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/thirdparty/libpng/png.c

http://crashrpt.googlecode.com/
C | 826 lines | 616 code | 92 blank | 118 comment | 110 complexity | 2ffce6485b39a4b8391ff665abafe315 MD5 | raw file
  1
  2/* png.c - location for general purpose libpng functions
  3 *
  4 * libpng version 1.2.7 - September 12, 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_7 Your_png_h_is_not_version_1_2_7;
 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
 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#undef png_info_init
283void PNGAPI
284png_info_init(png_infop info_ptr)
285{
286   /* We only come here via pre-1.0.12-compiled applications */
287   png_info_init_3(&info_ptr, 0);
288}
289
290void PNGAPI
291png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
292{
293   png_infop info_ptr = *ptr_ptr;
294
295   png_debug(1, "in png_info_init_3\n");
296
297   if(png_sizeof(png_info) > png_info_struct_size)
298     {
299       png_destroy_struct(info_ptr);
300       info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
301       *ptr_ptr = info_ptr;
302     }
303
304   /* set everything to 0 */
305   png_memset(info_ptr, 0, png_sizeof (png_info));
306}
307
308#ifdef PNG_FREE_ME_SUPPORTED
309void PNGAPI
310png_data_freer(png_structp png_ptr, png_infop info_ptr,
311   int freer, png_uint_32 mask)
312{
313   png_debug(1, "in png_data_freer\n");
314   if (png_ptr == NULL || info_ptr == NULL)
315      return;
316   if(freer == PNG_DESTROY_WILL_FREE_DATA)
317      info_ptr->free_me |= mask;
318   else if(freer == PNG_USER_WILL_FREE_DATA)
319      info_ptr->free_me &= ~mask;
320   else
321      png_warning(png_ptr,
322         "Unknown freer parameter in png_data_freer.");
323}
324#endif
325
326void PNGAPI
327png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
328   int num)
329{
330   png_debug(1, "in png_free_data\n");
331   if (png_ptr == NULL || info_ptr == NULL)
332      return;
333
334#if defined(PNG_TEXT_SUPPORTED)
335/* free text item num or (if num == -1) all text items */
336#ifdef PNG_FREE_ME_SUPPORTED
337if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
338#else
339if (mask & PNG_FREE_TEXT)
340#endif
341{
342   if (num != -1)
343   {
344     if (info_ptr->text && info_ptr->text[num].key)
345     {
346         png_free(png_ptr, info_ptr->text[num].key);
347         info_ptr->text[num].key = NULL;
348     }
349   }
350   else
351   {
352       int i;
353       for (i = 0; i < info_ptr->num_text; i++)
354           png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
355       png_free(png_ptr, info_ptr->text);
356       info_ptr->text = NULL;
357       info_ptr->num_text=0;
358   }
359}
360#endif
361
362#if defined(PNG_tRNS_SUPPORTED)
363/* free any tRNS entry */
364#ifdef PNG_FREE_ME_SUPPORTED
365if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
366#else
367if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
368#endif
369{
370    png_free(png_ptr, info_ptr->trans);
371    info_ptr->valid &= ~PNG_INFO_tRNS;
372#ifndef PNG_FREE_ME_SUPPORTED
373    png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
374#endif
375    info_ptr->trans = NULL;
376}
377#endif
378
379#if defined(PNG_sCAL_SUPPORTED)
380/* free any sCAL entry */
381#ifdef PNG_FREE_ME_SUPPORTED
382if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
383#else
384if (mask & PNG_FREE_SCAL)
385#endif
386{
387#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
388    png_free(png_ptr, info_ptr->scal_s_width);
389    png_free(png_ptr, info_ptr->scal_s_height);
390    info_ptr->scal_s_width = NULL;
391    info_ptr->scal_s_height = NULL;
392#endif
393    info_ptr->valid &= ~PNG_INFO_sCAL;
394}
395#endif
396
397#if defined(PNG_pCAL_SUPPORTED)
398/* free any pCAL entry */
399#ifdef PNG_FREE_ME_SUPPORTED
400if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
401#else
402if (mask & PNG_FREE_PCAL)
403#endif
404{
405    png_free(png_ptr, info_ptr->pcal_purpose);
406    png_free(png_ptr, info_ptr->pcal_units);
407    info_ptr->pcal_purpose = NULL;
408    info_ptr->pcal_units = NULL;
409    if (info_ptr->pcal_params != NULL)
410    {
411        int i;
412        for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
413        {
414          png_free(png_ptr, info_ptr->pcal_params[i]);
415          info_ptr->pcal_params[i]=NULL;
416        }
417        png_free(png_ptr, info_ptr->pcal_params);
418        info_ptr->pcal_params = NULL;
419    }
