pngerror.c revision 4215dd1533c56e1a89ae6f1d6ea68677fac27fda 
1
2/* pngerror.c - stub functions for i/o and memory allocation
3 *
4 * Last changed in libpng 1.2.34 [December 18, 2008]
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2008 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 * This file provides a location for all error handling.  Users who
11 * need special error handling are expected to write replacement functions
12 * and use png_set_error_fn() to use those functions.  See the instructions
13 * at each function.
14 */
15
16#define PNG_INTERNAL
17#include "png.h"
18#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
19
20static void /* PRIVATE */
21png_default_error PNGARG((png_structp png_ptr,
22  png_const_charp error_message));
23#ifndef PNG_NO_WARNINGS
24static void /* PRIVATE */
25png_default_warning PNGARG((png_structp png_ptr,
26  png_const_charp warning_message));
27#endif /* PNG_NO_WARNINGS */
28
29/* This function is called whenever there is a fatal error.  This function
30 * should not be changed.  If there is a need to handle errors differently,
31 * you should supply a replacement error function and use png_set_error_fn()
32 * to replace the error function at run-time.
33 */
34#ifndef PNG_NO_ERROR_TEXT
35void PNGAPI
36png_error(png_structp png_ptr, png_const_charp error_message)
37{
38#ifdef PNG_ERROR_NUMBERS_SUPPORTED
39   char msg[16];
40   if (png_ptr != NULL)
41   {
42     if (png_ptr->flags&
43       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
44     {
45       if (*error_message == '#')
46       {
47         /* Strip "#nnnn " from beginning of error message. */
48           int offset;
49           for (offset = 1; offset<15; offset++)
50              if (error_message[offset] == ' ')
51                  break;
52           if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
53           {
54              int i;
55              for (i = 0; i < offset - 1; i++)
56                 msg[i] = error_message[i + 1];
57              msg[i - 1] = '\0';
58              error_message = msg;
59           }
60           else
61              error_message += offset;
62       }
63       else
64       {
65           if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
66           {
67              msg[0] = '0';
68              msg[1] = '\0';
69              error_message = msg;
70           }
71       }
72     }
73   }
74#endif
75   if (png_ptr != NULL && png_ptr->error_fn != NULL)
76      (*(png_ptr->error_fn))(png_ptr, error_message);
77
78   /* If the custom handler doesn't exist, or if it returns,
79      use the default handler, which will not return. */
80   png_default_error(png_ptr, error_message);
81}
82#else
83void PNGAPI
84png_err(png_structp png_ptr)
85{
86   if (png_ptr != NULL && png_ptr->error_fn != NULL)
87      (*(png_ptr->error_fn))(png_ptr, '\0');
88
89   /* If the custom handler doesn't exist, or if it returns,
90      use the default handler, which will not return. */
91   png_default_error(png_ptr, '\0');
92}
93#endif /* PNG_NO_ERROR_TEXT */
94
95#ifndef PNG_NO_WARNINGS
96/* This function is called whenever there is a non-fatal error.  This function
97 * should not be changed.  If there is a need to handle warnings differently,
98 * you should supply a replacement warning function and use
99 * png_set_error_fn() to replace the warning function at run-time.
100 */
101void PNGAPI
102png_warning(png_structp png_ptr, png_const_charp warning_message)
103{
104   int offset = 0;
105   if (png_ptr != NULL)
106   {
107#ifdef PNG_ERROR_NUMBERS_SUPPORTED
108   if (png_ptr->flags&
109     (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
110#endif
111     {
112       if (*warning_message == '#')
113       {
114           for (offset = 1; offset < 15; offset++)
115              if (warning_message[offset] == ' ')
116                  break;
117       }
118     }
119   }
120   if (png_ptr != NULL && png_ptr->warning_fn != NULL)
121      (*(png_ptr->warning_fn))(png_ptr, warning_message + offset);
122   else
123      png_default_warning(png_ptr, warning_message + offset);
124}
125#endif /* PNG_NO_WARNINGS */
126
127
128/* These utilities are used internally to build an error message that relates
129 * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
130 * this is used to prefix the message.  The message is limited in length
131 * to 63 bytes, the name characters are output as hex digits wrapped in []
132 * if the character is invalid.
133 */
134#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
135static PNG_CONST char png_digit[16] = {
136   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
137   'A', 'B', 'C', 'D', 'E', 'F'
138};
139
140#define PNG_MAX_ERROR_TEXT 64
141
142#if !defined(PNG_NO_WARNINGS) || !defined(PNG_NO_ERROR_TEXT)
143static void /* PRIVATE */
144png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp
145   error_message)
146{
147   int iout = 0, iin = 0;
148
149   while (iin < 4)
150   {
151      int c = png_ptr->chunk_name[iin++];
152      if (isnonalpha(c))
153      {
154         buffer[iout++] = '[';
155         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
156         buffer[iout++] = png_digit[c & 0x0f];
157         buffer[iout++] = ']';
158      }
159      else
160      {
161         buffer[iout++] = (png_byte)c;
162      }
163   }
164
165   if (error_message == NULL)
166      buffer[iout] = '\0';
167   else
168   {
169      buffer[iout++] = ':';
170      buffer[iout++] = ' ';
171      png_memcpy(buffer + iout, error_message, PNG_MAX_ERROR_TEXT);
172      buffer[iout + PNG_MAX_ERROR_TEXT - 1] = '\0';
173   }
174}
175
176#ifdef PNG_READ_SUPPORTED
177void PNGAPI
178png_chunk_error(png_structp png_ptr, png_const_charp error_message)
179{
180   char msg[18+PNG_MAX_ERROR_TEXT];
181   if (png_ptr == NULL)
182     png_error(png_ptr, error_message);
183   else
184   {
185     png_format_buffer(png_ptr, msg, error_message);
186     png_error(png_ptr, msg);
187   }
188}
189#endif /* PNG_READ_SUPPORTED */
190#endif /* !defined(PNG_NO_WARNINGS) || !defined(PNG_NO_ERROR_TEXT) */
191
192#ifndef PNG_NO_WARNINGS
193void PNGAPI
194png_chunk_warning(png_structp png_ptr, png_const_charp warning_message)
195{
196   char msg[18+PNG_MAX_ERROR_TEXT];
197   if (png_ptr == NULL)
198     png_warning(png_ptr, warning_message);
199   else
200   {
201     png_format_buffer(png_ptr, msg, warning_message);
202     png_warning(png_ptr, msg);
203   }
204}
205#endif /* PNG_NO_WARNINGS */
206
207
208/* This is the default error handling function.  Note that replacements for
209 * this function MUST NOT RETURN, or the program will likely crash.  This
210 * function is used by default, or if the program supplies NULL for the
211 * error function pointer in png_set_error_fn().
