compiler/libpng/png.c

   1
   2 /* png.c - location for general purpose libpng functions
   3  *
   4  * libpng version 1.0.10 - March 30, 2001
   5  * Copyright (c) 1998-2001 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_0_10 Your_png_h_is_not_version_1_0_10;
  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] = "1.0.10";
  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 voidpf PNGAPI
 139 png_zalloc(voidpf png_ptr, uInt items, uInt size)
 140 {
 141    png_uint_32 num_bytes = (png_uint_32)items * size;
 142    png_voidp ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
 143
 144 #ifndef PNG_NO_ZALLOC_ZERO
 145    if (num_bytes > (png_uint_32)0x8000L)
 146    {
 147       png_memset(ptr, 0, (png_size_t)0x8000L);
 148       png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
 149          (png_size_t)(num_bytes - (png_uint_32)0x8000L));
 150    }
 151    else
 152    {
 153       png_memset(ptr, 0, (png_size_t)num_bytes);
 154    }
 155 #endif
 156    return ((voidpf)ptr);
 157 }
 158
 159 /* function to free memory for zlib */
 160 void PNGAPI
 161 png_zfree(voidpf png_ptr, voidpf ptr)
 162 {
 163    png_free((png_structp)png_ptr, (png_voidp)ptr);
 164 }
 165
 166 /* Reset the CRC variable to 32 bits of 1's.  Care must be taken
 167  * in case CRC is > 32 bits to leave the top bits 0.
 168  */
 169 void /* PRIVATE */
 170 png_reset_crc(png_structp png_ptr)
 171 {
 172    png_ptr->crc = crc32(0, Z_NULL, 0);
 173 }
 174
 175 /* Calculate the CRC over a section of data.  We can only pass as
 176  * much data to this routine as the largest single buffer size.  We
 177  * also check that this data will actually be used before going to the
 178  * trouble of calculating it.
 179  */
 180 void /* PRIVATE */
 181 png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
 182 {
 183    int need_crc = 1;
 184
 185    if (png_ptr->chunk_name[0] & 0x20)                     /* ancillary */
 186    {
 187       if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
 188           (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
 189          need_crc = 0;
 190    }
 191    else                                                    /* critical */
 192    {
 193       if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
 194          need_crc = 0;
 195    }
 196
 197    if (need_crc)
 198       png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
 199 }
 200
 201 /* Allocate the memory for an info_struct for the application.  We don't
 202  * really need the png_ptr, but it could potentially be useful in the
 203  * future.  This should be used in favour of malloc(sizeof(png_info))
 204  * and png_info_init() so that applications that want to use a shared
 205  * libpng don't have to be recompiled if png_info changes size.
 206  */
 207 png_infop PNGAPI
 208 png_create_info_struct(png_structp png_ptr)
 209 {
 210    png_infop info_ptr;
 211
 212    png_debug(1, "in png_create_info_struct\n");
 213    if(png_ptr == NULL) return (NULL);
 214 #ifdef PNG_USER_MEM_SUPPORTED
 215    if ((info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
 216       png_ptr->malloc_fn)) != NULL)
 217 #else
 218    if ((info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO)) != NULL)
 219 #endif
 220    {
 221       png_info_init(info_ptr);
 222    }
 223
 224    return (info_ptr);
 225 }
 226
 227 /* This function frees the memory associated with a single info struct.
 228  * Normally, one would use either png_destroy_read_struct() or
 229  * png_destroy_write_struct() to free an info struct, but this may be
 230  * useful for some applications.
 231  */
 232 void PNGAPI
 233 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
 234 {
 235    png_infop info_ptr = NULL;
 236
 237    png_debug(1, "in png_destroy_info_struct\n");
 238    if (info_ptr_ptr != NULL)
 239       info_ptr = *info_ptr_ptr;
 240
 241    if (info_ptr != NULL)
 242    {
 243       png_info_destroy(png_ptr, info_ptr);
 244
 245 #ifdef PNG_USER_MEM_SUPPORTED
 246       png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn);
 247 #else
 248       png_destroy_struct((png_voidp)info_ptr);
 249 #endif
 250       *info_ptr_ptr = (png_infop)NULL;
 251    }
 252 }
 253
 254 /* Initialize the info structure.  This is now an internal function (0.89)
 255  * and applications using it are urged to use png_create_info_struct()
 256  * instead.
