FFmpeg  4.3
mem.c
Go to the documentation of this file.
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_AVX512 ? 64 : (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){
75 }
76 
77 void *av_malloc(size_t size)
78 {
79  void *ptr = NULL;
80 
81  /* let's disallow possibly ambiguous cases */
82  if (size > (max_alloc_size - 32))
83  return NULL;
84 
85 #if HAVE_POSIX_MEMALIGN
86  if (size) //OS X on SDK 10.6 has a broken posix_memalign implementation
87  if (posix_memalign(&ptr, ALIGN, size))
88  ptr = NULL;
89 #elif HAVE_ALIGNED_MALLOC
90  ptr = _aligned_malloc(size, ALIGN);
91 #elif HAVE_MEMALIGN
92 #ifndef __DJGPP__
93  ptr = memalign(ALIGN, size);
94 #else
95  ptr = memalign(size, ALIGN);
96 #endif
97  /* Why 64?
98  * Indeed, we should align it:
99  * on 4 for 386
100  * on 16 for 486
101  * on 32 for 586, PPro - K6-III
102  * on 64 for K7 (maybe for P3 too).
103  * Because L1 and L2 caches are aligned on those values.
104  * But I don't want to code such logic here!
105  */
106  /* Why 32?
107  * For AVX ASM. SSE / NEON needs only 16.
108  * Why not larger? Because I did not see a difference in benchmarks ...
109  */
110  /* benchmarks with P3
111  * memalign(64) + 1 3071, 3051, 3032
112  * memalign(64) + 2 3051, 3032, 3041
113  * memalign(64) + 4 2911, 2896, 2915
114  * memalign(64) + 8 2545, 2554, 2550
115  * memalign(64) + 16 2543, 2572, 2563
116  * memalign(64) + 32 2546, 2545, 2571
117  * memalign(64) + 64 2570, 2533, 2558
118  *
119  * BTW, malloc seems to do 8-byte alignment by default here.
120  */
121 #else
122  ptr = malloc(size);
123 #endif
124  if(!ptr && !size) {
125  size = 1;
126  ptr= av_malloc(1);
127  }
128 #if CONFIG_MEMORY_POISONING
129  if (ptr)
130  memset(ptr, FF_MEMORY_POISON, size);
131 #endif
132  return ptr;
133 }
134 
135 void *av_realloc(void *ptr, size_t size)
136 {
137  /* let's disallow possibly ambiguous cases */
138  if (size > (max_alloc_size - 32))
139  return NULL;
140 
141 #if HAVE_ALIGNED_MALLOC
142  return _aligned_realloc(ptr, size + !size, ALIGN);
143 #else
144  return realloc(ptr, size + !size);
145 #endif
146 }
147 
148 void *av_realloc_f(void *ptr, size_t nelem, size_t elsize)
149 {
150  size_t size;
151  void *r;
152 
153  if (av_size_mult(elsize, nelem, &size)) {
154  av_free(ptr);
155  return NULL;
156  }
157  r = av_realloc(ptr, size);
158  if (!r)
159  av_free(ptr);
160  return r;
161 }
162 
163 int av_reallocp(void *ptr, size_t size)
164 {
165  void *val;
166 
167  if (!size) {
168  av_freep(ptr);
169  return 0;
170  }
171 
172  memcpy(&val, ptr, sizeof(val));
173  val = av_realloc(val, size);
174 
175  if (!val) {
176  av_freep(ptr);
177  return AVERROR(ENOMEM);
178  }
179 
180  memcpy(ptr, &val, sizeof(val));
181  return 0;
182 }
183 
184 void *av_malloc_array(size_t nmemb, size_t size)
185 {
186  size_t result;
187  if (av_size_mult(nmemb, size, &result) < 0)
188  return NULL;
189  return av_malloc(result);
190 }
191 
192 void *av_mallocz_array(size_t nmemb, size_t size)
193 {
194  size_t result;
195  if (av_size_mult(nmemb, size, &result) < 0)
196  return NULL;
197  return av_mallocz(result);
198 }
199 
200 void *av_realloc_array(void *ptr, size_t nmemb, size_t size)
201 {
202  size_t result;
203  if (av_size_mult(nmemb, size, &result) < 0)
204  return NULL;
205  return av_realloc(ptr, result);
206 }
207 
208 int av_reallocp_array(void *ptr, size_t nmemb, size_t size)
209 {
210  void *val;
211 
212  memcpy(&val, ptr, sizeof(val));
213  val = av_realloc_f(val, nmemb, size);
214  memcpy(ptr, &val, sizeof(val));
215  if (!val && nmemb && size)
216  return AVERROR(ENOMEM);
217 
218  return 0;
219 }
220 
221 void av_free(void *ptr)
222 {
223 #if HAVE_ALIGNED_MALLOC
224  _aligned_free(ptr);
225 #else
226  free(ptr);
227 #endif
228 }
229 
230 void av_freep(void *arg)
231 {
232  void *val;
233 
234  memcpy(&val, arg, sizeof(val));
235  memcpy(arg, &(void *){ NULL }, sizeof(val));
236  av_free(val);
237 }
238 
239 void *av_mallocz(size_t size)
240 {
241  void *ptr = av_malloc(size);
