0fe9f5422a56970a723ee1cc7977a567c56e88d1
[libav.git] / libavutil / mem.c
1 /*
2 * default memory allocator for libavutil
3 * Copyright (c) 2002 Fabrice Bellard
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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.
11 *
12 * Libav 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.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * default memory allocator for libavutil
25 */
26
27 #include "config.h"
28
29 #include <limits.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #if HAVE_MALLOC_H
33 #include <malloc.h>
34 #endif
35
36 #include "avutil.h"
37 #include "mem.h"
38
39 /* here we can use OS-dependent allocation functions */
40 #undef free
41 #undef malloc
42 #undef realloc
43
44 #ifdef MALLOC_PREFIX
45
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)
51
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);
56 void free(void *ptr);
57
58 #endif /* MALLOC_PREFIX */
59
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. */
63
64 void *av_malloc(size_t size)
65 {
66 void *ptr = NULL;
67 #if CONFIG_MEMALIGN_HACK
68 long diff;
69 #endif
70
71 assert(size);
72
73 /* let's disallow possible ambiguous cases */
74 if (size > (INT_MAX-32) || !size)
75 return NULL;
76
77 #if CONFIG_MEMALIGN_HACK
78 ptr = malloc(size+32);
79 if(!ptr)
80 return ptr;
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))
86 ptr = NULL;
87 #elif HAVE_ALIGNED_MALLOC
88 ptr = _aligned_malloc(size, 32);
89 #elif HAVE_MEMALIGN
90 ptr = memalign(32,size);
91 /* Why 64?
92 Indeed, we should align it:
93 on 4 for 386
94 on 16 for 486
95 on 32 for 586, PPro - K6-III
96 on 64 for K7 (maybe for P3 too).
97 Because L1 and L2 caches are aligned on those values.
98 But I don't want to code such logic here!
99 */
100 /* Why 32?
101 For AVX ASM. SSE / NEON needs only 16.
102 Why not larger? Because I did not see a difference in benchmarks ...
103 */
104 /* benchmarks with P3
105 memalign(64)+1 3071,3051,3032
106 memalign(64)+2 3051,3032,3041
107 memalign(64)+4 2911,2896,2915
108 memalign(64)+8 2545,2554,2550
109 memalign(64)+16 2543,2572,2563
110 memalign(64)+32 2546,2545,2571
111 memalign(64)+64 2570,2533,2558
112
113 BTW, malloc seems to do 8-byte alignment by default here.
114 */
115 #else
116 ptr = malloc(size);
117 #endif
118 return ptr;
119 }
120
121 void *av_realloc(void *ptr, size_t size)
122 {
123 #if CONFIG_MEMALIGN_HACK
124 int diff;
125 #endif
126
127 /* let's disallow possible ambiguous cases */
128 if(size > (INT_MAX-16) )
129 return NULL;
130
131 #if CONFIG_MEMALIGN_HACK
132 //FIXME this isn't aligned correctly, though it probably isn't needed
133 if(!ptr) return av_malloc(size);
134 diff= ((char*)ptr)[-1];
135 return (char*)realloc((char*)ptr - diff, size + diff) + diff;
136 #elif HAVE_ALIGNED_MALLOC
137 return _aligned_realloc(ptr, size, 32);
138 #else
139 return realloc(ptr, size);
140 #endif
141 }
142
143 void av_free(void *ptr)
144 {
145 #if CONFIG_MEMALIGN_HACK
146 if (ptr)
147 free((char*)ptr - ((char*)ptr)[-1]);
148 #elif HAVE_ALIGNED_MALLOC
149 _aligned_free(ptr);
150 #else
151 free(ptr);
152 #endif
153 }
154
155 void av_freep(void *arg)
156 {
157 void **ptr= (void**)arg;
158 av_free(*ptr);
159 *ptr = NULL;
160 }
161
162 void *av_mallocz(size_t size)
163 {
164 void *ptr = av_malloc(size);
165 if (ptr)
166 memset(ptr, 0, size);
167 return ptr;
168 }
169
170 char *av_strdup(const char *s)
171 {
172 char *ptr= NULL;
173 if(s){
174 int len = strlen(s) + 1;
175 ptr = av_malloc(len);
176 if (ptr)
177 memcpy(ptr, s, len);
178 }
179 return ptr;
180 }