core/libs/libpng-1.2.18/png.c

   1
   2 /* png.c - location for general purpose libpng functions
   3  *
   4  * Last changed in libpng 1.2.17 May 15, 2007
   5  * For conditions of distribution and use, see copyright notice in png.h
   6  * Copyright (c) 1998-2007 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
  11 #define PNG_INTERNAL
  12 #define PNG_NO_EXTERN
  13 #include "png.h"
  14
  15 /* Generate a compiler error if there is an old png.h in the search path. */
  16 typedef version_1_2_18 Your_png_h_is_not_version_1_2_18;
  17
  18 /* Version information for C files.  This had better match the version
  19  * string defined in png.h.  */
  20
  21 #ifdef PNG_USE_GLOBAL_ARRAYS
  22 /* png_libpng_ver was changed to a function in version 1.0.5c */
  23 const char png_libpng_ver[18] = PNG_LIBPNG_VER_STRING;
  24
  25 #ifdef PNG_READ_SUPPORTED
  26
  27 /* png_sig was changed to a function in version 1.0.5c */
  28 /* Place to hold the signature string for a PNG file. */
  29 const png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
  30 #endif /* PNG_READ_SUPPORTED */
  31
  32 /* Invoke global declarations for constant strings for known chunk types */
  33 PNG_IHDR;
  34 PNG_IDAT;
  35 PNG_IEND;
  36 PNG_PLTE;
  37 PNG_bKGD;
  38 PNG_cHRM;
  39 PNG_gAMA;
  40 PNG_hIST;
  41 PNG_iCCP;
  42 PNG_iTXt;
  43 PNG_oFFs;
  44 PNG_pCAL;
  45 PNG_sCAL;
  46 PNG_pHYs;
  47 PNG_sBIT;
  48 PNG_sPLT;
  49 PNG_sRGB;
  50 PNG_tEXt;
  51 PNG_tIME;
  52 PNG_tRNS;
  53 PNG_zTXt;
  54
  55 #ifdef PNG_READ_SUPPORTED
  56 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
  57
  58 /* start of interlace block */
  59 const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
  60
  61 /* offset to next interlace block */
  62 const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
  63
  64 /* start of interlace block in the y direction */
  65 const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
  66
  67 /* offset to next interlace block in the y direction */
  68 const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
  69
  70 /* width of interlace block (used in assembler routines only) */
  71 #ifdef PNG_HAVE_MMX_COMBINE_ROW
  72 const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
  73 #endif
  74
  75 /* Height of interlace block.  This is not currently used - if you need
  76  * it, uncomment it here and in png.h
  77 const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
  78 */
  79
  80 /* Mask to determine which pixels are valid in a pass */
  81 const int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
  82
  83 /* Mask to determine which pixels to overwrite while displaying */
  84 const int FARDATA png_pass_dsp_mask[]
  85    = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
  86
  87 #endif /* PNG_READ_SUPPORTED */
  88 #endif /* PNG_USE_GLOBAL_ARRAYS */
  89
  90 /* Tells libpng that we have already handled the first "num_bytes" bytes
  91  * of the PNG file signature.  If the PNG data is embedded into another
  92  * stream we can set num_bytes = 8 so that libpng will not attempt to read
  93  * or write any of the magic bytes before it starts on the IHDR.
  94  */
  95
  96 #ifdef PNG_READ_SUPPORTED
  97 void PNGAPI
  98 png_set_sig_bytes(png_structp png_ptr, int num_bytes)
  99 {
 100    if(png_ptr == NULL) return;
 101    png_debug(1, "in png_set_sig_bytes\n");
 102    if (num_bytes > 8)
 103       png_error(png_ptr, "Too many bytes for PNG signature.");
 104
 105    png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
 106 }
 107
 108 /* Checks whether the supplied bytes match the PNG signature.  We allow
 109  * checking less than the full 8-byte signature so that those apps that
 110  * already read the first few bytes of a file to determine the file type
 111  * can simply check the remaining bytes for extra assurance.  Returns
 112  * an integer less than, equal to, or greater than zero if sig is found,
 113  * respectively, to be less than, to match, or be greater than the correct
 114  * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
 115  */
 116 int PNGAPI
 117 png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
 118 {
 119    png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
 120    if (num_to_check > 8)
 121       num_to_check = 8;
 122    else if (num_to_check < 1)
 123       return (-1);
 124
 125    if (start > 7)
 126       return (-1);
 127
 128    if (start + num_to_check > 8)
 129       num_to_check = 8 - start;
 130
 131    return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
 132 }
 133
 134 #if defined(PNG_1_0_X) || defined(PNG_1_2_X)
 135 /* (Obsolete) function to check signature bytes.  It does not allow one
 136  * to check a partial signature.  This function might be removed in the
 137  * future - use png_sig_cmp().  Returns true (nonzero) if the file is a PNG.
