www.pudn.com > imgport.rar > jerror.c, change:2008-11-05,size:8053b


/* 
 * jerror.c 
 * 
 * Copyright (C) 1991-1998, Thomas G. Lane. 
 * This file is part of the Independent JPEG Group's software. 
 * For conditions of distribution and use, see the accompanying README file. 
 * 
 * This file contains simple error-reporting and trace-message routines. 
 * These are suitable for Unix-like systems and others where writing to 
 * stderr is the right thing to do.  Many applications will want to replace 
 * some or all of these routines. 
 * 
 * If you define USE_WINDOWS_MESSAGEBOX in jconfig.h or in the makefile, 
 * you get a Windows-specific hack to display error messages in a dialog box. 
 * It ain't much, but it beats dropping error messages into the bit bucket, 
 * which is what happens to output to stderr under most Windows C compilers. 
 * 
 * These routines are used by both the compression and decompression code. 
 */ 
 
/* this is not a core library module, so it doesn't define JPEG_INTERNALS */ 
#include "jinclude.h" 
#include "jpeglib.h" 
#include "jversion.h" 
#include "jerror.h" 
 
#ifdef USE_WINDOWS_MESSAGEBOX 
#include <windows.h> 
#endif 
 
#ifndef EXIT_FAILURE		/* define exit() codes if not provided */ 
#define EXIT_FAILURE  1 
#endif 
 
 
/* 
 * Create the message string table. 
 * We do this from the master message list in jerror.h by re-reading 
 * jerror.h with a suitable definition for macro JMESSAGE. 
 * The message table is made an external symbol just in case any applications 
 * want to refer to it directly. 
 */ 
 
#ifdef NEED_SHORT_EXTERNAL_NAMES 
#define jpeg_std_message_table	jMsgTable 
#endif 
 
#define JMESSAGE(code,string)	string , 
 
const char * const jpeg_std_message_table[] = { 
#include "jerror.h" 
  NULL 
}; 
 
 
/* 
 * Error exit handler: must not return to caller. 
 * 
 * Applications may override this if they want to get control back after 
 * an error.  Typically one would longjmp somewhere instead of exiting. 
 * The setjmp buffer can be made a private field within an expanded error 
 * handler object.  Note that the info needed to generate an error message 
 * is stored in the error object, so you can generate the message now or 
 * later, at your convenience. 
 * You should make sure that the JPEG object is cleaned up (with jpeg_abort 
 * or jpeg_destroy) at some point. 
 */ 
 
METHODDEF(void) 
error_exit (j_common_ptr cinfo) 
{ 
  /* Always display the message */ 
  (*cinfo->err->output_message) (cinfo); 
 
  /* Let the memory manager delete any temp files before we die */ 
  jpeg_destroy(cinfo); 
 
  exit(EXIT_FAILURE); 
} 
 
 
/* 
 * Actual output of an error or trace message. 
 * Applications may override this method to send JPEG messages somewhere 
 * other than stderr. 
 * 
 * On Windows, printing to stderr is generally completely useless, 
 * so we provide optional code to produce an error-dialog popup. 
 * Most Windows applications will still prefer to override this routine, 
 * but if they don't, it'll do something at least marginally useful. 
 * 
 * NOTE: to use the library in an environment that doesn't support the 
 * C stdio library, you may have to delete the call to fprintf() entirely, 
 * not just not use this routine. 
 */ 
 
METHODDEF(void) 
output_message (j_common_ptr cinfo) 
{ 
  char buffer[JMSG_LENGTH_MAX]; 
 
  /* Create the message */ 
  (*cinfo->err->format_message) (cinfo, buffer); 
 
#ifdef USE_WINDOWS_MESSAGEBOX 
  /* Display it in a message dialog box */ 
  MessageBox(GetActiveWindow(), buffer, "JPEG Library Error", 
	     MB_OK | MB_ICONERROR); 
#else 
  /* Send it to stderr, adding a newline */ 
  fprintf(stderr, "%s\n", buffer); 
#endif 
} 
 
 
/* 
 * Decide whether to emit a trace or warning message. 
 * msg_level is one of: 
 *   -1: recoverable corrupt-data warning, may want to abort. 
 *    0: important advisory messages (always display to user). 
 *    1: first level of tracing detail. 
 *    2,3,...: successively more detailed tracing messages. 
 * An application might override this method if it wanted to abort on warnings 
 * or change the policy about which messages to display. 
 */ 
 
