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 #ifdef __VISAGECPP__
  86 const char png_libpng_ver[18] = "1.2.4";
  87 #endif
  88
  89 /* Tells libpng that we have already handled the first "num_bytes" bytes
  90  * of the PNG file signature.  If the PNG data is embedded into another
  91  * stream we can set num_bytes = 8 so that libpng will not attempt to read
  92  * or write any of the magic bytes before it starts on the IHDR.
  93  */
  94
  95 void PNGAPI
  96 png_set_sig_bytes(png_structp png_ptr, int num_bytes)
  97 {
  98    png_debug(1, "in png_set_sig_bytes\n");
  99    if (num_bytes > 8)
 100       png_error(png_ptr, "Too many bytes for PNG signature.");
 101
 102    png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
 103 }
 104
 105 /* Checks whether the supplied bytes match the PNG signature.  We allow
 106  * checking less than the full 8-byte signature so that those apps that
 107  * already read the first few bytes of a file to determine the file type
 108  * can simply check the remaining bytes for extra assurance.  Returns
 109  * an integer less than, equal to, or greater than zero if sig is found,
 110  * respectively, to be less than, to match, or be greater than the correct
 111  * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
 112  */
 113 int PNGAPI
 114 png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
 115 {
 116    png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
 117    if (num_to_check > 8)
 118       num_to_check = 8;
 119    else if (num_to_check < 1)
 120       return (0);
 121
 122    if (start > 7)
 123       return (0);
 124
 125    if (start + num_to_check > 8)
 126       num_to_check = 8 - start;
 127
 128    return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
 129 }
 130
 131 /* (Obsolete) function to check signature bytes.  It does not allow one
 132  * to check a partial signature.  This function might be removed in the
 133  * future - use png_sig_cmp().  Returns true (nonzero) if the file is a PNG.
 134  */
 135 int PNGAPI
 136 png_check_sig(png_bytep sig, int num)
 137 {
 138   return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
 139 }
 140
 141 /* Function to allocate memory for zlib and clear it to 0. */
 142 #ifdef PNG_1_0_X
 143 void PNGAPI
 144 #else
 145 voidpf /* private */
 146 #endif
 147 png_zalloc(voidpf png_ptr, uInt items, uInt size)
 148 {
 149    png_uint_32 num_bytes = (png_uint_32)items * size;
 150    png_voidp ptr;
 151    png_structp p=(png_structp)png_ptr;
 152    png_uint_32 save_flags=p->flags;
 153
 154    p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
 155    ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
 156    p->flags=save_flags;
 157
 158 #ifndef PNG_NO_ZALLOC_ZERO
 159    if (ptr == NULL)
 160        return ((voidpf)ptr);
 161
 162    if (num_bytes > (png_uint_32)0x8000L)
 163    {
 164       png_memset(ptr, 0, (png_size_t)0x8000L);
 165       png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
 166          (png_size_t)(num_bytes - (png_uint_32)0x8000L));
 167    }
 168    else
 169    {
 170       png_memset(ptr, 0, (png_size_t)num_bytes);
 171    }
 172 #endif
 173    return ((voidpf)ptr);
 174 }
 175
 176 /* function to free memory for zlib */
 177 #ifdef PNG_1_0_X
 178 void PNGAPI
 179 #else
 180 void /* private */
 181 #endif
 182 png_zfree(voidpf png_ptr, voidpf ptr)
 183 {
 184    png_free((png_structp)png_ptr, (png_voidp)ptr);
 185 }
 186
 187 /* Reset the CRC variable to 32 bits of 1's.  Care must be taken
 188  * in case CRC is > 32 bits to leave the top bits 0.
 189  */
 190 void /* PRIVATE */
 191 png_reset_crc(png_structp png_ptr)
 192 {
 193    png_ptr->crc = crc32(0, Z_NULL, 0);
 194 }
 195
 196 /* Calculate the CRC over a section of data.  We can only pass as
 197  * much data to this routine as the largest single buffer size.  We
 198  * also check that this data will actually be used before going to the
 199  * trouble of calculating it.
