summaryrefslogtreecommitdiff
path: root/libavutil/mem.c
blob: 4253740a1088dcdb1b2f6a600a3eda246c7a4756 (plain)
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
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
/*
 * default memory allocator for libavutil
 * Copyright (c) 2002 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; 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
 */

#define _XOPEN_SOURCE 600

#include "config.h"

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

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

#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 */

#define ALIGN (HAVE_AVX ? 32 : 16)

/* NOTE: if you want to override these functions with your own
 * implementations (not recommended) you have to link libav* as
 * dynamic libraries and remove -Wl,-Bsymbolic from the linker flags.
 * Note that this will cost performance. */

static size_t max_alloc_size= INT_MAX;

void av_max_alloc(size_t max){
    max_alloc_size = max;
}

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

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

#if CONFIG_MEMALIGN_HACK
    ptr = malloc(size + ALIGN);
    if (!ptr)
        return ptr;
    diff              = ((-(long)ptr - 1)&(ALIGN - 1)) + 1;
    ptr               = (char *)ptr + diff;
    ((char *)ptr)[-1] = diff;
#elif HAVE_POSIX_MEMALIGN
    if (size) //OS X on SDK 10.6 has a broken posix_memalign implementation
    if (posix_memalign(&ptr, ALIGN, size))
        ptr = NULL;
#elif HAVE_ALIGNED_MALLOC
    ptr = _aligned_malloc(size, ALIGN);
#elif HAVE_MEMALIGN
    ptr = memalign(ALIGN, 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
    if(!ptr && !size) {
        size = 1;
        ptr= av_malloc(1);
    }
#if CONFIG_MEMORY_POISONING
    if (ptr)
        memset(ptr, 0x2a, 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 > (max_alloc_size - 32))
        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];
    ptr = realloc((char *)ptr - diff, size + diff);
    if (ptr)
        ptr = (char *)ptr + diff;
    return ptr;
#elif HAVE_ALIGNED_MALLOC
    return _aligned_realloc(ptr, size + !size, ALIGN);
#else
    return realloc(ptr, size + !size);
#endif
}

void *av_realloc_f(void *ptr, size_t nelem, size_t elsize)
{
    size_t size;
    void *r;

    if (av_size_mult(elsize, nelem, &size)) {
        av_free(ptr);
        return NULL;
    }
    r = av_realloc(ptr, size);
    if (!r && size)
        av_free(ptr);
    return r;
}

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;
}

void *av_calloc(size_t nmemb, size_t size)
{
    if (size <= 0 || nmemb >= INT_MAX / size)
        return NULL;
    return av_mallocz(nmemb * size);
}

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;
}

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

    nb = *nb_ptr;
    tab = *(intptr_t**)tab_ptr;
    if ((nb & (nb - 1)) == 0) {
        if (nb == 0)
            nb_alloc = 1;
        else
            nb_alloc = nb * 2;
        tab = av_realloc(tab, nb_alloc * sizeof(intptr_t));
        *(intptr_t**)tab_ptr = tab;
    }
    tab[nb++] = (intptr_t)elem;
    *nb_ptr = nb;
}

static void fill16(uint8_t *dst, int len)
{
    uint32_t v = AV_RN16(dst - 2);

    v |= v << 16;

    while (len >= 4) {
        AV_WN32(dst, v);
        dst += 4;
        len -= 4;
    }

    while (len--) {
        *dst = dst[-2];
        dst++;
    }
}

static void fill24(uint8_t *dst, int len)
{
#if HAVE_BIGENDIAN
    uint32_t v = AV_RB24(dst - 3);
    uint32_t a = v << 8  | v >> 16;
    uint32_t b = v << 16 | v >> 8;
    uint32_t c = v << 24 | v;
#else
    uint32_t v = AV_RL24(dst - 3);
    uint32_t a = v       | v << 24;
    uint32_t b = v >> 8  | v << 16;
    uint32_t c = v >> 16 | v << 8;
#endif

    while (len >= 12) {
        AV_WN32(dst,     a);
        AV_WN32(dst + 4, b);
        AV_WN32(dst + 8, c);
        dst += 12;
        len -= 12;
    }

    if (len >= 4) {
        AV_WN32(dst, a);
        dst += 4;
        len -= 4;
    }

    if (len >= 4) {
        AV_WN32(dst, b);
        dst += 4;
        len -= 4;
    }

    while (len--) {
        *dst = dst[-3];
        dst++;
    }
}

static void fill32(uint8_t *dst, int len)
{
    uint32_t v = AV_RN32(dst - 4);

    while (len >= 4) {
        AV_WN32(dst, v);
        dst += 4;
        len -= 4;
    }

    while (len--) {
        *dst = dst[-4];
        dst++;
    }
}

void av_memcpy_backptr(uint8_t *dst, int back, int cnt)
{
    const uint8_t *src = &dst[-back];
    if (back <= 1) {
        memset(dst, *src, cnt);
    } else if (back == 2) {
        fill16(dst, cnt);
    } else if (back == 3) {
        fill24(dst, cnt);
    } else if (back == 4) {
        fill32(dst, cnt);
    } else {
        if (cnt >= 16) {
            int blocklen = back;
            while (cnt > blocklen) {
                memcpy(dst, src, blocklen);
                dst       += blocklen;
                cnt       -= blocklen;
                blocklen <<= 1;
            }
            memcpy(dst, src, cnt);
            return;
        }
        if (cnt >= 8) {
            AV_COPY32U(dst,     src);
            AV_COPY32U(dst + 4, src + 4);
            src += 8;
            dst += 8;
            cnt -= 8;
        }
        if (cnt >= 4) {
            AV_COPY32U(dst, src);
            src += 4;
            dst += 4;
            cnt -= 4;
        }
        if (cnt >= 2) {
            AV_COPY16U(dst, src);
            src += 2;
            dst += 2;
            cnt -= 2;
        }
        if (cnt)
            *dst = *src;
    }
}