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mem.c
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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 <stdint.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #if HAVE_MALLOC_H
36 #include <malloc.h>
37 #endif
38 
39 #include "avassert.h"
40 #include "avutil.h"
41 #include "common.h"
42 #include "dynarray.h"
43 #include "intreadwrite.h"
44 #include "mem.h"
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 #include "mem_internal.h"
63 
64 #define ALIGN (HAVE_AVX ? 32 : 16)
65 
66 /* NOTE: if you want to override these functions with your own
67  * implementations (not recommended) you have to link libav* as
68  * dynamic libraries and remove -Wl,-Bsymbolic from the linker flags.
69  * Note that this will cost performance. */
70 
71 static size_t max_alloc_size= INT_MAX;
72 
73 void av_max_alloc(size_t max){
74  max_alloc_size = max;
75 }
76 
77 void *av_malloc(size_t size)
78 {
79  void *ptr = NULL;
80 #if CONFIG_MEMALIGN_HACK
81  long diff;
82 #endif
83 
84  /* let's disallow possibly ambiguous cases */
85  if (size > (max_alloc_size - 32))
86  return NULL;
87 
88 #if CONFIG_MEMALIGN_HACK
89  ptr = malloc(size + ALIGN);
90  if (!ptr)
91  return ptr;
92  diff = ((~(long)ptr)&(ALIGN - 1)) + 1;
93  ptr = (char *)ptr + diff;
94  ((char *)ptr)[-1] = diff;
95 #elif HAVE_POSIX_MEMALIGN
96  if (size) //OS X on SDK 10.6 has a broken posix_memalign implementation
97  if (posix_memalign(&ptr, ALIGN, size))
98  ptr = NULL;
99 #elif HAVE_ALIGNED_MALLOC
100  ptr = _aligned_malloc(size, ALIGN);
101 #elif HAVE_MEMALIGN
102 #ifndef __DJGPP__
103  ptr = memalign(ALIGN, size);
104 #else
105  ptr = memalign(size, ALIGN);
106 #endif
107  /* Why 64?
108  * Indeed, we should align it:
109  * on 4 for 386
110  * on 16 for 486
111  * on 32 for 586, PPro - K6-III
112  * on 64 for K7 (maybe for P3 too).
113  * Because L1 and L2 caches are aligned on those values.
114  * But I don't want to code such logic here!
115  */
116  /* Why 32?
117  * For AVX ASM. SSE / NEON needs only 16.
118  * Why not larger? Because I did not see a difference in benchmarks ...
119  */
120  /* benchmarks with P3
121  * memalign(64) + 1 3071, 3051, 3032
122  * memalign(64) + 2 3051, 3032, 3041
123  * memalign(64) + 4 2911, 2896, 2915
124  * memalign(64) + 8 2545, 2554, 2550
125  * memalign(64) + 16 2543, 2572, 2563
126  * memalign(64) + 32 2546, 2545, 2571
127  * memalign(64) + 64 2570, 2533, 2558
128  *
129  * BTW, malloc seems to do 8-byte alignment by default here.
130  */
131 #else
132  ptr = malloc(size);
133 #endif
134  if(!ptr && !size) {
135  size = 1;
136  ptr= av_malloc(1);
137  }
138 #if CONFIG_MEMORY_POISONING
139  if (ptr)
140  memset(ptr, FF_MEMORY_POISON, size);
141 #endif
142  return ptr;
143 }
144 
145 void *av_realloc(void *ptr, size_t size)
146 {
147 #if CONFIG_MEMALIGN_HACK
148  int diff;
149 #endif
150 
151  /* let's disallow possibly ambiguous cases */
152  if (size > (max_alloc_size - 32))
153  return NULL;
154 
155 #if CONFIG_MEMALIGN_HACK
156  //FIXME this isn't aligned correctly, though it probably isn't needed
157  if (!ptr)
158  return av_malloc(size);
159  diff = ((char *)ptr)[-1];
160  av_assert0(diff>0 && diff<=ALIGN);
161  ptr = realloc((char *)ptr - diff, size + diff);
162  if (ptr)
163  ptr = (char *)ptr + diff;
164  return ptr;
165 #elif HAVE_ALIGNED_MALLOC
166  return _aligned_realloc(ptr, size + !size, ALIGN);
167 #else
168  return realloc(ptr, size + !size);
169 #endif
170 }