 200  */
 201 void /* PRIVATE */
 202 png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
 203 {
 204    int need_crc = 1;
 205
 206    if (png_ptr->chunk_name[0] & 0x20)                     /* ancillary */
 207    {
 208       if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
 209           (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
 210          need_crc = 0;
 211    }
 212    else                                                    /* critical */
 213    {
 214       if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
 215          need_crc = 0;
 216    }
 217
 218    if (need_crc)
 219       png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
 220 }
 221
 222 /* Allocate the memory for an info_struct for the application.  We don't
 223  * really need the png_ptr, but it could potentially be useful in the
 224  * future.  This should be used in favour of malloc(sizeof(png_info))
 225  * and png_info_init() so that applications that want to use a shared
 226  * libpng don't have to be recompiled if png_info changes size.
 227  */
 228 png_infop PNGAPI
 229 png_create_info_struct(png_structp png_ptr)
 230 {
 231    png_infop info_ptr;
 232
 233    png_debug(1, "in png_create_info_struct\n");
 234    if(png_ptr == NULL) return (NULL);
 235 #ifdef PNG_USER_MEM_SUPPORTED
 236    info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
 237       png_ptr->malloc_fn, png_ptr->mem_ptr);
 238 #else
 239    info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
 240 #endif
 241    if (info_ptr != NULL)
 242       png_info_init_3(&info_ptr, sizeof(png_info));
 243
 244    return (info_ptr);
 245 }
 246
 247 /* This function frees the memory associated with a single info struct.
 248  * Normally, one would use either png_destroy_read_struct() or
 249  * png_destroy_write_struct() to free an info struct, but this may be
 250  * useful for some applications.
 251  */
 252 void PNGAPI
 253 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
 254 {
 255    png_infop info_ptr = NULL;
 256
 257    png_debug(1, "in png_destroy_info_struct\n");
 258    if (info_ptr_ptr != NULL)
 259       info_ptr = *info_ptr_ptr;
 260
 261    if (info_ptr != NULL)
 262    {
 263       png_info_destroy(png_ptr, info_ptr);
 264
 265 #ifdef PNG_USER_MEM_SUPPORTED
 266       png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
 267           png_ptr->mem_ptr);
 268 #else
 269       png_destroy_struct((png_voidp)info_ptr);
 270 #endif
 271       *info_ptr_ptr = NULL;
 272    }
 273 }
 274
 275 /* Initialize the info structure.  This is now an internal function (0.89)
 276  * and applications using it are urged to use png_create_info_struct()
 277  * instead.
 278  */
 279 #undef png_info_init
 280 void PNGAPI
 281 png_info_init(png_infop info_ptr)
 282 {
 283    /* We only come here via pre-1.0.12-compiled applications */
 284    png_info_init_3(&info_ptr, 0);
 285 }
 286
 287 void PNGAPI
 288 png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
 289 {
 290    png_infop info_ptr = *ptr_ptr;
 291
 292    png_debug(1, "in png_info_init_3\n");
 293
 294    if(sizeof(png_info) > png_info_struct_size)
 295      {
 296        png_destroy_struct(info_ptr);
 297        info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
 298        *ptr_ptr = info_ptr;
 299      }
 300
 301    /* set everything to 0 */
 302    png_memset(info_ptr, 0, sizeof (png_info));
 303 }
 304
 305 #ifdef PNG_FREE_ME_SUPPORTED
 306 void PNGAPI
 307 png_data_freer(png_structp png_ptr, png_infop info_ptr,
 308    int freer, png_uint_32 mask)
 309 {
 310    png_debug(1, "in png_data_freer\n");
 311    if (png_ptr == NULL || info_ptr == NULL)
 312       return;
 313    if(freer == PNG_DESTROY_WILL_FREE_DATA)
 314       info_ptr->free_me |= mask;
 315    else if(freer == PNG_USER_WILL_FREE_DATA)
 316       info_ptr->free_me &= ~mask;
 317    else
 318       png_warning(png_ptr,
 319          "Unknown freer parameter in png_data_freer.");
 320 }
 321 #endif
 322
 323 void PNGAPI
 324 png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
 325    int num)
 326 {
 327    png_debug(1, "in png_free_data\n");
