TMI-84: LZWDecoder fixes for > 12 bit exception when using full 12 bit (4096 entries) table

common/common-io/src/main/java/com/twelvemonkeys/io/enc/Decoder.java

@@ -57,9 +57,10 @@ public interface Decoder {
      * @return the total number of bytes read into the buffer, or {@code 0}
      * if there is no more data because the end of the stream has been reached.
      *
-     * @throws DecodeException if encoded data is corrupt
-     * @throws IOException if an I/O error occurs
-     * @throws java.io.EOFException if a premature end-of-file is encountered
+     * @throws DecodeException if encoded data is corrupt.
+     * @throws IOException if an I/O error occurs.
+     * @throws java.io.EOFException if a premature end-of-file is encountered.
+     * @throws java.lang.NullPointerException if either argument is {@code null}.
      */
     int decode(InputStream stream, ByteBuffer buffer) throws IOException;
 }

imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/LZWDecoder.java

@@ -33,12 +33,11 @@ import com.twelvemonkeys.io.enc.Decoder;
 
 import java.io.IOException;
 import java.io.InputStream;
-import java.lang.String;
 import java.nio.ByteBuffer;
 
 /**
- * Lempel–Ziv–Welch (LZW) decompression. LZW is a universal loss-less data compression algorithm
- * created by Abraham Lempel, Jacob Ziv, and Terry Welch.
+ * Lempel–Ziv–Welch (LZW) decompression.
+ * LZW is a universal loss-less data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch.
  * Inspired by libTiff's LZW decompression.
  *
  * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
@@ -57,8 +56,6 @@ abstract class LZWDecoder implements Decoder {
 
     private static final int TABLE_SIZE = 1 << MAX_BITS;
 
-    private final boolean compatibilityMode;
-
     private final LZWString[] table;
     private int tableLength;
     int bitsPerCode;
@@ -70,11 +67,8 @@ abstract class LZWDecoder implements Decoder {
     int nextData;
     int nextBits;
 
-
-    protected LZWDecoder(final boolean compatibilityMode) {
-        this.compatibilityMode = compatibilityMode;
-
-        table = new LZWString[compatibilityMode ? TABLE_SIZE + 1024 : TABLE_SIZE]; // libTiff adds 1024 "for compatibility"...
+    protected LZWDecoder(int tableSize) {
+        table = new LZWString[tableSize];
 
         // First 258 entries of table is always fixed
         for (int i = 0; i < 256; i++) {
@@ -97,6 +91,10 @@ abstract class LZWDecoder implements Decoder {
     }
 
     public int decode(final InputStream stream, final ByteBuffer buffer) throws IOException {
+        if (buffer == null) {
+            throw new NullPointerException("buffer == null"); // As per contract
+        }
+
         // Adapted from the pseudo-code example found in the TIFF 6.0 Specification, 1992.
         // See Section 13: "LZW Compression"/"LZW Decoding", page 61+
         int code;
@@ -114,8 +112,7 @@ abstract class LZWDecoder implements Decoder {
             }
             else {
                 if (table[oldCode] == null) {
-                    System.err.println("tableLength: " + tableLength);
-                    System.err.println("oldCode: " + oldCode);
+                    throw new DecodeException(String.format("Corrupted TIFF LZW: code %d (table size: %d)", oldCode, tableLength));
                 }
 
                 if (isInTable(code)) {
@@ -133,7 +130,7 @@ abstract class LZWDecoder implements Decoder {
             oldCode = code;
 
             if (buffer.remaining() < maxString + 1) {
-                // Buffer full, stop decoding for now
+                // Buffer (almost) full, stop decoding for now
                 break;
             }
         }
@@ -142,18 +139,18 @@ abstract class LZWDecoder implements Decoder {
     }
 
