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
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(size_t 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-32) )
73        return NULL;
74
75#if CONFIG_MEMALIGN_HACK
76    ptr = malloc(size+32);
77    if(!ptr)
78        return ptr;
79    diff= ((-(long)ptr - 1)&31) + 1;
80    ptr = (char*)ptr + diff;
81    ((char*)ptr)[-1]= diff;
82#elif HAVE_POSIX_MEMALIGN
83    if (posix_memalign(&ptr,32,size))
84        ptr = NULL;
85#elif HAVE_MEMALIGN
86    ptr = memalign(32,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 32?
97        For AVX ASM. SSE / NEON needs only 16.
98        Why not larger? Because I did not see a difference in benchmarks ...
99     */
100     /* benchmarks with P3
101        memalign(64)+1          3071,3051,3032
102        memalign(64)+2          3051,3032,3041
103        memalign(64)+4          2911,2896,2915
104        memalign(64)+8          2545,2554,2550
105        memalign(64)+16         2543,2572,2563
106        memalign(64)+32         2546,2545,2571
107        memalign(64)+64         2570,2533,2558
108
109        BTW, malloc seems to do 8-byte alignment by default here.
110     */
111#else
112    ptr = malloc(size);
113#endif
114    return ptr;
115}
116
117void *av_realloc(void *ptr, size_t size)
118{
119#if CONFIG_MEMALIGN_HACK
120    int diff;
121#endif
122
123    /* let's disallow possible ambiguous cases */
124    if(size > (INT_MAX-16) )
125        return NULL;
126
127#if CONFIG_MEMALIGN_HACK
128    //FIXME this isn't aligned correctly, though it probably isn't needed
129    if(!ptr) return av_malloc(size);
130    diff= ((char*)ptr)[-1];
131    return (char*)realloc((char*)ptr - diff, size + diff) + diff;
132#else
133    return realloc(ptr, size);
134#endif
135}
136
137void av_free(void *ptr)
138{
139#if CONFIG_MEMALIGN_HACK
140    if (ptr)
141        free((char*)ptr - ((char*)ptr)[-1]);
142#else
143    free(ptr);
144#endif
145}
146
147void av_freep(void *arg)
148{
149    void **ptr= (void**)arg;
150    av_free(*ptr);
151    *ptr = NULL;
152}
153
154void *av_mallocz(size_t size)
155{
156    void *ptr = av_malloc(size);
157    if (ptr)
158        memset(ptr, 0, size);
159    return ptr;
160}
161
162char *av_strdup(const char *s)
163{
164    char *ptr= NULL;
165    if(s){
166        int len = strlen(s) + 1;
167        ptr = av_malloc(len);
168        if (ptr)
169            memcpy(ptr, s, len);
170    }
171    return ptr;
172}
173
174