src/png/png.c

   1
   2 /* png.c - location for general purpose libpng functions
   3  *
   4  * libpng version 1.2.4 - July 8, 2002
   5  * Copyright (c) 1998-2002 Glenn Randers-Pehrson
   6  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
   7  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
   8  *
   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_4 Your_png_h_is_not_version_1_2_4;
  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] = "1.2.4";
  24
  25 /* png_sig was changed to a function in version 1.0.5c */
  26 /* Place to hold the signature string for a PNG file. */
  27 const png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
  28
  29 /* Invoke global declarations for constant strings for known chunk types */
  30 PNG_IHDR;
  31 PNG_IDAT;
  32 PNG_IEND;
  33 PNG_PLTE;
  34 PNG_bKGD;
  35 PNG_cHRM;
  36 PNG_gAMA;
  37 PNG_hIST;
  38 PNG_iCCP;
  39 PNG_iTXt;
  40 PNG_oFFs;
  41 PNG_pCAL;
  42 PNG_sCAL;
  43 PNG_pHYs;
  44 PNG_sBIT;
  45 PNG_sPLT;
  46 PNG_sRGB;
  47 PNG_tEXt;
  48 PNG_tIME;
  49 PNG_tRNS;
  50 PNG_zTXt;
  51
  52 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
  53
  54 /* start of interlace block */
  55 const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
  56
  57 /* offset to next interlace block */
  58 const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
  59
  60 /* start of interlace block in the y direction */
  61 const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
  62
  63 /* offset to next interlace block in the y direction */
  64 const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
  65
  66 /* width of interlace block (used in assembler routines only) */
  67 #ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
  68 const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
  69 #endif
  70
  71 /* Height of interlace block.  This is not currently used - if you need
  72  * it, uncomment it here and in png.h
  73 const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
  74 */
  75
  76 /* Mask to determine which pixels are valid in a pass */
  77 const int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
  78
  79 /* Mask to determine which pixels to overwrite while displaying */
  80 const int FARDATA png_pass_dsp_mask[]
  81    = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
  82
  83 #endif
  84
  85 /* Tells libpng that we have already handled the first "num_bytes" bytes
  86  * of the PNG file signature.  If the PNG data is embedded into another
  87  * stream we can set num_bytes = 8 so that libpng will not attempt to read
  88  * or write any of the magic bytes before it starts on the IHDR.
  89  */
  90
  91 void PNGAPI
  92 png_set_sig_bytes(png_structp png_ptr, int num_bytes)
  93 {
  94    png_debug(1, "in png_set_sig_bytes\n");
  95    if (num_bytes > 8)
  96       png_error(png_ptr, "Too many bytes for PNG signature.");
  97
  98    png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
  99 }
 100
 101 /* Checks whether the supplied bytes match the PNG signature.  We allow
 102  * checking less than the full 8-byte signature so that those apps that
 103  * already read the first few bytes of a file to determine the file type
 104  * can simply check the remaining bytes for extra assurance.  Returns
 105  * an integer less than, equal to, or greater than zero if sig is found,
 106  * respectively, to be less than, to match, or be greater than the correct
 107  * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
 108  */
 109 int PNGAPI
 110 png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
 111 {
 112    png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
 113    if (num_to_check > 8)
 114       num_to_check = 8;
 115    else if (num_to_check < 1)
 116       return (0);
 117
 118    if (start > 7)
 119       return (0);
 120
 121    if (start + num_to_check > 8)
 122       num_to_check = 8 - start;
 123
 124    return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
 125 }
 126
 127 /* (Obsolete) function to check signature bytes.  It does not allow one
 128  * to check a partial signature.  This function might be removed in the
 129  * future - use png_sig_cmp().  Returns true (nonzero) if the file is a PNG.
