libavutil/mem.c

   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 <stdatomic.h>
  35 #include <string.h>
  36 #if HAVE_MALLOC_H
  37 #include <malloc.h>
  38 #endif
  39
  40 #include "attributes.h"
  41 #include "avassert.h"
  42 #include "dynarray.h"
  43 #include "error.h"
  44 #include "internal.h"
  45 #include "intreadwrite.h"
  46 #include "macros.h"
  47 #include "mem.h"
  48
  49 #ifdef MALLOC_PREFIX
  50
  51 #define malloc         AV_JOIN(MALLOC_PREFIX, malloc)
  52 #define memalign       AV_JOIN(MALLOC_PREFIX, memalign)
  53 #define posix_memalign AV_JOIN(MALLOC_PREFIX, posix_memalign)
  54 #define realloc        AV_JOIN(MALLOC_PREFIX, realloc)
  55 #define free           AV_JOIN(MALLOC_PREFIX, free)
  56
  57 void *malloc(size_t size);
  58 void *memalign(size_t align, size_t size);
  59 int   posix_memalign(void **ptr, size_t align, size_t size);
  60 void *realloc(void *ptr, size_t size);
  61 void  free(void *ptr);
  62
  63 #endif /* MALLOC_PREFIX */
  64
  65 #define ALIGN (HAVE_SIMD_ALIGN_64 ? 64 : (HAVE_SIMD_ALIGN_32 ? 32 : 16))
  66
  67 #define FF_MEMORY_POISON 0x2a
  68
  69 /* NOTE: if you want to override these functions with your own
  70  * implementations (not recommended) you have to link libav* as
  71  * dynamic libraries and remove -Wl,-Bsymbolic from the linker flags.
  72  * Note that this will cost performance. */
  73
  74 static atomic_size_t max_alloc_size = INT_MAX;
  75
  76 void av_max_alloc(size_t max){
  77     atomic_store_explicit(&max_alloc_size, max, memory_order_relaxed);
  78 }
  79
  80 static int size_mult(size_t a, size_t b, size_t *r)
  81 {
  82     size_t t;
  83
  84 #if (!defined(__INTEL_COMPILER) && AV_GCC_VERSION_AT_LEAST(5,1)) || AV_HAS_BUILTIN(__builtin_mul_overflow)
  85     if (__builtin_mul_overflow(a, b, &t))
  86         return AVERROR(EINVAL);
  87 #else
  88     t = a * b;
  89     /* Hack inspired from glibc: don't try the division if nelem and elsize
  90      * are both less than sqrt(SIZE_MAX). */
  91     if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b)
  92         return AVERROR(EINVAL);
  93 #endif
  94     *r = t;
  95     return 0;
  96 }
  97
  98 void *av_malloc(size_t size)
  99 {
 100     void *ptr = NULL;
 101
 102     if (size > atomic_load_explicit(&max_alloc_size, memory_order_relaxed))
 103         return NULL;
 104
 105 #if HAVE_POSIX_MEMALIGN
 106     if (size) //OS X on SDK 10.6 has a broken posix_memalign implementation
 107     if (posix_memalign(&ptr, ALIGN, size))
 108         ptr = NULL;
 109 #elif HAVE_ALIGNED_MALLOC
 110     ptr = _aligned_malloc(size, ALIGN);
 111 #elif HAVE_MEMALIGN
 112 #ifndef __DJGPP__
 113     ptr = memalign(ALIGN, size);
 114 #else
 115     ptr = memalign(size, ALIGN);
 116 #endif
 117     /* Why 64?
 118      * Indeed, we should align it:
 119      *   on  4 for 386
 120      *   on 16 for 486
 121      *   on 32 for 586, PPro - K6-III
 122      *   on 64 for K7 (maybe for P3 too).
 123      * Because L1 and L2 caches are aligned on those values.
 124      * But I don't want to code such logic here!
 125      */
 126     /* Why 32?
 127      * For AVX ASM. SSE / NEON needs only 16.
 128      * Why not larger? Because I did not see a difference in benchmarks ...
 129      */
 130     /* benchmarks with P3
 131      * memalign(64) + 1          3071, 3051, 3032
 132      * memalign(64) + 2          3051, 3032, 3041
 133      * memalign(64) + 4          2911, 2896, 2915
 134      * memalign(64) + 8          2545, 2554, 2550
 135      * memalign(64) + 16         2543, 2572, 2563
 136      * memalign(64) + 32         2546, 2545, 2571
 137      * memalign(64) + 64         2570, 2533, 2558
 138      *
 139      * BTW, malloc seems to do 8-byte alignment by default here.
