pngcrush  1.8.13
About: Pngcrush is an optimizer for PNG (Portable Network Graphics) files.
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pngerror.c
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1 
2 /* pngerror.c - stub functions for i/o and memory allocation
3  *
4  * Last changed in libpng 1.6.31 [July 27, 2017]
5  * Copyright (c) 1998-2002,2004,2006-2017 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  * This code is released under the libpng license.
10  * For conditions of distribution and use, see the disclaimer
11  * and license in png.h
12  *
13  * This file provides a location for all error handling. Users who
14  * need special error handling are expected to write replacement functions
15  * and use png_set_error_fn() to use those functions. See the instructions
16  * at each function.
17  */
18 
19 #include "pngpriv.h"
20 
21 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
22 
24  png_const_charp error_message)),PNG_NORETURN);
25 
26 #ifdef PNG_WARNINGS_SUPPORTED
27 static void /* PRIVATE */
29  png_const_charp warning_message));
30 #endif /* WARNINGS */
31 
32 /* This function is called whenever there is a fatal error. This function
33  * should not be changed. If there is a need to handle errors differently,
34  * you should supply a replacement error function and use png_set_error_fn()
35  * to replace the error function at run-time.
36  */
37 #ifdef PNG_ERROR_TEXT_SUPPORTED
39 png_error,(png_const_structrp png_ptr, png_const_charp error_message),
41 {
42 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
43  char msg[16];
44  if (png_ptr != NULL)
45  {
46  if ((png_ptr->flags &
48  {
49  if (*error_message == PNG_LITERAL_SHARP)
50  {
51  /* Strip "#nnnn " from beginning of error message. */
52  int offset;
53  for (offset = 1; offset<15; offset++)
54  if (error_message[offset] == ' ')
55  break;
56 
57  if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
58  {
59  int i;
60  for (i = 0; i < offset - 1; i++)
61  msg[i] = error_message[i + 1];
62  msg[i - 1] = '\0';
63  error_message = msg;
64  }
65 
66  else
67  error_message += offset;
68  }
69 
70  else
71  {
72  if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
73  {
74  msg[0] = '0';
75  msg[1] = '\0';
76  error_message = msg;
77  }
78  }
79  }
80  }
81 #endif
82  if (png_ptr != NULL && png_ptr->error_fn != NULL)
83  (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr),
84  error_message);
85 
86  /* If the custom handler doesn't exist, or if it returns,
87  use the default handler, which will not return. */
88  png_default_error(png_ptr, error_message);
89 }
90 #else
92 png_err,(png_const_structrp png_ptr),PNG_NORETURN)
93 {
94  /* Prior to 1.5.2 the error_fn received a NULL pointer, expressed
95  * erroneously as '\0', instead of the empty string "". This was
96  * apparently an error, introduced in libpng-1.2.20, and png_default_error
97  * will crash in this case.
98  */
99  if (png_ptr != NULL && png_ptr->error_fn != NULL)
100  (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), "");
101 
102  /* If the custom handler doesn't exist, or if it returns,
103  use the default handler, which will not return. */
104  png_default_error(png_ptr, "");
105 }
106 #endif /* ERROR_TEXT */
107 
108 /* Utility to safely appends strings to a buffer. This never errors out so
109  * error checking is not required in the caller.
110  */
111 size_t
112 png_safecat(png_charp buffer, size_t bufsize, size_t pos,
113  png_const_charp string)
114 {
115  if (buffer != NULL && pos < bufsize)
116  {
117  if (string != NULL)
118  while (*string != '\0' && pos < bufsize-1)
119  buffer[pos++] = *string++;
120 
121  buffer[pos] = '\0';
122  }
123 
124  return pos;
125 }
126 
127 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
128 /* Utility to dump an unsigned value into a buffer, given a start pointer and
129  * and end pointer (which should point just *beyond* the end of the buffer!)
130  * Returns the pointer to the start of the formatted string.
131  */
132 png_charp
134  png_alloc_size_t number)
135 {
136  int count = 0; /* number of digits output */
137  int mincount = 1; /* minimum number required */
138  int output = 0; /* digit output (for the fixed point format) */
139 
140  *--end = '\0';
141 
142  /* This is written so that the loop always runs at least once, even with
143  * number zero.
