/* * 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 <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(FF_INTERNAL_MEM_TYPE 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, FF_INTERNAL_MEM_TYPE 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(FF_INTERNAL_MEM_TYPE 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; }