 140      */
 141 #else
 142     ptr = malloc(size);
 143 #endif
 144     if(!ptr && !size) {
 145         size = 1;
 146         ptr= av_malloc(1);
 147     }
 148 #if CONFIG_MEMORY_POISONING
 149     if (ptr)
 150         memset(ptr, FF_MEMORY_POISON, size);
 151 #endif
 152     return ptr;
 153 }
 154
 155 void *av_realloc(void *ptr, size_t size)
 156 {
 157     void *ret;
 158     if (size > atomic_load_explicit(&max_alloc_size, memory_order_relaxed))
 159         return NULL;
 160
 161 #if HAVE_ALIGNED_MALLOC
 162     ret = _aligned_realloc(ptr, size + !size, ALIGN);
 163 #else
 164     ret = realloc(ptr, size + !size);
 165 #endif
 166 #if CONFIG_MEMORY_POISONING
 167     if (ret && !ptr)
 168         memset(ret, FF_MEMORY_POISON, size);
 169 #endif
 170     return ret;
 171 }
 172
 173 void *av_realloc_f(void *ptr, size_t nelem, size_t elsize)
 174 {
 175     size_t size;
 176     void *r;
 177
 178     if (size_mult(elsize, nelem, &size)) {
 179         av_free(ptr);
 180         return NULL;
 181     }
 182     r = av_realloc(ptr, size);
 183     if (!r)
 184         av_free(ptr);
 185     return r;
 186 }
 187
 188 int av_reallocp(void *ptr, size_t size)
 189 {
 190     void *val;
 191
 192     if (!size) {
 193         av_freep(ptr);
 194         return 0;
 195     }
 196
 197     memcpy(&val, ptr, sizeof(val));
 198     val = av_realloc(val, size);
 199
 200     if (!val) {
 201         av_freep(ptr);
 202         return AVERROR(ENOMEM);
 203     }
 204
 205     memcpy(ptr, &val, sizeof(val));
 206     return 0;
 207 }
 208
 209 void *av_malloc_array(size_t nmemb, size_t size)
 210 {
 211     size_t result;
 212     if (size_mult(nmemb, size, &result) < 0)
 213         return NULL;
 214     return av_malloc(result);
 215 }
 216
 217 void *av_realloc_array(void *ptr, size_t nmemb, size_t size)
 218 {
 219     size_t result;
 220     if (size_mult(nmemb, size, &result) < 0)
 221         return NULL;
 222     return av_realloc(ptr, result);
 223 }
 224
 225 int av_reallocp_array(void *ptr, size_t nmemb, size_t size)
 226 {
 227     void *val;
 228
 229     memcpy(&val, ptr, sizeof(val));
 230     val = av_realloc_f(val, nmemb, size);
 231     memcpy(ptr, &val, sizeof(val));
 232     if (!val && nmemb && size)
 233         return AVERROR(ENOMEM);
 234
 235     return 0;
 236 }
 237
 238 void av_free(void *ptr)
 239 {
 240 #if HAVE_ALIGNED_MALLOC
 241     _aligned_free(ptr);
 242 #else
 243     free(ptr);
 244 #endif
 245 }
 246
 247 void av_freep(void *arg)
 248 {
 249     void *val;
 250
 251     memcpy(&val, arg, sizeof(val));
 252     memcpy(arg, &(void *){ NULL }, sizeof(val));
 253     av_free(val);
 254 }
 255
 256 void *av_mallocz(size_t size)
 257 {
 258     void *ptr = av_malloc(size);
 259     if (ptr)
 260         memset(ptr, 0, size);
 261     return ptr;
 262 }
 263
 264 void *av_calloc(size_t nmemb, size_t size)
 265 {
 266     size_t result;
 267     if (size_mult(nmemb, size, &result) < 0)
 268         return NULL;
 269     return av_mallocz(result);
 270 }
 271
 272 char *av_strdup(const char *s)
 273 {
 274     char *ptr = NULL;
 275     if (s) {
 276         size_t len = strlen(s) + 1;
 277         ptr = av_realloc(NULL, len);
 278         if (ptr)
 279             memcpy(ptr, s, len);
 280     }
 281     return ptr;
 282 }
 283
 284 char *av_strndup(const char *s, size_t len)
 285 {
 286     char *ret = NULL, *end;
 287
 288     if (!s)
 289         return NULL;
 290
 291     end = memchr(s, 0, len);
 292     if (end)
 293         len = end - s;
 294
 295     ret = av_realloc(NULL, len + 1);
 296     if (!ret)
 297         return NULL;
 298
