(stderr, "Saved output file (%d bytes): %s\n",
+                 (int)webp_data.size, out_file);
+      }
+    }
+  } else {
+    if (!quiet) {
+      fprintf(stderr, "Nothing written; use -o flag to save the result "
+                      "(%d bytes).\n", (int)webp_data.size);
+    }
+  }
+
+  // All OK.
+  ok = 1;
+  gif_error = GIF_OK;
+
+ End:
+  WebPDataClear(&icc_data);
+  WebPDataClear(&xmp_data);
+  WebPMuxDelete(mux);
+  WebPDataClear(&webp_data);
+  WebPPictureFree(&frame);
+  WebPPictureFree(&curr_canvas);
+  WebPPictureFree(&prev_canvas);
+  WebPAnimEncoderDelete(enc);
+
+  if (gif_error != GIF_OK) {
+    GIFDisplayError(gif, gif_error);
+  }
+  if (gif != NULL) {
+#if LOCAL_GIF_PREREQ(5,1)
+    DGifCloseFile(gif, &gif_error);
+#else
+    DGifCloseFile(gif);
+#endif
+  }
+
+  FREE_WARGV_AND_RETURN(!ok);
+}
+
+#else  // !WEBP_HAVE_GIF
+
+int main(int argc, const char* argv[]) {
+  fprintf(stderr, "GIF support not enabled in %s.\n", argv[0]);
+  (void)argc;
+  return 0;
+}
+
+#endif
+
+//------------------------------------------------------------------------------

examples/gifdec.c

@@ -0,0 +1,416 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// GIF decode.
+
+#include "./gifdec.h"
+
+#include <stdio.h>
+
+#ifdef WEBP_HAVE_GIF
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/encode.h"
+#include "webp/mux_types.h"
+
+#define GIF_TRANSPARENT_COLOR 0x00000000u
+#define GIF_WHITE_COLOR       0xffffffffu
+#define GIF_TRANSPARENT_MASK  0x01
+#define GIF_DISPOSE_MASK      0x07
+#define GIF_DISPOSE_SHIFT     2
+
+// from utils/utils.h
+#ifdef __cplusplus
+extern "C" {
+#endif
+extern void WebPCopyPlane(const uint8_t* src, int src_stride,
+                          uint8_t* dst, int dst_stride,
+                          int width, int height);
+extern void WebPCopyPixels(const WebPPicture* const src,
+                           WebPPicture* const dst);
+#ifdef __cplusplus
+}
+#endif
+
+void GIFGetBackgroundColor(const ColorMapObject* const color_map,
+                           int bgcolor_index, int transparent_index,
+                           uint32_t* const bgcolor) {
+  if (transparent_index != GIF_INDEX_INVALID &&
+      bgcolor_index == transparent_index) {
+    *bgcolor = GIF_TRANSPARENT_COLOR;  // Special case.
+  } else if (color_map == NULL || color_map->Colors == NULL
+             || bgcolor_index >= color_map->ColorCount) {
+    *bgcolor = GIF_WHITE_COLOR;
+    fprintf(stderr,
+            "GIF decode warning: invalid background color index. Assuming "
+            "white background.\n");
+  } else {
+    const GifColorType color = color_map->Colors[bgcolor_index];
+    *bgcolor = (0xffu       << 24)
+             | (color.Red   << 16)
+             | (color.Green <<  8)
+             | (color.Blue  <<  0);
+  }
+}
+
+int GIFReadGraphicsExtension(const GifByteType* const buf, int* const duration,
+                             GIFDisposeMethod* const dispose,
+                             int* const transparent_index) {
+  const int flags = buf[1];
+  const int dispose_raw = (flags >> GIF_DISPOSE_SHIFT) & GIF_DISPOSE_MASK;
+  const int duration_raw = buf[2] | (buf[3] << 8);  // In 10 ms units.
+  if (buf[0] != 4) return 0;
+  *duration = duration_raw * 10;  // Duration is in 1 ms units.
+  switch (dispose_raw) {
+    case 3:
+      *dispose = GIF_DISPOSE_RESTORE_PREVIOUS;
+      break;
+    case 2:
+      *dispose = GIF_DISPOSE_BACKGROUND;
+      break;
+    case 1:
+    case 0:
+    default:
+      *dispose = GIF_DISPOSE_NONE;
+      break;
+  }
+  *transparent_index =
+      (flags & GIF_TRANSPARENT_MASK) ? buf[4] : GIF_INDEX_INVALID;
+  return 1;
+}
+
+static int Remap(const GifFileType* const gif, const uint8_t* const src,
+                 int len, int transparent_index, uint32_t* dst) {
+  int i;
+  const GifColorType* colors;
+  const ColorMapObject* const cmap =
+      gif->Image.ColorMap ? gif->Image.ColorMap : gif->SColorMap;
+  if (cmap == NULL) return 1;
+  if (cmap->Colors == NULL || cmap->ColorCount <= 0) return 0;
+  colors = cmap->Colors;
+
+  for (i = 0; i < len; ++i) {
+    if (src[i] == transparent_index) {
+      dst[i] = GIF_TRANSPARENT_COLOR;
+    } else if (src[i] < cmap->ColorCount) {
+      const GifColorType c = colors[src[i]];
+      dst[i] = c.Blue | (c.Green << 8) | (c.Red << 16) | (0xffu << 24);
+    } else {
+      return 0;
+    }
+  }
+  return 1;
+}
+
+int GIFReadFrame(GifFileType* const gif, int transparent_index,
+                 GIFFrameRect* const gif_rect, WebPPicture* const picture) {
+  WebPPicture sub_image;
+  const GifImageDesc* const image_desc = &gif->Image;
+  uint32_t* dst = NULL;
+  uint8_t* tmp = NULL;
+  const GIFFrameRect rect = {
+      image_desc->Left, image_desc->Top, image_desc->Width, image_desc->Height
+  };
+  const uint64_t memory_needed = 4 * rect.width * (uint64_t)rect.height;
+  int ok = 0;
+  *gif_rect = rect;
+
+  if (memory_needed != (size_t)memory_needed || memory_needed > (4ULL << 32)) {
+    fprintf(stderr, "Image is too large (%d x %d).", rect.width, rect.height);
+    return 0;
+  }
+
+  // Use a view for the sub-picture:
+  if (!WebPPictureView(picture, rect.x_offset, rect.y_offset,
+                       rect.width, rect.height, &sub_image)) {
+    fprintf(stderr, "Sub-image %dx%d at position %d,%d is invalid!\n",
+            rect.width, rect.height, rect.x_offset, rect.y_offset);
+    return 0;
+  }
+  dst = sub_image.argb;
+
+  tmp = (uint8_t*)WebPMalloc(rect.width * sizeof(*tmp));
+  if (tmp == NULL) goto End;
+
+  if (image_desc->Interlace) {  // Interlaced image.
+    // We need 4 passes, with the following offsets and jumps.
+    const int interlace_offsets[] = { 0, 4, 2, 1 };
+    const int interlace_jumps[]   = { 8, 8, 4, 2 };
+    int pass;
+    for (pass = 0; pass < 4; ++pass) {
+      const size_t stride = (size_t)sub_image.argb_stride;
+      int y = interlace_offsets[pass];
+      uint32_t* row = dst + y * stride;
+      const size_t jump = interlace_jumps[pass] * stride;
+      for (; y < rect.height; y += interlace_jumps[pass], row += jump) {
+        if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;
+        if (!Remap(gif, tmp, rect.width, transparent_index, row)) goto End;
+      }
+    }
+  } else {  // Non-interlaced image.
+    int y;
+    uint32_t* ptr = dst;
+    for (y = 0; y < rect.height; ++y, ptr += sub_image.argb_stride) {
+      if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;
+      if (!Remap(gif, tmp, rect.width, transparent_index, ptr)) goto End;
+    }
+  }
+  ok = 1;
+
+ End:
+  if (!ok) picture->error_code = sub_image.error_code;
+  WebPPictureFree(&sub_image);
+  WebPFree(tmp);
+  return ok;
+}
+
+int GIFReadLoopCount(GifFileType* const gif, GifByteType** const buf,
+                     int* const loop_count) {
+  assert(!memcmp(*buf + 1, "NETSCAPE2.0", 11) ||
+         !memcmp(*buf + 1, "ANIMEXTS1.0", 11));
+  if (DGifGetExtensionNext(gif, buf) == GIF_ERROR) {
+    return 0;
+  }
+  if (*buf == NULL) {
+    return 0;  // Loop count sub-block missing.
+  }
+  if ((*buf)[0] < 3 || (*buf)[1] != 1) {
+    return 0;   // wrong size/marker
+  }
+  *loop_count = (*buf)[2] | ((*buf)[3] << 8);
+  return 1;
+}
+
+int GIFReadMetadata(GifFileType* const gif, GifByteType** const buf,
+                    WebPData* const metadata) {
+  const int is_xmp = !memcmp(*buf + 1, "XMP DataXMP", 11);
+  const int is_icc = !memcmp(*buf + 1, "ICCRGBG1012", 11);
+  assert(is_xmp || is_icc);
+  (void)is_icc;  // silence unused warning.
+  // Construct metadata from sub-blocks.
+  // Usual case (including ICC profile): In each sub-block, the
+  // first byte specifies its size in bytes (0 to 255) and the
+  // rest of the bytes contain the data.
+  // Special case for XMP data: In each sub-block, the first byte
+  // is also part of the XMP payload. XMP in GIF also has a 257
+  // byte padding data. See the XMP specification for details.
+  while (1) {
+    WebPData subblock;
+    const uint8_t* tmp;
+    if (DGifGetExtensionNext(gif, buf) == GIF_ERROR) {
+      return 0;
+    }
+    if (*buf == NULL) break;  // Finished.
+    subblock.size = is_xmp ? (*buf)[0] + 1 : (*buf)[0];
+    assert(subblock.size > 0);
+    subblock.bytes = is_xmp ? *buf : *buf + 1;
+    // Note: We store returned value in 'tmp' first, to avoid
+    // leaking old memory in metadata->bytes on error.
+    tmp = (uint8_t*)realloc((void*)metadata->bytes,
+                            metadata->size + subblock.size);
+    if (tmp == NULL) {
+      return 0;
+    }
+    memcpy((void*)(tmp + metadata->size),
+           subblock.bytes, subblock.size);
+    metadata->bytes = tmp;
+    metadata->size += subblock.size;
+  }
+  if (is_xmp) {
+    // XMP padding data is 0x01, 0xff, 0xfe ... 0x01, 0x00.
+    const size_t xmp_pading_size = 257;
+    if (metadata->size > xmp_pading_size) {
+      metadata->size -= xmp_pading_size;
+    }
+  }
+  return 1;
+}
+
+static void ClearRectangle(WebPPicture* const picture,
+                           int left, int top, int width, int height) {
+  int i, j;
+  const size_t stride = picture->argb_stride;
+  uint32_t* dst = picture->argb + top * stride + left;
+  for (j = 0; j < height; ++j, dst += stride) {
+    for (i = 0; i < width; ++i) dst[i] = GIF_TRANSPARENT_COLOR;
+  }
+}
+
+void GIFClearPic(WebPPicture* const pic, const GIFFrameRect* const rect) {
+  if (rect != NULL) {
+    ClearRectangle(pic, rect->x_offset, rect->y_offset,
+                   rect->width, rect->height);
+  } else {
+    ClearRectangle(pic, 0, 0, pic->width, pic->height);
+  }
+}
+
+void GIFCopyPixels(const WebPPicture* const src, WebPPicture* const dst) {
+  WebPCopyPixels(src, dst);
+}
+
+void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,
+                     const WebPPicture* const prev_canvas,
+                     WebPPicture* const curr_canvas) {
+  assert(rect != NULL);
+  if (dispose == GIF_DISPOSE_BACKGROUND) {
+    GIFClearPic(curr_canvas, rect);
+  } else if (dispose == GIF_DISPOSE_RESTORE_PREVIOUS) {
+    const size_t src_stride = prev_canvas->argb_stride;
+    const uint32_t* const src = prev_canvas->argb + rect->x_offset
+                              + rect->y_offset * src_stride;
+    const size_t dst_stride = curr_canvas->argb_stride;
+    uint32_t* const dst = curr_canvas->argb + rect->x_offset
+                        + rect->y_offset * dst_stride;
+    assert(prev_canvas != NULL);
+    WebPCopyPlane((uint8_t*)src, (int)(4 * src_stride),
+                  (uint8_t*)dst, (int)(4 * dst_stride),
+                  4 * rect->width, rect->height);
+  }
+}
+
+void GIFBlendFrames(const WebPPicture* const src,
+                    const GIFFrameRect* const rect, WebPPicture* const dst) {
+  int i, j;
+  const size_t src_stride = src->argb_stride;
+  const size_t dst_stride = dst->argb_stride;
+  assert(src->width == dst->width && src->height == dst->height);
+  for (j = rect->y_offset; j < rect->y_offset + rect->height; ++j) {
+    for (i = rect->x_offset; i < rect->x_offset + rect->width; ++i) {
+      const uint32_t src_pixel = src->argb[j * src_stride + i];
+      const int src_alpha = src_pixel >> 24;
+      if (src_alpha != 0) {
+        dst->argb[j * dst_stride + i] = src_pixel;
+      }
+    }
+  }
+}
+
+void GIFDisplayError(const GifFileType* const gif, int gif_error) {
+  // libgif 4.2.0 has retired PrintGifError() and added GifErrorString().
+#if LOCAL_GIF_PREREQ(4,2)
+#if LOCAL_GIF_PREREQ(5,0)
+  // Static string actually, hence the const char* cast.
+  const char* error_str = (const char*)GifErrorString(
+      (gif == NULL) ? gif_error : gif->Error);
+#else
+  const char* error_str = (const char*)GifErrorString();
+  (void)gif;
+#endif
+  if (error_str == NULL) error_str = "Unknown error";
+  fprintf(stderr, "GIFLib Error %d: %s\n", gif_error, error_str);
+#else
+  (void)gif;
+  fprintf(stderr, "GIFLib Error %d: ", gif_error);
+  PrintGifError();
+  fprintf(stderr, "\n");
+#endif
+}
+
+#else  // !WEBP_HAVE_GIF
+
+static void ErrorGIFNotAvailable() {
+  fprintf(stderr, "GIF support not compiled. Please install the libgif-dev "
+          "package before building.\n");
+}
+
+void GIFGetBackgroundColor(const struct ColorMapObject* const color_map,
+                           int bgcolor_index, int transparent_index,
+                           uint32_t* const bgcolor) {
+  (void)color_map;
+  (void)bgcolor_index;
+  (void)transparent_index;
+  (void)bgcolor;
+  ErrorGIFNotAvailable();
+}
+
+int GIFReadGraphicsExtension(const GifByteType* const data, int* const duration,
+                             GIFDisposeMethod* const dispose,
+                             int* const transparent_index) {
+  (void)data;
+  (void)duration;
+  (void)dispose;
+  (void)transparent_index;
+  ErrorGIFNotAvailable();
+  return 0;
+}
+
+int GIFReadFrame(struct GifFileType* const gif, int transparent_index,
+                 GIFFrameRect* const gif_rect,
+                 struct WebPPicture* const picture) {
+  (void)gif;
+  (void)transparent_index;
+  (void)gif_rect;
+  (void)picture;
+  ErrorGIFNotAvailable();
+  return 0;
+}
+
+int GIFReadLoopCount(struct GifFileType* const gif, GifByteType** const buf,
+                     int* const loop_count) {
+  (void)gif;
+  (void)buf;
+  (void)loop_count;
+  ErrorGIFNotAvailable();
+  return 0;
+}
+
+int GIFReadMetadata(struct GifFileType* const gif, GifByteType** const buf,
+                    struct WebPData* const metadata) {
+  (void)gif;
+  (void)buf;
+  (void)metadata;
+  ErrorGIFNotAvailable();
+  return 0;
+}
+
+void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,
+                     const struct WebPPicture* const prev_canvas,
+                     struct WebPPicture* const curr_canvas) {
+  (void)dispose;
+  (void)rect;
+  (void)prev_canvas;
+  (void)curr_canvas;
+  ErrorGIFNotAvailable();
+}
+
+void GIFBlendFrames(const struct WebPPicture* const src,
+                    const GIFFrameRect* const rect,
+                    struct WebPPicture* const dst) {
+  (void)src;
+  (void)rect;
+  (void)dst;
+  ErrorGIFNotAvailable();
+}
+
+void GIFDisplayError(const struct GifFileType* const gif, int gif_error) {
+  (void)gif;
+  (void)gif_error;
+  ErrorGIFNotAvailable();
+}
+
+void GIFClearPic(struct WebPPicture* const pic,
+                 const GIFFrameRect* const rect) {
+  (void)pic;
+  (void)rect;
+  ErrorGIFNotAvailable();
+}
+
+void GIFCopyPixels(const struct WebPPicture* const src,
+                   struct WebPPicture* const dst) {
+  (void)src;
+  (void)dst;
+  ErrorGIFNotAvailable();
+}
+
+#endif  // WEBP_HAVE_GIF
+
+// -----------------------------------------------------------------------------

examples/gifdec.h

@@ -0,0 +1,116 @@
+// Copyright 2014 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// GIF decode.
+
+#ifndef WEBP_EXAMPLES_GIFDEC_H_
+#define WEBP_EXAMPLES_GIFDEC_H_
+
+#include <stdio.h>
+#include "webp/types.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#ifdef WEBP_HAVE_GIF
+#include <gif_lib.h>
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// GIFLIB_MAJOR is only defined in libgif >= 4.2.0.
+#if defined(GIFLIB_MAJOR) && defined(GIFLIB_MINOR)
+# define LOCAL_GIF_VERSION ((GIFLIB_MAJOR << 8) | GIFLIB_MINOR)
+# define LOCAL_GIF_PREREQ(maj, min) \
+    (LOCAL_GIF_VERSION >= (((maj) << 8) | (min)))
+#else
+# define LOCAL_GIF_VERSION 0
+# define LOCAL_GIF_PREREQ(maj, min) 0
+#endif
+
+#define GIF_INDEX_INVALID (-1)
+
+typedef enum GIFDisposeMethod {
+  GIF_DISPOSE_NONE,
+  GIF_DISPOSE_BACKGROUND,
+  GIF_DISPOSE_RESTORE_PREVIOUS
+} GIFDisposeMethod;
+
+typedef struct {
+  int x_offset, y_offset, width, height;
+} GIFFrameRect;
+
+struct WebPData;
+struct WebPPicture;
+
+#ifndef WEBP_HAVE_GIF
+struct ColorMapObject;
+struct GifFileType;
+typedef unsigned char GifByteType;
+#endif
+
+// Given the index of background color and transparent color, returns the
+// corresponding background color (in BGRA format) in 'bgcolor'.
+void GIFGetBackgroundColor(const struct ColorMapObject* const color_map,
+                           int bgcolor_index, int transparent_index,
+                           uint32_t* const bgcolor);
+
+// Parses the given graphics extension data to get frame duration (in 1ms
+// units), dispose method and transparent color index.
+// Returns true on success.
+int GIFReadGraphicsExtension(const GifByteType* const buf, int* const duration,
+                             GIFDisposeMethod* const dispose,
+                             int* const transparent_index);
+
+// Reads the next GIF frame from 'gif' into 'picture'. Also, returns the GIF
+// frame dimensions and offsets in 'rect'.
+// Returns true on success.
+int GIFReadFrame(struct GifFileType* const gif, int transparent_index,
+                 GIFFrameRect* const gif_rect,
+                 struct WebPPicture* const picture);
+
+// Parses loop count from the given Netscape extension data.
+int GIFReadLoopCount(struct GifFileType* const gif, GifByteType** const buf,
+                     int* const loop_count);
+
+// Parses the given ICC or XMP extension data and stores it into 'metadata'.
+// Returns true on success.
+int GIFReadMetadata(struct GifFileType* const gif, GifByteType** const buf,
+                    struct WebPData* const metadata);
+
+// Dispose the pixels within 'rect' of 'curr_canvas' based on 'dispose' method
+// and 'prev_canvas'.
+void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,
+                     const struct WebPPicture* const prev_canvas,
+                     struct WebPPicture* const curr_canvas);
+
+// Given 'src' picture and its frame rectangle 'rect', blend it into 'dst'.
+void GIFBlendFrames(const struct WebPPicture* const src,
+                    const GIFFrameRect* const rect,
+                    struct WebPPicture* const dst);
+
+// Prints an error string based on 'gif_error'.
+void GIFDisplayError(const struct GifFileType* const gif, int gif_error);
+
+// In the given 'pic', clear the pixels in 'rect' to transparent color.
+void GIFClearPic(struct WebPPicture* const pic, const GIFFrameRect* const rect);
+
+// Copy pixels from 'src' to 'dst' honoring strides. 'src' and 'dst' are assumed
+// to be already allocated.
+void GIFCopyPixels(const struct WebPPicture* const src,
+                   struct WebPPicture* const dst);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_EXAMPLES_GIFDEC_H_

examples/img2webp.c

@@ -0,0 +1,339 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  generate an animated WebP out of a sequence of images
+//  (PNG, JPEG, ...)
+//
+//  Example usage:
+//     img2webp -o out.webp -q 40 -mixed -duration 40 input??.png
+//
+// Author: skal@google.com (Pascal Massimino)
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "../examples/example_util.h"
+#include "../imageio/image_dec.h"
+#include "../imageio/imageio_util.h"
+#include "./stopwatch.h"
+#include "./unicode.h"
+#include "sharpyuv/sharpyuv.h"
+#include "webp/encode.h"
+#include "webp/mux.h"
+
+//------------------------------------------------------------------------------
+
+static void Help(void) {
+  printf("Usage:\n\n");
+  printf("  img2webp [file_options] [[frame_options] frame_file]...");
+  printf(" [-o webp_file]\n\n");
+
+  printf("File-level options (only used at the start of compression):\n");
+  printf(" -min_size ............ minimize size\n");
+  printf(" -kmax <int> .......... maximum number of frame between key-frames\n"
+         "                        (0=only keyframes)\n");
+  printf(" -kmin <int> .......... minimum number of frame between key-frames\n"
+         "                        (0=disable key-frames altogether)\n");
+  printf(" -mixed ............... use mixed lossy/lossless automatic mode\n");
+  printf(" -near_lossless <int> . use near-lossless image preprocessing\n"
+         "                        (0..100=off), default=100\n");
+  printf(" -sharp_yuv ........... use sharper (and slower) RGB->YUV "
+                                  "conversion\n                        "
+                                  "(lossy only)\n");
+  printf(" -loop <int> .......... loop count (default: 0, = infinite loop)\n");
+  printf(" -v ................... verbose mode\n");
+  printf(" -h ................... this help\n");
+  printf(" -version ............. print version number and exit\n");
+  printf("\n");
+
+  printf("Per-frame options (only used for subsequent images input):\n");
+  printf(" -d <int> ............. frame duration in ms (default: 100)\n");
+  printf(" -lossless  ........... use lossless mode (default)\n");
+  printf(" -lossy ... ........... use lossy mode\n");
+  printf(" -q <float> ........... quality\n");
+  printf(" -m <int> ............. method to use\n");
+
+  printf("\n");
+  printf("example: img2webp -loop 2 in0.png -lossy in1.jpg\n"
+         "                  -d 80 in2.tiff -o out.webp\n");
+  printf("\nNote: if a single file name is passed as the argument, the "
+         "arguments will be\n");
+  printf("tokenized from this file. The file name must not start with "
+         "the character '-'.\n");
+  printf("\nSupported input formats:\n  %s\n",
+         WebPGetEnabledInputFileFormats());
+}
+
+//------------------------------------------------------------------------------
+
+static int ReadImage(const char filename[], WebPPicture* const pic) {
+  const uint8_t* data = NULL;
+  size_t data_size = 0;
+  WebPImageReader reader;
+  int ok;
+#ifdef HAVE_WINCODEC_H
+  // Try to decode the file using WIC falling back to the other readers for
+  // e.g., WebP.
+  ok = ReadPictureWithWIC(filename, pic, 1, NULL);
+  if (ok) return 1;
+#endif
+  if (!ImgIoUtilReadFile(filename, &data, &data_size)) return 0;
+  reader = WebPGuessImageReader(data, data_size);
+  ok = reader(data, data_size, pic, 1, NULL);
+  WebPFree((void*)data);
+  return ok;
+}
+
+static int SetLoopCount(int loop_count, WebPData* const webp_data) {
+  int ok = 1;
+  WebPMuxError err;
+  uint32_t features;
+  WebPMuxAnimParams new_params;
+  WebPMux* const mux = WebPMuxCreate(webp_data, 1);
+  if (mux == NULL) return 0;
+
+  err = WebPMuxGetFeatures(mux, &features);
+  ok = (err == WEBP_MUX_OK);
+  if (!ok || !(features & ANIMATION_FLAG)) goto End;
+
+  err = WebPMuxGetAnimationParams(mux, &new_params);
+  ok = (err == WEBP_MUX_OK);
+  if (ok) {
+    new_params.loop_count = loop_count;
+    err = WebPMuxSetAnimationParams(mux, &new_params);
+    ok = (err == WEBP_MUX_OK);
+  }
+  if (ok) {
+    WebPDataClear(webp_data);
+    err = WebPMuxAssemble(mux, webp_data);
+    ok = (err == WEBP_MUX_OK);
+  }
+
+ End:
+  WebPMuxDelete(mux);
+  if (!ok) {
+    fprintf(stderr, "Error during loop-count setting\n");
+  }
+  return ok;
+}
+
+//------------------------------------------------------------------------------
+
+int main(int argc, const char* argv[]) {
+  const char* output = NULL;
+  WebPAnimEncoder* enc = NULL;
+  int verbose = 0;
+  int pic_num = 0;
+  int duration = 100;
+  int timestamp_ms = 0;
+  int loop_count = 0;
+  int width = 0, height = 0;
+  WebPAnimEncoderOptions anim_config;
+  WebPConfig config;
+  WebPPicture pic;
+  WebPData webp_data;
+  int c;
+  int have_input = 0;
+  CommandLineArguments cmd_args;
+  int ok;
+
+  INIT_WARGV(argc, argv);
+
+  ok = ExUtilInitCommandLineArguments(argc - 1, argv + 1, &cmd_args);
+  if (!ok) FREE_WARGV_AND_RETURN(1);
+
+  argc = cmd_args.argc_;
+  argv = cmd_args.argv_;
+
+  WebPDataInit(&webp_data);
+  if (!WebPAnimEncoderOptionsInit(&anim_config) ||
+      !WebPConfigInit(&config) ||
+      !WebPPictureInit(&pic)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    ok = 0;
+    goto End;
+  }
+
+  // 1st pass of option parsing
+  for (c = 0; ok && c < argc; ++c) {
+    if (argv[c][0] == '-') {
+      int parse_error = 0;
+      if (!strcmp(argv[c], "-o") && c + 1 < argc) {
+        argv[c] = NULL;
+        output = (const char*)GET_WARGV_SHIFTED(argv, ++c);
+      } else if (!strcmp(argv[c], "-kmin") && c + 1 < argc) {
+        argv[c] = NULL;
+        anim_config.kmin = ExUtilGetInt(argv[++c], 0, &parse_error);
+      } else if (!strcmp(argv[c], "-kmax") && c + 1 < argc) {
+        argv[c] = NULL;
+        anim_config.kmax = ExUtilGetInt(argv[++c], 0, &parse_error);
+      } else if (!strcmp(argv[c], "-loop") && c + 1 < argc) {
+        argv[c] = NULL;
+        loop_count = ExUtilGetInt(argv[++c], 0, &parse_error);
+        if (loop_count < 0) {
+          fprintf(stderr, "Invalid non-positive loop-count (%d)\n", loop_count);
+          parse_error = 1;
+        }
+      } else if (!strcmp(argv[c], "-min_size")) {
+        anim_config.minimize_size = 1;
+      } else if (!strcmp(argv[c], "-mixed")) {
+        anim_config.allow_mixed = 1;
+        config.lossless = 0;
+      } else if (!strcmp(argv[c], "-near_lossless") && c + 1 < argc) {
+        argv[c] = NULL;
+        config.near_lossless = ExUtilGetInt(argv[++c], 0, &parse_error);
+      } else if (!strcmp(argv[c], "-sharp_yuv")) {
+        config.use_sharp_yuv = 1;
+      } else if (!strcmp(argv[c], "-v")) {
+        verbose = 1;
+      } else if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+        Help();
+        FREE_WARGV_AND_RETURN(0);
+      } else if (!strcmp(argv[c], "-version")) {
+        const int enc_version = WebPGetEncoderVersion();
+        const int mux_version = WebPGetMuxVersion();
+        const int sharpyuv_version = SharpYuvGetVersion();
+        printf("WebP Encoder version: %d.%d.%d\nWebP Mux version: %d.%d.%d\n",
+               (enc_version >> 16) & 0xff, (enc_version >> 8) & 0xff,
+               enc_version & 0xff, (mux_version >> 16) & 0xff,
+               (mux_version >> 8) & 0xff, mux_version & 0xff);
+        printf("libsharpyuv: %d.%d.%d\n", (sharpyuv_version >> 24) & 0xff,
+               (sharpyuv_version >> 16) & 0xffff, sharpyuv_version & 0xff);
+        goto End;
+      } else {
+        continue;
+      }
+      ok = !parse_error;
+      if (!ok) goto End;
+      argv[c] = NULL;   // mark option as 'parsed' during 1st pass
+    } else {
+      have_input |= 1;
+    }
+  }
+  if (!have_input) {
+    fprintf(stderr, "No input file(s) for generating animation!\n");
+    goto End;
+  }
+
+  // image-reading pass
+  pic_num = 0;
+  config.lossless = 1;
+  for (c = 0; ok && c < argc; ++c) {
+    if (argv[c] == NULL) continue;
+    if (argv[c][0] == '-') {    // parse local options
+      int parse_error = 0;
+      if (!strcmp(argv[c], "-lossy")) {
+        if (!anim_config.allow_mixed) config.lossless = 0;
+      } else if (!strcmp(argv[c], "-lossless")) {
+        if (!anim_config.allow_mixed) config.lossless = 1;
+      } else if (!strcmp(argv[c], "-q") && c + 1 < argc) {
+        config.quality = ExUtilGetFloat(argv[++c], &parse_error);
+      } else if (!strcmp(argv[c], "-m") && c + 1 < argc) {
+        config.method = ExUtilGetInt(argv[++c], 0, &parse_error);
+      } else if (!strcmp(argv[c], "-d") && c + 1 < argc) {
+        duration = ExUtilGetInt(argv[++c], 0, &parse_error);
+        if (duration <= 0) {
+          fprintf(stderr, "Invalid negative duration (%d)\n", duration);
+          parse_error = 1;
+        }
+      } else {
+        parse_error = 1;   // shouldn't be here.
+        fprintf(stderr, "Unknown option [%s]\n", argv[c]);
+      }
+      ok = !parse_error;
+      if (!ok) goto End;
+      continue;
+    }
+
+    if (ok) {
+      ok = WebPValidateConfig(&config);
+      if (!ok) {
+        fprintf(stderr, "Invalid configuration.\n");
+        goto End;
+      }
+    }
+
+    // read next input image
+    pic.use_argb = 1;
+    ok = ReadImage((const char*)GET_WARGV_SHIFTED(argv, c), &pic);
+    if (!ok) goto End;
+
+    if (enc == NULL) {
+      width  = pic.width;
+      height = pic.height;
+      enc = WebPAnimEncoderNew(width, height, &anim_config);
+      ok = (enc != NULL);
+      if (!ok) {
+        fprintf(stderr, "Could not create WebPAnimEncoder object.\n");
+      }
+    }
+
+    if (ok) {
+      ok = (width == pic.width && height == pic.height);
+      if (!ok) {
+        fprintf(stderr, "Frame #%d dimension mismatched! "
+                        "Got %d x %d. Was expecting %d x %d.\n",
+                pic_num, pic.width, pic.height, width, height);
+      }
+    }
+
+    if (ok) {
+      ok = WebPAnimEncoderAdd(enc, &pic, timestamp_ms, &config);
+      if (!ok) {
+        fprintf(stderr, "Error while adding frame #%d\n", pic_num);
+      }
+    }
+    WebPPictureFree(&pic);
+    if (!ok) goto End;
+
+    if (verbose) {
+      WFPRINTF(stderr, "Added frame #%3d at time %4d (file: %s)\n",
+               pic_num, timestamp_ms, GET_WARGV_SHIFTED(argv, c));
+    }
+    timestamp_ms += duration;
+    ++pic_num;
+  }
+
+  // add a last fake frame to signal the last duration
+  ok = ok && WebPAnimEncoderAdd(enc, NULL, timestamp_ms, NULL);
+  ok = ok && WebPAnimEncoderAssemble(enc, &webp_data);
+  if (!ok) {
+    fprintf(stderr, "Error during final animation assembly.\n");
+  }
+
+ End:
+  // free resources
+  WebPAnimEncoderDelete(enc);
+
+  if (ok && loop_count > 0) {  // Re-mux to add loop count.
+    ok = SetLoopCount(loop_count, &webp_data);
+  }
+
+  if (ok) {
+    if (output != NULL) {
+      ok = ImgIoUtilWriteFile(output, webp_data.bytes, webp_data.size);
+      if (ok) WFPRINTF(stderr, "output file: %s     ", (const W_CHAR*)output);
+    } else {
+      fprintf(stderr, "[no output file specified]   ");
+    }
+  }
+
+  if (ok) {
+    fprintf(stderr, "[%d frames, %u bytes].\n",
+            pic_num, (unsigned int)webp_data.size);
+  }
+  WebPDataClear(&webp_data);
+  ExUtilDeleteCommandLineArguments(&cmd_args);
+  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+}

examples/stopwatch.h

@@ -0,0 +1,63 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Helper functions to measure elapsed time.
+//
+// Author: Mikolaj Zalewski (mikolajz@google.com)
+
+#ifndef WEBP_EXAMPLES_STOPWATCH_H_
+#define WEBP_EXAMPLES_STOPWATCH_H_
+
+#include "webp/types.h"
+
+#if defined _WIN32 && !defined __GNUC__
+#include <windows.h>
+
+typedef LARGE_INTEGER Stopwatch;
+
+static WEBP_INLINE void StopwatchReset(Stopwatch* watch) {
+  QueryPerformanceCounter(watch);
+}
+
+static WEBP_INLINE double StopwatchReadAndReset(Stopwatch* watch) {
+  const LARGE_INTEGER old_value = *watch;
+  LARGE_INTEGER freq;
+  if (!QueryPerformanceCounter(watch))
+    return 0.0;
+  if (!QueryPerformanceFrequency(&freq))
+    return 0.0;
+  if (freq.QuadPart == 0)
+    return 0.0;
+  return (watch->QuadPart - old_value.QuadPart) / (double)freq.QuadPart;
+}
+
+
+#else    /* !_WIN32 */
+#include <string.h>  // memcpy
+#include <sys/time.h>
+
+typedef struct timeval Stopwatch;
+
+static WEBP_INLINE void StopwatchReset(Stopwatch* watch) {
+  gettimeofday(watch, NULL);
+}
+
+static WEBP_INLINE double StopwatchReadAndReset(Stopwatch* watch) {
+  struct timeval old_value;
+  double delta_sec, delta_usec;
+  memcpy(&old_value, watch, sizeof(old_value));
+  gettimeofday(watch, NULL);
+  delta_sec = (double)watch->tv_sec - old_value.tv_sec;
+  delta_usec = (double)watch->tv_usec - old_value.tv_usec;
+  return delta_sec + delta_usec / 1000000.0;
+}
+
+#endif   /* _WIN32 */
+
+#endif  // WEBP_EXAMPLES_STOPWATCH_H_