 257  */
 258 void PNGAPI
 259 png_info_init(png_infop info_ptr)
 260 {
 261    png_debug(1, "in png_info_init\n");
 262    /* set everything to 0 */
 263    png_memset(info_ptr, 0, sizeof (png_info));
 264 }
 265
 266 #ifdef PNG_FREE_ME_SUPPORTED
 267 void PNGAPI
 268 png_data_freer(png_structp png_ptr, png_infop info_ptr,
 269    int freer, png_uint_32 mask)
 270 {
 271    png_debug(1, "in png_data_freer\n");
 272    if (png_ptr == NULL || info_ptr == NULL)
 273       return;
 274    if(freer == PNG_DESTROY_WILL_FREE_DATA)
 275       info_ptr->free_me |= mask;
 276    else if(freer == PNG_USER_WILL_FREE_DATA)
 277       info_ptr->free_me &= ~mask;
 278    else
 279       png_warning(png_ptr,
 280          "Unknown freer parameter in png_data_freer.");
 281 }
 282 #endif
 283
 284 void PNGAPI
 285 png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, int num)
 286 {
 287    png_debug(1, "in png_free_data\n");
 288    if (png_ptr == NULL || info_ptr == NULL)
 289       return;
 290
 291 #if defined(PNG_TEXT_SUPPORTED)
 292 /* free text item num or (if num == -1) all text items */
 293 #ifdef PNG_FREE_ME_SUPPORTED
 294 if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
 295 #else
 296 if (mask & PNG_FREE_TEXT)
 297 #endif
 298 {
 299    if (num != -1)
 300    {
 301      if (info_ptr->text && info_ptr->text[num].key)
 302      {
 303          png_free(png_ptr, info_ptr->text[num].key);
 304          info_ptr->text[num].key = NULL;
 305      }
 306    }
 307    else
 308    {
 309        int i;
 310        for (i = 0; i < info_ptr->num_text; i++)
 311            png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
 312        png_free(png_ptr, info_ptr->text);
 313        info_ptr->text = NULL;
 314        info_ptr->num_text=0;
 315    }
 316 }
 317 #endif
 318
 319 #if defined(PNG_tRNS_SUPPORTED)
 320 /* free any tRNS entry */
 321 #ifdef PNG_FREE_ME_SUPPORTED
 322 if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
 323 #else
 324 if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
 325 #endif
 326 {
 327     png_free(png_ptr, info_ptr->trans);
 328     info_ptr->valid &= ~PNG_INFO_tRNS;
 329     info_ptr->trans = NULL;
 330 }
 331 #endif
 332
 333 #if defined(PNG_sCAL_SUPPORTED)
 334 /* free any sCAL entry */
 335 #ifdef PNG_FREE_ME_SUPPORTED
 336 if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
 337 #else
 338 if (mask & PNG_FREE_SCAL)
 339 #endif
 340 {
 341 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
 342     png_free(png_ptr, info_ptr->scal_s_width);
 343     png_free(png_ptr, info_ptr->scal_s_height);
 344     info_ptr->scal_s_width = NULL;
 345     info_ptr->scal_s_height = NULL;
 346 #endif
 347     info_ptr->valid &= ~PNG_INFO_sCAL;
 348 }
 349 #endif
 350
 351 #if defined(PNG_pCAL_SUPPORTED)
 352 /* free any pCAL entry */
 353 #ifdef PNG_FREE_ME_SUPPORTED
 354 if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
 355 #else
 356 if (mask & PNG_FREE_PCAL)
 357 #endif
 358 {
 359     png_free(png_ptr, info_ptr->pcal_purpose);
 360     png_free(png_ptr, info_ptr->pcal_units);
 361     info_ptr->pcal_purpose = NULL;
 362     info_ptr->pcal_units = NULL;
 363     if (info_ptr->pcal_params != NULL)
 364     {
 365         int i;
