pngerror.c revision 76d05dc695b06c4e987bb8078f78032441e1430c 
1
2/* pngerror.c - stub functions for i/o and memory allocation
3 *
4 * Last changed in libpng 1.2.41 [December 3, 2009]
5 * Copyright (c) 1998-2009 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#define PNG_INTERNAL
20#define PNG_NO_PEDANTIC_WARNINGS
21#include "png.h"
22#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
23
24static void /* PRIVATE */
25png_default_error PNGARG((png_structp png_ptr,
26  png_const_charp error_message)) PNG_NORETURN;
27#ifdef PNG_WARNINGS_SUPPORTED
28static void /* PRIVATE */
29png_default_warning PNGARG((png_structp png_ptr,
30  png_const_charp warning_message));
31#endif /* PNG_WARNINGS_SUPPORTED */
32
33/* This function is called whenever there is a fatal error.  This function
34 * should not be changed.  If there is a need to handle errors differently,
35 * you should supply a replacement error function and use png_set_error_fn()
36 * to replace the error function at run-time.
37 */
38#ifdef PNG_ERROR_TEXT_SUPPORTED
39void PNGAPI
40png_error(png_structp 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&
47       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
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           if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
57           {
58              int i;
59              for (i = 0; i < offset - 1; i++)
60                 msg[i] = error_message[i + 1];
61              msg[i - 1] = '\0';
62              error_message = msg;
63           }
64           else
65              error_message += offset;
66       }
67       else
68       {
69           if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
70           {
71              msg[0] = '0';
72              msg[1] = '\0';
73              error_message = msg;
74           }
75       }
76     }
77   }
78#endif
79   if (png_ptr != NULL && png_ptr->error_fn != NULL)
80      (*(png_ptr->error_fn))(png_ptr, error_message);
81
82   /* If the custom handler doesn't exist, or if it returns,
83      use the default handler, which will not return. */
84   png_default_error(png_ptr, error_message);
85}
86#else
87void PNGAPI
88png_err(png_structp png_ptr)
89{
90   if (png_ptr != NULL && png_ptr->error_fn != NULL)
91      (*(png_ptr->error_fn))(png_ptr, '\0');
92
93   /* If the custom handler doesn't exist, or if it returns,
94      use the default handler, which will not return. */
95   png_default_error(png_ptr, '\0');
96}
97#endif /* PNG_ERROR_TEXT_SUPPORTED */
98
99#ifdef PNG_WARNINGS_SUPPORTED
100/* This function is called whenever there is a non-fatal error.  This function
101 * should not be changed.  If there is a need to handle warnings differently,
102 * you should supply a replacement warning function and use
103 * png_set_error_fn() to replace the warning function at run-time.
104 */
105void PNGAPI
106png_warning(png_structp png_ptr, png_const_charp warning_message)
107{
108   int offset = 0;
109   if (png_ptr != NULL)
110   {
111#ifdef PNG_ERROR_NUMBERS_SUPPORTED
112   if (png_ptr->flags&
113     (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
114#endif
115     {
116       if (*warning_message == PNG_LITERAL_SHARP)
117       {
118           for (offset = 1; offset < 15; offset++)
119              if (warning_message[offset] == ' ')
120                  break;
121       }
122     }
123   }
124   if (png_ptr != NULL && png_ptr->warning_fn != NULL)
125      (*(png_ptr->warning_fn))(png_ptr, warning_message + offset);
126   else
127      png_default_warning(png_ptr, warning_message + offset);
128}
129#endif /* PNG_WARNINGS_SUPPORTED */
130
131#ifdef PNG_BENIGN_ERRORS_SUPPORTED
132void PNGAPI
133png_benign_error(png_structp png_ptr, png_const_charp error_message)
134{
135  if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
136    png_warning(png_ptr, error_message);
137  else
138    png_error(png_ptr, error_message);
139}
140#endif
141
142/* These utilities are used internally to build an error message that relates
143 * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
144 * this is used to prefix the message.  The message is limited in length
145 * to 63 bytes, the name characters are output as hex digits wrapped in []
146 * if the character is invalid.
