Style: Remove trailing whitespaces

This commit is contained in:
Jules Maselbas 2021-12-25 16:43:37 +01:00
parent c04a975e00
commit b060b961e8

94
qoi.h
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@ -28,8 +28,8 @@ SOFTWARE.
-- About -- About
QOI encodes and decodes images in a lossless format. Compared to stb_image and QOI encodes and decodes images in a lossless format. Compared to stb_image and
stb_image_write QOI offers 20x-50x faster encoding, 3x-4x faster decoding and stb_image_write QOI offers 20x-50x faster encoding, 3x-4x faster decoding and
20% better compression. 20% better compression.
@ -45,7 +45,7 @@ stb_image_write QOI offers 20x-50x faster encoding, 3x-4x faster decoding and
// the input pixel data. // the input pixel data.
qoi_write("image_new.qoi", rgba_pixels, &(qoi_desc){ qoi_write("image_new.qoi", rgba_pixels, &(qoi_desc){
.width = 1920, .width = 1920,
.height = 1080, .height = 1080,
.channels = 4, .channels = 4,
.colorspace = QOI_SRGB .colorspace = QOI_SRGB
}); });
@ -74,7 +74,7 @@ QOI_NO_STDIO before including this library.
This library uses malloc() and free(). To supply your own malloc implementation This library uses malloc() and free(). To supply your own malloc implementation
you can define QOI_MALLOC and QOI_FREE before including this library. you can define QOI_MALLOC and QOI_FREE before including this library.
This library uses memset() to zero-initialize the index. To supply your own This library uses memset() to zero-initialize the index. To supply your own
implementation you can define QOI_ZEROARR before including this library. implementation you can define QOI_ZEROARR before including this library.
@ -91,8 +91,8 @@ struct qoi_header_t {
uint8_t colorspace; // 0 = sRGB with linear alpha, 1 = all channels linear uint8_t colorspace; // 0 = sRGB with linear alpha, 1 = all channels linear
}; };
Images are encoded row by row, left to right, top to bottom. The decoder and Images are encoded row by row, left to right, top to bottom. The decoder and
encoder start with {r: 0, g: 0, b: 0, a: 255} as the previous pixel value. An encoder start with {r: 0, g: 0, b: 0, a: 255} as the previous pixel value. An
image is complete when all pixels specified by width * height have been covered. image is complete when all pixels specified by width * height have been covered.
Pixels are encoded as Pixels are encoded as
@ -101,20 +101,20 @@ Pixels are encoded as
- a difference to the previous pixel value in r,g,b - a difference to the previous pixel value in r,g,b
- full r,g,b or r,g,b,a values - full r,g,b or r,g,b,a values
The color channels are assumed to not be premultiplied with the alpha channel The color channels are assumed to not be premultiplied with the alpha channel
("un-premultiplied alpha"). ("un-premultiplied alpha").
A running array[64] (zero-initialized) of previously seen pixel values is A running array[64] (zero-initialized) of previously seen pixel values is
maintained by the encoder and decoder. Each pixel that is seen by the encoder maintained by the encoder and decoder. Each pixel that is seen by the encoder
and decoder is put into this array at the position formed by a hash function of and decoder is put into this array at the position formed by a hash function of
the color value. In the encoder, if the pixel value at the index matches the the color value. In the encoder, if the pixel value at the index matches the
current pixel, this index position is written to the stream as QOI_OP_INDEX. current pixel, this index position is written to the stream as QOI_OP_INDEX.
The hash function for the index is: The hash function for the index is:
index_position = (r * 3 + g * 5 + b * 7 + a * 11) % 64 index_position = (r * 3 + g * 5 + b * 7 + a * 11) % 64
Each chunk starts with a 2- or 8-bit tag, followed by a number of data bits. The Each chunk starts with a 2- or 8-bit tag, followed by a number of data bits. The
bit length of chunks is divisible by 8 - i.e. all chunks are byte aligned. All bit length of chunks is divisible by 8 - i.e. all chunks are byte aligned. All
values encoded in these data bits have the most significant bit on the left. values encoded in these data bits have the most significant bit on the left.
