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