144  */
145  while (end > start && (number != 0 || count < mincount))
146  {
147 
148  static const char digits[] = "0123456789ABCDEF";
149 
150  switch (format)
151  {
153  /* Needs five digits (the fraction) */
154  mincount = 5;
155  if (output != 0 || number % 10 != 0)
156  {
157  *--end = digits[number % 10];
158  output = 1;
159  }
160  number /= 10;
161  break;
162 
164  /* Expects at least 2 digits. */
165  mincount = 2;
166  /* FALLTHROUGH */
167 
168  case PNG_NUMBER_FORMAT_u:
169  *--end = digits[number % 10];
170  number /= 10;
171  break;
172 
174  /* This format expects at least two digits */
175  mincount = 2;
176  /* FALLTHROUGH */
177 
178  case PNG_NUMBER_FORMAT_x:
179  *--end = digits[number & 0xf];
180  number >>= 4;
181  break;
182 
183  default: /* an error */
184  number = 0;
185  break;
186  }
187 
188  /* Keep track of the number of digits added */
189  ++count;
190 
191  /* Float a fixed number here: */
192  if ((format == PNG_NUMBER_FORMAT_fixed) && (count == 5) && (end > start))
193  {
194  /* End of the fraction, but maybe nothing was output? In that case
195  * drop the decimal point. If the number is a true zero handle that
196  * here.
197  */
198  if (output != 0)
199  *--end = '.';
200  else if (number == 0) /* and !output */
201  *--end = '0';
202  }
203  }
204 
205  return end;
206 }
207 #endif
208 
209 #ifdef PNG_WARNINGS_SUPPORTED
210 /* This function is called whenever there is a non-fatal error. This function
211  * should not be changed. If there is a need to handle warnings differently,
212  * you should supply a replacement warning function and use
213  * png_set_error_fn() to replace the warning function at run-time.
214  */
215 void PNGAPI
217 {
218  int offset = 0;
219  if (png_ptr != NULL)
220  {
221 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
222  if ((png_ptr->flags &
224 #endif
225  {
226  if (*warning_message == PNG_LITERAL_SHARP)
227  {
228  for (offset = 1; offset < 15; offset++)
229  if (warning_message[offset] == ' ')
230  break;
231  }
232  }
233  }
234  if (png_ptr != NULL && png_ptr->warning_fn != NULL)
235  (*(png_ptr->warning_fn))(png_constcast(png_structrp,png_ptr),
236  warning_message + offset);
237  else
238  png_default_warning(png_ptr, warning_message + offset);
239 }
240 
241 /* These functions support 'formatted' warning messages with up to
242  * PNG_WARNING_PARAMETER_COUNT parameters. In the format string the parameter
243  * is introduced by @<number>, where 'number' starts at 1. This follows the
244  * standard established by X/Open for internationalizable error messages.
245  */
246 void
248  png_const_charp string)
249 {
250  if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT)
251  (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string);
252 }
253 
254 void
256  png_alloc_size_t value)
257 {
259  png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value));
260 }
261 
262 void
264  png_int_32 value)
265 {
267  png_charp str;
269 
270  /* Avoid overflow by doing the negate in a png_alloc_size_t: */
271  u = (png_alloc_size_t)value;
272  if (value < 0)
273  u = ~u + 1;
274 
275  str = PNG_FORMAT_NUMBER(buffer, format, u);
276 
277  if (value < 0 && str > buffer)
278  *--str = '-';
279 
280  png_warning_parameter(p, number, str);
281 }
282 
283 void
285  png_const_charp message)
286 {
287  /* The internal buffer is just 192 bytes - enough for all our messages,
288  * overflow doesn't happen because this code checks! If someone figures
289  * out how to send us a message longer than 192 bytes, all that will
290  * happen is that the message will be truncated appropriately.
291  */
292  size_t i = 0; /* Index in the msg[] buffer: */
293  char msg[192];
294 
295  /* Each iteration through the following loop writes at most one character
296  * to msg[i++] then returns here to validate that there is still space for
297  * the trailing '\0'. It may (in the case of a parameter) read more than
298  * one character from message[]; it must check for '\0' and continue to the
299  * test if it finds the end of string.
300  */
301  while (i<(sizeof msg)-1 && *message != '\0')
302  {
303  /* '@' at end of string is now just printed (previously it was skipped);
304  * it is an error in the calling code to terminate the string with @.
