2 * default memory allocator for libavutil
3 * Copyright (c) 2002 Fabrice Bellard
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * default memory allocator for libavutil
39 /* here we can use OS-dependent allocation functions */
46 #define malloc AV_JOIN(MALLOC_PREFIX, malloc)
47 #define memalign AV_JOIN(MALLOC_PREFIX, memalign)
48 #define posix_memalign AV_JOIN(MALLOC_PREFIX, posix_memalign)
49 #define realloc AV_JOIN(MALLOC_PREFIX, realloc)
50 #define free AV_JOIN(MALLOC_PREFIX, free)
52 void *malloc(size_t size);
53 void *memalign(size_t align, size_t size);
54 int posix_memalign(void **ptr, size_t align, size_t size);
55 void *realloc(void *ptr, size_t size);
58 #endif /* MALLOC_PREFIX */
60 /* You can redefine av_malloc and av_free in your project to use your
61 memory allocator. You do not need to suppress this file because the
62 linker will do it automatically. */
64 void *av_malloc(size_t size)
67 #if CONFIG_MEMALIGN_HACK
71 /* let's disallow possible ambiguous cases */
72 if(size > (INT_MAX-32) )
77 #if CONFIG_MEMALIGN_HACK
78 ptr = malloc(size+32);
81 diff= ((-(long)ptr - 1)&31) + 1;
82 ptr = (char*)ptr + diff;
83 ((char*)ptr)[-1]= diff;
84 #elif HAVE_POSIX_MEMALIGN
85 if (posix_memalign(&ptr,32,size))
88 ptr = memalign(32,size);
90 Indeed, we should align it:
93 on 32 for 586, PPro - K6-III
94 on 64 for K7 (maybe for P3 too).
95 Because L1 and L2 caches are aligned on those values.
96 But I don't want to code such logic here!
99 For AVX ASM. SSE / NEON needs only 16.
100 Why not larger? Because I did not see a difference in benchmarks ...
102 /* benchmarks with P3
103 memalign(64)+1 3071,3051,3032
104 memalign(64)+2 3051,3032,3041
105 memalign(64)+4 2911,2896,2915
106 memalign(64)+8 2545,2554,2550
107 memalign(64)+16 2543,2572,2563
108 memalign(64)+32 2546,2545,2571
109 memalign(64)+64 2570,2533,2558
111 BTW, malloc seems to do 8-byte alignment by default here.
119 void *av_realloc(void *ptr, size_t size)
121 #if CONFIG_MEMALIGN_HACK
125 /* let's disallow possible ambiguous cases */
126 if(size > (INT_MAX-16) )
129 #if CONFIG_MEMALIGN_HACK
130 //FIXME this isn't aligned correctly, though it probably isn't needed
131 if(!ptr) return av_malloc(size);
132 diff= ((char*)ptr)[-1];
133 return (char*)realloc((char*)ptr - diff, size + diff) + diff;
135 return realloc(ptr, size);
139 void av_free(void *ptr)
141 #if CONFIG_MEMALIGN_HACK
143 free((char*)ptr - ((char*)ptr)[-1]);
149 void av_freep(void *arg)
151 void **ptr= (void**)arg;
156 void *av_mallocz(size_t size)
158 void *ptr = av_malloc(size);
160 memset(ptr, 0, size);
164 char *av_strdup(const char *s)
168 int len = strlen(s) + 1;
169 ptr = av_malloc(len);
176 /* add one element to a dynamic array */
177 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem)
179 /* see similar ffmpeg.c:grow_array() */
184 tab = *(intptr_t**)tab_ptr;
185 if ((nb & (nb - 1)) == 0) {
190 tab = av_realloc(tab, nb_alloc * sizeof(intptr_t));
191 *(intptr_t**)tab_ptr = tab;
193 tab[nb++] = (intptr_t)elem;