src/png/pngmem.c

   1
   2 /* pngmem.c - stub functions for memory allocation
   3  *
   4  * Last changed in libpng 1.2.30 [August 15, 2008]
   5  * For conditions of distribution and use, see copyright notice in png.h
   6  * Copyright (c) 1998-2008 Glenn Randers-Pehrson
   7  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
   8  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
   9  *
  10  * This file provides a location for all memory allocation.  Users who
  11  * need special memory handling are expected to supply replacement
  12  * functions for png_malloc() and png_free(), and to use
  13  * png_create_read_struct_2() and png_create_write_struct_2() to
  14  * identify the replacement functions.
  15  */
  16
  17 #define PNG_INTERNAL
  18 #include "png.h"
  19 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
  20
  21 /* Borland DOS special memory handler */
  22 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
  23 /* if you change this, be sure to change the one in png.h also */
  24
  25 /* Allocate memory for a png_struct.  The malloc and memset can be replaced
  26    by a single call to calloc() if this is thought to improve performance. */
  27 png_voidp /* PRIVATE */
  28 png_create_struct(int type)
  29 {
  30 #ifdef PNG_USER_MEM_SUPPORTED
  31    return (png_create_struct_2(type, png_malloc_ptr_NULL, png_voidp_NULL));
  32 }
  33
  34 /* Alternate version of png_create_struct, for use with user-defined malloc. */
  35 png_voidp /* PRIVATE */
  36 png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
  37 {
  38 #endif /* PNG_USER_MEM_SUPPORTED */
  39    png_size_t size;
  40    png_voidp struct_ptr;
  41
  42    if (type == PNG_STRUCT_INFO)
  43      size = png_sizeof(png_info);
  44    else if (type == PNG_STRUCT_PNG)
  45      size = png_sizeof(png_struct);
  46    else
  47      return (png_get_copyright(NULL));
  48
  49 #ifdef PNG_USER_MEM_SUPPORTED
  50    if (malloc_fn != NULL)
  51    {
  52       png_struct dummy_struct;
  53       png_structp png_ptr = &dummy_struct;
  54       png_ptr->mem_ptr=mem_ptr;
  55       struct_ptr = (*(malloc_fn))(png_ptr, (png_uint_32)size);
  56    }
  57    else
  58 #endif /* PNG_USER_MEM_SUPPORTED */
  59       struct_ptr = (png_voidp)farmalloc(size);
  60    if (struct_ptr != NULL)
  61       png_memset(struct_ptr, 0, size);
  62    return (struct_ptr);
  63 }
  64
  65 /* Free memory allocated by a png_create_struct() call */
  66 void /* PRIVATE */
  67 png_destroy_struct(png_voidp struct_ptr)
  68 {
  69 #ifdef PNG_USER_MEM_SUPPORTED
  70    png_destroy_struct_2(struct_ptr, png_free_ptr_NULL, png_voidp_NULL);
  71 }
  72
  73 /* Free memory allocated by a png_create_struct() call */
  74 void /* PRIVATE */
  75 png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
  76     png_voidp mem_ptr)
  77 {
  78 #endif
  79    if (struct_ptr != NULL)
  80    {
  81 #ifdef PNG_USER_MEM_SUPPORTED
  82       if (free_fn != NULL)
  83       {
  84          png_struct dummy_struct;
  85          png_structp png_ptr = &dummy_struct;
  86          png_ptr->mem_ptr=mem_ptr;
  87          (*(free_fn))(png_ptr, struct_ptr);
  88          return;
  89       }
  90 #endif /* PNG_USER_MEM_SUPPORTED */
  91       farfree (struct_ptr);
  92    }
  93 }
  94
  95 /* Allocate memory.  For reasonable files, size should never exceed
  96  * 64K.  However, zlib may allocate more then 64K if you don't tell
  97  * it not to.  See zconf.h and png.h for more information. zlib does
  98  * need to allocate exactly 64K, so whatever you call here must
  99  * have the ability to do that.
 100  *
 101  * Borland seems to have a problem in DOS mode for exactly 64K.
 102  * It gives you a segment with an offset of 8 (perhaps to store its
 103  * memory stuff).  zlib doesn't like this at all, so we have to
 104  * detect and deal with it.  This code should not be needed in
 105  * Windows or OS/2 modes, and only in 16 bit mode.  This code has
 106  * been updated by Alexander Lehmann for version 0.89 to waste less
 107  * memory.