 130  */
 131 int PNGAPI
 132 png_check_sig(png_bytep sig, int num)
 133 {
 134   return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
 135 }
 136
 137 /* Function to allocate memory for zlib and clear it to 0. */
 138 #ifdef PNG_1_0_X
 139 void PNGAPI
 140 #else
 141 voidpf /* private */
 142 #endif
 143 png_zalloc(voidpf png_ptr, uInt items, uInt size)
 144 {
 145    png_uint_32 num_bytes = (png_uint_32)items * size;
 146    png_voidp ptr;
 147    png_structp p=png_ptr;
 148    png_uint_32 save_flags=p->flags;
 149
 150    p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
 151    ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
 152    p->flags=save_flags;
 153
 154 #ifndef PNG_NO_ZALLOC_ZERO
 155    if (ptr == NULL)
 156        return ((voidpf)ptr);
 157
 158    if (num_bytes > (png_uint_32)0x8000L)
 159    {
 160       png_memset(ptr, 0, (png_size_t)0x8000L);
 161       png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
 162          (png_size_t)(num_bytes - (png_uint_32)0x8000L));
 163    }
 164    else
 165    {
 166       png_memset(ptr, 0, (png_size_t)num_bytes);
 167    }
 168 #endif
 169    return ((voidpf)ptr);
 170 }
 171
 172 /* function to free memory for zlib */
 173 #ifdef PNG_1_0_X
 174 void PNGAPI
 175 #else
 176 void /* private */
 177 #endif
 178 png_zfree(voidpf png_ptr, voidpf ptr)
 179 {
 180    png_free((png_structp)png_ptr, (png_voidp)ptr);
 181 }
 182
 183 /* Reset the CRC variable to 32 bits of 1's.  Care must be taken
 184  * in case CRC is > 32 bits to leave the top bits 0.
 185  */
 186 void /* PRIVATE */
 187 png_reset_crc(png_structp png_ptr)
 188 {
 189    png_ptr->crc = crc32(0, Z_NULL, 0);
 190 }
 191
 192 /* Calculate the CRC over a section of data.  We can only pass as
 193  * much data to this routine as the largest single buffer size.  We
 194  * also check that this data will actually be used before going to the
 195  * trouble of calculating it.
 196  */
 197 void /* PRIVATE */
 198 png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
 199 {
 200    int need_crc = 1;
 201
 202    if (png_ptr->chunk_name[0] & 0x20)                     /* ancillary */
 203    {
 204       if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
 205           (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
 206          need_crc = 0;
 207    }
 208    else                                                    /* critical */
 209    {
 210       if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
 211          need_crc = 0;
 212    }
 213
 214    if (need_crc)
 215       png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
 216 }
 217
 218 /* Allocate the memory for an info_struct for the application.  We don't
 219  * really need the png_ptr, but it could potentially be useful in the
 220  * future.  This should be used in favour of malloc(sizeof(png_info))
 221  * and png_info_init() so that applications that want to use a shared
 222  * libpng don't have to be recompiled if png_info changes size.
 223  */
 224 png_infop PNGAPI
 225 png_create_info_struct(png_structp png_ptr)
 226 {
 227    png_infop info_ptr;
 228
 229    png_debug(1, "in png_create_info_struct\n");
 230    if(png_ptr == NULL) return (NULL);
 231 #ifdef PNG_USER_MEM_SUPPORTED
 232    info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
 233       png_ptr->malloc_fn, png_ptr->mem_ptr);
 234 #else
 235    info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
 236 #endif
 237    if (info_ptr != NULL)
 238       png_info_init_3(&info_ptr, sizeof(png_info));
 239
 240    return (info_ptr);
 241 }
 242
 243 /* This function frees the memory associated with a single info struct.
 244  * Normally, one would use either png_destroy_read_struct() or
 245  * png_destroy_write_struct() to free an info struct, but this may be
 246  * useful for some applications.