 366         for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
 367         {
 368           png_free(png_ptr, info_ptr->pcal_params[i]);
 369           info_ptr->pcal_params[i]=NULL;
 370         }
 371         png_free(png_ptr, info_ptr->pcal_params);
 372         info_ptr->pcal_params = NULL;
 373     }
 374     info_ptr->valid &= ~PNG_INFO_pCAL;
 375 }
 376 #endif
 377
 378 #if defined(PNG_iCCP_SUPPORTED)
 379 /* free any iCCP entry */
 380 #ifdef PNG_FREE_ME_SUPPORTED
 381 if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
 382 #else
 383 if (mask & PNG_FREE_ICCP)
 384 #endif
 385 {
 386     png_free(png_ptr, info_ptr->iccp_name);
 387     png_free(png_ptr, info_ptr->iccp_profile);
 388     info_ptr->iccp_name = NULL;
 389     info_ptr->iccp_profile = NULL;
 390     info_ptr->valid &= ~PNG_INFO_iCCP;
 391 }
 392 #endif
 393
 394 #if defined(PNG_sPLT_SUPPORTED)
 395 /* free a given sPLT entry, or (if num == -1) all sPLT entries */
 396 #ifdef PNG_FREE_ME_SUPPORTED
 397 if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
 398 #else
 399 if (mask & PNG_FREE_SPLT)
 400 #endif
 401 {
 402    if (num != -1)
 403    {
 404       if(info_ptr->splt_palettes)
 405       {
 406           png_free(png_ptr, info_ptr->splt_palettes[num].name);
 407           png_free(png_ptr, info_ptr->splt_palettes[num].entries);
 408           info_ptr->splt_palettes[num].name = NULL;
 409           info_ptr->splt_palettes[num].entries = NULL;
 410       }
 411    }
 412    else
 413    {
 414        if(info_ptr->splt_palettes_num)
 415        {
 416          int i;
 417          for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
 418             png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
 419
 420          png_free(png_ptr, info_ptr->splt_palettes);
 421          info_ptr->splt_palettes = NULL;
 422          info_ptr->splt_palettes_num = 0;
 423        }
 424        info_ptr->valid &= ~PNG_INFO_sPLT;
 425    }
 426 }
 427 #endif
 428
 429 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
 430 #ifdef PNG_FREE_ME_SUPPORTED
 431 if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
 432 #else
 433 if (mask & PNG_FREE_UNKN)
 434 #endif
 435 {
 436    if (num != -1)
 437    {
 438        if(info_ptr->unknown_chunks)
 439        {
 440           png_free(png_ptr, info_ptr->unknown_chunks[num].data);
 441           info_ptr->unknown_chunks[num].data = NULL;
 442        }
 443    }
 444    else
 445    {
 446        int i;
 447
 448        if(info_ptr->unknown_chunks_num)
 449        {
 450          for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
 451             png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
 452
 453          png_free(png_ptr, info_ptr->unknown_chunks);
 454          info_ptr->unknown_chunks = NULL;
 455          info_ptr->unknown_chunks_num = 0;
 456        }
 457    }
 458 }
 459 #endif
 460
 461 #if defined(PNG_hIST_SUPPORTED)
 462 /* free any hIST entry */
 463 #ifdef PNG_FREE_ME_SUPPORTED
 464 if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
 465 #else
 466 if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
 467 #endif
 468 {
 469     png_free(png_ptr, info_ptr->hist);
 470     info_ptr->hist = NULL;