171 
172 void *av_realloc_f(void *ptr, size_t nelem, size_t elsize)
173 {
174  size_t size;
175  void *r;
176 
177  if (av_size_mult(elsize, nelem, &size)) {
178  av_free(ptr);
179  return NULL;
180  }
181  r = av_realloc(ptr, size);
182  if (!r)
183  av_free(ptr);
184  return r;
185 }
186 
187 int av_reallocp(void *ptr, size_t size)
188 {
189  void *val;
190 
191  if (!size) {
192  av_freep(ptr);
193  return 0;
194  }
195 
196  memcpy(&val, ptr, sizeof(val));
197  val = av_realloc(val, size);
198 
199  if (!val) {
200  av_freep(ptr);
201  return AVERROR(ENOMEM);
202  }
203 
204  memcpy(ptr, &val, sizeof(val));
205  return 0;
206 }
207 
208 void *av_realloc_array(void *ptr, size_t nmemb, size_t size)
209 {
210  if (!size || nmemb >= INT_MAX / size)
211  return NULL;
212  return av_realloc(ptr, nmemb * size);
213 }
214 
215 int av_reallocp_array(void *ptr, size_t nmemb, size_t size)
216 {
217  void *val;
218 
219  memcpy(&val, ptr, sizeof(val));
220  val = av_realloc_f(val, nmemb, size);
221  memcpy(ptr, &val, sizeof(val));
222  if (!val && nmemb && size)
223  return AVERROR(ENOMEM);
224 
225  return 0;
226 }
227 
228 void av_free(void *ptr)
229 {
230 #if CONFIG_MEMALIGN_HACK
231  if (ptr) {
232  int v= ((char *)ptr)[-1];
233  av_assert0(v>0 && v<=ALIGN);
234  free((char *)ptr - v);
235  }
236 #elif HAVE_ALIGNED_MALLOC
237  _aligned_free(ptr);
238 #else
239  free(ptr);
240 #endif
241 }
242 
243 void av_freep(void *arg)
244 {
245  void *val;
246 
247  memcpy(&val, arg, sizeof(val));
248  memcpy(arg, &(void *){ NULL }, sizeof(val));
249  av_free(val);
250 }
251 
252 void *av_mallocz(size_t size)
253 {
254  void *ptr = av_malloc(size);
255  if (ptr)
256  memset(ptr, 0, size);
257  return ptr;
258 }
259 
260 void *av_calloc(size_t nmemb, size_t size)
261 {
262  if (size <= 0 || nmemb >= INT_MAX / size)
263  return NULL;
264  return av_mallocz(nmemb * size);
265 }
266 
267 char *av_strdup(const char *s)
268 {
269  char *ptr = NULL;
270  if (s) {
271  size_t len = strlen(s) + 1;
272  ptr = av_realloc(NULL, len);
273  if (ptr)
274  memcpy(ptr, s, len);
275  }
276  return ptr;
277 }
278 
279 char *av_strndup(const char *s, size_t len)
280 {
281  char *ret = NULL, *end;
282 
283  if (!s)
284  return NULL;
285 
286  end = memchr(s, 0, len);
287  if (end)
288  len = end - s;
289 
290  ret = av_realloc(NULL, len + 1);
291  if (!ret)
292  return NULL;
293 
294  memcpy(ret, s, len);
295  ret[len] = 0;
296  return ret;
297 }
298 
299 void *av_memdup(const void *p, size_t size)
300 {
301  void *ptr = NULL;
302  if (p) {
303  ptr = av_malloc(size);
304  if (ptr)
305  memcpy(ptr, p, size);
306  }
307  return ptr;
308 }
309 
310 int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem)
311 {
312  void **tab;
313  memcpy(&tab, tab_ptr, sizeof(tab));
314 
315  FF_DYNARRAY_ADD(INT_MAX, sizeof(*tab), tab, *nb_ptr, {
316  tab[*nb_ptr] = elem;
317  memcpy(tab_ptr, &tab, sizeof(tab));
318  }, {
319  return AVERROR(ENOMEM);
320  });
321  return 0;
322 }
323 
324 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem)
325 {
326  void **tab;
327  memcpy(&tab, tab_ptr, sizeof(tab));
328 
329  FF_DYNARRAY_ADD(INT_MAX, sizeof(*tab), tab, *nb_ptr, {
330  tab[*nb_ptr] = elem;
331  memcpy(tab_ptr, &tab, sizeof(tab));
332  }, {
333  *nb_ptr = 0;
334  av_freep(tab_ptr);
335  });
336 }
337 
338 void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size,
339  const uint8_t *elem_data)
340 {
341  uint8_t *tab_elem_data = NULL;
342 
343  FF_DYNARRAY_ADD(INT_MAX, elem_size, *tab_ptr, *nb_ptr, {