examples/unicode.h

@@ -0,0 +1,116 @@
+// Copyright 2018 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Unicode support for Windows. The main idea is to maintain an array of Unicode
+// arguments (wargv) and use it only for file paths. The regular argv is used
+// for everything else.
+//
+// Author: Yannis Guyon (yguyon@google.com)
+
+#ifndef WEBP_EXAMPLES_UNICODE_H_
+#define WEBP_EXAMPLES_UNICODE_H_
+
+#include <stdio.h>
+
+#if defined(_WIN32) && defined(_UNICODE)
+
+// wchar_t is used instead of TCHAR because we only perform additional work when
+// Unicode is enabled and because the output of CommandLineToArgvW() is wchar_t.
+
+#include <fcntl.h>
+#include <io.h>
+#include <wchar.h>
+#include <windows.h>
+#include <shellapi.h>
+
+// Create a wchar_t array containing Unicode parameters.
+#define INIT_WARGV(ARGC, ARGV)                                                \
+  int wargc;                                                                  \
+  const W_CHAR** const wargv =                                                \
+      (const W_CHAR**)CommandLineToArgvW(GetCommandLineW(), &wargc);          \
+  do {                                                                        \
+    if (wargv == NULL || wargc != (ARGC)) {                                   \
+      fprintf(stderr, "Error: Unable to get Unicode arguments.\n");           \
+      FREE_WARGV_AND_RETURN(-1);                                              \
+    }                                                                         \
+  } while (0)
+
+// Use this to get a Unicode argument (e.g. file path).
+#define GET_WARGV(UNUSED, C) wargv[C]
+// For cases where argv is shifted by one compared to wargv.
+#define GET_WARGV_SHIFTED(UNUSED, C) wargv[(C) + 1]
+#define GET_WARGV_OR_NULL() wargv
+
+// Release resources. LocalFree() is needed after CommandLineToArgvW().
+#define FREE_WARGV() LOCAL_FREE((W_CHAR** const)wargv)
+#define LOCAL_FREE(WARGV)                  \
+  do {                                     \
+    if ((WARGV) != NULL) LocalFree(WARGV); \
+  } while (0)
+
+#define W_CHAR wchar_t  // WCHAR without underscore might already be defined.
+#define TO_W_CHAR(STR) (L##STR)
+
+#define WFOPEN(ARG, OPT) _wfopen((const W_CHAR*)ARG, TO_W_CHAR(OPT))
+
+#define WFPRINTF(STREAM, STR, ...)                    \
+  do {                                                \
+    int prev_mode;                                    \
+    fflush(STREAM);                                   \
+    prev_mode = _setmode(_fileno(STREAM), _O_U8TEXT); \
+    fwprintf(STREAM, TO_W_CHAR(STR), __VA_ARGS__);    \
+    fflush(STREAM);                                   \
+    (void)_setmode(_fileno(STREAM), prev_mode);       \
+  } while (0)
+#define WPRINTF(STR, ...) WFPRINTF(stdout, STR, __VA_ARGS__)
+
+#define WSTRLEN(FILENAME) wcslen((const W_CHAR*)FILENAME)
+#define WSTRCMP(FILENAME, STR) wcscmp((const W_CHAR*)FILENAME, TO_W_CHAR(STR))
+#define WSTRRCHR(FILENAME, STR) wcsrchr((const W_CHAR*)FILENAME, TO_W_CHAR(STR))
+#define WSNPRINTF(A, B, STR, ...) _snwprintf(A, B, TO_W_CHAR(STR), __VA_ARGS__)
+
+#else
+
+#include <string.h>
+
+// Unicode file paths work as is on Unix platforms, and no extra work is done on
+// Windows either if Unicode is disabled.
+
+#define INIT_WARGV(ARGC, ARGV)
+
+#define GET_WARGV(ARGV, C) (ARGV)[C]
+#define GET_WARGV_SHIFTED(ARGV, C) (ARGV)[C]
+#define GET_WARGV_OR_NULL() NULL
+
+#define FREE_WARGV()
+#define LOCAL_FREE(WARGV)
+
+#define W_CHAR char
+#define TO_W_CHAR(STR) (STR)
+
+#define WFOPEN(ARG, OPT) fopen(ARG, OPT)
+
+#define WPRINTF(STR, ...) printf(STR, __VA_ARGS__)
+#define WFPRINTF(STREAM, STR, ...) fprintf(STREAM, STR, __VA_ARGS__)
+
+#define WSTRLEN(FILENAME) strlen(FILENAME)
+#define WSTRCMP(FILENAME, STR) strcmp(FILENAME, STR)
+#define WSTRRCHR(FILENAME, STR) strrchr(FILENAME, STR)
+#define WSNPRINTF(A, B, STR, ...) snprintf(A, B, STR, __VA_ARGS__)
+
+#endif  // defined(_WIN32) && defined(_UNICODE)
+
+// Don't forget to free wargv before returning (e.g. from main).
+#define FREE_WARGV_AND_RETURN(VALUE) \
+  do {                               \
+    FREE_WARGV();                    \
+    return (VALUE);                  \
+  } while (0)
+
+#endif  // WEBP_EXAMPLES_UNICODE_H_

examples/unicode_gif.h

@@ -0,0 +1,76 @@
+// Copyright 2018 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// giflib doesn't have a Unicode DGifOpenFileName(). Let's make one.
+//
+// Author: Yannis Guyon (yguyon@google.com)
+
+#ifndef WEBP_EXAMPLES_UNICODE_GIF_H_
+#define WEBP_EXAMPLES_UNICODE_GIF_H_
+
+#include "./unicode.h"
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"  // For WEBP_HAVE_GIF
+#endif
+
+#if defined(WEBP_HAVE_GIF)
+
+#ifdef _WIN32
+#include <fcntl.h>  // Not standard, needed for _topen and flags.
+#include <io.h>
+#endif
+
+#include <gif_lib.h>
+#include <string.h>
+#include "./gifdec.h"
+
+#if !defined(STDIN_FILENO)
+#define STDIN_FILENO 0
+#endif
+
+static GifFileType* DGifOpenFileUnicode(const W_CHAR* file_name, int* error) {
+  if (!WSTRCMP(file_name, "-")) {
+#if LOCAL_GIF_PREREQ(5, 0)
+    return DGifOpenFileHandle(STDIN_FILENO, error);
+#else
+    (void)error;
+    return DGifOpenFileHandle(STDIN_FILENO);
+#endif
+  }
+
+#if defined(_WIN32) && defined(_UNICODE)
+  {
+    int file_handle = _wopen(file_name, _O_RDONLY | _O_BINARY);
+    if (file_handle == -1) {
+      if (error != NULL) *error = D_GIF_ERR_OPEN_FAILED;
+      return NULL;
+    }
+
+#if LOCAL_GIF_PREREQ(5, 0)
+    return DGifOpenFileHandle(file_handle, error);
+#else
+    return DGifOpenFileHandle(file_handle);
+#endif
+  }
+
+#else
+
+#if LOCAL_GIF_PREREQ(5, 0)
+  return DGifOpenFileName(file_name, error);
+#else
+  return DGifOpenFileName(file_name);
+#endif
+
+#endif  // defined(_WIN32) && defined(_UNICODE)
+  // DGifCloseFile() is called later.
+}
+
+#endif  // defined(WEBP_HAVE_GIF)
+
+#endif  // WEBP_EXAMPLES_UNICODE_GIF_H_

examples/vwebp.c

@@ -0,0 +1,654 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Simple OpenGL-based WebP file viewer.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#if defined(__unix__) || defined(__CYGWIN__)
+#define _POSIX_C_SOURCE 200112L  // for setenv
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if defined(WEBP_HAVE_GL)
+
+#if defined(HAVE_GLUT_GLUT_H)
+#include <GLUT/glut.h>
+#else
+#include <GL/glut.h>
+#ifdef FREEGLUT
+#include <GL/freeglut.h>
+#endif
+#endif
+
+#ifdef WEBP_HAVE_QCMS
+#include <qcms.h>
+#endif
+
+#include "webp/decode.h"
+#include "webp/demux.h"
+
+#include "../examples/example_util.h"
+#include "../imageio/imageio_util.h"
+#include "./unicode.h"
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf
+#endif
+
+// Unfortunate global variables. Gathered into a struct for comfort.
+static struct {
+  int has_animation;
+  int has_color_profile;
+  int done;
+  int decoding_error;
+  int print_info;
+  int only_deltas;
+  int use_color_profile;
+  int draw_anim_background_color;
+
+  int canvas_width, canvas_height;
+  int loop_count;
+  uint32_t bg_color;
+
+  const char* file_name;
+  WebPData data;
+  WebPDecoderConfig config;
+  const WebPDecBuffer* pic;
+  WebPDemuxer* dmux;
+  WebPIterator curr_frame;
+  WebPIterator prev_frame;
+  WebPChunkIterator iccp;
+  int viewport_width, viewport_height;
+} kParams;
+
+static void ClearPreviousPic(void) {
+  WebPFreeDecBuffer((WebPDecBuffer*)kParams.pic);
+  kParams.pic = NULL;
+}
+
+static void ClearParams(void) {
+  ClearPreviousPic();
+  WebPDataClear(&kParams.data);
+  WebPDemuxReleaseIterator(&kParams.curr_frame);
+  WebPDemuxReleaseIterator(&kParams.prev_frame);
+  WebPDemuxReleaseChunkIterator(&kParams.iccp);
+  WebPDemuxDelete(kParams.dmux);
+  kParams.dmux = NULL;
+}
+
+// Sets the previous frame to the dimensions of the canvas and has it dispose
+// to background to cause the canvas to be cleared.
+static void ClearPreviousFrame(void) {
+  WebPIterator* const prev = &kParams.prev_frame;
+  prev->width = kParams.canvas_width;
+  prev->height = kParams.canvas_height;
+  prev->x_offset = prev->y_offset = 0;
+  prev->dispose_method = WEBP_MUX_DISPOSE_BACKGROUND;
+}
+
+// -----------------------------------------------------------------------------
+// Color profile handling
+static int ApplyColorProfile(const WebPData* const profile,
+                             WebPDecBuffer* const rgba) {
+#ifdef WEBP_HAVE_QCMS
+  int i, ok = 0;
+  uint8_t* line;
+  uint8_t major_revision;
+  qcms_profile* input_profile = NULL;
+  qcms_profile* output_profile = NULL;
+  qcms_transform* transform = NULL;
+  const qcms_data_type input_type = QCMS_DATA_RGBA_8;
+  const qcms_data_type output_type = QCMS_DATA_RGBA_8;
+  const qcms_intent intent = QCMS_INTENT_DEFAULT;
+
+  if (profile == NULL || rgba == NULL) return 0;
+  if (profile->bytes == NULL || profile->size < 10) return 1;
+  major_revision = profile->bytes[8];
+
+  qcms_enable_iccv4();
+  input_profile = qcms_profile_from_memory(profile->bytes, profile->size);
+  // qcms_profile_is_bogus() is broken with ICCv4.
+  if (input_profile == NULL ||
+      (major_revision < 4 && qcms_profile_is_bogus(input_profile))) {
+    fprintf(stderr, "Color profile is bogus!\n");
+    goto Error;
+  }
+
+  output_profile = qcms_profile_sRGB();
+  if (output_profile == NULL) {
+    fprintf(stderr, "Error creating output color profile!\n");
+    goto Error;
+  }
+
+  qcms_profile_precache_output_transform(output_profile);
+  transform = qcms_transform_create(input_profile, input_type,
+                                    output_profile, output_type,
+                                    intent);
+  if (transform == NULL) {
+    fprintf(stderr, "Error creating color transform!\n");
+    goto Error;
+  }
+
+  line = rgba->u.RGBA.rgba;
+  for (i = 0; i < rgba->height; ++i, line += rgba->u.RGBA.stride) {
+    qcms_transform_data(transform, line, line, rgba->width);
+  }
+  ok = 1;
+
+ Error:
+  if (input_profile != NULL) qcms_profile_release(input_profile);
+  if (output_profile != NULL) qcms_profile_release(output_profile);
+  if (transform != NULL) qcms_transform_release(transform);
+  return ok;
+#else
+  (void)profile;
+  (void)rgba;
+  return 1;
+#endif  // WEBP_HAVE_QCMS
+}
+
+//------------------------------------------------------------------------------
+// File decoding
+
+static int Decode(void) {   // Fills kParams.curr_frame
+  const WebPIterator* const curr = &kParams.curr_frame;
+  WebPDecoderConfig* const config = &kParams.config;
+  WebPDecBuffer* const output_buffer = &config->output;
+  int ok = 0;
+
+  ClearPreviousPic();
+  output_buffer->colorspace = MODE_RGBA;
+  ok = (WebPDecode(curr->fragment.bytes, curr->fragment.size,
+                   config) == VP8_STATUS_OK);
+  if (!ok) {
+    fprintf(stderr, "Decoding of frame #%d failed!\n", curr->frame_num);
+  } else {
+    kParams.pic = output_buffer;
+    if (kParams.use_color_profile) {
+      ok = ApplyColorProfile(&kParams.iccp.chunk, output_buffer);
+      if (!ok) {
+        fprintf(stderr, "Applying color profile to frame #%d failed!\n",
+                curr->frame_num);
+      }
+    }
+  }
+  return ok;
+}
+
+static void decode_callback(int what) {
+  if (what == 0 && !kParams.done) {
+    int duration = 0;
+    if (kParams.dmux != NULL) {
+      WebPIterator* const curr = &kParams.curr_frame;
+      if (!WebPDemuxNextFrame(curr)) {
+        WebPDemuxReleaseIterator(curr);
+        if (WebPDemuxGetFrame(kParams.dmux, 1, curr)) {
+          --kParams.loop_count;
+          kParams.done = (kParams.loop_count == 0);
+          if (kParams.done) return;
+          ClearPreviousFrame();
+        } else {
+          kParams.decoding_error = 1;
+          kParams.done = 1;
+          return;
+        }
+      }
+      duration = curr->duration;
+      // Behavior copied from Chrome, cf:
+      // https://cs.chromium.org/chromium/src/third_party/WebKit/Source/
+      // platform/graphics/DeferredImageDecoder.cpp?
+      // rcl=b4c33049f096cd283f32be9a58b9a9e768227c26&l=246
+      if (duration <= 10) duration = 100;
+    }
+    if (!Decode()) {
+      kParams.decoding_error = 1;
+      kParams.done = 1;
+    } else {
+      glutPostRedisplay();
+      glutTimerFunc(duration, decode_callback, what);
+    }
+  }
+}
+
+//------------------------------------------------------------------------------
+// Callbacks
+
+static void HandleKey(unsigned char key, int pos_x, int pos_y) {
+  // Note: rescaling the window or toggling some features during an animation
+  // generates visual artifacts. This is not fixed because refreshing the frame
+  // may require rendering the whole animation from start till current frame.
+  (void)pos_x;
+  (void)pos_y;
+  if (key == 'q' || key == 'Q' || key == 27 /* Esc */) {
+#ifdef FREEGLUT
+    glutLeaveMainLoop();
+#else
+    ClearParams();
+    exit(0);
+#endif
+  } else if (key == 'c') {
+    if (kParams.has_color_profile && !kParams.decoding_error) {
+      kParams.use_color_profile = 1 - kParams.use_color_profile;
+
+      if (kParams.has_animation) {
+        // Restart the completed animation to pickup the color profile change.
+        if (kParams.done && kParams.loop_count == 0) {
+          kParams.loop_count =
+              (int)WebPDemuxGetI(kParams.dmux, WEBP_FF_LOOP_COUNT) + 1;
+          kParams.done = 0;
+          // Start the decode loop immediately.
+          glutTimerFunc(0, decode_callback, 0);
+        }
+      } else {
+        Decode();
+        glutPostRedisplay();
+      }
+    }
+  } else if (key == 'b') {
+    kParams.draw_anim_background_color = 1 - kParams.draw_anim_background_color;
+    if (!kParams.has_animation) ClearPreviousFrame();
+    glutPostRedisplay();
+  } else if (key == 'i') {
+    kParams.print_info = 1 - kParams.print_info;
+    if (!kParams.has_animation) ClearPreviousFrame();
+    glutPostRedisplay();
+  } else if (key == 'd') {
+    kParams.only_deltas = 1 - kParams.only_deltas;
+    glutPostRedisplay();
+  }
+}
+
+static void HandleReshape(int width, int height) {
+  // Note: reshape doesn't preserve aspect ratio, and might
+  // be handling larger-than-screen pictures incorrectly.
+  glViewport(0, 0, width, height);
+  glMatrixMode(GL_PROJECTION);
+  glLoadIdentity();
+  glMatrixMode(GL_MODELVIEW);
+  glLoadIdentity();
+  kParams.viewport_width = width;
+  kParams.viewport_height = height;
+  if (!kParams.has_animation) ClearPreviousFrame();
+}
+
+static void PrintString(const char* const text) {
+  void* const font = GLUT_BITMAP_9_BY_15;
+  int i;
+  for (i = 0; text[i]; ++i) {
+    glutBitmapCharacter(font, text[i]);
+  }
+}
+
+static void PrintStringW(const char* const text) {
+#if defined(_WIN32) && defined(_UNICODE)
+  void* const font = GLUT_BITMAP_9_BY_15;
+  const W_CHAR* const wtext = (const W_CHAR*)text;
+  int i;
+  for (i = 0; wtext[i]; ++i) {
+    glutBitmapCharacter(font, wtext[i]);
+  }
+#else
+  PrintString(text);
+#endif
+}
+
+static float GetColorf(uint32_t color, int shift) {
+  return ((color >> shift) & 0xff) / 255.f;
+}
+
+static void DrawCheckerBoard(void) {
+  const int square_size = 8;  // must be a power of 2
+  int x, y;
+  GLint viewport[4];  // x, y, width, height
+
+  glPushMatrix();
+
+  glGetIntegerv(GL_VIEWPORT, viewport);
+  // shift to integer coordinates with (0,0) being top-left.
+  glOrtho(0, viewport[2], viewport[3], 0, -1, 1);
+  for (y = 0; y < viewport[3]; y += square_size) {
+    for (x = 0; x < viewport[2]; x += square_size) {
+      const GLubyte color = 128 + 64 * (!((x + y) & square_size));
+      glColor3ub(color, color, color);
+      glRecti(x, y, x + square_size, y + square_size);
+    }
+  }
+  glPopMatrix();
+}
+
+static void DrawBackground(void) {
+  // Whole window cleared with clear color, checkerboard rendered on top of it.
+  glClear(GL_COLOR_BUFFER_BIT);
+  DrawCheckerBoard();
+
+  // ANIM background color rendered (blend) on top. Default is white for still
+  // images (without ANIM chunk). glClear() can't be used for that (no blend).
+  if (kParams.draw_anim_background_color) {
+    glPushMatrix();
+    glLoadIdentity();
+    glColor4f(GetColorf(kParams.bg_color, 16),  // BGRA from spec
+              GetColorf(kParams.bg_color, 8),
+              GetColorf(kParams.bg_color, 0),
+              GetColorf(kParams.bg_color, 24));
+    glRecti(-1, -1, +1, +1);
+    glPopMatrix();
+  }
+}
+
+// Draw background in a scissored rectangle.
+static void DrawBackgroundScissored(int window_x, int window_y, int frame_w,
+                                    int frame_h) {
+  // Only update the requested area, not the whole canvas.
+  window_x = window_x * kParams.viewport_width / kParams.canvas_width;
+  window_y = window_y * kParams.viewport_height / kParams.canvas_height;
+  frame_w = frame_w * kParams.viewport_width / kParams.canvas_width;
+  frame_h = frame_h * kParams.viewport_height / kParams.canvas_height;
+
+  // glScissor() takes window coordinates (0,0 at bottom left).
+  window_y = kParams.viewport_height - window_y - frame_h;
+
+  glEnable(GL_SCISSOR_TEST);
+  glScissor(window_x, window_y, frame_w, frame_h);
+  DrawBackground();
+  glDisable(GL_SCISSOR_TEST);
+}
+
+static void HandleDisplay(void) {
+  const WebPDecBuffer* const pic = kParams.pic;
+  const WebPIterator* const curr = &kParams.curr_frame;
+  WebPIterator* const prev = &kParams.prev_frame;
+  GLfloat xoff, yoff;
+  if (pic == NULL) return;
+  glPushMatrix();
+  glPixelZoom((GLfloat)(+1. / kParams.canvas_width * kParams.viewport_width),
+              (GLfloat)(-1. / kParams.canvas_height * kParams.viewport_height));
+  xoff = (GLfloat)(2. * curr->x_offset / kParams.canvas_width);
+  yoff = (GLfloat)(2. * curr->y_offset / kParams.canvas_height);
+  glRasterPos2f(-1.f + xoff, 1.f - yoff);
+  glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+  glPixelStorei(GL_UNPACK_ROW_LENGTH, pic->u.RGBA.stride / 4);
+
+  if (kParams.only_deltas) {
+    DrawBackground();
+  } else {
+    // The rectangle of the previous frame might be different than the current
+    // frame, so we may need to DrawBackgroundScissored for both.
+    if (prev->dispose_method == WEBP_MUX_DISPOSE_BACKGROUND) {
+      // Clear the previous frame rectangle.
+      DrawBackgroundScissored(prev->x_offset, prev->y_offset, prev->width,
+                              prev->height);
+    }
+    if (curr->blend_method == WEBP_MUX_NO_BLEND) {
+      // We simulate no-blending behavior by first clearing the current frame
+      // rectangle and then alpha-blending against it.
+      DrawBackgroundScissored(curr->x_offset, curr->y_offset, curr->width,
+                              curr->height);
+    }
+  }
+
+  *prev = *curr;
+
+  glDrawPixels(pic->width, pic->height,
+               GL_RGBA, GL_UNSIGNED_BYTE,
+               (GLvoid*)pic->u.RGBA.rgba);
+  if (kParams.print_info) {
+    char tmp[32];
+
+    glColor4f(0.90f, 0.0f, 0.90f, 1.0f);
+    glRasterPos2f(-0.95f, 0.90f);
+    PrintStringW(kParams.file_name);
+
+    snprintf(tmp, sizeof(tmp), "Dimension:%d x %d", pic->width, pic->height);
+    glColor4f(0.90f, 0.0f, 0.90f, 1.0f);
+    glRasterPos2f(-0.95f, 0.80f);
+    PrintString(tmp);
+    if (curr->x_offset != 0 || curr->y_offset != 0) {
+      snprintf(tmp, sizeof(tmp), " (offset:%d,%d)",
+               curr->x_offset, curr->y_offset);
+      glRasterPos2f(-0.95f, 0.70f);
+      PrintString(tmp);
+    }
+  }
+  glPopMatrix();
+#if defined(__APPLE__) || defined(_WIN32)
+  glFlush();
+#else
+  glutSwapBuffers();
+#endif
+}
+
+static void StartDisplay(void) {
+  int width = kParams.canvas_width;
+  int height = kParams.canvas_height;
+  int screen_width, screen_height;
+  // TODO(webp:365) GLUT_DOUBLE results in flickering / old frames to be
+  // partially displayed with animated webp + alpha.
+#if defined(__APPLE__) || defined(_WIN32)
+  glutInitDisplayMode(GLUT_RGBA);
+#else
+  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
+#endif
+  screen_width = glutGet(GLUT_SCREEN_WIDTH);
+  screen_height = glutGet(GLUT_SCREEN_HEIGHT);
+  if (width > screen_width || height > screen_height) {
+    if (width > screen_width) {
+      height = (height * screen_width + width - 1) / width;
+      width = screen_width;
+    }
+    if (height > screen_height) {
+      width = (width * screen_height + height - 1) / height;
+      height = screen_height;
+    }
+  }
+  glutInitWindowSize(width, height);
+  glutCreateWindow("WebP viewer");
+  glutDisplayFunc(HandleDisplay);
+  glutReshapeFunc(HandleReshape);
+  glutIdleFunc(NULL);
+  glutKeyboardFunc(HandleKey);
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+  glEnable(GL_BLEND);
+  glClearColor(0, 0, 0, 0);  // window will be cleared to black (no blend)
+  DrawBackground();
+}
+
+//------------------------------------------------------------------------------
+// Main
+
+static void Help(void) {
+  printf(
+      "Usage: vwebp in_file [options]\n\n"
+      "Decodes the WebP image file and visualize it using OpenGL\n"
+      "Options are:\n"
+      "  -version ..... print version number and exit\n"
+      "  -noicc ....... don't use the icc profile if present\n"
+      "  -nofancy ..... don't use the fancy YUV420 upscaler\n"
+      "  -nofilter .... disable in-loop filtering\n"
+      "  -dither <int>  dithering strength (0..100), default=50\n"
+      "  -noalphadither disable alpha plane dithering\n"
+      "  -usebgcolor .. display background color\n"
+      "  -mt .......... use multi-threading\n"
+      "  -info ........ print info\n"
+      "  -h ........... this help message\n"
+      "\n"
+      "Keyboard shortcuts:\n"
+      "  'c' ................ toggle use of color profile\n"
+      "  'b' ................ toggle background color display\n"
+      "  'i' ................ overlay file information\n"
+      "  'd' ................ disable blending & disposal (debug)\n"
+      "  'q' / 'Q' / ESC .... quit\n");
+}
+
+int main(int argc, char* argv[]) {
+  int c;
+  WebPDecoderConfig* const config = &kParams.config;
+  WebPIterator* const curr = &kParams.curr_frame;
+
+  INIT_WARGV(argc, argv);
+
+  if (!WebPInitDecoderConfig(config)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    FREE_WARGV_AND_RETURN(-1);
+  }
+  config->options.dithering_strength = 50;
+  config->options.alpha_dithering_strength = 100;
+  kParams.use_color_profile = 1;
+  // Background color hidden by default to see transparent areas.
+  kParams.draw_anim_background_color = 0;
+
+  for (c = 1; c < argc; ++c) {
+    int parse_error = 0;
+    if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+      Help();
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-noicc")) {
+      kParams.use_color_profile = 0;
+    } else if (!strcmp(argv[c], "-nofancy")) {
+      config->options.no_fancy_upsampling = 1;
+    } else if (!strcmp(argv[c], "-nofilter")) {
+      config->options.bypass_filtering = 1;
+    } else if (!strcmp(argv[c], "-noalphadither")) {
+      config->options.alpha_dithering_strength = 0;
+    } else if (!strcmp(argv[c], "-usebgcolor")) {
+      kParams.draw_anim_background_color = 1;
+    } else if (!strcmp(argv[c], "-dither") && c + 1 < argc) {
+      config->options.dithering_strength =
+          ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if (!strcmp(argv[c], "-info")) {
+      kParams.print_info = 1;
+    } else if (!strcmp(argv[c], "-version")) {
+      const int dec_version = WebPGetDecoderVersion();
+      const int dmux_version = WebPGetDemuxVersion();
+      printf("WebP Decoder version: %d.%d.%d\nWebP Demux version: %d.%d.%d\n",
+             (dec_version >> 16) & 0xff, (dec_version >> 8) & 0xff,
+             dec_version & 0xff, (dmux_version >> 16) & 0xff,
+             (dmux_version >> 8) & 0xff, dmux_version & 0xff);
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-mt")) {
+      config->options.use_threads = 1;
+    } else if (!strcmp(argv[c], "--")) {
+      if (c < argc - 1) kParams.file_name = (const char*)GET_WARGV(argv, ++c);
+      break;
+    } else if (argv[c][0] == '-') {
+      printf("Unknown option '%s'\n", argv[c]);
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    } else {
+      kParams.file_name = (const char*)GET_WARGV(argv, c);
+    }
+
+    if (parse_error) {
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    }
+  }
+
+  if (kParams.file_name == NULL) {
+    printf("missing input file!!\n");
+    Help();
+    FREE_WARGV_AND_RETURN(0);
+  }
+
+  if (!ImgIoUtilReadFile(kParams.file_name,
+                         &kParams.data.bytes, &kParams.data.size)) {
+    goto Error;
+  }
+
+  if (!WebPGetInfo(kParams.data.bytes, kParams.data.size, NULL, NULL)) {
+    fprintf(stderr, "Input file doesn't appear to be WebP format.\n");
+    goto Error;
+  }
+
+  kParams.dmux = WebPDemux(&kParams.data);
+  if (kParams.dmux == NULL) {
+    fprintf(stderr, "Could not create demuxing object!\n");
+    goto Error;
+  }
+
+  kParams.canvas_width = WebPDemuxGetI(kParams.dmux, WEBP_FF_CANVAS_WIDTH);
+  kParams.canvas_height = WebPDemuxGetI(kParams.dmux, WEBP_FF_CANVAS_HEIGHT);
+  if (kParams.print_info) {
+    printf("Canvas: %d x %d\n", kParams.canvas_width, kParams.canvas_height);
+  }
+
+  ClearPreviousFrame();
+
+  memset(&kParams.iccp, 0, sizeof(kParams.iccp));
+  kParams.has_color_profile =
+      !!(WebPDemuxGetI(kParams.dmux, WEBP_FF_FORMAT_FLAGS) & ICCP_FLAG);
+  if (kParams.has_color_profile) {
+#ifdef WEBP_HAVE_QCMS
+    if (!WebPDemuxGetChunk(kParams.dmux, "ICCP", 1, &kParams.iccp)) goto Error;
+    printf("VP8X: Found color profile\n");
+#else
+    fprintf(stderr, "Warning: color profile present, but qcms is unavailable!\n"
+            "Build libqcms from Mozilla or Chromium and define WEBP_HAVE_QCMS "
+            "before building.\n");
+#endif
+  }
+
+  if (!WebPDemuxGetFrame(kParams.dmux, 1, curr)) goto Error;
+
+  kParams.has_animation = (curr->num_frames > 1);
+  kParams.loop_count = (int)WebPDemuxGetI(kParams.dmux, WEBP_FF_LOOP_COUNT);
+  kParams.bg_color = WebPDemuxGetI(kParams.dmux, WEBP_FF_BACKGROUND_COLOR);
+  printf("VP8X: Found %d images in file (loop count = %d)\n",
+         curr->num_frames, kParams.loop_count);
+
+  // Decode first frame
+  if (!Decode()) goto Error;
+
+  // Position iterator to last frame. Next call to HandleDisplay will wrap over.
+  // We take this into account by bumping up loop_count.
+  WebPDemuxGetFrame(kParams.dmux, 0, curr);
+  if (kParams.loop_count) ++kParams.loop_count;
+
+#if defined(__unix__) || defined(__CYGWIN__)
+  // Work around GLUT compositor bug.
+  // https://bugs.launchpad.net/ubuntu/+source/freeglut/+bug/369891
+  setenv("XLIB_SKIP_ARGB_VISUALS", "1", 1);
+#endif
+
+  // Start display (and timer)
+  glutInit(&argc, argv);
+#ifdef FREEGLUT
+  glutSetOption(GLUT_ACTION_ON_WINDOW_CLOSE, GLUT_ACTION_CONTINUE_EXECUTION);
+#endif
+  StartDisplay();
+
+  if (kParams.has_animation) glutTimerFunc(0, decode_callback, 0);
+  glutMainLoop();
+
+  // Should only be reached when using FREEGLUT:
+  ClearParams();
+  FREE_WARGV_AND_RETURN(0);
+
+ Error:
+  ClearParams();
+  FREE_WARGV_AND_RETURN(-1);
+}
+
+#else   // !WEBP_HAVE_GL
+
+int main(int argc, const char* argv[]) {
+  fprintf(stderr, "OpenGL support not enabled in %s.\n", argv[0]);
+  (void)argc;
+  return 0;
+}
+
+#endif
+
+//------------------------------------------------------------------------------

extras/Makefile.am

@@ -0,0 +1,44 @@
+AM_CPPFLAGS += -I$(top_builddir) -I$(top_srcdir)
+AM_CPPFLAGS += -I$(top_builddir)/src -I$(top_srcdir)/src
+noinst_LTLIBRARIES = libwebpextras.la
+
+noinst_HEADERS =
+noinst_HEADERS += ../src/webp/types.h
+
+libwebpextras_la_SOURCES =
+libwebpextras_la_SOURCES += extras.c extras.h quality_estimate.c
+
+libwebpextras_la_CPPFLAGS = $(AM_CPPFLAGS)
+libwebpextras_la_LDFLAGS = -lm
+libwebpextras_la_LIBADD = ../src/libwebp.la
+
+noinst_PROGRAMS =
+noinst_PROGRAMS += webp_quality
+if BUILD_DEMUX
+  noinst_PROGRAMS += get_disto
+endif
+if BUILD_VWEBP_SDL
+  noinst_PROGRAMS += vwebp_sdl
+endif
+
+get_disto_SOURCES  = get_disto.c
+get_disto_CPPFLAGS = $(AM_CPPFLAGS)
+get_disto_LDADD =
+get_disto_LDADD += ../imageio/libimageio_util.la
+get_disto_LDADD += ../imageio/libimagedec.la
+get_disto_LDADD += ../src/libwebp.la
+get_disto_LDADD += $(PNG_LIBS) $(JPEG_LIBS) $(TIFF_LIBS)
+
+webp_quality_SOURCES  = webp_quality.c
+webp_quality_CPPFLAGS = $(AM_CPPFLAGS)
+webp_quality_LDADD =
+webp_quality_LDADD += ../imageio/libimageio_util.la
+webp_quality_LDADD += libwebpextras.la
+webp_quality_LDADD += ../src/libwebp.la
+
+vwebp_sdl_SOURCES  = vwebp_sdl.c webp_to_sdl.c webp_to_sdl.h
+vwebp_sdl_CPPFLAGS = $(AM_CPPFLAGS) $(SDL_INCLUDES)
+vwebp_sdl_LDADD =
+vwebp_sdl_LDADD += ../imageio/libimageio_util.la
+vwebp_sdl_LDADD += ../src/libwebp.la
+vwebp_sdl_LDADD += $(SDL_LIBS)

