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/*
* default memory allocator for libavutil
* Copyright (c) 2002 Fabrice Bellard
*
* 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
* default memory allocator for libavutil
*/
#include "config.h"
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#if HAVE_MALLOC_H
#include <malloc.h>
#endif
#include "avutil.h"
#include "mem.h"
/* here we can use OS-dependent allocation functions */
#undef free
#undef malloc
#undef realloc
#ifdef MALLOC_PREFIX
#define malloc AV_JOIN(MALLOC_PREFIX, malloc)
#define memalign AV_JOIN(MALLOC_PREFIX, memalign)
#define posix_memalign AV_JOIN(MALLOC_PREFIX, posix_memalign)
#define realloc AV_JOIN(MALLOC_PREFIX, realloc)
#define free AV_JOIN(MALLOC_PREFIX, free)
void *malloc(size_t size);
void *memalign(size_t align, size_t size);
int posix_memalign(void **ptr, size_t align, size_t size);
void *realloc(void *ptr, size_t size);
void free(void *ptr);
#endif /* MALLOC_PREFIX */
/* You can redefine av_malloc and av_free in your project to use your
memory allocator. You do not need to suppress this file because the
linker will do it automatically. */
void *av_malloc(size_t size)
{
void *ptr = NULL;
#if CONFIG_MEMALIGN_HACK
long diff;
#endif
/* let's disallow possible ambiguous cases */
if(size > (INT_MAX-32) )
return NULL;
else if(!size)
size= 1;
#if CONFIG_MEMALIGN_HACK
ptr = malloc(size+32);
if(!ptr)
return ptr;
diff= ((-(long)ptr - 1)&31) + 1;
ptr = (char*)ptr + diff;
((char*)ptr)[-1]= diff;
#elif HAVE_POSIX_MEMALIGN
if (posix_memalign(&ptr,32,size))
ptr = NULL;
#elif HAVE_MEMALIGN
ptr = memalign(32,size);
/* Why 64?
Indeed, we should align it:
on 4 for 386
on 16 for 486
on 32 for 586, PPro - K6-III
on 64 for K7 (maybe for P3 too).
Because L1 and L2 caches are aligned on those values.
But I don't want to code such logic here!
*/
/* Why 32?
For AVX ASM. SSE / NEON needs only 16.
Why not larger? Because I did not see a difference in benchmarks ...
*/
/* benchmarks with P3
memalign(64)+1 3071,3051,3032
memalign(64)+2 3051,3032,3041
memalign(64)+4 2911,2896,2915
memalign(64)+8 2545,2554,2550
memalign(64)+16 2543,2572,2563
memalign(64)+32 2546,2545,2571
memalign(64)+64 2570,2533,2558
BTW, malloc seems to do 8-byte alignment by default here.
*/
#else
ptr = malloc(size);
#endif
return ptr;
}
void *av_realloc(void *ptr, size_t size)
{
#if CONFIG_MEMALIGN_HACK
int diff;
#endif
/* let's disallow possible ambiguous cases */
if(size > (INT_MAX-16) )
return NULL;
#if CONFIG_MEMALIGN_HACK
//FIXME this isn't aligned correctly, though it probably isn't needed
if(!ptr) return av_malloc(size);
diff= ((char*)ptr)[-1];
return (char*)realloc((char*)ptr - diff, size + diff) + diff;
#else
return realloc(ptr, size);
#endif
}
void av_free(void *ptr)
{
#if CONFIG_MEMALIGN_HACK
if (ptr)
free((char*)ptr - ((char*)ptr)[-1]);
#else
free(ptr);
#endif
}
void av_freep(void *arg)
{
void **ptr= (void**)arg;
av_free(*ptr);
*ptr = NULL;
}
void *av_mallocz(size_t size)
{
void *ptr = av_malloc(size);
if (ptr)
memset(ptr, 0, size);
return ptr;
}
char *av_strdup(const char *s)
{
char *ptr= NULL;
if(s){
int len = strlen(s) + 1;
ptr = av_malloc(len);
if (ptr)
memcpy(ptr, s, len);
}
return ptr;
}
/* add one element to a dynamic array */
void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem)
{
/* see similar ffmpeg.c:grow_array() */
int nb, nb_alloc;
intptr_t *tab;
nb = *nb_ptr;
tab = *(intptr_t**)tab_ptr;
if ((nb & (nb - 1)) == 0) {
if (nb == 0)
nb_alloc = 1;
else
nb_alloc = nb * 2;
tab = av_realloc(tab, nb_alloc * sizeof(intptr_t));
*(intptr_t**)tab_ptr = tab;
}
tab[nb++] = (intptr_t)elem;
*nb_ptr = nb;
}
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