--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwt/internal/image/PngChunkReader.d	Sat Aug 09 17:00:02 2008 +0200
@@ -0,0 +1,72 @@
+/*******************************************************************************
+ * 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 dwt.DWT;
+
+public class PngChunkReader {
+    LEDataInputStream inputStream;
+    PngFileReadState readState;
+    PngIhdrChunk headerChunk;
+    PngPlteChunk paletteChunk;
+    
+PngChunkReader(LEDataInputStream inputStream) {
+    this.inputStream = inputStream;
+    readState = new PngFileReadState();
+    headerChunk = null;
+}
+
+PngIhdrChunk getIhdrChunk() {
+    if (headerChunk is null) {
+        try { 
+            PngChunk chunk = PngChunk.readNextFromStream(inputStream);
+            if (chunk is null) DWT.error(DWT.ERROR_INVALID_IMAGE);
+            headerChunk = (PngIhdrChunk) chunk;
+            headerChunk.validate(readState, null);
+        } catch (ClassCastException e) {
+            DWT.error(DWT.ERROR_INVALID_IMAGE);
+        }
+    }
+    return headerChunk;
+}
+
+PngChunk readNextChunk() {
+    if (headerChunk is null) return getIhdrChunk();
+    
+    PngChunk chunk = PngChunk.readNextFromStream(inputStream);
+    if (chunk is null) DWT.error(DWT.ERROR_INVALID_IMAGE);
+    switch (chunk.getChunkType()) {
+        case PngChunk.CHUNK_tRNS:
+            ((PngTrnsChunk) chunk).validate(readState, headerChunk, paletteChunk);
+            break;
+        case PngChunk.CHUNK_PLTE:
+            chunk.validate(readState, headerChunk);
+            paletteChunk = (PngPlteChunk) chunk;
+            break;
+        default:
+            chunk.validate(readState, headerChunk);
+    }
+    if (readState.readIDAT && !(chunk.getChunkType() is PngChunk.CHUNK_IDAT)) {
+        readState.readPixelData = true;
+    }
+    return chunk;
+}
+
+bool readPixelData() {
+    return readState.readPixelData;
+}
+
+bool hasMoreChunks() {
+    return !readState.readIEND;
+}
+
+}