305  */
306  if (p != NULL && *message == '@' && message[1] != '\0')
307  {
308  int parameter_char = *++message; /* Consume the '@' */
309  static const char valid_parameters[] = "123456789";
310  int parameter = 0;
311 
312  /* Search for the parameter digit, the index in the string is the
313  * parameter to use.
314  */
315  while (valid_parameters[parameter] != parameter_char &&
316  valid_parameters[parameter] != '\0')
317  ++parameter;
318 
319  /* If the parameter digit is out of range it will just get printed. */
320  if (parameter < PNG_WARNING_PARAMETER_COUNT)
321  {
322  /* Append this parameter */
323  png_const_charp parm = p[parameter];
324  png_const_charp pend = p[parameter] + (sizeof p[parameter]);
325 
326  /* No need to copy the trailing '\0' here, but there is no guarantee
327  * that parm[] has been initialized, so there is no guarantee of a
328  * trailing '\0':
329  */
330  while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend)
331  msg[i++] = *parm++;
332 
333  /* Consume the parameter digit too: */
334  ++message;
335  continue;
336  }
337 
338  /* else not a parameter and there is a character after the @ sign; just
339  * copy that. This is known not to be '\0' because of the test above.
340  */
341  }
342 
343  /* At this point *message can't be '\0', even in the bad parameter case
344  * above where there is a lone '@' at the end of the message string.
345  */
346  msg[i++] = *message++;
347  }
348 
349  /* i is always less than (sizeof msg), so: */
350  msg[i] = '\0';
351 
352  /* And this is the formatted message. It may be larger than
353  * PNG_MAX_ERROR_TEXT, but that is only used for 'chunk' errors and these
354  * are not (currently) formatted.
355  */
356  png_warning(png_ptr, msg);
357 }
358 #endif /* WARNINGS */
359 
360 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
361 void PNGAPI
363 {
364  if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
365  {
366 # ifdef PNG_READ_SUPPORTED
367  if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
368  png_ptr->chunk_name != 0)
369  png_chunk_warning(png_ptr, error_message);
370  else
371 # endif
372  png_warning(png_ptr, error_message);
373  }
374 
375  else
376  {
377 # ifdef PNG_READ_SUPPORTED
378  if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
379  png_ptr->chunk_name != 0)
380  png_chunk_error(png_ptr, error_message);
381  else
382 # endif
383  png_error(png_ptr, error_message);
384  }
385 
386 # ifndef PNG_ERROR_TEXT_SUPPORTED
387  PNG_UNUSED(error_message)
388 # endif
389 }
390 
391 void /* PRIVATE */
393 {
394  if ((png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) != 0)
395  png_warning(png_ptr, error_message);
396  else
397  png_error(png_ptr, error_message);
398 
399 # ifndef PNG_ERROR_TEXT_SUPPORTED
400  PNG_UNUSED(error_message)
401 # endif
402 }
403 
404 void /* PRIVATE */
406 {
407  if ((png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) != 0)
408  png_warning(png_ptr, error_message);
409  else
410  png_error(png_ptr, error_message);
411 
412 # ifndef PNG_ERROR_TEXT_SUPPORTED
413  PNG_UNUSED(error_message)
414 # endif
415 }
416 #endif /* BENIGN_ERRORS */
417 
418 #define PNG_MAX_ERROR_TEXT 196 /* Currently limited by profile_error in png.c */
419 #if defined(PNG_WARNINGS_SUPPORTED) || \
420  (defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED))
421 /* These utilities are used internally to build an error message that relates
422  * to the current chunk. The chunk name comes from png_ptr->chunk_name,
423  * which is used to prefix the message. The message is limited in length
424  * to 63 bytes. The name characters are output as hex digits wrapped in []
425  * if the character is invalid.
426  */
427 #define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
428 static PNG_CONST char png_digit[16] = {
429  '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
430  'A', 'B', 'C', 'D', 'E', 'F'
431 };
432 
433 static void /* PRIVATE */
435  error_message)
436 {
437  png_uint_32 chunk_name = png_ptr->chunk_name;
438  int iout = 0, ishift = 24;
439 
440  while (ishift >= 0)
441  {
442  int c = (int)(chunk_name >> ishift) & 0xff;
443 
444  ishift -= 8;
445  if (isnonalpha(c) != 0)
446  {
448  buffer[iout++] = png_digit[(c & 0xf0) >> 4];
449  buffer[iout++] = png_digit[c & 0x0f];
451  }
452 
453  else
454  {
455  buffer[iout++] = (char)c;
456  }
457  }
458 
459  if (error_message == NULL)
460  buffer[iout] = '\0';
461 
462  else
463  {
464  int iin = 0;
465 
466  buffer[iout++] = ':';
467  buffer[iout++] = ' ';
468 
469  while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0')
470  buffer[iout++] = error_message[iin++];
471 
472  /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */
473  buffer[iout] = '\0';
474  }
475 }
476 #endif /* WARNINGS || ERROR_TEXT */
477 
478 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
479 PNG_FUNCTION(void,PNGAPI
480 png_chunk_error,(png_const_structrp png_ptr, png_const_charp error_message),
482 {
483  char msg[18+PNG_MAX_ERROR_TEXT];
484  if (png_ptr == NULL)
485  png_error(png_ptr, error_message);
486 
487  else
488  {
489  png_format_buffer(png_ptr, msg, error_message);
490  png_error(png_ptr, msg);
491  }
492 }
493 #endif /* READ && ERROR_TEXT */
494 
495 #ifdef PNG_WARNINGS_SUPPORTED
496 void PNGAPI
498 {
499  char msg[18+PNG_MAX_ERROR_TEXT];
500  if (png_ptr == NULL)
501  png_warning(png_ptr, warning_message);
502 
503  else
504  {
505  png_format_buffer(png_ptr, msg, warning_message);
506  png_warning(png_ptr, msg);
507  }
508 }
509 #endif /* WARNINGS */
510 
511 #ifdef PNG_READ_SUPPORTED
512 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
513 void PNGAPI
515  error_message)
516 {
517  if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
518  png_chunk_warning(png_ptr, error_message);
519 
520  else
521  png_chunk_error(png_ptr, error_message);
522 
523 # ifndef PNG_ERROR_TEXT_SUPPORTED
524  PNG_UNUSED(error_message)
525 # endif
526 }
527 #endif
528 #endif /* READ */
529 
530 void /* PRIVATE */
532 {
533 # ifndef PNG_WARNINGS_SUPPORTED
534  PNG_UNUSED(message)
535 # endif
536 
537  /* This is always supported, but for just read or just write it
538  * unconditionally does the right thing.
539  */
540 # if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
541  if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
542 # endif
543 
544 # ifdef PNG_READ_SUPPORTED
545  {
546  if (error < PNG_CHUNK_ERROR)
547  png_chunk_warning(png_ptr, message);
548 
549  else
550  png_chunk_benign_error(png_ptr, message);
551  }
552 # endif
553 
554 # if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
555  else if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
556 # endif
557 
558 # ifdef PNG_WRITE_SUPPORTED
559  {
560  if (error < PNG_CHUNK_WRITE_ERROR)
561  png_app_warning(png_ptr, message);
562 
563  else
564  png_app_error(png_ptr, message);
565  }
566 # endif
567 }
568 
569 #ifdef PNG_ERROR_TEXT_SUPPORTED
570 #ifdef PNG_FLOATING_POINT_SUPPORTED
571 PNG_FUNCTION(void,
573 {
574 # define fixed_message "fixed point overflow in "
575 # define fixed_message_ln ((sizeof fixed_message)-1)
576  unsigned int iin;
579  iin = 0;
580  if (name != NULL)
581  while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
582  {
583  msg[fixed_message_ln + iin] = name[iin];
584  ++iin;
585  }
586  msg[fixed_message_ln + iin] = 0;
587  png_error(png_ptr, msg);
588 }
589 #endif
590 #endif
591 
592 #ifdef PNG_SETJMP_SUPPORTED
593 /* This API only exists if ANSI-C style error handling is used,
594  * otherwise it is necessary for png_default_error to be overridden.
595  */
596 jmp_buf* PNGAPI
598  size_t jmp_buf_size)
599 {
600  /* From libpng 1.6.0 the app gets one chance to set a 'jmpbuf_size' value
601  * and it must not change after that. Libpng doesn't care how big the
602  * buffer is, just that it doesn't change.
603  *
604  * If the buffer size is no *larger* than the size of jmp_buf when libpng is
605  * compiled a built in jmp_buf is returned; this preserves the pre-1.6.0
606  * semantics that this call will not fail. If the size is larger, however,
607  * the buffer is allocated and this may fail, causing the function to return
608  * NULL.
609  */
610  if (png_ptr == NULL)
611  return NULL;
612 
613  if (png_ptr->jmp_buf_ptr == NULL)
614  {
615  png_ptr->jmp_buf_size = 0; /* not allocated */
616 
617  if (jmp_buf_size <= (sizeof png_ptr->jmp_buf_local))
618  png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local;
619 
620  else
621  {
622  png_ptr->jmp_buf_ptr = png_voidcast(jmp_buf *,
623  png_malloc_warn(png_ptr, jmp_buf_size));
624 
625  if (png_ptr->jmp_buf_ptr == NULL)
626  return NULL; /* new NULL return on OOM */
627 
628  png_ptr->jmp_buf_size = jmp_buf_size;
629  }
630  }
631 
632  else /* Already allocated: check the size */
633  {
634  size_t size = png_ptr->jmp_buf_size;
635 
636  if (size == 0)
637  {
638  size = (sizeof png_ptr->jmp_buf_local);
639  if (png_ptr->jmp_buf_ptr != &png_ptr->jmp_buf_local)
640  {
641  /* This is an internal error in libpng: somehow we have been left
642  * with a stack allocated jmp_buf when the application regained
643  * control. It's always possible to fix this up, but for the moment
644  * this is a png_error because that makes it easy to detect.
645  */
646  png_error(png_ptr, "Libpng jmp_buf still allocated");
647  /* png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; */
648  }
649  }
650 
651  if (size != jmp_buf_size)
652  {
653  png_warning(png_ptr, "Application jmp_buf size changed");
654  return NULL; /* caller will probably crash: no choice here */
655  }
656  }
657 
658  /* Finally fill in the function, now we have a satisfactory buffer. It is
659  * valid to change the function on every call.
660  */
661  png_ptr->longjmp_fn = longjmp_fn;
662  return png_ptr->jmp_buf_ptr;
663 }
664 
665 void /* PRIVATE */
667 {
668  if (png_ptr != NULL)
669  {
670  jmp_buf *jb = png_ptr->jmp_buf_ptr;
671 
672  /* A size of 0 is used to indicate a local, stack, allocation of the
673  * pointer; used here and in png.c
674  */
675  if (jb != NULL && png_ptr->jmp_buf_size > 0)
676  {
677 
678  /* This stuff is so that a failure to free the error control structure
679  * does not leave libpng in a state with no valid error handling: the
680  * free always succeeds, if there is an error it gets ignored.
681  */
682  if (jb != &png_ptr->jmp_buf_local)
683  {
684  /* Make an internal, libpng, jmp_buf to return here */
685  jmp_buf free_jmp_buf;
686 
687  if (!setjmp(free_jmp_buf))
688  {
689  png_ptr->jmp_buf_ptr = &free_jmp_buf; /* come back here */
690  png_ptr->jmp_buf_size = 0; /* stack allocation */
691  png_ptr->longjmp_fn = longjmp;
692  png_free(png_ptr, jb); /* Return to setjmp on error */
693  }
694  }
695  }
696 
697  /* *Always* cancel everything out: */
698  png_ptr->jmp_buf_size = 0;
699  png_ptr->jmp_buf_ptr = NULL;
700  png_ptr->longjmp_fn = 0;
701  }
702 }
703 #endif
704 
705 /* This is the default error handling function. Note that replacements for
706  * this function MUST NOT RETURN, or the program will likely crash. This
707  * function is used by default, or if the program supplies NULL for the
708  * error function pointer in png_set_error_fn().
