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/libpng/png.c

https://code.google.com/p/xee/
C | 828 lines | 618 code | 92 blank | 118 comment | 111 complexity | f88818cd80573a586f202496a8b6b728 MD5 | raw file
  1
  2/* png.c - location for general purpose libpng functions
  3 *
  4 * libpng version 1.2.8 - December 3, 2004
  5 * For conditions of distribution and use, see copyright notice in png.h
  6 * Copyright (c) 1998-2004 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. */
 16typedef version_1_2_8 Your_png_h_is_not_version_1_2_8;
 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 */
 23const char png_libpng_ver[18] = PNG_LIBPNG_VER_STRING;
 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. */
 27const 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 */
 30PNG_IHDR;
 31PNG_IDAT;
 32PNG_IEND;
 33PNG_PLTE;
 34PNG_bKGD;
 35PNG_cHRM;
 36PNG_gAMA;
 37PNG_hIST;
 38PNG_iCCP;
 39PNG_iTXt;
 40PNG_oFFs;
 41PNG_pCAL;
 42PNG_sCAL;
 43PNG_pHYs;
 44PNG_sBIT;
 45PNG_sPLT;
 46PNG_sRGB;
 47PNG_tEXt;
 48PNG_tIME;
 49PNG_tRNS;
 50PNG_zTXt;
 51
 52/* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 53
 54/* start of interlace block */
 55const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
 56
 57/* offset to next interlace block */
 58const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
 59
 60/* start of interlace block in the y direction */
 61const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
 62
 63/* offset to next interlace block in the y direction */
 64const 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
 68const 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
 73const 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 */
 77const int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
 78
 79/* Mask to determine which pixels to overwrite while displaying */
 80const int FARDATA png_pass_dsp_mask[]
 81   = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
 82
 83#endif /* PNG_USE_GLOBAL_ARRAYS */
 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
 91void PNGAPI
 92png_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 */
109int PNGAPI
110png_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 */
131int PNGAPI
132png_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
139voidpf PNGAPI
140#else
141voidpf /* private */
142#endif
143png_zalloc(voidpf png_ptr, uInt items, uInt size)
144{
145   png_voidp ptr;
146   png_structp p=png_ptr;
147   png_uint_32 save_flags=p->flags;
148   png_uint_32 num_bytes;
149
150   if (items > PNG_UINT_32_MAX/size)
151   {
152     png_warning (png_ptr, "Potential overflow in png_zalloc()");
153     return (NULL);
154   }
155   num_bytes = (png_uint_32)items * size;
156
157   p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
158   ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
159   p->flags=save_flags;
160
161#if defined(PNG_1_0_X) && !defined(PNG_NO_ZALLOC_ZERO)
162   if (ptr == NULL)
163       return ((voidpf)ptr);
164
165   if (num_bytes > (png_uint_32)0x8000L)
166   {
167      png_memset(ptr, 0, (png_size_t)0x8000L);
168      png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
169         (png_size_t)(num_bytes - (png_uint_32)0x8000L));
170   }
171   else
172   {
173      png_memset(ptr, 0, (png_size_t)num_bytes);
174   }
175#endif
176   return ((voidpf)ptr);
177}
178
179/* function to free memory for zlib */
180#ifdef PNG_1_0_X
181void PNGAPI
182#else
183void /* private */
184#endif
185png_zfree(voidpf png_ptr, voidpf ptr)
186{
187   png_free((png_structp)png_ptr, (png_voidp)ptr);
188}
189
190/* Reset the CRC variable to 32 bits of 1's.  Care must be taken
191 * in case CRC is > 32 bits to leave the top bits 0.
192 */
193void /* PRIVATE */
194png_reset_crc(png_structp png_ptr)
195{
196   png_ptr->crc = crc32(0, Z_NULL, 0);
197}
198
199/* Calculate the CRC over a section of data.  We can only pass as
200 * much data to this routine as the largest single buffer size.  We
201 * also check that this data will actually be used before going to the
202 * trouble of calculating it.