extras/extras.c

@@ -0,0 +1,162 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Additional WebP utilities.
+//
+
+#include "extras/extras.h"
+#include "webp/format_constants.h"
+#include "src/dsp/dsp.h"
+
+#include <assert.h>
+#include <string.h>
+
+#define XTRA_MAJ_VERSION 1
+#define XTRA_MIN_VERSION 3
+#define XTRA_REV_VERSION 1
+
+//------------------------------------------------------------------------------
+
+int WebPGetExtrasVersion(void) {
+  return (XTRA_MAJ_VERSION << 16) | (XTRA_MIN_VERSION << 8) | XTRA_REV_VERSION;
+}
+
+//------------------------------------------------------------------------------
+
+int WebPImportGray(const uint8_t* gray_data, WebPPicture* pic) {
+  int y, width, uv_width;
+  if (pic == NULL || gray_data == NULL) return 0;
+  pic->colorspace = WEBP_YUV420;
+  if (!WebPPictureAlloc(pic)) return 0;
+  width = pic->width;
+  uv_width = (width + 1) >> 1;
+  for (y = 0; y < pic->height; ++y) {
+    memcpy(pic->y + y * pic->y_stride, gray_data, width);
+    gray_data += width;    // <- we could use some 'data_stride' here if needed
+    if ((y & 1) == 0) {
+      memset(pic->u + (y >> 1) * pic->uv_stride, 128, uv_width);
+      memset(pic->v + (y >> 1) * pic->uv_stride, 128, uv_width);
+    }
+  }
+  return 1;
+}
+
+int WebPImportRGB565(const uint8_t* rgb565, WebPPicture* pic) {
+  int x, y;
+  uint32_t* dst;
+  if (pic == NULL || rgb565 == NULL) return 0;
+  pic->colorspace = WEBP_YUV420;
+  pic->use_argb = 1;
+  if (!WebPPictureAlloc(pic)) return 0;
+  dst = pic->argb;
+  for (y = 0; y < pic->height; ++y) {
+    const int width = pic->width;
+    for (x = 0; x < width; ++x) {
+#if defined(WEBP_SWAP_16BIT_CSP) && (WEBP_SWAP_16BIT_CSP == 1)
+      const uint32_t rg = rgb565[2 * x + 1];
+      const uint32_t gb = rgb565[2 * x + 0];
+#else
+      const uint32_t rg = rgb565[2 * x + 0];
+      const uint32_t gb = rgb565[2 * x + 1];
+#endif
+      uint32_t r = rg & 0xf8;
+      uint32_t g = ((rg << 5) | (gb >> 3)) & 0xfc;
+      uint32_t b = (gb << 5);
+      // dithering
+      r = r | (r >> 5);
+      g = g | (g >> 6);
+      b = b | (b >> 5);
+      dst[x] = (0xffu << 24) | (r << 16) | (g << 8) | b;
+    }
+    rgb565 += 2 * width;
+    dst += pic->argb_stride;
+  }
+  return 1;
+}
+
+int WebPImportRGB4444(const uint8_t* rgb4444, WebPPicture* pic) {
+  int x, y;
+  uint32_t* dst;
+  if (pic == NULL || rgb4444 == NULL) return 0;
+  pic->colorspace = WEBP_YUV420;
+  pic->use_argb = 1;
+  if (!WebPPictureAlloc(pic)) return 0;
+  dst = pic->argb;
+  for (y = 0; y < pic->height; ++y) {
+    const int width = pic->width;
+    for (x = 0; x < width; ++x) {
+#if defined(WEBP_SWAP_16BIT_CSP) && (WEBP_SWAP_16BIT_CSP == 1)
+      const uint32_t rg = rgb4444[2 * x + 1];
+      const uint32_t ba = rgb4444[2 * x + 0];
+#else
+      const uint32_t rg = rgb4444[2 * x + 0];
+      const uint32_t ba = rgb4444[2 * x + 1];
+#endif
+      uint32_t r = rg & 0xf0;
+      uint32_t g = (rg << 4);
+      uint32_t b = (ba & 0xf0);
+      uint32_t a = (ba << 4);
+      // dithering
+      r = r | (r >> 4);
+      g = g | (g >> 4);
+      b = b | (b >> 4);
+      a = a | (a >> 4);
+      dst[x] = (a << 24) | (r << 16) | (g << 8) | b;
+    }
+    rgb4444 += 2 * width;
+    dst += pic->argb_stride;
+  }
+  return 1;
+}
+
+int WebPImportColorMappedARGB(const uint8_t* indexed, int indexed_stride,
+                              const uint32_t palette[], int palette_size,
+                              WebPPicture* pic) {
+  int x, y;
+  uint32_t* dst;
+  // 256 as the input buffer is uint8_t.
+  assert(MAX_PALETTE_SIZE <= 256);
+  if (pic == NULL || indexed == NULL || indexed_stride < pic->width ||
+      palette == NULL || palette_size > MAX_PALETTE_SIZE || palette_size <= 0) {
+    return 0;
+  }
+  pic->use_argb = 1;
+  if (!WebPPictureAlloc(pic)) return 0;
+  dst = pic->argb;
+  for (y = 0; y < pic->height; ++y) {
+    for (x = 0; x < pic->width; ++x) {
+      // Make sure we are within the palette.
+      if (indexed[x] >= palette_size) {
+        WebPPictureFree(pic);
+        return 0;
+      }
+      dst[x] = palette[indexed[x]];
+    }
+    indexed += indexed_stride;
+    dst += pic->argb_stride;
+  }
+  return 1;
+}
+
+//------------------------------------------------------------------------------
+
+int WebPUnmultiplyARGB(WebPPicture* pic) {
+  int y;
+  uint32_t* dst;
+  if (pic == NULL || pic->use_argb != 1 || pic->argb == NULL) return 0;
+  WebPInitAlphaProcessing();
+  dst = pic->argb;
+  for (y = 0; y < pic->height; ++y) {
+    WebPMultARGBRow(dst, pic->width, /*inverse=*/1);
+    dst += pic->argb_stride;
+  }
+  return 1;
+}
+
+//------------------------------------------------------------------------------

extras/extras.h

@@ -0,0 +1,77 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+
+#ifndef WEBP_EXTRAS_EXTRAS_H_
+#define WEBP_EXTRAS_EXTRAS_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "webp/encode.h"
+
+#define WEBP_EXTRAS_ABI_VERSION 0x0002    // MAJOR(8b) + MINOR(8b)
+
+//------------------------------------------------------------------------------
+
+// Returns the version number of the extras library, packed in hexadecimal using
+// 8bits for each of major/minor/revision. E.g: v2.5.7 is 0x020507.
+WEBP_EXTERN int WebPGetExtrasVersion(void);
+
+//------------------------------------------------------------------------------
+// Ad-hoc colorspace importers.
+
+// Import luma sample (gray scale image) into 'picture'. The 'picture'
+// width and height must be set prior to calling this function.
+WEBP_EXTERN int WebPImportGray(const uint8_t* gray, WebPPicture* picture);
+
+// Import rgb sample in RGB565 packed format into 'picture'. The 'picture'
+// width and height must be set prior to calling this function.
+WEBP_EXTERN int WebPImportRGB565(const uint8_t* rgb565, WebPPicture* pic);
+
+// Import rgb sample in RGB4444 packed format into 'picture'. The 'picture'
+// width and height must be set prior to calling this function.
+WEBP_EXTERN int WebPImportRGB4444(const uint8_t* rgb4444, WebPPicture* pic);
+
+// Import a color mapped image. The number of colors is less or equal to
+// MAX_PALETTE_SIZE. 'pic' must have been initialized. Its content, if any,
+// will be discarded. Returns 'false' in case of error, or if indexed[] contains
+// invalid indices.
+WEBP_EXTERN int
+WebPImportColorMappedARGB(const uint8_t* indexed, int indexed_stride,
+                          const uint32_t palette[], int palette_size,
+                          WebPPicture* pic);
+
+// Convert the ARGB content of 'pic' from associated to unassociated.
+// 'pic' can be for instance the result of calling of some WebPPictureImportXXX
+// functions, with pic->use_argb set to 'true'. It is assumed (and not checked)
+// that the pre-multiplied r/g/b values as less or equal than the alpha value.
+// Return false in case of error (invalid parameter, ...).
+WEBP_EXTERN int WebPUnmultiplyARGB(WebPPicture* pic);
+
+//------------------------------------------------------------------------------
+
+// Parse a bitstream, search for VP8 (lossy) header and report a
+// rough estimation of the quality factor used for compressing the bitstream.
+// If the bitstream is in lossless format, the special value '101' is returned.
+// Otherwise (lossy bitstream), the returned value is in the range [0..100].
+// Any error (invalid bitstream, animated WebP, incomplete header, etc.)
+// will return a value of -1.
+WEBP_EXTERN int VP8EstimateQuality(const uint8_t* const data, size_t size);
+
+//------------------------------------------------------------------------------
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_EXTRAS_EXTRAS_H_

extras/get_disto.c

@@ -0,0 +1,356 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Simple tool to load two webp/png/jpg/tiff files and compute PSNR/SSIM.
+// This is mostly a wrapper around WebPPictureDistortion().
+//
+/*
+ gcc -o get_disto get_disto.c -O3 -I../ -L../examples -L../imageio \
+    -lexample_util -limageio_util -limagedec -lwebp -L/opt/local/lib \
+    -lpng -lz -ljpeg -ltiff -lm -lpthread
+*/
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/encode.h"
+#include "imageio/image_dec.h"
+#include "imageio/imageio_util.h"
+#include "../examples/unicode.h"
+
+static size_t ReadPicture(const char* const filename, WebPPicture* const pic,
+                          int keep_alpha) {
+  const uint8_t* data = NULL;
+  size_t data_size = 0;
+  WebPImageReader reader = NULL;
+  int ok = ImgIoUtilReadFile(filename, &data, &data_size);
+  if (!ok) goto End;
+
+  pic->use_argb = 1;  // force ARGB
+
+#ifdef HAVE_WINCODEC_H
+  // Try to decode the file using WIC falling back to the other readers for
+  // e.g., WebP.
+  ok = ReadPictureWithWIC(filename, pic, keep_alpha, NULL);
+  if (ok) goto End;
+#endif
+  reader = WebPGuessImageReader(data, data_size);
+  ok = reader(data, data_size, pic, keep_alpha, NULL);
+
+ End:
+  if (!ok) {
+    WFPRINTF(stderr, "Error! Could not process file %s\n",
+             (const W_CHAR*)filename);
+  }
+  free((void*)data);
+  return ok ? data_size : 0;
+}
+
+static void RescalePlane(uint8_t* plane, int width, int height,
+                         int x_stride, int y_stride, int max) {
+  const uint32_t factor = (max > 0) ? (255u << 16) / max : 0;
+  int x, y;
+  for (y = 0; y < height; ++y) {
+    uint8_t* const ptr = plane + y * y_stride;
+    for (x = 0; x < width * x_stride; x += x_stride) {
+      const uint32_t diff = (ptr[x] * factor + (1 << 15)) >> 16;
+      ptr[x] = diff;
+    }
+  }
+}
+
+// Return the max absolute difference.
+static int DiffScaleChannel(uint8_t* src1, int stride1,
+                            const uint8_t* src2, int stride2,
+                            int x_stride, int w, int h, int do_scaling) {
+  int x, y;
+  int max = 0;
+  for (y = 0; y < h; ++y) {
+    uint8_t* const ptr1 = src1 + y * stride1;
+    const uint8_t* const ptr2 = src2 + y * stride2;
+    for (x = 0; x < w * x_stride; x += x_stride) {
+      const int diff = abs(ptr1[x] - ptr2[x]);
+      if (diff > max) max = diff;
+      ptr1[x] = diff;
+    }
+  }
+
+  if (do_scaling) RescalePlane(src1, w, h, x_stride, stride1, max);
+  return max;
+}
+
+//------------------------------------------------------------------------------
+// SSIM calculation. We re-implement these functions here, out of dsp/, to avoid
+// breaking the library's hidden visibility. This code duplication avoids the
+// bigger annoyance of having to open up internal details of libdsp...
+
+#define SSIM_KERNEL 3   // total size of the kernel: 2 * SSIM_KERNEL + 1
+
+// struct for accumulating statistical moments
+typedef struct {
+  uint32_t w;              // sum(w_i) : sum of weights
+  uint32_t xm, ym;         // sum(w_i * x_i), sum(w_i * y_i)
+  uint32_t xxm, xym, yym;  // sum(w_i * x_i * x_i), etc.
+} DistoStats;
+
+// hat-shaped filter. Sum of coefficients is equal to 16.
+static const uint32_t kWeight[2 * SSIM_KERNEL + 1] = { 1, 2, 3, 4, 3, 2, 1 };
+
+static WEBP_INLINE double SSIMCalculation(const DistoStats* const stats) {
+  const uint32_t N = stats->w;
+  const uint32_t w2 =  N * N;
+  const uint32_t C1 = 20 * w2;
+  const uint32_t C2 = 60 * w2;
+  const uint32_t C3 = 8 * 8 * w2;   // 'dark' limit ~= 6
+  const uint64_t xmxm = (uint64_t)stats->xm * stats->xm;
+  const uint64_t ymym = (uint64_t)stats->ym * stats->ym;
+  if (xmxm + ymym >= C3) {
+    const int64_t xmym = (int64_t)stats->xm * stats->ym;
+    const int64_t sxy = (int64_t)stats->xym * N - xmym;    // can be negative
+    const uint64_t sxx = (uint64_t)stats->xxm * N - xmxm;
+    const uint64_t syy = (uint64_t)stats->yym * N - ymym;
+    // we descale by 8 to prevent overflow during the fnum/fden multiply.
+    const uint64_t num_S = (2 * (uint64_t)(sxy < 0 ? 0 : sxy) + C2) >> 8;
+    const uint64_t den_S = (sxx + syy + C2) >> 8;
+    const uint64_t fnum = (2 * xmym + C1) * num_S;
+    const uint64_t fden = (xmxm + ymym + C1) * den_S;
+    const double r = (double)fnum / fden;
+    assert(r >= 0. && r <= 1.0);
+    return r;
+  }
+  return 1.;   // area is too dark to contribute meaningfully
+}
+
+static double SSIMGetClipped(const uint8_t* src1, int stride1,
+                             const uint8_t* src2, int stride2,
+                             int xo, int yo, int W, int H) {
+  DistoStats stats = { 0, 0, 0, 0, 0, 0 };
+  const int ymin = (yo - SSIM_KERNEL < 0) ? 0 : yo - SSIM_KERNEL;
+  const int ymax = (yo + SSIM_KERNEL > H - 1) ? H - 1 : yo + SSIM_KERNEL;
+  const int xmin = (xo - SSIM_KERNEL < 0) ? 0 : xo - SSIM_KERNEL;
+  const int xmax = (xo + SSIM_KERNEL > W - 1) ? W - 1 : xo + SSIM_KERNEL;
+  int x, y;
+  src1 += ymin * stride1;
+  src2 += ymin * stride2;
+  for (y = ymin; y <= ymax; ++y, src1 += stride1, src2 += stride2) {
+    for (x = xmin; x <= xmax; ++x) {
+      const uint32_t w = kWeight[SSIM_KERNEL + x - xo]
+                       * kWeight[SSIM_KERNEL + y - yo];
+      const uint32_t s1 = src1[x];
+      const uint32_t s2 = src2[x];
+      stats.w   += w;
+      stats.xm  += w * s1;
+      stats.ym  += w * s2;
+      stats.xxm += w * s1 * s1;
+      stats.xym += w * s1 * s2;
+      stats.yym += w * s2 * s2;
+    }
+  }
+  return SSIMCalculation(&stats);
+}
+
+// Compute SSIM-score map. Return -1 in case of error, max diff otherwise.
+static int SSIMScaleChannel(uint8_t* src1, int stride1,
+                            const uint8_t* src2, int stride2,
+                            int x_stride, int w, int h, int do_scaling) {
+  int x, y;
+  int max = 0;
+  uint8_t* const plane1 = (uint8_t*)malloc(2 * w * h * sizeof(*plane1));
+  uint8_t* const plane2 = plane1 + w * h;
+  if (plane1 == NULL) return -1;
+
+  // extract plane
+  for (y = 0; y < h; ++y) {
+    for (x = 0; x < w; ++x) {
+      plane1[x + y * w] = src1[x * x_stride + y * stride1];
+      plane2[x + y * w] = src2[x * x_stride + y * stride2];
+    }
+  }
+  for (y = 0; y < h; ++y) {
+    for (x = 0; x < w; ++x) {
+      const double ssim = SSIMGetClipped(plane1, w, plane2, w, x, y, w, h);
+      int diff = (int)(255 * (1. - ssim));
+      if (diff < 0) {
+        diff = 0;
+      } else if (diff > max) {
+        max = diff;
+      }
+      src1[x * x_stride + y * stride1] = (diff > 255) ? 255u : (uint8_t)diff;
+    }
+  }
+  free(plane1);
+
+  if (do_scaling) RescalePlane(src1, w, h, x_stride, stride1, max);
+  return max;
+}
+
+// Convert an argb picture to luminance.
+static void ConvertToGray(WebPPicture* const pic) {
+  int x, y;
+  assert(pic != NULL);
+  assert(pic->use_argb);
+  for (y = 0; y < pic->height; ++y) {
+    uint32_t* const row = &pic->argb[y * pic->argb_stride];
+    for (x = 0; x < pic->width; ++x) {
+      const uint32_t argb = row[x];
+      const uint32_t r = (argb >> 16) & 0xff;
+      const uint32_t g = (argb >>  8) & 0xff;
+      const uint32_t b = (argb >>  0) & 0xff;
+      // We use BT.709 for converting to luminance.
+      const uint32_t Y = (uint32_t)(0.2126 * r + 0.7152 * g + 0.0722 * b + .5);
+      row[x] = (argb & 0xff000000u) | (Y * 0x010101u);
+    }
+  }
+}
+
+static void Help(void) {
+  fprintf(stderr,
+          "Usage: get_disto [-ssim][-psnr][-alpha] compressed.webp orig.webp\n"
+          "  -ssim ..... print SSIM distortion\n"
+          "  -psnr ..... print PSNR distortion (default)\n"
+          "  -alpha .... preserve alpha plane\n"
+          "  -h ........ this message\n"
+          "  -o <file> . save the diff map as a WebP lossless file\n"
+          "  -scale .... scale the difference map to fit [0..255] range\n"
+          "  -gray ..... use grayscale for difference map (-scale)\n"
+          "\nSupported input formats:\n  %s\n",
+          WebPGetEnabledInputFileFormats());
+}
+
+int main(int argc, const char* argv[]) {
+  WebPPicture pic1, pic2;
+  size_t size1 = 0, size2 = 0;
+  int ret = 1;
+  float disto[5];
+  int type = 0;
+  int c;
+  int help = 0;
+  int keep_alpha = 0;
+  int scale = 0;
+  int use_gray = 0;
+  const char* name1 = NULL;
+  const char* name2 = NULL;
+  const char* output = NULL;
+
+  INIT_WARGV(argc, argv);
+
+  if (!WebPPictureInit(&pic1) || !WebPPictureInit(&pic2)) {
+    fprintf(stderr, "Can't init pictures\n");
+    FREE_WARGV_AND_RETURN(1);
+  }
+
+  for (c = 1; c < argc; ++c) {
+    if (!strcmp(argv[c], "-ssim")) {
+      type = 1;
+    } else if (!strcmp(argv[c], "-psnr")) {
+      type = 0;
+    } else if (!strcmp(argv[c], "-alpha")) {
+      keep_alpha = 1;
+    } else if (!strcmp(argv[c], "-scale")) {
+      scale = 1;
+    } else if (!strcmp(argv[c], "-gray")) {
+      use_gray = 1;
+    } else if (!strcmp(argv[c], "-h")) {
+      help = 1;
+      ret = 0;
+    } else if (!strcmp(argv[c], "-o")) {
+      if (++c == argc) {
+        fprintf(stderr, "missing file name after %s option.\n", argv[c - 1]);
+        goto End;
+      }
+      output = (const char*)GET_WARGV(argv, c);
+    } else if (name1 == NULL) {
+      name1 = (const char*)GET_WARGV(argv, c);
+    } else {
+      name2 = (const char*)GET_WARGV(argv, c);
+    }
+  }
+  if (help || name1 == NULL || name2 == NULL) {
+    if (!help) {
+      fprintf(stderr, "Error: missing arguments.\n");
+    }
+    Help();
+    goto End;
+  }
+  size1 = ReadPicture(name1, &pic1, 1);
+  size2 = ReadPicture(name2, &pic2, 1);
+  if (size1 == 0 || size2 == 0) goto End;
+
+  if (!keep_alpha) {
+    WebPBlendAlpha(&pic1, 0x00000000);
+    WebPBlendAlpha(&pic2, 0x00000000);
+  }
+
+  if (!WebPPictureDistortion(&pic1, &pic2, type, disto)) {
+    fprintf(stderr, "Error while computing the distortion.\n");
+    goto End;
+  }
+  printf("%u %.2f    %.2f %.2f %.2f %.2f [ %.2f bpp ]\n",
+         (unsigned int)size1,
+         disto[4], disto[0], disto[1], disto[2], disto[3],
+         8.f * size1 / pic1.width / pic1.height);
+
+  if (output != NULL) {
+    uint8_t* data = NULL;
+    size_t data_size = 0;
+    if (pic1.use_argb != pic2.use_argb) {
+      fprintf(stderr, "Pictures are not in the same argb format. "
+                      "Can't save the difference map.\n");
+      goto End;
+    }
+    if (pic1.use_argb) {
+      int n;
+      fprintf(stderr, "max differences per channel: ");
+      for (n = 0; n < 3; ++n) {    // skip the alpha channel
+        const int range = (type == 1) ?
+          SSIMScaleChannel((uint8_t*)pic1.argb + n, pic1.argb_stride * 4,
+                           (const uint8_t*)pic2.argb + n, pic2.argb_stride * 4,
+                           4, pic1.width, pic1.height, scale) :
+          DiffScaleChannel((uint8_t*)pic1.argb + n, pic1.argb_stride * 4,
+                           (const uint8_t*)pic2.argb + n, pic2.argb_stride * 4,
+                           4, pic1.width, pic1.height, scale);
+        if (range < 0) fprintf(stderr, "\nError computing diff map\n");
+        fprintf(stderr, "[%d]", range);
+      }
+      fprintf(stderr, "\n");
+      if (use_gray) ConvertToGray(&pic1);
+    } else {
+      fprintf(stderr, "Can only compute the difference map in ARGB format.\n");
+      goto End;
+    }
+#if !defined(WEBP_REDUCE_CSP)
+    data_size = WebPEncodeLosslessBGRA((const uint8_t*)pic1.argb,
+                                       pic1.width, pic1.height,
+                                       pic1.argb_stride * 4,
+                                       &data);
+    if (data_size == 0) {
+      fprintf(stderr, "Error during lossless encoding.\n");
+      goto End;
+    }
+    ret = ImgIoUtilWriteFile(output, data, data_size) ? 0 : 1;
+    WebPFree(data);
+    if (ret) goto End;
+#else
+    (void)data;
+    (void)data_size;
+    fprintf(stderr, "Cannot save the difference map. Please recompile "
+                    "without the WEBP_REDUCE_CSP flag.\n");
+#endif  // WEBP_REDUCE_CSP
+  }
+  ret = 0;
+
+ End:
+  WebPPictureFree(&pic1);
+  WebPPictureFree(&pic2);
+  FREE_WARGV_AND_RETURN(ret);
+}

extras/quality_estimate.c

@@ -0,0 +1,129 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  VP8EstimateQuality(): rough encoding quality estimate
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "extras/extras.h"
+#include "webp/decode.h"
+
+#include <math.h>
+
+//------------------------------------------------------------------------------
+
+#define INVALID_BIT_POS (1ull << 63)
+
+// In most cases, we don't need to use a full arithmetic decoder, since
+// all the header's bits are written using a uniform probability of 128.
+// We can just parse the header as if it was bits (works in 99.999% cases).
+static WEBP_INLINE uint32_t GetBit(const uint8_t* const data, size_t nb,
+                                   uint64_t max_size, uint64_t* const bit_pos) {
+  uint32_t val = 0;
+  if (*bit_pos + nb <= 8 * max_size) {
+    while (nb-- > 0) {
+      const uint64_t p = (*bit_pos)++;
+      const int bit = !!(data[p >> 3] & (128 >> ((p & 7))));
+      val = (val << 1) | bit;
+    }
+  } else {
+    *bit_pos = INVALID_BIT_POS;
+  }
+  return val;
+}
+
+#define GET_BIT(n) GetBit(data, (n), size, &bit_pos)
+#define CONDITIONAL_SKIP(n) (GET_BIT(1) ? GET_BIT((n)) : 0)
+
+int VP8EstimateQuality(const uint8_t* const data, size_t size) {
+  size_t pos = 0;
+  uint64_t bit_pos;
+  uint64_t sig = 0x00;
+  int ok = 0;
+  int Q = -1;
+  WebPBitstreamFeatures features;
+
+  if (data == NULL) return -1;
+
+  if (WebPGetFeatures(data, size, &features) != VP8_STATUS_OK) {
+    return -1;   // invalid file
+  }
+  if (features.format == 2) return 101;  // lossless
+  if (features.format == 0 || features.has_animation) return -1;   // mixed
+
+  while (pos < size) {
+    sig = (sig >> 8) | ((uint64_t)data[pos++] << 40);
+    if ((sig >> 24) == 0x2a019dull) {
+      ok = 1;
+      break;
+    }
+  }
+  if (!ok) return -1;
+  if (pos + 4 > size) return -1;
+
+  // Skip main Header
+  // width  = (data[pos + 0] | (data[pos + 1] << 8)) & 0x3fff;
+  // height = (data[pos + 2] | (data[pos + 3] << 8)) & 0x3fff;
+  pos += 4;
+  bit_pos = pos * 8;
+
+  GET_BIT(2);  // colorspace + clamp type
+
+  // Segment header
+  if (GET_BIT(1)) {       // use_segment_
+    int s;
+    const int update_map = GET_BIT(1);
+    if (GET_BIT(1)) {     // update data
+      const int absolute_delta = GET_BIT(1);
+      int q[4]  = { 0, 0, 0, 0 };
+      for (s = 0; s < 4; ++s) {
+        if (GET_BIT(1)) {
+          q[s] = GET_BIT(7);
+          if (GET_BIT(1)) q[s] = -q[s];   // sign
+        }
+      }
+      if (absolute_delta) Q = q[0];  // just use the first segment's quantizer
+      for (s = 0; s < 4; ++s) CONDITIONAL_SKIP(7);   //  filter strength
+    }
+    if (update_map) {
+      for (s = 0; s < 3; ++s) CONDITIONAL_SKIP(8);
+    }
+  }
+  // Filter header
+  GET_BIT(1 + 6 + 3);     // simple + level + sharpness
+  if (GET_BIT(1)) {       // use_lf_delta
+    if (GET_BIT(1)) {     // update lf_delta?
+      int n;
+      for (n = 0; n < 4 + 4; ++n) CONDITIONAL_SKIP(6);
+    }
+  }
+  // num partitions
+  GET_BIT(2);
+
+  // ParseQuant
+  {
+    const int base_q = GET_BIT(7);
+    /* dqy1_dc = */ CONDITIONAL_SKIP(5);
+    /* dqy2_dc = */ CONDITIONAL_SKIP(5);
+    /* dqy2_ac = */ CONDITIONAL_SKIP(5);
+    /* dquv_dc = */ CONDITIONAL_SKIP(5);
+    /* dquv_ac = */ CONDITIONAL_SKIP(5);
+
+    if (Q < 0) Q = base_q;
+  }
+  if (bit_pos == INVALID_BIT_POS) return -1;
+
+  // base mapping
+  Q = (127 - Q) * 100 / 127;
+  // correction for power-law behavior in low range
+  if (Q < 80) {
+    Q = (int)(pow(Q / 80., 1. / 0.38) * 80);
+  }
+  return Q;
+}

extras/vwebp_sdl.c

@@ -0,0 +1,101 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Simple SDL-based WebP file viewer.
+// Does not support animation, just static images.
+//
+// Press 'q' to exit.
+//
+// Author: James Zern (jzern@google.com)
+
+#include <stdio.h>
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#if defined(WEBP_HAVE_SDL)
+
+#include "webp_to_sdl.h"
+#include "webp/decode.h"
+#include "imageio/imageio_util.h"
+#include "../examples/unicode.h"
+
+#if defined(WEBP_HAVE_JUST_SDL_H)
+#include <SDL.h>
+#else
+#include <SDL/SDL.h>
+#endif
+
+static void ProcessEvents(void) {
+  int done = 0;
+  SDL_Event event;
+  while (!done && SDL_WaitEvent(&event)) {
+    switch (event.type) {
+      case SDL_KEYUP:
+        switch (event.key.keysym.sym) {
+          case SDLK_q: done = 1; break;
+          default: break;
+        }
+        break;
+      default: break;
+    }
+  }
+}
+
+int main(int argc, char* argv[]) {
+  int c;
+  int ok = 0;
+
+  INIT_WARGV(argc, argv);
+
+  for (c = 1; c < argc; ++c) {
+    const char* file = NULL;
+    const uint8_t* webp = NULL;
+    size_t webp_size = 0;
+    if (!strcmp(argv[c], "-h")) {
+      printf("Usage: %s [-h] image.webp [more_files.webp...]\n", argv[0]);
+      FREE_WARGV_AND_RETURN(0);
+    } else {
+      file = (const char*)GET_WARGV(argv, c);
+    }
+    if (file == NULL) continue;
+    if (!ImgIoUtilReadFile(file, &webp, &webp_size)) {
+      WFPRINTF(stderr, "Error opening file: %s\n", (const W_CHAR*)file);
+      goto Error;
+    }
+    if (webp_size != (size_t)(int)webp_size) {
+      free((void*)webp);
+      fprintf(stderr, "File too large.\n");
+      goto Error;
+    }
+    ok = WebPToSDL((const char*)webp, (int)webp_size);
+    free((void*)webp);
+    if (!ok) {
+      WFPRINTF(stderr, "Error decoding file %s\n", (const W_CHAR*)file);
+      goto Error;
+    }
+    ProcessEvents();
+  }
+  ok = 1;
+
+ Error:
+  SDL_Quit();
+  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+}
+
+#else  // !WEBP_HAVE_SDL
+
+int main(int argc, const char* argv[]) {
+  fprintf(stderr, "SDL support not enabled in %s.\n", argv[0]);
+  (void)argc;
+  return 0;
+}
+
+#endif

extras/webp_quality.c

@@ -0,0 +1,54 @@
+// Simple tool to roughly evaluate the quality encoding of a webp bitstream
+//
+// Result is a *rough* estimation of the quality. You should just consider
+// the bucket it's in (q > 80? > 50? > 20?) and not take it for face value.
+/*
+ gcc -o webp_quality webp_quality.c -O3 -I../ -L. -L../imageio \
+    -limageio_util -lwebpextras -lwebp -lm -lpthread
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "extras/extras.h"
+#include "imageio/imageio_util.h"
+#include "../examples/unicode.h"
+
+int main(int argc, const char* argv[]) {
+  int c;
+  int quiet = 0;
+  int ok = 1;
+
+  INIT_WARGV(argc, argv);
+
+  for (c = 1; ok && c < argc; ++c) {
+    if (!strcmp(argv[c], "-quiet")) {
+      quiet = 1;
+    } else if (!strcmp(argv[c], "-help") || !strcmp(argv[c], "-h")) {
+      printf("webp_quality [-h][-quiet] webp_files...\n");
+      FREE_WARGV_AND_RETURN(0);
+    } else {
+      const char* const filename = (const char*)GET_WARGV(argv, c);
+      const uint8_t* data = NULL;
+      size_t data_size = 0;
+      int q;
+      ok = ImgIoUtilReadFile(filename, &data, &data_size);
+      if (!ok) break;
+      q = VP8EstimateQuality(data, data_size);
+      if (!quiet) WPRINTF("[%s] ", (const W_CHAR*)filename);
+      if (q < 0) {
+        fprintf(stderr, "Not a WebP file, or not a lossy WebP file.\n");
+        ok = 0;
+      } else {
+        if (!quiet) {
+          printf("Estimated quality factor: %d\n", q);
+        } else {
+          printf("%d\n", q);   // just print the number
+        }
+      }
+      free((void*)data);
+    }
+  }
+  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+}

extras/webp_to_sdl.c

@@ -0,0 +1,110 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Simple WebP-to-SDL wrapper. Useful for emscripten.
+//
+// Author: James Zern (jzern@google.com)
+
+#ifdef HAVE_CONFIG_H
+#include "src/webp/config.h"
+#endif
+
+#if defined(WEBP_HAVE_SDL)
+
+#include "webp_to_sdl.h"
+
+#include <stdio.h>
+#include "src/webp/decode.h"
+
+#if defined(WEBP_HAVE_JUST_SDL_H)
+#include <SDL.h>
+#else
+#include <SDL/SDL.h>
+#endif
+
+static int init_ok = 0;
+int WebPToSDL(const char* data, unsigned int data_size) {
+  int ok = 0;
+  VP8StatusCode status;
+  WebPDecoderConfig config;
+  WebPBitstreamFeatures* const input = &config.input;
+  WebPDecBuffer* const output = &config.output;
+  SDL_Surface* screen = NULL;
+  SDL_Surface* surface = NULL;
+
+  if (!WebPInitDecoderConfig(&config)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    return 0;
+  }
+
+  if (!init_ok) {
+    SDL_Init(SDL_INIT_VIDEO);
+    init_ok = 1;
+  }
+
+  status = WebPGetFeatures((uint8_t*)data, (size_t)data_size, &config.input);
+  if (status != VP8_STATUS_OK) goto Error;
+
+  screen = SDL_SetVideoMode(input->width, input->height, 32, SDL_SWSURFACE);
+  if (screen == NULL) {
+    fprintf(stderr, "Unable to set video mode (32bpp %dx%d)!\n",
+            input->width, input->height);
+    goto Error;
+  }
+
+  surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
+                                 input->width, input->height, 32,
+                                 0x000000ffu,   // R mask
+                                 0x0000ff00u,   // G mask
+                                 0x00ff0000u,   // B mask
+                                 0xff000000u);  // A mask
+
+  if (surface == NULL) {
+    fprintf(stderr, "Unable to create %dx%d RGBA surface!\n",
+            input->width, input->height);
+    goto Error;
+  }
+  if (SDL_MUSTLOCK(surface)) SDL_LockSurface(surface);
+
+#if SDL_BYTEORDER == SDL_BIG_ENDIAN
+  output->colorspace = MODE_BGRA;
+#else
+  output->colorspace = MODE_RGBA;
+#endif
+  output->width  = surface->w;
+  output->height = surface->h;
+  output->u.RGBA.rgba   = surface->pixels;
+  output->u.RGBA.stride = surface->pitch;
+  output->u.RGBA.size   = surface->pitch * surface->h;
+  output->is_external_memory = 1;
+
+  status = WebPDecode((const uint8_t*)data, (size_t)data_size, &config);
+  if (status != VP8_STATUS_OK) {
+    fprintf(stderr, "Error decoding image (%d)\n", status);
+    goto Error;
+  }
+
+  if (SDL_MUSTLOCK(surface)) SDL_UnlockSurface(surface);
+  if (SDL_BlitSurface(surface, NULL, screen, NULL) ||
+      SDL_Flip(screen)) {
+    goto Error;
+  }
+
+  ok = 1;
+
+ Error:
+  SDL_FreeSurface(surface);
+  SDL_FreeSurface(screen);
+  WebPFreeDecBuffer(output);
+  return ok;
+}
+
+//------------------------------------------------------------------------------
+
+#endif  // WEBP_HAVE_SDL

extras/webp_to_sdl.h

@@ -0,0 +1,22 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Simple WebP-to-SDL wrapper. Useful for emscripten.
+//
+// Author: James Zern (jzern@google.com)
+
+#ifndef WEBP_EXTRAS_WEBP_TO_SDL_H_
+#define WEBP_EXTRAS_WEBP_TO_SDL_H_
+
+// Exports the method WebPToSDL(const char* data, int data_size) which decodes
+// a WebP bitstream into an RGBA SDL surface.
+// Return false on failure.
+extern int WebPToSDL(const char* data, unsigned int data_size);
+
+#endif  // WEBP_EXTRAS_WEBP_TO_SDL_H_

gradle.properties

@@ -0,0 +1,14 @@
+# Project-wide Gradle settings.
+
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+
+# Versions for gradle
+BUILD_TOOLS_VERSION=23.0.3
+COMPILE_SDK_VERSION=23
+ANDROID_GRADLE_PLUGIN_VERSION=1.5.0
+GRADLE_DOWNLOAD_TASK_VERSION=2.1.0