 328    if (png_ptr == NULL || info_ptr == NULL)
 329       return;
 330
 331 #if defined(PNG_TEXT_SUPPORTED)
 332 /* free text item num or (if num == -1) all text items */
 333 #ifdef PNG_FREE_ME_SUPPORTED
 334 if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
 335 #else
 336 if (mask & PNG_FREE_TEXT)
 337 #endif
 338 {
 339    if (num != -1)
 340    {
 341      if (info_ptr->text && info_ptr->text[num].key)
 342      {
 343          png_free(png_ptr, info_ptr->text[num].key);
 344          info_ptr->text[num].key = NULL;
 345      }
 346    }
 347    else
 348    {
 349        int i;
 350        for (i = 0; i < info_ptr->num_text; i++)
 351            png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
 352        png_free(png_ptr, info_ptr->text);
 353        info_ptr->text = NULL;
 354        info_ptr->num_text=0;
 355    }
 356 }
 357 #endif
 358
 359 #if defined(PNG_tRNS_SUPPORTED)
 360 /* free any tRNS entry */
 361 #ifdef PNG_FREE_ME_SUPPORTED
 362 if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
 363 #else
 364 if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
 365 #endif
 366 {
 367     png_free(png_ptr, info_ptr->trans);
 368     info_ptr->valid &= ~PNG_INFO_tRNS;
 369 #ifndef PNG_FREE_ME_SUPPORTED
 370     png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
 371 #endif
 372     info_ptr->trans = NULL;
 373 }
 374 #endif
 375
 376 #if defined(PNG_sCAL_SUPPORTED)
 377 /* free any sCAL entry */
 378 #ifdef PNG_FREE_ME_SUPPORTED
 379 if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
 380 #else
 381 if (mask & PNG_FREE_SCAL)
 382 #endif
 383 {
 384 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
 385     png_free(png_ptr, info_ptr->scal_s_width);
 386     png_free(png_ptr, info_ptr->scal_s_height);
 387     info_ptr->scal_s_width = NULL;
 388     info_ptr->scal_s_height = NULL;
 389 #endif
 390     info_ptr->valid &= ~PNG_INFO_sCAL;
 391 }
 392 #endif
 393
 394 #if defined(PNG_pCAL_SUPPORTED)
 395 /* free any pCAL entry */
 396 #ifdef PNG_FREE_ME_SUPPORTED
 397 if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
 398 #else
 399 if (mask & PNG_FREE_PCAL)
 400 #endif
 401 {
 402     png_free(png_ptr, info_ptr->pcal_purpose);
 403     png_free(png_ptr, info_ptr->pcal_units);
 404     info_ptr->pcal_purpose = NULL;
 405     info_ptr->pcal_units = NULL;
 406     if (info_ptr->pcal_params != NULL)
 407     {
 408         int i;
 409         for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
 410         {
 411           png_free(png_ptr, info_ptr->pcal_params[i]);
 412           info_ptr->pcal_params[i]=NULL;
 413         }
 414         png_free(png_ptr, info_ptr->pcal_params);
 415         info_ptr->pcal_params = NULL;
 416     }
 417     info_ptr->valid &= ~PNG_INFO_pCAL;
 418 }
 419 #endif
 420
 421 #if defined(PNG_iCCP_SUPPORTED)
 422 /* free any iCCP entry */
 423 #ifdef PNG_FREE_ME_SUPPORTED
 424 if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
 425 #else
 426 if (mask & PNG_FREE_ICCP)
 427 #endif
 428 {
 429     png_free(png_ptr, info_ptr->iccp_name);
 430     png_free(png_ptr, info_ptr->iccp_profile);
 431     info_ptr->iccp_name = NULL;
 432     info_ptr->iccp_profile = NULL;
 433     info_ptr->valid &= ~PNG_INFO_iCCP;
 434 }
 435 #endif
 436
 437 #if defined(PNG_sPLT_SUPPORTED)
 438 /* free a given sPLT entry, or (if num == -1) all sPLT entries */
 439 #ifdef PNG_FREE_ME_SUPPORTED
 440 if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
 441 #else
 442 if (mask & PNG_FREE_SPLT)
 443 #endif
 444 {
 445    if (num != -1)
 446    {
 447       if(info_ptr->splt_palettes)
 448       {
 449           png_free(png_ptr, info_ptr->splt_palettes[num].name);
 450           png_free(png_ptr, info_ptr->splt_palettes[num].entries);
 451           info_ptr->splt_palettes[num].name = NULL;
 452           info_ptr->splt_palettes[num].entries = NULL;
 453       }
 454    }
 455    else
 456    {
 457        if(info_ptr->splt_palettes_num)
 458        {
 459          int i;
 460          for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
 461             png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
