Fixed DCX off-by one issue + minor optimization.

imageio/imageio-pcx/src/main/java/com/twelvemonkeys/imageio/plugins/dcx/DCXHeader.java

@@ -65,16 +65,16 @@ final class DCXHeader {
         int count = 0;
         do {
             offsets[count] = imageInput.readInt();
-            count++;
         }
-        while (offsets[count - 1] != 0 && count < offsets.length);
+        while (offsets[count] != 0 && count++ < offsets.length);
 
         return new DCXHeader(count == offsets.length ? offsets : Arrays.copyOf(offsets, count));
     }
 
-    @Override public String toString() {
+    @Override
-        return "DCXHeader{" +
+    public String toString() {
+        return "DCXHeader[" +
                 "offsetTable=" + Arrays.toString(offsetTable) +
-                '}';
+                ']';
     }
 }

imageio/imageio-pcx/src/main/java/com/twelvemonkeys/imageio/plugins/dcx/DCXImageReader.java

@@ -42,7 +42,6 @@ import javax.imageio.event.IIOReadWarningListener;
 import javax.imageio.metadata.IIOMetadata;
 import javax.imageio.metadata.IIOMetadataFormatImpl;
 import javax.imageio.spi.ImageReaderSpi;
-import java.awt.*;
 import java.awt.image.BufferedImage;
 import java.io.File;
 import java.io.IOException;
@@ -50,14 +49,16 @@ import java.nio.ByteOrder;
 import java.util.Iterator;
 
 public final class DCXImageReader extends ImageReaderBase {
-    // TODO: Delegate listeners with correct index!
+
+    final static boolean DEBUG = "true".equalsIgnoreCase(System.getProperty("com.twelvemonkeys.imageio.plugins.dcx.debug"));
 
     private DCXHeader header;
 
+    private int index = -1;
     private PCXImageReader readerDelegate;
     private ProgressDelegator progressDelegator;
 
-    public DCXImageReader(final ImageReaderSpi provider) {
+    DCXImageReader(final ImageReaderSpi provider) {
         super(provider);
         readerDelegate = new PCXImageReader(provider);
 
@@ -70,62 +71,73 @@ public final class DCXImageReader extends ImageReaderBase {
         readerDelegate.addIIOReadWarningListener(progressDelegator);
     }
 
-    @Override protected void resetMembers() {
+    @Override
+    protected void resetMembers() {
         header = null;
 
+        index = -1;
         readerDelegate.reset();
         installListeners();
     }
 
-    @Override public void dispose() {
+    @Override
+    public void dispose() {
         super.dispose();
 
         readerDelegate.dispose();
         readerDelegate = null;
     }
 
-    @Override public int getWidth(final int imageIndex) throws IOException {
+    @Override
+    public int getWidth(final int imageIndex) throws IOException {
         initIndex(imageIndex);
 
         return readerDelegate.getWidth(0);
     }
 
-    @Override public int getHeight(final int imageIndex) throws IOException {
+    @Override
+    public int getHeight(final int imageIndex) throws IOException {
         initIndex(imageIndex);
 
         return readerDelegate.getHeight(0);
     }
 
-    @Override public ImageTypeSpecifier getRawImageType(final int imageIndex) throws IOException {
+    @Override
+    public ImageTypeSpecifier getRawImageType(final int imageIndex) throws IOException {
         initIndex(imageIndex);
 
         return readerDelegate.getRawImageType(0);
     }
 
-    @Override public Iterator<ImageTypeSpecifier> getImageTypes(final int imageIndex) throws IOException {
+    @Override
+    public Iterator<ImageTypeSpecifier> getImageTypes(final int imageIndex) throws IOException {
         initIndex(imageIndex);
 
         return readerDelegate.getImageTypes(0);
     }
 
-    @Override public BufferedImage read(final int imageIndex, final ImageReadParam param) throws IOException {
+    @Override
+    public BufferedImage read(final int imageIndex, final ImageReadParam param) throws IOException {
         initIndex(imageIndex);
 
         return readerDelegate.read(imageIndex, param);
     }
 
-    @Override public IIOMetadata getImageMetadata(final int imageIndex) throws IOException {
+    @Override
+    public IIOMetadata getImageMetadata(final int imageIndex) throws IOException {
         initIndex(imageIndex);
 
         return readerDelegate.getImageMetadata(0);
     }
 
-    @Override public synchronized void abort() {
+    @Override
+    public synchronized void abort() {
         super.abort();
         readerDelegate.abort();
     }
 