 138  */
 139 int PNGAPI
 140 png_check_sig(png_bytep sig, int num)
 141 {
 142   return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
 143 }
 144 #endif
 145 #endif /* PNG_READ_SUPPORTED */
 146
 147 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
 148 /* Function to allocate memory for zlib and clear it to 0. */
 149 #ifdef PNG_1_0_X
 150 voidpf PNGAPI
 151 #else
 152 voidpf /* private */
 153 #endif
 154 png_zalloc(voidpf png_ptr, uInt items, uInt size)
 155 {
 156    png_voidp ptr;
 157    png_structp p=(png_structp)png_ptr;
 158    png_uint_32 save_flags=p->flags;
 159    png_uint_32 num_bytes;
 160
 161    if(png_ptr == NULL) return (NULL);
 162    if (items > PNG_UINT_32_MAX/size)
 163    {
 164      png_warning (p, "Potential overflow in png_zalloc()");
 165      return (NULL);
 166    }
 167    num_bytes = (png_uint_32)items * size;
 168
 169    p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
 170    ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
 171    p->flags=save_flags;
 172
 173 #if defined(PNG_1_0_X) && !defined(PNG_NO_ZALLOC_ZERO)
 174    if (ptr == NULL)
 175        return ((voidpf)ptr);
 176
 177    if (num_bytes > (png_uint_32)0x8000L)
 178    {
 179       png_memset(ptr, 0, (png_size_t)0x8000L);
 180       png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
 181          (png_size_t)(num_bytes - (png_uint_32)0x8000L));
 182    }
 183    else
 184    {
 185       png_memset(ptr, 0, (png_size_t)num_bytes);
 186    }
 187 #endif
 188    return ((voidpf)ptr);
 189 }
 190
 191 /* function to free memory for zlib */
 192 #ifdef PNG_1_0_X
 193 void PNGAPI
 194 #else
 195 void /* private */
 196 #endif
 197 png_zfree(voidpf png_ptr, voidpf ptr)
 198 {
 199    png_free((png_structp)png_ptr, (png_voidp)ptr);
 200 }
 201
 202 /* Reset the CRC variable to 32 bits of 1's.  Care must be taken
 203  * in case CRC is > 32 bits to leave the top bits 0.
 204  */
 205 void /* PRIVATE */
 206 png_reset_crc(png_structp png_ptr)
 207 {
 208    png_ptr->crc = crc32(0, Z_NULL, 0);
 209 }
 210
 211 /* Calculate the CRC over a section of data.  We can only pass as
 212  * much data to this routine as the largest single buffer size.  We
 213  * also check that this data will actually be used before going to the
 214  * trouble of calculating it.
 215  */
 216 void /* PRIVATE */
 217 png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
 218 {
 219    int need_crc = 1;
 220
 221    if (png_ptr->chunk_name[0] & 0x20)                     /* ancillary */
 222    {
 223       if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
 224           (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
 225          need_crc = 0;
 226    }
 227    else                                                    /* critical */
 228    {
 229       if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
 230          need_crc = 0;
 231    }
 232
 233    if (need_crc)
 234       png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
 235 }
 236
 237 /* Allocate the memory for an info_struct for the application.  We don't
 238  * really need the png_ptr, but it could potentially be useful in the
 239  * future.  This should be used in favour of malloc(png_sizeof(png_info))
 240  * and png_info_init() so that applications that want to use a shared
 241  * libpng don't have to be recompiled if png_info changes size.
 242  */
 243 png_infop PNGAPI
 244 png_create_info_struct(png_structp png_ptr)
 245 {
 246    png_infop info_ptr;
 247
 248    png_debug(1, "in png_create_info_struct\n");
 249    if(png_ptr == NULL) return (NULL);
 250 #ifdef PNG_USER_MEM_SUPPORTED
 251    info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
 252       png_ptr->malloc_fn, png_ptr->mem_ptr);
 253 #else
 254    info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
 255 #endif
 256    if (info_ptr != NULL)
 257       png_info_init_3(&info_ptr, png_sizeof(png_info));
 258
 259    return (info_ptr);
 260 }
 261
 262 /* This function frees the memory associated with a single info struct.