420    info_ptr->valid &= ~PNG_INFO_pCAL;
421}
422#endif
423
424#if defined(PNG_iCCP_SUPPORTED)
425/* free any iCCP entry */
426#ifdef PNG_FREE_ME_SUPPORTED
427if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
428#else
429if (mask & PNG_FREE_ICCP)
430#endif
431{
432    png_free(png_ptr, info_ptr->iccp_name);
433    png_free(png_ptr, info_ptr->iccp_profile);
434    info_ptr->iccp_name = NULL;
435    info_ptr->iccp_profile = NULL;
436    info_ptr->valid &= ~PNG_INFO_iCCP;
437}
438#endif
439
440#if defined(PNG_sPLT_SUPPORTED)
441/* free a given sPLT entry, or (if num == -1) all sPLT entries */
442#ifdef PNG_FREE_ME_SUPPORTED
443if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
444#else
445if (mask & PNG_FREE_SPLT)
446#endif
447{
448   if (num != -1)
449   {
450      if(info_ptr->splt_palettes)
451      {
452          png_free(png_ptr, info_ptr->splt_palettes[num].name);
453          png_free(png_ptr, info_ptr->splt_palettes[num].entries);
454          info_ptr->splt_palettes[num].name = NULL;
455          info_ptr->splt_palettes[num].entries = NULL;
456      }
457   }
458   else
459   {
460       if(info_ptr->splt_palettes_num)
461       {
462         int i;
463         for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
464            png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
465
466         png_free(png_ptr, info_ptr->splt_palettes);
467         info_ptr->splt_palettes = NULL;
468         info_ptr->splt_palettes_num = 0;
469       }
470       info_ptr->valid &= ~PNG_INFO_sPLT;
471   }
472}
473#endif
474
475#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
476#ifdef PNG_FREE_ME_SUPPORTED
477if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
478#else
479if (mask & PNG_FREE_UNKN)
480#endif
481{
482   if (num != -1)
483   {
484       if(info_ptr->unknown_chunks)
485       {
486          png_free(png_ptr, info_ptr->unknown_chunks[num].data);
487          info_ptr->unknown_chunks[num].data = NULL;
488       }
489   }
490   else
491   {
492       int i;
493
494       if(info_ptr->unknown_chunks_num)
495       {
496         for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
497            png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
498
499         png_free(png_ptr, info_ptr->unknown_chunks);
500         info_ptr->unknown_chunks = NULL;
501         info_ptr->unknown_chunks_num = 0;
502       }
503   }
504}
505#endif
506
507#if defined(PNG_hIST_SUPPORTED)
508/* free any hIST entry */
509#ifdef PNG_FREE_ME_SUPPORTED
510if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
511#else
512if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
513#endif
514{
515    png_free(png_ptr, info_ptr->hist);
516    info_ptr->hist = NULL;
517    info_ptr->valid &= ~PNG_INFO_hIST;
518#ifndef PNG_FREE_ME_SUPPORTED
519    png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
520#endif
521}
522#endif
523
524/* free any PLTE entry that was internally allocated */
525#ifdef PNG_FREE_ME_SUPPORTED
526if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
527#else
528if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
529#endif
530{
531    png_zfree(png_ptr, info_ptr->palette);
532    info_ptr->palette = NULL;
533    info_ptr->valid &= ~PNG_INFO_PLTE;
534#ifndef PNG_FREE_ME_SUPPORTED
535    png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
536#endif
537    info_ptr->num_palette = 0;
538}
539
540#if defined(PNG_INFO_IMAGE_SUPPORTED)
541/* free any image bits attached to the info structure */
542#ifdef PNG_FREE_ME_SUPPORTED
543if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
544#else
545if (mask & PNG_FREE_ROWS)
546#endif
547{
548    if(info_ptr->row_pointers)
549    {
550       int row;
551       for (row = 0; row < (int)info_ptr->height; row++)
552       {
553          png_free(png_ptr, info_ptr->row_pointers[row]);
554          info_ptr->row_pointers[row]=NULL;
555       }
556       png_free(png_ptr, info_ptr->row_pointers);
557       info_ptr->row_pointers=NULL;
558    }
559    info_ptr->valid &= ~PNG_INFO_IDAT;
560}
561#endif
562
563#ifdef PNG_FREE_ME_SUPPORTED
564   if(num == -1)
565     info_ptr->free_me &= ~mask;
566   else
567     info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
568#endif
569}
570
571/* This is an internal routine to free any memory that the info struct is
572 * pointing to before re-using it or freeing the struct itself.  Recall
573 * that png_free() checks for NULL pointers for us.
