2 /* pngerror.c - stub functions for i/o and memory allocation
4 * Last changed in libpng 1.6.0 [February 14, 2013]
5 * Copyright (c) 1998-2013 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.)
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
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
21 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
23 static PNG_FUNCTION(void, png_default_error,PNGARG((png_const_structrp png_ptr,
24 png_const_charp error_message)),PNG_NORETURN);
26 #ifdef PNG_WARNINGS_SUPPORTED
27 static void /* PRIVATE */
28 png_default_warning PNGARG((png_const_structrp png_ptr,
29 png_const_charp warning_message));
30 #endif /* PNG_WARNINGS_SUPPORTED */
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.
37 #ifdef PNG_ERROR_TEXT_SUPPORTED
38 PNG_FUNCTION(void,PNGAPI
39 png_error,(png_const_structrp png_ptr, png_const_charp error_message),
42 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
47 (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
49 if (*error_message == PNG_LITERAL_SHARP)
51 /* Strip "#nnnn " from beginning of error message. */
53 for (offset = 1; offset<15; offset++)
54 if (error_message[offset] == ' ')
57 if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
60 for (i = 0; i < offset - 1; i++)
61 msg[i] = error_message[i + 1];
67 error_message += offset;
72 if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
82 if (png_ptr != NULL && png_ptr->error_fn != NULL)
83 (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr),
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);
91 PNG_FUNCTION(void,PNGAPI
92 png_err,(png_const_structrp png_ptr),PNG_NORETURN)
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.
99 if (png_ptr != NULL && png_ptr->error_fn != NULL)
100 (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), "");
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, "");
106 #endif /* PNG_ERROR_TEXT_SUPPORTED */
108 /* Utility to safely appends strings to a buffer. This never errors out so
109 * error checking is not required in the caller.
112 png_safecat(png_charp buffer, size_t bufsize, size_t pos,
113 png_const_charp string)
115 if (buffer != NULL && pos < bufsize)
118 while (*string != '\0' && pos < bufsize-1)
119 buffer[pos++] = *string++;
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.
133 png_format_number(png_const_charp start, png_charp end, int format,
134 png_alloc_size_t number)
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) */
142 /* This is written so that the loop always runs at least once, even with
145 while (end > start && (number != 0 || count < mincount))
148 static const char digits[] = "0123456789ABCDEF";
152 case PNG_NUMBER_FORMAT_fixed:
153 /* Needs five digits (the fraction) */
155 if (output || number % 10 != 0)
157 *--end = digits[number % 10];
163 case PNG_NUMBER_FORMAT_02u:
164 /* Expects at least 2 digits. */
168 case PNG_NUMBER_FORMAT_u:
169 *--end = digits[number % 10];
173 case PNG_NUMBER_FORMAT_02x:
174 /* This format expects at least two digits */
178 case PNG_NUMBER_FORMAT_x:
179 *--end = digits[number & 0xf];
183 default: /* an error */
188 /* Keep track of the number of digits added */
191 /* Float a fixed number here: */
192 if (format == PNG_NUMBER_FORMAT_fixed) if (count == 5) if (end > start)
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
200 else if (number == 0) /* and !output */
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.
216 png_warning(png_const_structrp png_ptr, png_const_charp warning_message)
221 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
223 (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
226 if (*warning_message == PNG_LITERAL_SHARP)
228 for (offset = 1; offset < 15; offset++)
229 if (warning_message[offset] == ' ')
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);
238 png_default_warning(png_ptr, warning_message + offset);
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.
247 png_warning_parameter(png_warning_parameters p, int number,
248 png_const_charp string)
250 if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT)
251 (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string);
255 png_warning_parameter_unsigned(png_warning_parameters p, int number, int format,
256 png_alloc_size_t value)
258 char buffer[PNG_NUMBER_BUFFER_SIZE];
259 png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value));
263 png_warning_parameter_signed(png_warning_parameters p, int number, int format,
268 char buffer[PNG_NUMBER_BUFFER_SIZE];
270 /* Avoid overflow by doing the negate in a png_alloc_size_t: */
271 u = (png_alloc_size_t)value;
275 str = PNG_FORMAT_NUMBER(buffer, format, u);
277 if (value < 0 && str > buffer)
280 png_warning_parameter(p, number, str);
284 png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p,
285 png_const_charp message)
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.