 247  */
 248 void PNGAPI
 249 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
 250 {
 251    png_infop info_ptr = NULL;
 252
 253    png_debug(1, "in png_destroy_info_struct\n");
 254    if (info_ptr_ptr != NULL)
 255       info_ptr = *info_ptr_ptr;
 256
 257    if (info_ptr != NULL)
 258    {
 259       png_info_destroy(png_ptr, info_ptr);
 260
 261 #ifdef PNG_USER_MEM_SUPPORTED
 262       png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
 263           png_ptr->mem_ptr);
 264 #else
 265       png_destroy_struct((png_voidp)info_ptr);
 266 #endif
 267       *info_ptr_ptr = NULL;
 268    }
 269 }
 270
 271 /* Initialize the info structure.  This is now an internal function (0.89)
 272  * and applications using it are urged to use png_create_info_struct()
 273  * instead.
 274  */
 275 #undef png_info_init
 276 void PNGAPI
 277 png_info_init(png_infop info_ptr)
 278 {
 279    /* We only come here via pre-1.0.12-compiled applications */
 280    png_info_init_3(&info_ptr, 0);
 281 }
 282
 283 void PNGAPI
 284 png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
 285 {
 286    png_infop info_ptr = *ptr_ptr;
 287
 288    png_debug(1, "in png_info_init_3\n");
 289
 290    if(sizeof(png_info) > png_info_struct_size)
 291      {
 292        png_destroy_struct(info_ptr);
 293        info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
 294        *ptr_ptr = info_ptr;
 295      }
 296
 297    /* set everything to 0 */
 298    png_memset(info_ptr, 0, sizeof (png_info));
 299 }
 300
 301 #ifdef PNG_FREE_ME_SUPPORTED
 302 void PNGAPI
 303 png_data_freer(png_structp png_ptr, png_infop info_ptr,
 304    int freer, png_uint_32 mask)
 305 {
 306    png_debug(1, "in png_data_freer\n");
 307    if (png_ptr == NULL || info_ptr == NULL)
 308       return;
 309    if(freer == PNG_DESTROY_WILL_FREE_DATA)
 310       info_ptr->free_me |= mask;
 311    else if(freer == PNG_USER_WILL_FREE_DATA)
 312       info_ptr->free_me &= ~mask;
 313    else
 314       png_warning(png_ptr,
 315          "Unknown freer parameter in png_data_freer.");
 316 }
 317 #endif
 318
 319 void PNGAPI
 320 png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
 321    int num)
 322 {
 323    png_debug(1, "in png_free_data\n");
 324    if (png_ptr == NULL || info_ptr == NULL)
 325       return;
 326
 327 #if defined(PNG_TEXT_SUPPORTED)
 328 /* free text item num or (if num == -1) all text items */
 329 #ifdef PNG_FREE_ME_SUPPORTED
 330 if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
 331 #else
 332 if (mask & PNG_FREE_TEXT)
 333 #endif
 334 {
 335    if (num != -1)
 336    {
 337      if (info_ptr->text && info_ptr->text[num].key)
 338      {
 339          png_free(png_ptr, info_ptr->text[num].key);
 340          info_ptr->text[num].key = NULL;
 341      }
 342    }
 343    else
 344    {
 345        int i;
 346        for (i = 0; i < info_ptr->num_text; i++)
 347            png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
 348        png_free(png_ptr, info_ptr->text);
 349        info_ptr->text = NULL;
 350        info_ptr->num_text=0;
 351    }
 352 }
 353 #endif
 354
 355 #if defined(PNG_tRNS_SUPPORTED)
 356 /* free any tRNS entry */
 357 #ifdef PNG_FREE_ME_SUPPORTED
 358 if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
 359 #else
 360 if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
 361 #endif
 362 {
 363     png_free(png_ptr, info_ptr->trans);
 364     info_ptr->valid &= ~PNG_INFO_tRNS;
 365 #ifndef PNG_FREE_ME_SUPPORTED
 366     png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
 367 #endif
 368     info_ptr->trans = NULL;
 369 }
 370 #endif
 371
 372 #if defined(PNG_sCAL_SUPPORTED)
