| /* |
| * 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 libavutil/mem.c |
| * 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 "mem.h" |
| |
| /* here we can use OS-dependent allocation functions */ |
| #undef free |
| #undef malloc |
| #undef realloc |
| |
| /* 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(unsigned int size) |
| { |
| void *ptr = NULL; |
| #if CONFIG_MEMALIGN_HACK |
| long diff; |
| #endif |
| |
| /* let's disallow possible ambiguous cases */ |
| if(size > (INT_MAX-16) ) |
| return NULL; |
| |
| #if CONFIG_MEMALIGN_HACK |
| ptr = malloc(size+16); |
| if(!ptr) |
| return ptr; |
| diff= ((-(long)ptr - 1)&15) + 1; |
| ptr = (char*)ptr + diff; |
| ((char*)ptr)[-1]= diff; |
| #elif HAVE_POSIX_MEMALIGN |
| if (posix_memalign(&ptr,16,size)) |
| ptr = NULL; |
| #elif HAVE_MEMALIGN |
| ptr = memalign(16,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 16? |
| Because some CPUs need alignment, for example SSE2 on P4, & most RISC CPUs |
| it will just trigger an exception and the unaligned load will be done in the |
| exception handler or it will just segfault (SSE2 on P4). |
| 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, unsigned int 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) |
| { |
| /* XXX: this test should not be needed on most libcs */ |
| if (ptr) |
| #if CONFIG_MEMALIGN_HACK |
| 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(unsigned int 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; |
| } |
| |