574 */
575void /* PRIVATE */
576png_info_destroy(png_structp png_ptr, png_infop info_ptr)
577{
578   png_debug(1, "in png_info_destroy\n");
579
580   png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
581
582#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
583   if (png_ptr->num_chunk_list)
584   {
585       png_free(png_ptr, png_ptr->chunk_list);
586       png_ptr->chunk_list=NULL;
587       png_ptr->num_chunk_list=0;
588   }
589#endif
590
591   png_info_init_3(&info_ptr, png_sizeof(png_info));
592}
593
594/* This function returns a pointer to the io_ptr associated with the user
595 * functions.  The application should free any memory associated with this
596 * pointer before png_write_destroy() or png_read_destroy() are called.
597 */
598png_voidp PNGAPI
599png_get_io_ptr(png_structp png_ptr)
600{
601   return (png_ptr->io_ptr);
602}
603
604#if !defined(PNG_NO_STDIO)
605/* Initialize the default input/output functions for the PNG file.  If you
606 * use your own read or write routines, you can call either png_set_read_fn()
607 * or png_set_write_fn() instead of png_init_io().  If you have defined
608 * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
609 * necessarily available.
610 */
611void PNGAPI
612png_init_io(png_structp png_ptr, png_FILE_p fp)
613{
614   png_debug(1, "in png_init_io\n");
615   png_ptr->io_ptr = (png_voidp)fp;
616}
617#endif
618
619#if defined(PNG_TIME_RFC1123_SUPPORTED)
620/* Convert the supplied time into an RFC 1123 string suitable for use in
621 * a "Creation Time" or other text-based time string.
622 */
623png_charp PNGAPI
624png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
625{
626   static PNG_CONST char short_months[12][4] =
627        {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
628         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
629
630   if (png_ptr->time_buffer == NULL)
631   {
632      png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
633         png_sizeof(char)));
634   }
635
636#if defined(_WIN32_WCE)
637   {
638      wchar_t time_buf[29];
639      wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
640          ptime->day % 32, short_months[(ptime->month - 1) % 12],
641        ptime->year, ptime->hour % 24, ptime->minute % 60,
642          ptime->second % 61);
643      WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
644          NULL, NULL);
645   }
646#else
647#ifdef USE_FAR_KEYWORD
648   {
649      char near_time_buf[29];
650      sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
651          ptime->day % 32, short_months[(ptime->month - 1) % 12],
652          ptime->year, ptime->hour % 24, ptime->minute % 60,
653          ptime->second % 61);
654      png_memcpy(png_ptr->time_buffer, near_time_buf,
655          29*png_sizeof(char));
656   }
657#else
658   sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
659       ptime->day % 32, short_months[(ptime->month - 1) % 12],
660       ptime->year, ptime->hour % 24, ptime->minute % 60,
661       ptime->second % 61);
662#endif
663#endif /* _WIN32_WCE */
664   return ((png_charp)png_ptr->time_buffer);
665}
666#endif /* PNG_TIME_RFC1123_SUPPORTED */
667
668#if 0
669/* Signature string for a PNG file. */
670png_bytep PNGAPI
671png_sig_bytes(void)
672{
673   return ((png_bytep)"\211\120\116\107\015\012\032\012");
674}
675#endif
676
677png_charp PNGAPI
678png_get_copyright(png_structp png_ptr)
679{
680   if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
681   return ((png_charp) "\n libpng version 1.2.7 - September 12, 2004\n\
682   Copyright (c) 1998-2004 Glenn Randers-Pehrson\n\
683   Copyright (c) 1996-1997 Andreas Dilger\n\
684   Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
685   return ((png_charp) "");
686}
687
688/* The following return the library version as a short string in the
689 * format 1.0.0 through 99.99.99zz.  To get the version of *.h files
690 * used with your application, print out PNG_LIBPNG_VER_STRING, which
691 * is defined in png.h.
692 * Note: now there is no difference between png_get_libpng_ver() and
693 * png_get_header_ver().  Due to the version_nn_nn_nn typedef guard,
694 * it is guaranteed that png.c uses the correct version of png.h.