344  tab_elem_data = (uint8_t *)*tab_ptr + (*nb_ptr) * elem_size;
345  if (elem_data)
346  memcpy(tab_elem_data, elem_data, elem_size);
347  else if (CONFIG_MEMORY_POISONING)
348  memset(tab_elem_data, FF_MEMORY_POISON, elem_size);
349  }, {
350  av_freep(tab_ptr);
351  *nb_ptr = 0;
352  });
353  return tab_elem_data;
354 }
355 
356 static void fill16(uint8_t *dst, int len)
357 {
358  uint32_t v = AV_RN16(dst - 2);
359 
360  v |= v << 16;
361 
362  while (len >= 4) {
363  AV_WN32(dst, v);
364  dst += 4;
365  len -= 4;
366  }
367 
368  while (len--) {
369  *dst = dst[-2];
370  dst++;
371  }
372 }
373 
374 static void fill24(uint8_t *dst, int len)
375 {
376 #if HAVE_BIGENDIAN
377  uint32_t v = AV_RB24(dst - 3);
378  uint32_t a = v << 8 | v >> 16;
379  uint32_t b = v << 16 | v >> 8;
380  uint32_t c = v << 24 | v;
381 #else
382  uint32_t v = AV_RL24(dst - 3);
383  uint32_t a = v | v << 24;
384  uint32_t b = v >> 8 | v << 16;
385  uint32_t c = v >> 16 | v << 8;
386 #endif
387 
388  while (len >= 12) {
389  AV_WN32(dst, a);
390  AV_WN32(dst + 4, b);
391  AV_WN32(dst + 8, c);
392  dst += 12;
393  len -= 12;
394  }
395 
396  if (len >= 4) {
397  AV_WN32(dst, a);
398  dst += 4;
399  len -= 4;
400  }
401 
402  if (len >= 4) {
403  AV_WN32(dst, b);
404  dst += 4;
405  len -= 4;
406  }
407 
408  while (len--) {
409  *dst = dst[-3];
410  dst++;
411  }
412 }
413 
414 static void fill32(uint8_t *dst, int len)
415 {
416  uint32_t v = AV_RN32(dst - 4);
417 
418  while (len >= 4) {
419  AV_WN32(dst, v);
420  dst += 4;
421  len -= 4;
422  }
423 
424  while (len--) {
425  *dst = dst[-4];
426  dst++;
427  }
428 }
429 
430 void av_memcpy_backptr(uint8_t *dst, int back, int cnt)
431 {
432  const uint8_t *src = &dst[-back];
433  if (!back)
434  return;
435 
436  if (back == 1) {
437  memset(dst, *src, cnt);
438  } else if (back == 2) {
439  fill16(dst, cnt);
440  } else if (back == 3) {
441  fill24(dst, cnt);
442  } else if (back == 4) {
443  fill32(dst, cnt);
444  } else {
445  if (cnt >= 16) {
446  int blocklen = back;
447  while (cnt > blocklen) {
448  memcpy(dst, src, blocklen);
449  dst += blocklen;
450  cnt -= blocklen;
451  blocklen <<= 1;
452  }
453  memcpy(dst, src, cnt);
454  return;
455  }
456  if (cnt >= 8) {
457  AV_COPY32U(dst, src);
458  AV_COPY32U(dst + 4, src + 4);
459  src += 8;
460  dst += 8;
461  cnt -= 8;
462  }
463  if (cnt >= 4) {
464  AV_COPY32U(dst, src);
465  src += 4;
466  dst += 4;
467  cnt -= 4;
468  }
469  if (cnt >= 2) {
470  AV_COPY16U(dst, src);
471  src += 2;
472  dst += 2;
473  cnt -= 2;
474  }
475  if (cnt)
476  *dst = *src;
477  }
478 }
479 
480 void *av_fast_realloc(void *ptr, unsigned int *size, size_t min_size)
481 {
482  if (min_size < *size)
483  return ptr;
484 
485  min_size = FFMAX(min_size + min_size / 16 + 32, min_size);
486 
487  ptr = av_realloc(ptr, min_size);
488  /* we could set this to the unmodified min_size but this is safer
489  * if the user lost the ptr and uses NULL now
490  */
491  if (!ptr)
492  min_size = 0;
493 
494  *size = min_size;
495 
496  return ptr;
497 }
498 
499 void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size)
500 {
501  ff_fast_malloc(ptr, size, min_size, 0);
502 }
503 
504 void av_fast_mallocz(void *ptr, unsigned int *size, size_t min_size)
505 {
506  ff_fast_malloc(ptr, size, min_size, 1);
507 }
#define NULL
Definition: coverity.c:32
void * av_realloc_f(void *ptr, size_t nelem, size_t elsize)
Allocate, reallocate, or free a block of memory.