203 */
204void /* PRIVATE */
205png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
206{
207   int need_crc = 1;
208
209   if (png_ptr->chunk_name[0] & 0x20)                     /* ancillary */
210   {
211      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
212          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
213         need_crc = 0;
214   }
215   else                                                    /* critical */
216   {
217      if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
218         need_crc = 0;
219   }
220
221   if (need_crc)
222      png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
223}
224
225/* Allocate the memory for an info_struct for the application.  We don't
226 * really need the png_ptr, but it could potentially be useful in the
227 * future.  This should be used in favour of malloc(png_sizeof(png_info))
228 * and png_info_init() so that applications that want to use a shared
229 * libpng don't have to be recompiled if png_info changes size.
230 */
231png_infop PNGAPI
232png_create_info_struct(png_structp png_ptr)
233{
234   png_infop info_ptr;
235
236   png_debug(1, "in png_create_info_struct\n");
237   if(png_ptr == NULL) return (NULL);
238#ifdef PNG_USER_MEM_SUPPORTED
239   info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
240      png_ptr->malloc_fn, png_ptr->mem_ptr);
241#else
242   info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
243#endif
244   if (info_ptr != NULL)
245      png_info_init_3(&info_ptr, png_sizeof(png_info));
246
247   return (info_ptr);
248}
249
250/* This function frees the memory associated with a single info struct.
251 * Normally, one would use either png_destroy_read_struct() or
252 * png_destroy_write_struct() to free an info struct, but this may be
253 * useful for some applications.
254 */
255void PNGAPI
256png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
257{
258   png_infop info_ptr = NULL;
259
260   png_debug(1, "in png_destroy_info_struct\n");
261   if (info_ptr_ptr != NULL)
262      info_ptr = *info_ptr_ptr;
263
264   if (info_ptr != NULL)
265   {
266      png_info_destroy(png_ptr, info_ptr);
267
268#ifdef PNG_USER_MEM_SUPPORTED
269      png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
270          png_ptr->mem_ptr);
271#else
272      png_destroy_struct((png_voidp)info_ptr);
273#endif
274      *info_ptr_ptr = NULL;
275   }
276}
277
278/* Initialize the info structure.  This is now an internal function (0.89)
279 * and applications using it are urged to use png_create_info_struct()
280 * instead.
281 */
282#if defined(PNG_1_0_X) || defined (PNG_1_2_X)
283#undef png_info_init
284void PNGAPI
285png_info_init(png_infop info_ptr)
286{
287   /* We only come here via pre-1.0.12-compiled applications */
288   png_info_init_3(&info_ptr, 0);
289}
290#endif
291
292void PNGAPI
293png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
294{
295   png_infop info_ptr = *ptr_ptr;
296
297   png_debug(1, "in png_info_init_3\n");
298
299   if(png_sizeof(png_info) > png_info_struct_size)
300     {
301       png_destroy_struct(info_ptr);
302       info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
303       *ptr_ptr = info_ptr;
304     }
305
306   /* set everything to 0 */
307   png_memset(info_ptr, 0, png_sizeof (png_info));
308}
309
310#ifdef PNG_FREE_ME_SUPPORTED
311void PNGAPI
312png_data_freer(png_structp png_ptr, png_infop info_ptr,
313   int freer, png_uint_32 mask)
314{
315   png_debug(1, "in png_data_freer\n");
316   if (png_ptr == NULL || info_ptr == NULL)
317      return;
318   if(freer == PNG_DESTROY_WILL_FREE_DATA)
319      info_ptr->free_me |= mask;
320   else if(freer == PNG_USER_WILL_FREE_DATA)
321      info_ptr->free_me &= ~mask;
322   else
323      png_warning(png_ptr,
324         "Unknown freer parameter in png_data_freer.");
325}
326#endif
327
328void PNGAPI
329png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
