| /* DecodeRLE4.java -- |
| Copyright (C) 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package gnu.javax.imageio.bmp; |
| |
| import java.io.IOException; |
| import javax.imageio.stream.ImageInputStream; |
| import java.awt.image.BufferedImage; |
| import java.awt.image.IndexColorModel; |
| import java.awt.image.Raster; |
| import java.awt.image.WritableRaster; |
| import java.awt.image.DataBuffer; |
| import java.awt.image.DataBufferByte; |
| import java.awt.image.MultiPixelPackedSampleModel; |
| import java.awt.image.SampleModel; |
| import java.awt.Dimension; |
| |
| public class DecodeRLE4 extends BMPDecoder { |
| |
| public DecodeRLE4(BMPFileHeader fh, BMPInfoHeader ih){ |
| super(fh, ih); |
| } |
| |
| /** |
| * RLE control codes |
| */ |
| private static final byte ESCAPE = (byte)0; |
| private static final byte EOL = (byte)0; // end of line |
| private static final byte EOB = (byte)1; // end of bitmap |
| private static final byte DELTA = (byte)2; // delta |
| |
| public BufferedImage decode(ImageInputStream in) throws IOException, BMPException { |
| IndexColorModel palette = readPalette(in); |
| skipToImage(in); |
| |
| Dimension d = infoHeader.getSize(); |
| int h = (int)d.getHeight(); |
| int w = (int)d.getWidth(); |
| |
| byte[] data = uncompress(w, h, in); |
| SampleModel sm = new MultiPixelPackedSampleModel(DataBuffer.TYPE_BYTE, |
| w, h, 4); |
| |
| DataBuffer db = new DataBufferByte(data, w*h, 0); |
| WritableRaster raster = Raster.createWritableRaster(sm, db, null); |
| |
| return new BufferedImage(palette, raster, false, null); |
| } |
| |
| private byte[] uncompress(int w, int h, ImageInputStream in) |
| throws BMPException, IOException { |
| byte[] cmd = new byte[2]; |
| byte[] data = new byte[w*h>>1]; |
| int offIn = 0; |
| int x=0,y=0; |
| |
| // width in bytes |
| w += (w&1); |
| w = w >> 1; |
| |
| try { |
| while(((x>>1) + y*w) < w*h){ |
| if(in.read(cmd) != 2) |
| throw new IOException("Error reading compressed data."); |
| |
| if(cmd[0] == ESCAPE){ |
| switch(cmd[1]){ |
| case EOB: // end of bitmap |
| return data; |
| case EOL: // end of line |
| x = 0; |
| y++; |
| break; |
| case DELTA: // delta |
| if(in.read(cmd) != 2) |
| throw new IOException("Error reading compressed data."); |
| int dx = cmd[0] & (0xFF); |
| int dy = cmd[1] & (0xFF); |
| x += dx; |
| y += dy; |
| break; |
| |
| default: |
| // decode a literal run |
| int length = cmd[1] & (0xFF); |
| |
| // size of run, which is word aligned. |
| int bytesize = length; |
| bytesize += (bytesize & 1); |
| bytesize >>= 1; |
| bytesize += (bytesize & 1); |
| |
| byte[] run = new byte[bytesize]; |
| if(in.read(run) != bytesize) |
| throw new IOException("Error reading compressed data."); |
| |
| if((x&1) == 0){ |
| length += (length&1); |
| length >>= 1; |
| System.arraycopy(run, 0, data, ((x>>1) + w*(h-y-1)), |
| length); |
| } else { |
| for(int i=0;i<length;i++){ |
| if((i&1) == 0) // copy high to low |
| data[((x+i)>>1) + w*(h-y-1)] |
| |= ((run[i>>1]&0xF0) >> 4); |
| else // copy low to high |
| data[((x+i)>>1) + w*(h-y-1)] |
| |= ((run[i>>1]&0x0F) << 4); |
| } |
| } |
| x += cmd[1] & (0xFF); |
| break; |
| } |
| } else { |
| // decode a byte run |
| int length = cmd[0] & (0xFF); |
| if((x&1) == 0){ |
| length += (length&1); |
| length >>= 1; |
| for(int i=0;i<length;i++) |
| data[(h-y-1)*w + i + (x >> 1)] = cmd[1]; |
| } else { |
| for(int i=0;i<length;i++){ |
| if((i&1) == 0) // copy high to low |
| data[((x+i)>>1) + w*(h-y-1)] |
| |= ((cmd[1]&0xF0) >> 4); |
| else // copy low to high |
| data[((x+i)>>1) + w*(h-y-1)] |
| |= ((cmd[1]&0x0F) << 4); |
| } |
| } |
| x += cmd[0] & (0xFF); |
| } |
| } |
| return data; |
| } catch(ArrayIndexOutOfBoundsException e){ |
| throw new BMPException("Invalid RLE data."); |
| } |
| } |
| } |
| |