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      1 /*
      2  * jerror.c
      3  *
      4  * Copyright (C) 1991-1998, Thomas G. Lane.
      5  * This file is part of the Independent JPEG Group's software.
      6  * For conditions of distribution and use, see the accompanying README file.
      7  *
      8  * This file contains simple error-reporting and trace-message routines.
      9  * These are suitable for Unix-like systems and others where writing to
     10  * stderr is the right thing to do.  Many applications will want to replace
     11  * some or all of these routines.
     12  *
     13  * If you define USE_WINDOWS_MESSAGEBOX in jconfig.h or in the makefile,
     14  * you get a Windows-specific hack to display error messages in a dialog box.
     15  * It ain't much, but it beats dropping error messages into the bit bucket,
     16  * which is what happens to output to stderr under most Windows C compilers.
     17  *
     18  * These routines are used by both the compression and decompression code.
     19  */
     20 
     21 /* this is not a core library module, so it doesn't define JPEG_INTERNALS */
     22 #include "jinclude.h"
     23 #include "jpeglib.h"
     24 #include "jversion.h"
     25 #include "jerror.h"
     26 
     27 #ifdef USE_WINDOWS_MESSAGEBOX
     28 #include <windows.h>
     29 #endif
     30 
     31 #ifndef EXIT_FAILURE		/* define exit() codes if not provided */
     32 #define EXIT_FAILURE  1
     33 #endif
     34 
     35 
     36 /*
     37  * Create the message string table.
     38  * We do this from the master message list in jerror.h by re-reading
     39  * jerror.h with a suitable definition for macro JMESSAGE.
     40  * The message table is made an external symbol just in case any applications
     41  * want to refer to it directly.
     42  */
     43 
     44 #ifdef NEED_SHORT_EXTERNAL_NAMES
     45 #define jpeg_std_message_table	jMsgTable
     46 #endif
     47 
     48 #define JMESSAGE(code,string)	string ,
     49 
     50 const char * const jpeg_std_message_table[] = {
     51 #include "jerror.h"
     52   NULL
     53 };
     54 
     55 
     56 /*
     57  * Error exit handler: must not return to caller.
     58  *
     59  * Applications may override this if they want to get control back after
     60  * an error.  Typically one would longjmp somewhere instead of exiting.
     61  * The setjmp buffer can be made a private field within an expanded error
     62  * handler object.  Note that the info needed to generate an error message
     63  * is stored in the error object, so you can generate the message now or
     64  * later, at your convenience.
     65  * You should make sure that the JPEG object is cleaned up (with jpeg_abort
     66  * or jpeg_destroy) at some point.
     67  */
     68 
     69 METHODDEF(void)
     70 error_exit (j_common_ptr cinfo)
     71 {
     72   /* Always display the message */
     73   (*cinfo->err->output_message) (cinfo);
     74 
     75   /* Let the memory manager delete any temp files before we die */
     76   jpeg_destroy(cinfo);
     77 
     78   exit(EXIT_FAILURE);
     79 }
     80 
     81 
     82 /*
     83  * Actual output of an error or trace message.
     84  * Applications may override this method to send JPEG messages somewhere
     85  * other than stderr.
     86  *
     87  * On Windows, printing to stderr is generally completely useless,
     88  * so we provide optional code to produce an error-dialog popup.
     89  * Most Windows applications will still prefer to override this routine,
     90  * but if they don't, it'll do something at least marginally useful.
     91  *
     92  * NOTE: to use the library in an environment that doesn't support the
     93  * C stdio library, you may have to delete the call to fprintf() entirely,
     94  * not just not use this routine.
     95  */
     96 
     97 METHODDEF(void)
     98 output_message (j_common_ptr cinfo)
     99 {
    100   char buffer[JMSG_LENGTH_MAX];
    101 
    102   /* Create the message */
    103   (*cinfo->err->format_message) (cinfo, buffer);
    104 
    105 #ifdef USE_WINDOWS_MESSAGEBOX
    106   /* Display it in a message dialog box */
    107   MessageBox(GetActiveWindow(), buffer, "JPEG Library Error",
    108 	     MB_OK | MB_ICONERROR);
    109 #else
    110   /* Send it to stderr, adding a newline */
    111   fprintf(stderr, "%s\n", buffer);
    112 #endif
    113 }
    114 
    115 
    116 /*
    117  * Decide whether to emit a trace or warning message.
    118  * msg_level is one of:
    119  *   -1: recoverable corrupt-data warning, may want to abort.
    120  *    0: important advisory messages (always display to user).
    121  *    1: first level of tracing detail.
    122  *    2,3,...: successively more detailed tracing messages.
    123  * An application might override this method if it wanted to abort on warnings
    124  * or change the policy about which messages to display.