292 size_t i = 0; /* Index in the msg[] buffer: */
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.
301 while (i<(sizeof msg)-1 && *message != '\0')
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 @.
306 if (p != NULL && *message == '@' && message[1] != '\0')
308 int parameter_char = *++message; /* Consume the '@' */
309 static const char valid_parameters[] = "123456789";
312 /* Search for the parameter digit, the index in the string is the
315 while (valid_parameters[parameter] != parameter_char &&
316 valid_parameters[parameter] != '\0')
319 /* If the parameter digit is out of range it will just get printed. */
320 if (parameter < PNG_WARNING_PARAMETER_COUNT)
322 /* Append this parameter */
323 png_const_charp parm = p[parameter];
324 png_const_charp pend = p[parameter] + (sizeof p[parameter]);
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
330 while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend)
333 /* Consume the parameter digit too: */
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.
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.
346 msg[i++] = *message++;
349 /* i is always less than (sizeof msg), so: */
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.
356 png_warning(png_ptr, msg);
358 #endif /* PNG_WARNINGS_SUPPORTED */
360 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
362 png_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
364 if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
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);
372 png_warning(png_ptr, error_message);
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);
383 png_error(png_ptr, error_message);
388 png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
390 if (png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN)
391 png_warning(png_ptr, error_message);
393 png_error(png_ptr, error_message);
397 png_app_error(png_const_structrp png_ptr, png_const_charp error_message)
399 if (png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN)
400 png_warning(png_ptr, error_message);
402 png_error(png_ptr, error_message);
404 #endif /* BENIGN_ERRORS */
406 /* These utilities are used internally to build an error message that relates
407 * to the current chunk. The chunk name comes from png_ptr->chunk_name,
408 * this is used to prefix the message. The message is limited in length
409 * to 63 bytes, the name characters are output as hex digits wrapped in []
410 * if the character is invalid.
412 #define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
413 static PNG_CONST char png_digit[16] = {
414 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
415 'A', 'B', 'C', 'D', 'E', 'F'
418 #define PNG_MAX_ERROR_TEXT 196 /* Currently limited be profile_error in png.c */
419 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
420 static void /* PRIVATE */
421 png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
424 png_uint_32 chunk_name = png_ptr->chunk_name;
425 int iout = 0, ishift = 24;
429 int c = (int)(chunk_name >> ishift) & 0xff;
434 buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
435 buffer[iout++] = png_digit[(c & 0xf0) >> 4];
436 buffer[iout++] = png_digit[c & 0x0f];
437 buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET;
442 buffer[iout++] = (char)c;
446 if (error_message == NULL)
453 buffer[iout++] = ':';
454 buffer[iout++] = ' ';
456 while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0')
457 buffer[iout++] = error_message[iin++];
459 /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */
463 #endif /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */
465 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
466 PNG_FUNCTION(void,PNGAPI
467 png_chunk_error,(png_const_structrp png_ptr, png_const_charp error_message),
470 char msg[18+PNG_MAX_ERROR_TEXT];
472 png_error(png_ptr, error_message);
476 png_format_buffer(png_ptr, msg, error_message);
477 png_error(png_ptr, msg);
480 #endif /* PNG_READ_SUPPORTED && PNG_ERROR_TEXT_SUPPORTED */
482 #ifdef PNG_WARNINGS_SUPPORTED
484 png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message)
486 char msg[18+PNG_MAX_ERROR_TEXT];
488 png_warning(png_ptr, warning_message);
492 png_format_buffer(png_ptr, msg, warning_message);
493 png_warning(png_ptr, msg);
496 #endif /* PNG_WARNINGS_SUPPORTED */
498 #ifdef PNG_READ_SUPPORTED
499 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
501 png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp
504 if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
505 png_chunk_warning(png_ptr, error_message);
508 png_chunk_error(png_ptr, error_message);
511 #endif /* PNG_READ_SUPPORTED */
514 png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
516 /* This is always supported, but for just read or just write it
517 * unconditionally does the right thing.