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.1.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,183 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,100 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

imageio/Android.mk

@@ -0,0 +1,57 @@
+# Ignore this file during non-NDK builds.
+ifdef NDK_ROOT
+LOCAL_PATH := $(call my-dir)
+
+################################################################################
+# libimageio_util
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    imageio_util.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
+
+LOCAL_MODULE := imageio_util
+
+include $(BUILD_STATIC_LIBRARY)
+
+################################################################################
+# libimagedec
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    image_dec.c \
+    jpegdec.c \
+    metadata.c \
+    pngdec.c \
+    pnmdec.c \
+    tiffdec.c \
+    webpdec.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
+LOCAL_STATIC_LIBRARIES := imageio_util
+
+LOCAL_MODULE := imagedec
+
+include $(BUILD_STATIC_LIBRARY)
+
+################################################################################
+# libimageenc
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    image_enc.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
+LOCAL_STATIC_LIBRARIES := imageio_util
+
+LOCAL_MODULE := imageenc
+
+include $(BUILD_STATIC_LIBRARY)
+endif  # NDK_ROOT

imageio/Makefile.am

@@ -0,0 +1,32 @@
+AM_CPPFLAGS += -I$(top_builddir)/src -I$(top_srcdir)/src
+noinst_LTLIBRARIES =
+noinst_LTLIBRARIES += libimageio_util.la
+if BUILD_DEMUX
+  noinst_LTLIBRARIES += libimagedec.la
+endif
+noinst_LTLIBRARIES += libimageenc.la
+
+noinst_HEADERS =
+noinst_HEADERS += ../src/webp/decode.h
+noinst_HEADERS += ../src/webp/types.h
+
+libimageio_util_la_SOURCES =
+libimageio_util_la_SOURCES += imageio_util.c imageio_util.h
+
+libimagedec_la_SOURCES  =
+libimagedec_la_SOURCES += image_dec.c image_dec.h
+libimagedec_la_SOURCES += jpegdec.c jpegdec.h
+libimagedec_la_SOURCES += metadata.c metadata.h
+libimagedec_la_SOURCES += pngdec.c pngdec.h
+libimagedec_la_SOURCES += pnmdec.c pnmdec.h
+libimagedec_la_SOURCES += tiffdec.c tiffdec.h
+libimagedec_la_SOURCES += webpdec.c webpdec.h
+libimagedec_la_SOURCES += wicdec.c wicdec.h
+libimagedec_la_CPPFLAGS = $(JPEG_INCLUDES) $(PNG_INCLUDES) $(TIFF_INCLUDES)
+libimagedec_la_CPPFLAGS += $(AM_CPPFLAGS)
+libimagedec_la_LIBADD = ../src/demux/libwebpdemux.la
+
+libimageenc_la_SOURCES  =
+libimageenc_la_SOURCES += image_enc.c image_enc.h
+libimageenc_la_CPPFLAGS = $(JPEG_INCLUDES) $(PNG_INCLUDES) $(TIFF_INCLUDES)
+libimageenc_la_CPPFLAGS += $(AM_CPPFLAGS)

imageio/image_dec.c

@@ -0,0 +1,84 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Generic image-type guessing.
+
+#include "./image_dec.h"
+
+const char* WebPGetEnabledInputFileFormats(void) {
+  return "WebP"
+#ifdef WEBP_HAVE_JPEG
+         ", JPEG"
+#endif
+#ifdef WEBP_HAVE_PNG
+         ", PNG"
+#endif
+         ", PNM (PGM, PPM, PAM)"
+#ifdef WEBP_HAVE_TIFF
+         ", TIFF"
+#endif
+#ifdef HAVE_WINCODEC_H
+         ", Windows Imaging Component (WIC)"
+#endif
+         "";
+}
+
+static WEBP_INLINE uint32_t GetBE32(const uint8_t buf[]) {
+  return ((uint32_t)buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
+}
+
+WebPInputFileFormat WebPGuessImageType(const uint8_t* const data,
+                                       size_t data_size) {
+  WebPInputFileFormat format = WEBP_UNSUPPORTED_FORMAT;
+  if (data != NULL && data_size >= 12) {
+    const uint32_t magic1 = GetBE32(data + 0);
+    const uint32_t magic2 = GetBE32(data + 8);
+    if (magic1 == 0x89504E47U) {
+      format = WEBP_PNG_FORMAT;
+    } else if (magic1 >= 0xFFD8FF00U && magic1 <= 0xFFD8FFFFU) {
+      format = WEBP_JPEG_FORMAT;
+    } else if (magic1 == 0x49492A00 || magic1 == 0x4D4D002A) {
+      format = WEBP_TIFF_FORMAT;
+    } else if (magic1 == 0x52494646 && magic2 == 0x57454250) {
+      format = WEBP_WEBP_FORMAT;
+    } else if (((magic1 >> 24) & 0xff) == 'P') {
+      const int type = (magic1 >> 16) & 0xff;
+      // we only support 'P5 -> P7' for now.
+      if (type >= '5' && type <= '7') format = WEBP_PNM_FORMAT;
+    }
+  }
+  return format;
+}
+
+static int FailReader(const uint8_t* const data, size_t data_size,
+                      struct WebPPicture* const pic,
+                      int keep_alpha, struct Metadata* const metadata) {
+  (void)data;
+  (void)data_size;
+  (void)pic;
+  (void)keep_alpha;
+  (void)metadata;
+  return 0;
+}
+
+WebPImageReader WebPGetImageReader(WebPInputFileFormat format) {
+  switch (format) {
+    case WEBP_PNG_FORMAT: return ReadPNG;
+    case WEBP_JPEG_FORMAT: return ReadJPEG;
+    case WEBP_TIFF_FORMAT: return ReadTIFF;
+    case WEBP_WEBP_FORMAT: return ReadWebP;
+    case WEBP_PNM_FORMAT: return ReadPNM;
+    default: return FailReader;
+  }
+}
+
+WebPImageReader WebPGuessImageReader(const uint8_t* const data,
+                                     size_t data_size) {
+  return WebPGetImageReader(WebPGuessImageType(data, data_size));
+}

imageio/image_dec.h

@@ -0,0 +1,70 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  All-in-one library to decode PNG/JPEG/WebP/TIFF/WIC input images.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#ifndef WEBP_IMAGEIO_IMAGE_DEC_H_
+#define WEBP_IMAGEIO_IMAGE_DEC_H_
+
+#include "webp/types.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "./metadata.h"
+#include "./jpegdec.h"
+#include "./pngdec.h"
+#include "./pnmdec.h"
+#include "./tiffdec.h"
+#include "./webpdec.h"
+#include "./wicdec.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+  WEBP_PNG_FORMAT = 0,
+  WEBP_JPEG_FORMAT,
+  WEBP_TIFF_FORMAT,
+  WEBP_WEBP_FORMAT,
+  WEBP_PNM_FORMAT,
+  WEBP_UNSUPPORTED_FORMAT
+} WebPInputFileFormat;
+
+// Returns a comma separated list of enabled input formats.
+const char* WebPGetEnabledInputFileFormats(void);
+
+// Try to infer the image format. 'data_size' should be larger than 12.
+// Returns WEBP_UNSUPPORTED_FORMAT if format can't be guess safely.
+WebPInputFileFormat WebPGuessImageType(const uint8_t* const data,
+                                       size_t data_size);
+
+// Signature for common image-reading functions (ReadPNG, ReadJPEG, ...)
+typedef int (*WebPImageReader)(const uint8_t* const data, size_t data_size,
+                               struct WebPPicture* const pic,
+                               int keep_alpha, struct Metadata* const metadata);
+
+// Return the reader associated to a given file format.
+WebPImageReader WebPGetImageReader(WebPInputFileFormat format);
+
+// This function is similar to WebPGuessImageType(), but returns a
+// suitable reader function. The returned reader is never NULL, but
+// unknown formats will return an always-failing valid reader.
+WebPImageReader WebPGuessImageReader(const uint8_t* const data,
+                                     size_t data_size);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_IMAGE_DEC_H_

imageio/image_enc.c

@@ -0,0 +1,615 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Save image
+
+#include "./image_enc.h"
+
+#include <assert.h>
+#include <string.h>
+
+#ifdef WEBP_HAVE_PNG
+#include <png.h>
+#include <setjmp.h>   // note: this must be included *after* png.h
+#endif
+
+#ifdef HAVE_WINCODEC_H
+#ifdef __MINGW32__
+#define INITGUID  // Without this GUIDs are declared extern and fail to link
+#endif
+#define CINTERFACE
+#define COBJMACROS
+#define _WIN32_IE 0x500  // Workaround bug in shlwapi.h when compiling C++
+                         // code with COBJMACROS.
+#include <ole2.h>  // CreateStreamOnHGlobal()
+#include <shlwapi.h>
+#include <tchar.h>
+#include <windows.h>
+#include <wincodec.h>
+#endif
+
+#include "./imageio_util.h"
+#include "../examples/unicode.h"
+
+//------------------------------------------------------------------------------
+// PNG
+
+#ifdef HAVE_WINCODEC_H
+
+#define IFS(fn)                                                     \
+  do {                                                              \
+    if (SUCCEEDED(hr)) {                                            \
+      hr = (fn);                                                    \
+      if (FAILED(hr)) fprintf(stderr, #fn " failed %08lx\n", hr);   \
+    }                                                               \
+  } while (0)
+
+#ifdef __cplusplus
+#define MAKE_REFGUID(x) (x)
+#else
+#define MAKE_REFGUID(x) &(x)
+#endif
+
+static HRESULT CreateOutputStream(const char* out_file_name,
+                                  int write_to_mem, IStream** stream) {
+  HRESULT hr = S_OK;
+  if (write_to_mem) {
+    // Output to a memory buffer. This is freed when 'stream' is released.
+    IFS(CreateStreamOnHGlobal(NULL, TRUE, stream));
+  } else {
+    IFS(SHCreateStreamOnFile((const LPTSTR)out_file_name,
+                             STGM_WRITE | STGM_CREATE, stream));
+  }
+  if (FAILED(hr)) {
+    _ftprintf(stderr, _T("Error opening output file %s (%08lx)\n"),
+              (const LPTSTR)out_file_name, hr);
+  }
+  return hr;
+}
+
+static HRESULT WriteUsingWIC(const char* out_file_name, int use_stdout,
+                             REFGUID container_guid,
+                             uint8_t* rgb, int stride,
+                             uint32_t width, uint32_t height, int has_alpha) {
+  HRESULT hr = S_OK;
+  IWICImagingFactory* factory = NULL;
+  IWICBitmapFrameEncode* frame = NULL;
+  IWICBitmapEncoder* encoder = NULL;
+  IStream* stream = NULL;
+  WICPixelFormatGUID pixel_format = has_alpha ? GUID_WICPixelFormat32bppBGRA
+                                              : GUID_WICPixelFormat24bppBGR;
+
+  if (out_file_name == NULL || rgb == NULL) return E_INVALIDARG;
+
+  IFS(CoInitialize(NULL));
+  IFS(CoCreateInstance(MAKE_REFGUID(CLSID_WICImagingFactory), NULL,
+                       CLSCTX_INPROC_SERVER,
+                       MAKE_REFGUID(IID_IWICImagingFactory),
+                       (LPVOID*)&factory));
+  if (hr == REGDB_E_CLASSNOTREG) {
+    fprintf(stderr,
+            "Couldn't access Windows Imaging Component (are you running "
+            "Windows XP SP3 or newer?). PNG support not available. "
+            "Use -ppm or -pgm for available PPM and PGM formats.\n");
+  }
+  IFS(CreateOutputStream(out_file_name, use_stdout, &stream));
+  IFS(IWICImagingFactory_CreateEncoder(factory, container_guid, NULL,
+                                       &encoder));
+  IFS(IWICBitmapEncoder_Initialize(encoder, stream,
+                                   WICBitmapEncoderNoCache));
+  IFS(IWICBitmapEncoder_CreateNewFrame(encoder, &frame, NULL));
+  IFS(IWICBitmapFrameEncode_Initialize(frame, NULL));
+  IFS(IWICBitmapFrameEncode_SetSize(frame, width, height));
+  IFS(IWICBitmapFrameEncode_SetPixelFormat(frame, &pixel_format));
+  IFS(IWICBitmapFrameEncode_WritePixels(frame, height, stride,
+                                        height * stride, rgb));
+  IFS(IWICBitmapFrameEncode_Commit(frame));
+  IFS(IWICBitmapEncoder_Commit(encoder));
+
+  if (SUCCEEDED(hr) && use_stdout) {
+    HGLOBAL image;
+    IFS(GetHGlobalFromStream(stream, &image));
+    if (SUCCEEDED(hr)) {
+      HANDLE std_output = GetStdHandle(STD_OUTPUT_HANDLE);
+      DWORD mode;
+      const BOOL update_mode = GetConsoleMode(std_output, &mode);
+      const void* const image_mem = GlobalLock(image);
+      DWORD bytes_written = 0;
+
+      // Clear output processing if necessary, then output the image.
+      if (update_mode) SetConsoleMode(std_output, 0);
+      if (!WriteFile(std_output, image_mem, (DWORD)GlobalSize(image),
+                     &bytes_written, NULL) ||
+          bytes_written != GlobalSize(image)) {
+        hr = E_FAIL;
+      }
+      if (update_mode) SetConsoleMode(std_output, mode);
+      GlobalUnlock(image);
+    }
+  }
+
+  if (frame != NULL) IUnknown_Release(frame);
+  if (encoder != NULL) IUnknown_Release(encoder);
+  if (factory != NULL) IUnknown_Release(factory);
+  if (stream != NULL) IUnknown_Release(stream);
+  return hr;
+}
+
+int WebPWritePNG(const char* out_file_name, int use_stdout,
+                 const WebPDecBuffer* const buffer) {
+  const uint32_t width = buffer->width;
+  const uint32_t height = buffer->height;
+  uint8_t* const rgb = buffer->u.RGBA.rgba;
+  const int stride = buffer->u.RGBA.stride;
+  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
+
+  return SUCCEEDED(WriteUsingWIC(out_file_name, use_stdout,
+                                 MAKE_REFGUID(GUID_ContainerFormatPng),
+                                 rgb, stride, width, height, has_alpha));
+}
+
+#elif defined(WEBP_HAVE_PNG)    // !HAVE_WINCODEC_H
+static void PNGAPI PNGErrorFunction(png_structp png, png_const_charp unused) {
+  (void)unused;  // remove variable-unused warning
+  longjmp(png_jmpbuf(png), 1);
+}
+
+int WebPWritePNG(FILE* out_file, const WebPDecBuffer* const buffer) {
+  volatile png_structp png;
+  volatile png_infop info;
+
+  if (out_file == NULL || buffer == NULL) return 0;
+
+  png = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+                                NULL, PNGErrorFunction, NULL);
+  if (png == NULL) {
+    return 0;
+  }
+  info = png_create_info_struct(png);
+  if (info == NULL) {
+    png_destroy_write_struct((png_structpp)&png, NULL);
+    return 0;
+  }
+  if (setjmp(png_jmpbuf(png))) {
+    png_destroy_write_struct((png_structpp)&png, (png_infopp)&info);
+    return 0;
+  }
+  png_init_io(png, out_file);
+  {
+    const uint32_t width = buffer->width;
+    const uint32_t height = buffer->height;
+    png_bytep row = buffer->u.RGBA.rgba;
+    const int stride = buffer->u.RGBA.stride;
+    const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
+    uint32_t y;
+
+    png_set_IHDR(png, info, width, height, 8,
+                 has_alpha ? PNG_COLOR_TYPE_RGBA : PNG_COLOR_TYPE_RGB,
+                 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
+                 PNG_FILTER_TYPE_DEFAULT);
+    png_write_info(png, info);
+    for (y = 0; y < height; ++y) {
+      png_write_rows(png, &row, 1);
+      row += stride;
+    }
+  }
+  png_write_end(png, info);
+  png_destroy_write_struct((png_structpp)&png, (png_infopp)&info);
+  return 1;
+}
+#else    // !HAVE_WINCODEC_H && !WEBP_HAVE_PNG
+int WebPWritePNG(FILE* fout, const WebPDecBuffer* const buffer) {
+  if (fout == NULL || buffer == NULL) return 0;
+
+  fprintf(stderr, "PNG support not compiled. Please install the libpng "
+          "development package before building.\n");
+  fprintf(stderr, "You can run with -ppm flag to decode in PPM format.\n");
+  return 0;
+}
+#endif
+
+//------------------------------------------------------------------------------
+// PPM / PAM
+
+static int WritePPMPAM(FILE* fout, const WebPDecBuffer* const buffer,
+                       int alpha) {
+  if (fout == NULL || buffer == NULL) {
+    return 0;
+  } else {
+    const uint32_t width = buffer->width;
+    const uint32_t height = buffer->height;
+    const uint8_t* row = buffer->u.RGBA.rgba;
+    const int stride = buffer->u.RGBA.stride;
+    const size_t bytes_per_px = alpha ? 4 : 3;
+    uint32_t y;
+
+    if (row == NULL) return 0;
+
+    if (alpha) {
+      fprintf(fout, "P7\nWIDTH %u\nHEIGHT %u\nDEPTH 4\nMAXVAL 255\n"
+                    "TUPLTYPE RGB_ALPHA\nENDHDR\n", width, height);
+    } else {
+      fprintf(fout, "P6\n%u %u\n255\n", width, height);
+    }
+    for (y = 0; y < height; ++y) {
+      if (fwrite(row, width, bytes_per_px, fout) != bytes_per_px) {
+        return 0;
+      }
+      row += stride;
+    }
+  }
+  return 1;
+}
+
+int WebPWritePPM(FILE* fout, const WebPDecBuffer* const buffer) {
+  return WritePPMPAM(fout, buffer, 0);
+}
+
+int WebPWritePAM(FILE* fout, const WebPDecBuffer* const buffer) {
+  return WritePPMPAM(fout, buffer, 1);
+}
+
+//------------------------------------------------------------------------------
+// Raw PGM
+
+// Save 16b mode (RGBA4444, RGB565, ...) for debugging purpose.
+int WebPWrite16bAsPGM(FILE* fout, const WebPDecBuffer* const buffer) {
+  const uint32_t width = buffer->width;
+  const uint32_t height = buffer->height;
+  const uint8_t* rgba = buffer->u.RGBA.rgba;
+  const int stride = buffer->u.RGBA.stride;
+  const uint32_t bytes_per_px = 2;
+  uint32_t y;
+
+  if (fout == NULL || buffer == NULL || rgba == NULL) return 0;
+
+  fprintf(fout, "P5\n%u %u\n255\n", width * bytes_per_px, height);
+  for (y = 0; y < height; ++y) {
+    if (fwrite(rgba, width, bytes_per_px, fout) != bytes_per_px) {
+      return 0;
+    }
+    rgba += stride;
+  }
+  return 1;
+}
+
+//------------------------------------------------------------------------------
+// BMP (see https://en.wikipedia.org/wiki/BMP_file_format#Pixel_storage)
+
+static void PutLE16(uint8_t* const dst, uint32_t value) {
+  dst[0] = (value >> 0) & 0xff;
+  dst[1] = (value >> 8) & 0xff;
+}
+
+static void PutLE32(uint8_t* const dst, uint32_t value) {
+  PutLE16(dst + 0, (value >>  0) & 0xffff);
+  PutLE16(dst + 2, (value >> 16) & 0xffff);
+}
+
+#define BMP_HEADER_SIZE 54
+#define BMP_HEADER_ALPHA_EXTRA_SIZE 16  // for alpha info
+int WebPWriteBMP(FILE* fout, const WebPDecBuffer* const buffer) {
+  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
+  const int header_size =
+      BMP_HEADER_SIZE + (has_alpha ? BMP_HEADER_ALPHA_EXTRA_SIZE : 0);
+  const uint32_t width = buffer->width;
+  const uint32_t height = buffer->height;
+  const uint8_t* rgba = buffer->u.RGBA.rgba;
+  const int stride = buffer->u.RGBA.stride;
+  const uint32_t bytes_per_px = has_alpha ? 4 : 3;
+  uint32_t y;
+  const uint32_t line_size = bytes_per_px * width;
+  const uint32_t bmp_stride = (line_size + 3) & ~3;   // pad to 4
+  const uint32_t image_size = bmp_stride * height;
+  const uint32_t total_size =  image_size + header_size;
+  uint8_t bmp_header[BMP_HEADER_SIZE + BMP_HEADER_ALPHA_EXTRA_SIZE] = { 0 };
+
+  if (fout == NULL || buffer == NULL || rgba == NULL) return 0;
+
+  // bitmap file header
+  PutLE16(bmp_header + 0, 0x4d42);                // signature 'BM'
+  PutLE32(bmp_header + 2, total_size);            // size including header
+  PutLE32(bmp_header + 6, 0);                     // reserved
+  PutLE32(bmp_header + 10, header_size);          // offset to pixel array
+  // bitmap info header
+  PutLE32(bmp_header + 14, header_size - 14);     // DIB header size
+  PutLE32(bmp_header + 18, width);                // dimensions
+  PutLE32(bmp_header + 22, height);               // no vertical flip
+  PutLE16(bmp_header + 26, 1);                    // number of planes
+  PutLE16(bmp_header + 28, bytes_per_px * 8);     // bits per pixel
+  PutLE32(bmp_header + 30, has_alpha ? 3 : 0);    // BI_BITFIELDS or BI_RGB
+  PutLE32(bmp_header + 34, image_size);
+  PutLE32(bmp_header + 38, 2400);                 // x pixels/meter
+  PutLE32(bmp_header + 42, 2400);                 // y pixels/meter
+  PutLE32(bmp_header + 46, 0);                    // number of palette colors
+  PutLE32(bmp_header + 50, 0);                    // important color count
+  if (has_alpha) {  // BITMAPV3INFOHEADER complement
+    PutLE32(bmp_header + 54, 0x00ff0000);         // red mask
+    PutLE32(bmp_header + 58, 0x0000ff00);         // green mask
+    PutLE32(bmp_header + 62, 0x000000ff);         // blue mask
+    PutLE32(bmp_header + 66, 0xff000000);         // alpha mask
+  }
+
+  // TODO(skal): color profile
+
+  // write header
+  if (fwrite(bmp_header, header_size, 1, fout) != 1) {
+    return 0;
+  }
+
+  // write pixel array, bottom to top
+  for (y = 0; y < height; ++y) {
+    const uint8_t* const src = &rgba[(uint64_t)(height - 1 - y) * stride];
+    if (fwrite(src, line_size, 1, fout) != 1) {
+      return 0;
+    }
+    // write padding zeroes
+    if (bmp_stride != line_size) {
+      const uint8_t zeroes[3] = { 0 };
+      if (fwrite(zeroes, bmp_stride - line_size, 1, fout) != 1) {
+        return 0;
+      }
+    }
+  }
+  return 1;
+}
+#undef BMP_HEADER_SIZE
+#undef BMP_HEADER_ALPHA_EXTRA_SIZE
+
+//------------------------------------------------------------------------------
+// TIFF
+
+#define NUM_IFD_ENTRIES 15
+#define EXTRA_DATA_SIZE 16
+// 10b for signature/header + n * 12b entries + 4b for IFD terminator:
+#define EXTRA_DATA_OFFSET (10 + 12 * NUM_IFD_ENTRIES + 4)
+#define TIFF_HEADER_SIZE (EXTRA_DATA_OFFSET + EXTRA_DATA_SIZE)
+
+int WebPWriteTIFF(FILE* fout, const WebPDecBuffer* const buffer) {
+  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
+  const uint32_t width = buffer->width;
+  const uint32_t height = buffer->height;
+  const uint8_t* rgba = buffer->u.RGBA.rgba;
+  const int stride = buffer->u.RGBA.stride;
+  const uint8_t bytes_per_px = has_alpha ? 4 : 3;
+  const uint8_t assoc_alpha =
+      WebPIsPremultipliedMode(buffer->colorspace) ? 1 : 2;
+  // For non-alpha case, we omit tag 0x152 (ExtraSamples).
+  const uint8_t num_ifd_entries = has_alpha ? NUM_IFD_ENTRIES
+                                            : NUM_IFD_ENTRIES - 1;
+  uint8_t tiff_header[TIFF_HEADER_SIZE] = {
+    0x49, 0x49, 0x2a, 0x00,   // little endian signature
+    8, 0, 0, 0,               // offset to the unique IFD that follows
+    // IFD (offset = 8). Entries must be written in increasing tag order.
+    num_ifd_entries, 0,       // Number of entries in the IFD (12 bytes each).
+    0x00, 0x01, 3, 0, 1, 0, 0, 0, 0, 0, 0, 0,    //  10: Width  (TBD)
+    0x01, 0x01, 3, 0, 1, 0, 0, 0, 0, 0, 0, 0,    //  22: Height (TBD)
+    0x02, 0x01, 3, 0, bytes_per_px, 0, 0, 0,     //  34: BitsPerSample: 8888
+        EXTRA_DATA_OFFSET + 0, 0, 0, 0,
+    0x03, 0x01, 3, 0, 1, 0, 0, 0, 1, 0, 0, 0,    //  46: Compression: none
+    0x06, 0x01, 3, 0, 1, 0, 0, 0, 2, 0, 0, 0,    //  58: Photometric: RGB
+    0x11, 0x01, 4, 0, 1, 0, 0, 0,                //  70: Strips offset:
+        TIFF_HEADER_SIZE, 0, 0, 0,               //      data follows header
+    0x12, 0x01, 3, 0, 1, 0, 0, 0, 1, 0, 0, 0,    //  82: Orientation: topleft
+    0x15, 0x01, 3, 0, 1, 0, 0, 0,                //  94: SamplesPerPixels
+        bytes_per_px, 0, 0, 0,
+    0x16, 0x01, 3, 0, 1, 0, 0, 0, 0, 0, 0, 0,    // 106: Rows per strip (TBD)
+    0x17, 0x01, 4, 0, 1, 0, 0, 0, 0, 0, 0, 0,    // 118: StripByteCount (TBD)
+    0x1a, 0x01, 5, 0, 1, 0, 0, 0,                // 130: X-resolution
+        EXTRA_DATA_OFFSET + 8, 0, 0, 0,
+    0x1b, 0x01, 5, 0, 1, 0, 0, 0,                // 142: Y-resolution
+        EXTRA_DATA_OFFSET + 8, 0, 0, 0,
+    0x1c, 0x01, 3, 0, 1, 0, 0, 0, 1, 0, 0, 0,    // 154: PlanarConfiguration
+    0x28, 0x01, 3, 0, 1, 0, 0, 0, 2, 0, 0, 0,    // 166: ResolutionUnit (inch)
+    0x52, 0x01, 3, 0, 1, 0, 0, 0,
+        assoc_alpha, 0, 0, 0,                    // 178: ExtraSamples: rgbA/RGBA
+    0, 0, 0, 0,                                  // 190: IFD terminator
+    // EXTRA_DATA_OFFSET:
+    8, 0, 8, 0, 8, 0, 8, 0,      // BitsPerSample
+    72, 0, 0, 0, 1, 0, 0, 0      // 72 pixels/inch, for X/Y-resolution
+  };
+  uint32_t y;
+
+  if (fout == NULL || buffer == NULL || rgba == NULL) return 0;
+
+  // Fill placeholders in IFD:
+  PutLE32(tiff_header + 10 + 8, width);
+  PutLE32(tiff_header + 22 + 8, height);
+  PutLE32(tiff_header + 106 + 8, height);
+  PutLE32(tiff_header + 118 + 8, width * bytes_per_px * height);
+  if (!has_alpha) PutLE32(tiff_header + 178, 0);  // IFD terminator
+
+  // write header
+  if (fwrite(tiff_header, sizeof(tiff_header), 1, fout) != 1) {
+    return 0;
+  }
+  // write pixel values
+  for (y = 0; y < height; ++y) {
+    if (fwrite(rgba, bytes_per_px, width, fout) != width) {
+      return 0;
+    }
+    rgba += stride;
+  }
+
+  return 1;
+}
+
+#undef TIFF_HEADER_SIZE
+#undef EXTRA_DATA_OFFSET
+#undef EXTRA_DATA_SIZE
+#undef NUM_IFD_ENTRIES
+
+//------------------------------------------------------------------------------
+// Raw Alpha
+
+int WebPWriteAlphaPlane(FILE* fout, const WebPDecBuffer* const buffer) {
+  if (fout == NULL || buffer == NULL) {
+    return 0;
+  } else {
+    const uint32_t width = buffer->width;
+    const uint32_t height = buffer->height;
+    const uint8_t* a = buffer->u.YUVA.a;
+    const int a_stride = buffer->u.YUVA.a_stride;
+    uint32_t y;
+
+    if (a == NULL) return 0;
+
+    fprintf(fout, "P5\n%u %u\n255\n", width, height);
+    for (y = 0; y < height; ++y) {
+      if (fwrite(a, width, 1, fout) != 1) return 0;
+      a += a_stride;
+    }
+    return 1;
+  }
+}
+
+//------------------------------------------------------------------------------
+// PGM with IMC4 layout
+
+int WebPWritePGM(FILE* fout, const WebPDecBuffer* const buffer) {
+  if (fout == NULL || buffer == NULL) {
+    return 0;
+  } else {
+    const int width = buffer->width;
+    const int height = buffer->height;
+    const WebPYUVABuffer* const yuv = &buffer->u.YUVA;
+    const uint8_t* src_y = yuv->y;
+    const uint8_t* src_u = yuv->u;
+    const uint8_t* src_v = yuv->v;
+    const uint8_t* src_a = yuv->a;
+    const int uv_width = (width + 1) / 2;
+    const int uv_height = (height + 1) / 2;
+    const int a_height = (src_a != NULL) ? height : 0;
+    int ok = 1;
+    int y;
+
+    if (src_y == NULL || src_u == NULL || src_v == NULL) return 0;
+
+    fprintf(fout, "P5\n%d %d\n255\n",
+            (width + 1) & ~1, height + uv_height + a_height);
+    for (y = 0; ok && y < height; ++y) {
+      ok &= (fwrite(src_y, width, 1, fout) == 1);
+      if (width & 1) fputc(0, fout);    // padding byte
+      src_y += yuv->y_stride;
+    }
+    for (y = 0; ok && y < uv_height; ++y) {
+      ok &= (fwrite(src_u, uv_width, 1, fout) == 1);
+      ok &= (fwrite(src_v, uv_width, 1, fout) == 1);
+      src_u += yuv->u_stride;
+      src_v += yuv->v_stride;
+    }
+    for (y = 0; ok && y < a_height; ++y) {
+      ok &= (fwrite(src_a, width, 1, fout) == 1);
+      if (width & 1) fputc(0, fout);    // padding byte
+      src_a += yuv->a_stride;
+    }
+    return ok;
+  }
+}
+
+//------------------------------------------------------------------------------
+// Raw YUV(A) planes
+
+int WebPWriteYUV(FILE* fout, const WebPDecBuffer* const buffer) {
+  if (fout == NULL || buffer == NULL) {
+    return 0;
+  } else {
+    const int width = buffer->width;
+    const int height = buffer->height;
+    const WebPYUVABuffer* const yuv = &buffer->u.YUVA;
+    const uint8_t* src_y = yuv->y;
+    const uint8_t* src_u = yuv->u;
+    const uint8_t* src_v = yuv->v;
+    const uint8_t* src_a = yuv->a;
+    const int uv_width = (width + 1) / 2;
+    const int uv_height = (height + 1) / 2;
+    const int a_height = (src_a != NULL) ? height : 0;
+    int ok = 1;
+    int y;
+
+    if (src_y == NULL || src_u == NULL || src_v == NULL) return 0;
+
+    for (y = 0; ok && y < height; ++y) {
+      ok &= (fwrite(src_y, width, 1, fout) == 1);
+      src_y += yuv->y_stride;
+    }
+    for (y = 0; ok && y < uv_height; ++y) {
+      ok &= (fwrite(src_u, uv_width, 1, fout) == 1);
+      src_u += yuv->u_stride;
+    }
+    for (y = 0; ok && y < uv_height; ++y) {
+      ok &= (fwrite(src_v, uv_width, 1, fout) == 1);
+      src_v += yuv->v_stride;
+    }
+    for (y = 0; ok && y < a_height; ++y) {
+      ok &= (fwrite(src_a, width, 1, fout) == 1);
+      src_a += yuv->a_stride;
+    }
+    return ok;
+  }
+}
+
+//------------------------------------------------------------------------------
+// Generic top-level call
+
+int WebPSaveImage(const WebPDecBuffer* const buffer,
+                  WebPOutputFileFormat format,
+                  const char* const out_file_name) {
+  FILE* fout = NULL;
+  int needs_open_file = 1;
+  const int use_stdout =
+      (out_file_name != NULL) && !WSTRCMP(out_file_name, "-");
+  int ok = 1;
+
+  if (buffer == NULL || out_file_name == NULL) return 0;
+
+#ifdef HAVE_WINCODEC_H
+  needs_open_file = (format != PNG);
+#endif
+
+  if (needs_open_file) {
+    fout = use_stdout ? ImgIoUtilSetBinaryMode(stdout)
+                      : WFOPEN(out_file_name, "wb");
+    if (fout == NULL) {
+      WFPRINTF(stderr, "Error opening output file %s\n",
+               (const W_CHAR*)out_file_name);
+      return 0;
+    }
+  }
+
+  if (format == PNG ||
+      format == RGBA || format == BGRA || format == ARGB ||
+      format == rgbA || format == bgrA || format == Argb) {
+#ifdef HAVE_WINCODEC_H
+    ok &= WebPWritePNG(out_file_name, use_stdout, buffer);
+#else
+    ok &= WebPWritePNG(fout, buffer);
+#endif
+  } else if (format == PAM) {
+    ok &= WebPWritePAM(fout, buffer);
+  } else if (format == PPM || format == RGB || format == BGR) {
+    ok &= WebPWritePPM(fout, buffer);
+  } else if (format == RGBA_4444 || format == RGB_565 || format == rgbA_4444) {
+    ok &= WebPWrite16bAsPGM(fout, buffer);
+  } else if (format == BMP) {
+    ok &= WebPWriteBMP(fout, buffer);
+  } else if (format == TIFF) {
+    ok &= WebPWriteTIFF(fout, buffer);
+  } else if (format == RAW_YUV) {
+    ok &= WebPWriteYUV(fout, buffer);
+  } else if (format == PGM || format == YUV || format == YUVA) {
+    ok &= WebPWritePGM(fout, buffer);
+  } else if (format == ALPHA_PLANE_ONLY) {
+    ok &= WebPWriteAlphaPlane(fout, buffer);
+  }
+  if (fout != NULL && fout != stdout) {
+    fclose(fout);
+  }
+  return ok;
+}

