1
2/* pngerror.c - stub functions for i/o and memory allocation
3 *
4 * libpng version 1.2.7 - September 12, 2004
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2004 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
19static void /* PRIVATE */
20png_default_error PNGARG((png_structp png_ptr,
21  png_const_charp error_message));
22static void /* PRIVATE */
23png_default_warning PNGARG((png_structp png_ptr,
24  png_const_charp warning_message));
25
26/* This function is called whenever there is a fatal error.  This function
27 * should not be changed.  If there is a need to handle errors differently,
28 * you should supply a replacement error function and use png_set_error_fn()
29 * to replace the error function at run-time.
30 */
31void PNGAPI
32png_error(png_structp png_ptr, png_const_charp error_message)
33{
34#ifdef PNG_ERROR_NUMBERS_SUPPORTED
35   char msg[16];
36   if (png_ptr->flags&(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
37   {
38     if (*error_message == '#')
39     {
40         int offset;
41         for (offset=1; offset<15; offset++)
42            if (*(error_message+offset) == ' ')
43                break;
44         if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
45         {
46            int i;
47            for (i=0; i<offset-1; i++)
48               msg[i]=error_message[i+1];
49            msg[i]='\0';
50            error_message=msg;
51         }
52         else
53            error_message+=offset;
54     }
55     else
56     {
57         if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
58         {
59            msg[0]='0';
60            msg[1]='\0';
61            error_message=msg;
62         }
63     }
64   }
65#endif
66   if (png_ptr != NULL && png_ptr->error_fn != NULL)
67      (*(png_ptr->error_fn))(png_ptr, error_message);
68
69   /* If the custom handler doesn't exist, or if it returns,
70      use the default handler, which will not return. */
71   png_default_error(png_ptr, error_message);
72}
73
74/* This function is called whenever there is a non-fatal error.  This function
75 * should not be changed.  If there is a need to handle warnings differently,
76 * you should supply a replacement warning function and use
77 * png_set_error_fn() to replace the warning function at run-time.
78 */
79void PNGAPI
80png_warning(png_structp png_ptr, png_const_charp warning_message)
81{
82   int offset = 0;
83#ifdef PNG_ERROR_NUMBERS_SUPPORTED
84   if (png_ptr->flags&(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
85#endif
86   {
87     if (*warning_message == '#')
88     {
89         for (offset=1; offset<15; offset++)
90            if (*(warning_message+offset) == ' ')
91                break;
92     }
93   }
94   if (png_ptr != NULL && png_ptr->warning_fn != NULL)
95      (*(png_ptr->warning_fn))(png_ptr, warning_message+offset);
96   else
97      png_default_warning(png_ptr, warning_message+offset);
98}
99
100/* These utilities are used internally to build an error message that relates
101 * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
102 * this is used to prefix the message.  The message is limited in length
103 * to 63 bytes, the name characters are output as hex digits wrapped in []
104 * if the character is invalid.
105 */
106#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
107static PNG_CONST char png_digit[16] = {
108   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
109   'A', 'B', 'C', 'D', 'E', 'F'
110};
111
112static void /* PRIVATE */
113png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp
114   error_message)
115{
116   int iout = 0, iin = 0;
117
118   while (iin < 4)
119   {
120      int c = png_ptr->chunk_name[iin++];
121      if (isnonalpha(c))
122      {
123         buffer[iout++] = '[';
124         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
125         buffer[iout++] = png_digit[c & 0x0f];
126         buffer[iout++] = ']';
127      }
128      else
129      {
130         buffer[iout++] = (png_byte)c;
131      }
132   }
133
134   if (error_message == NULL)
135      buffer[iout] = 0;
136   else
137   {
138      buffer[iout++] = ':';
139      buffer[iout++] = ' ';
140      png_strncpy(buffer+iout, error_message, 63);
141      buffer[iout+63] = 0;
142   }
143}
144
145void PNGAPI
146png_chunk_error(png_structp png_ptr, png_const_charp error_message)
147{
148   char msg[18+64];
149   png_format_buffer(png_ptr, msg, error_message);
150   png_error(png_ptr, msg);
151}
152
153void PNGAPI
154png_chunk_warning(png_structp png_ptr, png_const_charp warning_message)
155{
156   char msg[18+64];
157   png_format_buffer(png_ptr, msg, warning_message);
158   png_warning(png_ptr, msg);
159}
160
161/* This is the default error handling function.  Note that replacements for
162 * this function MUST NOT RETURN, or the program will likely crash.  This
163 * function is used by default, or if the program supplies NULL for the
164 * error function pointer in png_set_error_fn().
