aboutsummaryrefslogtreecommitdiffstats
path: root/libavutil/mem.c
blob: 3769da7d21adc2b4f91bb0898a9c4d55aec9d621 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
/*
 * default memory allocator for libavutil
 * Copyright (c) 2002 Fabrice Bellard
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * default memory allocator for libavutil
 */

#include "config.h"

#include <limits.h>
#include <stdlib.h>
#include <string.h>
#if HAVE_MALLOC_H
#include <malloc.h>
#endif

#include "avutil.h"
#include "mem.h"

/* here we can use OS-dependent allocation functions */
#undef free
#undef malloc
#undef realloc

#ifdef MALLOC_PREFIX

#define malloc         AV_JOIN(MALLOC_PREFIX, malloc)
#define memalign       AV_JOIN(MALLOC_PREFIX, memalign)
#define posix_memalign AV_JOIN(MALLOC_PREFIX, posix_memalign)
#define realloc        AV_JOIN(MALLOC_PREFIX, realloc)
#define free           AV_JOIN(MALLOC_PREFIX, free)

void *malloc(size_t size);
void *memalign(size_t align, size_t size);
int   posix_memalign(void **ptr, size_t align, size_t size);
void *realloc(void *ptr, size_t size);
void  free(void *ptr);

#endif /* MALLOC_PREFIX */

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

void *av_malloc(size_t size)
{
    void *ptr = NULL;
#if CONFIG_MEMALIGN_HACK
    long diff;
#endif

    /* let's disallow possible ambiguous cases */
    if (size > (INT_MAX-32) || !size)
        return NULL;

#if CONFIG_MEMALIGN_HACK
    ptr = malloc(size+32);
    if(!ptr)
        return ptr;
    diff= ((-(long)ptr - 1)&31) + 1;
    ptr = (char*)ptr + diff;
    ((char*)ptr)[-1]= diff;
#elif HAVE_POSIX_MEMALIGN
    if (posix_memalign(&ptr,32,size))
        ptr = NULL;
#elif HAVE_ALIGNED_MALLOC
    ptr = _aligned_malloc(size, 32);
#elif HAVE_MEMALIGN
    ptr = memalign(32,size);
    /* Why 64?
       Indeed, we should align it:
         on 4 for 386
         on 16 for 486
         on 32 for 586, PPro - K6-III
         on 64 for K7 (maybe for P3 too).
       Because L1 and L2 caches are aligned on those values.
       But I don't want to code such logic here!
     */
     /* Why 32?
        For AVX ASM. SSE / NEON needs only 16.
        Why not larger? Because I did not see a difference in benchmarks ...
     */
     /* benchmarks with P3
        memalign(64)+1          3071,3051,3032
        memalign(64)+2          3051,3032,3041
        memalign(64)+4          2911,2896,2915
        memalign(64)+8          2545,2554,2550
        memalign(64)+16         2543,2572,2563
        memalign(64)+32         2546,2545,2571
        memalign(64)+64         2570,2533,2558

        BTW, malloc seems to do 8-byte alignment by default here.
     */
#else
    ptr = malloc(size);
#endif
    return ptr;
}

void *av_realloc(void *ptr, size_t size)
{
#if CONFIG_MEMALIGN_HACK
    int diff;
#endif

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

#if CONFIG_MEMALIGN_HACK
    //FIXME this isn't aligned correctly, though it probably isn't needed
    if(!ptr) return av_malloc(size);
    diff= ((char*)ptr)[-1];
    return (char*)realloc((char*)ptr - diff, size + diff) + diff;
#elif HAVE_ALIGNED_MALLOC
    return _aligned_realloc(ptr, size, 32);
#else
    return realloc(ptr, size);
#endif
}

void av_free(void *ptr)
{
#if CONFIG_MEMALIGN_HACK
    if (ptr)
        free((char*)ptr - ((char*)ptr)[-1]);
#elif HAVE_ALIGNED_MALLOC
    _aligned_free(ptr);
#else
    free(ptr);
#endif
}

void av_freep(void *arg)
{
    void **ptr= (void**)arg;
    av_free(*ptr);
    *ptr = NULL;
}

void *av_mallocz(size_t size)
{
    void *ptr = av_malloc(size);
    if (ptr)
        memset(ptr, 0, size);
    return ptr;
}

char *av_strdup(const char *s)
{
    char *ptr= NULL;
    if(s){
        int len = strlen(s) + 1;
        ptr = av_malloc(len);
        if (ptr)
            memcpy(ptr, s, len);
    }
    return ptr;
}