 462
 463          png_free(png_ptr, info_ptr->splt_palettes);
 464          info_ptr->splt_palettes = NULL;
 465          info_ptr->splt_palettes_num = 0;
 466        }
 467        info_ptr->valid &= ~PNG_INFO_sPLT;
 468    }
 469 }
 470 #endif
 471
 472 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
 473 #ifdef PNG_FREE_ME_SUPPORTED
 474 if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
 475 #else
 476 if (mask & PNG_FREE_UNKN)
 477 #endif
 478 {
 479    if (num != -1)
 480    {
 481        if(info_ptr->unknown_chunks)
 482        {
 483           png_free(png_ptr, info_ptr->unknown_chunks[num].data);
 484           info_ptr->unknown_chunks[num].data = NULL;
 485        }
 486    }
 487    else
 488    {
 489        int i;
 490
 491        if(info_ptr->unknown_chunks_num)
 492        {
 493          for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
 494             png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
 495
 496          png_free(png_ptr, info_ptr->unknown_chunks);
 497          info_ptr->unknown_chunks = NULL;
 498          info_ptr->unknown_chunks_num = 0;
 499        }
 500    }
 501 }
 502 #endif
 503
 504 #if defined(PNG_hIST_SUPPORTED)
 505 /* free any hIST entry */
 506 #ifdef PNG_FREE_ME_SUPPORTED
 507 if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
 508 #else
 509 if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
 510 #endif
 511 {
 512     png_free(png_ptr, info_ptr->hist);
 513     info_ptr->hist = NULL;
 514     info_ptr->valid &= ~PNG_INFO_hIST;
 515 #ifndef PNG_FREE_ME_SUPPORTED
 516     png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
 517 #endif
 518 }
 519 #endif
 520
 521 /* free any PLTE entry that was internally allocated */
 522 #ifdef PNG_FREE_ME_SUPPORTED
 523 if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
 524 #else
 525 if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
 526 #endif
 527 {
 528     png_zfree(png_ptr, info_ptr->palette);
 529     info_ptr->palette = NULL;
 530     info_ptr->valid &= ~PNG_INFO_PLTE;
 531 #ifndef PNG_FREE_ME_SUPPORTED
 532     png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
 533 #endif
 534     info_ptr->num_palette = 0;
 535 }
 536
 537 #if defined(PNG_INFO_IMAGE_SUPPORTED)
 538 /* free any image bits attached to the info structure */
 539 #ifdef PNG_FREE_ME_SUPPORTED
 540 if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
 541 #else
 542 if (mask & PNG_FREE_ROWS)
 543 #endif
 544 {
 545     if(info_ptr->row_pointers)
 546     {
 547        int row;
 548        for (row = 0; row < (int)info_ptr->height; row++)
 549        {
 550           png_free(png_ptr, info_ptr->row_pointers[row]);
 551           info_ptr->row_pointers[row]=NULL;
 552        }
 553        png_free(png_ptr, info_ptr->row_pointers);
 554        info_ptr->row_pointers=NULL;
 555     }
 556     info_ptr->valid &= ~PNG_INFO_IDAT;
 557 }
 558 #endif
 559
 560 #ifdef PNG_FREE_ME_SUPPORTED
 561    if(num == -1)
 562      info_ptr->free_me &= ~mask;
 563    else
 564      info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
 565 #endif
 566 }
 567
 568 /* This is an internal routine to free any memory that the info struct is
 569  * pointing to before re-using it or freeing the struct itself.  Recall
 570  * that png_free() checks for NULL pointers for us.
 571  */
 572 void /* PRIVATE */
 573 png_info_destroy(png_structp png_ptr, png_infop info_ptr)
 574 {
 575    png_debug(1, "in png_info_destroy\n");
 576
 577    png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
 578
 579 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
 580    if (png_ptr->num_chunk_list)
 581    {
 582        png_free(png_ptr, png_ptr->chunk_list);
 583        png_ptr->chunk_list=NULL;
 584        png_ptr->num_chunk_list=0;
 585    }
 586 #endif
 587
 588    png_info_init_3(&info_ptr, sizeof(png_info));
 589 }
 590
 591 /* This function returns a pointer to the io_ptr associated with the user
 592  * functions.  The application should free any memory associated with this
 593  * pointer before png_write_destroy() or png_read_destroy() are called.