 263  * Normally, one would use either png_destroy_read_struct() or
 264  * png_destroy_write_struct() to free an info struct, but this may be
 265  * useful for some applications.
 266  */
 267 void PNGAPI
 268 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
 269 {
 270    png_infop info_ptr = NULL;
 271    if(png_ptr == NULL) return;
 272
 273    png_debug(1, "in png_destroy_info_struct\n");
 274    if (info_ptr_ptr != NULL)
 275       info_ptr = *info_ptr_ptr;
 276
 277    if (info_ptr != NULL)
 278    {
 279       png_info_destroy(png_ptr, info_ptr);
 280
 281 #ifdef PNG_USER_MEM_SUPPORTED
 282       png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
 283           png_ptr->mem_ptr);
 284 #else
 285       png_destroy_struct((png_voidp)info_ptr);
 286 #endif
 287       *info_ptr_ptr = NULL;
 288    }
 289 }
 290
 291 /* Initialize the info structure.  This is now an internal function (0.89)
 292  * and applications using it are urged to use png_create_info_struct()
 293  * instead.
 294  */
 295 #if defined(PNG_1_0_X) || defined(PNG_1_2_X)
 296 #undef png_info_init
 297 void PNGAPI
 298 png_info_init(png_infop info_ptr)
 299 {
 300    /* We only come here via pre-1.0.12-compiled applications */
 301    png_info_init_3(&info_ptr, 0);
 302 }
 303 #endif
 304
 305 void PNGAPI
 306 png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
 307 {
 308    png_infop info_ptr = *ptr_ptr;
 309
 310    if(info_ptr == NULL) return;
 311
 312    png_debug(1, "in png_info_init_3\n");
 313
 314    if(png_sizeof(png_info) > png_info_struct_size)
 315      {
 316        png_destroy_struct(info_ptr);
 317        info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
 318        *ptr_ptr = info_ptr;
 319      }
 320
 321    /* set everything to 0 */
 322    png_memset(info_ptr, 0, png_sizeof (png_info));
 323 }
 324
 325 #ifdef PNG_FREE_ME_SUPPORTED
 326 void PNGAPI
 327 png_data_freer(png_structp png_ptr, png_infop info_ptr,
 328    int freer, png_uint_32 mask)
 329 {
 330    png_debug(1, "in png_data_freer\n");
 331    if (png_ptr == NULL || info_ptr == NULL)
 332       return;
 333    if(freer == PNG_DESTROY_WILL_FREE_DATA)
 334       info_ptr->free_me |= mask;
 335    else if(freer == PNG_USER_WILL_FREE_DATA)
 336       info_ptr->free_me &= ~mask;
 337    else
 338       png_warning(png_ptr,
 339          "Unknown freer parameter in png_data_freer.");
 340 }
 341 #endif
 342
 343 void PNGAPI
 344 png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
 345    int num)
 346 {
 347    png_debug(1, "in png_free_data\n");
 348    if (png_ptr == NULL || info_ptr == NULL)
 349       return;
 350
 351 #if defined(PNG_TEXT_SUPPORTED)
 352 /* free text item num or (if num == -1) all text items */
 353 #ifdef PNG_FREE_ME_SUPPORTED
 354 if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
 355 #else
 356 if (mask & PNG_FREE_TEXT)
 357 #endif
 358 {
 359    if (num != -1)
 360    {
 361      if (info_ptr->text && info_ptr->text[num].key)
 362      {
 363          png_free(png_ptr, info_ptr->text[num].key);
 364          info_ptr->text[num].key = NULL;
 365      }
 366    }
 367    else
 368    {
 369        int i;
 370        for (i = 0; i < info_ptr->num_text; i++)
 371            png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
 372        png_free(png_ptr, info_ptr->text);
 373        info_ptr->text = NULL;
 374        info_ptr->num_text=0;
 375    }
 376 }
 377 #endif
 378
 379 #if defined(PNG_tRNS_SUPPORTED)
 380 /* free any tRNS entry */
 381 #ifdef PNG_FREE_ME_SUPPORTED
 382 if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
 383 #else
 384 if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
 385 #endif
 386 {
 387     png_free(png_ptr, info_ptr->trans);
 388     info_ptr->valid &= ~PNG_INFO_tRNS;
 389 #ifndef PNG_FREE_ME_SUPPORTED
 390     png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