 108  *
 109  * Note that we can't use png_size_t for the "size" declaration,
 110  * since on some systems a png_size_t is a 16-bit quantity, and as a
 111  * result, we would be truncating potentially larger memory requests
 112  * (which should cause a fatal error) and introducing major problems.
 113  */
 114
 115 png_voidp PNGAPI
 116 png_malloc(png_structp png_ptr, png_uint_32 size)
 117 {
 118    png_voidp ret;
 119
 120    if (png_ptr == NULL || size == 0)
 121       return (NULL);
 122
 123 #ifdef PNG_USER_MEM_SUPPORTED
 124    if (png_ptr->malloc_fn != NULL)
 125        ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
 126    else
 127        ret = (png_malloc_default(png_ptr, size));
 128    if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
 129        png_error(png_ptr, "Out of memory!");
 130    return (ret);
 131 }
 132
 133 png_voidp PNGAPI
 134 png_malloc_default(png_structp png_ptr, png_uint_32 size)
 135 {
 136    png_voidp ret;
 137 #endif /* PNG_USER_MEM_SUPPORTED */
 138
 139    if (png_ptr == NULL || size == 0)
 140       return (NULL);
 141
 142 #ifdef PNG_MAX_MALLOC_64K
 143    if (size > (png_uint_32)65536L)
 144    {
 145       png_warning(png_ptr, "Cannot Allocate > 64K");
 146       ret = NULL;
 147    }
 148    else
 149 #endif
 150
 151    if (size != (size_t)size)
 152      ret = NULL;
 153    else if (size == (png_uint_32)65536L)
 154    {
 155       if (png_ptr->offset_table == NULL)
 156       {
 157          /* try to see if we need to do any of this fancy stuff */
 158          ret = farmalloc(size);
 159          if (ret == NULL || ((png_size_t)ret & 0xffff))
 160          {
 161             int num_blocks;
 162             png_uint_32 total_size;
 163             png_bytep table;
 164             int i;
 165             png_byte huge * hptr;
 166
 167             if (ret != NULL)
 168             {
 169                farfree(ret);
 170                ret = NULL;
 171             }
 172
 173             if (png_ptr->zlib_window_bits > 14)
 174                num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
 175             else
 176                num_blocks = 1;
 177             if (png_ptr->zlib_mem_level >= 7)
 178                num_blocks += (int)(1 << (png_ptr->zlib_mem_level - 7));
 179             else
 180                num_blocks++;
 181
 182             total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks+16;
 183
 184             table = farmalloc(total_size);
 185
 186             if (table == NULL)
 187             {
 188 #ifndef PNG_USER_MEM_SUPPORTED
 189                if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
 190                   png_error(png_ptr, "Out Of Memory."); /* Note "O" and "M" */
 191                else
 192                   png_warning(png_ptr, "Out Of Memory.");
 193 #endif
 194                return (NULL);
 195             }
 196
 197             if ((png_size_t)table & 0xfff0)
 198             {
 199 #ifndef PNG_USER_MEM_SUPPORTED
 200                if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
 201                   png_error(png_ptr,
 202                     "Farmalloc didn't return normalized pointer");
 203                else
 204                   png_warning(png_ptr,
 205                     "Farmalloc didn't return normalized pointer");
 206 #endif
 207                return (NULL);
 208             }
 209
 210             png_ptr->offset_table = table;
 211             png_ptr->offset_table_ptr = farmalloc(num_blocks *
 212                png_sizeof(png_bytep));
 213
 214             if (png_ptr->offset_table_ptr == NULL)
 215             {
 216 #ifndef PNG_USER_MEM_SUPPORTED
 217                if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
 218                   png_error(png_ptr, "Out Of memory."); /* Note "O" and "M" */
 219                else
 220                   png_warning(png_ptr, "Out Of memory.");
 221 #endif