330   int num)
331{
332   png_debug(1, "in png_free_data\n");
333   if (png_ptr == NULL || info_ptr == NULL)
334      return;
335
336#if defined(PNG_TEXT_SUPPORTED)
337/* free text item num or (if num == -1) all text items */
338#ifdef PNG_FREE_ME_SUPPORTED
339if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
340#else
341if (mask & PNG_FREE_TEXT)
342#endif
343{
344   if (num != -1)
345   {
346     if (info_ptr->text && info_ptr->text[num].key)
347     {
348         png_free(png_ptr, info_ptr->text[num].key);
349         info_ptr->text[num].key = NULL;
350     }
351   }
352   else
353   {
354       int i;
355       for (i = 0; i < info_ptr->num_text; i++)
356           png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
357       png_free(png_ptr, info_ptr->text);
358       info_ptr->text = NULL;
359       info_ptr->num_text=0;
360   }
361}
362#endif
363
364#if defined(PNG_tRNS_SUPPORTED)
365/* free any tRNS entry */
366#ifdef PNG_FREE_ME_SUPPORTED
367if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
368#else
369if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
370#endif
371{
372    png_free(png_ptr, info_ptr->trans);
373    info_ptr->valid &= ~PNG_INFO_tRNS;
374#ifndef PNG_FREE_ME_SUPPORTED
375    png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
376#endif
377    info_ptr->trans = NULL;
378}
379#endif
380
381#if defined(PNG_sCAL_SUPPORTED)
382/* free any sCAL entry */
383#ifdef PNG_FREE_ME_SUPPORTED
384if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
385#else
386if (mask & PNG_FREE_SCAL)
387#endif
388{
389#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
390    png_free(png_ptr, info_ptr->scal_s_width);
391    png_free(png_ptr, info_ptr->scal_s_height);
392    info_ptr->scal_s_width = NULL;
393    info_ptr->scal_s_height = NULL;
394#endif
395    info_ptr->valid &= ~PNG_INFO_sCAL;
396}
397#endif
398
399#if defined(PNG_pCAL_SUPPORTED)
400/* free any pCAL entry */
401#ifdef PNG_FREE_ME_SUPPORTED
402if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
403#else
404if (mask & PNG_FREE_PCAL)
405#endif
406{
407    png_free(png_ptr, info_ptr->pcal_purpose);
408    png_free(png_ptr, info_ptr->pcal_units);
409    info_ptr->pcal_purpose = NULL;
410    info_ptr->pcal_units = NULL;
411    if (info_ptr->pcal_params != NULL)
412    {
413        int i;
414        for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
415        {
416          png_free(png_ptr, info_ptr->pcal_params[i]);
417          info_ptr->pcal_params[i]=NULL;
418        }
419        png_free(png_ptr, info_ptr->pcal_params);
420        info_ptr->pcal_params = NULL;
421    }
422    info_ptr->valid &= ~PNG_INFO_pCAL;
423}
424#endif
425
426#if defined(PNG_iCCP_SUPPORTED)
427/* free any iCCP entry */
428#ifdef PNG_FREE_ME_SUPPORTED
429if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
430#else
431if (mask & PNG_FREE_ICCP)
432#endif
433{
434    png_free(png_ptr, info_ptr->iccp_name);
435    png_free(png_ptr, info_ptr->iccp_profile);
436    info_ptr->iccp_name = NULL;
437    info_ptr->iccp_profile = NULL;
438    info_ptr->valid &= ~PNG_INFO_iCCP;
439}
440#endif
441
442#if defined(PNG_sPLT_SUPPORTED)
443/* free a given sPLT entry, or (if num == -1) all sPLT entries */
444#ifdef PNG_FREE_ME_SUPPORTED
445if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
446#else
447if (mask & PNG_FREE_SPLT)
448#endif
449{
450   if (num != -1)
451   {
452      if(info_ptr->splt_palettes)
453      {
454          png_free(png_ptr, info_ptr->splt_palettes[num].name);
455          png_free(png_ptr, info_ptr->splt_palettes[num].entries);
456          info_ptr->splt_palettes[num].name = NULL;
457          info_ptr->splt_palettes[num].entries = NULL;
458      }
459   }
460   else
461   {
462       if(info_ptr->splt_palettes_num)
463       {
464         int i;
465         for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