 391 #endif
 392     info_ptr->trans = NULL;
 393 }
 394 #endif
 395
 396 #if defined(PNG_sCAL_SUPPORTED)
 397 /* free any sCAL entry */
 398 #ifdef PNG_FREE_ME_SUPPORTED
 399 if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
 400 #else
 401 if (mask & PNG_FREE_SCAL)
 402 #endif
 403 {
 404 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
 405     png_free(png_ptr, info_ptr->scal_s_width);
 406     png_free(png_ptr, info_ptr->scal_s_height);
 407     info_ptr->scal_s_width = NULL;
 408     info_ptr->scal_s_height = NULL;
 409 #endif
 410     info_ptr->valid &= ~PNG_INFO_sCAL;
 411 }
 412 #endif
 413
 414 #if defined(PNG_pCAL_SUPPORTED)
 415 /* free any pCAL entry */
 416 #ifdef PNG_FREE_ME_SUPPORTED
 417 if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
 418 #else
 419 if (mask & PNG_FREE_PCAL)
 420 #endif
 421 {
 422     png_free(png_ptr, info_ptr->pcal_purpose);
 423     png_free(png_ptr, info_ptr->pcal_units);
 424     info_ptr->pcal_purpose = NULL;
 425     info_ptr->pcal_units = NULL;
 426     if (info_ptr->pcal_params != NULL)
 427     {
 428         int i;
 429         for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
 430         {
 431           png_free(png_ptr, info_ptr->pcal_params[i]);
 432           info_ptr->pcal_params[i]=NULL;
 433         }
 434         png_free(png_ptr, info_ptr->pcal_params);
 435         info_ptr->pcal_params = NULL;
 436     }
 437     info_ptr->valid &= ~PNG_INFO_pCAL;
 438 }
 439 #endif
 440
 441 #if defined(PNG_iCCP_SUPPORTED)
 442 /* free any iCCP entry */
 443 #ifdef PNG_FREE_ME_SUPPORTED
 444 if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
 445 #else
 446 if (mask & PNG_FREE_ICCP)
 447 #endif
 448 {
 449     png_free(png_ptr, info_ptr->iccp_name);
 450     png_free(png_ptr, info_ptr->iccp_profile);
 451     info_ptr->iccp_name = NULL;
 452     info_ptr->iccp_profile = NULL;
 453     info_ptr->valid &= ~PNG_INFO_iCCP;
 454 }
 455 #endif
 456
 457 #if defined(PNG_sPLT_SUPPORTED)
 458 /* free a given sPLT entry, or (if num == -1) all sPLT entries */
 459 #ifdef PNG_FREE_ME_SUPPORTED
 460 if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
 461 #else
 462 if (mask & PNG_FREE_SPLT)
 463 #endif
 464 {
 465    if (num != -1)
 466    {
 467       if(info_ptr->splt_palettes)
 468       {
 469           png_free(png_ptr, info_ptr->splt_palettes[num].name);
 470           png_free(png_ptr, info_ptr->splt_palettes[num].entries);
 471           info_ptr->splt_palettes[num].name = NULL;
 472           info_ptr->splt_palettes[num].entries = NULL;
 473       }
 474    }
 475    else
 476    {
 477        if(info_ptr->splt_palettes_num)
 478        {
 479          int i;
 480          for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
 481             png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
 482
 483          png_free(png_ptr, info_ptr->splt_palettes);
 484          info_ptr->splt_palettes = NULL;
 485          info_ptr->splt_palettes_num = 0;
 486        }
 487        info_ptr->valid &= ~PNG_INFO_sPLT;
 488    }
 489 }
 490 #endif
 491
 492 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
 493   if(png_ptr->unknown_chunk.data)
 494   {
 495     png_free(png_ptr, png_ptr->unknown_chunk.data);
 496     png_ptr->unknown_chunk.data = NULL;
 497   }
 498 #ifdef PNG_FREE_ME_SUPPORTED
 499 if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
 500 #else
 501 if (mask & PNG_FREE_UNKN)
 502 #endif
 503 {
 504    if (num != -1)
 505    {
 506        if(info_ptr->unknown_chunks)
 507        {
 508           png_free(png_ptr, info_ptr->unknown_chunks[num].data);
 509           info_ptr->unknown_chunks[num].data = NULL;
 510        }
 511    }
 512    else
 513    {
 514        int i;
 515
 516        if(info_ptr->unknown_chunks_num)
 517        {
 518          for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
