diff org.eclipse.swt.win32.win32.x86/src/org/eclipse/swt/internal/image/PngDecodingDataStream.d @ 0:6dd524f61e62

add dwt win and basic java stuff
author Frank Benoit <benoit@tionex.de>
date Mon, 02 Mar 2009 14:44:16 +0100
parents
children d46287db17ed
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/org.eclipse.swt.win32.win32.x86/src/org/eclipse/swt/internal/image/PngDecodingDataStream.d	Mon Mar 02 14:44:16 2009 +0100
@@ -0,0 +1,141 @@
+/*******************************************************************************
+ * 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
+ * Port to the D programming language:
+ *     Frank Benoit <benoit@tionex.de>
+ *******************************************************************************/
+module org.eclipse.swt.internal.image.PngDecodingDataStream;
+
+
+import java.io.InputStream;
+
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.internal.image.PngLzBlockReader;
+
+public class PngDecodingDataStream : InputStream {
+
+    alias InputStream.read read;
+
+    InputStream stream;
+    byte currentByte;
+    int nextBitIndex;
+
+    PngLzBlockReader lzBlockReader;
+    int adlerValue;
+
+    static final int PRIME = 65521;
+    static final int MAX_BIT = 7;
+
+this(InputStream stream) {
+    super();
+    this.stream = stream;
+    nextBitIndex = MAX_BIT + 1;
+    adlerValue = 1;
+    lzBlockReader = new PngLzBlockReader(this);
+    readCompressedDataHeader();
+    lzBlockReader.readNextBlockHeader();
+}
+
+/**
+ * This method should be called when the image decoder thinks
+ * that all of the compressed image data has been read. This
+ * method will ensure that the next data value is an end of
+ * block marker. If there are more blocks after this one,
+ * the method will read them and ensure that they are empty.
+ */
+void assertImageDataAtEnd() {
+    lzBlockReader.assertCompressedDataAtEnd();
+}
+
+public override void close() {
+    assertImageDataAtEnd();
+    checkAdler();
+}
+
+int getNextIdatBits(int length) {
+    int value = 0;
+    for (int i = 0; i < length; i++) {
+        value |= (getNextIdatBit() << i);
+    }
+    return value;
+}
+
+int getNextIdatBit() {
+    if (nextBitIndex > MAX_BIT) {
+        currentByte = getNextIdatByte();
+        nextBitIndex = 0;
+    }
+    return (currentByte & (1 << nextBitIndex)) >> nextBitIndex++;
+}
+
+byte getNextIdatByte() {
+    byte nextByte = cast(byte)stream.read();
+    nextBitIndex = MAX_BIT + 1;
+    return nextByte;
+}
+
+void updateAdler(byte value) {
+    int low = adlerValue & 0xFFFF;
+    int high = (adlerValue >> 16) & 0xFFFF;
+    int valueInt = value & 0xFF;
+    low = (low + valueInt) % PRIME;
+    high = (low + high) % PRIME;
+    adlerValue = (high << 16) | low;
+}
+
+public override int read() {
+    byte nextDecodedByte = lzBlockReader.getNextByte();
+    updateAdler(nextDecodedByte);
+    return nextDecodedByte & 0xFF;
+}
+
+public override int read(byte[] buffer, int off, int len) {
+    for (int i = 0; i < len; i++) {
+        int b = read();
+        if (b is -1) return i;
+        buffer[off + i] = cast(byte)b;
+    }
+    return len;
+}
+
+void error() {
+    SWT.error(SWT.ERROR_INVALID_IMAGE);
+}
+
+private void readCompressedDataHeader() {
+    byte headerByte1 = getNextIdatByte();
+    byte headerByte2 = getNextIdatByte();
+
+    int number = ((headerByte1 & 0xFF) << 8) | (headerByte2 & 0xFF);
+    if (number % 31 !is 0) error();
+
+    int compressionMethod = headerByte1 & 0x0F;
+    if (compressionMethod !is 8) error();
+
+    int windowSizeHint = (headerByte1 & 0xF0) >> 4;
+    if (windowSizeHint > 7) error();
+    int windowSize = (1 << (windowSizeHint + 8));
+    lzBlockReader.setWindowSize(windowSize);
+
+    int dictionary = (headerByte2 & (1 << 5));
+    if (dictionary !is 0) error();
+
+//  int compressionLevel = (headerByte2 & 0xC0) >> 6;
+}
+
+void checkAdler() {
+    int storedAdler = 0;
+    storedAdler |= ((getNextIdatByte() & 0xFF) << 24);
+    storedAdler |= ((getNextIdatByte() & 0xFF) << 16);
+    storedAdler |= ((getNextIdatByte() & 0xFF) << 8);
+    storedAdler |=  (getNextIdatByte() & 0xFF);
+    if (storedAdler !is adlerValue) error();
+}
+
+}