 373 /* free any sCAL entry */
 374 #ifdef PNG_FREE_ME_SUPPORTED
 375 if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
 376 #else
 377 if (mask & PNG_FREE_SCAL)
 378 #endif
 379 {
 380 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
 381     png_free(png_ptr, info_ptr->scal_s_width);
 382     png_free(png_ptr, info_ptr->scal_s_height);
 383     info_ptr->scal_s_width = NULL;
 384     info_ptr->scal_s_height = NULL;
 385 #endif
 386     info_ptr->valid &= ~PNG_INFO_sCAL;
 387 }
 388 #endif
 389
 390 #if defined(PNG_pCAL_SUPPORTED)
 391 /* free any pCAL entry */
 392 #ifdef PNG_FREE_ME_SUPPORTED
 393 if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
 394 #else
 395 if (mask & PNG_FREE_PCAL)
 396 #endif
 397 {
 398     png_free(png_ptr, info_ptr->pcal_purpose);
 399     png_free(png_ptr, info_ptr->pcal_units);
 400     info_ptr->pcal_purpose = NULL;
 401     info_ptr->pcal_units = NULL;
 402     if (info_ptr->pcal_params != NULL)
 403     {
 404         int i;
 405         for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
 406         {
 407           png_free(png_ptr, info_ptr->pcal_params[i]);
 408           info_ptr->pcal_params[i]=NULL;
 409         }
 410         png_free(png_ptr, info_ptr->pcal_params);
 411         info_ptr->pcal_params = NULL;
 412     }
 413     info_ptr->valid &= ~PNG_INFO_pCAL;
 414 }
 415 #endif
 416
 417 #if defined(PNG_iCCP_SUPPORTED)
 418 /* free any iCCP entry */
 419 #ifdef PNG_FREE_ME_SUPPORTED
 420 if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
 421 #else
 422 if (mask & PNG_FREE_ICCP)
 423 #endif
 424 {
 425     png_free(png_ptr, info_ptr->iccp_name);
 426     png_free(png_ptr, info_ptr->iccp_profile);
 427     info_ptr->iccp_name = NULL;
 428     info_ptr->iccp_profile = NULL;
 429     info_ptr->valid &= ~PNG_INFO_iCCP;
 430 }
 431 #endif
 432
 433 #if defined(PNG_sPLT_SUPPORTED)
 434 /* free a given sPLT entry, or (if num == -1) all sPLT entries */
 435 #ifdef PNG_FREE_ME_SUPPORTED
 436 if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
 437 #else
 438 if (mask & PNG_FREE_SPLT)
 439 #endif
 440 {
 441    if (num != -1)
 442    {
 443       if(info_ptr->splt_palettes)
 444       {
 445           png_free(png_ptr, info_ptr->splt_palettes[num].name);
 446           png_free(png_ptr, info_ptr->splt_palettes[num].entries);
 447           info_ptr->splt_palettes[num].name = NULL;
 448           info_ptr->splt_palettes[num].entries = NULL;
 449       }
 450    }
 451    else
 452    {
 453        if(info_ptr->splt_palettes_num)
 454        {
 455          int i;
 456          for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
 457             png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
 458
 459          png_free(png_ptr, info_ptr->splt_palettes);
 460          info_ptr->splt_palettes = NULL;
 461          info_ptr->splt_palettes_num = 0;
 462        }
 463        info_ptr->valid &= ~PNG_INFO_sPLT;
 464    }
 465 }
 466 #endif
 467
 468 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
 469 #ifdef PNG_FREE_ME_SUPPORTED
 470 if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
 471 #else
 472 if (mask & PNG_FREE_UNKN)
 473 #endif
 474 {
 475    if (num != -1)
 476    {
 477        if(info_ptr->unknown_chunks)
 478        {
 479           png_free(png_ptr, info_ptr->unknown_chunks[num].data);
 480           info_ptr->unknown_chunks[num].data = NULL;
 481        }
 482    }
 483    else
 484    {
 485        int i;
 486
 487        if(info_ptr->unknown_chunks_num)
 488        {
 489          for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
 490             png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
