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Image encoding and decoding routines.
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/*
* #%L
* Image encoding and decoding routines.
* %%
* Copyright (C) 2005 - 2017 Open Microscopy Environment:
* - Board of Regents of the University of Wisconsin-Madison
* - Glencoe Software, Inc.
* - University of Dundee
* %%
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* #L%
*/
package ome.codecs;
import java.io.IOException;
import java.util.HashMap;
import loci.common.ByteArrayHandle;
import loci.common.RandomAccessInputStream;
import ome.codecs.CodecException;
import ome.codecs.UnsupportedCompressionException;
/**
* This class implements Huffman decoding.
*
* @author Melissa Linkert melissa at glencoesoftware.com
*/
public class HuffmanCodec extends BaseCodec {
// -- Constants --
private static final int LEAVES_OFFSET = 16;
// -- Fields --
private int leafCounter;
private HashMap cachedDecoders =
new HashMap();
// -- Codec API methods --
/* @see Codec#compress(byte[], CodecOptions) */
@Override
public byte[] compress(byte[] data, CodecOptions options)
throws CodecException
{
throw new UnsupportedCompressionException(
"Huffman encoding not currently supported");
}
/**
* The CodecOptions parameter must be an instance of
* {@link HuffmanCodecOptions}, and should have the following fields set:
* {@link HuffmanCodecOptions#table table}
* {@link CodecOptions#bitsPerSample bitsPerSample}
* {@link CodecOptions#maxBytes maxBytes}
*
* @see Codec#decompress(RandomAccessInputStream, CodecOptions)
*/
@Override
public byte[] decompress(RandomAccessInputStream in, CodecOptions options)
throws CodecException, IOException
{
if (in == null)
throw new IllegalArgumentException("No data to decompress.");
if (options == null || !(options instanceof HuffmanCodecOptions)) {
throw new CodecException("Options must be an instance of " +
"ome.codecs.HuffmanCodecOptions.");
}
HuffmanCodecOptions huffman = (HuffmanCodecOptions) options;
int nSamples = (huffman.maxBytes * 8) / huffman.bitsPerSample;
int bytesPerSample = huffman.bitsPerSample / 8;
if ((huffman.bitsPerSample % 8) != 0) bytesPerSample++;
BitWriter out = new BitWriter();
for (int i=0; i