imageio/image_enc.h

@@ -0,0 +1,96 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  All-in-one library to save PNG/JPEG/WebP/TIFF/WIC images.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#ifndef WEBP_IMAGEIO_IMAGE_ENC_H_
+#define WEBP_IMAGEIO_IMAGE_ENC_H_
+
+#include <stdio.h>
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "webp/types.h"
+#include "webp/decode.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Output types
+typedef enum {
+  PNG = 0,
+  PAM,
+  PPM,
+  PGM,
+  BMP,
+  TIFF,
+  RAW_YUV,
+  ALPHA_PLANE_ONLY,  // this is for experimenting only
+  // forced colorspace output (for testing, mostly)
+  RGB, RGBA, BGR, BGRA, ARGB,
+  RGBA_4444, RGB_565,
+  rgbA, bgrA, Argb, rgbA_4444,
+  YUV, YUVA
+} WebPOutputFileFormat;
+
+// General all-purpose call.
+// Most formats expect a 'buffer' containing RGBA-like samples, except
+// RAW_YUV, YUV and YUVA formats.
+// If 'out_file_name' is "-", data is saved to stdout.
+// Returns false if an error occurred, true otherwise.
+int WebPSaveImage(const WebPDecBuffer* const buffer,
+                  WebPOutputFileFormat format, const char* const out_file_name);
+
+// Save to PNG.
+#ifdef HAVE_WINCODEC_H
+int WebPWritePNG(const char* out_file_name, int use_stdout,
+                 const struct WebPDecBuffer* const buffer);
+#else
+int WebPWritePNG(FILE* out_file, const WebPDecBuffer* const buffer);
+#endif
+
+// Save to PPM format (RGB, no alpha)
+int WebPWritePPM(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save to PAM format (= PPM + alpha)
+int WebPWritePAM(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save 16b mode (RGBA4444, RGB565, ...) for debugging purposes.
+int WebPWrite16bAsPGM(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save as BMP
+int WebPWriteBMP(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save as TIFF
+int WebPWriteTIFF(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save the ALPHA plane (only) as a PGM
+int WebPWriteAlphaPlane(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save as YUV samples as PGM format (using IMC4 layout).
+// See: https://www.fourcc.org/yuv.php#IMC4.
+// (very convenient format for viewing the samples, esp. for odd dimensions).
+int WebPWritePGM(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save YUV(A) planes sequentially (raw dump)
+int WebPWriteYUV(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save 16b mode (RGBA4444, RGB565, ...) as PGM format, for debugging purposes.
+int WebPWrite16bAsPGM(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_IMAGE_ENC_H_

imageio/imageio_util.c

@@ -0,0 +1,162 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Utility functions used by the image decoders.
+//
+
+#include "./imageio_util.h"
+
+#if defined(_WIN32)
+#include <fcntl.h>   // for _O_BINARY
+#include <io.h>      // for _setmode()
+#endif
+#include <stdlib.h>
+#include <string.h>
+#include "../examples/unicode.h"
+
+// -----------------------------------------------------------------------------
+// File I/O
+
+FILE* ImgIoUtilSetBinaryMode(FILE* file) {
+#if defined(_WIN32)
+  if (_setmode(_fileno(file), _O_BINARY) == -1) {
+    fprintf(stderr, "Failed to reopen file in O_BINARY mode.\n");
+    return NULL;
+  }
+#endif
+  return file;
+}
+
+int ImgIoUtilReadFromStdin(const uint8_t** data, size_t* data_size) {
+  static const size_t kBlockSize = 16384;  // default initial size
+  size_t max_size = 0;
+  size_t size = 0;
+  uint8_t* input = NULL;
+
+  if (data == NULL || data_size == NULL) return 0;
+  *data = NULL;
+  *data_size = 0;
+
+  if (!ImgIoUtilSetBinaryMode(stdin)) return 0;
+
+  while (!feof(stdin)) {
+    // We double the buffer size each time and read as much as possible.
+    const size_t extra_size = (max_size == 0) ? kBlockSize : max_size;
+    // we allocate one extra byte for the \0 terminator
+    void* const new_data = realloc(input, max_size + extra_size + 1);
+    if (new_data == NULL) goto Error;
+    input = (uint8_t*)new_data;
+    max_size += extra_size;
+    size += fread(input + size, 1, extra_size, stdin);
+    if (size < max_size) break;
+  }
+  if (ferror(stdin)) goto Error;
+  if (input != NULL) input[size] = '\0';  // convenient 0-terminator
+  *data = input;
+  *data_size = size;
+  return 1;
+
+ Error:
+  free(input);
+  fprintf(stderr, "Could not read from stdin\n");
+  return 0;
+}
+
+int ImgIoUtilReadFile(const char* const file_name,
+                      const uint8_t** data, size_t* data_size) {
+  int ok;
+  uint8_t* file_data;
+  size_t file_size;
+  FILE* in;
+  const int from_stdin = (file_name == NULL) || !WSTRCMP(file_name, "-");
+
+  if (from_stdin) return ImgIoUtilReadFromStdin(data, data_size);
+
+  if (data == NULL || data_size == NULL) return 0;
+  *data = NULL;
+  *data_size = 0;
+
+  in = WFOPEN(file_name, "rb");
+  if (in == NULL) {
+    WFPRINTF(stderr, "cannot open input file '%s'\n", (const W_CHAR*)file_name);
+    return 0;
+  }
+  fseek(in, 0, SEEK_END);
+  file_size = ftell(in);
+  fseek(in, 0, SEEK_SET);
+  // we allocate one extra byte for the \0 terminator
+  file_data = (uint8_t*)WebPMalloc(file_size + 1);
+  if (file_data == NULL) {
+    fclose(in);
+    WFPRINTF(stderr, "memory allocation failure when reading file %s\n",
+             (const W_CHAR*)file_name);
+    return 0;
+  }
+  ok = (fread(file_data, file_size, 1, in) == 1);
+  fclose(in);
+
+  if (!ok) {
+    WFPRINTF(stderr, "Could not read %d bytes of data from file %s\n",
+             (int)file_size, (const W_CHAR*)file_name);
+    WebPFree(file_data);
+    return 0;
+  }
+  file_data[file_size] = '\0';  // convenient 0-terminator
+  *data = file_data;
+  *data_size = file_size;
+  return 1;
+}
+
+// -----------------------------------------------------------------------------
+
+int ImgIoUtilWriteFile(const char* const file_name,
+                       const uint8_t* data, size_t data_size) {
+  int ok;
+  FILE* out;
+  const int to_stdout = (file_name == NULL) || !WSTRCMP(file_name, "-");
+
+  if (data == NULL) {
+    return 0;
+  }
+  out = to_stdout ? ImgIoUtilSetBinaryMode(stdout) : WFOPEN(file_name, "wb");
+  if (out == NULL) {
+    WFPRINTF(stderr, "Error! Cannot open output file '%s'\n",
+             (const W_CHAR*)file_name);
+    return 0;
+  }
+  ok = (fwrite(data, data_size, 1, out) == 1);
+  if (out != stdout) fclose(out);
+  return ok;
+}
+
+// -----------------------------------------------------------------------------
+
+void ImgIoUtilCopyPlane(const uint8_t* src, int src_stride,
+                        uint8_t* dst, int dst_stride, int width, int height) {
+  while (height-- > 0) {
+    memcpy(dst, src, width * sizeof(*dst));
+    src += src_stride;
+    dst += dst_stride;
+  }
+}
+
+// -----------------------------------------------------------------------------
+
+int ImgIoUtilCheckSizeArgumentsOverflow(uint64_t stride, size_t height) {
+  const uint64_t total_size = stride * height;
+  int ok = (total_size == (size_t)total_size);
+  // check that 'stride' is representable as int:
+  ok = ok && ((uint64_t)(int)stride == stride);
+#if defined(WEBP_MAX_IMAGE_SIZE)
+  ok = ok && (total_size <= (uint64_t)WEBP_MAX_IMAGE_SIZE);
+#endif
+  return ok;
+}
+
+// -----------------------------------------------------------------------------

imageio/imageio_util.h

@@ -0,0 +1,64 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Utility functions used by the image decoders.
+//
+
+#ifndef WEBP_IMAGEIO_IMAGEIO_UTIL_H_
+#define WEBP_IMAGEIO_IMAGEIO_UTIL_H_
+
+#include <stdio.h>
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+//------------------------------------------------------------------------------
+// File I/O
+
+// Reopen file in binary (O_BINARY) mode.
+// Returns 'file' on success, NULL otherwise.
+FILE* ImgIoUtilSetBinaryMode(FILE* file);
+
+// Allocates storage for entire file 'file_name' and returns contents and size
+// in 'data' and 'data_size'. Returns 1 on success, 0 otherwise. '*data' should
+// be deleted using WebPFree().
+// Note: for convenience, the data will be null-terminated with an extra byte
+// (not accounted for in *data_size), in case the file is text and intended
+// to be used as a C-string.
+// If 'file_name' is NULL or equal to "-", input is read from stdin by calling
+// the function ImgIoUtilReadFromStdin().
+int ImgIoUtilReadFile(const char* const file_name,
+                      const uint8_t** data, size_t* data_size);
+
+// Same as ImgIoUtilReadFile(), but reads until EOF from stdin instead.
+int ImgIoUtilReadFromStdin(const uint8_t** data, size_t* data_size);
+
+// Write a data segment into a file named 'file_name'. Returns true if ok.
+// If 'file_name' is NULL or equal to "-", output is written to stdout.
+int ImgIoUtilWriteFile(const char* const file_name,
+                       const uint8_t* data, size_t data_size);
+
+//------------------------------------------------------------------------------
+
+// Copy width x height pixels from 'src' to 'dst' honoring the strides.
+void ImgIoUtilCopyPlane(const uint8_t* src, int src_stride,
+                        uint8_t* dst, int dst_stride, int width, int height);
+
+//------------------------------------------------------------------------------
+
+// Returns 0 in case of overflow, memory over-allocation or excessive dimension.
+int ImgIoUtilCheckSizeArgumentsOverflow(uint64_t stride, size_t height);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_IMAGEIO_UTIL_H_

imageio/jpegdec.c

@@ -0,0 +1,364 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// JPEG decode.
+
+#include "./jpegdec.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include <stdio.h>
+
+#ifdef WEBP_HAVE_JPEG
+#include <jpeglib.h>
+#include <jerror.h>
+#include <setjmp.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/encode.h"
+#include "./imageio_util.h"
+#include "./metadata.h"
+
+// -----------------------------------------------------------------------------
+// Metadata processing
+
+#ifndef JPEG_APP1
+# define JPEG_APP1 (JPEG_APP0 + 1)
+#endif
+#ifndef JPEG_APP2
+# define JPEG_APP2 (JPEG_APP0 + 2)
+#endif
+
+typedef struct {
+  const uint8_t* data;
+  size_t data_length;
+  int seq;  // this segment's sequence number [1, 255] for use in reassembly.
+} ICCPSegment;
+
+static void SaveMetadataMarkers(j_decompress_ptr dinfo) {
+  const unsigned int max_marker_length = 0xffff;
+  jpeg_save_markers(dinfo, JPEG_APP1, max_marker_length);  // Exif/XMP
+  jpeg_save_markers(dinfo, JPEG_APP2, max_marker_length);  // ICC profile
+}
+
+static int CompareICCPSegments(const void* a, const void* b) {
+  const ICCPSegment* s1 = (const ICCPSegment*)a;
+  const ICCPSegment* s2 = (const ICCPSegment*)b;
+  return s1->seq - s2->seq;
+}
+
+// Extract ICC profile segments from the marker list in 'dinfo', reassembling
+// and storing them in 'iccp'.
+// Returns true on success and false for memory errors and corrupt profiles.
+static int StoreICCP(j_decompress_ptr dinfo, MetadataPayload* const iccp) {
+  // ICC.1:2010-12 (4.3.0.0) Annex B.4 Embedding ICC Profiles in JPEG files
+  static const char kICCPSignature[] = "ICC_PROFILE";
+  static const size_t kICCPSignatureLength = 12;  // signature includes '\0'
+  static const size_t kICCPSkipLength = 14;  // signature + seq & count
+  int expected_count = 0;
+  int actual_count = 0;
+  int seq_max = 0;
+  size_t total_size = 0;
+  ICCPSegment iccp_segments[255];
+  jpeg_saved_marker_ptr marker;
+
+  memset(iccp_segments, 0, sizeof(iccp_segments));
+  for (marker = dinfo->marker_list; marker != NULL; marker = marker->next) {
+    if (marker->marker == JPEG_APP2 &&
+        marker->data_length > kICCPSkipLength &&
+        !memcmp(marker->data, kICCPSignature, kICCPSignatureLength)) {
+      // ICC_PROFILE\0<seq><count>; 'seq' starts at 1.
+      const int seq = marker->data[kICCPSignatureLength];
+      const int count = marker->data[kICCPSignatureLength + 1];
+      const size_t segment_size = marker->data_length - kICCPSkipLength;
+      ICCPSegment* segment;
+
+      if (segment_size == 0 || count == 0 || seq == 0) {
+        fprintf(stderr, "[ICCP] size (%d) / count (%d) / sequence number (%d)"
+                        " cannot be 0!\n",
+                (int)segment_size, seq, count);
+        return 0;
+      }
+
+      if (expected_count == 0) {
+        expected_count = count;
+      } else if (expected_count != count) {
+        fprintf(stderr, "[ICCP] Inconsistent segment count (%d / %d)!\n",
+                expected_count, count);
+        return 0;
+      }
+
+      segment = iccp_segments + seq - 1;
+      if (segment->data_length != 0) {
+        fprintf(stderr, "[ICCP] Duplicate segment number (%d)!\n" , seq);
+        return 0;
+      }
+
+      segment->data = marker->data + kICCPSkipLength;
+      segment->data_length = segment_size;
+      segment->seq = seq;
+      total_size += segment_size;
+      if (seq > seq_max) seq_max = seq;
+      ++actual_count;
+    }
+  }
+
+  if (actual_count == 0) return 1;
+  if (seq_max != actual_count) {
+    fprintf(stderr, "[ICCP] Discontinuous segments, expected: %d actual: %d!\n",
+            actual_count, seq_max);
+    return 0;
+  }
+  if (expected_count != actual_count) {
+    fprintf(stderr, "[ICCP] Segment count: %d does not match expected: %d!\n",
+            actual_count, expected_count);
+    return 0;
+  }
+
+  // The segments may appear out of order in the file, sort them based on
+  // sequence number before assembling the payload.
+  qsort(iccp_segments, actual_count, sizeof(*iccp_segments),
+        CompareICCPSegments);
+
+  iccp->bytes = (uint8_t*)malloc(total_size);
+  if (iccp->bytes == NULL) return 0;
+  iccp->size = total_size;
+
+  {
+    int i;
+    size_t offset = 0;
+    for (i = 0; i < seq_max; ++i) {
+      memcpy(iccp->bytes + offset,
+             iccp_segments[i].data, iccp_segments[i].data_length);
+      offset += iccp_segments[i].data_length;
+    }
+  }
+  return 1;
+}
+
+// Returns true on success and false for memory errors and corrupt profiles.
+// The caller must use MetadataFree() on 'metadata' in all cases.
+static int ExtractMetadataFromJPEG(j_decompress_ptr dinfo,
+                                   Metadata* const metadata) {
+  static const struct {
+    int marker;
+    const char* signature;
+    size_t signature_length;
+    size_t storage_offset;
+  } kJPEGMetadataMap[] = {
+    // Exif 2.2 Section 4.7.2 Interoperability Structure of APP1 ...
+    { JPEG_APP1, "Exif\0",                        6, METADATA_OFFSET(exif) },
+    // XMP Specification Part 3 Section 3 Embedding XMP Metadata ... #JPEG
+    // TODO(jzern) Add support for 'ExtendedXMP'
+    { JPEG_APP1, "http://ns.adobe.com/xap/1.0/", 29, METADATA_OFFSET(xmp) },
+    { 0, NULL, 0, 0 },
+  };
+  jpeg_saved_marker_ptr marker;
+  // Treat ICC profiles separately as they may be segmented and out of order.
+  if (!StoreICCP(dinfo, &metadata->iccp)) return 0;
+
+  for (marker = dinfo->marker_list; marker != NULL; marker = marker->next) {
+    int i;
+    for (i = 0; kJPEGMetadataMap[i].marker != 0; ++i) {
+      if (marker->marker == kJPEGMetadataMap[i].marker &&
+          marker->data_length > kJPEGMetadataMap[i].signature_length &&
+          !memcmp(marker->data, kJPEGMetadataMap[i].signature,
+                  kJPEGMetadataMap[i].signature_length)) {
+        MetadataPayload* const payload =
+            (MetadataPayload*)((uint8_t*)metadata +
+                               kJPEGMetadataMap[i].storage_offset);
+
+        if (payload->bytes == NULL) {
+          const char* marker_data = (const char*)marker->data +
+                                    kJPEGMetadataMap[i].signature_length;
+          const size_t marker_data_length =
+              marker->data_length - kJPEGMetadataMap[i].signature_length;
+          if (!MetadataCopy(marker_data, marker_data_length, payload)) return 0;
+        } else {
+          fprintf(stderr, "Ignoring additional '%s' marker\n",
+                  kJPEGMetadataMap[i].signature);
+        }
+      }
+    }
+  }
+  return 1;
+}
+
+#undef JPEG_APP1
+#undef JPEG_APP2
+
+// -----------------------------------------------------------------------------
+// JPEG decoding
+
+struct my_error_mgr {
+  struct jpeg_error_mgr pub;
+  jmp_buf setjmp_buffer;
+};
+
+static void my_error_exit(j_common_ptr dinfo) {
+  struct my_error_mgr* myerr = (struct my_error_mgr*)dinfo->err;
+  fprintf(stderr, "libjpeg error: ");
+  dinfo->err->output_message(dinfo);
+  longjmp(myerr->setjmp_buffer, 1);
+}
+
+typedef struct {
+  struct jpeg_source_mgr pub;
+  const uint8_t* data;
+  size_t data_size;
+} JPEGReadContext;
+
+static void ContextInit(j_decompress_ptr cinfo) {
+  JPEGReadContext* const ctx = (JPEGReadContext*)cinfo->src;
+  ctx->pub.next_input_byte = ctx->data;
+  ctx->pub.bytes_in_buffer = ctx->data_size;
+}
+
+static boolean ContextFill(j_decompress_ptr cinfo) {
+  // we shouldn't get here.
+  ERREXIT(cinfo, JERR_FILE_READ);
+  return FALSE;
+}
+
+static void ContextSkip(j_decompress_ptr cinfo, long jump_size) {
+  JPEGReadContext* const ctx = (JPEGReadContext*)cinfo->src;
+  size_t jump = (size_t)jump_size;
+  if (jump > ctx->pub.bytes_in_buffer) {  // Don't overflow the buffer.
+    jump = ctx->pub.bytes_in_buffer;
+  }
+  ctx->pub.bytes_in_buffer -= jump;
+  ctx->pub.next_input_byte += jump;
+}
+
+static void ContextTerm(j_decompress_ptr cinfo) {
+  (void)cinfo;
+}
+
+static void ContextSetup(volatile struct jpeg_decompress_struct* const cinfo,
+                         JPEGReadContext* const ctx) {
+  cinfo->src = (struct jpeg_source_mgr*)ctx;
+  ctx->pub.init_source = ContextInit;
+  ctx->pub.fill_input_buffer = ContextFill;
+  ctx->pub.skip_input_data = ContextSkip;
+  ctx->pub.resync_to_restart = jpeg_resync_to_restart;
+  ctx->pub.term_source = ContextTerm;
+  ctx->pub.bytes_in_buffer = 0;
+  ctx->pub.next_input_byte = NULL;
+}
+
+int ReadJPEG(const uint8_t* const data, size_t data_size,
+             WebPPicture* const pic, int keep_alpha,
+             Metadata* const metadata) {
+  volatile int ok = 0;
+  int width, height;
+  int64_t stride;
+  volatile struct jpeg_decompress_struct dinfo;
+  struct my_error_mgr jerr;
+  uint8_t* volatile rgb = NULL;
+  JSAMPROW buffer[1];
+  JPEGReadContext ctx;
+
+  if (data == NULL || data_size == 0 || pic == NULL) return 0;
+
+  (void)keep_alpha;
+  memset(&ctx, 0, sizeof(ctx));
+  ctx.data = data;
+  ctx.data_size = data_size;
+
+  memset((j_decompress_ptr)&dinfo, 0, sizeof(dinfo));   // for setjmp safety
+  dinfo.err = jpeg_std_error(&jerr.pub);
+  jerr.pub.error_exit = my_error_exit;
+
+  if (setjmp(jerr.setjmp_buffer)) {
+ Error:
+    MetadataFree(metadata);
+    jpeg_destroy_decompress((j_decompress_ptr)&dinfo);
+    goto End;
+  }
+
+  jpeg_create_decompress((j_decompress_ptr)&dinfo);
+  ContextSetup(&dinfo, &ctx);
+  if (metadata != NULL) SaveMetadataMarkers((j_decompress_ptr)&dinfo);
+  jpeg_read_header((j_decompress_ptr)&dinfo, TRUE);
+
+  dinfo.out_color_space = JCS_RGB;
+  dinfo.do_fancy_upsampling = TRUE;
+
+  jpeg_start_decompress((j_decompress_ptr)&dinfo);
+
+  if (dinfo.output_components != 3) {
+    goto Error;
+  }
+
+  width = dinfo.output_width;
+  height = dinfo.output_height;
+  stride = (int64_t)dinfo.output_width * dinfo.output_components * sizeof(*rgb);
+
+  if (stride != (int)stride ||
+      !ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) {
+    goto Error;
+  }
+
+  rgb = (uint8_t*)malloc((size_t)stride * height);
+  if (rgb == NULL) {
+    goto Error;
+  }
+  buffer[0] = (JSAMPLE*)rgb;
+
+  while (dinfo.output_scanline < dinfo.output_height) {
+    if (jpeg_read_scanlines((j_decompress_ptr)&dinfo, buffer, 1) != 1) {
+      goto Error;
+    }
+    buffer[0] += stride;
+  }
+
+  if (metadata != NULL) {
+    ok = ExtractMetadataFromJPEG((j_decompress_ptr)&dinfo, metadata);
+    if (!ok) {
+      fprintf(stderr, "Error extracting JPEG metadata!\n");
+      goto Error;
+    }
+  }
+
+  jpeg_finish_decompress((j_decompress_ptr)&dinfo);
+  jpeg_destroy_decompress((j_decompress_ptr)&dinfo);
+
+  // WebP conversion.
+  pic->width = width;
+  pic->height = height;
+  ok = WebPPictureImportRGB(pic, rgb, (int)stride);
+  if (!ok) {
+    pic->width = 0;   // WebPPictureImportRGB() barely touches 'pic' on failure.
+    pic->height = 0;  // Just reset dimensions but keep any 'custom_ptr' etc.
+    MetadataFree(metadata);  // In case the caller forgets to free it on error.
+  }
+
+ End:
+  free(rgb);
+  return ok;
+}
+#else  // !WEBP_HAVE_JPEG
+int ReadJPEG(const uint8_t* const data, size_t data_size,
+             struct WebPPicture* const pic, int keep_alpha,
+             struct Metadata* const metadata) {
+  (void)data;
+  (void)data_size;
+  (void)pic;
+  (void)keep_alpha;
+  (void)metadata;
+  fprintf(stderr, "JPEG support not compiled. Please install the libjpeg "
+          "development package before building.\n");
+  return 0;
+}
+#endif  // WEBP_HAVE_JPEG
+
+// -----------------------------------------------------------------------------

imageio/jpegdec.h

@@ -0,0 +1,37 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// JPEG decode.
+
+#ifndef WEBP_IMAGEIO_JPEGDEC_H_
+#define WEBP_IMAGEIO_JPEGDEC_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+// Reads a JPEG from 'data', returning the decoded output in 'pic'.
+// The output is RGB or YUV depending on pic->use_argb value.
+// Returns true on success.
+// 'keep_alpha' has no effect, but is kept for coherence with other signatures
+// for image readers.
+int ReadJPEG(const uint8_t* const data, size_t data_size,
+             struct WebPPicture* const pic, int keep_alpha,
+             struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_JPEGDEC_H_

imageio/metadata.c

@@ -0,0 +1,49 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Metadata types and functions.
+//
+
+#include "./metadata.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/types.h"
+
+void MetadataInit(Metadata* const metadata) {
+  if (metadata == NULL) return;
+  memset(metadata, 0, sizeof(*metadata));
+}
+
+void MetadataPayloadDelete(MetadataPayload* const payload) {
+  if (payload == NULL) return;
+  free(payload->bytes);
+  payload->bytes = NULL;
+  payload->size = 0;
+}
+
+void MetadataFree(Metadata* const metadata) {
+  if (metadata == NULL) return;
+  MetadataPayloadDelete(&metadata->exif);
+  MetadataPayloadDelete(&metadata->iccp);
+  MetadataPayloadDelete(&metadata->xmp);
+}
+
+int MetadataCopy(const char* metadata, size_t metadata_len,
+                 MetadataPayload* const payload) {
+  if (metadata == NULL || metadata_len == 0 || payload == NULL) return 0;
+  payload->bytes = (uint8_t*)malloc(metadata_len);
+  if (payload->bytes == NULL) return 0;
+  payload->size = metadata_len;
+  memcpy(payload->bytes, metadata, metadata_len);
+  return 1;
+}
+
+// -----------------------------------------------------------------------------

imageio/metadata.h

@@ -0,0 +1,47 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Metadata types and functions.
+//
+
+#ifndef WEBP_IMAGEIO_METADATA_H_
+#define WEBP_IMAGEIO_METADATA_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct MetadataPayload {
+  uint8_t* bytes;
+  size_t size;
+} MetadataPayload;
+
+typedef struct Metadata {
+  MetadataPayload exif;
+  MetadataPayload iccp;
+  MetadataPayload xmp;
+} Metadata;
+
+#define METADATA_OFFSET(x) offsetof(Metadata, x)
+
+void MetadataInit(Metadata* const metadata);
+void MetadataPayloadDelete(MetadataPayload* const payload);
+void MetadataFree(Metadata* const metadata);
+
+// Stores 'metadata' to 'payload->bytes', returns false on allocation error.
+int MetadataCopy(const char* metadata, size_t metadata_len,
+                 MetadataPayload* const payload);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_METADATA_H_

imageio/pngdec.c

@@ -0,0 +1,374 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// PNG decode.
+
+#include "./pngdec.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include <stdio.h>
+
+#ifdef WEBP_HAVE_PNG
+#ifndef PNG_USER_MEM_SUPPORTED
+#define PNG_USER_MEM_SUPPORTED  // for png_create_read_struct_2
+#endif
+#include <png.h>
+#include <setjmp.h>   // note: this must be included *after* png.h
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/encode.h"
+#include "./imageio_util.h"
+#include "./metadata.h"
+
+#define LOCAL_PNG_VERSION ((PNG_LIBPNG_VER_MAJOR << 8) | PNG_LIBPNG_VER_MINOR)
+#define LOCAL_PNG_PREREQ(maj, min) \
+   (LOCAL_PNG_VERSION >= (((maj) << 8) | (min)))
+
+static void PNGAPI error_function(png_structp png, png_const_charp error) {
+  if (error != NULL) fprintf(stderr, "libpng error: %s\n", error);
+  longjmp(png_jmpbuf(png), 1);
+}
+
+#if LOCAL_PNG_PREREQ(1,4)
+typedef png_alloc_size_t LocalPngAllocSize;
+#else
+typedef png_size_t LocalPngAllocSize;
+#endif
+
+static png_voidp MallocFunc(png_structp png_ptr, LocalPngAllocSize size) {
+  (void)png_ptr;
+  if (size != (size_t)size) return NULL;
+  if (!ImgIoUtilCheckSizeArgumentsOverflow(size, 1)) return NULL;
+  return (png_voidp)malloc((size_t)size);
+}
+
+static void FreeFunc(png_structp png_ptr, png_voidp ptr) {
+  (void)png_ptr;
+  free(ptr);
+}
+
+// Converts the NULL terminated 'hexstring' which contains 2-byte character
+// representations of hex values to raw data.
+// 'hexstring' may contain values consisting of [A-F][a-f][0-9] in pairs,
+// e.g., 7af2..., separated by any number of newlines.
+// 'expected_length' is the anticipated processed size.
+// On success the raw buffer is returned with its length equivalent to
+// 'expected_length'. NULL is returned if the processed length is less than
+// 'expected_length' or any character aside from those above is encountered.
+// The returned buffer must be freed by the caller.
+static uint8_t* HexStringToBytes(const char* hexstring,
+                                 size_t expected_length) {
+  const char* src = hexstring;
+  size_t actual_length = 0;
+  uint8_t* const raw_data = (uint8_t*)malloc(expected_length);
+  uint8_t* dst;
+
+  if (raw_data == NULL) return NULL;
+
+  for (dst = raw_data; actual_length < expected_length && *src != '\0'; ++src) {
+    char* end;
+    char val[3];
+    if (*src == '\n') continue;
+    val[0] = *src++;
+    val[1] = *src;
+    val[2] = '\0';
+    *dst++ = (uint8_t)strtol(val, &end, 16);
+    if (end != val + 2) break;
+    ++actual_length;
+  }
+
+  if (actual_length != expected_length) {
+    free(raw_data);
+    return NULL;
+  }
+  return raw_data;
+}
+
+static int ProcessRawProfile(const char* profile, size_t profile_len,
+                             MetadataPayload* const payload) {
+  const char* src = profile;
+  char* end;
+  int expected_length;
+
+  if (profile == NULL || profile_len == 0) return 0;
+
+  // ImageMagick formats 'raw profiles' as
+  // '\n<name>\n<length>(%8lu)\n<hex payload>\n'.
+  if (*src != '\n') {
+    fprintf(stderr, "Malformed raw profile, expected '\\n' got '\\x%.2X'\n",
+            *src);
+    return 0;
+  }
+  ++src;
+  // skip the profile name and extract the length.
+  while (*src != '\0' && *src++ != '\n') {}
+  expected_length = (int)strtol(src, &end, 10);
+  if (*end != '\n') {
+    fprintf(stderr, "Malformed raw profile, expected '\\n' got '\\x%.2X'\n",
+            *end);
+    return 0;
+  }
+  ++end;
+
+  // 'end' now points to the profile payload.
+  payload->bytes = HexStringToBytes(end, expected_length);
+  if (payload->bytes == NULL) return 0;
+  payload->size = expected_length;
+  return 1;
+}
+
+static const struct {
+  const char* name;
+  int (*process)(const char* profile, size_t profile_len,
+                 MetadataPayload* const payload);
+  size_t storage_offset;
+} kPNGMetadataMap[] = {
+  // https://exiftool.org/TagNames/PNG.html#TextualData
+  // See also: ExifTool on CPAN.
+  { "Raw profile type exif", ProcessRawProfile, METADATA_OFFSET(exif) },
+  { "Raw profile type xmp",  ProcessRawProfile, METADATA_OFFSET(xmp) },
+  // Exiftool puts exif data in APP1 chunk, too.
+  { "Raw profile type APP1", ProcessRawProfile, METADATA_OFFSET(exif) },
+  // XMP Specification Part 3, Section 3 #PNG
+  { "XML:com.adobe.xmp",     MetadataCopy,      METADATA_OFFSET(xmp) },
+  { NULL, NULL, 0 },
+};
+
+// Looks for metadata at both the beginning and end of the PNG file, giving
+// preference to the head.
+// Returns true on success. The caller must use MetadataFree() on 'metadata' in
+// all cases.
+static int ExtractMetadataFromPNG(png_structp png,
+                                  png_infop const head_info,
+                                  png_infop const end_info,
+                                  Metadata* const metadata) {
+  int p;
+
+  for (p = 0; p < 2; ++p)  {
+    png_infop const info = (p == 0) ? head_info : end_info;
+    png_textp text = NULL;
+    const png_uint_32 num = png_get_text(png, info, &text, NULL);
+    png_uint_32 i;
+    // Look for EXIF / XMP metadata.
+    for (i = 0; i < num; ++i, ++text) {
+      int j;
+      for (j = 0; kPNGMetadataMap[j].name != NULL; ++j) {
+        if (!strcmp(text->key, kPNGMetadataMap[j].name)) {
+          MetadataPayload* const payload =
+              (MetadataPayload*)((uint8_t*)metadata +
+                                 kPNGMetadataMap[j].storage_offset);
+          png_size_t text_length;
+          switch (text->compression) {
+#ifdef PNG_iTXt_SUPPORTED
+            case PNG_ITXT_COMPRESSION_NONE:
+            case PNG_ITXT_COMPRESSION_zTXt:
+              text_length = text->itxt_length;
+              break;
+#endif
+            case PNG_TEXT_COMPRESSION_NONE:
+            case PNG_TEXT_COMPRESSION_zTXt:
+            default:
+              text_length = text->text_length;
+              break;
+          }
+          if (payload->bytes != NULL) {
+            fprintf(stderr, "Ignoring additional '%s'\n", text->key);
+          } else if (!kPNGMetadataMap[j].process(text->text, text_length,
+                                                 payload)) {
+            fprintf(stderr, "Failed to process: '%s'\n", text->key);
+            return 0;
+          }
+          break;
+        }
+      }
+    }
+    // Look for an ICC profile.
+    {
+      png_charp name;
+      int comp_type;
+#if LOCAL_PNG_PREREQ(1,5)
+      png_bytep profile;
+#else
+      png_charp profile;
+#endif
+      png_uint_32 len;
+
+      if (png_get_iCCP(png, info,
+                       &name, &comp_type, &profile, &len) == PNG_INFO_iCCP) {
+        if (!MetadataCopy((const char*)profile, len, &metadata->iccp)) return 0;
+      }
+    }
+  }
+  return 1;
+}
+
+typedef struct {
+  const uint8_t* data;
+  size_t data_size;
+  png_size_t offset;
+} PNGReadContext;
+
+static void ReadFunc(png_structp png_ptr, png_bytep data, png_size_t length) {
+  PNGReadContext* const ctx = (PNGReadContext*)png_get_io_ptr(png_ptr);
+  if (ctx->data_size - ctx->offset < length) {
+    png_error(png_ptr, "ReadFunc: invalid read length (overflow)!");
+  }
+  memcpy(data, ctx->data + ctx->offset, length);
+  ctx->offset += length;
+}
+
+int ReadPNG(const uint8_t* const data, size_t data_size,
+            struct WebPPicture* const pic,
+            int keep_alpha, struct Metadata* const metadata) {
+  volatile png_structp png = NULL;
+  volatile png_infop info = NULL;
+  volatile png_infop end_info = NULL;
+  PNGReadContext context = { NULL, 0, 0 };
+  int color_type, bit_depth, interlaced;
+  int num_channels;
+  int num_passes;
+  int p;
+  volatile int ok = 0;
+  png_uint_32 width, height, y;
+  int64_t stride;
+  uint8_t* volatile rgb = NULL;
+
+  if (data == NULL || data_size == 0 || pic == NULL) return 0;
+
+  context.data = data;
+  context.data_size = data_size;
+
+  png = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL,
+                                 NULL, MallocFunc, FreeFunc);
+  if (png == NULL) goto End;
+
+  png_set_error_fn(png, 0, error_function, NULL);
+  if (setjmp(png_jmpbuf(png))) {
+ Error:
+    MetadataFree(metadata);
+    goto End;
+  }
+
+#if LOCAL_PNG_PREREQ(1,5) || \
+    (LOCAL_PNG_PREREQ(1,4) && PNG_LIBPNG_VER_RELEASE >= 1)
+  // If it looks like the bitstream is going to need more memory than libpng's
+  // internal limit (default: 8M), try to (reasonably) raise it.
+  if (data_size > png_get_chunk_malloc_max(png) && data_size < (1u << 24)) {
+    png_set_chunk_malloc_max(png, data_size);
+  }
+#endif
+
+  info = png_create_info_struct(png);
+  if (info == NULL) goto Error;
+  end_info = png_create_info_struct(png);
+  if (end_info == NULL) goto Error;
+
+  png_set_read_fn(png, &context, ReadFunc);
+  png_read_info(png, info);
+  if (!png_get_IHDR(png, info,
+                    &width, &height, &bit_depth, &color_type, &interlaced,
+                    NULL, NULL)) goto Error;
+
+  png_set_strip_16(png);
+  png_set_packing(png);
+  if (color_type == PNG_COLOR_TYPE_PALETTE) {
+    png_set_palette_to_rgb(png);
+  }
+  if (color_type == PNG_COLOR_TYPE_GRAY ||
+      color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
+    if (bit_depth < 8) {
+      png_set_expand_gray_1_2_4_to_8(png);
+    }
+    png_set_gray_to_rgb(png);
+  }
+  if (png_get_valid(png, info, PNG_INFO_tRNS)) {
+    png_set_tRNS_to_alpha(png);
+  }
+
+  // Apply gamma correction if needed.
+  {
+    double image_gamma = 1 / 2.2, screen_gamma = 2.2;
+    int srgb_intent;
+    if (png_get_sRGB(png, info, &srgb_intent) ||
+        png_get_gAMA(png, info, &image_gamma)) {
+      png_set_gamma(png, screen_gamma, image_gamma);
+    }
+  }
+
+  if (!keep_alpha) {
+    png_set_strip_alpha(png);
+  }
+
+  num_passes = png_set_interlace_handling(png);
+  png_read_update_info(png, info);
+
+  num_channels = png_get_channels(png, info);
+  if (num_channels != 3 && num_channels != 4) {
+    goto Error;
+  }
+  stride = (int64_t)num_channels * width * sizeof(*rgb);
+  if (stride != (int)stride ||
+      !ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) {
+    goto Error;
+  }
+
+  rgb = (uint8_t*)malloc((size_t)stride * height);
+  if (rgb == NULL) goto Error;
+  for (p = 0; p < num_passes; ++p) {
+    png_bytep row = rgb;
+    for (y = 0; y < height; ++y) {
+      png_read_rows(png, &row, NULL, 1);
+      row += stride;
+    }
+  }
+  png_read_end(png, end_info);
+
+  if (metadata != NULL &&
+      !ExtractMetadataFromPNG(png, info, end_info, metadata)) {
+    fprintf(stderr, "Error extracting PNG metadata!\n");
+    goto Error;
+  }
+
+  pic->width = (int)width;
+  pic->height = (int)height;
+  ok = (num_channels == 4) ? WebPPictureImportRGBA(pic, rgb, (int)stride)
+                           : WebPPictureImportRGB(pic, rgb, (int)stride);
+
+  if (!ok) {
+    goto Error;
+  }
+
+ End:
+  if (png != NULL) {
+    png_destroy_read_struct((png_structpp)&png,
+                            (png_infopp)&info, (png_infopp)&end_info);
+  }
+  free(rgb);
+  return ok;
+}
+#else  // !WEBP_HAVE_PNG
+int ReadPNG(const uint8_t* const data, size_t data_size,
+            struct WebPPicture* const pic,
+            int keep_alpha, struct Metadata* const metadata) {
+  (void)data;
+  (void)data_size;
+  (void)pic;
+  (void)keep_alpha;
+  (void)metadata;
+  fprintf(stderr, "PNG support not compiled. Please install the libpng "
+          "development package before building.\n");
+  return 0;
+}
+#endif  // WEBP_HAVE_PNG
+
+// -----------------------------------------------------------------------------