 471     info_ptr->valid &= ~PNG_INFO_hIST;
 472 }
 473 #endif
 474
 475 /* free any PLTE entry that was internally allocated */
 476 #ifdef PNG_FREE_ME_SUPPORTED
 477 if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
 478 #else
 479 if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
 480 #endif
 481 {
 482     png_zfree(png_ptr, info_ptr->palette);
 483     info_ptr->palette = NULL;
 484     info_ptr->valid &= ~PNG_INFO_PLTE;
 485     info_ptr->num_palette = 0;
 486 }
 487
 488 #if defined(PNG_INFO_IMAGE_SUPPORTED)
 489 /* free any image bits attached to the info structure */
 490 #ifdef PNG_FREE_ME_SUPPORTED
 491 if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
 492 #else
 493 if (mask & PNG_FREE_ROWS)
 494 #endif
 495 {
 496     if(info_ptr->row_pointers)
 497     {
 498        int row;
 499        for (row = 0; row < (int)info_ptr->height; row++)
 500        {
 501           png_free(png_ptr, info_ptr->row_pointers[row]);
 502           info_ptr->row_pointers[row]=NULL;
 503        }
 504        png_free(png_ptr, info_ptr->row_pointers);
 505        info_ptr->row_pointers=NULL;
 506     }
 507     info_ptr->valid &= ~PNG_INFO_IDAT;
 508 }
 509 #endif
 510
 511 #ifdef PNG_FREE_ME_SUPPORTED
 512    if(num == -1)
 513      info_ptr->free_me &= ~mask;
 514    else
 515      info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
 516 #endif
 517 }
 518
 519 /* This is an internal routine to free any memory that the info struct is
 520  * pointing to before re-using it or freeing the struct itself.  Recall
 521  * that png_free() checks for NULL pointers for us.
 522  */
 523 void /* PRIVATE */
 524 png_info_destroy(png_structp png_ptr, png_infop info_ptr)
 525 {
 526    png_debug(1, "in png_info_destroy\n");
 527
 528    png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
 529
 530 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
 531    if (png_ptr->num_chunk_list)
 532    {
 533        png_free(png_ptr, png_ptr->chunk_list);
 534        png_ptr->chunk_list=NULL;
 535        png_ptr->num_chunk_list=0;
 536    }
 537 #endif
 538
 539    png_info_init(info_ptr);
 540 }
 541
 542 /* This function returns a pointer to the io_ptr associated with the user
 543  * functions.  The application should free any memory associated with this
 544  * pointer before png_write_destroy() or png_read_destroy() are called.
 545  */
 546 png_voidp PNGAPI
 547 png_get_io_ptr(png_structp png_ptr)
 548 {
 549    return (png_ptr->io_ptr);
 550 }
 551
 552 #if !defined(PNG_NO_STDIO)
 553 /* Initialize the default input/output functions for the PNG file.  If you
 554  * use your own read or write routines, you can call either png_set_read_fn()
 555  * or png_set_write_fn() instead of png_init_io().  If you have defined
 556  * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
 557  * necessarily available.
 558  */
 559 void PNGAPI
 560 png_init_io(png_structp png_ptr, png_FILE_p fp)
 561 {
 562    png_debug(1, "in png_init_io\n");
 563    png_ptr->io_ptr = (png_voidp)fp;
 564 }
 565 #endif
 566
 567 #if defined(PNG_TIME_RFC1123_SUPPORTED)
 568 /* Convert the supplied time into an RFC 1123 string suitable for use in
 569  * a "Creation Time" or other text-based time string.