 222                return (NULL);
 223             }
 224
 225             hptr = (png_byte huge *)table;
 226             if ((png_size_t)hptr & 0xf)
 227             {
 228                hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
 229                hptr = hptr + 16L;  /* "hptr += 16L" fails on Turbo C++ 3.0 */
 230             }
 231             for (i = 0; i < num_blocks; i++)
 232             {
 233                png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
 234                hptr = hptr + (png_uint_32)65536L;  /* "+=" fails on TC++3.0 */
 235             }
 236
 237             png_ptr->offset_table_number = num_blocks;
 238             png_ptr->offset_table_count = 0;
 239             png_ptr->offset_table_count_free = 0;
 240          }
 241       }
 242
 243       if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
 244       {
 245 #ifndef PNG_USER_MEM_SUPPORTED
 246          if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
 247             png_error(png_ptr, "Out of Memory."); /* Note "o" and "M" */
 248          else
 249             png_warning(png_ptr, "Out of Memory.");
 250 #endif
 251          return (NULL);
 252       }
 253
 254       ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
 255    }
 256    else
 257       ret = farmalloc(size);
 258
 259 #ifndef PNG_USER_MEM_SUPPORTED
 260    if (ret == NULL)
 261    {
 262       if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
 263          png_error(png_ptr, "Out of memory."); /* Note "o" and "m" */
 264       else
 265          png_warning(png_ptr, "Out of memory."); /* Note "o" and "m" */
 266    }
 267 #endif
 268
 269    return (ret);
 270 }
 271
 272 /* free a pointer allocated by png_malloc().  In the default
 273    configuration, png_ptr is not used, but is passed in case it
 274    is needed.  If ptr is NULL, return without taking any action. */
 275
 276 void PNGAPI
 277 png_free(png_structp png_ptr, png_voidp ptr)
 278 {
 279    if (png_ptr == NULL || ptr == NULL)
 280       return;
 281
 282 #ifdef PNG_USER_MEM_SUPPORTED
 283    if (png_ptr->free_fn != NULL)
 284    {
 285       (*(png_ptr->free_fn))(png_ptr, ptr);
 286       return;
 287    }
 288    else png_free_default(png_ptr, ptr);
 289 }
 290
 291 void PNGAPI
 292 png_free_default(png_structp png_ptr, png_voidp ptr)
 293 {
 294 #endif /* PNG_USER_MEM_SUPPORTED */
 295
 296    if (png_ptr == NULL || ptr == NULL) return;
 297
 298    if (png_ptr->offset_table != NULL)
 299    {
 300       int i;
 301
 302       for (i = 0; i < png_ptr->offset_table_count; i++)
 303       {
 304          if (ptr == png_ptr->offset_table_ptr[i])
 305          {
 306             ptr = NULL;
 307             png_ptr->offset_table_count_free++;
 308             break;
 309          }
 310       }
 311       if (png_ptr->offset_table_count_free == png_ptr->offset_table_count)
 312       {
 313          farfree(png_ptr->offset_table);
 314          farfree(png_ptr->offset_table_ptr);
 315          png_ptr->offset_table = NULL;
 316          png_ptr->offset_table_ptr = NULL;
 317       }
 318    }
 319
 320    if (ptr != NULL)
 321    {
 322       farfree(ptr);
 323    }
 324 }
 325
 326 #else /* Not the Borland DOS special memory handler */
 327
 328 /* Allocate memory for a png_struct or a png_info.  The malloc and
 329    memset can be replaced by a single call to calloc() if this is thought
 330    to improve performance noticably. */
 331 png_voidp /* PRIVATE */
 332 png_create_struct(int type)
 333 {
 334 #ifdef PNG_USER_MEM_SUPPORTED
 335    return (png_create_struct_2(type, png_malloc_ptr_NULL, png_voidp_NULL));
 336 }
 337
 338 /* Allocate memory for a png_struct or a png_info.  The malloc and
 339    memset can be replaced by a single call to calloc() if this is thought
 340    to improve performance noticably. */
 341 png_voidp /* PRIVATE */
 342 png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