 519             png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
 520
 521          png_free(png_ptr, info_ptr->unknown_chunks);
 522          info_ptr->unknown_chunks = NULL;
 523          info_ptr->unknown_chunks_num = 0;
 524        }
 525    }
 526 }
 527 #endif
 528
 529 #if defined(PNG_hIST_SUPPORTED)
 530 /* free any hIST entry */
 531 #ifdef PNG_FREE_ME_SUPPORTED
 532 if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
 533 #else
 534 if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
 535 #endif
 536 {
 537     png_free(png_ptr, info_ptr->hist);
 538     info_ptr->hist = NULL;
 539     info_ptr->valid &= ~PNG_INFO_hIST;
 540 #ifndef PNG_FREE_ME_SUPPORTED
 541     png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
 542 #endif
 543 }
 544 #endif
 545
 546 /* free any PLTE entry that was internally allocated */
 547 #ifdef PNG_FREE_ME_SUPPORTED
 548 if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
 549 #else
 550 if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
 551 #endif
 552 {
 553     png_zfree(png_ptr, info_ptr->palette);
 554     info_ptr->palette = NULL;
 555     info_ptr->valid &= ~PNG_INFO_PLTE;
 556 #ifndef PNG_FREE_ME_SUPPORTED
 557     png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
 558 #endif
 559     info_ptr->num_palette = 0;
 560 }
 561
 562 #if defined(PNG_INFO_IMAGE_SUPPORTED)
 563 /* free any image bits attached to the info structure */
 564 #ifdef PNG_FREE_ME_SUPPORTED
 565 if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
 566 #else
 567 if (mask & PNG_FREE_ROWS)
 568 #endif
 569 {
 570     if(info_ptr->row_pointers)
 571     {
 572        int row;
 573        for (row = 0; row < (int)info_ptr->height; row++)
 574        {
 575           png_free(png_ptr, info_ptr->row_pointers[row]);
 576           info_ptr->row_pointers[row]=NULL;
 577        }
 578        png_free(png_ptr, info_ptr->row_pointers);
 579        info_ptr->row_pointers=NULL;
 580     }
 581     info_ptr->valid &= ~PNG_INFO_IDAT;
 582 }
 583 #endif
 584
 585 #ifdef PNG_FREE_ME_SUPPORTED
 586    if(num == -1)
 587      info_ptr->free_me &= ~mask;
 588    else
 589      info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
 590 #endif
 591 }
 592
 593 /* This is an internal routine to free any memory that the info struct is
 594  * pointing to before re-using it or freeing the struct itself.  Recall
 595  * that png_free() checks for NULL pointers for us.
 596  */
 597 void /* PRIVATE */
 598 png_info_destroy(png_structp png_ptr, png_infop info_ptr)
 599 {
 600    png_debug(1, "in png_info_destroy\n");
 601
 602    png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
 603
 604 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
 605    if (png_ptr->num_chunk_list)
 606    {
 607        png_free(png_ptr, png_ptr->chunk_list);
 608        png_ptr->chunk_list=NULL;
 609        png_ptr->num_chunk_list=0;
 610    }
 611 #endif
 612
 613    png_info_init_3(&info_ptr, png_sizeof(png_info));
 614 }
 615 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
 616
 617 /* This function returns a pointer to the io_ptr associated with the user
 618  * functions.  The application should free any memory associated with this
 619  * pointer before png_write_destroy() or png_read_destroy() are called.
 620  */
 621 png_voidp PNGAPI
 622 png_get_io_ptr(png_structp png_ptr)
 623 {
 624    if(png_ptr == NULL) return (NULL);
 625    return (png_ptr->io_ptr);
 626 }
 627
 628 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
 629 #if !defined(PNG_NO_STDIO)
 630 /* Initialize the default input/output functions for the PNG file.  If you
 631  * use your own read or write routines, you can call either png_set_read_fn()
 632  * or png_set_write_fn() instead of png_init_io().  If you have defined
 633  * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
 634  * necessarily available.
