1
2/* pngerror.c - stub functions for i/o and memory allocation
3 *
4 * Last changed in libpng 1.2.19 August 18, 2007
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2007 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
19#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
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 */
34void PNGAPI
35png_error(png_structp png_ptr, png_const_charp error_message)
36{
37#ifdef PNG_ERROR_NUMBERS_SUPPORTED
38   char msg[16];
39   if (png_ptr != NULL)
40   {
41     if (png_ptr->flags&
42       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
43     {
44       if (*error_message == '#')
45       {
46           int offset;
47           for (offset=1; offset<15; offset++)
48              if (*(error_message+offset) == ' ')
49                  break;
50           if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
51           {
52              int i;
53              for (i=0; i<offset-1; i++)
54                 msg[i]=error_message[i+1];
55              msg[i]='\0';
56              error_message=msg;
57           }
58           else
59              error_message+=offset;
60       }
61       else
62       {
63           if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
64           {
65              msg[0]='0';
66              msg[1]='\0';
67              error_message=msg;
68           }
69       }
70     }
71   }
72#endif
73   if (png_ptr != NULL && png_ptr->error_fn != NULL)
74      (*(png_ptr->error_fn))(png_ptr, error_message);
75
76   /* If the custom handler doesn't exist, or if it returns,
77      use the default handler, which will not return. */
78   png_default_error(png_ptr, error_message);
79}
80
81#ifndef PNG_NO_WARNINGS
82/* This function is called whenever there is a non-fatal error.  This function
83 * should not be changed.  If there is a need to handle warnings differently,
84 * you should supply a replacement warning function and use
85 * png_set_error_fn() to replace the warning function at run-time.
86 */
87void PNGAPI
88png_warning(png_structp png_ptr, png_const_charp warning_message)
89{
90   int offset = 0;
91   if (png_ptr != NULL)
92   {
93#ifdef PNG_ERROR_NUMBERS_SUPPORTED
94   if (png_ptr->flags&
95     (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
96#endif
97     {
98       if (*warning_message == '#')
99       {
100           for (offset=1; offset<15; offset++)
101              if (*(warning_message+offset) == ' ')
102                  break;
103       }
104     }
105     if (png_ptr != NULL && png_ptr->warning_fn != NULL)
106        (*(png_ptr->warning_fn))(png_ptr, warning_message+offset);
107   }
108   else
109      png_default_warning(png_ptr, warning_message+offset);
110}
111#endif /* PNG_NO_WARNINGS */
112
113
114/* These utilities are used internally to build an error message that relates
115 * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
116 * this is used to prefix the message.  The message is limited in length
117 * to 63 bytes, the name characters are output as hex digits wrapped in []
118 * if the character is invalid.
119 */
120#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
121static PNG_CONST char png_digit[16] = {
122   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
123   'A', 'B', 'C', 'D', 'E', 'F'
124};
125
126static void /* PRIVATE */
127png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp
128   error_message)
129{
130   int iout = 0, iin = 0;
131
132   while (iin < 4)
133   {
134      int c = png_ptr->chunk_name[iin++];
135      if (isnonalpha(c))
136      {
137         buffer[iout++] = '[';
138         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
139         buffer[iout++] = png_digit[c & 0x0f];
140         buffer[iout++] = ']';
141      }
142      else
143      {
144         buffer[iout++] = (png_byte)c;
145      }
146   }
147
148   if (error_message == NULL)
149      buffer[iout] = 0;
150   else
151   {
152      buffer[iout++] = ':';
153      buffer[iout++] = ' ';
154      png_strncpy(buffer+iout, error_message, 63);
155      buffer[iout+63] = 0;
156   }
157}
158
159#ifdef PNG_READ_SUPPORTED
160void PNGAPI
161png_chunk_error(png_structp png_ptr, png_const_charp error_message)
162{
163   char msg[18+64];
164   if (png_ptr == NULL)
165     png_error(png_ptr, error_message);
166   else
167   {
168     png_format_buffer(png_ptr, msg, error_message);
169     png_error(png_ptr, msg);
170   }
171}
172
173#ifndef PNG_NO_WARNINGS
174void PNGAPI
175png_chunk_warning(png_structp png_ptr, png_const_charp warning_message)
176{
177   char msg[18+64];
178   if (png_ptr == NULL)
179     png_warning(png_ptr, warning_message);
180   else
181   {
182     png_format_buffer(png_ptr, msg, warning_message);
183     png_warning(png_ptr, msg);
184   }
185}
186#endif /* PNG_NO_WARNINGS */
187
188#endif /* PNG_READ_SUPPORTED */
189
190/* This is the default error handling function.  Note that replacements for
191 * this function MUST NOT RETURN, or the program will likely crash.  This
192 * function is used by default, or if the program supplies NULL for the
193 * error function pointer in png_set_error_fn().
