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/*
* TIFFDecoderDeflated
*
* Copyright (c) 2002, 2003, 2004, 2005, 2006 Marco Schmidt.
* All rights reserved.
*/
package net.sourceforge.jiu.codecs.tiff;
import java.io.DataInput;
import java.io.IOException;
import java.util.zip.DataFormatException;
import java.util.zip.Inflater;
import net.sourceforge.jiu.codecs.tiff.TIFFConstants;
import net.sourceforge.jiu.codecs.tiff.TIFFDecoder;
import net.sourceforge.jiu.codecs.tiff.TIFFImageFileDirectory;
import net.sourceforge.jiu.codecs.InvalidFileStructureException;
import net.sourceforge.jiu.ops.MissingParameterException;
/**
* A TIFF decoder for files compressed with the <em>Deflated</em> method.
* This compression algorithm has the values <code>31946</code>
* ({@link TIFFConstants#COMPRESSION_DEFLATED_INOFFICIAL}) and <code>8</code>
* ({@link TIFFConstants#COMPRESSION_DEFLATED_OFFICIAL})
* in the compression tag of an image file directory.
* All types of image data can be compressed with this method.
* <p>
* This decoder makes use of the package java.util.zip which comes with an Inflater
* class that does most of the work.
* All the decoder has to do is feed the Inflater object with compressed data from
* the input file and give decompressed data received from the Inflater to the
* putBytes method.
* @author Marco Schmidt
* @since 0.9.0
*/
public class TIFFDecoderDeflated extends TIFFDecoder
{
private DataInput in;
private int compressedSize;
public void decode() throws
InvalidFileStructureException,
IOException
{
Inflater inflater = new Inflater();
byte[] ioBuffer = new byte[20000];
byte[] data = new byte[getBytesPerRow()];
// determine how many bytes have to be read from inflater
int numRows = getY2();
TIFFImageFileDirectory ifd = getImageFileDirectory();
if (numRows > ifd.getHeight() - 1)
{
numRows = ifd.getHeight() - 1;
}
numRows -= getY1();
int remainingBytes = numRows * data.length;
// now read and decompress as long as there is data left to decompress
while (compressedSize > 0 || remainingBytes > 0)
{
if (inflater.needsInput())
{
// read compressed data from input
int numBytes;
if (compressedSize > ioBuffer.length)
{
numBytes = ioBuffer.length;
}
else
{
numBytes = compressedSize;
}
in.readFully(ioBuffer, 0, numBytes);
// give data to inflater
inflater.setInput(ioBuffer, 0, numBytes);
compressedSize -= numBytes;
}
else
{
// determine how many bytes to decompress in this loop iteration
int numBytes;
if (remainingBytes > data.length)
{
numBytes = data.length;
}
else
{
numBytes = remainingBytes;
}
int numInflated;
// do the decompression
try
{
numInflated = inflater.inflate(data, 0, numBytes);
}
catch (DataFormatException dfe)
{
throw new InvalidFileStructureException("Error in compressed input data: " + dfe.toString());
}
// store decompressed data and update number of bytes left to decompress
if (numInflated > 0)
{
putBytes(data, 0, numInflated);
remainingBytes -= numInflated;
}
}
}
}
public Integer[] getCompressionTypes()
{
return new Integer[]
{
new Integer(TIFFConstants.COMPRESSION_DEFLATED_INOFFICIAL),
new Integer(TIFFConstants.COMPRESSION_DEFLATED_OFFICIAL)
};
}
public void initialize() throws
IOException,
MissingParameterException
{
super.initialize();
in = getInput();
compressedSize = getImageFileDirectory().getByteCount(getTileIndex());
}
}
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