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/*
* $Id$
* ============================================================================
* The Apache Software License, Version 1.1
* ============================================================================
*
* Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modifica-
* tion, 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.
*
* 3. The end-user documentation included with the redistribution, if any, must
* include the following acknowledgment: "This product includes software
* developed by the Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself, if
* and wherever such third-party acknowledgments normally appear.
*
* 4. The names "FOP" and "Apache Software Foundation" must not be used to
* endorse or promote products derived from this software without prior
* written permission. For written permission, please contact
* apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache", nor may
* "Apache" appear in their name, without prior written permission of the
* Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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
* APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU-
* DING, 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.
* ============================================================================
*
* This software consists of voluntary contributions made by many individuals
* on behalf of the Apache Software Foundation and was originally created by
* James Tauber <jtauber@jtauber.com>. For more information on the Apache
* Software Foundation, please see <http://www.apache.org/>.
*/
package org.apache.fop.util;
import java.io.FilterOutputStream;
import java.io.OutputStream;
import java.io.IOException;
/**
* This class applies a RunLengthEncode filter to the stream.
*
* @author <a href="mailto:smwolke@geistig.com">Stephen Wolke</a>
* @version $Id$
*/
public class RunLengthEncodeOutputStream extends FilterOutputStream
implements Finalizable {
private static final int MAX_SEQUENCE_COUNT = 127;
private static final int END_OF_DATA = 128;
private static final int BYTE_MAX = 256;
private static final int NOT_IDENTIFY_SEQUENCE = 0;
private static final int START_SEQUENCE = 1;
private static final int IN_SEQUENCE = 2;
private static final int NOT_IN_SEQUENCE = 3;
private int runCount = 0;
private int isSequence = NOT_IDENTIFY_SEQUENCE;
private byte[] runBuffer = new byte[MAX_SEQUENCE_COUNT + 1];
/** @see java.io.FilterOutputStream **/
public RunLengthEncodeOutputStream(OutputStream out) {
super(out);
}
/** @see java.io.FilterOutputStream **/
public void write(byte b)
throws java.io.IOException {
runBuffer[runCount] = b;
switch (runCount) {
case 0:
runCount = 0;
isSequence = NOT_IDENTIFY_SEQUENCE;
runCount++;
break;
case 1:
if (runBuffer[runCount] != runBuffer[runCount - 1]) {
isSequence = NOT_IN_SEQUENCE;
}
runCount++;
break;
case 2:
if (runBuffer[runCount] != runBuffer[runCount - 1]) {
isSequence = NOT_IN_SEQUENCE;
} else {
if (isSequence == NOT_IN_SEQUENCE) {
isSequence = START_SEQUENCE;
} else {
isSequence = IN_SEQUENCE;
}
}
runCount++;
break;
case MAX_SEQUENCE_COUNT:
if (isSequence == IN_SEQUENCE) {
out.write(BYTE_MAX - (MAX_SEQUENCE_COUNT - 1));
out.write(runBuffer[runCount - 1]);
runBuffer[0] = runBuffer[runCount];
runCount = 1;
} else {
out.write(MAX_SEQUENCE_COUNT);
out.write(runBuffer, 0, runCount + 1);
runCount = 0;
}
isSequence = NOT_IDENTIFY_SEQUENCE;
break;
default:
switch (isSequence) {
case IN_SEQUENCE:
if (runBuffer[runCount] != runBuffer[runCount - 1]) {
out.write(BYTE_MAX - (runCount - 1));
out.write(runBuffer[runCount - 1]);
runBuffer[0] = runBuffer[runCount];
runCount = 1;
isSequence = NOT_IDENTIFY_SEQUENCE;
break;
}
runCount++;
break;
case NOT_IN_SEQUENCE:
if (runBuffer[runCount] == runBuffer[runCount - 1]) {
isSequence = START_SEQUENCE;
}
runCount++;
break;
case START_SEQUENCE:
if (runBuffer[runCount] == runBuffer[runCount - 1]) {
out.write(runCount - 3);
out.write(runBuffer, 0, runCount - 2);
runBuffer[0] = runBuffer[runCount];
runBuffer[1] = runBuffer[runCount];
runBuffer[2] = runBuffer[runCount];
runCount = 3;
isSequence = IN_SEQUENCE;
break;
} else {
isSequence = NOT_IN_SEQUENCE;
runCount++;
break;
}
}
}
}
/** @see java.io.FilterOutputStream **/
public void write(byte[] b)
throws IOException {
for (int i = 0; i < b.length; i++) {
this.write(b[i]);
}
}
/** @see java.io.FilterOutputStream **/
public void write(byte[] b, int off, int len)
throws IOException {
for (int i = 0; i < len; i++) {
this.write(b[off + i]);
}
}
/** @see Finalizable **/
public void finalizeStream()
throws IOException {
switch (isSequence) {
case IN_SEQUENCE:
out.write(BYTE_MAX - (runCount - 1));
out.write(runBuffer[runCount - 1]);
break;
default:
out.write(runCount - 1);
out.write(runBuffer, 0, runCount);
}
out.write(END_OF_DATA);
flush();
if (out instanceof Finalizable) {
((Finalizable) out).finalizeStream();
}
}
/** @see java.io.FilterOutputStream **/
public void close()
throws IOException {
finalizeStream();
super.close();
}
}
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