--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwt/internal/image/PngHuffmanTables.d	Sat Aug 09 17:00:02 2008 +0200
@@ -0,0 +1,160 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2006 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+module dwt.internal.image;
+
+import java.io.IOException;
+
+public class PngHuffmanTables {
+    PngHuffmanTable literalTable;
+    PngHuffmanTable distanceTable;
+    
+    static PngHuffmanTable FixedLiteralTable;
+    static PngHuffmanTable FixedDistanceTable;
+    
+    static final int LiteralTableSize = 288;
+    static final int[] FixedLiteralLengths = {
+        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+        9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+        9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+        9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+        9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+        9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8,
+    };
+
+    static final int DistanceTableSize = 32;
+    static final int[] FixedDistanceLengths = {
+        5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+        5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+    };
+    
+    static final int LengthCodeTableSize = 19;
+    static final int[] LengthCodeOrder = {
+        16, 17, 18, 0, 8, 7, 9, 6, 10, 5,
+        11, 4, 12, 3, 13, 2, 14, 1, 15
+    };
+    
+static PngHuffmanTables getDynamicTables(PngDecodingDataStream stream) throws IOException {
+    return new PngHuffmanTables(stream);
+}
+static PngHuffmanTables getFixedTables() {
+    return new PngHuffmanTables();
+}
+
+private PngHuffmanTable getFixedLiteralTable() {
+    if (FixedLiteralTable is null) {
+        FixedLiteralTable = new PngHuffmanTable(FixedLiteralLengths);
+    }
+    return FixedLiteralTable;
+}
+
+private PngHuffmanTable getFixedDistanceTable() {
+    if (FixedDistanceTable is null) {
+        FixedDistanceTable = new PngHuffmanTable(FixedDistanceLengths);
+    }
+    return FixedDistanceTable;
+}
+
+private PngHuffmanTables () {
+    literalTable = getFixedLiteralTable();
+    distanceTable = getFixedDistanceTable();
+}
+
+private PngHuffmanTables (PngDecodingDataStream stream) throws IOException {
+    int literals = PngLzBlockReader.FIRST_LENGTH_CODE 
+        + stream.getNextIdatBits(5);
+    int distances = PngLzBlockReader.FIRST_DISTANCE_CODE 
+        + stream.getNextIdatBits(5);
+    int codeLengthCodes = PngLzBlockReader.FIRST_CODE_LENGTH_CODE 
+        + stream.getNextIdatBits(4);
+
+    if (codeLengthCodes > PngLzBlockReader.LAST_CODE_LENGTH_CODE) {
+        stream.error();
+    }
+    
+    /* Tricky, tricky, tricky. The length codes are stored in
+     * a very odd order. (For the order, see the definition of
+     * the static field lengthCodeOrder.) Also, the data may 
+     * not contain values for all the codes. It may just contain 
+     * values for the first X number of codes. The table should
+     * be of size <LengthCodeTableSize> regardless of the number
+     * of values actually given in the table.
+     */ 
+    int[] lengthCodes = new int[LengthCodeTableSize];
+    for (int i = 0; i < codeLengthCodes; i++) {
+        lengthCodes[LengthCodeOrder[i]] = stream.getNextIdatBits(3);
+    }
+    PngHuffmanTable codeLengthsTable = new PngHuffmanTable(lengthCodes);
+    
+    int[] literalLengths = readLengths(
+        stream, literals, codeLengthsTable, LiteralTableSize);
+    int[] distanceLengths = readLengths(
+        stream, distances, codeLengthsTable, DistanceTableSize);
+    
+    literalTable = new PngHuffmanTable(literalLengths);
+    distanceTable = new PngHuffmanTable(distanceLengths);
+}
+
+private int [] readLengths (PngDecodingDataStream stream, 
+    int numLengths, 
+    PngHuffmanTable lengthsTable,
+    int tableSize) throws IOException
+{
+    int[] lengths = new int[tableSize];
+    
+    for (int index = 0; index < numLengths;) {
+        int value = lengthsTable.getNextValue(stream);
+        if (value < 16) {
+            // Literal value
+            lengths[index] = value;
+            index++;
+        } else if (value is 16) {
+            // Repeat the previous code 3-6 times.
+            int count = stream.getNextIdatBits(2) + 3;
+            for (int i = 0; i < count; i++) {
+                lengths[index] = lengths [index - 1];
+                index++;
+            }
+        } else if (value is 17) {
+            // Repeat 0 3-10 times.
+            int count = stream.getNextIdatBits(3) + 3;
+            for (int i = 0; i < count; i++) {
+                lengths[index] = 0;
+                index++;
+            }
+        } else if (value is 18) {
+            // Repeat 0 11-138 times.
+            int count = stream.getNextIdatBits(7) + 11;
+            for (int i = 0; i < count; i++) {
+                lengths[index] = 0;
+                index++;
+            }
+        } else {
+            stream.error();
+        }
+    }
+    return lengths;
+}
+
+int getNextLiteralValue(PngDecodingDataStream stream) throws IOException {
+    return literalTable.getNextValue(stream);
+}
+
+int getNextDistanceValue(PngDecodingDataStream stream) throws IOException {
+    return distanceTable.getNextValue(stream);
+}
+
+}