The 8-bit tags have precedence over the 2-bit tags. A decoder must check for the The 8-bit tags have precedence over the 2-bit tags. A decoder must check for the
@ -136,10 +136,10 @@ The possible chunks are:
6-bit index into the color index array: 0..63 6-bit index into the color index array: 0..63
A valid encoder must not issue 7 or more consecutive QOI_OP_INDEX chunks to the A valid encoder must not issue 7 or more consecutive QOI_OP_INDEX chunks to the
index 0, to avoid confusion with the 8 byte end marker. index 0, to avoid confusion with the 8 byte end marker.
.- QOI_OP_DIFF -----------. .- QOI_OP_DIFF -----------.
| Byte[0] | | Byte[0] |
| 7 6 5 4 3 2 1 0 | | 7 6 5 4 3 2 1 0 |
|-------+-----+-----+-----| |-------+-----+-----+-----|
@ -150,16 +150,16 @@ index 0, to avoid confusion with the 8 byte end marker.
2-bit green channel difference from the previous pixel between -2..1 2-bit green channel difference from the previous pixel between -2..1
2-bit blue channel difference from the previous pixel between -2..1 2-bit blue channel difference from the previous pixel between -2..1
The difference to the current channel values are using a wraparound operation, The difference to the current channel values are using a wraparound operation,
so "1 - 2" will result in 255, while "255 + 1" will result in 0. so "1 - 2" will result in 255, while "255 + 1" will result in 0.
Values are stored as unsigned integers with a bias of 2. E.g. -2 is stored as Values are stored as unsigned integers with a bias of 2. E.g. -2 is stored as
0 (b00). 1 is stored as 3 (b11). 0 (b00). 1 is stored as 3 (b11).
The alpha value remains unchanged from the previous pixel. The alpha value remains unchanged from the previous pixel.
.- QOI_OP_LUMA -------------------------------------. .- QOI_OP_LUMA -------------------------------------.
| Byte[0] | Byte[1] | | Byte[0] | Byte[1] |
| 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 | | 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 |
|-------+-----------------+-------------+-----------| |-------+-----------------+-------------+-----------|
@ -170,16 +170,16 @@ The alpha value remains unchanged from the previous pixel.
4-bit red channel difference minus green channel difference -8..7 4-bit red channel difference minus green channel difference -8..7
4-bit blue channel difference minus green channel difference -8..7 4-bit blue channel difference minus green channel difference -8..7
The green channel is used to indicate the general direction of change and is The green channel is used to indicate the general direction of change and is
encoded in 6 bits. The red and blue channels (dr and db) base their diffs off encoded in 6 bits. The red and blue channels (dr and db) base their diffs off
of the green channel difference and are encoded in 4 bits. I.e.: of the green channel difference and are encoded in 4 bits. I.e.:
dr_dg = (last_px.r - cur_px.r) - (last_px.g - cur_px.g) dr_dg = (last_px.r - cur_px.r) - (last_px.g - cur_px.g)
db_dg = (last_px.b - cur_px.b) - (last_px.g - cur_px.g) db_dg = (last_px.b - cur_px.b) - (last_px.g - cur_px.g)
The difference to the current channel values are using a wraparound operation, The difference to the current channel values are using a wraparound operation,
so "10 - 13" will result in 253, while "250 + 7" will result in 1. so "10 - 13" will result in 253, while "250 + 7" will result in 1.
Values are stored as unsigned integers with a bias of 32 for the green channel Values are stored as unsigned integers with a bias of 32 for the green channel
and a bias of 8 for the red and blue channel. and a bias of 8 for the red and blue channel.
The alpha value remains unchanged from the previous pixel. The alpha value remains unchanged from the previous pixel.
@ -194,8 +194,8 @@ The alpha value remains unchanged from the previous pixel.