194 */
195static void /* PRIVATE */
196png_default_error(png_structp png_ptr, png_const_charp error_message)
197{
198#ifndef PNG_NO_CONSOLE_IO
199#ifdef PNG_ERROR_NUMBERS_SUPPORTED
200   if (*error_message == '#')
201   {
202     int offset;
203     char error_number[16];
204     for (offset=0; offset<15; offset++)
205     {
206         error_number[offset] = *(error_message+offset+1);
207         if (*(error_message+offset) == ' ')
208             break;
209     }
210     if((offset > 1) && (offset < 15))
211     {
212       error_number[offset-1]='\0';
213       fprintf(stderr, "libpng error no. %s: %s\n", error_number,
214          error_message+offset);
215     }
216     else
217       fprintf(stderr, "libpng error: %s, offset=%d\n", error_message,offset);
218   }
219   else
220#endif
221   fprintf(stderr, "libpng error: %s\n", error_message);
222#endif
223
224#ifdef PNG_SETJMP_SUPPORTED
225   if (png_ptr)
226   {
227#  ifdef USE_FAR_KEYWORD
228   {
229      jmp_buf jmpbuf;
230      png_memcpy(jmpbuf, png_ptr->jmpbuf, png_sizeof(jmp_buf));
231      longjmp(jmpbuf, 1);
232   }
233#  else
234   longjmp(png_ptr->jmpbuf, 1);
235#  endif
236   }
237#else
238   PNG_ABORT();
239#endif
240#ifdef PNG_NO_CONSOLE_IO
241   error_message = error_message; /* make compiler happy */
242#endif
243}
244
245#ifndef PNG_NO_WARNINGS
246/* This function is called when there is a warning, but the library thinks
247 * it can continue anyway.  Replacement functions don't have to do anything
248 * here if you don't want them to.  In the default configuration, png_ptr is
249 * not used, but it is passed in case it may be useful.
250 */
251static void /* PRIVATE */
252png_default_warning(png_structp png_ptr, png_const_charp warning_message)
253{
254#ifndef PNG_NO_CONSOLE_IO
255#  ifdef PNG_ERROR_NUMBERS_SUPPORTED
256   if (*warning_message == '#')
257   {
258     int offset;
259     char warning_number[16];
260     for (offset=0; offset<15; offset++)
261     {
262        warning_number[offset]=*(warning_message+offset+1);
263        if (*(warning_message+offset) == ' ')
264            break;
265     }
266     if((offset > 1) && (offset < 15))
267     {
268       warning_number[offset-1]='\0';
269       fprintf(stderr, "libpng warning no. %s: %s\n", warning_number,
270          warning_message+offset);
271     }
272     else
273       fprintf(stderr, "libpng warning: %s\n", warning_message);
274   }
275   else
276#  endif
277     fprintf(stderr, "libpng warning: %s\n", warning_message);
278#else
279   warning_message = warning_message; /* make compiler happy */
280#endif
281   png_ptr = png_ptr; /* make compiler happy */
282}
283#endif /* PNG_NO_WARNINGS */
284
285/* This function is called when the application wants to use another method
286 * of handling errors and warnings.  Note that the error function MUST NOT
287 * return to the calling routine or serious problems will occur.  The return
288 * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1)
289 */
290void PNGAPI
291png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
292   png_error_ptr error_fn, png_error_ptr warning_fn)
293{
294   if (png_ptr == NULL)
295      return;
296   png_ptr->error_ptr = error_ptr;
297   png_ptr->error_fn = error_fn;
298   png_ptr->warning_fn = warning_fn;
299}
300
301
302/* This function returns a pointer to the error_ptr associated with the user
303 * functions.  The application should free any memory associated with this
304 * pointer before png_write_destroy and png_read_destroy are called.
305 */
306png_voidp PNGAPI
307png_get_error_ptr(png_structp png_ptr)
308{
309   if (png_ptr == NULL)
310      return NULL;
311   return ((png_voidp)png_ptr->error_ptr);
312}
313
314
315#ifdef PNG_ERROR_NUMBERS_SUPPORTED
316void PNGAPI
317png_set_strip_error_numbers(png_structp png_ptr, png_uint_32 strip_mode)
318{
319   if(png_ptr != NULL)
320   {
321     png_ptr->flags &=
322       ((~(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
323   }
324}
325#endif
326#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
327