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ffmpeg/libavutil/mem.c
Anton Khirnov 8ddc32629a mem: add av_strndup() for duplicating substrings
2014-08-13 17:24:18 +00:00

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/*
* default memory allocator for libavutil
* Copyright (c) 2002 Fabrice Bellard
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; 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 <stdint.h>
#include <stdlib.h>
#include <string.h>
#if HAVE_MALLOC_H
#include <malloc.h>
#endif
#include "avutil.h"
#include "common.h"
#include "intreadwrite.h"
#include "mem.h"
#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 possibly ambiguous cases */
if (size > (INT_MAX - 32) || !size)
return NULL;
#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_ALIGNED_MALLOC
ptr = _aligned_malloc(size, 32);
#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 possibly 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;
#elif HAVE_ALIGNED_MALLOC
return _aligned_realloc(ptr, size, 32);
#else
return realloc(ptr, size);
#endif
}
int av_reallocp(void *ptr, size_t size)
{
void **ptrptr = ptr;
void *ret;
if (!size) {
av_freep(ptr);
return 0;
}
ret = av_realloc(*ptrptr, size);
if (!ret) {
av_freep(ptr);
return AVERROR(ENOMEM);
}
*ptrptr = ret;
return 0;
}
void *av_realloc_array(void *ptr, size_t nmemb, size_t size)
{
if (!size || nmemb >= INT_MAX / size)
return NULL;
return av_realloc(ptr, nmemb * size);
}
int av_reallocp_array(void *ptr, size_t nmemb, size_t size)
{
void **ptrptr = ptr;
void *ret;
if (!size || nmemb >= INT_MAX / size)
return AVERROR(ENOMEM);
if (!nmemb) {
av_freep(ptr);
return 0;
}
ret = av_realloc(*ptrptr, nmemb * size);
if (!ret) {
av_freep(ptr);
return AVERROR(ENOMEM);
}
*ptrptr = ret;
return 0;
}
void av_free(void *ptr)
{
#if CONFIG_MEMALIGN_HACK
if (ptr)
free((char *)ptr - ((char *)ptr)[-1]);
#elif HAVE_ALIGNED_MALLOC
_aligned_free(ptr);
#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_realloc(NULL, len);
if (ptr)
memcpy(ptr, s, len);
}
return ptr;
}
char *av_strndup(const char *s, size_t len)
{
char *ret = NULL, *end;
if (!s)
return NULL;
end = memchr(s, 0, len);
if (end)
len = end - s;
ret = av_realloc(NULL, len + 1);
if (!ret)
return NULL;
memcpy(ret, s, len);
ret[len] = 0;
return ret;
}
static void fill16(uint8_t *dst, int len)
{
uint32_t v = AV_RN16(dst - 2);
v |= v << 16;
while (len >= 4) {
AV_WN32(dst, v);
dst += 4;
len -= 4;
}
while (len--) {
*dst = dst[-2];
dst++;
}
}
static void fill24(uint8_t *dst, int len)
{
#if HAVE_BIGENDIAN
uint32_t v = AV_RB24(dst - 3);
uint32_t a = v << 8 | v >> 16;
uint32_t b = v << 16 | v >> 8;
uint32_t c = v << 24 | v;
#else
uint32_t v = AV_RL24(dst - 3);
uint32_t a = v | v << 24;
uint32_t b = v >> 8 | v << 16;
uint32_t c = v >> 16 | v << 8;
#endif
while (len >= 12) {
AV_WN32(dst, a);
AV_WN32(dst + 4, b);
AV_WN32(dst + 8, c);
dst += 12;
len -= 12;
}
if (len >= 4) {
AV_WN32(dst, a);
dst += 4;
len -= 4;
}
if (len >= 4) {
AV_WN32(dst, b);
dst += 4;
len -= 4;
}
while (len--) {
*dst = dst[-3];
dst++;
}
}
static void fill32(uint8_t *dst, int len)
{
uint32_t v = AV_RN32(dst - 4);
while (len >= 4) {
AV_WN32(dst, v);
dst += 4;
len -= 4;
}
while (len--) {
*dst = dst[-4];
dst++;
}
}
void av_memcpy_backptr(uint8_t *dst, int back, int cnt)
{
const uint8_t *src = &dst[-back];
if (!back)
return;
if (back == 1) {
memset(dst, *src, cnt);
} else if (back == 2) {
fill16(dst, cnt);
} else if (back == 3) {
fill24(dst, cnt);
} else if (back == 4) {
fill32(dst, cnt);
} else {
if (cnt >= 16) {
int blocklen = back;
while (cnt > blocklen) {
memcpy(dst, src, blocklen);
dst += blocklen;
cnt -= blocklen;
blocklen <<= 1;
}
memcpy(dst, src, cnt);
return;
}
if (cnt >= 8) {
AV_COPY32U(dst, src);
AV_COPY32U(dst + 4, src + 4);
src += 8;
dst += 8;
cnt -= 8;
}
if (cnt >= 4) {
AV_COPY32U(dst, src);
src += 4;
dst += 4;
cnt -= 4;
}
if (cnt >= 2) {
AV_COPY16U(dst, src);
src += 2;
dst += 2;
cnt -= 2;
}
if (cnt)
*dst = *src;
}
}
void *av_fast_realloc(void *ptr, unsigned int *size, size_t min_size)
{
if (min_size < *size)
return ptr;
min_size = FFMAX(17 * min_size / 16 + 32, min_size);
ptr = av_realloc(ptr, min_size);
/* we could set this to the unmodified min_size but this is safer
* if the user lost the ptr and uses NULL now
*/
if (!ptr)
min_size = 0;
*size = min_size;
return ptr;
}
void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size)
{
void **p = ptr;
if (min_size < *size)
return;
min_size = FFMAX(17 * min_size / 16 + 32, min_size);
av_free(*p);
*p = av_malloc(min_size);
if (!*p)
min_size = 0;
*size = min_size;
}
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