212 */
213static void /* PRIVATE */
214png_default_error(png_structp png_ptr, png_const_charp error_message)
215{
216#ifndef PNG_NO_CONSOLE_IO
217#ifdef PNG_ERROR_NUMBERS_SUPPORTED
218   if (*error_message == '#')
219   {
220     /* Strip "#nnnn " from beginning of warning message. */
221     int offset;
222     char error_number[16];
223     for (offset = 0; offset<15; offset++)
224     {
225         error_number[offset] = error_message[offset + 1];
226         if (error_message[offset] == ' ')
227             break;
228     }
229     if ((offset > 1) && (offset < 15))
230     {
231       error_number[offset - 1] = '\0';
232       fprintf(stderr, "libpng error no. %s: %s\n", error_number,
233          error_message + offset + 1);
234     }
235     else
236       fprintf(stderr, "libpng error: %s, offset=%d\n", error_message, offset);
237   }
238   else
239#endif
240   fprintf(stderr, "libpng error: %s\n", error_message);
241#endif
242
243#ifdef PNG_SETJMP_SUPPORTED
244   if (png_ptr)
245   {
246#  ifdef USE_FAR_KEYWORD
247   {
248      jmp_buf jmpbuf;
249      png_memcpy(jmpbuf, png_ptr->jmpbuf, png_sizeof(jmp_buf));
250      longjmp(jmpbuf, 1);
251   }
252#  else
253   longjmp(png_ptr->jmpbuf, 1);
254#  endif
255   }
256#else
257   PNG_ABORT();
258#endif
259#ifdef PNG_NO_CONSOLE_IO
260   error_message = error_message; /* make compiler happy */
261#endif
262}
263
264#ifndef PNG_NO_WARNINGS
265/* This function is called when there is a warning, but the library thinks
266 * it can continue anyway.  Replacement functions don't have to do anything
267 * here if you don't want them to.  In the default configuration, png_ptr is
268 * not used, but it is passed in case it may be useful.
269 */
270static void /* PRIVATE */
271png_default_warning(png_structp png_ptr, png_const_charp warning_message)
272{
273#ifndef PNG_NO_CONSOLE_IO
274#  ifdef PNG_ERROR_NUMBERS_SUPPORTED
275   if (*warning_message == '#')
276   {
277     int offset;
278     char warning_number[16];
279     for (offset = 0; offset < 15; offset++)
280     {
281        warning_number[offset] = warning_message[offset + 1];
282        if (warning_message[offset] == ' ')
283            break;
284     }
285     if ((offset > 1) && (offset < 15))
286     {
287       warning_number[offset + 1] = '\0';
288       fprintf(stderr, "libpng warning no. %s: %s\n", warning_number,
289          warning_message + offset);
290     }
291     else
292       fprintf(stderr, "libpng warning: %s\n", warning_message);
293   }
294   else
295#  endif
296     fprintf(stderr, "libpng warning: %s\n", warning_message);
297#else
298   warning_message = warning_message; /* make compiler happy */
299#endif
300   png_ptr = png_ptr; /* make compiler happy */
301}
302#endif /* PNG_NO_WARNINGS */
303
304/* This function is called when the application wants to use another method
305 * of handling errors and warnings.  Note that the error function MUST NOT
306 * return to the calling routine or serious problems will occur.  The return
307 * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1)
308 */
309void PNGAPI
310png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
311   png_error_ptr error_fn, png_error_ptr warning_fn)
312{
313   if (png_ptr == NULL)
314      return;
315   png_ptr->error_ptr = error_ptr;
316   png_ptr->error_fn = error_fn;
317   png_ptr->warning_fn = warning_fn;
318}
319
320
321/* This function returns a pointer to the error_ptr associated with the user
322 * functions.  The application should free any memory associated with this
323 * pointer before png_write_destroy and png_read_destroy are called.
324 */
325png_voidp PNGAPI
326png_get_error_ptr(png_structp png_ptr)
327{
328   if (png_ptr == NULL)
329      return NULL;
330   return ((png_voidp)png_ptr->error_ptr);
331}
332
333
334#ifdef PNG_ERROR_NUMBERS_SUPPORTED
335void PNGAPI
336png_set_strip_error_numbers(png_structp png_ptr, png_uint_32 strip_mode)
337{
338   if (png_ptr != NULL)
339   {
340     png_ptr->flags &=
341       ((~(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
342   }
343}
344#endif
345#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
346