| /******************************************************************************* |
| * 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 |
| *******************************************************************************/ |
| 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; |
| } |
| |
| } |