 299     memcpy(ret, s, len);
 300     ret[len] = 0;
 301     return ret;
 302 }
 303
 304 void *av_memdup(const void *p, size_t size)
 305 {
 306     void *ptr = NULL;
 307     if (p) {
 308         ptr = av_malloc(size);
 309         if (ptr)
 310             memcpy(ptr, p, size);
 311     }
 312     return ptr;
 313 }
 314
 315 int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem)
 316 {
 317     void **tab;
 318     memcpy(&tab, tab_ptr, sizeof(tab));
 319
 320     FF_DYNARRAY_ADD(INT_MAX, sizeof(*tab), tab, *nb_ptr, {
 321         tab[*nb_ptr] = elem;
 322         memcpy(tab_ptr, &tab, sizeof(tab));
 323     }, {
 324         return AVERROR(ENOMEM);
 325     });
 326     return 0;
 327 }
 328
 329 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem)
 330 {
 331     void **tab;
 332     memcpy(&tab, tab_ptr, sizeof(tab));
 333
 334     FF_DYNARRAY_ADD(INT_MAX, sizeof(*tab), tab, *nb_ptr, {
 335         tab[*nb_ptr] = elem;
 336         memcpy(tab_ptr, &tab, sizeof(tab));
 337     }, {
 338         *nb_ptr = 0;
 339         av_freep(tab_ptr);
 340     });
 341 }
 342
 343 void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size,
 344                        const uint8_t *elem_data)
 345 {
 346     uint8_t *tab_elem_data = NULL;
 347
 348     FF_DYNARRAY_ADD(INT_MAX, elem_size, *tab_ptr, *nb_ptr, {
 349         tab_elem_data = (uint8_t *)*tab_ptr + (*nb_ptr) * elem_size;
 350         if (elem_data)
 351             memcpy(tab_elem_data, elem_data, elem_size);
 352         else if (CONFIG_MEMORY_POISONING)
 353             memset(tab_elem_data, FF_MEMORY_POISON, elem_size);
 354     }, {
 355         av_freep(tab_ptr);
 356         *nb_ptr = 0;
 357     });
 358     return tab_elem_data;
 359 }
 360
 361 static void fill16(uint8_t *dst, int len)
 362 {
 363     uint32_t v = AV_RN16(dst - 2);
 364
 365     v |= v << 16;
 366
 367     while (len >= 4) {
 368         AV_WN32(dst, v);
 369         dst += 4;
 370         len -= 4;
 371     }
 372
 373     while (len--) {
 374         *dst = dst[-2];
 375         dst++;
 376     }
 377 }
 378
 379 static void fill24(uint8_t *dst, int len)
 380 {
 381 #if HAVE_BIGENDIAN
 382     uint32_t v = AV_RB24(dst - 3);
 383     uint32_t a = v << 8  | v >> 16;
 384     uint32_t b = v << 16 | v >> 8;
 385     uint32_t c = v << 24 | v;
 386 #else
 387     uint32_t v = AV_RL24(dst - 3);
 388     uint32_t a = v       | v << 24;
 389     uint32_t b = v >> 8  | v << 16;
 390     uint32_t c = v >> 16 | v << 8;
 391 #endif
 392
 393     while (len >= 12) {
 394         AV_WN32(dst,     a);
 395         AV_WN32(dst + 4, b);
 396         AV_WN32(dst + 8, c);
 397         dst += 12;
 398         len -= 12;
 399     }
 400
 401     if (len >= 4) {
 402         AV_WN32(dst, a);
 403         dst += 4;
 404         len -= 4;
 405     }
 406
 407     if (len >= 4) {
 408         AV_WN32(dst, b);
 409         dst += 4;
 410         len -= 4;
 411     }
 412
 413     while (len--) {
 414         *dst = dst[-3];
 415         dst++;
 416     }
 417 }
 418
 419 static void fill32(uint8_t *dst, int len)
 420 {
 421     uint32_t v = AV_RN32(dst - 4);
 422
 423 #if HAVE_FAST_64BIT
 424     uint64_t v2= v + ((uint64_t)v<<32);
 425     while (len >= 32) {
 426         AV_WN64(dst   , v2);
 427         AV_WN64(dst+ 8, v2);
 428         AV_WN64(dst+16, v2);
 429         AV_WN64(dst+24, v2);
 430         dst += 32;
 431         len -= 32;
 432     }
 433 #endif
 434
 435     while (len >= 4) {
 436         AV_WN32(dst, v);
 437         dst += 4;
 438         len -= 4;
 439     }
 440
 441     while (len--) {
 442         *dst = dst[-4];
 443         dst++;
 444     }
 445 }