METHODDEF(void) 
emit_message (j_common_ptr cinfo, int msg_level) 
{ 
  struct jpeg_error_mgr * err = cinfo->err; 
 
  if (msg_level < 0) { 
    /* It's a warning message.  Since corrupt files may generate many warnings, 
     * the policy implemented here is to show only the first warning, 
     * unless trace_level >= 3. 
     */ 
    if (err->num_warnings == 0 || err->trace_level >= 3) 
      (*err->output_message) (cinfo); 
    /* Always count warnings in num_warnings. */ 
    err->num_warnings++; 
  } else { 
    /* It's a trace message.  Show it if trace_level >= msg_level. */ 
    if (err->trace_level >= msg_level) 
      (*err->output_message) (cinfo); 
  } 
} 
 
 
/* 
 * Format a message string for the most recent JPEG error or message. 
 * The message is stored into buffer, which should be at least JMSG_LENGTH_MAX 
 * characters.  Note that no '\n' character is added to the string. 
 * Few applications should need to override this method. 
 */ 
 
METHODDEF(void) 
format_message (j_common_ptr cinfo, char * buffer) 
{ 
  struct jpeg_error_mgr * err = cinfo->err; 
  int msg_code = err->msg_code; 
  const char * msgtext = NULL; 
  const char * msgptr; 
  char ch; 
  boolean isstring; 
 
  /* Look up message string in proper table */ 
  if (msg_code > 0 && msg_code <= err->last_jpeg_message) { 
    msgtext = err->jpeg_message_table[msg_code]; 
  } else if (err->addon_message_table != NULL && 
	     msg_code >= err->first_addon_message && 
	     msg_code <= err->last_addon_message) { 
    msgtext = err->addon_message_table[msg_code - err->first_addon_message]; 
  } 
 
  /* Defend against bogus message number */ 
  if (msgtext == NULL) { 
    err->msg_parm.i[0] = msg_code; 
    msgtext = err->jpeg_message_table[0]; 
  } 
 
  /* Check for string parameter, as indicated by %s in the message text */ 
  isstring = FALSE; 
  msgptr = msgtext; 
  while ((ch = *msgptr++) != '\0') { 
    if (ch == '%') { 
      if (*msgptr == 's') isstring = TRUE; 
      break; 
    } 
  } 
 
  /* Format the message into the passed buffer */ 
  if (isstring) 
    sprintf(buffer, msgtext, err->msg_parm.s); 
  else 
    sprintf(buffer, msgtext, 
	    err->msg_parm.i[0], err->msg_parm.i[1], 
	    err->msg_parm.i[2], err->msg_parm.i[3], 
	    err->msg_parm.i[4], err->msg_parm.i[5], 
	    err->msg_parm.i[6], err->msg_parm.i[7]); 
} 
 
 
/* 
 * Reset error state variables at start of a new image. 
 * This is called during compression startup to reset trace/error 
 * processing to default state, without losing any application-specific 
 * method pointers.  An application might possibly want to override 
 * this method if it has additional error processing state. 
 */ 
 
METHODDEF(void) 
reset_error_mgr (j_common_ptr cinfo) 
{ 
  cinfo->err->num_warnings = 0; 
  /* trace_level is not reset since it is an application-supplied parameter */ 
  cinfo->err->msg_code = 0;	/* may be useful as a flag for "no error" */ 
} 
 
 
/* 
 * Fill in the standard error-handling methods in a jpeg_error_mgr object. 
 * Typical call is: 
 *	struct jpeg_compress_struct cinfo; 
 *	struct jpeg_error_mgr err; 
 * 
 *	cinfo.err = jpeg_std_error(&err); 
 * after which the application may override some of the methods. 
 */ 
 
GLOBAL(struct jpeg_error_mgr *) 
jpeg_std_error (struct jpeg_error_mgr * err) 
{ 
  err->error_exit = error_exit; 
  err->emit_message = emit_message; 
  err->output_message = output_message; 
  err->format_message = format_message; 
  err->reset_error_mgr = reset_error_mgr; 
 
  err->trace_level = 0;		/* default = no tracing */ 
  err->num_warnings = 0;	/* no warnings emitted yet */ 
  err->msg_code = 0;		/* may be useful as a flag for "no error" */ 
 
  /* Initialize message table pointers */ 
  err->jpeg_message_table = jpeg_std_message_table; 
  err->last_jpeg_message = (int) JMSG_LASTMSGCODE - 1; 
 
  err->addon_message_table = NULL; 
  err->first_addon_message = 0;	/* for safety */ 
  err->last_addon_message = 0; 
 
  return err; 
}