imageio/pngdec.h

@@ -0,0 +1,37 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// PNG decode.
+
+#ifndef WEBP_IMAGEIO_PNGDEC_H_
+#define WEBP_IMAGEIO_PNGDEC_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+// Reads a PNG from 'data', returning the decoded output in 'pic'.
+// Output is RGBA or YUVA, depending on pic->use_argb value.
+// If 'keep_alpha' is true and the PNG has an alpha channel, the output is RGBA
+// or YUVA. Otherwise, alpha channel is dropped and output is RGB or YUV.
+// Returns true on success.
+int ReadPNG(const uint8_t* const data, size_t data_size,
+            struct WebPPicture* const pic,
+            int keep_alpha, struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_PNGDEC_H_

imageio/pnmdec.c

@@ -0,0 +1,301 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// (limited) PNM decoder
+
+#include "./pnmdec.h"
+
+#include <assert.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/encode.h"
+#include "./imageio_util.h"
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf
+#endif
+
+typedef enum {
+  WIDTH_FLAG      = 1 << 0,
+  HEIGHT_FLAG     = 1 << 1,
+  DEPTH_FLAG      = 1 << 2,
+  MAXVAL_FLAG     = 1 << 3,
+  TUPLE_FLAG      = 1 << 4,
+  ALL_NEEDED_FLAGS = WIDTH_FLAG | HEIGHT_FLAG | DEPTH_FLAG | MAXVAL_FLAG
+} PNMFlags;
+
+typedef struct {
+  const uint8_t* data;
+  size_t data_size;
+  int width, height;
+  int bytes_per_px;
+  int depth;          // 1 (grayscale), 2 (grayscale + alpha), 3 (rgb), 4 (rgba)
+  int max_value;
+  int type;           // 5, 6 or 7
+  int seen_flags;
+} PNMInfo;
+
+// -----------------------------------------------------------------------------
+// PNM decoding
+
+#define MAX_LINE_SIZE 1024
+static const size_t kMinPNMHeaderSize = 3;
+
+static size_t ReadLine(const uint8_t* const data, size_t off, size_t data_size,
+                       char out[MAX_LINE_SIZE + 1], size_t* const out_size) {
+  size_t i = 0;
+  *out_size = 0;
+ redo:
+  for (i = 0; i < MAX_LINE_SIZE && off < data_size; ++i) {
+    out[i] = data[off++];
+    if (out[i] == '\n') break;
+  }
+  if (off < data_size) {
+    if (i == 0) goto redo;         // empty line
+    if (out[0] == '#') goto redo;  // skip comment
+  }
+  out[i] = 0;   // safety sentinel
+  *out_size = i;
+  return off;
+}
+
+static size_t FlagError(const char flag[]) {
+  fprintf(stderr, "PAM header error: flags '%s' already seen.\n", flag);
+  return 0;
+}
+
+// inspired from http://netpbm.sourceforge.net/doc/pam.html
+static size_t ReadPAMFields(PNMInfo* const info, size_t off) {
+  char out[MAX_LINE_SIZE + 1];
+  size_t out_size;
+  int tmp;
+  int expected_depth = -1;
+  assert(info != NULL);
+  while (1) {
+    off = ReadLine(info->data, off, info->data_size, out, &out_size);
+    if (off == 0) return 0;
+    if (sscanf(out, "WIDTH %d", &tmp) == 1) {
+      if (info->seen_flags & WIDTH_FLAG) return FlagError("WIDTH");
+      info->seen_flags |= WIDTH_FLAG;
+      info->width = tmp;
+    } else if (sscanf(out, "HEIGHT %d", &tmp) == 1) {
+      if (info->seen_flags & HEIGHT_FLAG) return FlagError("HEIGHT");
+      info->seen_flags |= HEIGHT_FLAG;
+      info->height = tmp;
+    } else if (sscanf(out, "DEPTH %d", &tmp) == 1) {
+      if (info->seen_flags & DEPTH_FLAG) return FlagError("DEPTH");
+      info->seen_flags |= DEPTH_FLAG;
+      info->depth = tmp;
+    } else if (sscanf(out, "MAXVAL %d", &tmp) == 1) {
+      if (info->seen_flags & MAXVAL_FLAG) return FlagError("MAXVAL");
+      info->seen_flags |= MAXVAL_FLAG;
+      info->max_value = tmp;
+    } else if (!strcmp(out, "TUPLTYPE RGB_ALPHA")) {
+      expected_depth = 4;
+      info->seen_flags |= TUPLE_FLAG;
+    } else if (!strcmp(out, "TUPLTYPE RGB")) {
+      expected_depth = 3;
+      info->seen_flags |= TUPLE_FLAG;
+    } else if (!strcmp(out, "TUPLTYPE GRAYSCALE_ALPHA")) {
+      expected_depth = 2;
+      info->seen_flags |= TUPLE_FLAG;
+    } else if (!strcmp(out, "TUPLTYPE GRAYSCALE")) {
+      expected_depth = 1;
+      info->seen_flags |= TUPLE_FLAG;
+    } else if (!strcmp(out, "ENDHDR")) {
+      break;
+    } else {
+      static const char kEllipsis[] = " ...";
+      const size_t kLen = strlen(kEllipsis) + 1;  // +1 = trailing \0
+      int i;
+      if (out_size > 20) snprintf(out + 20 - kLen, kLen, kEllipsis);
+      for (i = 0; i < (int)strlen(out); ++i) {
+        // isprint() might trigger a "char-subscripts" warning if given a char.
+        if (!isprint((int)out[i])) out[i] = ' ';
+      }
+      fprintf(stderr, "PAM header error: unrecognized entry [%s]\n", out);
+      return 0;
+    }
+  }
+  if (!(info->seen_flags & ALL_NEEDED_FLAGS)) {
+    fprintf(stderr, "PAM header error: missing tags%s%s%s%s\n",
+            (info->seen_flags & WIDTH_FLAG) ? "" : " WIDTH",
+            (info->seen_flags & HEIGHT_FLAG) ? "" : " HEIGHT",
+            (info->seen_flags & DEPTH_FLAG) ? "" : " DEPTH",
+            (info->seen_flags & MAXVAL_FLAG) ? "" : " MAXVAL");
+    return 0;
+  }
+  if (expected_depth != -1 && info->depth != expected_depth) {
+    fprintf(stderr, "PAM header error: expected DEPTH %d but got DEPTH %d\n",
+            expected_depth, info->depth);
+    return 0;
+  }
+  return off;
+}
+
+static size_t ReadHeader(PNMInfo* const info) {
+  size_t off = 0;
+  char out[MAX_LINE_SIZE + 1];
+  size_t out_size;
+  if (info == NULL) return 0;
+  if (info->data == NULL || info->data_size < kMinPNMHeaderSize) return 0;
+
+  info->width = info->height = 0;
+  info->type = -1;
+  info->seen_flags = 0;
+  info->bytes_per_px = 0;
+  info->depth = 0;
+  info->max_value = 0;
+
+  off = ReadLine(info->data, off, info->data_size, out, &out_size);
+  if (off == 0 || sscanf(out, "P%d", &info->type) != 1) return 0;
+  if (info->type == 7) {
+    off = ReadPAMFields(info, off);
+  } else {
+    off = ReadLine(info->data, off, info->data_size, out, &out_size);
+    if (off == 0 || sscanf(out, "%d %d", &info->width, &info->height) != 2) {
+      return 0;
+    }
+    off = ReadLine(info->data, off, info->data_size, out, &out_size);
+    if (off == 0 || sscanf(out, "%d", &info->max_value) != 1) return 0;
+
+    // finish initializing missing fields
+    info->depth = (info->type == 5) ? 1 : 3;
+  }
+  // perform some basic numerical validation
+  if (info->width <= 0 || info->height <= 0 ||
+      info->type <= 0 || info->type >= 9 ||
+      info->depth <= 0 || info->depth > 4 ||
+      info->max_value <= 0 || info->max_value >= 65536) {
+    return 0;
+  }
+  info->bytes_per_px = info->depth * (info->max_value > 255 ? 2 : 1);
+  return off;
+}
+
+int ReadPNM(const uint8_t* const data, size_t data_size,
+            WebPPicture* const pic, int keep_alpha,
+            struct Metadata* const metadata) {
+  int ok = 0;
+  int i, j;
+  uint64_t stride, pixel_bytes, sample_size, depth;
+  uint8_t* rgb = NULL, *tmp_rgb;
+  size_t offset;
+  PNMInfo info;
+
+  info.data = data;
+  info.data_size = data_size;
+  offset = ReadHeader(&info);
+  if (offset == 0) {
+    fprintf(stderr, "Error parsing PNM header.\n");
+    goto End;
+  }
+
+  if (info.type < 5 || info.type > 7) {
+    fprintf(stderr, "Unsupported P%d PNM format.\n", info.type);
+    goto End;
+  }
+
+  // Some basic validations.
+  if (pic == NULL) goto End;
+  if (info.width > WEBP_MAX_DIMENSION || info.height > WEBP_MAX_DIMENSION) {
+    fprintf(stderr, "Invalid %dx%d dimension for PNM\n",
+                    info.width, info.height);
+    goto End;
+  }
+
+  pixel_bytes = (uint64_t)info.width * info.height * info.bytes_per_px;
+  if (data_size < offset + pixel_bytes) {
+    fprintf(stderr, "Truncated PNM file (P%d).\n", info.type);
+    goto End;
+  }
+  sample_size = (info.max_value > 255) ? 2 : 1;
+  // final depth
+  depth = (info.depth == 1 || info.depth == 3 || !keep_alpha) ? 3 : 4;
+  stride = depth * info.width;
+  if (stride != (size_t)stride ||
+      !ImgIoUtilCheckSizeArgumentsOverflow(stride, info.height)) {
+    goto End;
+  }
+
+  rgb = (uint8_t*)malloc((size_t)stride * info.height);
+  if (rgb == NULL) goto End;
+
+  // Convert input.
+  // We only optimize for the sample_size=1, max_value=255, depth=1 case.
+  tmp_rgb = rgb;
+  for (j = 0; j < info.height; ++j) {
+    const uint8_t* in = data + offset;
+    offset += info.bytes_per_px * info.width;
+    assert(offset <= data_size);
+    if (info.max_value == 255 && info.depth >= 3) {
+      // RGB or RGBA
+      if (info.depth == 3 || keep_alpha) {
+        memcpy(tmp_rgb, in, info.depth * info.width * sizeof(*in));
+      } else {
+        assert(info.depth == 4 && !keep_alpha);
+        for (i = 0; i < info.width; ++i) {
+          tmp_rgb[3 * i + 0] = in[4 * i + 0];
+          tmp_rgb[3 * i + 1] = in[4 * i + 1];
+          tmp_rgb[3 * i + 2] = in[4 * i + 2];
+        }
+      }
+    } else {
+      // Unoptimized case, we need to handle non-trivial operations:
+      //   * convert 16b to 8b (if max_value > 255)
+      //   * rescale to [0..255] range (if max_value != 255)
+      //   * drop the alpha channel (if keep_alpha is false)
+      const uint32_t round = info.max_value / 2;
+      int k = 0;
+      for (i = 0; i < info.width * info.depth; ++i) {
+        uint32_t v = (sample_size == 2) ? 256u * in[2 * i + 0] + in[2 * i + 1]
+                   : in[i];
+        if (info.max_value != 255) v = (v * 255u + round) / info.max_value;
+        if (v > 255u) v = 255u;
+        if (info.depth > 2) {
+          if (!keep_alpha && info.depth == 4 && (i % 4) == 3) {
+            // skip alpha
+          } else {
+            tmp_rgb[k] = v;
+            k += 1;
+          }
+        } else if (info.depth == 1 || (i % 2) == 0) {
+          tmp_rgb[k + 0] = tmp_rgb[k + 1] = tmp_rgb[k + 2] = v;
+          k += 3;
+        } else if (keep_alpha && info.depth == 2) {
+          tmp_rgb[k] = v;
+          k += 1;
+        } else {
+          // skip alpha
+        }
+      }
+    }
+    tmp_rgb += stride;
+  }
+
+  // WebP conversion.
+  pic->width = info.width;
+  pic->height = info.height;
+  ok = (depth == 4) ? WebPPictureImportRGBA(pic, rgb, (int)stride)
+                    : WebPPictureImportRGB(pic, rgb, (int)stride);
+  if (!ok) goto End;
+
+  ok = 1;
+ End:
+  free((void*)rgb);
+
+  (void)metadata;
+  (void)keep_alpha;
+  return ok;
+}
+
+// -----------------------------------------------------------------------------

imageio/pnmdec.h

@@ -0,0 +1,37 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// partial PNM format decoder (ppm/pgm)
+
+#ifndef WEBP_IMAGEIO_PNMDEC_H_
+#define WEBP_IMAGEIO_PNMDEC_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+// Reads a PNM file from 'data', returning the decoded output in 'pic'.
+// The output is RGB or YUV depending on pic->use_argb value.
+// Returns true on success.
+// 'metadata' has no effect, but is kept for coherence with other signatures
+// for image readers.
+int ReadPNM(const uint8_t* const data, size_t data_size,
+            struct WebPPicture* const pic, int keep_alpha,
+            struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_PNMDEC_H_

imageio/tiffdec.c

@@ -0,0 +1,293 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// TIFF decode.
+
+#include "./tiffdec.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+
+#ifdef WEBP_HAVE_TIFF
+#include <tiffio.h>
+
+#include "webp/encode.h"
+#include "./imageio_util.h"
+#include "./metadata.h"
+
+static const struct {
+  ttag_t tag;
+  size_t storage_offset;
+} kTIFFMetadataMap[] = {
+  { TIFFTAG_ICCPROFILE, METADATA_OFFSET(iccp) },
+  { TIFFTAG_XMLPACKET,  METADATA_OFFSET(xmp) },
+  { 0, 0 },
+};
+
+// Returns true on success. The caller must use MetadataFree() on 'metadata' in
+// all cases.
+static int ExtractMetadataFromTIFF(TIFF* const tif, Metadata* const metadata) {
+  int i;
+  toff_t exif_ifd_offset;
+
+  for (i = 0; kTIFFMetadataMap[i].tag != 0; ++i) {
+    MetadataPayload* const payload =
+        (MetadataPayload*)((uint8_t*)metadata +
+                           kTIFFMetadataMap[i].storage_offset);
+    void* tag_data;
+    uint32_t tag_data_len;
+
+    if (TIFFGetField(tif, kTIFFMetadataMap[i].tag, &tag_data_len, &tag_data) &&
+        !MetadataCopy((const char*)tag_data, tag_data_len, payload)) {
+      return 0;
+    }
+  }
+
+  // TODO(jzern): To extract the raw EXIF directory some parsing of it would be
+  // necessary to determine the overall size. In addition, value offsets in
+  // individual directory entries may need to be updated as, depending on the
+  // type, they are file based.
+  // Exif 2.2 Section 4.6.2 Tag Structure
+  // TIFF Revision 6.0 Part 1 Section 2 TIFF Structure #Image File Directory
+  if (TIFFGetField(tif, TIFFTAG_EXIFIFD, &exif_ifd_offset)) {
+    fprintf(stderr, "Warning: EXIF extraction from TIFF is unsupported.\n");
+  }
+  return 1;
+}
+
+// Ad-hoc structure to supply read-from-memory functionalities.
+typedef struct {
+  const uint8_t* data;
+  toff_t size;
+  toff_t pos;
+} MyData;
+
+static int MyClose(thandle_t opaque) {
+  (void)opaque;
+  return 0;
+}
+
+static toff_t MySize(thandle_t opaque) {
+  const MyData* const my_data = (MyData*)opaque;
+  return my_data->size;
+}
+
+static toff_t MySeek(thandle_t opaque, toff_t offset, int whence) {
+  MyData* const my_data = (MyData*)opaque;
+  offset += (whence == SEEK_CUR) ? my_data->pos
+          : (whence == SEEK_SET) ? 0
+          : my_data->size;
+  if (offset > my_data->size) return (toff_t)-1;
+  my_data->pos = offset;
+  return offset;
+}
+
+static int MyMapFile(thandle_t opaque, void** base, toff_t* size) {
+  (void)opaque;
+  (void)base;
+  (void)size;
+  return 0;
+}
+static void MyUnmapFile(thandle_t opaque, void* base, toff_t size) {
+  (void)opaque;
+  (void)base;
+  (void)size;
+}
+
+static tsize_t MyRead(thandle_t opaque, void* dst, tsize_t size) {
+  MyData* const my_data = (MyData*)opaque;
+  if (my_data->pos + size > my_data->size) {
+    size = (tsize_t)(my_data->size - my_data->pos);
+  }
+  if (size > 0) {
+    memcpy(dst, my_data->data + my_data->pos, size);
+    my_data->pos += size;
+  }
+  return size;
+}
+
+// Unmultiply Argb data. Taken from dsp/alpha_processing
+// (we don't want to force a dependency to a libdspdec library).
+#define MFIX 24    // 24bit fixed-point arithmetic
+#define HALF ((1u << MFIX) >> 1)
+
+static uint32_t Unmult(uint8_t x, uint32_t mult) {
+  const uint32_t v = (x * mult + HALF) >> MFIX;
+  return (v > 255u) ? 255u : v;
+}
+
+static WEBP_INLINE uint32_t GetScale(uint32_t a) {
+  return (255u << MFIX) / a;
+}
+
+#undef MFIX
+#undef HALF
+
+static void MultARGBRow(uint8_t* ptr, int width) {
+  int x;
+  for (x = 0; x < width; ++x, ptr += 4) {
+    const uint32_t alpha = ptr[3];
+    if (alpha < 255) {
+      if (alpha == 0) {   // alpha == 0
+        ptr[0] = ptr[1] = ptr[2] = 0;
+      } else {
+        const uint32_t scale = GetScale(alpha);
+        ptr[0] = Unmult(ptr[0], scale);
+        ptr[1] = Unmult(ptr[1], scale);
+        ptr[2] = Unmult(ptr[2], scale);
+      }
+    }
+  }
+}
+
+int ReadTIFF(const uint8_t* const data, size_t data_size,
+             WebPPicture* const pic, int keep_alpha,
+             Metadata* const metadata) {
+  MyData my_data = { data, (toff_t)data_size, 0 };
+  TIFF* tif;
+  uint32_t image_width, image_height, tile_width, tile_height;
+  uint64_t stride;
+  uint16_t samples_per_px = 0;
+  uint16_t extra_samples = 0;
+  uint16_t* extra_samples_ptr = NULL;
+  uint32_t* raster;
+  int64_t alloc_size;
+  int ok = 0;
+  tdir_t dircount;
+
+  if (data == NULL || data_size == 0 || data_size > INT_MAX || pic == NULL) {
+    return 0;
+  }
+
+  tif = TIFFClientOpen("Memory", "r", &my_data,
+                       MyRead, MyRead, MySeek, MyClose,
+                       MySize, MyMapFile, MyUnmapFile);
+  if (tif == NULL) {
+    fprintf(stderr, "Error! Cannot parse TIFF file\n");
+    return 0;
+  }
+
+  dircount = TIFFNumberOfDirectories(tif);
+  if (dircount > 1) {
+    fprintf(stderr, "Warning: multi-directory TIFF files are not supported.\n"
+                    "Only the first will be used, %d will be ignored.\n",
+                    dircount - 1);
+  }
+  if (!TIFFGetFieldDefaulted(tif, TIFFTAG_SAMPLESPERPIXEL, &samples_per_px)) {
+    fprintf(stderr, "Error! Cannot retrieve TIFF samples-per-pixel info.\n");
+    goto End;
+  }
+  if (!(samples_per_px == 1 || samples_per_px == 3 || samples_per_px == 4)) {
+    goto End;  // not supported
+  }
+
+  if (!(TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &image_width) &&
+        TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &image_height))) {
+    fprintf(stderr, "Error! Cannot retrieve TIFF image dimensions.\n");
+    goto End;
+  }
+  stride = (uint64_t)image_width * sizeof(*raster);
+  if (!ImgIoUtilCheckSizeArgumentsOverflow(stride, image_height)) {
+    fprintf(stderr, "Error! TIFF image dimension (%d x %d) is too large.\n",
+            image_width, image_height);
+    goto End;
+  }
+
+  // According to spec, a tile can be bigger than the image. However it should
+  // be a multiple of 16 and not way too large, so check that it's not more
+  // than twice the image size, for dimensions above some arbitrary minimum
+  // 32. We also check that they respect WebP's dimension and memory limit.
+  // Note that a tile can be 6byte/px in some cases. Here we assume
+  // 4byte/px with sizeof(*raster), to be conservative.
+  if (TIFFGetField(tif, TIFFTAG_TILEWIDTH, &tile_width) &&
+      TIFFGetField(tif, TIFFTAG_TILELENGTH, &tile_height)) {
+    if ((tile_width > 32 && tile_width / 2 > image_width) ||
+        (tile_height > 32 && tile_height / 2 > image_height) ||
+        !ImgIoUtilCheckSizeArgumentsOverflow(
+            (uint64_t)tile_width * sizeof(*raster), tile_height)) {
+      fprintf(stderr, "Error! TIFF tile dimension (%d x %d) is too large.\n",
+              tile_width, tile_height);
+      goto End;
+    }
+  }
+
+  if (samples_per_px > 3 && !TIFFGetField(tif, TIFFTAG_EXTRASAMPLES,
+                                          &extra_samples, &extra_samples_ptr)) {
+    fprintf(stderr, "Error! Cannot retrieve TIFF ExtraSamples info.\n");
+    goto End;
+  }
+
+  // _Tiffmalloc uses a signed type for size.
+  alloc_size = (int64_t)(stride * image_height);
+  if (alloc_size < 0 || alloc_size != (tsize_t)alloc_size) goto End;
+
+  raster = (uint32_t*)_TIFFmalloc((tsize_t)alloc_size);
+  if (raster != NULL) {
+    if (TIFFReadRGBAImageOriented(tif, image_width, image_height, raster,
+                                  ORIENTATION_TOPLEFT, 1)) {
+      pic->width = image_width;
+      pic->height = image_height;
+      // TIFF data is ABGR
+#ifdef WORDS_BIGENDIAN
+      TIFFSwabArrayOfLong(raster, image_width * image_height);
+#endif
+      // if we have an alpha channel, we must un-multiply from rgbA to RGBA
+      if (extra_samples == 1 && extra_samples_ptr != NULL &&
+          extra_samples_ptr[0] == EXTRASAMPLE_ASSOCALPHA) {
+        uint32_t y;
+        uint8_t* tmp = (uint8_t*)raster;
+        for (y = 0; y < image_height; ++y) {
+          MultARGBRow(tmp, image_width);
+          tmp += stride;
+        }
+      }
+      ok = keep_alpha
+         ? WebPPictureImportRGBA(pic, (const uint8_t*)raster, (int)stride)
+         : WebPPictureImportRGBX(pic, (const uint8_t*)raster, (int)stride);
+    }
+    _TIFFfree(raster);
+  } else {
+    fprintf(stderr, "Error allocating TIFF RGBA memory!\n");
+  }
+
+  if (ok) {
+    if (metadata != NULL) {
+      ok = ExtractMetadataFromTIFF(tif, metadata);
+      if (!ok) {
+        fprintf(stderr, "Error extracting TIFF metadata!\n");
+        MetadataFree(metadata);
+        WebPPictureFree(pic);
+      }
+    }
+  }
+ End:
+  TIFFClose(tif);
+  return ok;
+}
+#else  // !WEBP_HAVE_TIFF
+int ReadTIFF(const uint8_t* const data, size_t data_size,
+             struct WebPPicture* const pic, int keep_alpha,
+             struct Metadata* const metadata) {
+  (void)data;
+  (void)data_size;
+  (void)pic;
+  (void)keep_alpha;
+  (void)metadata;
+  fprintf(stderr, "TIFF support not compiled. Please install the libtiff "
+          "development package before building.\n");
+  return 0;
+}
+#endif  // WEBP_HAVE_TIFF
+
+// -----------------------------------------------------------------------------

imageio/tiffdec.h

@@ -0,0 +1,37 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// TIFF decode.
+
+#ifndef WEBP_IMAGEIO_TIFFDEC_H_
+#define WEBP_IMAGEIO_TIFFDEC_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+// Reads a TIFF from 'data', returning the decoded output in 'pic'.
+// Output is RGBA or YUVA, depending on pic->use_argb value.
+// If 'keep_alpha' is true and the TIFF has an alpha channel, the output is RGBA
+// or YUVA. Otherwise, alpha channel is dropped and output is RGB or YUV.
+// Returns true on success.
+int ReadTIFF(const uint8_t* const data, size_t data_size,
+             struct WebPPicture* const pic, int keep_alpha,
+             struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_TIFFDEC_H_

imageio/webpdec.c

@@ -0,0 +1,244 @@
+// Copyright 2014 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// WebP decode.
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "./webpdec.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "webp/decode.h"
+#include "webp/demux.h"
+#include "webp/encode.h"
+#include "../examples/unicode.h"
+#include "./imageio_util.h"
+#include "./metadata.h"
+
+//------------------------------------------------------------------------------
+// WebP decoding
+
+static const char* const kStatusMessages[VP8_STATUS_NOT_ENOUGH_DATA + 1] = {
+  "OK", "OUT_OF_MEMORY", "INVALID_PARAM", "BITSTREAM_ERROR",
+  "UNSUPPORTED_FEATURE", "SUSPENDED", "USER_ABORT", "NOT_ENOUGH_DATA"
+};
+
+static void PrintAnimationWarning(const WebPDecoderConfig* const config) {
+  if (config->input.has_animation) {
+    fprintf(stderr,
+            "Error! Decoding of an animated WebP file is not supported.\n"
+            "       Use webpmux to extract the individual frames or\n"
+            "       vwebp to view this image.\n");
+  }
+}
+
+void PrintWebPError(const char* const in_file, int status) {
+  WFPRINTF(stderr, "Decoding of %s failed.\n", (const W_CHAR*)in_file);
+  fprintf(stderr, "Status: %d", status);
+  if (status >= VP8_STATUS_OK && status <= VP8_STATUS_NOT_ENOUGH_DATA) {
+    fprintf(stderr, "(%s)", kStatusMessages[status]);
+  }
+  fprintf(stderr, "\n");
+}
+
+int LoadWebP(const char* const in_file,
+             const uint8_t** data, size_t* data_size,
+             WebPBitstreamFeatures* bitstream) {
+  VP8StatusCode status;
+  WebPBitstreamFeatures local_features;
+  if (!ImgIoUtilReadFile(in_file, data, data_size)) return 0;
+
+  if (bitstream == NULL) {
+    bitstream = &local_features;
+  }
+
+  status = WebPGetFeatures(*data, *data_size, bitstream);
+  if (status != VP8_STATUS_OK) {
+    WebPFree((void*)*data);
+    *data = NULL;
+    *data_size = 0;
+    PrintWebPError(in_file, status);
+    return 0;
+  }
+  return 1;
+}
+
+//------------------------------------------------------------------------------
+
+VP8StatusCode DecodeWebP(const uint8_t* const data, size_t data_size,
+                         WebPDecoderConfig* const config) {
+  if (config == NULL) return VP8_STATUS_INVALID_PARAM;
+  PrintAnimationWarning(config);
+  return WebPDecode(data, data_size, config);
+}
+
+VP8StatusCode DecodeWebPIncremental(
+    const uint8_t* const data, size_t data_size,
+    WebPDecoderConfig* const config) {
+  VP8StatusCode status = VP8_STATUS_OK;
+  if (config == NULL) return VP8_STATUS_INVALID_PARAM;
+
+  PrintAnimationWarning(config);
+
+  // Decoding call.
+  {
+    WebPIDecoder* const idec = WebPIDecode(data, data_size, config);
+    if (idec == NULL) {
+      fprintf(stderr, "Failed during WebPIDecode().\n");
+      return VP8_STATUS_OUT_OF_MEMORY;
+    } else {
+      status = WebPIUpdate(idec, data, data_size);
+      WebPIDelete(idec);
+    }
+  }
+  return status;
+}
+
+// -----------------------------------------------------------------------------
+// Metadata
+
+static int ExtractMetadata(const uint8_t* const data, size_t data_size,
+                           Metadata* const metadata) {
+  WebPData webp_data = { data, data_size };
+  WebPDemuxer* const demux = WebPDemux(&webp_data);
+  WebPChunkIterator chunk_iter;
+  uint32_t flags;
+
+  if (demux == NULL) return 0;
+  assert(metadata != NULL);
+
+  flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS);
+
+  if ((flags & ICCP_FLAG) && WebPDemuxGetChunk(demux, "ICCP", 1, &chunk_iter)) {
+    MetadataCopy((const char*)chunk_iter.chunk.bytes, chunk_iter.chunk.size,
+                 &metadata->iccp);
+    WebPDemuxReleaseChunkIterator(&chunk_iter);
+  }
+  if ((flags & EXIF_FLAG) && WebPDemuxGetChunk(demux, "EXIF", 1, &chunk_iter)) {
+    MetadataCopy((const char*)chunk_iter.chunk.bytes, chunk_iter.chunk.size,
+                 &metadata->exif);
+    WebPDemuxReleaseChunkIterator(&chunk_iter);
+  }
+  if ((flags & XMP_FLAG) && WebPDemuxGetChunk(demux, "XMP ", 1, &chunk_iter)) {
+    MetadataCopy((const char*)chunk_iter.chunk.bytes, chunk_iter.chunk.size,
+                 &metadata->xmp);
+    WebPDemuxReleaseChunkIterator(&chunk_iter);
+  }
+  WebPDemuxDelete(demux);
+  return 1;
+}
+
+// -----------------------------------------------------------------------------
+
+int ReadWebP(const uint8_t* const data, size_t data_size,
+             WebPPicture* const pic,
+             int keep_alpha, Metadata* const metadata) {
+  int ok = 0;
+  VP8StatusCode status = VP8_STATUS_OK;
+  WebPDecoderConfig config;
+  WebPDecBuffer* const output_buffer = &config.output;
+  WebPBitstreamFeatures* const bitstream = &config.input;
+
+  if (data == NULL || data_size == 0 || pic == NULL) return 0;
+
+  if (!WebPInitDecoderConfig(&config)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    return 0;
+  }
+
+  status = WebPGetFeatures(data, data_size, bitstream);
+  if (status != VP8_STATUS_OK) {
+    PrintWebPError("input data", status);
+    return 0;
+  }
+
+  do {
+    const int has_alpha = keep_alpha && bitstream->has_alpha;
+    uint64_t stride;
+    pic->width = bitstream->width;
+    pic->height = bitstream->height;
+    if (pic->use_argb) {
+      stride = (uint64_t)bitstream->width * 4;
+    } else {
+      stride = (uint64_t)bitstream->width * (has_alpha ? 5 : 3) / 2;
+      pic->colorspace = has_alpha ? WEBP_YUV420A : WEBP_YUV420;
+    }
+
+    if (!ImgIoUtilCheckSizeArgumentsOverflow(stride, bitstream->height)) {
+      status = VP8_STATUS_OUT_OF_MEMORY;
+      break;
+    }
+
+    ok = WebPPictureAlloc(pic);
+    if (!ok) {
+      status = VP8_STATUS_OUT_OF_MEMORY;
+      break;
+    }
+    if (pic->use_argb) {
+#ifdef WORDS_BIGENDIAN
+      output_buffer->colorspace = MODE_ARGB;
+#else
+      output_buffer->colorspace = MODE_BGRA;
+#endif
+      output_buffer->u.RGBA.rgba = (uint8_t*)pic->argb;
+      output_buffer->u.RGBA.stride = pic->argb_stride * sizeof(uint32_t);
+      output_buffer->u.RGBA.size = output_buffer->u.RGBA.stride * pic->height;
+    } else {
+      output_buffer->colorspace = has_alpha ? MODE_YUVA : MODE_YUV;
+      output_buffer->u.YUVA.y = pic->y;
+      output_buffer->u.YUVA.u = pic->u;
+      output_buffer->u.YUVA.v = pic->v;
+      output_buffer->u.YUVA.a = has_alpha ? pic->a : NULL;
+      output_buffer->u.YUVA.y_stride = pic->y_stride;
+      output_buffer->u.YUVA.u_stride = pic->uv_stride;
+      output_buffer->u.YUVA.v_stride = pic->uv_stride;
+      output_buffer->u.YUVA.a_stride = has_alpha ? pic->a_stride : 0;
+      output_buffer->u.YUVA.y_size = pic->height * pic->y_stride;
+      output_buffer->u.YUVA.u_size = (pic->height + 1) / 2 * pic->uv_stride;
+      output_buffer->u.YUVA.v_size = (pic->height + 1) / 2 * pic->uv_stride;
+      output_buffer->u.YUVA.a_size = pic->height * pic->a_stride;
+    }
+    output_buffer->is_external_memory = 1;
+
+    status = DecodeWebP(data, data_size, &config);
+    ok = (status == VP8_STATUS_OK);
+    if (ok && !keep_alpha && pic->use_argb) {
+      // Need to wipe out the alpha value, as requested.
+      int x, y;
+      uint32_t* argb = pic->argb;
+      for (y = 0; y < pic->height; ++y) {
+        for (x = 0; x < pic->width; ++x) argb[x] |= 0xff000000u;
+        argb += pic->argb_stride;
+      }
+    }
+  } while (0);   // <- so we can 'break' out of the loop
+
+  if (status != VP8_STATUS_OK) {
+    PrintWebPError("input data", status);
+    ok = 0;
+  }
+
+  WebPFreeDecBuffer(output_buffer);
+
+  if (ok && metadata != NULL) {
+    ok = ExtractMetadata(data, data_size, metadata);
+    if (!ok) {
+      PrintWebPError("metadata", VP8_STATUS_BITSTREAM_ERROR);
+    }
+  }
+  if (!ok) WebPPictureFree(pic);
+  return ok;
+}
+
+// -----------------------------------------------------------------------------