242  if (ptr)
243  memset(ptr, 0, size);
244  return ptr;
245 }
246 
247 void *av_calloc(size_t nmemb, size_t size)
248 {
249  size_t result;
250  if (av_size_mult(nmemb, size, &result) < 0)
251  return NULL;
252  return av_mallocz(result);
253 }
254 
255 char *av_strdup(const char *s)
256 {
257  char *ptr = NULL;
258  if (s) {
259  size_t len = strlen(s) + 1;
260  ptr = av_realloc(NULL, len);
261  if (ptr)
262  memcpy(ptr, s, len);
263  }
264  return ptr;
265 }
266 
267 char *av_strndup(const char *s, size_t len)
268 {
269  char *ret = NULL, *end;
270 
271  if (!s)
272  return NULL;
273 
274  end = memchr(s, 0, len);
275  if (end)
276  len = end - s;
277 
278  ret = av_realloc(NULL, len + 1);
279  if (!ret)
280  return NULL;
281 
282  memcpy(ret, s, len);
283  ret[len] = 0;
284  return ret;
285 }
286 
287 void *av_memdup(const void *p, size_t size)
288 {
289  void *ptr = NULL;
290  if (p) {
291  ptr = av_malloc(size);
292  if (ptr)
293  memcpy(ptr, p, size);
294  }
295  return ptr;
296 }
297 
298 int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem)
299 {
300  void **tab;
301  memcpy(&tab, tab_ptr, sizeof(tab));
302 
303  FF_DYNARRAY_ADD(INT_MAX, sizeof(*tab), tab, *nb_ptr, {
304  tab[*nb_ptr] = elem;
305  memcpy(tab_ptr, &tab, sizeof(tab));
306  }, {
307  return AVERROR(ENOMEM);
308  });
309  return 0;
310 }
311 
312 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem)
313 {
314  void **tab;
315  memcpy(&tab, tab_ptr, sizeof(tab));
316 
317  FF_DYNARRAY_ADD(INT_MAX, sizeof(*tab), tab, *nb_ptr, {
318  tab[*nb_ptr] = elem;
319  memcpy(tab_ptr, &tab, sizeof(tab));
320  }, {
321  *nb_ptr = 0;
322  av_freep(tab_ptr);
323  });
324 }
325 
326 void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size,
327  const uint8_t *elem_data)
328 {
329  uint8_t *tab_elem_data = NULL;
330 
331  FF_DYNARRAY_ADD(INT_MAX, elem_size, *tab_ptr, *nb_ptr, {
332  tab_elem_data = (uint8_t *)*tab_ptr + (*nb_ptr) * elem_size;
333  if (elem_data)
334  memcpy(tab_elem_data, elem_data, elem_size);
335  else if (CONFIG_MEMORY_POISONING)
336  memset(tab_elem_data, FF_MEMORY_POISON, elem_size);
337  }, {
338  av_freep(tab_ptr);
339  *nb_ptr = 0;
340  });
341  return tab_elem_data;
342 }
343 
344 static void fill16(uint8_t *dst, int len)
345 {
346  uint32_t v = AV_RN16(dst - 2);
347 
348  v |= v << 16;
349 
350  while (len >= 4) {
351  AV_WN32(dst, v);
352  dst += 4;
353  len -= 4;
354  }
355 
356  while (len--) {
357  *dst = dst[-2];
358  dst++;
359  }
360 }
361 
362 static void fill24(uint8_t *dst, int len)
363 {
364 #if HAVE_BIGENDIAN
365  uint32_t v = AV_RB24(dst - 3);
366  uint32_t a = v << 8 | v >> 16;
367  uint32_t b = v << 16 | v >> 8;
368  uint32_t c = v << 24 | v;
369 #else
370  uint32_t v = AV_RL24(dst - 3);
371  uint32_t a = v | v << 24;
372  uint32_t b = v >> 8 | v << 16;
373  uint32_t c = v >> 16 | v << 8;
374 #endif
375 
376  while (len >= 12) {
377  AV_WN32(dst, a);
378  AV_WN32(dst + 4, b);
379  AV_WN32(dst + 8, c);
380  dst += 12;
381  len -= 12;
382  }
383 
384  if (len >= 4) {
385  AV_WN32(dst, a);
386  dst += 4;
387  len -= 4;
388  }
389 
390  if (len >= 4) {
391  AV_WN32(dst, b);
392  dst += 4;
393  len -= 4;
394  }
395 
396  while (len--) {
397  *dst = dst[-3];
398  dst++;
399  }
400 }
401 
402 static void fill32(uint8_t *dst, int len)
403 {
404  uint32_t v = AV_RN32(dst - 4);
405 
406 #if HAVE_FAST_64BIT
407  uint64_t v2= v + ((uint64_t)v<<32);
408  while (len >= 32) {
409  AV_WN64(dst , v2);
410  AV_WN64(dst+ 8, v2);
411  AV_WN64(dst+16, v2);
412  AV_WN64(dst+24, v2);
413  dst += 32;
414  len -= 32;
415  }
416 #endif
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  if (min_size > max_alloc_size - 32) {
486  *size = 0;
487  return NULL;
488  }
489 
490  min_size = FFMIN(max_alloc_size - 32, FFMAX(min_size + min_size / 16 + 32, min_size));
491 
492  ptr = av_realloc(ptr, min_size);
493  /* we could set this to the unmodified min_size but this is safer
494  * if the user lost the ptr and uses NULL now
495  */
496  if (!ptr)
497  min_size = 0;
