mirror of
https://git.videolan.org/git/ffmpeg.git
synced 2024-08-21 08:45:06 +02:00
244 lines
7.8 KiB
C
244 lines
7.8 KiB
C
/*
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* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* memory handling functions
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*/
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#ifndef AVUTIL_MEM_H
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#define AVUTIL_MEM_H
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#include <limits.h>
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#include <stdint.h>
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#include "attributes.h"
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#include "error.h"
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#include "avutil.h"
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/**
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* @addtogroup lavu_mem
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* @{
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*/
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#if defined(__INTEL_COMPILER) && __INTEL_COMPILER < 1110 || defined(__SUNPRO_C)
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#define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v
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#define DECLARE_ASM_CONST(n,t,v) const t __attribute__ ((aligned (n))) v
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#elif defined(__TI_COMPILER_VERSION__)
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#define DECLARE_ALIGNED(n,t,v) \
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AV_PRAGMA(DATA_ALIGN(v,n)) \
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t __attribute__((aligned(n))) v
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#define DECLARE_ASM_CONST(n,t,v) \
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AV_PRAGMA(DATA_ALIGN(v,n)) \
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static const t __attribute__((aligned(n))) v
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#elif defined(__GNUC__)
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#define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v
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#define DECLARE_ASM_CONST(n,t,v) static const t av_used __attribute__ ((aligned (n))) v
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#elif defined(_MSC_VER)
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#define DECLARE_ALIGNED(n,t,v) __declspec(align(n)) t v
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#define DECLARE_ASM_CONST(n,t,v) __declspec(align(n)) static const t v
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#else
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#define DECLARE_ALIGNED(n,t,v) t v
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#define DECLARE_ASM_CONST(n,t,v) static const t v
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#endif
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#if AV_GCC_VERSION_AT_LEAST(3,1)
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#define av_malloc_attrib __attribute__((__malloc__))
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#else
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#define av_malloc_attrib
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#endif
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#if AV_GCC_VERSION_AT_LEAST(4,3)
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#define av_alloc_size(...) __attribute__((alloc_size(__VA_ARGS__)))
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#else
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#define av_alloc_size(...)
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#endif
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/**
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* Allocate a block of size bytes with alignment suitable for all
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* memory accesses (including vectors if available on the CPU).
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* @param size Size in bytes for the memory block to be allocated.
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* @return Pointer to the allocated block, NULL if the block cannot
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* be allocated.
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* @see av_mallocz()
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*/
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void *av_malloc(size_t size) av_malloc_attrib av_alloc_size(1);
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/**
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* Helper function to allocate a block of size * nmemb bytes with
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* using av_malloc()
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* @param nmemb Number of elements
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* @param size Size of the single element
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* @return Pointer to the allocated block, NULL if the block cannot
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* be allocated.
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* @see av_malloc()
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*/
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av_alloc_size(1, 2) static inline void *av_malloc_array(size_t nmemb, size_t size)
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{
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if (size <= 0 || nmemb >= INT_MAX / size)
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return NULL;
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return av_malloc(nmemb * size);
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}
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/**
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* Allocate or reallocate a block of memory.
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* If ptr is NULL and size > 0, allocate a new block. If
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* size is zero, free the memory block pointed to by ptr.
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* @param ptr Pointer to a memory block already allocated with
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* av_malloc(z)() or av_realloc() or NULL.
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* @param size Size in bytes for the memory block to be allocated or
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* reallocated.
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* @return Pointer to a newly reallocated block or NULL if the block
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* cannot be reallocated or the function is used to free the memory block.
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* @see av_fast_realloc()
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*/
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void *av_realloc(void *ptr, size_t size) av_alloc_size(2);
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/**
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* Allocate or reallocate a block of memory.
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* This function does the same thing as av_realloc, except:
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* - It takes two arguments and checks the result of the multiplication for
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* integer overflow.