466            png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
467
468         png_free(png_ptr, info_ptr->splt_palettes);
469         info_ptr->splt_palettes = NULL;
470         info_ptr->splt_palettes_num = 0;
471       }
472       info_ptr->valid &= ~PNG_INFO_sPLT;
473   }
474}
475#endif
476
477#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
478#ifdef PNG_FREE_ME_SUPPORTED
479if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
480#else
481if (mask & PNG_FREE_UNKN)
482#endif
483{
484   if (num != -1)
485   {
486       if(info_ptr->unknown_chunks)
487       {
488          png_free(png_ptr, info_ptr->unknown_chunks[num].data);
489          info_ptr->unknown_chunks[num].data = NULL;
490       }
491   }
492   else
493   {
494       int i;
495
496       if(info_ptr->unknown_chunks_num)
497       {
498         for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
499            png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
500
501         png_free(png_ptr, info_ptr->unknown_chunks);
502         info_ptr->unknown_chunks = NULL;
503         info_ptr->unknown_chunks_num = 0;
504       }
505   }
506}
507#endif
508
509#if defined(PNG_hIST_SUPPORTED)
510/* free any hIST entry */
511#ifdef PNG_FREE_ME_SUPPORTED
512if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
513#else
514if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
515#endif
516{
517    png_free(png_ptr, info_ptr->hist);
518    info_ptr->hist = NULL;
519    info_ptr->valid &= ~PNG_INFO_hIST;
520#ifndef PNG_FREE_ME_SUPPORTED
521    png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
522#endif
523}
524#endif
525
526/* free any PLTE entry that was internally allocated */
527#ifdef PNG_FREE_ME_SUPPORTED
528if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
529#else
530if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
531#endif
532{
533    png_zfree(png_ptr, info_ptr->palette);
534    info_ptr->palette = NULL;
535    info_ptr->valid &= ~PNG_INFO_PLTE;
536#ifndef PNG_FREE_ME_SUPPORTED
537    png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
538#endif
539    info_ptr->num_palette = 0;
540}
541
542#if defined(PNG_INFO_IMAGE_SUPPORTED)
543/* free any image bits attached to the info structure */
544#ifdef PNG_FREE_ME_SUPPORTED
545if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
546#else
547if (mask & PNG_FREE_ROWS)
548#endif
549{
550    if(info_ptr->row_pointers)
551    {
552       int row;
553       for (row = 0; row < (int)info_ptr->height; row++)
554       {
555          png_free(png_ptr, info_ptr->row_pointers[row]);
556          info_ptr->row_pointers[row]=NULL;
557       }
558       png_free(png_ptr, info_ptr->row_pointers);
559       info_ptr->row_pointers=NULL;
560    }
561    info_ptr->valid &= ~PNG_INFO_IDAT;
562}
563#endif
564
565#ifdef PNG_FREE_ME_SUPPORTED
566   if(num == -1)
567     info_ptr->free_me &= ~mask;
568   else
569     info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
570#endif
571}
572
573/* This is an internal routine to free any memory that the info struct is
574 * pointing to before re-using it or freeing the struct itself.  Recall
575 * that png_free() checks for NULL pointers for us.
576 */
577void /* PRIVATE */
578png_info_destroy(png_structp png_ptr, png_infop info_ptr)
579{
580   png_debug(1, "in png_info_destroy\n");
581
582   png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
583
584#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
585   if (png_ptr->num_chunk_list)
586   {
587       png_free(png_ptr, png_ptr->chunk_list);
588       png_ptr->chunk_list=NULL;
589       png_ptr->num_chunk_list=0;
590   }
591#endif
592
593   png_info_init_3(&info_ptr, png_sizeof(png_info));
594}
595
596/* This function returns a pointer to the io_ptr associated with the user
597 * functions.  The application should free any memory associated with this
598 * pointer before png_write_destroy() or png_read_destroy() are called.
