001/*
002 * $RCSfile: TIFFRLECompressor.java,v $
003 *
004 * 
005 * Copyright (c) 2005 Sun Microsystems, Inc. All  Rights Reserved.
006 * 
007 * Redistribution and use in source and binary forms, with or without
008 * modification, are permitted provided that the following conditions
009 * are met: 
010 * 
011 * - Redistribution of source code must retain the above copyright 
012 *   notice, this  list of conditions and the following disclaimer.
013 * 
014 * - Redistribution in binary form must reproduce the above copyright
015 *   notice, this list of conditions and the following disclaimer in 
016 *   the documentation and/or other materials provided with the
017 *   distribution.
018 * 
019 * Neither the name of Sun Microsystems, Inc. or the names of 
020 * contributors may be used to endorse or promote products derived 
021 * from this software without specific prior written permission.
022 * 
023 * This software is provided "AS IS," without a warranty of any 
024 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND 
025 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, 
026 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
027 * EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL 
028 * NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF 
029 * USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
030 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR 
031 * ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
032 * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
033 * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
034 * INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
035 * POSSIBILITY OF SUCH DAMAGES. 
036 * 
037 * You acknowledge that this software is not designed or intended for 
038 * use in the design, construction, operation or maintenance of any 
039 * nuclear facility. 
040 *
041 * $Revision: 1.1 $
042 * $Date: 2005/02/11 05:01:49 $
043 * $State: Exp $
044 */
045package com.github.jaiimageio.impl.plugins.tiff;
046
047import java.io.IOException;
048
049import javax.imageio.IIOException;
050
051import com.github.jaiimageio.plugins.tiff.BaselineTIFFTagSet;
052
053/**
054 *
055 */
056public class TIFFRLECompressor extends TIFFFaxCompressor {
057
058    public TIFFRLECompressor() {
059        super("CCITT RLE", BaselineTIFFTagSet.COMPRESSION_CCITT_RLE, true);
060    }
061
062    /**
063     * Encode a row of data using Modified Huffman Compression also known as
064     * CCITT RLE (Run Lenth Encoding).
065     *
066     * @param data        The row of data to compress.
067     * @param rowOffset   Starting index in <code>data</code>.
068     * @param colOffset   Bit offset within first <code>data[rowOffset]</code>.
069     * @param rowLength   Number of bits in the row.
070     * @param compData    The compressed data.
071     *
072     * @return The number of bytes saved in the compressed data array.
073     */
074    public int encodeRLE(byte[] data,
075                         int rowOffset,
076                         int colOffset,
077                         int rowLength,
078                         byte[] compData) {
079        //
080        // Initialize bit buffer machinery.
081        //
082        initBitBuf();
083
084        //
085        // Run-length encode line.
086        //
087        int outIndex =
088            encode1D(data, rowOffset, colOffset, rowLength, compData, 0);
089
090        //
091        // Flush pending bits
092        //
093        while (ndex > 0) {
094            compData[outIndex++] = (byte)(bits >>> 24);
095            bits <<= 8;
096            ndex -= 8;
097        }
098
099        //
100        // Flip the bytes if inverse fill was requested.
101        //
102        if (inverseFill) {
103            byte[] flipTable = TIFFFaxDecompressor.flipTable;
104            for(int i = 0; i < outIndex; i++) {
105                compData[i] = flipTable[compData[i] & 0xff];
106            }
107        }
108
109        return outIndex;
110    }
111
112    public int encode(byte[] b, int off,
113                      int width, int height,
114                      int[] bitsPerSample,
115                      int scanlineStride) throws IOException {
116        if (bitsPerSample.length != 1 || bitsPerSample[0] != 1) {
117            throw new IIOException(
118                            "Bits per sample must be 1 for RLE compression!"); 
119        }
120
121        // In the worst case, 2 bits of input will result in 9 bits of output,
122        // plus 2 extra bits if the row starts with black.
123        int maxBits = 9*((width + 1)/2) + 2;
124        byte[] compData = new byte[(maxBits + 7)/8];
125
126        int bytes = 0;
127        int rowOffset = off;
128
129        for (int i = 0; i < height; i++) {
130            int rowBytes = encodeRLE(b, rowOffset, 0, width, compData);
131            stream.write(compData, 0, rowBytes);
132            
133            rowOffset += scanlineStride;
134            bytes += rowBytes;
135        }
136
137        return bytes;
138    }
139}