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* - It frees the input block in case of failure, thus avoiding the memory
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* leak with the classic "buf = realloc(buf); if (!buf) return -1;".
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*/
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void *av_realloc_f(void *ptr, size_t nelem, size_t elsize);
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/**
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* Free a memory block which has been allocated with av_malloc(z)() or
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* av_realloc().
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* @param ptr Pointer to the memory block which should be freed.
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* @note ptr = NULL is explicitly allowed.
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* @note It is recommended that you use av_freep() instead.
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* @see av_freep()
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*/
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void av_free(void *ptr);
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/**
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* Allocate a block of size bytes with alignment suitable for all
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* memory accesses (including vectors if available on the CPU) and
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* zero all the bytes of the block.
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* @param size Size in bytes for the memory block to be allocated.
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* @return Pointer to the allocated block, NULL if it cannot be allocated.
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* @see av_malloc()
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*/
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void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1);
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/**
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* Allocate a block of nmemb * size bytes with alignment suitable for all
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* memory accesses (including vectors if available on the CPU) and
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* zero all the bytes of the block.
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* The allocation will fail if nmemb * size is greater than or equal
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* to INT_MAX.
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* @param nmemb
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* @param size
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* @return Pointer to the allocated block, NULL if it cannot be allocated.
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*/
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void *av_calloc(size_t nmemb, size_t size) av_malloc_attrib;
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/**
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* Helper function to allocate a block of size * nmemb bytes with
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* using av_mallocz()
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* @param nmemb Number of elements
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* @param size Size of the single element
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* @return Pointer to the allocated block, NULL if the block cannot
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* be allocated.
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* @see av_mallocz()
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* @see av_malloc_array()
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*/
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av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size)
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{
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if (size <= 0 || nmemb >= INT_MAX / size)
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return NULL;
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return av_mallocz(nmemb * size);
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}
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/**
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* Duplicate the string s.
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* @param s string to be duplicated
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* @return Pointer to a newly allocated string containing a
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* copy of s or NULL if the string cannot be allocated.
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*/
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char *av_strdup(const char *s) av_malloc_attrib;
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/**
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* Duplicate the buffer p.
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* @param p buffer to be duplicated
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* @return Pointer to a newly allocated buffer containing a
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* copy of p or NULL if the buffer cannot be allocated.
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*/
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void *av_memdup(const void *p, size_t size);
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/**
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* Free a memory block which has been allocated with av_malloc(z)() or
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* av_realloc() and set the pointer pointing to it to NULL.
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* @param ptr Pointer to the pointer to the memory block which should
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* be freed.
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* @see av_free()
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*/
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void av_freep(void *ptr);
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/**
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* Add an element to a dynamic array.
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*
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* @param tab_ptr Pointer to the array.
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* @param nb_ptr Pointer to the number of elements in the array.
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* @param elem Element to be added.
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*/
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void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem);
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/**
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* Multiply two size_t values checking for overflow.
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* @return 0 if success, AVERROR(EINVAL) if overflow.
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*/
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static inline int av_size_mult(size_t a, size_t b, size_t *r)
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{
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size_t t = a * b;
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/* Hack inspired from glibc: only try the division if nelem and elsize
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* are both greater than sqrt(SIZE_MAX). */
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if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b)
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return AVERROR(EINVAL);
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*r = t;
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return 0;
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}
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/**
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* Set the maximum size that may me allocated in one block.
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*/
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void av_max_alloc(size_t max);
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/**
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* @brief deliberately overlapping memcpy implementation
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* @param dst destination buffer
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* @param back how many bytes back we start (the initial size of the overlapping window), must be > 0
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* @param cnt number of bytes to copy, must be >= 0
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*
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* cnt > back is valid, this will copy the bytes we just copied,
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* thus creating a repeating pattern with a period length of back.
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*/
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void av_memcpy_backptr(uint8_t *dst, int back, int cnt);
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/**
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* @}
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*/
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#endif /* AVUTIL_MEM_H */
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