     private void addStringToTable(final LZWString string) throws IOException {
+        if (tableLength > table.length) {
+            throw new DecodeException(String.format("TIFF LZW with more than %d bits per code encountered (table overflow)", MAX_BITS));
+        }
+
         table[tableLength++] = string;
 
         if (tableLength > maxCode) {
             bitsPerCode++;
 
             if (bitsPerCode > MAX_BITS) {
-                if (compatibilityMode) {
-                    bitsPerCode--;
-                }
-                else {
-                    throw new DecodeException(String.format("TIFF LZW with more than %d bits per code encountered (table overflow)", MAX_BITS));
-                }
+                // Continue reading MAX_BITS (12 bit) length codes
+                bitsPerCode = MAX_BITS;
             }
 
             bitMask = bitmaskFor(bitsPerCode);
@@ -173,9 +170,9 @@ abstract class LZWDecoder implements Decoder {
 
     protected abstract int getNextCode(final InputStream stream) throws IOException;
 
-
     static boolean isOldBitReversedStream(final InputStream stream) throws IOException {
         stream.mark(2);
+
         try {
             int one = stream.read();
             int two = stream.read();
@@ -191,10 +188,10 @@ abstract class LZWDecoder implements Decoder {
         return oldBitReversedStream ? new LZWCompatibilityDecoder() : new LZWSpecDecoder();
     }
 
-    private static final class LZWSpecDecoder extends LZWDecoder {
+    static final class LZWSpecDecoder extends LZWDecoder {
 
         protected LZWSpecDecoder() {
-            super(false);
+            super(TABLE_SIZE);
         }
 
         @Override
@@ -243,7 +240,7 @@ abstract class LZWDecoder implements Decoder {
         // compressed data will be identical whether it is an ‘II’ or ‘MM’ file."
 
         protected LZWCompatibilityDecoder() {
-            super(true);
+            super(TABLE_SIZE + 1024); // libTiff adds 1024 "for compatibility", this value seems to work fine...
         }
 
         @Override

imageio/imageio-tiff/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/TIFFImageReaderTest.java

@@ -30,7 +30,6 @@ import com.twelvemonkeys.imageio.util.ImageReaderAbstractTestCase;
 import org.junit.Test;
 
 import javax.imageio.ImageReadParam;
-import javax.imageio.ImageReader;
 import javax.imageio.event.IIOReadWarningListener;
 import javax.imageio.spi.ImageReaderSpi;
 import javax.imageio.stream.ImageInputStream;
@@ -42,12 +41,9 @@ import java.util.List;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
-import static org.mockito.Matchers.anyString;
 import static org.mockito.Matchers.contains;
 import static org.mockito.Matchers.eq;
-import static org.mockito.Mockito.atLeastOnce;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.*;
 
 /**
  * TIFFImageReaderTest
@@ -72,6 +68,7 @@ public class TIFFImageReaderTest extends ImageReaderAbstractTestCase<TIFFImageRe
                 new TestData(getClassLoaderResource("/tiff/bali.tif"), new Dimension(725, 489)), // Palette-based, LZW compressed
                 new TestData(getClassLoaderResource("/tiff/f14.tif"), new Dimension(640, 480)), // Gray, uncompressed
                 new TestData(getClassLoaderResource("/tiff/marbles.tif"), new Dimension(1419, 1001)), // RGB, LZW compressed w/predictor
+                new TestData(getClassLoaderResource("/tiff/lzw-full-12-bit-table.tif"), new Dimension(874, 1240)), // Gray, LZW compressed, w/predictor
                 new TestData(getClassLoaderResource("/tiff/chifley_logo.tif"), new Dimension(591, 177)), // CMYK, uncompressed
                 new TestData(getClassLoaderResource("/tiff/ycbcr-cat.tif"), new Dimension(250, 325)), // YCbCr, LZW compressed
                 new TestData(getClassLoaderResource("/tiff/quad-jpeg.tif"), new Dimension(512, 384)), // YCbCr, JPEG compressed, striped