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
27 #define _XOPEN_SOURCE 600
41 /* here we can use OS-dependent allocation functions */
48 #define malloc AV_JOIN(MALLOC_PREFIX, malloc)
49 #define memalign AV_JOIN(MALLOC_PREFIX, memalign)
50 #define posix_memalign AV_JOIN(MALLOC_PREFIX, posix_memalign)
51 #define realloc AV_JOIN(MALLOC_PREFIX, realloc)
52 #define free AV_JOIN(MALLOC_PREFIX, free)
54 void *malloc(size_t size);
55 void *memalign(size_t align, size_t size);
56 int posix_memalign(void **ptr, size_t align, size_t size);
57 void *realloc(void *ptr, size_t size);
60 #endif /* MALLOC_PREFIX */
62 #define ALIGN (HAVE_AVX ? 32 : 16)
64 /* NOTE: if you want to override these functions with your own
65 * implementations (not recommended) you have to link libav* as
66 * dynamic libraries and remove -Wl,-Bsymbolic from the linker flags.
67 * Note that this will cost performance. */
69 static size_t max_alloc_size= INT_MAX;
71 void av_max_alloc(size_t max){
75 void *av_malloc(size_t size)
78 #if CONFIG_MEMALIGN_HACK
82 /* let's disallow possible ambiguous cases */
83 if (size > (max_alloc_size-32))
86 #if CONFIG_MEMALIGN_HACK
87 ptr = malloc(size+ALIGN);
90 diff= ((-(long)ptr - 1)&(ALIGN-1)) + 1;
91 ptr = (char*)ptr + diff;
92 ((char*)ptr)[-1]= diff;
93 #elif HAVE_POSIX_MEMALIGN
94 if (size) //OS X on SDK 10.6 has a broken posix_memalign implementation
95 if (posix_memalign(&ptr,ALIGN,size))
98 ptr = memalign(ALIGN,size);
100 Indeed, we should align it:
103 on 32 for 586, PPro - K6-III
104 on 64 for K7 (maybe for P3 too).
105 Because L1 and L2 caches are aligned on those values.
106 But I don't want to code such logic here!
109 For AVX ASM. SSE / NEON needs only 16.
110 Why not larger? Because I did not see a difference in benchmarks ...
112 /* benchmarks with P3
113 memalign(64)+1 3071,3051,3032
114 memalign(64)+2 3051,3032,3041
115 memalign(64)+4 2911,2896,2915
116 memalign(64)+8 2545,2554,2550
117 memalign(64)+16 2543,2572,2563
118 memalign(64)+32 2546,2545,2571
119 memalign(64)+64 2570,2533,2558
121 BTW, malloc seems to do 8-byte alignment by default here.
131 void *av_realloc(void *ptr, size_t size)
133 #if CONFIG_MEMALIGN_HACK
137 /* let's disallow possible ambiguous cases */
138 if (size > (max_alloc_size-32))
141 #if CONFIG_MEMALIGN_HACK
142 //FIXME this isn't aligned correctly, though it probably isn't needed
143 if(!ptr) return av_malloc(size);
144 diff= ((char*)ptr)[-1];
145 ptr= realloc((char*)ptr - diff, size + diff);
146 if(ptr) ptr = (char*)ptr + diff;
149 return realloc(ptr, size + !size);
153 void *av_realloc_f(void *ptr, size_t nelem, size_t elsize)
158 if (av_size_mult(elsize, nelem, &size)) {
162 r = av_realloc(ptr, size);
168 void av_free(void *ptr)
170 #if CONFIG_MEMALIGN_HACK
172 free((char*)ptr - ((char*)ptr)[-1]);
178 void av_freep(void *arg)
180 void **ptr= (void**)arg;
185 void *av_mallocz(size_t size)
187 void *ptr = av_malloc(size);
189 memset(ptr, 0, size);
193 void *av_calloc(size_t nmemb, size_t size)
195 if (size <= 0 || nmemb >= INT_MAX / size)
197 return av_mallocz(nmemb * size);
200 char *av_strdup(const char *s)
204 int len = strlen(s) + 1;
205 ptr = av_malloc(len);
212 /* add one element to a dynamic array */
213 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem)
215 /* see similar ffmpeg.c:grow_array() */
220 tab = *(intptr_t**)tab_ptr;
221 if ((nb & (nb - 1)) == 0) {
226 tab = av_realloc(tab, nb_alloc * sizeof(intptr_t));
227 *(intptr_t**)tab_ptr = tab;
229 tab[nb++] = (intptr_t)elem;