165 */
166static void /* PRIVATE */
167png_default_error(png_structp png_ptr, png_const_charp error_message)
168{
169#ifndef PNG_NO_CONSOLE_IO
170#ifdef PNG_ERROR_NUMBERS_SUPPORTED
171   if (*error_message == '#')
172   {
173     int offset;
174     char error_number[16];
175     for (offset=0; offset<15; offset++)
176     {
177         error_number[offset] = *(error_message+offset+1);
178         if (*(error_message+offset) == ' ')
179             break;
180     }
181     if((offset > 1) && (offset < 15))
182     {
183       error_number[offset-1]='\0';
184       fprintf(stderr, "libpng error no. %s: %s\n", error_number,
185          error_message+offset);
186     }
187     else
188       fprintf(stderr, "libpng error: %s, offset=%d\n", error_message,offset);
189   }
190   else
191#endif
192   fprintf(stderr, "libpng error: %s\n", error_message);
193#endif
194
195#ifdef PNG_SETJMP_SUPPORTED
196#  ifdef USE_FAR_KEYWORD
197   {
198      jmp_buf jmpbuf;
199      png_memcpy(jmpbuf,png_ptr->jmpbuf,png_sizeof(jmp_buf));
200      longjmp(jmpbuf, 1);
201   }
202#  else
203   longjmp(png_ptr->jmpbuf, 1);
204# endif
205#else
206   /* make compiler happy */ ;
207   if (png_ptr)
208   PNG_ABORT();
209#endif
210#ifdef PNG_NO_CONSOLE_IO
211   /* make compiler happy */ ;
212   if (&error_message != NULL)
213      return;
214#endif
215}
216
217/* This function is called when there is a warning, but the library thinks
218 * it can continue anyway.  Replacement functions don't have to do anything
219 * here if you don't want them to.  In the default configuration, png_ptr is
220 * not used, but it is passed in case it may be useful.
221 */
222static void /* PRIVATE */
223png_default_warning(png_structp png_ptr, png_const_charp warning_message)
224{
225#ifndef PNG_NO_CONSOLE_IO
226#  ifdef PNG_ERROR_NUMBERS_SUPPORTED
227   if (*warning_message == '#')
228   {
229     int offset;
230     char warning_number[16];
231     for (offset=0; offset<15; offset++)
232     {
233        warning_number[offset]=*(warning_message+offset+1);
234        if (*(warning_message+offset) == ' ')
235            break;
236     }
237     if((offset > 1) && (offset < 15))
238     {
239       warning_number[offset-1]='\0';
240       fprintf(stderr, "libpng warning no. %s: %s\n", warning_number,
241          warning_message+offset);
242     }
243     else
244       fprintf(stderr, "libpng warning: %s\n", warning_message);
245   }
246   else
247#  endif
248     fprintf(stderr, "libpng warning: %s\n", warning_message);
249#else
250   /* make compiler happy */ ;
251   if (warning_message)
252     return;
253#endif
254   /* make compiler happy */ ;
255   if (png_ptr)
256      return;
257}
258
259/* This function is called when the application wants to use another method
260 * of handling errors and warnings.  Note that the error function MUST NOT
261 * return to the calling routine or serious problems will occur.  The return
262 * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1)
263 */
264void PNGAPI
265png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
266   png_error_ptr error_fn, png_error_ptr warning_fn)
267{
268   png_ptr->error_ptr = error_ptr;
269   png_ptr->error_fn = error_fn;
270   png_ptr->warning_fn = warning_fn;
271}
272
273
274/* This function returns a pointer to the error_ptr associated with the user
275 * functions.  The application should free any memory associated with this
276 * pointer before png_write_destroy and png_read_destroy are called.
277 */
278png_voidp PNGAPI
279png_get_error_ptr(png_structp png_ptr)
280{
281   return ((png_voidp)png_ptr->error_ptr);
282}
283
284
285#ifdef PNG_ERROR_NUMBERS_SUPPORTED
286void PNGAPI
287png_set_strip_error_numbers(png_structp png_ptr, png_uint_32 strip_mode)
288{
289   if(png_ptr != NULL)
290   {
291     png_ptr->flags &=
292       ((~(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
293   }
294}
295#endif
296