 594  */
 595 png_voidp PNGAPI
 596 png_get_io_ptr(png_structp png_ptr)
 597 {
 598    return (png_ptr->io_ptr);
 599 }
 600
 601 #if !defined(PNG_NO_STDIO)
 602 /* Initialize the default input/output functions for the PNG file.  If you
 603  * use your own read or write routines, you can call either png_set_read_fn()
 604  * or png_set_write_fn() instead of png_init_io().  If you have defined
 605  * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
 606  * necessarily available.
 607  */
 608 void PNGAPI
 609 png_init_io(png_structp png_ptr, png_FILE_p fp)
 610 {
 611    png_debug(1, "in png_init_io\n");
 612    png_ptr->io_ptr = (png_voidp)fp;
 613 }
 614 #endif
 615
 616 #if defined(PNG_TIME_RFC1123_SUPPORTED)
 617 /* Convert the supplied time into an RFC 1123 string suitable for use in
 618  * a "Creation Time" or other text-based time string.
 619  */
 620 png_charp PNGAPI
 621 png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
 622 {
 623    static PNG_CONST char short_months[12][4] =
 624         {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
 625          "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
 626
 627    if (png_ptr->time_buffer == NULL)
 628    {
 629       png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
 630          sizeof(char)));
 631    }
 632
 633 #if defined(_WIN32_WCE)
 634    {
 635       wchar_t time_buf[29];
 636       wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
 637           ptime->day % 32, short_months[(ptime->month - 1) % 12],
 638         ptime->year, ptime->hour % 24, ptime->minute % 60,
 639           ptime->second % 61);
 640       WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
 641           NULL, NULL);
 642    }
 643 #else
 644 #ifdef USE_FAR_KEYWORD
 645    {
 646       char near_time_buf[29];
 647       sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
 648           ptime->day % 32, short_months[(ptime->month - 1) % 12],
 649           ptime->year, ptime->hour % 24, ptime->minute % 60,
 650           ptime->second % 61);
 651       png_memcpy(png_ptr->time_buffer, near_time_buf,
 652           29*sizeof(char));
 653    }
 654 #else
 655    sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
 656        ptime->day % 32, short_months[(ptime->month - 1) % 12],
 657        ptime->year, ptime->hour % 24, ptime->minute % 60,
 658        ptime->second % 61);
 659 #endif
 660 #endif /* _WIN32_WCE */
 661    return ((png_charp)png_ptr->time_buffer);
 662 }
 663 #endif /* PNG_TIME_RFC1123_SUPPORTED */
 664
 665 #if 0
 666 /* Signature string for a PNG file. */
 667 png_bytep PNGAPI
 668 png_sig_bytes(void)
 669 {
 670    return ((png_bytep)"\211\120\116\107\015\012\032\012");
 671 }
 672 #endif
 673
 674 png_charp PNGAPI
 675 png_get_copyright(png_structp png_ptr)
 676 {
 677    if (png_ptr != NULL || png_ptr == NULL)  /* silence compiler warning */
 678    return ((png_charp) "\n libpng version 1.2.4 - July 8, 2002\n\
 679    Copyright (c) 1998-2002 Glenn Randers-Pehrson\n\
 680    Copyright (c) 1996-1997 Andreas Dilger\n\
 681    Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
 682    return ((png_charp) "");
 683 }
 684
 685 /* The following return the library version as a short string in the
 686  * format 1.0.0 through 99.99.99zz.  To get the version of *.h files used
 687  * with your application, print out PNG_LIBPNG_VER_STRING, which is defined
 688  * in png.h.
