www.pudn.com > Image_png.rar > pngerror.c

 
/* pngerror.c - stub functions for i/o and memory allocation 
 * 
 * libpng 1.0.1 
 * For conditions of distribution and use, see copyright notice in png.h 
 * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc. 
 * Copyright (c) 1996, 1997 Andreas Dilger 
 * Copyright (c) 1998, Glenn Randers-Pehrson 
 * March 15, 1998 
 * 
 * This file provides a location for all error handling.  Users which 
 * need special error handling are expected to write replacement functions 
 * and use png_set_error_fn() to use those functions.  See the instructions 
 * at each function. 
 */ 
 
#define PNG_INTERNAL 
#include "png.h" 
 
static void png_default_error PNGARG((png_structp png_ptr, 
                                      png_const_charp message)); 
static void png_default_warning PNGARG((png_structp png_ptr, 
                                        png_const_charp message)); 
 
/* This function is called whenever there is a fatal error.  This function 
 * should not be changed.  If there is a need to handle errors differently, 
 * you should supply a replacement error function and use png_set_error_fn() 
 * to replace the error function at run-time. 
 */ 
void 
png_error(png_structp png_ptr, png_const_charp message) 
{ 
   if (png_ptr->error_fn != NULL) 
      (*(png_ptr->error_fn))(png_ptr, message); 
 
   /* if the following returns or doesn't exist, use the default function, 
      which will not return */ 
   png_default_error(png_ptr, message); 
} 
 
/* This function is called whenever there is a non-fatal error.  This function 
 * should not be changed.  If there is a need to handle warnings differently, 
 * you should supply a replacement warning function and use 
 * png_set_error_fn() to replace the warning function at run-time. 
 */ 
void 
png_warning(png_structp png_ptr, png_const_charp message) 
{ 
   if (png_ptr->warning_fn != NULL) 
      (*(png_ptr->warning_fn))(png_ptr, message); 
   else 
      png_default_warning(png_ptr, message); 
} 
 
/* These utilities are used internally to build an error message which relates 
 * to the current chunk.  The chunk name comes from png_ptr->chunk_name, 
 * this is used to prefix the message.  The message is limited in length 
 * to 63 bytes, the name characters are output as hex digits wrapped in [] 
 * if the character is invalid. 
 */ 
#define isnonalpha(c) ((c) < 41 || (c) > 122 || ((c) > 90 && (c) < 97)) 
static PNG_CONST char png_digit[16] = { 
   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' 
}; 
 
static void 
png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp message) 
{ 
   int iout = 0, iin = 0; 
 
   while (iin < 4) { 
      int c = png_ptr->chunk_name[iin++]; 
      if (isnonalpha(c)) { 
         buffer[iout++] = '['; 
         buffer[iout++] = png_digit[(c & 0xf0) >> 4]; 
         buffer[iout++] = png_digit[c & 0xf]; 
         buffer[iout++] = ']'; 
      } else { 
         buffer[iout++] = c; 
      } 
   } 
 
   if (message == NULL) 
      buffer[iout] = 0; 
   else { 
      buffer[iout++] = ':'; 
      buffer[iout++] = ' '; 
      png_memcpy(buffer+iout, message, 64); 
      buffer[iout+63] = 0; 
   } 
} 
 
void 
png_chunk_error(png_structp png_ptr, png_const_charp message) 
{ 
   char msg[16+64]; 
   png_format_buffer(png_ptr, msg, message); 
   png_error(png_ptr, msg); 
} 
 
void 
png_chunk_warning(png_structp png_ptr, png_const_charp message) 
{ 
   char msg[16+64]; 
   png_format_buffer(png_ptr, msg, message); 
   png_warning(png_ptr, msg); 
} 
 
/* This is the default error handling function.  Note that replacements for 
 * this function MUST NOT RETURN, or the program will likely crash.  This 
 * function is used by default, or if the program supplies NULL for the 
 * error function pointer in png_set_error_fn(). 
 */ 
static void 
png_default_error(png_structp png_ptr, png_const_charp message) 
{ 
#ifndef PNG_NO_STDIO 
   fprintf(stderr, "libpng error: %s\n", message); 
#endif 
 
#ifdef USE_FAR_KEYWORD 
   { 
      jmp_buf jmpbuf; 
      png_memcpy(jmpbuf,png_ptr->jmpbuf,sizeof(jmp_buf)); 
      longjmp(jmpbuf, 1); 
   } 
#else 
   longjmp(png_ptr->jmpbuf, 1); 
#endif 
} 
 
/* This function is called when there is a warning, but the library thinks 
 * it can continue anyway.  Replacement functions don't have to do anything 
 * here if you don't want to.  In the default configuration, png_ptr is 
 * not used, but it is passed in case it may be useful. 
 */ 
static void 
png_default_warning(png_structp png_ptr, png_const_charp message) 
{ 
   if (png_ptr == NULL) 
      return; 
 
#ifndef PNG_NO_STDIO 
   fprintf(stderr, "libpng warning: %s\n", message); 
#endif 
} 
 
/* This function is called when the application wants to use another method 
 * of handling errors and warnings.  Note that the error function MUST NOT 
 * return to the calling routine or serious problems will occur.  The return 
 * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1) 
 */ 
void 
png_set_error_fn(png_structp png_ptr, png_voidp error_ptr, 
   png_error_ptr error_fn, png_error_ptr warning_fn) 
{ 
   png_ptr->error_ptr = error_ptr; 
   png_ptr->error_fn = error_fn; 
   png_ptr->warning_fn = warning_fn; 
} 
 
 
/* This function returns a pointer to the error_ptr associated with the user 
 * functions.  The application should free any memory associated with this 
 * pointer before png_write_destroy and png_read_destroy are called. 
 */ 
png_voidp 
png_get_error_ptr(png_structp png_ptr) 
{ 
   return ((png_voidp)png_ptr->error_ptr); 
}