695 */
696png_charp PNGAPI
697png_get_libpng_ver(png_structp png_ptr)
698{
699   /* Version of *.c 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) "");
703}
704
705png_charp PNGAPI
706png_get_header_ver(png_structp png_ptr)
707{
708   /* Version of *.h files used when building libpng */
709   if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
710      return ((png_charp) PNG_LIBPNG_VER_STRING);
711   return ((png_charp) "");
712}
713
714png_charp PNGAPI
715png_get_header_version(png_structp png_ptr)
716{
717   /* Returns longer string containing both version and date */
718   if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
719      return ((png_charp) PNG_HEADER_VERSION_STRING);
720   return ((png_charp) "");
721}
722
723#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
724int PNGAPI
725png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
726{
727   /* check chunk_name and return "keep" value if it's on the list, else 0 */
728   int i;
729   png_bytep p;
730   if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
731      return 0;
732   p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
733   for (i = png_ptr->num_chunk_list; i; i--, p-=5)
734      if (!png_memcmp(chunk_name, p, 4))
735        return ((int)*(p+4));
736   return 0;
737}
738#endif
739
740/* This function, added to libpng-1.0.6g, is untested. */
741int PNGAPI
742png_reset_zstream(png_structp png_ptr)
743{
744   return (inflateReset(&png_ptr->zstream));
745}
746
747/* This function was added to libpng-1.0.7 */
748png_uint_32 PNGAPI
749png_access_version_number(void)
750{
751   /* Version of *.c files used when building libpng */
752   return((png_uint_32) PNG_LIBPNG_VER);
753}
754
755
756#if !defined(PNG_1_0_X)
757#if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
758    /* GRR:  could add this:   && defined(PNG_MMX_CODE_SUPPORTED) */
759/* this INTERNAL function was added to libpng 1.2.0 */
760void /* PRIVATE */
761png_init_mmx_flags (png_structp png_ptr)
762{
763    png_ptr->mmx_rowbytes_threshold = 0;
764    png_ptr->mmx_bitdepth_threshold = 0;
765
766#  if (defined(PNG_USE_PNGVCRD) || defined(PNG_USE_PNGGCCRD))
767
768    png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_COMPILED;
769
770    if (png_mmx_support() > 0) {
771        png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
772#    ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
773                              | PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
774#    endif
775#    ifdef PNG_HAVE_ASSEMBLER_READ_INTERLACE
776                              | PNG_ASM_FLAG_MMX_READ_INTERLACE
777#    endif
778#    ifndef PNG_HAVE_ASSEMBLER_READ_FILTER_ROW
779                              ;
780#    else
781                              | PNG_ASM_FLAG_MMX_READ_FILTER_SUB
782                              | PNG_ASM_FLAG_MMX_READ_FILTER_UP
783                              | PNG_ASM_FLAG_MMX_READ_FILTER_AVG
784                              | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
785
786        png_ptr->mmx_rowbytes_threshold = PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT;
787        png_ptr->mmx_bitdepth_threshold = PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT;
788#    endif
789    } else {
790        png_ptr->asm_flags &= ~( PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
791                               | PNG_MMX_READ_FLAGS
792                               | PNG_MMX_WRITE_FLAGS );
793    }
794
795#  else /* !((PNGVCRD || PNGGCCRD) && PNG_ASSEMBLER_CODE_SUPPORTED)) */
796
797    /* clear all MMX flags; no support is compiled in */
798    png_ptr->asm_flags &= ~( PNG_MMX_FLAGS );
799
800#  endif /* ?(PNGVCRD || PNGGCCRD) */
801}
802
803#endif /* !(PNG_ASSEMBLER_CODE_SUPPORTED) */
804
805/* this function was added to libpng 1.2.0 */
806#if !defined(PNG_USE_PNGGCCRD) && \
807    !(defined(PNG_ASSEMBLER_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
808int PNGAPI
809png_mmx_support(void)
810{
811    return -1;
812}
813#endif
814#endif /* PNG_1_0_X */
815
816#ifdef PNG_SIZE_T
817/* Added at libpng version 1.2.6 */
818   PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));
819png_size_t PNGAPI
820png_convert_size(size_t size)
821{
822  if (size > (png_size_t)-1)
823     PNG_ABORT();  /* We haven't got access to png_ptr, so no png_error() */
824  return ((png_size_t)size);
825}
826#endif /* PNG_SIZE_T */