JBIG2-Image-Decoder

This project fix bug in MMR decoding in Borisvl/JBIG2-Image-Decoder's fork JPedal's JBIG2 library.

Description

A pdf file (version 1.4) produced by Xerox WorkCentre 5230(A) with JBIG2 compression (MMR) give an error, when attept to decode an image stream from this file:

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 30447
    at org.jpedal.jbig2.io.StreamReader.readByte(StreamReader.java:86)
    at org.jpedal.jbig2.decoders.JBIG2StreamDecoder.handleSegmentReferredToCountAndRententionFlags(JBIG2StreamDecoder.java:503)
    at org.jpedal.jbig2.decoders.JBIG2StreamDecoder.readSegmentHeader(JBIG2StreamDecoder.java:457)
    at org.jpedal.jbig2.decoders.JBIG2StreamDecoder.readSegments(JBIG2StreamDecoder.java:211)
    at org.jpedal.jbig2.decoders.JBIG2StreamDecoder.decodeJBIG2(JBIG2StreamDecoder.java:173)
    at org.jpedal.jbig2.JBIG2Decoder.decodeJBIG2(JBIG2Decoder.java:148)
    at org.jpedal.jbig2.JBIG2Decoder.decodeJBIG2(JBIG2Decoder.java:123)
    at org.jpedal.jbig2.JBIG2Decoder.decodeJBIG2(JBIG2Decoder.java:108)
    at org.jpedal.jbig2.JBIG2Decoder.decodeJBIG2(JBIG2Decoder.java:98)
    at org.jpedal.jbig2.examples.viewer.JBIG2Viewer.openFile(JBIG2Viewer.java:274)
    at org.jpedal.jbig2.examples.viewer.JBIG2Viewer.access$0(JBIG2Viewer.java:252)
    at org.jpedal.jbig2.examples.viewer.JBIG2Viewer$1.actionPerformed(JBIG2Viewer.java:163)
    at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
    at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
    at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
    at java.awt.Component.processMouseEvent(Unknown Source)
    at javax.swing.JComponent.processMouseEvent(Unknown Source)
    at java.awt.Component.processEvent(Unknown Source)
    at java.awt.Container.processEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Window.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$200(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

Reason

I think the reason in the 6.2.6 Decoding using MMR coding of JBIG2 specification.

If MMR is 1, the generic region decoding procedure is identical to an MMR (ModifiedModified READ) decoder described in ITU-T Recommendation T.6, with the following exceptions: � An invocation of the generic region decoding procedure with MMR equal to 1 shall consume an integral number of bytes, beginning and ending on a byte boundary. This may involve skipping over some bits in the last byte read.

Correct me if I wrong...

Fix

//GenericRegionSegment.java
//bitmap.readBitmap(useMMR, template, typicalPredictionGenericDecodingOn, false, null, genericBAdaptiveTemplateX, genericBAdaptiveTemplateY, useMMR ? 0 : length - 18);
bitmap.readBitmap(useMMR, template, typicalPredictionGenericDecodingOn, false, null, genericBAdaptiveTemplateX, genericBAdaptiveTemplateY, useMMR ? bytesRead : length - 18);