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SWT is an open source widget toolkit for Java designed to provide efficient, portable access to the user-interface facilities of the operating systems on which it is implemented.
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/*******************************************************************************
* Copyright (c) 2000, 2011 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
*******************************************************************************/
package org.eclipse.swt.internal.image;
import org.eclipse.swt.*;
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 == null) {
try {
PngChunk chunk = PngChunk.readNextFromStream(inputStream);
if (chunk == null) SWT.error(SWT.ERROR_INVALID_IMAGE);
headerChunk = (PngIhdrChunk) chunk;
headerChunk.validate(readState, null);
} catch (ClassCastException e) {
SWT.error(SWT.ERROR_INVALID_IMAGE);
}
}
return headerChunk;
}
PngChunk readNextChunk() {
if (headerChunk == null) return getIhdrChunk();
PngChunk chunk = PngChunk.readNextFromStream(inputStream);
if (chunk == null) SWT.error(SWT.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() == PngChunk.CHUNK_IDAT)) {
readState.readPixelData = true;
}
return chunk;
}
boolean readPixelData() {
return readState.readPixelData;
}
boolean hasMoreChunks() {
return !readState.readIEND;
}
}