 446
 447 void av_memcpy_backptr(uint8_t *dst, int back, int cnt)
 448 {
 449     const uint8_t *src = &dst[-back];
 450     if (!back)
 451         return;
 452
 453     if (back == 1) {
 454         memset(dst, *src, cnt);
 455     } else if (back == 2) {
 456         fill16(dst, cnt);
 457     } else if (back == 3) {
 458         fill24(dst, cnt);
 459     } else if (back == 4) {
 460         fill32(dst, cnt);
 461     } else {
 462         if (cnt >= 16) {
 463             int blocklen = back;
 464             while (cnt > blocklen) {
 465                 memcpy(dst, src, blocklen);
 466                 dst       += blocklen;
 467                 cnt       -= blocklen;
 468                 blocklen <<= 1;
 469             }
 470             memcpy(dst, src, cnt);
 471             return;
 472         }
 473         if (cnt >= 8) {
 474             AV_COPY32U(dst,     src);
 475             AV_COPY32U(dst + 4, src + 4);
 476             src += 8;
 477             dst += 8;
 478             cnt -= 8;
 479         }
 480         if (cnt >= 4) {
 481             AV_COPY32U(dst, src);
 482             src += 4;
 483             dst += 4;
 484             cnt -= 4;
 485         }
 486         if (cnt >= 2) {
 487             AV_COPY16U(dst, src);
 488             src += 2;
 489             dst += 2;
 490             cnt -= 2;
 491         }
 492         if (cnt)
 493             *dst = *src;
 494     }
 495 }
 496
 497 void *av_fast_realloc(void *ptr, unsigned int *size, size_t min_size)
 498 {
 499     size_t max_size;
 500
 501     if (min_size <= *size)
 502         return ptr;
 503
 504     max_size = atomic_load_explicit(&max_alloc_size, memory_order_relaxed);
 505     /* *size is an unsigned, so the real maximum is <= UINT_MAX. */
 506     max_size = FFMIN(max_size, UINT_MAX);
 507
 508     if (min_size > max_size) {
 509         *size = 0;
 510         return NULL;
 511     }
 512
 513     min_size = FFMIN(max_size, FFMAX(min_size + min_size / 16 + 32, min_size));
 514
 515     ptr = av_realloc(ptr, min_size);
 516     /* we could set this to the unmodified min_size but this is safer
 517      * if the user lost the ptr and uses NULL now
 518      */
 519     if (!ptr)
 520         min_size = 0;
 521
 522     *size = min_size;
 523
 524     return ptr;
 525 }
 526
 527 static inline void fast_malloc(void *ptr, unsigned int *size, size_t min_size, int zero_realloc)
 528 {
 529     size_t max_size;
 530     void *val;
 531
 532     memcpy(&val, ptr, sizeof(val));
 533     if (min_size <= *size) {
 534         av_assert0(val || !min_size);
 535         return;
 536     }
 537
 538     max_size = atomic_load_explicit(&max_alloc_size, memory_order_relaxed);
 539     /* *size is an unsigned, so the real maximum is <= UINT_MAX. */
 540     max_size = FFMIN(max_size, UINT_MAX);
 541
 542     if (min_size > max_size) {
 543         av_freep(ptr);
 544         *size = 0;
 545         return;
 546     }
 547     min_size = FFMIN(max_size, FFMAX(min_size + min_size / 16 + 32, min_size));
 548     av_freep(ptr);
 549     val = zero_realloc ? av_mallocz(min_size) : av_malloc(min_size);
 550     memcpy(ptr, &val, sizeof(val));
 551     if (!val)
 552         min_size = 0;
 553     *size = min_size;
 554     return;
 555 }
 556
 557 void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size)
 558 {
 559     fast_malloc(ptr, size, min_size, 0);
 560 }
 561
 562 void av_fast_mallocz(void *ptr, unsigned int *size, size_t min_size)
 563 {
 564     fast_malloc(ptr, size, min_size, 1);
 565 }
 566
 567 int av_size_mult(size_t a, size_t b, size_t *r)
 568 {
 569     return size_mult(a, b, r);
 570 }