| /******************************************************************************* |
| * 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.*; |
| |
| class PngIdatChunk extends PngChunk { |
| |
| static final int HEADER_BYTES_LENGTH = 2; |
| static final int ADLER_FIELD_LENGTH = 4; |
| static final int HEADER_BYTE1_DATA_OFFSET = DATA_OFFSET + 0; |
| static final int HEADER_BYTE2_DATA_OFFSET = DATA_OFFSET + 1; |
| static final int ADLER_DATA_OFFSET = DATA_OFFSET + 2; // plus variable compressed data length |
| |
| PngIdatChunk(byte headerByte1, byte headerByte2, byte[] data, int adler) { |
| super(data.length + HEADER_BYTES_LENGTH + ADLER_FIELD_LENGTH); |
| setType(TYPE_IDAT); |
| reference[HEADER_BYTE1_DATA_OFFSET] = headerByte1; |
| reference[HEADER_BYTE2_DATA_OFFSET] = headerByte2; |
| System.arraycopy(data, 0, reference, DATA_OFFSET, data.length); |
| setInt32(ADLER_DATA_OFFSET, adler); |
| setCRC(computeCRC()); |
| } |
| |
| PngIdatChunk(byte[] reference) { |
| super(reference); |
| } |
| |
| int getChunkType() { |
| return CHUNK_IDAT; |
| } |
| |
| /** |
| * Answer whether the chunk is a valid IDAT chunk. |
| */ |
| void validate(PngFileReadState readState, PngIhdrChunk headerChunk) { |
| if (!readState.readIHDR |
| || (headerChunk.getMustHavePalette() && !readState.readPLTE) |
| || readState.readIEND) |
| { |
| SWT.error(SWT.ERROR_INVALID_IMAGE); |
| } else { |
| readState.readIDAT = true; |
| } |
| |
| super.validate(readState, headerChunk); |
| } |
| |
| byte getDataByteAtOffset(int offset) { |
| return reference[DATA_OFFSET + offset]; |
| } |
| |
| } |