-    @Override public int getNumImages(final boolean allowSearch) throws IOException {
+    @Override
+    public int getNumImages(final boolean allowSearch) throws IOException {
         readHeader();
 
         return header.getCount();
@@ -134,10 +146,12 @@ public final class DCXImageReader extends ImageReaderBase {
     private void initIndex(final int imageIndex) throws IOException {
         checkBounds(imageIndex);
 
+        if (index != imageIndex) {
             imageInput.seek(header.getOffset(imageIndex));
-        progressDelegator.index = imageIndex;
+            index = imageIndex;
             readerDelegate.setInput(new SubImageInputStream(imageInput, Long.MAX_VALUE));
         }
+    }
 
     private void readHeader() throws IOException {
         assertInput();
@@ -145,7 +159,11 @@ public final class DCXImageReader extends ImageReaderBase {
         if (header == null) {
             imageInput.setByteOrder(ByteOrder.LITTLE_ENDIAN);
             header = DCXHeader.read(imageInput);
-//            System.err.println("header: " + header);
+
+            if (DEBUG) {
+                System.err.println("header: " + header);
+            }
+
             imageInput.flushBefore(imageInput.getStreamPosition());
         }
 
@@ -153,8 +171,6 @@ public final class DCXImageReader extends ImageReaderBase {
     }
 
     private class ProgressDelegator extends ProgressListenerBase implements IIOReadWarningListener {
-        private int index;
-
         @Override
         public void imageComplete(ImageReader source) {
             processImageComplete();
@@ -190,7 +206,6 @@ public final class DCXImageReader extends ImageReaderBase {
         }
     }
 
-
     public static void main(String[] args) throws IOException {
         DCXImageReader reader = new DCXImageReader(null);
 

imageio/imageio-pcx/src/main/java/com/twelvemonkeys/imageio/plugins/dcx/DCXImageReaderSpi.java

@@ -45,7 +45,8 @@ public final class DCXImageReaderSpi extends ImageReaderSpiBase {
         super(new DCXProviderInfo());
     }
 
-    @Override public boolean canDecodeInput(final Object source) throws IOException {
+    @Override
+    public boolean canDecodeInput(final Object source) throws IOException {
         if (!(source instanceof ImageInputStream)) {
             return false;
         }
@@ -69,10 +70,13 @@ public final class DCXImageReaderSpi extends ImageReaderSpiBase {
         }
     }
 
-    @Override public ImageReader createReaderInstance(final Object extension) throws IOException {
+    @Override
+    public ImageReader createReaderInstance(final Object extension) throws IOException {
         return new DCXImageReader(this);
     }
 
-    @Override public String getDescription(final Locale locale) {
+    @Override
+    public String getDescription(final Locale locale) {
         return "Multi-page PCX fax document (DCX) image reader";
-    }}
+    }
+}

imageio/imageio-pcx/src/test/java/com/twelvemonkeys/imageio/plugins/dcx/DCXImageReaderTest.java

@@ -29,13 +29,21 @@
 package com.twelvemonkeys.imageio.plugins.dcx;
 
 import com.twelvemonkeys.imageio.util.ImageReaderAbstractTest;
+import org.junit.Test;
 
+import javax.imageio.ImageIO;
 import javax.imageio.spi.ImageReaderSpi;
+import javax.imageio.stream.ImageInputStream;
 import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
 /**
  * DCXImageReaderTest
  *
@@ -82,4 +90,20 @@ public class DCXImageReaderTest extends ImageReaderAbstractTest<DCXImageReader>
                 "image/dcx", "image/x-dcx"
         );
     }
+
+    @Test
+    public void testCount() throws IOException {
+        try (ImageInputStream input = ImageIO.createImageInputStream(getClassLoaderResource("/dcx/input.dcx"))) {
+            DCXImageReader reader = createReader();
+            reader.setInput(input);
+
+            assertEquals(1, reader.getNumImages(true));
+            assertEquals(70, reader.getWidth(0));
+            assertEquals(46, reader.getHeight(0));
+
+            BufferedImage image = reader.read(0);
+
+            assertNotNull(image);
+        }
+    }
 }