2-bit tag b11 2-bit tag b11
6-bit run-length repeating the previous pixel: 1..62 6-bit run-length repeating the previous pixel: 1..62
The run-length is stored with a bias of -1. Note that the run-lengths 63 and 64 The run-length is stored with a bias of -1. Note that the run-lengths 63 and 64
(b111110 and b111111) are illegal as they are occupied by the QOI_OP_RGB and (b111110 and b111111) are illegal as they are occupied by the QOI_OP_RGB and
QOI_OP_RGBA tags. QOI_OP_RGBA tags.
@ -238,15 +238,15 @@ Header - Public functions */
extern "C" { extern "C" {
#endif #endif
/* A pointer to a qoi_desc struct has to be supplied to all of qoi's functions. /* A pointer to a qoi_desc struct has to be supplied to all of qoi's functions.
It describes either the input format (for qoi_write and qoi_encode), or is It describes either the input format (for qoi_write and qoi_encode), or is
filled with the description read from the file header (for qoi_read and filled with the description read from the file header (for qoi_read and
qoi_decode). qoi_decode).
The colorspace in this qoi_desc is an enum where The colorspace in this qoi_desc is an enum where
0 = sRGB, i.e. gamma scaled RGB channels and a linear alpha channel 0 = sRGB, i.e. gamma scaled RGB channels and a linear alpha channel
1 = all channels are linear 1 = all channels are linear
You may use the constants QOI_SRGB or QOI_LINEAR. The colorspace is purely You may use the constants QOI_SRGB or QOI_LINEAR. The colorspace is purely
informative. It will be saved to the file header, but does not affect informative. It will be saved to the file header, but does not affect
en-/decoding in any way. */ en-/decoding in any way. */
@ -262,11 +262,11 @@ typedef struct {
#ifndef QOI_NO_STDIO #ifndef QOI_NO_STDIO
/* Encode raw RGB or RGBA pixels into a QOI image and write it to the file /* Encode raw RGB or RGBA pixels into a QOI image and write it to the file
system. The qoi_desc struct must be filled with the image width, height, system. The qoi_desc struct must be filled with the image width, height,
number of channels (3 = RGB, 4 = RGBA) and the colorspace. number of channels (3 = RGB, 4 = RGBA) and the colorspace.
The function returns 0 on failure (invalid parameters, or fopen or malloc The function returns 0 on failure (invalid parameters, or fopen or malloc
failed) or the number of bytes written on success. */ failed) or the number of bytes written on success. */
int qoi_write(const char *filename, const void *data, const qoi_desc *desc); int qoi_write(const char *filename, const void *data, const qoi_desc *desc);
@ -277,7 +277,7 @@ number of channels from the file header is used. If channels is 3 or 4 the
output format will be forced into this number of channels. output format will be forced into this number of channels.
The function either returns NULL on failure (invalid data, or malloc or fopen The function either returns NULL on failure (invalid data, or malloc or fopen
failed) or a pointer to the decoded pixels. On success, the qoi_desc struct failed) or a pointer to the decoded pixels. On success, the qoi_desc struct
will be filled with the description from the file header. will be filled with the description from the file header.
The returned pixel data should be free()d after use. */ The returned pixel data should be free()d after use. */
@ -289,8 +289,8 @@ void *qoi_read(const char *filename, qoi_desc *desc, int channels);
/* Encode raw RGB or RGBA pixels into a QOI image in memory. /* Encode raw RGB or RGBA pixels into a QOI image in memory.
The function either returns NULL on failure (invalid parameters or malloc The function either returns NULL on failure (invalid parameters or malloc
failed) or a pointer to the encoded data on success. On success the out_len failed) or a pointer to the encoded data on success. On success the out_len
is set to the size in bytes of the encoded data. is set to the size in bytes of the encoded data.
The returned qoi data should be free()d after use. */ The returned qoi data should be free()d after use. */
@ -300,8 +300,8 @@ void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len);
/* Decode a QOI image from memory. /* Decode a QOI image from memory.
The function either returns NULL on failure (invalid parameters or malloc The function either returns NULL on failure (invalid parameters or malloc
failed) or a pointer to the decoded pixels. On success, the qoi_desc struct failed) or a pointer to the decoded pixels. On success, the qoi_desc struct
is filled with the description from the file header. is filled with the description from the file header.
