tomato/toxcore/ccompat.h
Green Sky 227425b90e Squashed 'external/toxcore/c-toxcore/' content from commit 67badf69
git-subtree-dir: external/toxcore/c-toxcore
git-subtree-split: 67badf69416a74e74f6d7eb51dd96f37282b8455
2023-07-25 11:53:09 +02:00

88 lines
2.5 KiB
C

/* SPDX-License-Identifier: GPL-3.0-or-later
* Copyright © 2016-2021 The TokTok team.
*/
/**
* C language compatibility macros for varying compiler support.
*/
#ifndef C_TOXCORE_TOXCORE_CCOMPAT_H
#define C_TOXCORE_TOXCORE_CCOMPAT_H
#include <stddef.h> // NULL, size_t
#include "attributes.h"
//!TOKSTYLE-
// Variable length arrays.
// VLA(type, name, size) allocates a variable length array with automatic
// storage duration. VLA_SIZE(name) evaluates to the runtime size of that array
// in bytes.
//
// If C99 VLAs are not available, an emulation using alloca (stack allocation
// "function") is used. Note the semantic difference: alloca'd memory does not
// get freed at the end of the declaration's scope. Do not use VLA() in loops or
// you may run out of stack space.
#if !defined(DISABLE_VLA) && !defined(_MSC_VER) && defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
// C99 VLAs.
#define ALLOC_VLA(type, name, size) type name[size]
#define SIZEOF_VLA sizeof
#else
// Emulation using alloca.
#ifdef _WIN32
#include <malloc.h>
#elif defined(__COMPCERT__)
// TODO(iphydf): This leaks memory like crazy, so compcert is useless for now.
// Once we're rid of VLAs, we can remove this and compcert becomes useful.
#define alloca malloc
#include <stdlib.h>
#elif defined(__linux__)
#include <alloca.h>
#else
#include <stdlib.h>
#if !defined(alloca) && defined(__GNUC__)
#define alloca __builtin_alloca
#endif
#endif
#define ALLOC_VLA(type, name, size) \
const size_t name##_vla_size = (size) * sizeof(type); \
type *const name = (type *)alloca(name##_vla_size)
#define SIZEOF_VLA(name) name##_vla_size
#endif
#ifdef MAX_VLA_SIZE
#include <assert.h>
#define VLA(type, name, size) \
ALLOC_VLA(type, name, size); \
assert((size_t)(size) * sizeof(type) <= MAX_VLA_SIZE)
#else
#define VLA ALLOC_VLA
#endif
#if !defined(__cplusplus) || __cplusplus < 201103L
#define nullptr NULL
#ifndef static_assert
#ifdef __GNUC__
// We'll just assume gcc and clang support C11 _Static_assert.
#define static_assert _Static_assert
#else // !__GNUC__
#define STATIC_ASSERT_(cond, msg, line) typedef int static_assert_##line[(cond) ? 1 : -1]
#define STATIC_ASSERT(cond, msg, line) STATIC_ASSERT_(cond, msg, line)
#define static_assert(cond, msg) STATIC_ASSERT(cond, msg, __LINE__)
#endif // !__GNUC__
#endif // !static_assert
#endif // !__cplusplus
#ifdef __GNUC__
#define GNU_PRINTF(f, a) __attribute__((__format__(__printf__, f, a)))
#else
#define GNU_PRINTF(f, a)
#endif
//!TOKSTYLE+
#endif // C_TOXCORE_TOXCORE_CCOMPAT_H