498 
499  *size = min_size;
500 
501  return ptr;
502 }
503 
504 void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size)
505 {
506  ff_fast_malloc(ptr, size, min_size, 0);
507 }
508 
509 void av_fast_mallocz(void *ptr, unsigned int *size, size_t min_size)
510 {
511  ff_fast_malloc(ptr, size, min_size, 1);
512 }
#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:148
void * av_realloc(void *ptr, size_t size)
Allocate, reallocate, or free a block of memory.
Definition: mem.c:135
int size
void av_max_alloc(size_t max)
Set the maximum size that may be allocated in one block.
Definition: mem.c:73
Memory handling functions.
#define FF_MEMORY_POISON
Definition: internal.h:89
const char * b
Definition: vf_curves.c:116
#define AV_RB24
Definition: intreadwrite.h:64
Convenience header that includes libavutil&#39;s core.
static void fill16(uint8_t *dst, int len)
Definition: mem.c:344
void * av_calloc(size_t nmemb, size_t size)
Non-inlined equivalent of av_mallocz_array().
Definition: mem.c:247
uint8_t
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
static void fill32(uint8_t *dst, int len)
Definition: mem.c:402
void av_memcpy_backptr(uint8_t *dst, int back, int cnt)
Overlapping memcpy() implementation.
Definition: mem.c:430
#define max(a, b)
Definition: cuda_runtime.h:33
int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem)
Add an element to a dynamic array.
Definition: mem.c:298
void * av_realloc_array(void *ptr, size_t nmemb, size_t size)
Allocate, reallocate, or free an array.
Definition: mem.c:200
#define src
Definition: vp8dsp.c:254
#define AV_COPY16U(d, s)
Definition: intreadwrite.h:568
#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:230
const char * r
Definition: vf_curves.c:114
const char * arg
Definition: jacosubdec.c:66
simple assert() macros that are a bit more flexible than ISO C assert().
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:239
void * av_memdup(const void *p, size_t size)
Duplicate a buffer with av_malloc().
Definition: mem.c:287
#define FFMAX(a, b)
Definition: common.h:94
int av_reallocp_array(void *ptr, size_t nmemb, size_t size)
Allocate, reallocate, or free an array through a pointer to a pointer.
Definition: mem.c:208
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:504
void * av_malloc_array(size_t nmemb, size_t size)
Allocate a memory block for an array with av_malloc().
Definition: mem.c:184
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:509
#define FFMIN(a, b)
Definition: common.h:96
#define AV_COPY32U(d, s)
Definition: intreadwrite.h:572
#define s(width, name)
Definition: cbs_vp9.c:257
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
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:163
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:255
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:326
#define AV_RN16(p)
Definition: intreadwrite.h:360
#define ALIGN
Definition: mem.c:64
#define CONFIG_MEMORY_POISONING
Definition: config.h:589
static size_t max_alloc_size
Definition: mem.c:71
#define AV_RN32(p)
Definition: intreadwrite.h:364
#define AV_RL24
Definition: intreadwrite.h:78
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:221
static void fill24(uint8_t *dst, int len)
Definition: mem.c:362
#define FF_DYNARRAY_ADD(av_size_max, av_elt_size, av_array, av_size, av_success, av_failure)
Add an element to a dynamic array.
Definition: dynarray.h:45
common internal and external API header
#define AV_WN32(p, v)
Definition: intreadwrite.h:376
static double c[64]
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:669
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:312
int len
static const struct twinvq_data tab
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
static double val(void *priv, double ch)
Definition: aeval.c:76
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:267
void * av_mallocz_array(size_t nmemb, size_t size)
Allocate a memory block for an array with av_mallocz().
Definition: mem.c:192
#define AV_WN64(p, v)
Definition: intreadwrite.h:380