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#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
52void *malloc(size_t size);
53void *memalign(size_t align, size_t size);
54int   posix_memalign(void **ptr, size_t align, size_t size);
55void *realloc(void *ptr, size_t size);
56void  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
64void *av_malloc(unsigned int size)
65{
66    void *ptr = NULL;
67#if CONFIG_MEMALIGN_HACK
68    long diff;
69#endif
70
71    /* let's disallow possible ambiguous cases */
72    if(size > (INT_MAX-16) )
73        return NULL;
74
75#if CONFIG_MEMALIGN_HACK
76    ptr = malloc(size+16);
77    if(!ptr)
78        return ptr;
79    diff= ((-(long)ptr - 1)&15) + 1;
80    ptr = (char*)ptr + diff;
81    ((char*)ptr)[-1]= diff;
82#elif HAVE_POSIX_MEMALIGN
83    if (posix_memalign(&ptr,16,size))
84        ptr = NULL;
85#elif HAVE_MEMALIGN
86    ptr = memalign(16,size);
87    /* Why 64?
88       Indeed, we should align it:
89         on 4 for 386
90         on 16 for 486
91         on 32 for 586, PPro - K6-III
92         on 64 for K7 (maybe for P3 too).
93       Because L1 and L2 caches are aligned on those values.
94       But I don't want to code such logic here!
95     */
96     /* Why 16?
97        Because some CPUs need alignment, for example SSE2 on P4, & most RISC CPUs
98        it will just trigger an exception and the unaligned load will be done in the
99        exception handler or it will just segfault (SSE2 on P4).
100        Why not larger? Because I did not see a difference in benchmarks ...
101     */
102     /* benchmarks with P3
103        memalign(64)+1          3071,3051,3032
104        memalign(64)+2          3051,3032,3041
105        memalign(64)+4          2911,2896,2915
106        memalign(64)+8          2545,2554,2550
107        memalign(64)+16         2543,2572,2563
108        memalign(64)+32         2546,2545,2571
109        memalign(64)+64         2570,2533,2558
110
111        BTW, malloc seems to do 8-byte alignment by default here.
112     */
113#else
114    ptr = malloc(size);
115#endif
116    return ptr;
117}
118
119void *av_realloc(void *ptr, unsigned int size)
120{
121#if CONFIG_MEMALIGN_HACK
122    int diff;
123#endif
124
125    /* let's disallow possible ambiguous cases */
126    if(size > (INT_MAX-16) )
127        return NULL;
128
129#if CONFIG_MEMALIGN_HACK
130    //FIXME this isn't aligned correctly, though it probably isn't needed
131    if(!ptr) return av_malloc(size);
132    diff= ((char*)ptr)[-1];
133    return (char*)realloc((char*)ptr - diff, size + diff) + diff;
134#else
135    return realloc(ptr, size);
136#endif
137}
138
139void av_free(void *ptr)
140{
141    /* XXX: this test should not be needed on most libcs */
142    if (ptr)
143#if CONFIG_MEMALIGN_HACK
144        free((char*)ptr - ((char*)ptr)[-1]);
145#else
146        free(ptr);
147#endif
148}
149
150void av_freep(void *arg)
151{
152    void **ptr= (void**)arg;
153    av_free(*ptr);
154    *ptr = NULL;
155}
156
157void *av_mallocz(unsigned int size)
158{
159    void *ptr = av_malloc(size);
160    if (ptr)
161        memset(ptr, 0, size);
162    return ptr;
163}
164
165char *av_strdup(const char *s)
166{
167    char *ptr= NULL;
168    if(s){
169        int len = strlen(s) + 1;
170        ptr = av_malloc(len);
171        if (ptr)
172            memcpy(ptr, s, len);
173    }
174    return ptr;
175}
176
177