    /*
     * 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;
      int 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;
    }