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 com.github.jaiimageio.plugins.tiff.BaselineTIFFTagSet;
048import com.github.jaiimageio.plugins.tiff.TIFFCompressor;
049
050import java.io.IOException;
051
052import javax.imageio.IIOException;
053
054/**
055 *
056 */
057public class TIFFRLECompressor extends TIFFFaxCompressor {
058
059    public TIFFRLECompressor() {
060        super("CCITT RLE", BaselineTIFFTagSet.COMPRESSION_CCITT_RLE, true);
061    }
062
063    /**
064     * Encode a row of data using Modified Huffman Compression also known as
065     * CCITT RLE (Run Lenth Encoding).
066     *
067     * @param data        The row of data to compress.
068     * @param rowOffset   Starting index in <code>data</code>.
069     * @param colOffset   Bit offset within first <code>data[rowOffset]</code>.
070     * @param rowLength   Number of bits in the row.
071     * @param compData    The compressed data.
072     *
073     * @return The number of bytes saved in the compressed data array.
074     */
075    public int encodeRLE(byte[] data,
076                         int rowOffset,
077                         int colOffset,
078                         int rowLength,
079                         byte[] compData) {
080        //
081        // Initialize bit buffer machinery.
082        //
083        initBitBuf();
084
085        //
086        // Run-length encode line.
087        //
088        int outIndex =
089            encode1D(data, rowOffset, colOffset, rowLength, compData, 0);
090
091        //
092        // Flush pending bits
093        //
094        while (ndex > 0) {
095            compData[outIndex++] = (byte)(bits >>> 24);
096            bits <<= 8;
097            ndex -= 8;
098        }
099
100        //
101        // Flip the bytes if inverse fill was requested.
102        //
103        if (inverseFill) {
104            byte[] flipTable = TIFFFaxDecompressor.flipTable;
105            for(int i = 0; i < outIndex; i++) {
106                compData[i] = flipTable[compData[i] & 0xff];
107            }
108        }
109
110        return outIndex;
111    }
112
113    public int encode(byte[] b, int off,
114                      int width, int height,
115                      int[] bitsPerSample,
116                      int scanlineStride) throws IOException {
117        if (bitsPerSample.length != 1 || bitsPerSample[0] != 1) {
118            throw new IIOException(
119                            "Bits per sample must be 1 for RLE compression!"); 
120        }
121
122        // In the worst case, 2 bits of input will result in 9 bits of output,
123        // plus 2 extra bits if the row starts with black.
124        int maxBits = 9*((width + 1)/2) + 2;
125        byte[] compData = new byte[(maxBits + 7)/8];
126
127        int bytes = 0;
128        int rowOffset = off;
129
130        for (int i = 0; i < height; i++) {
131            int rowBytes = encodeRLE(b, rowOffset, 0, width, compData);
132            stream.write(compData, 0, rowBytes);
133            
134            rowOffset += scanlineStride;
135            bytes += rowBytes;
136        }
137
138        return bytes;
139    }
140}