 689  */
 690
 691 png_charp PNGAPI
 692 png_get_libpng_ver(png_structp png_ptr)
 693 {
 694    /* Version of *.c files used when building libpng */
 695    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
 696       return((png_charp) "1.2.4");
 697    return((png_charp) "1.2.4");
 698 }
 699
 700 png_charp PNGAPI
 701 png_get_header_ver(png_structp png_ptr)
 702 {
 703    /* Version of *.h files used when building libpng */
 704    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
 705       return((png_charp) PNG_LIBPNG_VER_STRING);
 706    return((png_charp) PNG_LIBPNG_VER_STRING);
 707 }
 708
 709 png_charp PNGAPI
 710 png_get_header_version(png_structp png_ptr)
 711 {
 712    /* Returns longer string containing both version and date */
 713    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
 714       return((png_charp) PNG_HEADER_VERSION_STRING);
 715    return((png_charp) PNG_HEADER_VERSION_STRING);
 716 }
 717
 718 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 719 int PNGAPI
 720 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
 721 {
 722    /* check chunk_name and return "keep" value if it's on the list, else 0 */
 723    int i;
 724    png_bytep p;
 725    if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
 726       return 0;
 727    p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
 728    for (i = png_ptr->num_chunk_list; i; i--, p-=5)
 729       if (!png_memcmp(chunk_name, p, 4))
 730         return ((int)*(p+4));
 731    return 0;
 732 }
 733 #endif
 734
 735 /* This function, added to libpng-1.0.6g, is untested. */
 736 int PNGAPI
 737 png_reset_zstream(png_structp png_ptr)
 738 {
 739    return (inflateReset(&png_ptr->zstream));
 740 }
 741
 742 /* This function was added to libpng-1.0.7 */
 743 png_uint_32 PNGAPI
 744 png_access_version_number(void)
 745 {
 746    /* Version of *.c files used when building libpng */
 747    return((png_uint_32) 10204L);
 748 }
 749
 750
 751 #if !defined(PNG_1_0_X)
 752 #if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
 753     /* GRR:  could add this:   && defined(PNG_MMX_CODE_SUPPORTED) */
 754 /* this INTERNAL function was added to libpng 1.2.0 */
 755 void /* PRIVATE */
 756 png_init_mmx_flags (png_structp png_ptr)
 757 {
 758     png_ptr->mmx_rowbytes_threshold = 0;
 759     png_ptr->mmx_bitdepth_threshold = 0;
 760
 761 #  if (defined(PNG_USE_PNGVCRD) || defined(PNG_USE_PNGGCCRD))
 762
 763     png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_COMPILED;
 764
 765     if (png_mmx_support()) {
 766         png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
 767 #    ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
 768                               | PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
 769 #    endif
 770 #    ifdef PNG_HAVE_ASSEMBLER_READ_INTERLACE
 771                               | PNG_ASM_FLAG_MMX_READ_INTERLACE
 772 #    endif
 773 #    ifndef PNG_HAVE_ASSEMBLER_READ_FILTER_ROW
 774                               ;
 775 #    else
 776                               | PNG_ASM_FLAG_MMX_READ_FILTER_SUB
 777                               | PNG_ASM_FLAG_MMX_READ_FILTER_UP
 778                               | PNG_ASM_FLAG_MMX_READ_FILTER_AVG
 779                               | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
 780
 781         png_ptr->mmx_rowbytes_threshold = PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT;
 782         png_ptr->mmx_bitdepth_threshold = PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT;
 783 #    endif
 784     } else {
 785         png_ptr->asm_flags &= ~( PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
 786                                | PNG_MMX_READ_FLAGS
 787                                | PNG_MMX_WRITE_FLAGS );
 788     }
 789
 790 #  else /* !((PNGVCRD || PNGGCCRD) && PNG_ASSEMBLER_CODE_SUPPORTED)) */
 791
 792     /* clear all MMX flags; no support is compiled in */
 793     png_ptr->asm_flags &= ~( PNG_MMX_FLAGS );
 794
 795 #  endif /* ?(PNGVCRD || PNGGCCRD) */
 796 }
 797
 798 #endif /* !(PNG_ASSEMBLER_CODE_SUPPORTED) */
 799
 800 /* this function was added to libpng 1.2.0 */
 801 #if !defined(PNG_USE_PNGGCCRD) && \
 802     !(defined(PNG_ASSEMBLER_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
 803 int PNGAPI
 804 png_mmx_support(void)
 805 {
 806     return -1;
 807 }
 808 #endif
 809 #endif /* PNG_1_0_X */