The returned pixel data should be free()d after use. */ The returned pixel data should be free()d after use. */
@ -346,8 +346,8 @@ Implementation */
#define QOI_HEADER_SIZE 14 #define QOI_HEADER_SIZE 14
/* 2GB is the max file size that this implementation can safely handle. We guard /* 2GB is the max file size that this implementation can safely handle. We guard
against anything larger than that, assuming the worst case with 5 bytes per against anything larger than that, assuming the worst case with 5 bytes per
pixel, rounded down to a nice clean value. 400 million pixels ought to be pixel, rounded down to a nice clean value. 400 million pixels ought to be
enough for anybody. */ enough for anybody. */
#define QOI_PIXELS_MAX ((unsigned int)400000000) #define QOI_PIXELS_MAX ((unsigned int)400000000)
@ -391,8 +391,8 @@ void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len) {
return NULL; return NULL;
} }
max_size = max_size =
desc->width * desc->height * (desc->channels + 1) + desc->width * desc->height * (desc->channels + 1) +
QOI_HEADER_SIZE + sizeof(qoi_padding); QOI_HEADER_SIZE + sizeof(qoi_padding);
p = 0; p = 0;
@ -418,7 +418,7 @@ void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len) {
px_prev.rgba.b = 0; px_prev.rgba.b = 0;
px_prev.rgba.a = 255; px_prev.rgba.a = 255;
px = px_prev; px = px_prev;
px_len = desc->width * desc->height * desc->channels; px_len = desc->width * desc->height * desc->channels;
px_end = px_len - desc->channels; px_end = px_len - desc->channels;
channels = desc->channels; channels = desc->channels;
@ -466,14 +466,14 @@ void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len) {
if ( if (
vr > -3 && vr < 2 && vr > -3 && vr < 2 &&
vg > -3 && vg < 2 && vg > -3 && vg < 2 &&
vb > -3 && vb < 2 vb > -3 && vb < 2
) { ) {
bytes[p++] = QOI_OP_DIFF | (vr + 2) << 4 | (vg + 2) << 2 | (vb + 2); bytes[p++] = QOI_OP_DIFF | (vr + 2) << 4 | (vg + 2) << 2 | (vb + 2);
} }
else if ( else if (
vg_r > -9 && vg_r < 8 && vg_r > -9 && vg_r < 8 &&
vg > -33 && vg < 32 && vg > -33 && vg < 32 &&
vg_b > -9 && vg_b < 8 vg_b > -9 && vg_b < 8
) { ) {
bytes[p++] = QOI_OP_LUMA | (vg + 32); bytes[p++] = QOI_OP_LUMA | (vg + 32);
@ -532,7 +532,7 @@ void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels) {
desc->colorspace = bytes[p++]; desc->colorspace = bytes[p++];
if ( if (
desc->width == 0 || desc->height == 0 || desc->width == 0 || desc->height == 0 ||
desc->channels < 3 || desc->channels > 4 || desc->channels < 3 || desc->channels > 4 ||
desc->colorspace > 1 || desc->colorspace > 1 ||
header_magic != QOI_MAGIC || header_magic != QOI_MAGIC ||
@ -598,7 +598,7 @@ void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels) {
index[QOI_COLOR_HASH(px) % 64] = px; index[QOI_COLOR_HASH(px) % 64] = px;
} }
if (channels == 4) { if (channels == 4) {
*(qoi_rgba_t*)(pixels + px_pos) = px; *(qoi_rgba_t*)(pixels + px_pos) = px;
} }
else { else {
@ -627,11 +627,11 @@ int qoi_write(const char *filename, const void *data, const qoi_desc *desc) {
if (!encoded) { if (!encoded) {
fclose(f); fclose(f);
return 0; return 0;
} }
fwrite(encoded, 1, size, f); fwrite(encoded, 1, size, f);
fclose(f); fclose(f);
QOI_FREE(encoded); QOI_FREE(encoded);
return size; return size;
} }