147 */
148#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
149static PNG_CONST char png_digit[16] = {
150   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
151   'A', 'B', 'C', 'D', 'E', 'F'
152};
153
154#define PNG_MAX_ERROR_TEXT 64
155#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
156static void /* PRIVATE */
157png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp
158   error_message)
159{
160   int iout = 0, iin = 0;
161
162   while (iin < 4)
163   {
164      int c = png_ptr->chunk_name[iin++];
165      if (isnonalpha(c))
166      {
167         buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
168         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
169         buffer[iout++] = png_digit[c & 0x0f];
170         buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET;
171      }
172      else
173      {
174         buffer[iout++] = (png_byte)c;
175      }
176   }
177
178   if (error_message == NULL)
179      buffer[iout] = '\0';
180   else
181   {
182      buffer[iout++] = ':';
183      buffer[iout++] = ' ';
184      png_memcpy(buffer + iout, error_message, PNG_MAX_ERROR_TEXT);
185      buffer[iout + PNG_MAX_ERROR_TEXT - 1] = '\0';
186   }
187}
188
189#ifdef PNG_READ_SUPPORTED
190void PNGAPI
191png_chunk_error(png_structp png_ptr, png_const_charp error_message)
192{
193   char msg[18+PNG_MAX_ERROR_TEXT];
194   if (png_ptr == NULL)
195     png_error(png_ptr, error_message);
196   else
197   {
198     png_format_buffer(png_ptr, msg, error_message);
199     png_error(png_ptr, msg);
200   }
201}
202#endif /* PNG_READ_SUPPORTED */
203#endif /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */
204
205#ifdef PNG_WARNINGS_SUPPORTED
206void PNGAPI
207png_chunk_warning(png_structp png_ptr, png_const_charp warning_message)
208{
209   char msg[18+PNG_MAX_ERROR_TEXT];
210   if (png_ptr == NULL)
211     png_warning(png_ptr, warning_message);
212   else
213   {
214     png_format_buffer(png_ptr, msg, warning_message);
215     png_warning(png_ptr, msg);
216   }
217}
218#endif /* PNG_WARNINGS_SUPPORTED */
219
220#ifdef PNG_READ_SUPPORTED
221#ifdef PNG_BENIGN_ERRORS_SUPPORTED
222void PNGAPI
223png_chunk_benign_error(png_structp png_ptr, png_const_charp error_message)
224{
225  if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
226    png_chunk_warning(png_ptr, error_message);
227  else
228    png_chunk_error(png_ptr, error_message);
229}
230#endif
231#endif /* PNG_READ_SUPPORTED */
232
233/* This is the default error handling function.  Note that replacements for
234 * this function MUST NOT RETURN, or the program will likely crash.  This
235 * function is used by default, or if the program supplies NULL for the
236 * error function pointer in png_set_error_fn().