    125  */
    126 
    127 METHODDEF(void)
    128 emit_message (j_common_ptr cinfo, int msg_level)
    129 {
    130   struct jpeg_error_mgr * err = cinfo->err;
    131 
    132   if (msg_level < 0) {
    133     /* It's a warning message.  Since corrupt files may generate many warnings,
    134      * the policy implemented here is to show only the first warning,
    135      * unless trace_level >= 3.
    136      */
    137     if (err->num_warnings == 0 || err->trace_level >= 3)
    138       (*err->output_message) (cinfo);
    139     /* Always count warnings in num_warnings. */
    140     err->num_warnings++;
    141   } else {
    142     /* It's a trace message.  Show it if trace_level >= msg_level. */
    143     if (err->trace_level >= msg_level)
    144       (*err->output_message) (cinfo);
    145   }
    146 }
    147 
    148 
    149 /*
    150  * Format a message string for the most recent JPEG error or message.
    151  * The message is stored into buffer, which should be at least JMSG_LENGTH_MAX
    152  * characters.  Note that no '\n' character is added to the string.
    153  * Few applications should need to override this method.
    154  */
    155 
    156 METHODDEF(void)
    157 format_message (j_common_ptr cinfo, char * buffer)
    158 {
    159   struct jpeg_error_mgr * err = cinfo->err;
    160   int msg_code = err->msg_code;
    161   const char * msgtext = NULL;
    162   const char * msgptr;
    163   char ch;
    164   boolean isstring;
    165 
    166   /* Look up message string in proper table */
    167   if (msg_code > 0 && msg_code <= err->last_jpeg_message) {
    168     msgtext = err->jpeg_message_table[msg_code];
    169   } else if (err->addon_message_table != NULL &&
    170 	     msg_code >= err->first_addon_message &&
    171 	     msg_code <= err->last_addon_message) {
    172     msgtext = err->addon_message_table[msg_code - err->first_addon_message];
    173   }
    174 
    175   /* Defend against bogus message number */
    176   if (msgtext == NULL) {
    177     err->msg_parm.i[0] = msg_code;
    178     msgtext = err->jpeg_message_table[0];
    179   }
    180 
    181   /* Check for string parameter, as indicated by %s in the message text */
    182   isstring = FALSE;
    183   msgptr = msgtext;
    184   while ((ch = *msgptr++) != '\0') {
    185     if (ch == '%') {
    186       if (*msgptr == 's') isstring = TRUE;
    187       break;
    188     }
    189   }
    190 
    191   /* Format the message into the passed buffer */
    192   if (isstring)
    193     sprintf(buffer, msgtext, err->msg_parm.s);
    194   else
    195     sprintf(buffer, msgtext,
    196 	    err->msg_parm.i[0], err->msg_parm.i[1],
    197 	    err->msg_parm.i[2], err->msg_parm.i[3],
    198 	    err->msg_parm.i[4], err->msg_parm.i[5],
    199 	    err->msg_parm.i[6], err->msg_parm.i[7]);
    200 }
    201 
    202 
    203 /*
    204  * Reset error state variables at start of a new image.
    205  * This is called during compression startup to reset trace/error
    206  * processing to default state, without losing any application-specific
    207  * method pointers.  An application might possibly want to override
    208  * this method if it has additional error processing state.
    209  */
    210 
    211 METHODDEF(void)
    212 reset_error_mgr (j_common_ptr cinfo)
    213 {
    214   cinfo->err->num_warnings = 0;
    215   /* trace_level is not reset since it is an application-supplied parameter */
    216   cinfo->err->msg_code = 0;	/* may be useful as a flag for "no error" */
    217 }
    218 
    219 
    220 /*
    221  * Fill in the standard error-handling methods in a jpeg_error_mgr object.
    222  * Typical call is:
    223  *	struct jpeg_compress_struct cinfo;
    224  *	struct jpeg_error_mgr err;
    225  *
    226  *	cinfo.err = jpeg_std_error(&err);
    227  * after which the application may override some of the methods.
    228  */
    229 
    230 GLOBAL(struct jpeg_error_mgr *)
    231 jpeg_std_error (struct jpeg_error_mgr * err)
    232 {
    233   err->error_exit = error_exit;
    234   err->emit_message = emit_message;
    235   err->output_message = output_message;
    236   err->format_message = format_message;
    237   err->reset_error_mgr = reset_error_mgr;
    238 
    239   err->trace_level = 0;		/* default = no tracing */
    240   err->num_warnings = 0;	/* no warnings emitted yet */
    241   err->msg_code = 0;		/* may be useful as a flag for "no error" */
    242 
    243   /* Initialize message table pointers */
    244   err->jpeg_message_table = jpeg_std_message_table;
    245   err->last_jpeg_message = (int) JMSG_LASTMSGCODE - 1;
    246 
    247   err->addon_message_table = NULL;
    248   err->first_addon_message = 0;	/* for safety */
    249   err->last_addon_message = 0;
    250 
    251   return err;
    252 }
    253