/*
* Copyright 2003-2008 by Paulo Soares.
*
* This code was originally released in 2001 by SUN (see class
* com.sun.media.imageio.plugins.tiff.TIFFDirectory.java)
* using the BSD license in a specific wording. In a mail dating from
* January 23, 2008, Brian Burkhalter (@sun.com) gave us permission
* to use the code under the following version of the BSD license:
*
* 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: 4540 $
* $Date: 2010-07-13 14:57:54 +0200 (di, 13 jul 2010) $
* $State: Exp $
*/
package com.itextpdf.text.pdf.codec;
import java.io.IOException;
import java.io.OutputStream;
/**
* Came from GIFEncoder initially.
* Modified - to allow for output compressed data without the block counts
* which breakup the compressed data stream for GIF.
* @since 5.0.2
*/
public class BitFile
{
OutputStream 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(OutputStream 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);
}
}
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