 343 {
 344 #endif /* PNG_USER_MEM_SUPPORTED */
 345    png_size_t size;
 346    png_voidp struct_ptr;
 347
 348    if (type == PNG_STRUCT_INFO)
 349       size = png_sizeof(png_info);
 350    else if (type == PNG_STRUCT_PNG)
 351       size = png_sizeof(png_struct);
 352    else
 353       return (NULL);
 354
 355 #ifdef PNG_USER_MEM_SUPPORTED
 356    if (malloc_fn != NULL)
 357    {
 358       png_struct dummy_struct;
 359       png_structp png_ptr = &dummy_struct;
 360       png_ptr->mem_ptr=mem_ptr;
 361       struct_ptr = (*(malloc_fn))(png_ptr, size);
 362       if (struct_ptr != NULL)
 363          png_memset(struct_ptr, 0, size);
 364       return (struct_ptr);
 365    }
 366 #endif /* PNG_USER_MEM_SUPPORTED */
 367
 368 #if defined(__TURBOC__) && !defined(__FLAT__)
 369    struct_ptr = (png_voidp)farmalloc(size);
 370 #else
 371 # if defined(_MSC_VER) && defined(MAXSEG_64K)
 372    struct_ptr = (png_voidp)halloc(size, 1);
 373 # else
 374    struct_ptr = (png_voidp)malloc(size);
 375 # endif
 376 #endif
 377    if (struct_ptr != NULL)
 378       png_memset(struct_ptr, 0, size);
 379
 380    return (struct_ptr);
 381 }
 382
 383
 384 /* Free memory allocated by a png_create_struct() call */
 385 void /* PRIVATE */
 386 png_destroy_struct(png_voidp struct_ptr)
 387 {
 388 #ifdef PNG_USER_MEM_SUPPORTED
 389    png_destroy_struct_2(struct_ptr, png_free_ptr_NULL, png_voidp_NULL);
 390 }
 391
 392 /* Free memory allocated by a png_create_struct() call */
 393 void /* PRIVATE */
 394 png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
 395     png_voidp mem_ptr)
 396 {
 397 #endif /* PNG_USER_MEM_SUPPORTED */
 398    if (struct_ptr != NULL)
 399    {
 400 #ifdef PNG_USER_MEM_SUPPORTED
 401       if (free_fn != NULL)
 402       {
 403          png_struct dummy_struct;
 404          png_structp png_ptr = &dummy_struct;
 405          png_ptr->mem_ptr=mem_ptr;
 406          (*(free_fn))(png_ptr, struct_ptr);
 407          return;
 408       }
 409 #endif /* PNG_USER_MEM_SUPPORTED */
 410 #if defined(__TURBOC__) && !defined(__FLAT__)
 411       farfree(struct_ptr);
 412 #else
 413 # if defined(_MSC_VER) && defined(MAXSEG_64K)
 414       hfree(struct_ptr);
 415 # else
 416       free(struct_ptr);
 417 # endif
 418 #endif
 419    }
 420 }
 421
 422 /* Allocate memory.  For reasonable files, size should never exceed
 423    64K.  However, zlib may allocate more then 64K if you don't tell
 424    it not to.  See zconf.h and png.h for more information.  zlib does
 425    need to allocate exactly 64K, so whatever you call here must
 426    have the ability to do that. */
 427
 428 png_voidp PNGAPI
 429 png_malloc(png_structp png_ptr, png_uint_32 size)
 430 {
 431    png_voidp ret;
 432
 433 #ifdef PNG_USER_MEM_SUPPORTED
 434    if (png_ptr == NULL || size == 0)
 435       return (NULL);
 436
 437    if (png_ptr->malloc_fn != NULL)
 438        ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
 439    else
 440        ret = (png_malloc_default(png_ptr, size));
 441    if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
 442        png_error(png_ptr, "Out of Memory!");
 443    return (ret);
 444 }
 445
 446 png_voidp PNGAPI
 447 png_malloc_default(png_structp png_ptr, png_uint_32 size)
 448 {
 449    png_voidp ret;
 450 #endif /* PNG_USER_MEM_SUPPORTED */
 451
 452    if (png_ptr == NULL || size == 0)
 453       return (NULL);
 454
 455 #ifdef PNG_MAX_MALLOC_64K
 456    if (size > (png_uint_32)65536L)
 457    {
 458 #ifndef PNG_USER_MEM_SUPPORTED
 459       if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
 460          png_error(png_ptr, "Cannot Allocate > 64K");
 461       else
 462 #endif
 463          return NULL;
 464    }
 465 #endif
 466
 467  /* Check for overflow */
 468 #if defined(__TURBOC__) && !defined(__FLAT__)
 469  if (size != (unsigned long)size)
 470    ret = NULL;
 471  else
 472    ret = farmalloc(size);
 473 #else
