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1
2/* pngerror.c - stub functions for i/o and memory allocation
3 *
4 * libpng 1.0.1
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
7 * Copyright (c) 1996, 1997 Andreas Dilger
8 * Copyright (c) 1998, Glenn Randers-Pehrson
9 * March 15, 1998
10 *
11 * This file provides a location for all error handling. Users which
12 * need special error handling are expected to write replacement functions
13 * and use png_set_error_fn() to use those functions. See the instructions
14 * at each function.
15 */
16
17#define PNG_INTERNAL
1f0299c1 18#include "../png/png.h"
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19
20static void png_default_error PNGARG((png_structp png_ptr,
21 png_const_charp message));
22static void png_default_warning PNGARG((png_structp png_ptr,
23 png_const_charp message));
24
25/* This function is called whenever there is a fatal error. This function
26 * should not be changed. If there is a need to handle errors differently,
27 * you should supply a replacement error function and use png_set_error_fn()
28 * to replace the error function at run-time.
29 */
30void
31png_error(png_structp png_ptr, png_const_charp message)
32{
33 if (png_ptr->error_fn != NULL)
34 (*(png_ptr->error_fn))(png_ptr, message);
35
36 /* if the following returns or doesn't exist, use the default function,
37 which will not return */
38 png_default_error(png_ptr, message);
39}
40
41/* This function is called whenever there is a non-fatal error. This function
42 * should not be changed. If there is a need to handle warnings differently,
43 * you should supply a replacement warning function and use
44 * png_set_error_fn() to replace the warning function at run-time.
45 */
46void
47png_warning(png_structp png_ptr, png_const_charp message)
48{
49 if (png_ptr->warning_fn != NULL)
50 (*(png_ptr->warning_fn))(png_ptr, message);
51 else
52 png_default_warning(png_ptr, message);
53}
54
55/* These utilities are used internally to build an error message which relates
56 * to the current chunk. The chunk name comes from png_ptr->chunk_name,
57 * this is used to prefix the message. The message is limited in length
58 * to 63 bytes, the name characters are output as hex digits wrapped in []
59 * if the character is invalid.
60 */
61#define isnonalpha(c) ((c) < 41 || (c) > 122 || ((c) > 90 && (c) < 97))
62static PNG_CONST char png_digit[16] = {
63 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
64};
65
66static void
67png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp message)
68{
69 int iout = 0, iin = 0;
70
71 while (iin < 4) {
72 int c = png_ptr->chunk_name[iin++];
73 if (isnonalpha(c)) {
74 buffer[iout++] = '[';
75 buffer[iout++] = png_digit[(c & 0xf0) >> 4];
76 buffer[iout++] = png_digit[c & 0xf];
77 buffer[iout++] = ']';
78 } else {
79 buffer[iout++] = c;
80 }
81 }
82
83 if (message == NULL)
84 buffer[iout] = 0;
85 else {
86 buffer[iout++] = ':';
87 buffer[iout++] = ' ';
88 png_memcpy(buffer+iout, message, 64);
89 buffer[iout+63] = 0;
90 }
91}
92
93void
94png_chunk_error(png_structp png_ptr, png_const_charp message)
95{
96 char msg[16+64];
97 png_format_buffer(png_ptr, msg, message);
98 png_error(png_ptr, msg);
99}
100
101void
102png_chunk_warning(png_structp png_ptr, png_const_charp message)
103{
104 char msg[16+64];
105 png_format_buffer(png_ptr, msg, message);
106 png_warning(png_ptr, msg);
107}
108
109/* This is the default error handling function. Note that replacements for
110 * this function MUST NOT RETURN, or the program will likely crash. This
111 * function is used by default, or if the program supplies NULL for the
112 * error function pointer in png_set_error_fn().
113 */
114static void
115png_default_error(png_structp png_ptr, png_const_charp message)
116{
117#ifndef PNG_NO_STDIO
118 fprintf(stderr, "libpng error: %s\n", message);
119#endif
120
121#ifdef USE_FAR_KEYWORD
122 {
123 jmp_buf jmpbuf;
124 png_memcpy(jmpbuf,png_ptr->jmpbuf,sizeof(jmp_buf));
125 longjmp(jmpbuf, 1);
126 }
127#else
128 longjmp(png_ptr->jmpbuf, 1);
129#endif
130}
131
132/* This function is called when there is a warning, but the library thinks
133 * it can continue anyway. Replacement functions don't have to do anything
134 * here if you don't want to. In the default configuration, png_ptr is
135 * not used, but it is passed in case it may be useful.
136 */
137static void
138png_default_warning(png_structp png_ptr, png_const_charp message)
139{
140 if (png_ptr == NULL)
141 return;
142
143#ifndef PNG_NO_STDIO
144 fprintf(stderr, "libpng warning: %s\n", message);
145#endif
146}
147
148/* This function is called when the application wants to use another method
149 * of handling errors and warnings. Note that the error function MUST NOT
150 * return to the calling routine or serious problems will occur. The return
151 * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1)
152 */
153void
154png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
155 png_error_ptr error_fn, png_error_ptr warning_fn)
156{
157 png_ptr->error_ptr = error_ptr;
158 png_ptr->error_fn = error_fn;
159 png_ptr->warning_fn = warning_fn;
160}
161
162
163/* This function returns a pointer to the error_ptr associated with the user
164 * functions. The application should free any memory associated with this
165 * pointer before png_write_destroy and png_read_destroy are called.
166 */
167png_voidp
168png_get_error_ptr(png_structp png_ptr)
169{
170 return ((png_voidp)png_ptr->error_ptr);
171}
172
173
174