2 /* pngerror.c - stub functions for i/o and memory allocation
3 *
4 * libpng 1.0.9 - January 31, 2001
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2001 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 */
16 #define PNG_INTERNAL
17 #include "png.h"
19 static void /* PRIVATE */
20 png_default_error PNGARG((png_structp png_ptr,
21 png_const_charp message));
22 static void /* PRIVATE */
23 png_default_warning PNGARG((png_structp png_ptr,
24 png_const_charp message));
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 */
31 void PNGAPI
32 png_error(png_structp png_ptr, png_const_charp message)
33 {
34 if (png_ptr->error_fn != NULL)
35 (*(png_ptr->error_fn))(png_ptr, message);
37 /* if the following returns or doesn't exist, use the default function,
38 which will not return */
39 png_default_error(png_ptr, message);
40 }
42 /* This function is called whenever there is a non-fatal error. This function
43 * should not be changed. If there is a need to handle warnings differently,
44 * you should supply a replacement warning function and use
45 * png_set_error_fn() to replace the warning function at run-time.
46 */
47 void PNGAPI
48 png_warning(png_structp png_ptr, png_const_charp message)
49 {
50 if (png_ptr->warning_fn != NULL)
51 (*(png_ptr->warning_fn))(png_ptr, message);
52 else
53 png_default_warning(png_ptr, message);
54 }
56 /* These utilities are used internally to build an error message that relates
57 * to the current chunk. The chunk name comes from png_ptr->chunk_name,
58 * this is used to prefix the message. The message is limited in length
59 * to 63 bytes, the name characters are output as hex digits wrapped in []
60 * if the character is invalid.
61 */
62 #define isnonalpha(c) ((c) < 41 || (c) > 122 || ((c) > 90 && (c) < 97))
63 static PNG_CONST char png_digit[16] = {
64 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
65 };
67 static void /* PRIVATE */
68 png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp message)
69 {
70 int iout = 0, iin = 0;
72 while (iin < 4)
73 {
74 int c = png_ptr->chunk_name[iin++];
75 if (isnonalpha(c))
76 {
77 buffer[iout++] = '[';
78 buffer[iout++] = png_digit[(c & 0xf0) >> 4];
79 buffer[iout++] = png_digit[c & 0x0f];
80 buffer[iout++] = ']';
81 }
82 else
83 {
84 buffer[iout++] = (png_byte)c;
85 }
86 }
88 if (message == NULL)
89 buffer[iout] = 0;
90 else
91 {
92 buffer[iout++] = ':';
93 buffer[iout++] = ' ';
94 png_memcpy(buffer+iout, message, 64);
95 buffer[iout+63] = 0;
96 }
97 }
99 void PNGAPI
100 png_chunk_error(png_structp png_ptr, png_const_charp message)
101 {
102 char msg[18+64];
103 png_format_buffer(png_ptr, msg, message);
104 png_error(png_ptr, msg);
105 }
107 void PNGAPI
108 png_chunk_warning(png_structp png_ptr, png_const_charp message)
109 {
110 char msg[16+64];
111 png_format_buffer(png_ptr, msg, message);
112 png_warning(png_ptr, msg);
113 }
115 /* This is the default error handling function. Note that replacements for
116 * this function MUST NOT RETURN, or the program will likely crash. This
117 * function is used by default, or if the program supplies NULL for the
118 * error function pointer in png_set_error_fn().
119 */
120 static void /* PRIVATE */
121 png_default_error(png_structp png_ptr, png_const_charp message)
122 {
123 #ifndef PNG_NO_CONSOLE_IO
124 fprintf(stderr, "libpng error: %s\n", message);
125 #else
126 if (message)
127 /* make compiler happy */ ;
128 #endif
130 #ifdef PNG_SETJMP_SUPPORTED
131 # ifdef USE_FAR_KEYWORD
132 {
133 jmp_buf jmpbuf;
134 png_memcpy(jmpbuf,png_ptr->jmpbuf,sizeof(jmp_buf));
135 longjmp(jmpbuf, 1);
136 }
137 # else
138 longjmp(png_ptr->jmpbuf, 1);
139 # endif
140 #else
141 if (png_ptr)
142 /* make compiler happy */ ;
143 PNG_ABORT();
144 #endif
145 }
147 /* This function is called when there is a warning, but the library thinks
148 * it can continue anyway. Replacement functions don't have to do anything
149 * here if you don't want them to. In the default configuration, png_ptr is
150 * not used, but it is passed in case it may be useful.
151 */
152 static void /* PRIVATE */
153 png_default_warning(png_structp png_ptr, png_const_charp message)
154 {
155 #ifndef PNG_NO_CONSOLE_IO
156 fprintf(stderr, "libpng warning: %s\n", message);
157 #else
158 if (message)
159 /* appease compiler */ ;
160 #endif
161 if (png_ptr)
162 return;
163 }
165 /* This function is called when the application wants to use another method
166 * of handling errors and warnings. Note that the error function MUST NOT
167 * return to the calling routine or serious problems will occur. The return
168 * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1)
169 */
170 void PNGAPI
171 png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
172 png_error_ptr error_fn, png_error_ptr warning_fn)
173 {
174 png_ptr->error_ptr = error_ptr;
175 png_ptr->error_fn = error_fn;
176 png_ptr->warning_fn = warning_fn;
177 }
180 /* This function returns a pointer to the error_ptr associated with the user
181 * functions. The application should free any memory associated with this
182 * pointer before png_write_destroy and png_read_destroy are called.
183 */
184 png_voidp PNGAPI
185 png_get_error_ptr(png_structp png_ptr)
186 {
187 return ((png_voidp)png_ptr->error_ptr);
188 }