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1 /*******************************************************************************
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2 * Copyright (c) 2000, 2006 IBM Corporation and others.
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3 * All rights reserved. This program and the accompanying materials
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4 * are made available under the terms of the Eclipse Public License v1.0
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5 * which accompanies this distribution, and is available at
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6 * http://www.eclipse.org/legal/epl-v10.html
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7 *
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8 * Contributors:
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9 * IBM Corporation - initial API and implementation
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10 * Port to the D programming language:
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11 * Frank Benoit <benoit@tionex.de>
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12 *******************************************************************************/
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13 module org.eclipse.swt.internal.image.PngInputStream;
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14
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15 import java.lang.all;
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16
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17 import java.io.InputStream;
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18 import org.eclipse.swt.internal.image.PngIdatChunk;
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19 import org.eclipse.swt.internal.image.PngChunkReader;
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20 import org.eclipse.swt.internal.image.PngChunk;
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21
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22
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23 public class PngInputStream : InputStream {
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24
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25 alias InputStream.read read;
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26
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27 PngChunkReader reader;
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28 PngChunk chunk;
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29 int offset, length;
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30
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31 final static int DATA_OFFSET = 8;
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32
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33 public this(PngIdatChunk chunk, PngChunkReader reader) {
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34 this.chunk = chunk;
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35 this.reader = reader;
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36 length = chunk.getLength();
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37 offset = 0;
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38 }
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39
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40 private bool checkChunk() {
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41 while (offset is length) {
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42 chunk = reader.readNextChunk();
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43 if (chunk is null) throw new IOException("no data");
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44 if (chunk.getChunkType() is PngChunk.CHUNK_IEND) return false;
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45 if (chunk.getChunkType() !is PngChunk.CHUNK_IDAT) throw new IOException("");
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46 length = chunk.getLength();
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47 offset = 0;
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48 }
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49 return true;
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50 }
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51
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52 public override void close() {
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53 chunk = null;
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54 }
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55
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56 public override int read() {
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57 if (chunk is null) throw new IOException("");
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58 if (offset is length && !checkChunk()) return -1;
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59 int b = chunk.reference[DATA_OFFSET + offset] & 0xFF;
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60 offset++;
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61 return b;
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62 }
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63
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64 public override int read(byte[] b, int off, int len) {
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65 if (chunk is null) throw new IOException("");
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66 if (offset is length && !checkChunk()) return -1;
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67 len = Math.min(len, length - offset);
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68 System.arraycopy(chunk.reference, DATA_OFFSET + offset, b, off, len);
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69 offset += len;
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70 return len;
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71 }
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72 }
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