imageio/webpdec.h

@@ -0,0 +1,67 @@
+// Copyright 2014 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// WebP decode.
+
+#ifndef WEBP_IMAGEIO_WEBPDEC_H_
+#define WEBP_IMAGEIO_WEBPDEC_H_
+
+#include "webp/decode.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+//------------------------------------------------------------------------------
+// WebP decoding
+
+// Prints an informative error message regarding decode failure of 'in_file'.
+// 'status' is treated as a VP8StatusCode and if valid will be printed as a
+// text string.
+void PrintWebPError(const char* const in_file, int status);
+
+// Reads a WebP from 'in_file', returning the contents and size in 'data' and
+// 'data_size'. If not NULL, 'bitstream' is populated using WebPGetFeatures().
+// Returns true on success.
+int LoadWebP(const char* const in_file,
+             const uint8_t** data, size_t* data_size,
+             WebPBitstreamFeatures* bitstream);
+
+// Decodes the WebP contained in 'data'.
+// 'config' is a structure previously initialized by WebPInitDecoderConfig().
+// 'config->output' should have the desired colorspace selected.
+// Returns the decoder status. On success 'config->output' will contain the
+// decoded picture.
+VP8StatusCode DecodeWebP(const uint8_t* const data, size_t data_size,
+                         WebPDecoderConfig* const config);
+
+// Same as DecodeWebP(), but using the incremental decoder.
+VP8StatusCode DecodeWebPIncremental(
+    const uint8_t* const data, size_t data_size,
+    WebPDecoderConfig* const config);
+
+//------------------------------------------------------------------------------
+
+// Decodes a WebP contained in 'data', returning the decoded output in 'pic'.
+// Output is RGBA or YUVA, depending on pic->use_argb value.
+// If 'keep_alpha' is true and the WebP has an alpha channel, the output is RGBA
+// or YUVA. Otherwise, alpha channel is dropped and output is RGB or YUV.
+// Returns true on success.
+int ReadWebP(const uint8_t* const data, size_t data_size,
+             struct WebPPicture* const pic,
+             int keep_alpha, struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_WEBPDEC_H_

imageio/wicdec.c

@@ -0,0 +1,413 @@
+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Windows Imaging Component (WIC) decode.
+
+#include "./wicdec.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+#ifdef HAVE_WINCODEC_H
+#ifdef __MINGW32__
+#define INITGUID  // Without this GUIDs are declared extern and fail to link
+#endif
+#define CINTERFACE
+#define COBJMACROS
+#define _WIN32_IE 0x500  // Workaround bug in shlwapi.h when compiling C++
+                         // code with COBJMACROS.
+#include <ole2.h>  // CreateStreamOnHGlobal()
+#include <shlwapi.h>
+#include <tchar.h>
+#include <windows.h>
+#include <wincodec.h>
+
+#include "../examples/unicode.h"
+#include "./imageio_util.h"
+#include "./metadata.h"
+#include "webp/encode.h"
+
+#define IFS(fn)                                                     \
+  do {                                                              \
+    if (SUCCEEDED(hr)) {                                            \
+      hr = (fn);                                                    \
+      if (FAILED(hr)) fprintf(stderr, #fn " failed %08lx\n", hr);   \
+    }                                                               \
+  } while (0)
+
+// modified version of DEFINE_GUID from guiddef.h.
+#define WEBP_DEFINE_GUID(name, l, w1, w2, b1, b2, b3, b4, b5, b6, b7, b8) \
+  static const GUID name = \
+      { l, w1, w2, { b1, b2,  b3,  b4,  b5,  b6,  b7,  b8 } }
+
+#ifdef __cplusplus
+#define MAKE_REFGUID(x) (x)
+#else
+#define MAKE_REFGUID(x) &(x)
+#endif
+
+typedef struct WICFormatImporter {
+  const GUID* pixel_format;
+  int bytes_per_pixel;
+  int (*import)(WebPPicture* const, const uint8_t* const, int);
+} WICFormatImporter;
+
+// From Microsoft SDK 7.0a -- wincodec.h
+// Create local copies for compatibility when building against earlier
+// versions of the SDK.
+WEBP_DEFINE_GUID(GUID_WICPixelFormat24bppBGR_,
+                 0x6fddc324, 0x4e03, 0x4bfe,
+                 0xb1, 0x85, 0x3d, 0x77, 0x76, 0x8d, 0xc9, 0x0c);
+WEBP_DEFINE_GUID(GUID_WICPixelFormat24bppRGB_,
+                 0x6fddc324, 0x4e03, 0x4bfe,
+                 0xb1, 0x85, 0x3d, 0x77, 0x76, 0x8d, 0xc9, 0x0d);
+WEBP_DEFINE_GUID(GUID_WICPixelFormat32bppBGRA_,
+                 0x6fddc324, 0x4e03, 0x4bfe,
+                 0xb1, 0x85, 0x3d, 0x77, 0x76, 0x8d, 0xc9, 0x0f);
+WEBP_DEFINE_GUID(GUID_WICPixelFormat32bppRGBA_,
+                 0xf5c7ad2d, 0x6a8d, 0x43dd,
+                 0xa7, 0xa8, 0xa2, 0x99, 0x35, 0x26, 0x1a, 0xe9);
+WEBP_DEFINE_GUID(GUID_WICPixelFormat64bppBGRA_,
+                 0x1562ff7c, 0xd352, 0x46f9,
+                 0x97, 0x9e, 0x42, 0x97, 0x6b, 0x79, 0x22, 0x46);
+WEBP_DEFINE_GUID(GUID_WICPixelFormat64bppRGBA_,
+                 0x6fddc324, 0x4e03, 0x4bfe,
+                 0xb1, 0x85, 0x3d, 0x77, 0x76, 0x8d, 0xc9, 0x16);
+
+static HRESULT OpenInputStream(const char* filename, IStream** stream) {
+  HRESULT hr = S_OK;
+  if (!WSTRCMP(filename, "-")) {
+    const uint8_t* data = NULL;
+    size_t data_size = 0;
+    const int ok = ImgIoUtilReadFile(filename, &data, &data_size);
+    if (ok) {
+      HGLOBAL image = GlobalAlloc(GMEM_MOVEABLE, data_size);
+      if (image != NULL) {
+        void* const image_mem = GlobalLock(image);
+        if (image_mem != NULL) {
+          memcpy(image_mem, data, data_size);
+          GlobalUnlock(image);
+          IFS(CreateStreamOnHGlobal(image, TRUE, stream));
+        } else {
+          hr = E_FAIL;
+        }
+      } else {
+        hr = E_OUTOFMEMORY;
+      }
+      free((void*)data);
+    } else {
+      hr = E_FAIL;
+    }
+  } else {
+    IFS(SHCreateStreamOnFile((const LPTSTR)filename, STGM_READ, stream));
+  }
+
+  if (FAILED(hr)) {
+    _ftprintf(stderr, _T("Error opening input file %s (%08lx)\n"),
+              (const LPTSTR)filename, hr);
+  }
+  return hr;
+}
+
+// -----------------------------------------------------------------------------
+// Metadata processing
+
+// Stores the first non-zero sized color profile from 'frame' to 'iccp'.
+// Returns an HRESULT to indicate success or failure. The caller is responsible
+// for freeing 'iccp->bytes' in either case.
+static HRESULT ExtractICCP(IWICImagingFactory* const factory,
+                           IWICBitmapFrameDecode* const frame,
+                           MetadataPayload* const iccp) {
+  HRESULT hr = S_OK;
+  UINT i, count;
+  IWICColorContext** color_contexts;
+
+  IFS(IWICBitmapFrameDecode_GetColorContexts(frame, 0, NULL, &count));
+  if (FAILED(hr) || count == 0) {
+    // Treat unsupported operation as a non-fatal error. See crbug.com/webp/506.
+    return (hr == WINCODEC_ERR_UNSUPPORTEDOPERATION) ? S_OK : hr;
+  }
+
+  color_contexts = (IWICColorContext**)calloc(count, sizeof(*color_contexts));
+  if (color_contexts == NULL) return E_OUTOFMEMORY;
+  for (i = 0; SUCCEEDED(hr) && i < count; ++i) {
+    IFS(IWICImagingFactory_CreateColorContext(factory, &color_contexts[i]));
+  }
+
+  if (SUCCEEDED(hr)) {
+    UINT num_color_contexts;
+    IFS(IWICBitmapFrameDecode_GetColorContexts(frame,
+                                               count, color_contexts,
+                                               &num_color_contexts));
+    assert(FAILED(hr) || num_color_contexts <= count);
+    for (i = 0; SUCCEEDED(hr) && i < num_color_contexts; ++i) {
+      WICColorContextType type;
+      IFS(IWICColorContext_GetType(color_contexts[i], &type));
+      if (SUCCEEDED(hr) && type == WICColorContextProfile) {
+        UINT size;
+        IFS(IWICColorContext_GetProfileBytes(color_contexts[i],
+                                             0, NULL, &size));
+        if (SUCCEEDED(hr) && size > 0) {
+          iccp->bytes = (uint8_t*)malloc(size);
+          if (iccp->bytes == NULL) {
+            hr = E_OUTOFMEMORY;
+            break;
+          }
+          iccp->size = size;
+          IFS(IWICColorContext_GetProfileBytes(color_contexts[i],
+                                               (UINT)iccp->size, iccp->bytes,
+                                               &size));
+          if (SUCCEEDED(hr) && size != iccp->size) {
+            fprintf(stderr, "Warning! ICC profile size (%u) != expected (%u)\n",
+                    size, (uint32_t)iccp->size);
+            iccp->size = size;
+          }
+          break;
+        }
+      }
+    }
+  }
+  for (i = 0; i < count; ++i) {
+    if (color_contexts[i] != NULL) IUnknown_Release(color_contexts[i]);
+  }
+  free(color_contexts);
+  return hr;
+}
+
+static HRESULT ExtractMetadata(IWICImagingFactory* const factory,
+                               IWICBitmapFrameDecode* const frame,
+                               Metadata* const metadata) {
+  // TODO(jzern): add XMP/EXIF extraction.
+  const HRESULT hr = ExtractICCP(factory, frame, &metadata->iccp);
+  if (FAILED(hr)) MetadataFree(metadata);
+  return hr;
+}
+
+// -----------------------------------------------------------------------------
+
+static int HasPalette(GUID pixel_format) {
+  return (IsEqualGUID(MAKE_REFGUID(pixel_format),
+                      MAKE_REFGUID(GUID_WICPixelFormat1bppIndexed)) ||
+          IsEqualGUID(MAKE_REFGUID(pixel_format),
+                      MAKE_REFGUID(GUID_WICPixelFormat2bppIndexed)) ||
+          IsEqualGUID(MAKE_REFGUID(pixel_format),
+                      MAKE_REFGUID(GUID_WICPixelFormat4bppIndexed)) ||
+          IsEqualGUID(MAKE_REFGUID(pixel_format),
+                      MAKE_REFGUID(GUID_WICPixelFormat8bppIndexed)));
+}
+
+static int HasAlpha(IWICImagingFactory* const factory,
+                    IWICBitmapDecoder* const decoder,
+                    IWICBitmapFrameDecode* const frame,
+                    GUID pixel_format) {
+  int has_alpha;
+  if (HasPalette(pixel_format)) {
+    IWICPalette* frame_palette = NULL;
+    IWICPalette* global_palette = NULL;
+    BOOL frame_palette_has_alpha = FALSE;
+    BOOL global_palette_has_alpha = FALSE;
+
+    // A palette may exist at the frame or container level,
+    // check IWICPalette::HasAlpha() for both if present.
+    if (SUCCEEDED(IWICImagingFactory_CreatePalette(factory, &frame_palette)) &&
+        SUCCEEDED(IWICBitmapFrameDecode_CopyPalette(frame, frame_palette))) {
+      IWICPalette_HasAlpha(frame_palette, &frame_palette_has_alpha);
+    }
+    if (SUCCEEDED(IWICImagingFactory_CreatePalette(factory, &global_palette)) &&
+        SUCCEEDED(IWICBitmapDecoder_CopyPalette(decoder, global_palette))) {
+      IWICPalette_HasAlpha(global_palette, &global_palette_has_alpha);
+    }
+    has_alpha = frame_palette_has_alpha || global_palette_has_alpha;
+
+    if (frame_palette != NULL) IUnknown_Release(frame_palette);
+    if (global_palette != NULL) IUnknown_Release(global_palette);
+  } else {
+    has_alpha = IsEqualGUID(MAKE_REFGUID(pixel_format),
+                            MAKE_REFGUID(GUID_WICPixelFormat32bppRGBA_)) ||
+                IsEqualGUID(MAKE_REFGUID(pixel_format),
+                            MAKE_REFGUID(GUID_WICPixelFormat32bppBGRA_)) ||
+                IsEqualGUID(MAKE_REFGUID(pixel_format),
+                            MAKE_REFGUID(GUID_WICPixelFormat64bppRGBA_)) ||
+                IsEqualGUID(MAKE_REFGUID(pixel_format),
+                            MAKE_REFGUID(GUID_WICPixelFormat64bppBGRA_));
+  }
+  return has_alpha;
+}
+
+int ReadPictureWithWIC(const char* const filename,
+                       WebPPicture* const pic, int keep_alpha,
+                       Metadata* const metadata) {
+  // From Microsoft SDK 6.0a -- ks.h
+  // Define a local copy to avoid link errors under mingw.
+  WEBP_DEFINE_GUID(GUID_NULL_, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
+  static const WICFormatImporter kAlphaFormatImporters[] = {
+    { &GUID_WICPixelFormat32bppBGRA_, 4, WebPPictureImportBGRA },
+    { &GUID_WICPixelFormat32bppRGBA_, 4, WebPPictureImportRGBA },
+    { NULL, 0, NULL },
+  };
+  static const WICFormatImporter kNonAlphaFormatImporters[] = {
+    { &GUID_WICPixelFormat24bppBGR_, 3, WebPPictureImportBGR },
+    { &GUID_WICPixelFormat24bppRGB_, 3, WebPPictureImportRGB },
+    { NULL, 0, NULL },
+  };
+  HRESULT hr = S_OK;
+  IWICBitmapFrameDecode* frame = NULL;
+  IWICFormatConverter* converter = NULL;
+  IWICImagingFactory* factory = NULL;
+  IWICBitmapDecoder* decoder = NULL;
+  IStream* stream = NULL;
+  UINT frame_count = 0;
+  UINT width = 0, height = 0;
+  BYTE* rgb = NULL;
+  WICPixelFormatGUID src_pixel_format = GUID_WICPixelFormatUndefined;
+  const WICFormatImporter* importer = NULL;
+  GUID src_container_format = GUID_NULL_;
+  // From Windows Kits\10\Include\10.0.19041.0\um\wincodec.h
+  WEBP_DEFINE_GUID(GUID_ContainerFormatWebp_,
+                   0xe094b0e2, 0x67f2, 0x45b3,
+                   0xb0, 0xea, 0x11, 0x53, 0x37, 0xca, 0x7c, 0xf3);
+  static const GUID* kAlphaContainers[] = {
+    &GUID_ContainerFormatBmp,
+    &GUID_ContainerFormatPng,
+    &GUID_ContainerFormatTiff,
+    &GUID_ContainerFormatWebp_,
+    NULL
+  };
+  int has_alpha = 0;
+  int64_t stride;
+
+  if (filename == NULL || pic == NULL) return 0;
+
+  IFS(CoInitialize(NULL));
+  IFS(CoCreateInstance(MAKE_REFGUID(CLSID_WICImagingFactory), NULL,
+                       CLSCTX_INPROC_SERVER,
+                       MAKE_REFGUID(IID_IWICImagingFactory),
+                       (LPVOID*)&factory));
+  if (hr == REGDB_E_CLASSNOTREG) {
+    fprintf(stderr,
+            "Couldn't access Windows Imaging Component (are you running "
+            "Windows XP SP3 or newer?). Most formats not available. "
+            "Use -s for the available YUV input.\n");
+  }
+  // Prepare for image decoding.
+  IFS(OpenInputStream(filename, &stream));
+  IFS(IWICImagingFactory_CreateDecoderFromStream(
+          factory, stream, NULL,
+          WICDecodeMetadataCacheOnDemand, &decoder));
+  IFS(IWICBitmapDecoder_GetFrameCount(decoder, &frame_count));
+  if (SUCCEEDED(hr)) {
+    if (frame_count == 0) {
+      fprintf(stderr, "No frame found in input file.\n");
+      hr = E_FAIL;
+    } else if (frame_count > 1) {
+      // WIC will be tried before native WebP decoding so avoid duplicating the
+      // error message.
+      hr = E_FAIL;
+    }
+  }
+  IFS(IWICBitmapDecoder_GetFrame(decoder, 0, &frame));
+  IFS(IWICBitmapFrameDecode_GetPixelFormat(frame, &src_pixel_format));
+  IFS(IWICBitmapDecoder_GetContainerFormat(decoder, &src_container_format));
+
+  if (SUCCEEDED(hr) && keep_alpha) {
+    const GUID** guid;
+    for (guid = kAlphaContainers; *guid != NULL; ++guid) {
+      if (IsEqualGUID(MAKE_REFGUID(src_container_format),
+                      MAKE_REFGUID(**guid))) {
+        has_alpha = HasAlpha(factory, decoder, frame, src_pixel_format);
+        break;
+      }
+    }
+  }
+
+  // Prepare for pixel format conversion (if necessary).
+  IFS(IWICImagingFactory_CreateFormatConverter(factory, &converter));
+
+  for (importer = has_alpha ? kAlphaFormatImporters : kNonAlphaFormatImporters;
+       hr == S_OK && importer->import != NULL; ++importer) {
+    BOOL can_convert;
+    const HRESULT cchr = IWICFormatConverter_CanConvert(
+        converter,
+        MAKE_REFGUID(src_pixel_format),
+        MAKE_REFGUID(*importer->pixel_format),
+        &can_convert);
+    if (SUCCEEDED(cchr) && can_convert) break;
+  }
+  if (importer->import == NULL) hr = E_FAIL;
+
+  IFS(IWICFormatConverter_Initialize(converter, (IWICBitmapSource*)frame,
+                                     importer->pixel_format,
+                                     WICBitmapDitherTypeNone,
+                                     NULL, 0.0, WICBitmapPaletteTypeCustom));
+
+  // Decode.
+  IFS(IWICFormatConverter_GetSize(converter, &width, &height));
+  stride = (int64_t)importer->bytes_per_pixel * width * sizeof(*rgb);
+  if (stride != (int)stride ||
+      !ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) {
+    hr = E_FAIL;
+  }
+
+  if (SUCCEEDED(hr)) {
+    rgb = (BYTE*)malloc((size_t)stride * height);
+    if (rgb == NULL)
+      hr = E_OUTOFMEMORY;
+  }
+  IFS(IWICFormatConverter_CopyPixels(converter, NULL,
+                                     (UINT)stride, (UINT)stride * height, rgb));
+
+  // WebP conversion.
+  if (SUCCEEDED(hr)) {
+    int ok;
+    pic->width = width;
+    pic->height = height;
+    pic->use_argb = 1;    // For WIC, we always force to argb
+    ok = importer->import(pic, rgb, (int)stride);
+    if (!ok) hr = E_FAIL;
+  }
+  if (SUCCEEDED(hr)) {
+    if (metadata != NULL) {
+      hr = ExtractMetadata(factory, frame, metadata);
+      if (FAILED(hr)) {
+        fprintf(stderr, "Error extracting image metadata using WIC!\n");
+      }
+    }
+  }
+
+  // Cleanup.
+  if (converter != NULL) IUnknown_Release(converter);
+  if (frame != NULL) IUnknown_Release(frame);
+  if (decoder != NULL) IUnknown_Release(decoder);
+  if (factory != NULL) IUnknown_Release(factory);
+  if (stream != NULL) IUnknown_Release(stream);
+  free(rgb);
+  return SUCCEEDED(hr);
+}
+#else  // !HAVE_WINCODEC_H
+int ReadPictureWithWIC(const char* const filename,
+                       struct WebPPicture* const pic, int keep_alpha,
+                       struct Metadata* const metadata) {
+  (void)filename;
+  (void)pic;
+  (void)keep_alpha;
+  (void)metadata;
+  fprintf(stderr, "Windows Imaging Component (WIC) support not compiled. "
+                  "Visual Studio and mingw-w64 builds support WIC. Make sure "
+                  "wincodec.h detection is working correctly if using autoconf "
+                  "and HAVE_WINCODEC_H is defined before building.\n");
+  return 0;
+}
+#endif  // HAVE_WINCODEC_H
+
+// -----------------------------------------------------------------------------

imageio/wicdec.h

@@ -0,0 +1,34 @@
+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Windows Imaging Component (WIC) decode.
+
+#ifndef WEBP_IMAGEIO_WICDEC_H_
+#define WEBP_IMAGEIO_WICDEC_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+// Reads an image from 'filename', returning the decoded output in 'pic'.
+// If 'keep_alpha' is true and the image has an alpha channel, the output is
+// RGBA otherwise it will be RGB. pic->use_argb is always forced to true.
+// Returns true on success.
+int ReadPictureWithWIC(const char* const filename,
+                       struct WebPPicture* const pic, int keep_alpha,
+                       struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_WICDEC_H_

infra/common.sh

@@ -0,0 +1,106 @@
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+log_err() {
+  echo "[$(date +'%Y-%m-%dT%H:%M:%S%z')]: $*" >&2
+}
+
+#######################################
+# Create build directory. Build directory will be deleted if it exists.
+# Arguments:
+#   None.
+# Returns:
+#   mkdir result.
+#######################################
+make_build_dir() {
+  if [[ "$#" -ne 1 ]]; then
+    return 1
+  fi
+
+  local build_dir
+  build_dir="$1"
+  rm -rf "${build_dir}"
+  mkdir -p "${build_dir}"
+}
+
+#######################################
+# Cleanup files from the build directory.
+# Globals:
+#   LIBWEBP_ROOT repository's root path.
+# Arguments:
+#   $1 build directory.
+#######################################
+cleanup() {
+  # $1 is not completely removed to allow for binary artifacts to be
+  # extracted.
+  find "${1:?"Build directory not defined"}" \
+    \( -name "*.[ao]" -o -name "*.l[ao]" \) -exec rm -f {} +
+}
+
+#######################################
+# Setup ccache for toolchain.
+# Globals:
+#   PATH
+# Arguments:
+#   None.
+#######################################
+setup_ccache() {
+  if [[ -x "$(command -v ccache)" ]]; then
+    export CCACHE_CPP2=yes
+    export PATH="/usr/lib/ccache:${PATH}"
+  fi
+}
+
+#######################################
+# Detects whether test block should be run in the current test shard.
+# Globals:
+#   TEST_TOTAL_SHARDS: Valid range: [1, N]. Defaults to 1.
+#   TEST_SHARD_INDEX: Valid range: [0, TEST_TOTAL_SHARDS). Defaults to 0.
+#   libwebp_test_id: current test number; incremented with each call.
+# Arguments:
+#   None
+# Returns:
+#   true if the shard is active
+#   false if the shard is inactive
+#######################################
+shard_should_run() {
+  TEST_TOTAL_SHARDS=${TEST_TOTAL_SHARDS:=1}
+  TEST_SHARD_INDEX=${TEST_SHARD_INDEX:=0}
+  libwebp_test_id=${libwebp_test_id:=-1}
+  : $((libwebp_test_id += 1))
+
+  if [[ "${TEST_SHARD_INDEX}" -lt 0 ||
+    "${TEST_SHARD_INDEX}" -ge "${TEST_TOTAL_SHARDS}" ]]; then
+    log_err "Invalid TEST_SHARD_INDEX (${TEST_SHARD_INDEX})!" \
+      "Expected [0, ${TEST_TOTAL_SHARDS})."
+  fi
+
+  [[ "$((libwebp_test_id % TEST_TOTAL_SHARDS))" -eq "${TEST_SHARD_INDEX}" ]]
+}

infra/compile.sh

@@ -0,0 +1,401 @@
+#!/bin/bash
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+set -xe
+LIBWEBP_ROOT="$(realpath "$(dirname "$0")/..")"
+WORKSPACE=${WORKSPACE:-"$(mktemp -d -t webp.XXX)"}
+
+# shellcheck source=infra/common.sh
+source "${LIBWEBP_ROOT}/infra/common.sh"
+
+usage() {
+  cat << EOF
+Usage: compile.sh BUILD_TYPE TARGET
+Options:
+BUILD_TYPE  supported build type: (shared, static, static-debug)
+TARGET      supported target platforms:
+              aarch64-linux-clang
+              aarch64-linux-gnu
+              arm-linux-gnueabi
+              arm-neon-linux-gnueabi
+              cmake
+              cmake-aarch64
+              cmake-arm
+              cmake-clang
+              disable-near-lossless
+              disable-sse4.1
+              disable-stats
+              force-aligned-32
+              force-aligned-64
+              gradle
+              i686-linux-asan
+              i686-linux-clang
+              i686-linux-gnu
+              i686-w64-mingw32
+              mips2el-linux-gnu
+              mips32dspr2el-linux-gnu
+              mips32eb-linux-gnu
+              mips32el-linux-gnu
+              mips32r2el-linux-gnu
+              mips32r5el-linux-gnu
+              mips64r2el-linux-gnu
+              mips64r6el-linux-gnu
+              native
+              reduce-csp
+              reduce-size
+              reduce-size-disable-stats
+              visibility-default-gnu
+              visibility-hidden-clang
+              visibility-hidden-gnu
+              wasm
+              x86_64-linux-clang
+              x86_64-linux-gnu
+              x86_64-linux-msan
+              x86_64-w64-mingw32
+Environment variables:
+WORKSPACE   directory where the build is done
+EOF
+}
+
+################################################################################
+echo "Building libwebp in ${WORKSPACE}"
+
+if [[ ! -d "${WORKSPACE}" ]]; then
+  log_err "${WORKSPACE} directory does not exist"
+  exit 1
+fi
+
+BUILD_TYPE=${1:?"Build type not defined.$(
+  echo
+  usage
+)"}
+TARGET=${2:?"Target not defined.$(
+  echo
+  usage
+)"}
+readonly BUILD_DIR="${WORKSPACE}/build-${BUILD_TYPE}"
+
+trap 'cleanup ${BUILD_DIR}' EXIT
+make_build_dir "${BUILD_DIR}"
+
+config_flags=()
+case "${BUILD_TYPE}" in
+  shared*) ;;  # Valid BUILD_TYPE but no setup required
+  static*) config_flags+=("--disable-shared") ;;
+  experimental) config_flags+=("--enable-experimental") ;;
+  *)
+    log_err "Invalid BUILD_TYPE"
+    usage
+    exit 1
+    ;;
+esac
+
+if grep -m 1 -q "enable-asserts" "${LIBWEBP_ROOT}/configure.ac"; then
+  config_flags+=("--enable-asserts")
+fi
+
+case "${TARGET}" in
+  aarch64-linux-clang)
+    TARGET="aarch64-linux-gnu"
+    CC="clang"
+    CC="${CC} --target=aarch64-linux-gnu"
+    export CC
+    export CFLAGS="-isystem /usr/aarch64-linux-gnu/include"
+    ;;
+  arm-linux-gnueabi)
+    export CFLAGS="-O3 -march=armv7-a -mfloat-abi=softfp -ftree-vectorize"
+    ;;
+  arm-neon-linux-gnueabi)
+    TARGET="arm-linux-gnueabi"
+    CFLAGS="-O3 -march=armv7-a -mfpu=neon -mfloat-abi=softfp -ftree-vectorize"
+    export CFLAGS
+    ;;
+  mips2el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips2"
+    TARGET="mipsel-linux-gnu"
+    ;;
+  mips32el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips32"
+    TARGET="mipsel-linux-gnu"
+    ;;
+  mips32r2el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips32r2"
+    TARGET="mipsel-linux-gnu"
+    ;;
+  mips32dspr2el-linux-gnu)
+    export CFLAGS="-EL -O2 -mdspr2"
+    TARGET="mipsel-linux-gnu"
+    ;;
+  mips32r5el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips32r5 -mmsa"
+    TARGET="mipsel-linux-gnu"
+    ;;
+  mips32eb-linux-gnu)
+    export CFLAGS="-EB -O2 -mips32"
+    TARGET="mips-linux-gnu"
+    ;;
+  mips64r2el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips64r2 -mabi=64"
+    TARGET="mips64el-linux-gnuabi64"
+    ;;
+  mips64r6el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips64r6 -mabi=64 -mmsa"
+    TARGET="mips-img-linux-gnu"
+    ;;
+  i686-linux-gnu)
+    export CC="gcc -m32"
+    ;;
+  i686-linux-clang)
+    TARGET="i686-linux-gnu"
+    export CC="clang -m32"
+    ;;
+  i686-linux-asan)
+    TARGET="i686-linux-gnu"
+    export CC="clang -m32 -fsanitize=address"
+    ;;
+  i686-linux-msan)
+    TARGET="i686-linux-gnu"
+    export CC="clang -m32 -fsanitize=memory"
+    ;;
+  x86_64-linux-clang)
+    TARGET="x86_64-linux-gnu"
+    export CC=clang
+    ;;
+  x86_64-linux-msan)
+    TARGET="x86_64-linux-gnu"
+    export CC="clang -fsanitize=memory"
+    ;;
+  force-aligned-32)
+    config_flags+=("--enable-aligned")
+    TARGET="i686-linux-gnu"
+    export CC="gcc -m32"
+    ;;
+  force-aligned-64)
+    config_flags+=("--enable-aligned")
+    TARGET="x86_64-linux-gnu"
+    ;;
+  visibility-default-*)
+    export CFLAGS="-O2 -g -fvisibility=default"
+    TARGET="x86_64-linux-gnu"
+    ;;
+  visibility-hidden-*)
+    export CFLAGS="-O2 -g -fvisibility=hidden"
+    if [[ "${TARGET}" = "visibility-hidden-clang" ]]; then
+      export CC=clang
+    fi
+    TARGET="x86_64-linux-gnu"
+    ;;
+  disable-sse4.1)
+    grep "${TARGET}" "${LIBWEBP_ROOT}/configure.ac" || exit 0
+    config_flags+=("--${TARGET}")
+    TARGET="x86_64-linux-gnu"
+    ;;
+  disable-near-lossless)
+    grep "${TARGET}" "${LIBWEBP_ROOT}/configure.ac" || exit 0
+    config_flags+=("--${TARGET}")
+    TARGET="x86_64-linux-gnu"
+    ;;
+  disable-stats)
+    git -C "${LIBWEBP_ROOT}" grep WEBP_DISABLE_STATS || exit 0
+    export CFLAGS="-O2 -g -DWEBP_DISABLE_STATS"
+    TARGET="x86_64-linux-gnu"
+    ;;
+  reduce-size)
+    git -C "${LIBWEBP_ROOT}" grep WEBP_REDUCE_SIZE || exit 0
+    export CFLAGS="-O2 -g -DWEBP_REDUCE_SIZE"
+    TARGET="x86_64-linux-gnu"
+    ;;
+  reduce-size-disable-stats)
+    git -C "${LIBWEBP_ROOT}" grep -e WEBP_DISABLE_STATS -e WEBP_REDUCE_SIZE \
+      || exit 0
+    export CFLAGS="-O2 -g -DWEBP_DISABLE_STATS -DWEBP_REDUCE_SIZE"
+    TARGET="x86_64-linux-gnu"
+    ;;
+  reduce-csp)
+    git -C "${LIBWEBP_ROOT}" grep WEBP_REDUCE_CSP || exit 0
+    export CFLAGS="-O2 -g -DWEBP_REDUCE_CSP"
+    TARGET="x86_64-linux-gnu"
+    ;;
+  x86_64-linux-gnu | *mingw32 | aarch64*) ;;  # Default target configuration
+  # non-configure based builds
+  native)
+    setup_ccache
+    # exercise makefile.unix then quit
+    make -C "${LIBWEBP_ROOT}" -f makefile.unix -j all
+    for tgt in extras examples/anim_diff; do
+      grep -q -m 1 "${tgt}" "${LIBWEBP_ROOT}/makefile.unix" \
+        && make -C "${LIBWEBP_ROOT}" -f makefile.unix -j "${tgt}"
+    done
+    [[ -d "${LIBWEBP_ROOT}/tests/fuzzer" ]] \
+      && make -j -C "${LIBWEBP_ROOT}/tests/fuzzer" -f makefile.unix
+    exit 0
+    ;;
+  cmake*)
+    setup_ccache
+    # exercise cmake then quit
+    opts=()
+    case "${TARGET}" in
+      cmake-clang)
+        opts+=("-DCMAKE_C_COMPILER=clang")
+        ;;
+      cmake-arm)
+        opts+=("-DCMAKE_C_COMPILER=arm-linux-gnueabi-gcc")
+        case "${GERRIT_BRANCH:-}" in
+          portable-intrinsics | 0.6.1) exit 0 ;;
+          *) ;;  # Skip configuration
+        esac
+        ;;
+      cmake-aarch64)
+        opts+=("-DCMAKE_C_COMPILER=aarch64-linux-gnu-gcc")
+        case "${GERRIT_BRANCH:-}" in
+          portable-intrinsics | 0.6.1) exit 0 ;;
+          *) ;;  # Skip configuration
+        esac
+        ;;
+      *) ;;  # Skip configuration
+    esac
+    case "${BUILD_TYPE}" in
+      static*)
+        opts+=("-DBUILD_SHARED_LIBS=OFF")
+        ;;
+      experimental)
+        opts+=("-DWEBP_EXPERIMENTAL_FEATURES=ON" "-DBUILD_SHARED_LIBS=ON")
+        ;;
+      *)
+        opts+=("-DBUILD_SHARED_LIBS=ON")
+        ;;
+    esac
+    case "${BUILD_TYPE}" in
+      *debug) opts+=("-DCMAKE_BUILD_TYPE=Debug") ;;
+      *) opts+=("-DCMAKE_BUILD_TYPE=RelWithDebInfo") ;;
+    esac
+    cd "${BUILD_DIR}"
+    opts+=("-DWEBP_BUILD_CWEBP=ON" "-DWEBP_BUILD_DWEBP=ON")
+    grep -m 1 -q WEBP_BUILD_GIF2WEBP "${LIBWEBP_ROOT}/CMakeLists.txt" \
+      && opts+=("-DWEBP_BUILD_GIF2WEBP=ON")
+    grep -m 1 -q WEBP_BUILD_IMG2WEBP "${LIBWEBP_ROOT}/CMakeLists.txt" \
+      && opts+=("-DWEBP_BUILD_IMG2WEBP=ON")
+    cmake "${opts[@]}" "${LIBWEBP_ROOT}"
+    make VERBOSE=1 -j
+    case "${BUILD_TYPE}" in
+      static)
+        mkdir -p examples
+        cp [cd]webp examples
+        ;;
+      *) ;;  # Skip configuration.
+    esac
+
+    grep "install" "${LIBWEBP_ROOT}/CMakeLists.txt" || exit 0
+
+    make DESTDIR="${BUILD_DIR}/webp-install" install/strip
+    mkdir tmp
+    cd tmp
+    cat > CMakeLists.txt << EOF
+cmake_minimum_required(VERSION 2.8.7)
+
+project(libwebp C)
+
+find_package(WebP)
+if (NOT WebP_FOUND)
+  message(FATAL_ERROR "WebP package not found")
+endif ()
+message("WebP_FOUND: \${WebP_FOUND}")
+message("WebP_INCLUDE_DIRS: \${WebP_INCLUDE_DIRS}")
+message("WebP_LIBRARIES: \${WebP_LIBRARIES}")
+message("WEBP_INCLUDE_DIRS: \${WEBP_INCLUDE_DIRS}")
+message("WEBP_LIBRARIES: \${WEBP_LIBRARIES}")
+EOF
+    cmake . "${opts[@]}" \
+      "-DCMAKE_PREFIX_PATH=${BUILD_DIR}/webp-install/usr/local"
+    exit 0
+    ;;
+  gradle)
+    setup_ccache
+    # exercise gradle then quit
+    [[ -f "${LIBWEBP_ROOT}/gradlew" ]] || exit 0
+
+    cd "${BUILD_DIR}"
+    # TODO -g / --gradle-user-home could be used if there's a race between jobs
+    "${LIBWEBP_ROOT}/gradlew" -p "${LIBWEBP_ROOT}" buildAllExecutables
+    exit 0
+    ;;
+  wasm)
+    grep -m 1 -q WEBP_ENABLE_WASM "${LIBWEBP_ROOT}/CMakeLists.txt" || exit 0
+    opts+=("-DCMAKE_C_COMPILER=clang" "-DWEBP_ENABLE_WASM=ON")
+    opts+=("-DWEBP_BUILD_CWEBP=ON" "-DWEBP_BUILD_DWEBP=ON")
+    case "${BUILD_TYPE}" in
+      *debug) opts+=("-DCMAKE_BUILD_TYPE=Debug") ;;
+      *) opts+=("-DCMAKE_BUILD_TYPE=RelWithDebInfo") ;;
+    esac
+    cd "${BUILD_DIR}"
+    cmake "${opts[@]}" "${LIBWEBP_ROOT}"
+    make VERBOSE=1 -j
+    mkdir examples
+    case "${BUILD_TYPE}" in
+      static)
+        mkdir -p examples
+        cp [cd]webp examples
+        ;;
+      *) ;;  # Skip configuration
+    esac
+    exit 0
+    ;;
+  *)
+    log_err "Invalid TARGET"
+    usage
+    exit 1
+    ;;
+esac
+
+case "${TARGET}" in
+  *mingw32) ;;  # Skip configuration
+  *)
+    case "${TARGET}-${CC}" in
+      static-debug-gcc* | static-debug-)
+        CFLAGS="${CFLAGS} -fprofile-arcs -ftest-coverage -O0 -g"
+        CXXFLAGS="${CXXFLAGS} -fprofile-arcs -ftest-coverage -O0 -g"
+        export CFLAGS CXXFLAGS
+        ;;
+      *) ;;  # This case should not be reached.
+    esac
+    ;;
+esac
+
+setup_ccache
+
+cd "${LIBWEBP_ROOT}"
+./autogen.sh
+
+cd "${BUILD_DIR}"
+"${LIBWEBP_ROOT}/configure" \
+  --host "${TARGET}" --build "$("${LIBWEBP_ROOT}/config.guess")" \
+  --enable-everything "${config_flags[@]}"
+make -j V=1

