/* * copyright (c) 2006 Michael Niedermayer * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * memory handling functions */ #ifndef AVUTIL_MEM_H #define AVUTIL_MEM_H #include #include #include "attributes.h" #include "error.h" #include "avutil.h" /** * @addtogroup lavu_mem * @{ */ #if defined(__INTEL_COMPILER) && __INTEL_COMPILER < 1110 || defined(__SUNPRO_C) #define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v #define DECLARE_ASM_CONST(n,t,v) const t __attribute__ ((aligned (n))) v #elif defined(__TI_COMPILER_VERSION__) #define DECLARE_ALIGNED(n,t,v) \ AV_PRAGMA(DATA_ALIGN(v,n)) \ t __attribute__((aligned(n))) v #define DECLARE_ASM_CONST(n,t,v) \ AV_PRAGMA(DATA_ALIGN(v,n)) \ static const t __attribute__((aligned(n))) v #elif defined(__GNUC__) #define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v #define DECLARE_ASM_CONST(n,t,v) static const t av_used __attribute__ ((aligned (n))) v #elif defined(_MSC_VER) #define DECLARE_ALIGNED(n,t,v) __declspec(align(n)) t v #define DECLARE_ASM_CONST(n,t,v) __declspec(align(n)) static const t v #else #define DECLARE_ALIGNED(n,t,v) t v #define DECLARE_ASM_CONST(n,t,v) static const t v #endif #if AV_GCC_VERSION_AT_LEAST(3,1) #define av_malloc_attrib __attribute__((__malloc__)) #else #define av_malloc_attrib #endif #if AV_GCC_VERSION_AT_LEAST(4,3) #define av_alloc_size(...) __attribute__((alloc_size(__VA_ARGS__))) #else #define av_alloc_size(...) #endif /** * Allocate a block of size bytes with alignment suitable for all * memory accesses (including vectors if available on the CPU). * @param size Size in bytes for the memory block to be allocated. * @return Pointer to the allocated block, NULL if the block cannot * be allocated. * @see av_mallocz() */ void *av_malloc(size_t size) av_malloc_attrib av_alloc_size(1); /** * Helper function to allocate a block of size * nmemb bytes with * using av_malloc() * @param nmemb Number of elements * @param size Size of the single element * @return Pointer to the allocated block, NULL if the block cannot * be allocated. * @see av_malloc() */ av_alloc_size(1, 2) static inline void *av_malloc_array(size_t nmemb, size_t size) { if (size <= 0 || nmemb >= INT_MAX / size) return NULL; return av_malloc(nmemb * size); } /** * Allocate or reallocate a block of memory. * If ptr is NULL and size > 0, allocate a new block. If * size is zero, free the memory block pointed to by ptr. * @param ptr Pointer to a memory block already allocated with * av_malloc(z)() or av_realloc() or NULL. * @param size Size in bytes for the memory block to be allocated or * reallocated. * @return Pointer to a newly reallocated block or NULL if the block * cannot be reallocated or the function is used to free the memory block. * @see av_fast_realloc() */ void *av_realloc(void *ptr, size_t size) av_alloc_size(2); /** * Allocate or reallocate a block of memory. * This function does the same thing as av_realloc, except: * - It takes two arguments and checks the result of the multiplication for * integer overflow. * - It frees the input block in case of failure, thus avoiding the memory * leak with the classic "buf = realloc(buf); if (!buf) return -1;". */ void *av_realloc_f(void *ptr, size_t nelem, size_t elsize); /** * Free a memory block which has been allocated with av_malloc(z)() or * av_realloc(). * @param ptr Pointer to the memory block which should be freed. * @note ptr = NULL is explicitly allowed. * @note It is recommended that you use av_freep() instead. * @see av_freep() */ void av_free(void *ptr); /** * Allocate a block of size bytes with alignment suitable for all * memory accesses (including vectors if available on the CPU) and * zero all the bytes of the block. * @param size Size in bytes for the memory block to be allocated. * @return Pointer to the allocated block, NULL if it cannot be allocated. * @see av_malloc() */ void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1); /** * Allocate a block of nmemb * size bytes with alignment suitable for all * memory accesses (including vectors if available on the CPU) and * zero all the bytes of the block. * The allocation will fail if nmemb * size is greater than or equal * to INT_MAX. * @param nmemb * @param size * @return Pointer to the allocated block, NULL if it cannot be allocated. */ void *av_calloc(size_t nmemb, size_t size) av_malloc_attrib; /** * Helper function to allocate a block of size * nmemb bytes with * using av_mallocz() * @param nmemb Number of elements * @param size Size of the single element * @return Pointer to the allocated block, NULL if the block cannot * be allocated. * @see av_mallocz() * @see av_malloc_array() */ av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size) { if (size <= 0 || nmemb >= INT_MAX / size) return NULL; return av_mallocz(nmemb * size); } /** * Duplicate the string s. * @param s string to be duplicated * @return Pointer to a newly allocated string containing a * copy of s or NULL if the string cannot be allocated. */ char *av_strdup(const char *s) av_malloc_attrib; /** * Duplicate the buffer p. * @param p buffer to be duplicated * @return Pointer to a newly allocated buffer containing a * copy of p or NULL if the buffer cannot be allocated. */ void *av_memdup(const void *p, size_t size); /** * Free a memory block which has been allocated with av_malloc(z)() or * av_realloc() and set the pointer pointing to it to NULL. * @param ptr Pointer to the pointer to the memory block which should * be freed. * @see av_free() */ void av_freep(void *ptr); /** * Add an element to a dynamic array. * * The array to grow is supposed to be an array of pointers to * structures, and the element to add must be a pointer to an already * allocated structure. * * The array is reallocated when its size reaches powers of 2. * Therefore, the amortized cost of adding an element is constant. * * In case of success, the pointer to the array is updated in order to * point to the new grown array, and the number pointed to by nb_ptr * is incremented. * In case of failure, the array is freed, *tab_ptr is set to NULL and * *nb_ptr is set to 0. * * @param tab_ptr pointer to the array to grow * @param nb_ptr pointer to the number of elements in the array * @param elem element to add */ void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem); /** * Multiply two size_t values checking for overflow. * @return 0 if success, AVERROR(EINVAL) if overflow. */ static inline int av_size_mult(size_t a, size_t b, size_t *r) { size_t t = a * b; /* Hack inspired from glibc: only try the division if nelem and elsize * are both greater than sqrt(SIZE_MAX). */ if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b) return AVERROR(EINVAL); *r = t; return 0; } /** * Set the maximum size that may me allocated in one block. */ void av_max_alloc(size_t max); /** * @brief deliberately overlapping memcpy implementation * @param dst destination buffer * @param back how many bytes back we start (the initial size of the overlapping window), must be > 0 * @param cnt number of bytes to copy, must be >= 0 * * cnt > back is valid, this will copy the bytes we just copied, * thus creating a repeating pattern with a period length of back. */ void av_memcpy_backptr(uint8_t *dst, int back, int cnt); /** * @} */ #endif /* AVUTIL_MEM_H */