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complain if the file uses the 'random access' layout which we don't handle yet.


git-svn-id: http://svn.ghostscript.com/jbig2dec/trunk@29 ded80894-8fb9-0310-811b-c03f3676ab4d

--- a/jbig2dec.c

+++ b/jbig2dec.c

@@ -8,7 +8,7 @@

     the Free Software Foundation; either version 2 of the License, or

     (at your option) any later version.

-    $Id: jbig2dec.c,v 1.7 2001/06/14 08:25:01 giles Exp $

+    $Id: jbig2dec.c,v 1.8 2001/06/14 23:09:23 giles Exp $

 */

 #include <stdio.h>

@@ -21,14 +21,20 @@

 typedef struct _Jbig2SymbolDictionary Jbig2SymbolDictionary;

 typedef struct _Jbig2PageInfo Jbig2PageInfo;

+/* our main 'context' structure for decoding a jbig2 bitstream */

 struct _Jbig2Ctx {

   FILE *f;

   int offset;

-

-  byte flags;

+  

   int32 n_pages;

+  byte flags;

 };

+/* useful masks for parsing the flags field */

+#define JBIG2_FILE_FLAGS_SEQUENTIAL_ACCESS	0x01

+#define JBIG2_FILE_FLAGS_PAGECOUNT_UNKNOWN	0x02

+

+

 struct _Jbig2SegmentHeader {

   int32 segment_number;

   byte flags;

@@ -105,7 +111,7 @@

       return NULL;

     }

   ctx->flags = buf[8];

-  if (ctx->flags & 2)

+  if (ctx->flags & JBIG2_FILE_FLAGS_PAGECOUNT_UNKNOWN)

     {

       ctx->offset = 9;	/* number of pages unknown */

 	  ctx->n_pages = 0;

@@ -115,6 +121,14 @@

       ctx->offset = 13;

       ctx->n_pages = get_int32 (ctx, 9);

 	}

+  

+  if(!ctx->flags & JBIG2_FILE_FLAGS_SEQUENTIAL_ACCESS) {

+	printf("warning: random access header organization.\n");

+	printf("we don't handle that yet.\n");

+	free(ctx);

+	return NULL;

+  }

+	

   return ctx;

 }