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view dwt/internal/image/PngInputStream.d @ 0:380af2bdd8e5
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author | Jacob Carlborg <doob@me.com> <jacob.carlborg@gmail.com> |
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date | Sat, 09 Aug 2008 17:00:02 +0200 |
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children | 1a8b3cb347e0 |
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/******************************************************************************* * 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 java.io.IOException; import java.io.InputStream; public class PngInputStream : InputStream { PngChunkReader reader; PngChunk chunk; int offset, length; final static int DATA_OFFSET = 8; public PngInputStream(PngIdatChunk chunk, PngChunkReader reader) { this.chunk = chunk; this.reader = reader; length = chunk.getLength(); offset = 0; } private bool checkChunk() throws IOException { while (offset is length) { chunk = reader.readNextChunk(); if (chunk is null) throw new IOException(); if (chunk.getChunkType() is PngChunk.CHUNK_IEND) return false; if (chunk.getChunkType() !is PngChunk.CHUNK_IDAT) throw new IOException(); length = chunk.getLength(); offset = 0; } return true; } public void close() throws IOException { chunk = null; } public int read() throws IOException { if (chunk is null) throw new IOException(); if (offset is length && !checkChunk()) return -1; int b = chunk.reference[DATA_OFFSET + offset] & 0xFF; offset++; return b; } public int read(byte[] b, int off, int len) throws IOException { if (chunk is null) throw new IOException(); if (offset is length && !checkChunk()) return -1; len = Math.min(len, length - offset); System.arraycopy(chunk.reference, DATA_OFFSET + offset, b, off, len); offset += len; return len; } }