 570  */
 571 png_charp PNGAPI
 572 png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
 573 {
 574    static PNG_CONST char short_months[12][4] =
 575         {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
 576          "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
 577
 578    if (png_ptr->time_buffer == NULL)
 579    {
 580       png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
 581          sizeof(char)));
 582    }
 583
 584 #if defined(_WIN32_WCE)
 585   {
 586      wchar_t time_buf[29];
 587      wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
 588               ptime->day % 32, short_months[(ptime->month - 1) % 12],
 589               ptime->year, ptime->hour % 24, ptime->minute % 60,
 590               ptime->second % 61);
 591      WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
 592         NULL, NULL);
 593   }
 594 #else
 595 #ifdef USE_FAR_KEYWORD
 596    {
 597       char near_time_buf[29];
 598       sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
 599                ptime->day % 32, short_months[(ptime->month - 1) % 12],
 600                ptime->year, ptime->hour % 24, ptime->minute % 60,
 601                ptime->second % 61);
 602       png_memcpy(png_ptr->time_buffer, near_time_buf,
 603       29*sizeof(char));
 604    }
 605 #else
 606    sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
 607                ptime->day % 32, short_months[(ptime->month - 1) % 12],
 608                ptime->year, ptime->hour % 24, ptime->minute % 60,
 609                ptime->second % 61);
 610 #endif
 611 #endif /* _WIN32_WCE */
 612    return ((png_charp)png_ptr->time_buffer);
 613 }
 614 #endif /* PNG_TIME_RFC1123_SUPPORTED */
 615
 616 #if 0
 617 /* Signature string for a PNG file. */
 618 png_bytep PNGAPI
 619 png_sig_bytes(void)
 620 {
 621    return ((png_bytep)"\211\120\116\107\015\012\032\012");
 622 }
 623 #endif
 624
 625 png_charp PNGAPI
 626 png_get_copyright(png_structp png_ptr)
 627 {
 628    if (png_ptr != NULL || png_ptr == NULL)  /* silence compiler warning */
 629    return ((png_charp) "\n libpng version 1.0.10 - March 30, 2001\n\
 630    Copyright (c) 1998-2001 Glenn Randers-Pehrson\n\
 631    Copyright (c) 1996, 1997 Andreas Dilger\n\
 632    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.\n");
 633    return ((png_charp) "");
 634 }
 635
 636 /* The following return the library version as a short string in the
 637  * format 1.0.0 through 99.99.99zz.  To get the version of *.h files used
 638  * with your application, print out PNG_LIBPNG_VER_STRING, which is defined
 639  * in png.h.
 640  */
 641
 642 png_charp PNGAPI
 643 png_get_libpng_ver(png_structp png_ptr)
 644 {
 645    /* Version of *.c files used when building libpng */
 646    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
 647       return((png_charp) "1.0.10");
 648    return((png_charp) "1.0.10");
 649 }
 650
 651 png_charp PNGAPI
 652 png_get_header_ver(png_structp png_ptr)
 653 {
 654    /* Version of *.h files used when building libpng */
 655    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
 656       return((png_charp) PNG_LIBPNG_VER_STRING);
 657    return((png_charp) PNG_LIBPNG_VER_STRING);
 658 }
 659
 660 png_charp PNGAPI
 661 png_get_header_version(png_structp png_ptr)
 662 {
 663    /* Returns longer string containing both version and date */
 664    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
 665       return((png_charp) PNG_HEADER_VERSION_STRING);
 666    return((png_charp) PNG_HEADER_VERSION_STRING);
 667 }
 668
 669 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 670 int PNGAPI
 671 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
 672 {
 673    /* check chunk_name and return "keep" value if it's on the list, else 0 */
 674    int i;
 675    png_bytep p;
 676    if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
 677       return 0;
 678    p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
 679    for (i = png_ptr->num_chunk_list; i; i--, p-=5)
 680       if (!png_memcmp(chunk_name, p, 4))
 681         return ((int)*(p+4));
 682    return 0;
 683 }
 684 #endif
 685
 686 /* This function, added to libpng-1.0.6g, is untested. */
 687 int PNGAPI
 688 png_reset_zstream(png_structp png_ptr)
 689 {
 690    return (inflateReset(&png_ptr->zstream));
 691 }
 692
 693 /* This function was added to libpng-1.0.7 */
 694 png_uint_32 PNGAPI
 695 png_access_version_number(void)
 696 {
 697    /* Version of *.c files used when building libpng */
 698    return((png_uint_32) 10010L);
 699 }
 700
 701
 702 #if 0 /* delay this until version 1.2.0 */
 703 /* this function was added to libpng 1.0.9 (porting aid to libpng-1.2.0) */
 704 #ifndef PNG_ASSEMBLER_CODE_SUPPORTED
 705 int PNGAPI
 706 png_mmx_support(void)
 707 {
 708     return -1;
 709 }
 710 #endif
 711 #endif /* 0 */