 635  */
 636 void PNGAPI
 637 png_init_io(png_structp png_ptr, png_FILE_p fp)
 638 {
 639    png_debug(1, "in png_init_io\n");
 640    if(png_ptr == NULL) return;
 641    png_ptr->io_ptr = (png_voidp)fp;
 642 }
 643 #endif
 644
 645 #if defined(PNG_TIME_RFC1123_SUPPORTED)
 646 /* Convert the supplied time into an RFC 1123 string suitable for use in
 647  * a "Creation Time" or other text-based time string.
 648  */
 649 png_charp PNGAPI
 650 png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
 651 {
 652    static PNG_CONST char short_months[12][4] =
 653         {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
 654          "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
 655
 656    if(png_ptr == NULL) return (NULL);
 657    if (png_ptr->time_buffer == NULL)
 658    {
 659       png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
 660          png_sizeof(char)));
 661    }
 662
 663 #if defined(_WIN32_WCE)
 664    {
 665       wchar_t time_buf[29];
 666       wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
 667           ptime->day % 32, short_months[(ptime->month - 1) % 12],
 668         ptime->year, ptime->hour % 24, ptime->minute % 60,
 669           ptime->second % 61);
 670       WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
 671           NULL, NULL);
 672    }
 673 #else
 674 #ifdef USE_FAR_KEYWORD
 675    {
 676       char near_time_buf[29];
 677       sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
 678           ptime->day % 32, short_months[(ptime->month - 1) % 12],
 679           ptime->year, ptime->hour % 24, ptime->minute % 60,
 680           ptime->second % 61);
 681       png_memcpy(png_ptr->time_buffer, near_time_buf,
 682           29*png_sizeof(char));
 683    }
 684 #else
 685    sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
 686        ptime->day % 32, short_months[(ptime->month - 1) % 12],
 687        ptime->year, ptime->hour % 24, ptime->minute % 60,
 688        ptime->second % 61);
 689 #endif
 690 #endif /* _WIN32_WCE */
 691    return ((png_charp)png_ptr->time_buffer);
 692 }
 693 #endif /* PNG_TIME_RFC1123_SUPPORTED */
 694
 695 #if 0
 696 /* Signature string for a PNG file. */
 697 png_bytep PNGAPI
 698 png_sig_bytes(void)
 699 {
 700    return ((png_bytep)"\211\120\116\107\015\012\032\012");
 701 }
 702 #endif
 703 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
 704
 705 png_charp PNGAPI
 706 png_get_copyright(png_structp png_ptr)
 707 {
 708    if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
 709    return ((png_charp) "\n libpng version 1.2.18 - May 15, 2007\n\
 710    Copyright (c) 1998-2007 Glenn Randers-Pehrson\n\
 711    Copyright (c) 1996-1997 Andreas Dilger\n\
 712    Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
 713    return ((png_charp) "");
 714 }
 715
 716 /* The following return the library version as a short string in the
 717  * format 1.0.0 through 99.99.99zz.  To get the version of *.h files
 718  * used with your application, print out PNG_LIBPNG_VER_STRING, which
 719  * is defined in png.h.
 720  * Note: now there is no difference between png_get_libpng_ver() and
 721  * png_get_header_ver().  Due to the version_nn_nn_nn typedef guard,
 722  * it is guaranteed that png.c uses the correct version of png.h.