709  */
710 static PNG_FUNCTION(void /* PRIVATE */,
711 png_default_error,(png_const_structrp png_ptr, png_const_charp error_message),
713 {
714 #ifdef PNG_CONSOLE_IO_SUPPORTED
715 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
716  /* Check on NULL only added in 1.5.4 */
717  if (error_message != NULL && *error_message == PNG_LITERAL_SHARP)
718  {
719  /* Strip "#nnnn " from beginning of error message. */
720  int offset;
721  char error_number[16];
722  for (offset = 0; offset<15; offset++)
723  {
724  error_number[offset] = error_message[offset + 1];
725  if (error_message[offset] == ' ')
726  break;
727  }
728 
729  if ((offset > 1) && (offset < 15))
730  {
731  error_number[offset - 1] = '\0';
732  fprintf(stderr, "libpng error no. %s: %s",
733  error_number, error_message + offset + 1);
734  fprintf(stderr, PNG_STRING_NEWLINE);
735  }
736 
737  else
738  {
739  fprintf(stderr, "libpng error: %s, offset=%d",
740  error_message, offset);
741  fprintf(stderr, PNG_STRING_NEWLINE);
742  }
743  }
744  else
745 #endif
746  {
747  fprintf(stderr, "libpng error: %s", error_message ? error_message :
748  "undefined");
749  fprintf(stderr, PNG_STRING_NEWLINE);
750  }
751 #else
752  PNG_UNUSED(error_message) /* Make compiler happy */
753 #endif
754  png_longjmp(png_ptr, 1);
755 }
756 
757 PNG_FUNCTION(void,PNGAPI
759 {
760 #ifdef PNG_SETJMP_SUPPORTED
761  if (png_ptr != NULL && png_ptr->longjmp_fn != NULL &&
762  png_ptr->jmp_buf_ptr != NULL)
763  png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val);
764 #else
765  PNG_UNUSED(png_ptr)
766  PNG_UNUSED(val)
767 #endif
768 
769  /* If control reaches this point, png_longjmp() must not return. The only
770  * choice is to terminate the whole process (or maybe the thread); to do
771  * this the ANSI-C abort() function is used unless a different method is
772  * implemented by overriding the default configuration setting for
773  * PNG_ABORT().
774  */
775  PNG_ABORT();
776 }
777 
778 #ifdef PNG_WARNINGS_SUPPORTED
779 /* This function is called when there is a warning, but the library thinks
780  * it can continue anyway. Replacement functions don't have to do anything
781  * here if you don't want them to. In the default configuration, png_ptr is
782  * not used, but it is passed in case it may be useful.
783  */
784 static void /* PRIVATE */
786 {
787 #ifdef PNG_CONSOLE_IO_SUPPORTED
788 # ifdef PNG_ERROR_NUMBERS_SUPPORTED
789  if (*warning_message == PNG_LITERAL_SHARP)
790  {
791  int offset;
792  char warning_number[16];
793  for (offset = 0; offset < 15; offset++)
794  {
795  warning_number[offset] = warning_message[offset + 1];
796  if (warning_message[offset] == ' ')
797  break;
798  }
799 
800  if ((offset > 1) && (offset < 15))
801  {
802  warning_number[offset + 1] = '\0';
803  fprintf(stderr, "libpng warning no. %s: %s",
804  warning_number, warning_message + offset);
805  fprintf(stderr, PNG_STRING_NEWLINE);
806  }
807 
808  else
809  {
810  fprintf(stderr, "libpng warning: %s",
811  warning_message);
812  fprintf(stderr, PNG_STRING_NEWLINE);
813  }
814  }
815  else
816 # endif
817 
818  {
819  fprintf(stderr, "libpng warning: %s", warning_message);
820  fprintf(stderr, PNG_STRING_NEWLINE);
821  }
822 #else
823  PNG_UNUSED(warning_message) /* Make compiler happy */
824 #endif
825  PNG_UNUSED(png_ptr) /* Make compiler happy */
826 }
827 #endif /* WARNINGS */
828 
829 /* This function is called when the application wants to use another method
830  * of handling errors and warnings. Note that the error function MUST NOT
831  * return to the calling routine or serious problems will occur. The return
832  * method used in the default routine calls longjmp(png_ptr->jmp_buf_ptr, 1)
833  */
834 void PNGAPI
836  png_error_ptr error_fn, png_error_ptr warning_fn)
837 {
838  if (png_ptr == NULL)
839  return;
840 
841  png_ptr->error_ptr = error_ptr;
842  png_ptr->error_fn = error_fn;
843 #ifdef PNG_WARNINGS_SUPPORTED
844  png_ptr->warning_fn = warning_fn;
845 #else
846  PNG_UNUSED(warning_fn)
847 #endif
848 }
849 
850 
851 /* This function returns a pointer to the error_ptr associated with the user
852  * functions. The application should free any memory associated with this
853  * pointer before png_write_destroy and png_read_destroy are called.