519 # if (defined PNG_READ_SUPPORTED) && (defined PNG_WRITE_SUPPORTED)
520 if (png_ptr->mode & PNG_IS_READ_STRUCT)
523 # ifdef PNG_READ_SUPPORTED
525 if (error < PNG_CHUNK_ERROR)
526 png_chunk_warning(png_ptr, message);
529 png_chunk_benign_error(png_ptr, message);
533 # if (defined PNG_READ_SUPPORTED) && (defined PNG_WRITE_SUPPORTED)
534 else if (!(png_ptr->mode & PNG_IS_READ_STRUCT))
537 # ifdef PNG_WRITE_SUPPORTED
539 if (error < PNG_CHUNK_WRITE_ERROR)
540 png_app_warning(png_ptr, message);
543 png_app_error(png_ptr, message);
548 #ifdef PNG_ERROR_TEXT_SUPPORTED
549 #ifdef PNG_FLOATING_POINT_SUPPORTED
551 png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN)
553 # define fixed_message "fixed point overflow in "
554 # define fixed_message_ln ((sizeof fixed_message)-1)
556 char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT];
557 memcpy(msg, fixed_message, fixed_message_ln);
559 if (name != NULL) while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
561 msg[fixed_message_ln + iin] = name[iin];
564 msg[fixed_message_ln + iin] = 0;
565 png_error(png_ptr, msg);
570 #ifdef PNG_SETJMP_SUPPORTED
571 /* This API only exists if ANSI-C style error handling is used,
572 * otherwise it is necessary for png_default_error to be overridden.
575 png_set_longjmp_fn(png_structrp png_ptr, png_longjmp_ptr longjmp_fn,
578 /* From libpng 1.6.0 the app gets one chance to set a 'jmpbuf_size' value
579 * and it must not change after that. Libpng doesn't care how big the
580 * buffer is, just that it doesn't change.
582 * If the buffer size is no *larger* than the size of jmp_buf when libpng is
583 * compiled a built in jmp_buf is returned; this preserves the pre-1.6.0
584 * semantics that this call will not fail. If the size is larger, however,
585 * the buffer is allocated and this may fail, causing the function to return
591 if (png_ptr->jmp_buf_ptr == NULL)
593 png_ptr->jmp_buf_size = 0; /* not allocated */
595 if (jmp_buf_size <= (sizeof png_ptr->jmp_buf_local))
596 png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local;
600 png_ptr->jmp_buf_ptr = png_voidcast(jmp_buf *,
601 png_malloc_warn(png_ptr, jmp_buf_size));
603 if (png_ptr->jmp_buf_ptr == NULL)
604 return NULL; /* new NULL return on OOM */
606 png_ptr->jmp_buf_size = jmp_buf_size;
610 else /* Already allocated: check the size */
612 size_t size = png_ptr->jmp_buf_size;
616 size = (sizeof png_ptr->jmp_buf_local);
617 if (png_ptr->jmp_buf_ptr != &png_ptr->jmp_buf_local)
619 /* This is an internal error in libpng: somehow we have been left
620 * with a stack allocated jmp_buf when the application regained
621 * control. It's always possible to fix this up, but for the moment
622 * this is a png_error because that makes it easy to detect.
624 png_error(png_ptr, "Libpng jmp_buf still allocated");
625 /* png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; */
629 if (size != jmp_buf_size)
631 png_warning(png_ptr, "Application jmp_buf size changed");
632 return NULL; /* caller will probably crash: no choice here */
636 /* Finally fill in the function, now we have a satisfactory buffer. It is
637 * valid to change the function on every call.