237 */
238static void /* PRIVATE */
239png_default_error(png_structp png_ptr, png_const_charp error_message)
240{
241#ifdef PNG_CONSOLE_IO_SUPPORTED
242#ifdef PNG_ERROR_NUMBERS_SUPPORTED
243   if (*error_message == PNG_LITERAL_SHARP)
244   {
245     /* Strip "#nnnn " from beginning of error message. */
246     int offset;
247     char error_number[16];
248     for (offset = 0; offset<15; offset++)
249     {
250         error_number[offset] = error_message[offset + 1];
251         if (error_message[offset] == ' ')
252             break;
253     }
254     if ((offset > 1) && (offset < 15))
255     {
256       error_number[offset - 1] = '\0';
257       fprintf(stderr, "libpng error no. %s: %s",
258          error_number, error_message + offset + 1);
259       fprintf(stderr, PNG_STRING_NEWLINE);
260     }
261     else
262     {
263       fprintf(stderr, "libpng error: %s, offset=%d",
264          error_message, offset);
265       fprintf(stderr, PNG_STRING_NEWLINE);
266     }
267   }
268   else
269#endif
270   {
271      fprintf(stderr, "libpng error: %s", error_message);
272      fprintf(stderr, PNG_STRING_NEWLINE);
273   }
274#endif
275
276#ifdef PNG_SETJMP_SUPPORTED
277   if (png_ptr)
278   {
279#  ifdef USE_FAR_KEYWORD
280   {
281      jmp_buf jmpbuf;
282      png_memcpy(jmpbuf, png_ptr->jmpbuf, png_sizeof(jmp_buf));
283     longjmp(jmpbuf,1);
284   }
285#  else
286   longjmp(png_ptr->jmpbuf, 1);
287#  endif
288   }
289#endif
290   /* Here if not setjmp support or if png_ptr is null. */
291   PNG_ABORT();
292#ifndef PNG_CONSOLE_IO_SUPPORTED
293   error_message = error_message; /* Make compiler happy */
294#endif
295}
296
297#ifdef PNG_WARNINGS_SUPPORTED
298/* This function is called when there is a warning, but the library thinks
299 * it can continue anyway.  Replacement functions don't have to do anything
300 * here if you don't want them to.  In the default configuration, png_ptr is
301 * not used, but it is passed in case it may be useful.
302 */
303static void /* PRIVATE */
304png_default_warning(png_structp png_ptr, png_const_charp warning_message)
305{
306#ifdef PNG_CONSOLE_IO_SUPPORTED
307#  ifdef PNG_ERROR_NUMBERS_SUPPORTED
308   if (*warning_message == PNG_LITERAL_SHARP)
309   {
310     int offset;
311     char warning_number[16];
312     for (offset = 0; offset < 15; offset++)
313     {
314        warning_number[offset] = warning_message[offset + 1];
315        if (warning_message[offset] == ' ')
316            break;
317     }
318     if ((offset > 1) && (offset < 15))
319     {
320       warning_number[offset + 1] = '\0';
321       fprintf(stderr, "libpng warning no. %s: %s",
322          warning_number, warning_message + offset);
323       fprintf(stderr, PNG_STRING_NEWLINE);
324     }
325     else
326     {
327       fprintf(stderr, "libpng warning: %s",
328          warning_message);
329       fprintf(stderr, PNG_STRING_NEWLINE);
330     }
331   }
332   else
333#  endif
334   {
335     fprintf(stderr, "libpng warning: %s", warning_message);
336     fprintf(stderr, PNG_STRING_NEWLINE);
337   }
338#else
339   warning_message = warning_message; /* Make compiler happy */
340#endif
341   png_ptr = png_ptr; /* Make compiler happy */
342}
343#endif /* PNG_WARNINGS_SUPPORTED */
344
345/* This function is called when the application wants to use another method
346 * of handling errors and warnings.  Note that the error function MUST NOT
347 * return to the calling routine or serious problems will occur.  The return
348 * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1)
349 */
350void PNGAPI
351png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
352   png_error_ptr error_fn, png_error_ptr warning_fn)
353{
354   if (png_ptr == NULL)
355      return;
356   png_ptr->error_ptr = error_ptr;
357   png_ptr->error_fn = error_fn;
358   png_ptr->warning_fn = warning_fn;
359}
360
361
362/* This function returns a pointer to the error_ptr associated with the user
363 * functions.  The application should free any memory associated with this
364 * pointer before png_write_destroy and png_read_destroy are called.
365 */
366png_voidp PNGAPI
367png_get_error_ptr(png_structp png_ptr)
368{
369   if (png_ptr == NULL)
370      return NULL;
371   return ((png_voidp)png_ptr->error_ptr);
372}
373
374
375#ifdef PNG_ERROR_NUMBERS_SUPPORTED
376void PNGAPI
377png_set_strip_error_numbers(png_structp png_ptr, png_uint_32 strip_mode)
378{
379   if (png_ptr != NULL)
380   {
381     png_ptr->flags &=
382       ((~(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
383   }
384}
385#endif
386#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
387