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Java Advanced Imaging Image I/O Tools API core, but without the classes
involved with javax.media.jai dependencies, JPEG2000 or
codecLibJIIO, meaning that this library can be distributed under the
modified BSD license and should be GPL compatible.
The newest version!
/*
* $RCSfile: BitFile.java,v $
*
*
* Copyright (c) 2005 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistribution of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistribution 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.
*
* Neither the name of Sun Microsystems, Inc. or the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any
* kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
* WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
* EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL
* NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF
* USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
* DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR
* ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
* CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
* REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
* INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that this software is not designed or intended for
* use in the design, construction, operation or maintenance of any
* nuclear facility.
*
* $Revision: 1.1 $
* $Date: 2005/02/11 05:01:21 $
* $State: Exp $
*/
package com.github.jaiimageio.impl.common;
import java.io.IOException;
import javax.imageio.stream.ImageOutputStream;
/**
* Came from GIFEncoder initially.
* Modified - to allow for output compressed data without the block counts
* which breakup the compressed data stream for GIF.
**/
public class BitFile
{
ImageOutputStream output_;
byte buffer_[];
int index_;
int bitsLeft_; // bits left at current index that are avail.
/** note this also indicates gif format BITFile. **/
boolean blocks_ = false;
/**
* @param output destination for output data
* @param blocks GIF LZW requires block counts for output data
**/
public BitFile(ImageOutputStream output, boolean blocks)
{
output_ = output;
blocks_ = blocks;
buffer_ = new byte[256];
index_ = 0;
bitsLeft_ = 8;
}
public void flush() throws IOException
{
int numBytes = index_ + (bitsLeft_ == 8 ? 0 : 1);
if (numBytes > 0)
{
if (blocks_)
output_.write(numBytes);
output_.write(buffer_, 0, numBytes);
buffer_[0] = 0;
index_ = 0;
bitsLeft_ = 8;
}
}
public void writeBits(int bits, int numbits) throws IOException
{
int bitsWritten = 0;
int numBytes = 255; // gif block count
do
{
// This handles the GIF block count stuff
if ((index_ == 254 && bitsLeft_ == 0) || index_ > 254)
{
if (blocks_)
output_.write(numBytes);
output_.write(buffer_, 0, numBytes);
buffer_[0] = 0;
index_ = 0;
bitsLeft_ = 8;
}
if (numbits <= bitsLeft_) // bits contents fit in current index byte
{
if (blocks_) // GIF
{
buffer_[index_] |= (bits & ((1 << numbits) - 1)) << (8 - bitsLeft_);
bitsWritten += numbits;
bitsLeft_ -= numbits;
numbits = 0;
}
else
{
buffer_[index_] |= (bits & ((1 << numbits) - 1)) << (bitsLeft_ - numbits);
bitsWritten += numbits;
bitsLeft_ -= numbits;
numbits = 0;
}
}
else // bits overflow from current byte to next.
{
if (blocks_) // GIF
{
// if bits > space left in current byte then the lowest order bits
// of code are taken and put in current byte and rest put in next.
buffer_[index_] |= (bits & ((1 << bitsLeft_) - 1)) << (8 - bitsLeft_);
bitsWritten += bitsLeft_;
bits >>= bitsLeft_;
numbits -= bitsLeft_;
buffer_[++index_] = 0;
bitsLeft_ = 8;
}
else
{
// if bits > space left in current byte then the highest order bits
// of code are taken and put in current byte and rest put in next.
// at highest order bit location !!
int topbits = (bits >>> (numbits - bitsLeft_)) & ((1 << bitsLeft_) - 1);
buffer_[index_] |= topbits;
numbits -= bitsLeft_; // ok this many bits gone off the top
bitsWritten += bitsLeft_;
buffer_[++index_] = 0; // next index
bitsLeft_ = 8;
}
}
} while (numbits != 0);
}
}