Definition: mem.c:172
const char const char void * val
Definition: avisynth_c.h:771
const char * s
Definition: avisynth_c.h:768
void av_max_alloc(size_t max)
Set the maximum size that may be allocated in one block.
Definition: mem.c:73
void * av_realloc(void *ptr, size_t size)
Allocate, reallocate, or free a block of memory.
Definition: mem.c:145
Memory handling functions.
#define FF_MEMORY_POISON
Definition: internal.h:85
const char * b
Definition: vf_curves.c:113
Convenience header that includes libavutil's core.
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:252
#define src
Definition: vp8dsp.c:254
static void fill16(uint8_t *dst, int len)
Definition: mem.c:356
void * av_calloc(size_t nmemb, size_t size)
Non-inlined equivalent of av_mallocz_array().
Definition: mem.c:260
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
uint8_t
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
static void fill32(uint8_t *dst, int len)
Definition: mem.c:414
void av_memcpy_backptr(uint8_t *dst, int back, int cnt)
Overlapping memcpy() implementation.
Definition: mem.c:430
int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem)
Add an element to a dynamic array.
Definition: mem.c:310
ptrdiff_t size
Definition: opengl_enc.c:101
void * av_realloc_array(void *ptr, size_t nmemb, size_t size)
Definition: mem.c:208
#define AV_COPY16U(d, s)
Definition: intreadwrite.h:553
#define AVERROR(e)
Definition: error.h:43
void av_freep(void *arg)
Free a memory block which has been allocated with a function of av_malloc() or av_realloc() family...
Definition: mem.c:243
const char * r
Definition: vf_curves.c:111
const char * arg
Definition: jacosubdec.c:66
simple assert() macros that are a bit more flexible than ISO C assert().
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_RL24
Definition: bytestream.h:87
void * av_memdup(const void *p, size_t size)
Duplicate a buffer with av_malloc().
Definition: mem.c:299
#define FFMAX(a, b)
Definition: common.h:94
int av_reallocp_array(void *ptr, size_t nmemb, size_t size)
Definition: mem.c:215
void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size)
Allocate a buffer, reusing the given one if large enough.
Definition: mem.c:499
void av_fast_mallocz(void *ptr, unsigned int *size, size_t min_size)
Allocate and clear a buffer, reusing the given one if large enough.
Definition: mem.c:504
#define AV_COPY32U(d, s)
Definition: intreadwrite.h:557
void * av_fast_realloc(void *ptr, unsigned int *size, size_t min_size)
Reallocate the given buffer if it is not large enough, otherwise do nothing.
Definition: mem.c:480
const AVS_VideoInfo int align
Definition: avisynth_c.h:795
int av_reallocp(void *ptr, size_t size)
Allocate, reallocate, or free a block of memory through a pointer to a pointer.
Definition: mem.c:187
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:267
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_RB24
Definition: bytestream.h:87
void * av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size, const uint8_t *elem_data)
Add an element of size elem_size to a dynamic array.
Definition: mem.c:338
#define AV_RN16(p)
Definition: intreadwrite.h:360
#define ALIGN
Definition: mem.c:64
static size_t max_alloc_size
Definition: mem.c:71
#define AV_RN32(p)
Definition: intreadwrite.h:364
void av_free(void *ptr)
Free a memory block which has been allocated with a function of av_malloc() or av_realloc() family...
Definition: mem.c:228
static void fill24(uint8_t *dst, int len)
Definition: mem.c:374
void * av_malloc(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:77
#define FF_DYNARRAY_ADD(av_size_max, av_elt_size, av_array, av_size, av_success, av_failure)
Add an element of to a dynamic array.
Definition: dynarray.h:45
common internal and external API header
#define AV_WN32(p, v)
Definition: intreadwrite.h:376
static int av_size_mult(size_t a, size_t b, size_t *r)
Multiply two size_t values checking for overflow.
Definition: mem.h:665
static av_always_inline int diff(const uint32_t a, const uint32_t b)
void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem)
Add the pointer to an element to a dynamic array.
Definition: mem.c:324
int len
static AVCodec * c
static const struct twinvq_data tab
static int ff_fast_malloc(void *ptr, unsigned int *size, size_t min_size, int zero_realloc)
Definition: mem_internal.h:27
char * av_strndup(const char *s, size_t len)
Duplicate a substring of a string.
Definition: mem.c:279