infra/compile_android.sh

@@ -0,0 +1,224 @@
+#!/bin/bash
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+set -xe
+LIBWEBP_ROOT="$(realpath "$(dirname "$0")/..")"
+readonly LIBWEBP_ROOT
+readonly WORKSPACE=${WORKSPACE:-"$(mktemp -d -t webp.android.XXX)"}
+# shellcheck source=infra/common.sh
+source "${LIBWEBP_ROOT}/infra/common.sh"
+
+usage() {
+  cat << EOF
+Usage: $(basename "$0") BUILD_TYPE APP_ABI
+Options:
+BUILD_TYPE  supported build types:
+              static
+              static-debug
+              shared
+              shared-debug
+APP_ABI     supported application binary interfaces:
+              armeabi-v7a
+              arm64-v8a
+              x86
+              x86_64
+Environment variables:
+WORKSPACE   directory where the build is done.
+ANDROID_NDK_DIR directory where the android ndk tools are.
+EOF
+}
+
+################################################################################
+echo "Building libwebp for Android in ${WORKSPACE}"
+
+if [[ ! -d "${WORKSPACE}" ]]; then
+  log_err "${WORKSPACE} directory does not exist."
+  exit 1
+fi
+
+readonly BUILD_TYPE=${1:?"BUILD_TYPE is not defined.$(
+  echo
+  usage
+)"}
+readonly APP_ABI=${2:?"APP_ABI not defined.$(
+  echo
+  usage
+)"}
+readonly ANDROID_NDK_DIR=${ANDROID_NDK_DIR:?"ANDROID_NDK_DIR is not defined.$(
+  echo
+  usage
+)"}
+readonly BUILD_DIR="${WORKSPACE}/build-${BUILD_TYPE}"
+readonly STANDALONE_ANDROID_DIR="${WORKSPACE}/android"
+
+if [[ ! -x "${ANDROID_NDK_DIR}/ndk-build" ]]; then
+  log_err "unable to find ndk-build in ANDROID_NDK_DIR: ${ANDROID_NDK_DIR}."
+  exit 1
+fi
+
+CFLAGS=
+LDFLAGS=
+opts=()
+case "${BUILD_TYPE}" in
+  *debug)
+    readonly APP_OPTIM="debug"
+    CFLAGS="-O0 -g"
+    opts+=("--enable-asserts")
+    ;;
+  static* | shared*)
+    readonly APP_OPTIM="release"
+    CFLAGS="-O2 -g"
+    ;;
+  *)
+    usage
+    exit 1
+    ;;
+esac
+
+case "${BUILD_TYPE}" in
+  shared*) readonly SHARED="1" ;;
+  *)
+    readonly SHARED="0"
+    CFLAGS="${CFLAGS} -fPIE"
+    LDFLAGS="${LDFLAGS} -Wl,-pie"
+    opts+=("--disable-shared")
+    ;;
+esac
+
+# Create a fresh build directory
+make_build_dir "${BUILD_DIR}"
+cd "${BUILD_DIR}"
+ln -s "${LIBWEBP_ROOT}" jni
+
+"${ANDROID_NDK_DIR}/ndk-build" -j2 \
+  APP_ABI="${APP_ABI}" \
+  APP_OPTIM="${APP_OPTIM}" \
+  ENABLE_SHARED="${SHARED}"
+
+cd "${LIBWEBP_ROOT}"
+./autogen.sh
+
+case "${APP_ABI}" in
+  armeabi*) arch="arm" ;;
+  arm64*) arch="arm64" ;;
+  *) arch="${APP_ABI}" ;;
+esac
+# TODO(b/185520507): remove this and use the binaries from
+# toolchains/llvm/prebuilt/ directly.
+rm -rf "${STANDALONE_ANDROID_DIR}"
+"${ANDROID_NDK_DIR}/build/tools/make_standalone_toolchain.py" \
+  --api 24 --arch "${arch}" --stl gnustl --install-dir \
+  "${STANDALONE_ANDROID_DIR}"
+export PATH="${STANDALONE_ANDROID_DIR}/bin:${PATH}"
+
+rm -rf "${BUILD_DIR}"
+make_build_dir "${BUILD_DIR}"
+cd "${BUILD_DIR}"
+
+case "${arch}" in
+  arm)
+    host="arm-linux-androideabi"
+    case "${APP_ABI}" in
+      armeabi) ;;
+      armeabi-v7a)
+        CFLAGS="${CFLAGS} -march=armv7-a -mfpu=neon -mfloat-abi=softfp"
+        ;;
+      *) ;;  # No configuration needed
+    esac
+    ;;
+  arm64)
+    host="aarch64-linux-android"
+    ;;
+  x86)
+    host="i686-linux-android"
+    ;;
+  x86_64)
+    host="x86_64-linux-android"
+    ;;
+  *) ;;  # Skip configuration
+esac
+
+setup_ccache
+CC="clang"
+
+"${LIBWEBP_ROOT}/configure" --host "${host}" --build \
+  "$("${LIBWEBP_ROOT}/config.guess")" CC="${CC}" CFLAGS="${CFLAGS}" \
+  LDFLAGS="${LDFLAGS}" "${opts[@]}"
+make -j
+
+if [[ "${GERRIT_REFSPEC:-}" = "refs/heads/portable-intrinsics" ]] \
+  || [[ "${GERRIT_BRANCH:-}" = "portable-intrinsics" ]]; then
+  cd "${WORKSPACE}"
+  rm -rf build && mkdir build
+  cd build
+  standalone="${WORKSPACE}/android"
+  cmake ../libwebp \
+    -DWEBP_BUILD_DWEBP=1 \
+    -DCMAKE_C_COMPILER="${standalone}/bin/clang" \
+    -DCMAKE_PREFIX_PATH="${standalone}/sysroot/usr/lib" \
+    -DCMAKE_C_FLAGS=-fPIE \
+    -DCMAKE_EXE_LINKER_FLAGS=-Wl,-pie \
+    -DCMAKE_BUILD_TYPE=Release \
+    -DWEBP_ENABLE_WASM=1
+  make -j2
+
+  cd "${WORKSPACE}"
+  make_build_dir "${BUILD_DIR}"
+  cd "${BUILD_DIR}"
+  case "${APP_ABI}" in
+    armeabi-v7a | arm64*)
+      cmake "${LIBWEBP_ROOT}" \
+        -DWEBP_BUILD_DWEBP=1 \
+        -DCMAKE_C_COMPILER="${standalone}/bin/clang" \
+        -DCMAKE_PREFIX_PATH="${standalone}/sysroot/usr/lib" \
+        -DCMAKE_C_FLAGS='-fPIE -DENABLE_NEON_BUILTIN_MULHI_INT16X8' \
+        -DCMAKE_EXE_LINKER_FLAGS=-Wl,-pie \
+        -DCMAKE_BUILD_TYPE=Release \
+        -DWEBP_ENABLE_WASM=1
+      make -j2
+      ;;
+    x86*)
+      cmake "${LIBWEBP_ROOT}" \
+        -DWEBP_BUILD_DWEBP=1 \
+        -DCMAKE_C_COMPILER="${standalone}/bin/clang" \
+        -DCMAKE_PREFIX_PATH="${standalone}/sysroot/usr/lib" \
+        -DCMAKE_C_FLAGS='-fPIE -DENABLE_X86_BUILTIN_MULHI_INT16X8' \
+        -DCMAKE_EXE_LINKER_FLAGS=-Wl,-pie \
+        -DCMAKE_BUILD_TYPE=Release \
+        -DWEBP_ENABLE_WASM=1
+      make -j2
+      ;;
+    *)
+      log_err "APP_ABI not supported."
+      exit 1
+      ;;
+  esac
+fi

infra/compile_js.sh

@@ -0,0 +1,75 @@
+#!/bin/bash
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+set -ex
+
+readonly WORKSPACE="${WORKSPACE:-"$(mktemp -d -t webp.js.XXX)"}"
+readonly BUILD_DIR="${WORKSPACE}/webp_js/"
+readonly LIBWEBP_ROOT="$(realpath "$(dirname "$0")/..")"
+
+# shellcheck source=infra/common.sh
+source "${LIBWEBP_ROOT}/infra/common.sh"
+
+usage() {
+  cat << EOF
+Usage: $(basename "$0")
+Environment variables:
+WORKSPACE directory where the build is done
+EMSDK_DIR directory where emsdk is installed
+EOF
+}
+
+[[ -d "${EMSDK_DIR:?Not defined}" ]] \
+  || (log_err "${EMSDK_DIR} is not a valid directory." && exit 1)
+
+# shellcheck source=/opt/emsdk/emsdk_env.sh
+source "${EMSDK_DIR}/emsdk_env.sh"
+
+readonly EMSCRIPTEN=${EMSCRIPTEN:-"${EMSDK}/upstream/emscripten"}
+readonly \
+  EMSCRIPTEN_CMAKE_FILE="${EMSCRIPTEN}/cmake/Modules/Platform/Emscripten.cmake"
+make_build_dir "${BUILD_DIR}"
+
+pushd "${BUILD_DIR}"
+opts=("-GUnix Makefiles" "-DWEBP_BUILD_WEBP_JS=ON")
+if [[ -z "$(command -v emcmake)" ]]; then
+  opts+=("-DCMAKE_TOOLCHAIN_FILE=${EMSCRIPTEN_CMAKE_FILE}")
+  cmake \
+    "${opts[@]}" \
+    "${LIBWEBP_ROOT}"
+  make -j
+else
+  emcmake cmake \
+    "${opts[@]}" \
+    "${LIBWEBP_ROOT}"
+  emmake make -j
+fi
+popd

infra/run_static_analysis.sh

@@ -0,0 +1,98 @@
+#!/bin/bash
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+set -xe
+
+LIBWEBP_ROOT="$(realpath "$(dirname "$0")/..")"
+readonly LIBWEBP_ROOT
+readonly WORKSPACE=${WORKSPACE:-"$(mktemp -d -t webp.scanbuild.XXX)"}
+
+# shellcheck source=infra/common.sh
+source "${LIBWEBP_ROOT}/infra/common.sh"
+
+usage() {
+  cat << EOF
+Usage: $(basename "$0") MODE
+Options:
+MODE supported scan modes: (shallow|deep)
+Environment variables:
+WORKSPACE directory where the build is done.
+EOF
+}
+
+#######################################
+# Wrap clang-tools scan-build.
+# Globals:
+#   OUTPUT_DIR target directory where scan-build report is generated.
+#   MODE scan-build mode
+# Arguments:
+#   $* scan-build additional args.
+# Returns:
+#   scan-build retcode
+#######################################
+scan_build() {
+  scan-build -o "${OUTPUT_DIR}" --use-analyzer="$(command -v clang)" \
+    -analyzer-config mode="${MODE}" "$*"
+}
+
+MODE=${1:?"MODE is not specified.$(
+  echo
+  usage
+)"}
+
+readonly OUTPUT_DIR="${WORKSPACE}/output-${MODE}"
+readonly BUILD_DIR="${WORKSPACE}/build"
+
+make_build_dir "${OUTPUT_DIR}"
+make_build_dir "${BUILD_DIR}"
+
+cd "${LIBWEBP_ROOT}"
+./autogen.sh
+
+cd "${BUILD_DIR}"
+grep -m 1 -q 'enable-asserts' "${LIBWEBP_ROOT}/configure.ac" \
+    && args='--enable-asserts'
+scan_build "${LIBWEBP_ROOT}/configure" --enable-everything "${args}"
+scan_build make -j4
+
+index="$(find "${OUTPUT_DIR}" -name index.html)"
+if [[ -f "${index}" ]]; then
+  mv "$(dirname "${index}")/"* "${OUTPUT_DIR}"
+else
+  # make a empty report to wipe out any old bug reports.
+  cat << EOT > "${OUTPUT_DIR}/index.html"
+<html>
+<body>
+No bugs reported.
+</body>
+</html>
+EOT
+fi

iosbuild.sh

@@ -0,0 +1,168 @@
+#!/bin/bash
+#
+# This script generates 'WebP.framework' and 'WebPDecoder.framework',
+# 'WebPDemux.framework' and 'WebPMux.framework'.
+# An iOS app can decode WebP images by including 'WebPDecoder.framework' and
+# both encode and decode WebP images by including 'WebP.framework'.
+#
+# Run ./iosbuild.sh to generate the frameworks under the current directory
+# (the previous build will be erased if it exists).
+#
+# This script is inspired by the build script written by Carson McDonald.
+# (https://www.ioncannon.net/programming/1483/using-webp-to-reduce-native-ios-app-size/).
+
+set -e
+
+# Set this variable based on the desired minimum deployment target.
+readonly IOS_MIN_VERSION=6.0
+
+# Extract the latest SDK version from the final field of the form: iphoneosX.Y
+readonly SDK=$(xcodebuild -showsdks \
+  | grep iphoneos | sort | tail -n 1 | awk '{print substr($NF, 9)}'
+)
+# Extract Xcode version.
+readonly XCODE=$(xcodebuild -version | grep Xcode | cut -d " " -f2)
+if [[ -z "${XCODE}" ]]; then
+  echo "Xcode not available"
+  exit 1
+fi
+
+readonly OLDPATH=${PATH}
+
+# Add iPhoneOS-V6 to the list of platforms below if you need armv6 support.
+# Note that iPhoneOS-V6 support is not available with the iOS6 SDK.
+PLATFORMS="iPhoneSimulator iPhoneSimulator64"
+PLATFORMS+=" iPhoneOS-V7 iPhoneOS-V7s iPhoneOS-V7-arm64"
+readonly PLATFORMS
+readonly SRCDIR=$(dirname $0)
+readonly TOPDIR=$(pwd)
+readonly BUILDDIR="${TOPDIR}/iosbuild"
+readonly TARGETDIR="${TOPDIR}/WebP.framework"
+readonly DECTARGETDIR="${TOPDIR}/WebPDecoder.framework"
+readonly MUXTARGETDIR="${TOPDIR}/WebPMux.framework"
+readonly DEMUXTARGETDIR="${TOPDIR}/WebPDemux.framework"
+readonly DEVELOPER=$(xcode-select --print-path)
+readonly PLATFORMSROOT="${DEVELOPER}/Platforms"
+readonly LIPO=$(xcrun -sdk iphoneos${SDK} -find lipo)
+LIBLIST=''
+DECLIBLIST=''
+MUXLIBLIST=''
+DEMUXLIBLIST=''
+
+if [[ -z "${SDK}" ]]; then
+  echo "iOS SDK not available"
+  exit 1
+elif [[ ${SDK%%.*} -gt 8 ]]; then
+  EXTRA_CFLAGS="-fembed-bitcode"
+elif [[ ${SDK%%.*} -le 6 ]]; then
+  echo "You need iOS SDK version 6.0 or above"
+  exit 1
+fi
+
+echo "Xcode Version: ${XCODE}"
+echo "iOS SDK Version: ${SDK}"
+
+if [[ -e "${BUILDDIR}" || -e "${TARGETDIR}" || -e "${DECTARGETDIR}" \
+      || -e "${MUXTARGETDIR}" || -e "${DEMUXTARGETDIR}" ]]; then
+  cat << EOF
+WARNING: The following directories will be deleted:
+WARNING:   ${BUILDDIR}
+WARNING:   ${TARGETDIR}
+WARNING:   ${DECTARGETDIR}
+WARNING:   ${MUXTARGETDIR}
+WARNING:   ${DEMUXTARGETDIR}
+WARNING: The build will continue in 5 seconds...
+EOF
+  sleep 5
+fi
+rm -rf ${BUILDDIR} ${TARGETDIR} ${DECTARGETDIR} \
+    ${MUXTARGETDIR} ${DEMUXTARGETDIR}
+mkdir -p ${BUILDDIR} ${TARGETDIR}/Headers/ ${DECTARGETDIR}/Headers/ \
+    ${MUXTARGETDIR}/Headers/ ${DEMUXTARGETDIR}/Headers/
+
+if [[ ! -e ${SRCDIR}/configure ]]; then
+  if ! (cd ${SRCDIR} && sh autogen.sh); then
+    cat << EOF
+Error creating configure script!
+This script requires the autoconf/automake and libtool to build. MacPorts can
+be used to obtain these:
+https://www.macports.org/install.php
+EOF
+    exit 1
+  fi
+fi
+
+for PLATFORM in ${PLATFORMS}; do
+  ARCH2=""
+  if [[ "${PLATFORM}" == "iPhoneOS-V7-arm64" ]]; then
+    PLATFORM="iPhoneOS"
+    ARCH="aarch64"
+    ARCH2="arm64"
+  elif [[ "${PLATFORM}" == "iPhoneOS-V7s" ]]; then
+    PLATFORM="iPhoneOS"
+    ARCH="armv7s"
+  elif [[ "${PLATFORM}" == "iPhoneOS-V7" ]]; then
+    PLATFORM="iPhoneOS"
+    ARCH="armv7"
+  elif [[ "${PLATFORM}" == "iPhoneOS-V6" ]]; then
+    PLATFORM="iPhoneOS"
+    ARCH="armv6"
+  elif [[ "${PLATFORM}" == "iPhoneSimulator64" ]]; then
+    PLATFORM="iPhoneSimulator"
+    ARCH="x86_64"
+  else
+    ARCH="i386"
+  fi
+
+  ROOTDIR="${BUILDDIR}/${PLATFORM}-${SDK}-${ARCH}"
+  mkdir -p "${ROOTDIR}"
+
+  DEVROOT="${DEVELOPER}/Toolchains/XcodeDefault.xctoolchain"
+  SDKROOT="${PLATFORMSROOT}/"
+  SDKROOT+="${PLATFORM}.platform/Developer/SDKs/${PLATFORM}${SDK}.sdk/"
+  CFLAGS="-arch ${ARCH2:-${ARCH}} -pipe -isysroot ${SDKROOT} -O3 -DNDEBUG"
+  CFLAGS+=" -miphoneos-version-min=${IOS_MIN_VERSION} ${EXTRA_CFLAGS}"
+
+  set -x
+  export PATH="${DEVROOT}/usr/bin:${OLDPATH}"
+  ${SRCDIR}/configure --host=${ARCH}-apple-darwin --prefix=${ROOTDIR} \
+    --build=$(${SRCDIR}/config.guess) \
+    --disable-shared --enable-static \
+    --enable-libwebpdecoder --enable-swap-16bit-csp \
+    --enable-libwebpmux \
+    CFLAGS="${CFLAGS}"
+  set +x
+
+  # Build only the libraries, skip the examples.
+  make V=0 -C sharpyuv
+  make V=0 -C src install
+
+  LIBLIST+=" ${ROOTDIR}/lib/libwebp.a"
+  DECLIBLIST+=" ${ROOTDIR}/lib/libwebpdecoder.a"
+  MUXLIBLIST+=" ${ROOTDIR}/lib/libwebpmux.a"
+  DEMUXLIBLIST+=" ${ROOTDIR}/lib/libwebpdemux.a"
+
+  make clean
+
+  export PATH=${OLDPATH}
+done
+
+echo "LIBLIST = ${LIBLIST}"
+cp -a ${SRCDIR}/src/webp/{decode,encode,types}.h ${TARGETDIR}/Headers/
+${LIPO} -create ${LIBLIST} -output ${TARGETDIR}/WebP
+
+echo "DECLIBLIST = ${DECLIBLIST}"
+cp -a ${SRCDIR}/src/webp/{decode,types}.h ${DECTARGETDIR}/Headers/
+${LIPO} -create ${DECLIBLIST} -output ${DECTARGETDIR}/WebPDecoder
+
+echo "MUXLIBLIST = ${MUXLIBLIST}"
+cp -a ${SRCDIR}/src/webp/{types,mux,mux_types}.h \
+    ${MUXTARGETDIR}/Headers/
+${LIPO} -create ${MUXLIBLIST} -output ${MUXTARGETDIR}/WebPMux
+
+echo "DEMUXLIBLIST = ${DEMUXLIBLIST}"
+cp -a ${SRCDIR}/src/webp/{decode,types,mux_types,demux}.h \
+    ${DEMUXTARGETDIR}/Headers/
+${LIPO} -create ${DEMUXLIBLIST} -output ${DEMUXTARGETDIR}/WebPDemux
+
+echo  "SUCCESS"

m4/.gitignore

@@ -0,0 +1,2 @@
+/libtool.m4
+/lt*.m4

m4/ax_pthread.m4

@@ -0,0 +1,332 @@
+# ===========================================================================
+#        http://www.gnu.org/software/autoconf-archive/ax_pthread.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
+#
+# DESCRIPTION
+#
+#   This macro figures out how to build C programs using POSIX threads. It
+#   sets the PTHREAD_LIBS output variable to the threads library and linker
+#   flags, and the PTHREAD_CFLAGS output variable to any special C compiler
+#   flags that are needed. (The user can also force certain compiler
+#   flags/libs to be tested by setting these environment variables.)
+#
+#   Also sets PTHREAD_CC to any special C compiler that is needed for
+#   multi-threaded programs (defaults to the value of CC otherwise). (This
+#   is necessary on AIX to use the special cc_r compiler alias.)
+#
+#   NOTE: You are assumed to not only compile your program with these flags,
+#   but also link it with them as well. e.g. you should link with
+#   $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
+#
+#   If you are only building threads programs, you may wish to use these
+#   variables in your default LIBS, CFLAGS, and CC:
+#
+#     LIBS="$PTHREAD_LIBS $LIBS"
+#     CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+#     CC="$PTHREAD_CC"
+#
+#   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
+#   has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to that name
+#   (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
+#
+#   Also HAVE_PTHREAD_PRIO_INHERIT is defined if pthread is found and the
+#   PTHREAD_PRIO_INHERIT symbol is defined when compiling with
+#   PTHREAD_CFLAGS.
+#
+#   ACTION-IF-FOUND is a list of shell commands to run if a threads library
+#   is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it
+#   is not found. If ACTION-IF-FOUND is not specified, the default action
+#   will define HAVE_PTHREAD.
+#
+#   Please let the authors know if this macro fails on any platform, or if
+#   you have any other suggestions or comments. This macro was based on work
+#   by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help
+#   from M. Frigo), as well as ac_pthread and hb_pthread macros posted by
+#   Alejandro Forero Cuervo to the autoconf macro repository. We are also
+#   grateful for the helpful feedback of numerous users.
+#
+#   Updated for Autoconf 2.68 by Daniel Richard G.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
+#   Copyright (c) 2011 Daniel Richard G. <skunk@iSKUNK.ORG>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 21
+
+AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
+AC_DEFUN([AX_PTHREAD], [
+AC_REQUIRE([AC_CANONICAL_HOST])
+AC_LANG_PUSH([C])
+ax_pthread_ok=no
+
+# We used to check for pthread.h first, but this fails if pthread.h
+# requires special compiler flags (e.g. on True64 or Sequent).
+# It gets checked for in the link test anyway.
+
+# First of all, check if the user has set any of the PTHREAD_LIBS,
+# etcetera environment variables, and if threads linking works using
+# them:
+if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
+        save_CFLAGS="$CFLAGS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+        save_LIBS="$LIBS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+        AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
+        AC_TRY_LINK_FUNC([pthread_join], [ax_pthread_ok=yes])
+        AC_MSG_RESULT([$ax_pthread_ok])
+        if test x"$ax_pthread_ok" = xno; then
+                PTHREAD_LIBS=""
+                PTHREAD_CFLAGS=""
+        fi
+        LIBS="$save_LIBS"
+        CFLAGS="$save_CFLAGS"
+fi
+
+# We must check for the threads library under a number of different
+# names; the ordering is very important because some systems
+# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
+# libraries is broken (non-POSIX).
+
+# Create a list of thread flags to try.  Items starting with a "-" are
+# C compiler flags, and other items are library names, except for "none"
+# which indicates that we try without any flags at all, and "pthread-config"
+# which is a program returning the flags for the Pth emulation library.
+
+ax_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
+
+# The ordering *is* (sometimes) important.  Some notes on the
+# individual items follow:
+
+# pthreads: AIX (must check this before -lpthread)
+# none: in case threads are in libc; should be tried before -Kthread and
+#       other compiler flags to prevent continual compiler warnings
+# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
+# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
+# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
+# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
+# -pthreads: Solaris/gcc
+# -mthreads: Mingw32/gcc, Lynx/gcc
+# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
+#      doesn't hurt to check since this sometimes defines pthreads too;
+#      also defines -D_REENTRANT)
+#      ... -mt is also the pthreads flag for HP/aCC
+# pthread: Linux, etcetera
+# --thread-safe: KAI C++
+# pthread-config: use pthread-config program (for GNU Pth library)
+
+case ${host_os} in
+        solaris*)
+
+        # On Solaris (at least, for some versions), libc contains stubbed
+        # (non-functional) versions of the pthreads routines, so link-based
+        # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
+        # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
+        # a function called by this macro, so we could check for that, but
+        # who knows whether they'll stub that too in a future libc.)  So,
+        # we'll just look for -pthreads and -lpthread first:
+
+        ax_pthread_flags="-pthreads pthread -mt -pthread $ax_pthread_flags"
+        ;;
+
+        darwin*)
+        ax_pthread_flags="-pthread $ax_pthread_flags"
+        ;;
+esac
+
+# Clang doesn't consider unrecognized options an error unless we specify
+# -Werror. We throw in some extra Clang-specific options to ensure that
+# this doesn't happen for GCC, which also accepts -Werror.
+
+AC_MSG_CHECKING([if compiler needs -Werror to reject unknown flags])
+save_CFLAGS="$CFLAGS"
+ax_pthread_extra_flags="-Werror"
+CFLAGS="$CFLAGS $ax_pthread_extra_flags -Wunknown-warning-option -Wsizeof-array-argument"
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([int foo(void);],[foo()])],
+                  [AC_MSG_RESULT([yes])],
+                  [ax_pthread_extra_flags=
+                   AC_MSG_RESULT([no])])
+CFLAGS="$save_CFLAGS"
+
+if test x"$ax_pthread_ok" = xno; then
+for flag in $ax_pthread_flags; do
+
+        case $flag in
+                none)
+                AC_MSG_CHECKING([whether pthreads work without any flags])
+                ;;
+
+                -*)
+                AC_MSG_CHECKING([whether pthreads work with $flag])
+                PTHREAD_CFLAGS="$flag"
+                ;;
+
+                pthread-config)
+                AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
+                if test x"$ax_pthread_config" = xno; then continue; fi
+                PTHREAD_CFLAGS="`pthread-config --cflags`"
+                PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
+                ;;
+
+                *)
+                AC_MSG_CHECKING([for the pthreads library -l$flag])
+                PTHREAD_LIBS="-l$flag"
+                ;;
+        esac
+
+        save_LIBS="$LIBS"
+        save_CFLAGS="$CFLAGS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS $ax_pthread_extra_flags"
+
+        # Check for various functions.  We must include pthread.h,
+        # since some functions may be macros.  (On the Sequent, we
+        # need a special flag -Kthread to make this header compile.)
+        # We check for pthread_join because it is in -lpthread on IRIX
+        # while pthread_create is in libc.  We check for pthread_attr_init
+        # due to DEC craziness with -lpthreads.  We check for
+        # pthread_cleanup_push because it is one of the few pthread
+        # functions on Solaris that doesn't have a non-functional libc stub.
+        # We try pthread_create on general principles.
+        AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
+                        static void routine(void *a) { a = 0; }
+                        static void *start_routine(void *a) { return a; }],
+                       [pthread_t th; pthread_attr_t attr;
+                        pthread_create(&th, 0, start_routine, 0);
+                        pthread_join(th, 0);
+                        pthread_attr_init(&attr);
+                        pthread_cleanup_push(routine, 0);
+                        pthread_cleanup_pop(0) /* ; */])],
+                [ax_pthread_ok=yes],
+                [])
+
+        LIBS="$save_LIBS"
+        CFLAGS="$save_CFLAGS"
+
+        AC_MSG_RESULT([$ax_pthread_ok])
+        if test "x$ax_pthread_ok" = xyes; then
+                break;
+        fi
+
+        PTHREAD_LIBS=""
+        PTHREAD_CFLAGS=""
+done
+fi
+
+# Various other checks:
+if test "x$ax_pthread_ok" = xyes; then
+        save_LIBS="$LIBS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+        save_CFLAGS="$CFLAGS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+
+        # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
+        AC_MSG_CHECKING([for joinable pthread attribute])
+        attr_name=unknown
+        for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
+            AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
+                           [int attr = $attr; return attr /* ; */])],
+                [attr_name=$attr; break],
+                [])
+        done
+        AC_MSG_RESULT([$attr_name])
+        if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
+            AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE], [$attr_name],
+                               [Define to necessary symbol if this constant
+                                uses a non-standard name on your system.])
+        fi
+
+        AC_MSG_CHECKING([if more special flags are required for pthreads])
+        flag=no
+        case ${host_os} in
+            aix* | freebsd* | darwin*) flag="-D_THREAD_SAFE";;
+            osf* | hpux*) flag="-D_REENTRANT";;
+            solaris*)
+            if test "$GCC" = "yes"; then
+                flag="-D_REENTRANT"
+            else
+                # TODO: What about Clang on Solaris?
+                flag="-mt -D_REENTRANT"
+            fi
+            ;;
+        esac
+        AC_MSG_RESULT([$flag])
+        if test "x$flag" != xno; then
+            PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
+        fi
+
+        AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
+            [ax_cv_PTHREAD_PRIO_INHERIT], [
+                AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
+                                                [[int i = PTHREAD_PRIO_INHERIT;]])],
+                    [ax_cv_PTHREAD_PRIO_INHERIT=yes],
+                    [ax_cv_PTHREAD_PRIO_INHERIT=no])
+            ])
+        AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes"],
+            [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.])])
+
+        LIBS="$save_LIBS"
+        CFLAGS="$save_CFLAGS"
+
+        # More AIX lossage: compile with *_r variant
+        if test "x$GCC" != xyes; then
+            case $host_os in
+                aix*)
+                AS_CASE(["x/$CC"],
+                  [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
+                  [#handle absolute path differently from PATH based program lookup
+                   AS_CASE(["x$CC"],
+                     [x/*],
+                     [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
+                     [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
+                ;;
+            esac
+        fi
+fi
+
+test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
+
+AC_SUBST([PTHREAD_LIBS])
+AC_SUBST([PTHREAD_CFLAGS])
+AC_SUBST([PTHREAD_CC])
+
+# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
+if test x"$ax_pthread_ok" = xyes; then
+        ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1])
+        :
+else
+        ax_pthread_ok=no
+        $2
+fi
+AC_LANG_POP
+])dnl AX_PTHREAD