1 /* DecodeRLE8.java -- 2 Copyright (C) 2005 Free Software Foundation, Inc. 3 4 This file is part of GNU Classpath. 5 6 GNU Classpath is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GNU Classpath is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GNU Classpath; see the file COPYING. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19 02110-1301 USA. 20 21 Linking this library statically or dynamically with other modules is 22 making a combined work based on this library. Thus, the terms and 23 conditions of the GNU General Public License cover the whole 24 combination. 25 26 As a special exception, the copyright holders of this library give you 27 permission to link this library with independent modules to produce an 28 executable, regardless of the license terms of these independent 29 modules, and to copy and distribute the resulting executable under 30 terms of your choice, provided that you also meet, for each linked 31 independent module, the terms and conditions of the license of that 32 module. An independent module is a module which is not derived from 33 or based on this library. If you modify this library, you may extend 34 this exception to your version of the library, but you are not 35 obligated to do so. If you do not wish to do so, delete this 36 exception statement from your version. */ 37 38 package gnu.javax.imageio.bmp; 39 40 import java.io.IOException; 41 import javax.imageio.stream.ImageInputStream; 42 import java.awt.image.BufferedImage; 43 import java.awt.image.IndexColorModel; 44 import java.awt.image.Raster; 45 import java.awt.image.WritableRaster; 46 import java.awt.image.DataBuffer; 47 import java.awt.image.DataBufferByte; 48 import java.awt.image.SinglePixelPackedSampleModel; 49 import java.awt.image.SampleModel; 50 import java.awt.Dimension; 51 52 public class DecodeRLE8 extends BMPDecoder { 53 DecodeRLE8(BMPFileHeader fh, BMPInfoHeader ih)54 public DecodeRLE8(BMPFileHeader fh, BMPInfoHeader ih){ 55 super(fh, ih); 56 } 57 58 /** 59 * RLE control codes 60 */ 61 private static final byte ESCAPE = (byte)0; 62 private static final byte EOL = (byte)0; // end of line 63 private static final byte EOB = (byte)1; // end of bitmap 64 private static final byte DELTA = (byte)2; // delta 65 decode(ImageInputStream in)66 public BufferedImage decode(ImageInputStream in) throws IOException, BMPException { 67 IndexColorModel palette = readPalette(in); 68 skipToImage(in); 69 70 Dimension d = infoHeader.getSize(); 71 int h = (int)d.getHeight(); 72 int w = (int)d.getWidth(); 73 74 byte[] data = uncompress(w, h, in); 75 SampleModel sm = new SinglePixelPackedSampleModel(DataBuffer.TYPE_BYTE, 76 w, h, 77 new int[] {0xFF}); 78 DataBuffer db = new DataBufferByte(data, w*h, 0); 79 WritableRaster raster = Raster.createWritableRaster(sm, db, null); 80 81 return new BufferedImage(palette, raster, false, null); 82 } 83 uncompress(int w, int h, ImageInputStream in)84 private byte[] uncompress(int w, int h, ImageInputStream in) 85 throws BMPException, IOException { 86 byte[] cmd = new byte[2]; 87 byte[] data = new byte[w*h]; 88 int offIn = 0; 89 int x=0,y=0; 90 91 try { 92 while((x + y*w) < w*h){ 93 if(in.read(cmd) != 2) 94 throw new IOException("Error reading compressed data."); 95 96 if(cmd[0] == ESCAPE){ 97 switch(cmd[1]){ 98 case EOB: // end of bitmap 99 return data; 100 case EOL: // end of line 101 x = 0; 102 y++; 103 break; 104 case DELTA: // delta 105 if(in.read(cmd) != 2) 106 throw new IOException("Error reading compressed data."); 107 int dx = cmd[0] & (0xFF); 108 int dy = cmd[1] & (0xFF); 109 x += dx; 110 y += dy; 111 break; 112 113 default: 114 // decode a literal run 115 int length = cmd[1] & (0xFF); 116 int copylength = length; 117 118 // absolute mode must be word-aligned 119 length += (length & 1); 120 121 byte[] run = new byte[length]; 122 if(in.read(run) != length) 123 throw new IOException("Error reading compressed data."); 124 125 System.arraycopy(run, 0, data, (x+w*(h-y-1)), 126 copylength); 127 x += copylength; 128 break; 129 } 130 } else { 131 // decode a byte run 132 int length = cmd[0] & (0xFF); 133 for(int i=0;i<length;i++) 134 data[(h-y-1)*w + x++] = cmd[1]; 135 } 136 } 137 return data; 138 } catch(ArrayIndexOutOfBoundsException e){ 139 throw new BMPException("Invalid RLE data."); 140 } 141 } 142 } 143