599 */
600png_voidp PNGAPI
601png_get_io_ptr(png_structp png_ptr)
602{
603   return (png_ptr->io_ptr);
604}
605
606#if !defined(PNG_NO_STDIO)
607/* Initialize the default input/output functions for the PNG file.  If you
608 * use your own read or write routines, you can call either png_set_read_fn()
609 * or png_set_write_fn() instead of png_init_io().  If you have defined
610 * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
611 * necessarily available.
612 */
613void PNGAPI
614png_init_io(png_structp png_ptr, png_FILE_p fp)
615{
616   png_debug(1, "in png_init_io\n");
617   png_ptr->io_ptr = (png_voidp)fp;
618}
619#endif
620
621#if defined(PNG_TIME_RFC1123_SUPPORTED)
622/* Convert the supplied time into an RFC 1123 string suitable for use in
623 * a "Creation Time" or other text-based time string.
624 */
625png_charp PNGAPI
626png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
627{
628   static PNG_CONST char short_months[12][4] =
629        {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
630         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
631
632   if (png_ptr->time_buffer == NULL)
633   {
634      png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
635         png_sizeof(char)));
636   }
637
638#if defined(_WIN32_WCE)
639   {
640      wchar_t time_buf[29];
641      wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
642          ptime->day % 32, short_months[(ptime->month - 1) % 12],
643        ptime->year, ptime->hour % 24, ptime->minute % 60,
644          ptime->second % 61);
645      WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
646          NULL, NULL);
647   }
648#else
649#ifdef USE_FAR_KEYWORD
650   {
651      char near_time_buf[29];
652      sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
653          ptime->day % 32, short_months[(ptime->month - 1) % 12],
654          ptime->year, ptime->hour % 24, ptime->minute % 60,
655          ptime->second % 61);
656      png_memcpy(png_ptr->time_buffer, near_time_buf,
657          29*png_sizeof(char));
658   }
659#else
660   sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
661       ptime->day % 32, short_months[(ptime->month - 1) % 12],
662       ptime->year, ptime->hour % 24, ptime->minute % 60,
663       ptime->second % 61);
664#endif
665#endif /* _WIN32_WCE */
666   return ((png_charp)png_ptr->time_buffer);
667}
668#endif /* PNG_TIME_RFC1123_SUPPORTED */
669
670#if 0
671/* Signature string for a PNG file. */
672png_bytep PNGAPI
673png_sig_bytes(void)
674{
675   return ((png_bytep)"\211\120\116\107\015\012\032\012");
676}
677#endif
678
679png_charp PNGAPI
680png_get_copyright(png_structp png_ptr)
681{
682   if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
683   return ((png_charp) "\n libpng version 1.2.8 - December 3, 2004\n\
684   Copyright (c) 1998-2004 Glenn Randers-Pehrson\n\
685   Copyright (c) 1996-1997 Andreas Dilger\n\
686   Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
687   return ((png_charp) "");
688}
689
690/* The following return the library version as a short string in the
691 * format 1.0.0 through 99.99.99zz.  To get the version of *.h files
692 * used with your application, print out PNG_LIBPNG_VER_STRING, which
693 * is defined in png.h.
694 * Note: now there is no difference between png_get_libpng_ver() and
695 * png_get_header_ver().  Due to the version_nn_nn_nn typedef guard,
696 * it is guaranteed that png.c uses the correct version of png.h.