639 png_ptr->longjmp_fn = longjmp_fn;
640 return png_ptr->jmp_buf_ptr;
644 png_free_jmpbuf(png_structrp png_ptr)
648 jmp_buf *jb = png_ptr->jmp_buf_ptr;
650 /* A size of 0 is used to indicate a local, stack, allocation of the
651 * pointer; used here and in png.c
653 if (jb != NULL && png_ptr->jmp_buf_size > 0)
656 /* This stuff is so that a failure to free the error control structure
657 * does not leave libpng in a state with no valid error handling: the
658 * free always succeeds, if there is an error it gets ignored.
660 if (jb != &png_ptr->jmp_buf_local)
662 /* Make an internal, libpng, jmp_buf to return here */
663 jmp_buf free_jmp_buf;
665 if (!setjmp(free_jmp_buf))
667 png_ptr->jmp_buf_ptr = &free_jmp_buf; /* come back here */
668 png_ptr->jmp_buf_size = 0; /* stack allocation */
669 png_ptr->longjmp_fn = longjmp;
670 png_free(png_ptr, jb); /* Return to setjmp on error */
675 /* *Always* cancel everything out: */
676 png_ptr->jmp_buf_size = 0;
677 png_ptr->jmp_buf_ptr = NULL;
678 png_ptr->longjmp_fn = 0;
683 /* This is the default error handling function. Note that replacements for
684 * this function MUST NOT RETURN, or the program will likely crash. This
685 * function is used by default, or if the program supplies NULL for the
686 * error function pointer in png_set_error_fn().
688 static PNG_FUNCTION(void /* PRIVATE */,
689 png_default_error,(png_const_structrp png_ptr, png_const_charp error_message),
692 #ifdef PNG_CONSOLE_IO_SUPPORTED
693 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
694 /* Check on NULL only added in 1.5.4 */
695 if (error_message != NULL && *error_message == PNG_LITERAL_SHARP)
697 /* Strip "#nnnn " from beginning of error message. */
699 char error_number[16];
700 for (offset = 0; offset<15; offset++)
702 error_number[offset] = error_message[offset + 1];
703 if (error_message[offset] == ' ')
707 if ((offset > 1) && (offset < 15))
709 error_number[offset - 1] = '\0';
710 fprintf(stderr, "libpng error no. %s: %s",
711 error_number, error_message + offset + 1);
712 fprintf(stderr, PNG_STRING_NEWLINE);
717 fprintf(stderr, "libpng error: %s, offset=%d",
718 error_message, offset);
719 fprintf(stderr, PNG_STRING_NEWLINE);
725 fprintf(stderr, "libpng error: %s", error_message ? error_message :
727 fprintf(stderr, PNG_STRING_NEWLINE);
730 PNG_UNUSED(error_message) /* Make compiler happy */
732 png_longjmp(png_ptr, 1);
735 PNG_FUNCTION(void,PNGAPI
736 png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN)
738 #ifdef PNG_SETJMP_SUPPORTED
739 if (png_ptr && png_ptr->longjmp_fn && png_ptr->jmp_buf_ptr)
740 png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val);
743 /* Here if not setjmp support or if png_ptr is null. */
747 #ifdef PNG_WARNINGS_SUPPORTED
748 /* This function is called when there is a warning, but the library thinks
749 * it can continue anyway. Replacement functions don't have to do anything
750 * here if you don't want them to. In the default configuration, png_ptr is
751 * not used, but it is passed in case it may be useful.
