Directly #include a bunch of indirectly #included headers.
[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 FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22 /**
23 * @file mem.c
24 * default memory allocator for libavutil.
25 */
26
27 #include "config.h"
28 #include "common.h"
29
30 /* here we can use OS dependent allocation functions */
31 #undef malloc
32 #undef free
33 #undef realloc
34
35 #include <limits.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #if HAVE_MALLOC_H
39 #include <malloc.h>
40 #endif
41
42 /* you can redefine av_malloc and av_free in your project to use your
43 memory allocator. You do not need to suppress this file because the
44 linker will do it automatically */
45
46 void *av_malloc(unsigned int size)
47 {
48 void *ptr = NULL;
49 #if CONFIG_MEMALIGN_HACK
50 long diff;
51 #endif
52
53 /* let's disallow possible ambiguous cases */
54 if(size > (INT_MAX-16) )
55 return NULL;
56
57 #if CONFIG_MEMALIGN_HACK
58 ptr = malloc(size+16);
59 if(!ptr)
60 return ptr;
61 diff= ((-(long)ptr - 1)&15) + 1;
62 ptr = (char*)ptr + diff;
63 ((char*)ptr)[-1]= diff;
64 #elif HAVE_POSIX_MEMALIGN
65 posix_memalign(&ptr,16,size);
66 #elif HAVE_MEMALIGN
67 ptr = memalign(16,size);
68 /* Why 64?
69 Indeed, we should align it:
70 on 4 for 386
71 on 16 for 486
72 on 32 for 586, PPro - k6-III
73 on 64 for K7 (maybe for P3 too).
74 Because L1 and L2 caches are aligned on those values.
75 But I don't want to code such logic here!
76 */
77 /* Why 16?
78 Because some CPUs need alignment, for example SSE2 on P4, & most RISC CPUs
79 it will just trigger an exception and the unaligned load will be done in the
80 exception handler or it will just segfault (SSE2 on P4)
81 Why not larger? Because I did not see a difference in benchmarks ...
82 */
83 /* benchmarks with p3
84 memalign(64)+1 3071,3051,3032
85 memalign(64)+2 3051,3032,3041
86 memalign(64)+4 2911,2896,2915
87 memalign(64)+8 2545,2554,2550
88 memalign(64)+16 2543,2572,2563
89 memalign(64)+32 2546,2545,2571
90 memalign(64)+64 2570,2533,2558
91
92 btw, malloc seems to do 8 byte alignment by default here
93 */
94 #else
95 ptr = malloc(size);
96 #endif
97 return ptr;
98 }
99
100 void *av_realloc(void *ptr, unsigned int size)
101 {
102 #if CONFIG_MEMALIGN_HACK
103 int diff;
104 #endif
105
106 /* let's disallow possible ambiguous cases */
107 if(size > (INT_MAX-16) )
108 return NULL;
109
110 #if CONFIG_MEMALIGN_HACK
111 //FIXME this isn't aligned correctly, though it probably isn't needed
112 if(!ptr) return av_malloc(size);
113 diff= ((char*)ptr)[-1];
114 return (char*)realloc((char*)ptr - diff, size + diff) + diff;
115 #else
116 return realloc(ptr, size);
117 #endif
118 }
119
120 void av_free(void *ptr)
121 {
122 /* XXX: this test should not be needed on most libcs */
123 if (ptr)
124 #if CONFIG_MEMALIGN_HACK
125 free((char*)ptr - ((char*)ptr)[-1]);
126 #else
127 free(ptr);
128 #endif
129 }
130
131 void av_freep(void *arg)
132 {
133 void **ptr= (void**)arg;
134 av_free(*ptr);
135 *ptr = NULL;
136 }
137
138 void *av_mallocz(unsigned int size)
139 {
140 void *ptr = av_malloc(size);
141 if (ptr)
142 memset(ptr, 0, size);
143 return ptr;
144 }
145
146 char *av_strdup(const char *s)
147 {
148 char *ptr= NULL;
149 if(s){
150 int len = strlen(s) + 1;
151 ptr = av_malloc(len);
152 if (ptr)
153 memcpy(ptr, s, len);
154 }
155 return ptr;
156 }
157