rev 442 - trunk

Author: giles
Date: 2005-12-05 17:47:35 -0800 (Mon, 05 Dec 2005)
New Revision: 442

Modified:
   trunk/jbig2_text.c
Log:
The SBDSOFFSET field is a *signed* 5 bit integer, so we need to sign=20
extend when reading the field to get the proper value. We now correctly
handle the 042_20.jb2 test stream.


Modified: trunk/jbig2_text.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- trunk/jbig2_text.c	2005-12-05 23:39:55 UTC (rev 441)
+++ trunk/jbig2_text.c	2005-12-06 01:47:35 UTC (rev 442)
@@ -494,6 +494,9 @@
     /* 7.4.3.1.1 */
     flags =3D jbig2_get_int16(segment_data + offset);
     offset +=3D 2;
+
+    jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number,
+	"text region header flags 0x%04x", flags);
    =20
     params.SBHUFF =3D flags & 0x0001;
     params.SBREFINE =3D flags & 0x0002;
@@ -503,9 +506,16 @@
     params.TRANSPOSED =3D flags & 0x0040;
     params.SBCOMBOP =3D (flags & 0x0180) >> 7;
     params.SBDEFPIXEL =3D flags & 0x0200;
+    /* SBDSOFFSET is a signed 5 bit integer */
     params.SBDSOFFSET =3D (flags & 0x7C00) >> 10;
+    if (params.SBDSOFFSET > 0x0f) params.SBDSOFFSET -=3D 0x20;
     params.SBRTEMPLATE =3D flags & 0x8000;
=20
+    if (params.SBDSOFFSET) {
+      jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number,
+	"text region has SBDSOFFSET %d", params.SBDSOFFSET);
+    }
+
     if (params.SBHUFF)	/* Huffman coding */
       {
         /* 7.4.3.1.2 */