 491
 492          png_free(png_ptr, info_ptr->unknown_chunks);
 493          info_ptr->unknown_chunks = NULL;
 494          info_ptr->unknown_chunks_num = 0;
 495        }
 496    }
 497 }
 498 #endif
 499
 500 #if defined(PNG_hIST_SUPPORTED)
 501 /* free any hIST entry */
 502 #ifdef PNG_FREE_ME_SUPPORTED
 503 if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
 504 #else
 505 if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
 506 #endif
 507 {
 508     png_free(png_ptr, info_ptr->hist);
 509     info_ptr->hist = NULL;
 510     info_ptr->valid &= ~PNG_INFO_hIST;
 511 #ifndef PNG_FREE_ME_SUPPORTED
 512     png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
 513 #endif
 514 }
 515 #endif
 516
 517 /* free any PLTE entry that was internally allocated */
 518 #ifdef PNG_FREE_ME_SUPPORTED
 519 if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
 520 #else
 521 if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
 522 #endif
 523 {
 524     png_zfree(png_ptr, info_ptr->palette);
 525     info_ptr->palette = NULL;
 526     info_ptr->valid &= ~PNG_INFO_PLTE;
 527 #ifndef PNG_FREE_ME_SUPPORTED
 528     png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
 529 #endif
 530     info_ptr->num_palette = 0;
 531 }
 532
 533 #if defined(PNG_INFO_IMAGE_SUPPORTED)
 534 /* free any image bits attached to the info structure */
 535 #ifdef PNG_FREE_ME_SUPPORTED
 536 if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
 537 #else
 538 if (mask & PNG_FREE_ROWS)
 539 #endif
 540 {
 541     if(info_ptr->row_pointers)
 542     {
 543        int row;
 544        for (row = 0; row < (int)info_ptr->height; row++)
 545        {
 546           png_free(png_ptr, info_ptr->row_pointers[row]);
 547           info_ptr->row_pointers[row]=NULL;
 548        }
 549        png_free(png_ptr, info_ptr->row_pointers);
 550        info_ptr->row_pointers=NULL;
 551     }
 552     info_ptr->valid &= ~PNG_INFO_IDAT;
 553 }
 554 #endif
 555
 556 #ifdef PNG_FREE_ME_SUPPORTED
 557    if(num == -1)
 558      info_ptr->free_me &= ~mask;
 559    else
 560      info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
 561 #endif
 562 }
 563
 564 /* This is an internal routine to free any memory that the info struct is
 565  * pointing to before re-using it or freeing the struct itself.  Recall
 566  * that png_free() checks for NULL pointers for us.
 567  */
 568 void /* PRIVATE */
 569 png_info_destroy(png_structp png_ptr, png_infop info_ptr)
 570 {
 571    png_debug(1, "in png_info_destroy\n");
 572
 573    png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
 574
 575 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
 576    if (png_ptr->num_chunk_list)
 577    {
 578        png_free(png_ptr, png_ptr->chunk_list);
 579        png_ptr->chunk_list=NULL;
 580        png_ptr->num_chunk_list=0;
 581    }
 582 #endif
 583
 584    png_info_init_3(&info_ptr, sizeof(png_info));
 585 }
 586
 587 /* This function returns a pointer to the io_ptr associated with the user
 588  * functions.  The application should free any memory associated with this
 589  * pointer before png_write_destroy() or png_read_destroy() are called.
 590  */
 591 png_voidp PNGAPI
 592 png_get_io_ptr(png_structp png_ptr)
 593 {
 594    return (png_ptr->io_ptr);
 595 }
 596
 597 #if !defined(PNG_NO_STDIO)
 598 /* Initialize the default input/output functions for the PNG file.  If you
 599  * use your own read or write routines, you can call either png_set_read_fn()
 600  * or png_set_write_fn() instead of png_init_io().  If you have defined
 601  * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
 602  * necessarily available.