 723  */
 724 png_charp PNGAPI
 725 png_get_libpng_ver(png_structp png_ptr)
 726 {
 727    /* Version of *.c files used when building libpng */
 728    if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
 729       return ((png_charp) PNG_LIBPNG_VER_STRING);
 730    return ((png_charp) "");
 731 }
 732
 733 png_charp PNGAPI
 734 png_get_header_ver(png_structp png_ptr)
 735 {
 736    /* Version of *.h files used when building libpng */
 737    if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
 738       return ((png_charp) PNG_LIBPNG_VER_STRING);
 739    return ((png_charp) "");
 740 }
 741
 742 png_charp PNGAPI
 743 png_get_header_version(png_structp png_ptr)
 744 {
 745    /* Returns longer string containing both version and date */
 746    if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
 747       return ((png_charp) PNG_HEADER_VERSION_STRING);
 748    return ((png_charp) "");
 749 }
 750
 751 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
 752 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 753 int PNGAPI
 754 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
 755 {
 756    /* check chunk_name and return "keep" value if it's on the list, else 0 */
 757    int i;
 758    png_bytep p;
 759    if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
 760       return 0;
 761    p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
 762    for (i = png_ptr->num_chunk_list; i; i--, p-=5)
 763       if (!png_memcmp(chunk_name, p, 4))
 764         return ((int)*(p+4));
 765    return 0;
 766 }
 767 #endif
 768
 769 /* This function, added to libpng-1.0.6g, is untested. */
 770 int PNGAPI
 771 png_reset_zstream(png_structp png_ptr)
 772 {
 773    if (png_ptr == NULL) return Z_STREAM_ERROR;
 774    return (inflateReset(&png_ptr->zstream));
 775 }
 776 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
 777
 778 /* This function was added to libpng-1.0.7 */
 779 png_uint_32 PNGAPI
 780 png_access_version_number(void)
 781 {
 782    /* Version of *.c files used when building libpng */
 783    return((png_uint_32) PNG_LIBPNG_VER);
 784 }
 785
 786
 787 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ASSEMBLER_CODE_SUPPORTED)
 788 #if !defined(PNG_1_0_X)
 789 #if defined(PNG_MMX_CODE_SUPPORTED)
 790 /* this INTERNAL function was added to libpng 1.2.0 */
 791 void /* PRIVATE */
 792 png_init_mmx_flags (png_structp png_ptr)
 793 {
 794     if(png_ptr == NULL) return;
 795     png_ptr->mmx_rowbytes_threshold = 0;
 796     png_ptr->mmx_bitdepth_threshold = 0;
 797
 798 #  if (defined(PNG_USE_PNGVCRD) || defined(PNG_USE_PNGGCCRD))
 799
 800     png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_COMPILED;
 801
 802     if (png_mmx_support() > 0) {
 803         png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
 804 #    ifdef PNG_HAVE_MMX_COMBINE_ROW
 805                               | PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
 806 #    endif
 807 #    ifdef PNG_HAVE_MMX_READ_INTERLACE
 808                               | PNG_ASM_FLAG_MMX_READ_INTERLACE
 809 #    endif
 810 #    ifndef PNG_HAVE_MMX_READ_FILTER_ROW
 811                               ;
 812 #    else
 813                               | PNG_ASM_FLAG_MMX_READ_FILTER_SUB
 814                               | PNG_ASM_FLAG_MMX_READ_FILTER_UP
 815                               | PNG_ASM_FLAG_MMX_READ_FILTER_AVG
 816                               | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
 817
 818         png_ptr->mmx_rowbytes_threshold = PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT;
 819         png_ptr->mmx_bitdepth_threshold = PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT;
 820 #    endif
 821     } else {
 822         png_ptr->asm_flags &= ~( PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
 823                                | PNG_MMX_READ_FLAGS
 824                                | PNG_MMX_WRITE_FLAGS );
 825     }
 826
 827 #  else /* !(PNGVCRD || PNGGCCRD) */
 828
 829     /* clear all MMX flags; no support is compiled in */
 830     png_ptr->asm_flags &= ~( PNG_MMX_FLAGS );
 831
 832 #  endif /* ?(PNGVCRD || PNGGCCRD) */
 833 }
 834
 835 #endif /* !(PNG_MMX_CODE_SUPPORTED) */
 836
 837 /* this function was added to libpng 1.2.0 */
 838 #if !defined(PNG_USE_PNGGCCRD) && \
 839     !(defined(PNG_MMX_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
 840 int PNGAPI
 841 png_mmx_support(void)
 842 {
 843     return -1;
 844 }
 845 #endif
 846 #endif /* PNG_1_0_X  && PNG_ASSEMBLER_CODE_SUPPORTED */
 847 #endif /* PNG_READ_SUPPORTED */
 848
 849 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
 850 #ifdef PNG_SIZE_T
 851 /* Added at libpng version 1.2.6 */
 852    PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));
 853 png_size_t PNGAPI
 854 png_convert_size(size_t size)
 855 {
 856   if (size > (png_size_t)-1)
 857      PNG_ABORT();  /* We haven't got access to png_ptr, so no png_error() */
 858   return ((png_size_t)size);
 859 }
 860 #endif /* PNG_SIZE_T */
 861 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */