Statistics
| Branch: | Revision:

ffmpeg / libavutil / mem.c @ 518cdff8

History | View | Annotate | Download (4.89 KB)

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
24
 * default memory allocator for libavutil
25
 */
26

    
27
#define _XOPEN_SOURCE 600
28

    
29
#include "config.h"
30

    
31
#include <limits.h>
32
#include <stdlib.h>
33
#include <string.h>
34
#if HAVE_MALLOC_H
35
#include <malloc.h>
36
#endif
37

    
38
#include "avutil.h"
39
#include "mem.h"
40

    
41
/* here we can use OS-dependent allocation functions */
42
#undef free
43
#undef malloc
44
#undef realloc
45

    
46
#ifdef MALLOC_PREFIX
47

    
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)
53

    
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);
58
void  free(void *ptr);
59

    
60
#endif /* MALLOC_PREFIX */
61

    
62
#define ALIGN (HAVE_AVX ? 32 : 16)
63

    
64
/* You can redefine av_malloc and av_free in your project to use your
65
   memory allocator. You do not need to suppress this file because the
66
   linker will do it automatically. */
67

    
68
void *av_malloc(size_t size)
69
{
70
    void *ptr = NULL;
71
#if CONFIG_MEMALIGN_HACK
72
    long diff;
73
#endif
74

    
75
    /* let's disallow possible ambiguous cases */
76
    if(size > (INT_MAX-32) )
77
        return NULL;
78

    
79
#if CONFIG_MEMALIGN_HACK
80
    ptr = malloc(size+ALIGN);
81
    if(!ptr)
82
        return ptr;
83
    diff= ((-(long)ptr - 1)&(ALIGN-1)) + 1;
84
    ptr = (char*)ptr + diff;
85
    ((char*)ptr)[-1]= diff;
86
#elif HAVE_POSIX_MEMALIGN
87
    if (posix_memalign(&ptr,ALIGN,size))
88
        ptr = NULL;
89
#elif HAVE_MEMALIGN
90
    ptr = memalign(ALIGN,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
    if(!ptr && !size)
119
        ptr= av_malloc(1);
120
    return ptr;
121
}
122

    
123
void *av_realloc(void *ptr, size_t size)
124
{
125
#if CONFIG_MEMALIGN_HACK
126
    int diff;
127
#endif
128

    
129
    /* let's disallow possible ambiguous cases */
130
    if(size > (INT_MAX-16) )
131
        return NULL;
132

    
133
#if CONFIG_MEMALIGN_HACK
134
    //FIXME this isn't aligned correctly, though it probably isn't needed
135
    if(!ptr) return av_malloc(size);
136
    diff= ((char*)ptr)[-1];
137
    return (char*)realloc((char*)ptr - diff, size + diff) + diff;
138
#else
139
    return realloc(ptr, size + !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
#else
149
    free(ptr);
150
#endif
151
}
152

    
153
void av_freep(void *arg)
154
{
155
    void **ptr= (void**)arg;
156
    av_free(*ptr);
157
    *ptr = NULL;
158
}
159

    
160
void *av_mallocz(size_t size)
161
{
162
    void *ptr = av_malloc(size);
163
    if (ptr)
164
        memset(ptr, 0, size);
165
    return ptr;
166
}
167

    
168
char *av_strdup(const char *s)
169
{
170
    char *ptr= NULL;
171
    if(s){
172
        int len = strlen(s) + 1;
173
        ptr = av_malloc(len);
174
        if (ptr)
175
            memcpy(ptr, s, len);
176
    }
177
    return ptr;
178
}
179

    
180
/* add one element to a dynamic array */
181
void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem)
182
{
183
    /* see similar ffmpeg.c:grow_array() */
184
    int nb, nb_alloc;
185
    intptr_t *tab;
186

    
187
    nb = *nb_ptr;
188
    tab = *(intptr_t**)tab_ptr;
189
    if ((nb & (nb - 1)) == 0) {
190
        if (nb == 0)
191
            nb_alloc = 1;
192
        else
193
            nb_alloc = nb * 2;
194
        tab = av_realloc(tab, nb_alloc * sizeof(intptr_t));
195
        *(intptr_t**)tab_ptr = tab;
196
    }
197
    tab[nb++] = (intptr_t)elem;
198
    *nb_ptr = nb;
199
}