 603  */
 604 void PNGAPI
 605 png_init_io(png_structp png_ptr, png_FILE_p fp)
 606 {
 607    png_debug(1, "in png_init_io\n");
 608    png_ptr->io_ptr = (png_voidp)fp;
 609 }
 610 #endif
 611
 612 #if defined(PNG_TIME_RFC1123_SUPPORTED)
 613 /* Convert the supplied time into an RFC 1123 string suitable for use in
 614  * a "Creation Time" or other text-based time string.
 615  */
 616 png_charp PNGAPI
 617 png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
 618 {
 619    static PNG_CONST char short_months[12][4] =
 620         {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
 621          "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
 622
 623    if (png_ptr->time_buffer == NULL)
 624    {
 625       png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
 626          sizeof(char)));
 627    }
 628
 629 #if defined(_WIN32_WCE)
 630    {
 631       wchar_t time_buf[29];
 632       wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
 633           ptime->day % 32, short_months[(ptime->month - 1) % 12],
 634         ptime->year, ptime->hour % 24, ptime->minute % 60,
 635           ptime->second % 61);
 636       WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
 637           NULL, NULL);
 638    }
 639 #else
 640 #ifdef USE_FAR_KEYWORD
 641    {
 642       char near_time_buf[29];
 643       sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
 644           ptime->day % 32, short_months[(ptime->month - 1) % 12],
 645           ptime->year, ptime->hour % 24, ptime->minute % 60,
 646           ptime->second % 61);
 647       png_memcpy(png_ptr->time_buffer, near_time_buf,
 648           29*sizeof(char));
 649    }
 650 #else
 651    sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
 652        ptime->day % 32, short_months[(ptime->month - 1) % 12],
 653        ptime->year, ptime->hour % 24, ptime->minute % 60,
 654        ptime->second % 61);
 655 #endif
 656 #endif /* _WIN32_WCE */
 657    return ((png_charp)png_ptr->time_buffer);
 658 }
 659 #endif /* PNG_TIME_RFC1123_SUPPORTED */
 660
 661 #if 0
 662 /* Signature string for a PNG file. */
 663 png_bytep PNGAPI
 664 png_sig_bytes(void)
 665 {
 666    return ((png_bytep)"\211\120\116\107\015\012\032\012");
 667 }
 668 #endif
 669
 670 png_charp PNGAPI
 671 png_get_copyright(png_structp png_ptr)
 672 {
 673    if (png_ptr != NULL || png_ptr == NULL)  /* silence compiler warning */
 674    return ((png_charp) "\n libpng version 1.2.4 - July 8, 2002\n\
 675    Copyright (c) 1998-2002 Glenn Randers-Pehrson\n\
 676    Copyright (c) 1996-1997 Andreas Dilger\n\
 677    Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
 678    return ((png_charp) "");
 679 }
 680
 681 /* The following return the library version as a short string in the
 682  * format 1.0.0 through 99.99.99zz.  To get the version of *.h files used
 683  * with your application, print out PNG_LIBPNG_VER_STRING, which is defined
 684  * in png.h.
