/* pngerror.c - stub functions for i/o and memory allocation * * libpng 1.0.9 - January 31, 2001 * For conditions of distribution and use, see copyright notice in png.h * Copyright (c) 1998-2001 Glenn Randers-Pehrson * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * * This file provides a location for all error handling.  Users who * 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 /* PRIVATE */png_default_error PNGARG((png_structp png_ptr,                                      png_const_charp message));static void /* PRIVATE */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 PNGAPIpng_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 PNGAPIpng_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 that 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 /* PRIVATE */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 & 0x0f];         buffer[iout++] = ']';      }      else      {         buffer[iout++] = (png_byte)c;      }   }   if (message == NULL)      buffer[iout] = 0;   else   {      buffer[iout++] = ':';      buffer[iout++] = ' ';      png_memcpy(buffer+iout, message, 64);      buffer[iout+63] = 0;   }}void PNGAPIpng_chunk_error(png_structp png_ptr, png_const_charp message){   char msg[18+64];   png_format_buffer(png_ptr, msg, message);   png_error(png_ptr, msg);}void PNGAPIpng_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 /* PRIVATE */png_default_error(png_structp png_ptr, png_const_charp message){#ifndef PNG_NO_CONSOLE_IO   fprintf(stderr, "libpng error: %s\n", message);#else   if (message)     /* make compiler happy */ ;#endif#ifdef PNG_SETJMP_SUPPORTED#  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#else   if (png_ptr)     /* make compiler happy */ ;   PNG_ABORT();#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 them to.  In the default configuration, png_ptr is * not used, but it is passed in case it may be useful. */static void /* PRIVATE */png_default_warning(png_structp png_ptr, png_const_charp message){#ifndef PNG_NO_CONSOLE_IO   fprintf(stderr, "libpng warning: %s\n", message);#else   if (message)     /* appease compiler */ ;#endif   if (png_ptr)      return;}/* 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 PNGAPIpng_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 PNGAPIpng_get_error_ptr(png_structp png_ptr){   return ((png_voidp)png_ptr->error_ptr);}