753 static void /* PRIVATE */
754 png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message)
756 #ifdef PNG_CONSOLE_IO_SUPPORTED
757 # ifdef PNG_ERROR_NUMBERS_SUPPORTED
758 if (*warning_message == PNG_LITERAL_SHARP)
761 char warning_number[16];
762 for (offset = 0; offset < 15; offset++)
764 warning_number[offset] = warning_message[offset + 1];
765 if (warning_message[offset] == ' ')
769 if ((offset > 1) && (offset < 15))
771 warning_number[offset + 1] = '\0';
772 fprintf(stderr, "libpng warning no. %s: %s",
773 warning_number, warning_message + offset);
774 fprintf(stderr, PNG_STRING_NEWLINE);
779 fprintf(stderr, "libpng warning: %s",
781 fprintf(stderr, PNG_STRING_NEWLINE);
788 fprintf(stderr, "libpng warning: %s", warning_message);
789 fprintf(stderr, PNG_STRING_NEWLINE);
792 PNG_UNUSED(warning_message) /* Make compiler happy */
794 PNG_UNUSED(png_ptr) /* Make compiler happy */
796 #endif /* PNG_WARNINGS_SUPPORTED */
798 /* This function is called when the application wants to use another method
799 * of handling errors and warnings. Note that the error function MUST NOT
800 * return to the calling routine or serious problems will occur. The return
801 * method used in the default routine calls longjmp(png_ptr->jmp_buf_ptr, 1)
804 png_set_error_fn(png_structrp png_ptr, png_voidp error_ptr,
805 png_error_ptr error_fn, png_error_ptr warning_fn)
810 png_ptr->error_ptr = error_ptr;
811 png_ptr->error_fn = error_fn;
812 #ifdef PNG_WARNINGS_SUPPORTED
813 png_ptr->warning_fn = warning_fn;
815 PNG_UNUSED(warning_fn)
820 /* This function returns a pointer to the error_ptr associated with the user
821 * functions. The application should free any memory associated with this
822 * pointer before png_write_destroy and png_read_destroy are called.
825 png_get_error_ptr(png_const_structrp png_ptr)
830 return ((png_voidp)png_ptr->error_ptr);
834 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
836 png_set_strip_error_numbers(png_structrp png_ptr, png_uint_32 strip_mode)
841 ((~(PNG_FLAG_STRIP_ERROR_NUMBERS |
842 PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
847 #if defined PNG_SIMPLIFIED_READ_SUPPORTED ||\
848 defined PNG_SIMPLIFIED_WRITE_SUPPORTED
849 /* Currently the above both depend on SETJMP_SUPPORTED, however it would be
850 * possible to implement without setjmp support just so long as there is some
851 * way to handle the error return here:
853 PNG_FUNCTION(void /* PRIVATE */,
854 png_safe_error,(png_structp png_nonconst_ptr, png_const_charp error_message),
857 const png_const_structrp png_ptr = png_nonconst_ptr;
858 png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr);
860 /* An error is always logged here, overwriting anything (typically a warning)
861 * that is already there:
865 png_safecat(image->message, (sizeof image->message), 0, error_message);
866 image->warning_or_error |= PNG_IMAGE_ERROR;
868 /* Retrieve the jmp_buf from within the png_control, making this work for
869 * C++ compilation too is pretty tricky: C++ wants a pointer to the first
870 * element of a jmp_buf, but C doesn't tell us the type of that.
872 if (image->opaque != NULL && image->opaque->error_buf != NULL)
873 longjmp(png_control_jmp_buf(image->opaque), 1);
875 /* Missing longjmp buffer, the following is to help debugging: */
877 size_t pos = png_safecat(image->message, (sizeof image->message), 0,
879 png_safecat(image->message, (sizeof image->message), pos,
884 /* Here on an internal programming error. */
888 #ifdef PNG_WARNINGS_SUPPORTED
890 png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message)
892 const png_const_structrp png_ptr = png_nonconst_ptr;
893 png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr);
895 /* A warning is only logged if there is no prior warning or error. */
896 if (image->warning_or_error == 0)
898 png_safecat(image->message, (sizeof image->message), 0, warning_message);
899 image->warning_or_error |= PNG_IMAGE_WARNING;
905 png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg)
907 volatile png_imagep image = image_in;
909 volatile png_voidp saved_error_buf;
912 /* Safely execute function(arg) with png_error returning to this function. */
913 saved_error_buf = image->opaque->error_buf;
914 result = setjmp(safe_jmpbuf) == 0;
919 image->opaque->error_buf = safe_jmpbuf;
920 result = function(arg);
923 image->opaque->error_buf = saved_error_buf;
925 /* And do the cleanup prior to any failure return. */
927 png_image_free(image);
931 #endif /* SIMPLIFIED READ/WRITE */
932 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */