src/png/pngerror.c

   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
  18 #include "png.h"
  19
  20 static void png_default_error PNGARG((png_structp png_ptr,
  21                                       png_const_charp message));
  22 static 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  */
  30 void
  31 png_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  */
  46 void
  47 png_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))
  62 static 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
  66 static void
  67 png_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
  93 void
  94 png_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
 101 void
 102 png_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  */
 114 static void
 115 png_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  */
 137 static void
 138 png_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  */
 153 void
 154 png_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  */
 167 png_voidp
 168 png_get_error_ptr(png_structp png_ptr)
 169 {
 170    return ((png_voidp)png_ptr->error_ptr);
 171 }
 172
 173
 174