 685  */
 686
 687 png_charp PNGAPI
 688 png_get_libpng_ver(png_structp png_ptr)
 689 {
 690    /* Version of *.c files used when building libpng */
 691    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
 692       return((png_charp) "1.2.4");
 693    return((png_charp) "1.2.4");
 694 }
 695
 696 png_charp PNGAPI
 697 png_get_header_ver(png_structp png_ptr)
 698 {
 699    /* Version of *.h files used when building libpng */
 700    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
 701       return((png_charp) PNG_LIBPNG_VER_STRING);
 702    return((png_charp) PNG_LIBPNG_VER_STRING);
 703 }
 704
 705 png_charp PNGAPI
 706 png_get_header_version(png_structp png_ptr)
 707 {
 708    /* Returns longer string containing both version and date */
 709    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
 710       return((png_charp) PNG_HEADER_VERSION_STRING);
 711    return((png_charp) PNG_HEADER_VERSION_STRING);
 712 }
 713
 714 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 715 int PNGAPI
 716 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
 717 {
 718    /* check chunk_name and return "keep" value if it's on the list, else 0 */
 719    int i;
 720    png_bytep p;
 721    if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
 722       return 0;
 723    p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
 724    for (i = png_ptr->num_chunk_list; i; i--, p-=5)
 725       if (!png_memcmp(chunk_name, p, 4))
 726         return ((int)*(p+4));
 727    return 0;
 728 }
 729 #endif
 730
 731 /* This function, added to libpng-1.0.6g, is untested. */
 732 int PNGAPI
 733 png_reset_zstream(png_structp png_ptr)
 734 {
 735    return (inflateReset(&png_ptr->zstream));
 736 }
 737
 738 /* This function was added to libpng-1.0.7 */
 739 png_uint_32 PNGAPI
 740 png_access_version_number(void)
 741 {
 742    /* Version of *.c files used when building libpng */
 743    return((png_uint_32) 10204L);
 744 }
 745
 746
 747 #if !defined(PNG_1_0_X)
 748 #if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
 749     /* GRR:  could add this:   && defined(PNG_MMX_CODE_SUPPORTED) */
 750 /* this INTERNAL function was added to libpng 1.2.0 */
 751 void /* PRIVATE */
 752 png_init_mmx_flags (png_structp png_ptr)
 753 {
 754     png_ptr->mmx_rowbytes_threshold = 0;
 755     png_ptr->mmx_bitdepth_threshold = 0;
 756
 757 #  if (defined(PNG_USE_PNGVCRD) || defined(PNG_USE_PNGGCCRD))
 758
 759     png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_COMPILED;
 760
 761     if (png_mmx_support()) {
 762         png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
 763 #    ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
 764                               | PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
 765 #    endif
 766 #    ifdef PNG_HAVE_ASSEMBLER_READ_INTERLACE
 767                               | PNG_ASM_FLAG_MMX_READ_INTERLACE
 768 #    endif
 769 #    ifndef PNG_HAVE_ASSEMBLER_READ_FILTER_ROW
 770                               ;
 771 #    else
 772                               | PNG_ASM_FLAG_MMX_READ_FILTER_SUB
 773                               | PNG_ASM_FLAG_MMX_READ_FILTER_UP
 774                               | PNG_ASM_FLAG_MMX_READ_FILTER_AVG
 775                               | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
 776
 777         png_ptr->mmx_rowbytes_threshold = PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT;
 778         png_ptr->mmx_bitdepth_threshold = PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT;
 779 #    endif
 780     } else {
 781         png_ptr->asm_flags &= ~( PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
 782                                | PNG_MMX_READ_FLAGS
 783                                | PNG_MMX_WRITE_FLAGS );
 784     }
 785
 786 #  else /* !((PNGVCRD || PNGGCCRD) && PNG_ASSEMBLER_CODE_SUPPORTED)) */
 787
 788     /* clear all MMX flags; no support is compiled in */
 789     png_ptr->asm_flags &= ~( PNG_MMX_FLAGS );
 790
 791 #  endif /* ?(PNGVCRD || PNGGCCRD) */
 792 }
 793
 794 #endif /* !(PNG_ASSEMBLER_CODE_SUPPORTED) */
 795
 796 /* this function was added to libpng 1.2.0 */
 797 #if !defined(PNG_USE_PNGGCCRD) && \
 798     !(defined(PNG_ASSEMBLER_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
 799 int PNGAPI
 800 png_mmx_support(void)
 801 {
 802     return -1;
 803 }
 804 #endif
 805 #endif /* PNG_1_0_X */