697 */
698png_charp PNGAPI
699png_get_libpng_ver(png_structp png_ptr)
700{
701   /* Version of *.c files used when building libpng */
702   if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
703      return ((png_charp) PNG_LIBPNG_VER_STRING);
704   return ((png_charp) "");
705}
706
707png_charp PNGAPI
708png_get_header_ver(png_structp png_ptr)
709{
710   /* Version of *.h files used when building libpng */
711   if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
712      return ((png_charp) PNG_LIBPNG_VER_STRING);
713   return ((png_charp) "");
714}
715
716png_charp PNGAPI
717png_get_header_version(png_structp png_ptr)
718{
719   /* Returns longer string containing both version and date */
720   if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
721      return ((png_charp) PNG_HEADER_VERSION_STRING);
722   return ((png_charp) "");
723}
724
725#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
726int PNGAPI
727png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
728{
729   /* check chunk_name and return "keep" value if it's on the list, else 0 */
730   int i;
731   png_bytep p;
732   if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
733      return 0;
734   p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
735   for (i = png_ptr->num_chunk_list; i; i--, p-=5)
736      if (!png_memcmp(chunk_name, p, 4))
737        return ((int)*(p+4));
738   return 0;
739}
740#endif
741
742/* This function, added to libpng-1.0.6g, is untested. */
743int PNGAPI
744png_reset_zstream(png_structp png_ptr)
745{
746   return (inflateReset(&png_ptr->zstream));
747}
748
749/* This function was added to libpng-1.0.7 */
750png_uint_32 PNGAPI
751png_access_version_number(void)
752{
753   /* Version of *.c files used when building libpng */
754   return((png_uint_32) PNG_LIBPNG_VER);
755}
756
757
758#if !defined(PNG_1_0_X)
759#if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
760    /* GRR:  could add this:   && defined(PNG_MMX_CODE_SUPPORTED) */
761/* this INTERNAL function was added to libpng 1.2.0 */
762void /* PRIVATE */
763png_init_mmx_flags (png_structp png_ptr)
764{
765    png_ptr->mmx_rowbytes_threshold = 0;
766    png_ptr->mmx_bitdepth_threshold = 0;
767
768#  if (defined(PNG_USE_PNGVCRD) || defined(PNG_USE_PNGGCCRD))
769
770    png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_COMPILED;
771
772    if (png_mmx_support() > 0) {
773        png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
774#    ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
775                              | PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
776#    endif
777#    ifdef PNG_HAVE_ASSEMBLER_READ_INTERLACE
778                              | PNG_ASM_FLAG_MMX_READ_INTERLACE
779#    endif
780#    ifndef PNG_HAVE_ASSEMBLER_READ_FILTER_ROW
781                              ;
782#    else
783                              | PNG_ASM_FLAG_MMX_READ_FILTER_SUB
784                              | PNG_ASM_FLAG_MMX_READ_FILTER_UP
785                              | PNG_ASM_FLAG_MMX_READ_FILTER_AVG
786                              | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
787
788        png_ptr->mmx_rowbytes_threshold = PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT;
789        png_ptr->mmx_bitdepth_threshold = PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT;
790#    endif
791    } else {
792        png_ptr->asm_flags &= ~( PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
793                               | PNG_MMX_READ_FLAGS
794                               | PNG_MMX_WRITE_FLAGS );
795    }
796
797#  else /* !((PNGVCRD || PNGGCCRD) && PNG_ASSEMBLER_CODE_SUPPORTED)) */
798
799    /* clear all MMX flags; no support is compiled in */
800    png_ptr->asm_flags &= ~( PNG_MMX_FLAGS );
801
802#  endif /* ?(PNGVCRD || PNGGCCRD) */
803}
804
805#endif /* !(PNG_ASSEMBLER_CODE_SUPPORTED) */
806
807/* this function was added to libpng 1.2.0 */
808#if !defined(PNG_USE_PNGGCCRD) && \
809    !(defined(PNG_ASSEMBLER_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
810int PNGAPI
811png_mmx_support(void)
812{
813    return -1;
814}
815#endif
816#endif /* PNG_1_0_X */
817
818#ifdef PNG_SIZE_T
819/* Added at libpng version 1.2.6 */
820   PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));
821png_size_t PNGAPI
822png_convert_size(size_t size)
823{
824  if (size > (png_size_t)-1)
825     PNG_ABORT();  /* We haven't got access to png_ptr, so no png_error() */
826  return ((png_size_t)size);
827}
828#endif /* PNG_SIZE_T */