854  */
857 {
858  if (png_ptr == NULL)
859  return NULL;
860 
861  return ((png_voidp)png_ptr->error_ptr);
862 }
863 
864 
865 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
866 void PNGAPI
867 png_set_strip_error_numbers(png_structrp png_ptr, png_uint_32 strip_mode)
868 {
869  if (png_ptr != NULL)
870  {
871  png_ptr->flags &=
873  PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
874  }
875 }
876 #endif
877 
878 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
879  defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
880  /* Currently the above both depend on SETJMP_SUPPORTED, however it would be
881  * possible to implement without setjmp support just so long as there is some
882  * way to handle the error return here:
883  */
884 PNG_FUNCTION(void /* PRIVATE */, (PNGCBAPI
885 png_safe_error),(png_structp png_nonconst_ptr, png_const_charp error_message),
886  PNG_NORETURN)
887 {
888  const png_const_structrp png_ptr = png_nonconst_ptr;
889  png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr);
890 
891  /* An error is always logged here, overwriting anything (typically a warning)
892  * that is already there:
893  */
894  if (image != NULL)
895  {
896  png_safecat(image->message, (sizeof image->message), 0, error_message);
897  image->warning_or_error |= PNG_IMAGE_ERROR;
898 
899  /* Retrieve the jmp_buf from within the png_control, making this work for
900  * C++ compilation too is pretty tricky: C++ wants a pointer to the first
901  * element of a jmp_buf, but C doesn't tell us the type of that.
902  */
903  if (image->opaque != NULL && image->opaque->error_buf != NULL)
904  longjmp(png_control_jmp_buf(image->opaque), 1);
905 
906  /* Missing longjmp buffer, the following is to help debugging: */
907  {
908  size_t pos = png_safecat(image->message, (sizeof image->message), 0,
909  "bad longjmp: ");
910  png_safecat(image->message, (sizeof image->message), pos,
911  error_message);
912  }
913  }
914 
915  /* Here on an internal programming error. */
916  abort();
917 }
918 
919 #ifdef PNG_WARNINGS_SUPPORTED
920 void /* PRIVATE */ PNGCBAPI
921 png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message)
922 {
923  const png_const_structrp png_ptr = png_nonconst_ptr;
924  png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr);
925 
926  /* A warning is only logged if there is no prior warning or error. */
927  if (image->warning_or_error == 0)
928  {
929  png_safecat(image->message, (sizeof image->message), 0, warning_message);
930  image->warning_or_error |= PNG_IMAGE_WARNING;
931  }
932 }
933 #endif
934 
935 int /* PRIVATE */
936 png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg)
937 {
938  volatile png_imagep image = image_in;
939  volatile int result;
940  volatile png_voidp saved_error_buf;
941  jmp_buf safe_jmpbuf;
942 
943  /* Safely execute function(arg) with png_error returning to this function. */
944  saved_error_buf = image->opaque->error_buf;
945  result = setjmp(safe_jmpbuf) == 0;
946 
947  if (result != 0)
948  {
949 
950  image->opaque->error_buf = safe_jmpbuf;
951  result = function(arg);
952  }
953 
954  image->opaque->error_buf = saved_error_buf;
955 
956  /* And do the cleanup prior to any failure return. */
957  if (result == 0)
958  png_image_free(image);
959 
960  return result;
961 }
962 #endif /* SIMPLIFIED READ || SIMPLIFIED_WRITE */
963 #endif /* READ || WRITE */
PNG_FORMAT_NUMBER
#define PNG_FORMAT_NUMBER(buffer, format, number)
Definition: pngpriv.h:1739
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#define fixed_message_ln
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#define PNG_NORETURN
Definition: pngconf.h:442
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#define PNG_FLAG_STRIP_ERROR_NUMBERS
Definition: pngpriv.h:688
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#define PNG_UNUSED(param)
Definition: pngpriv.h:429
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Definition: pngstruct.h:155
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void png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
Definition: pngerror.c:514
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Definition: pngerror.c:362
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png_const_charp msg
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Definition: pngconf.h:582
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#define PNG_FLAG_APP_WARNINGS_WARN
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void png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message)
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#define PNGCBAPI
Definition: pngconf.h:264
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Definition: png.h:859
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#define PNG_IS_READ_STRUCT
Definition: pngpriv.h:630
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Definition: pngerror.c:856
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#define PNG_FLAG_STRIP_ERROR_TEXT
Definition: pngpriv.h:689
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#define PNG_WARNING_PARAMETER_COUNT
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#define PNG_NUMBER_BUFFER_SIZE
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#define png_control_jmp_buf(pc)
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#define PNG_NUMBER_FORMAT_02x
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