 474 # if defined(_MSC_VER) && defined(MAXSEG_64K)
 475  if (size != (unsigned long)size)
 476    ret = NULL;
 477  else
 478    ret = halloc(size, 1);
 479 # else
 480  if (size != (size_t)size)
 481    ret = NULL;
 482  else
 483    ret = malloc((size_t)size);
 484 # endif
 485 #endif
 486
 487 #ifndef PNG_USER_MEM_SUPPORTED
 488    if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
 489       png_error(png_ptr, "Out of Memory");
 490 #endif
 491
 492    return (ret);
 493 }
 494
 495 /* Free a pointer allocated by png_malloc().  If ptr is NULL, return
 496    without taking any action. */
 497 void PNGAPI
 498 png_free(png_structp png_ptr, png_voidp ptr)
 499 {
 500    if (png_ptr == NULL || ptr == NULL)
 501       return;
 502
 503 #ifdef PNG_USER_MEM_SUPPORTED
 504    if (png_ptr->free_fn != NULL)
 505    {
 506       (*(png_ptr->free_fn))(png_ptr, ptr);
 507       return;
 508    }
 509    else png_free_default(png_ptr, ptr);
 510 }
 511 void PNGAPI
 512 png_free_default(png_structp png_ptr, png_voidp ptr)
 513 {
 514    if (png_ptr == NULL || ptr == NULL)
 515       return;
 516
 517 #endif /* PNG_USER_MEM_SUPPORTED */
 518
 519 #if defined(__TURBOC__) && !defined(__FLAT__)
 520    farfree(ptr);
 521 #else
 522 # if defined(_MSC_VER) && defined(MAXSEG_64K)
 523    hfree(ptr);
 524 # else
 525    free(ptr);
 526 # endif
 527 #endif
 528 }
 529
 530 #endif /* Not Borland DOS special memory handler */
 531
 532 #if defined(PNG_1_0_X)
 533 #  define png_malloc_warn png_malloc
 534 #else
 535 /* This function was added at libpng version 1.2.3.  The png_malloc_warn()
 536  * function will set up png_malloc() to issue a png_warning and return NULL
 537  * instead of issuing a png_error, if it fails to allocate the requested
 538  * memory.
 539  */
 540 png_voidp PNGAPI
 541 png_malloc_warn(png_structp png_ptr, png_uint_32 size)
 542 {
 543    png_voidp ptr;
 544    png_uint_32 save_flags;
 545    if (png_ptr == NULL) return (NULL);
 546
 547    save_flags = png_ptr->flags;
 548    png_ptr->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
 549    ptr = (png_voidp)png_malloc((png_structp)png_ptr, size);
 550    png_ptr->flags=save_flags;
 551    return(ptr);
 552 }
 553 #endif
 554
 555 png_voidp PNGAPI
 556 png_memcpy_check (png_structp png_ptr, png_voidp s1, png_voidp s2,
 557    png_uint_32 length)
 558 {
 559    png_size_t size;
 560
 561    size = (png_size_t)length;
 562    if ((png_uint_32)size != length)
 563       png_error(png_ptr, "Overflow in png_memcpy_check.");
 564
 565    return(png_memcpy (s1, s2, size));
 566 }
 567
 568 png_voidp PNGAPI
 569 png_memset_check (png_structp png_ptr, png_voidp s1, int value,
 570    png_uint_32 length)
 571 {
 572    png_size_t size;
 573
 574    size = (png_size_t)length;
 575    if ((png_uint_32)size != length)
 576       png_error(png_ptr, "Overflow in png_memset_check.");
 577
 578    return (png_memset (s1, value, size));
 579
 580 }
 581
 582 #ifdef PNG_USER_MEM_SUPPORTED
 583 /* This function is called when the application wants to use another method
 584  * of allocating and freeing memory.
 585  */
 586 void PNGAPI
 587 png_set_mem_fn(png_structp png_ptr, png_voidp mem_ptr, png_malloc_ptr
 588   malloc_fn, png_free_ptr free_fn)
 589 {
 590    if (png_ptr != NULL)
 591    {
 592       png_ptr->mem_ptr = mem_ptr;
 593       png_ptr->malloc_fn = malloc_fn;
 594       png_ptr->free_fn = free_fn;
 595    }
 596 }
 597
 598 /* This function returns a pointer to the mem_ptr associated with the user
 599  * functions.  The application should free any memory associated with this
 600  * pointer before png_write_destroy and png_read_destroy are called.
 601  */
 602 png_voidp PNGAPI
 603 png_get_mem_ptr(png_structp png_ptr)
 604 {
 605    if (png_ptr == NULL) return (NULL);
 606    return ((png_voidp)png_ptr->mem_ptr);
 607 }
 608 #endif /* PNG_USER_MEM_SUPPORTED */
 609 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */