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//
// ========================================================================
// Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.websocket.common.extensions.compress;
import java.nio.ByteBuffer;
import java.util.zip.DataFormatException;
import java.util.zip.Deflater;
import java.util.zip.Inflater;
import org.eclipse.jetty.util.BufferUtil;
import org.eclipse.jetty.util.TypeUtil;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
import org.eclipse.jetty.websocket.api.BadPayloadException;
/**
* Deflate Compression Method
*/
public class DeflateCompressionMethod implements CompressionMethod
{
private static class DeflaterProcess implements CompressionMethod.Process
{
private static final boolean BFINAL_HACK = Boolean.parseBoolean(System.getProperty("jetty.websocket.bfinal.hack","true"));
private final Deflater deflater;
private int bufferSize = DEFAULT_BUFFER_SIZE;
public DeflaterProcess(boolean nowrap)
{
deflater = new Deflater(Deflater.BEST_COMPRESSION,nowrap);
deflater.setStrategy(Deflater.DEFAULT_STRATEGY);
}
@Override
public void begin()
{
deflater.reset();
}
@Override
public void end()
{
deflater.reset();
}
@Override
public void input(ByteBuffer input)
{
if (LOG.isDebugEnabled())
{
LOG.debug("input: {}",BufferUtil.toDetailString(input));
}
// Set the data that is uncompressed to the deflater
byte raw[] = BufferUtil.toArray(input);
deflater.setInput(raw,0,raw.length);
deflater.finish();
}
@Override
public boolean isDone()
{
return deflater.finished();
}
@Override
public ByteBuffer process()
{
// prepare the output buffer
ByteBuffer buf = ByteBuffer.allocate(bufferSize);
BufferUtil.clearToFill(buf);
while (!deflater.finished())
{
byte out[] = new byte[bufferSize];
int len = deflater.deflate(out,0,out.length,Deflater.SYNC_FLUSH);
if (LOG.isDebugEnabled())
{
LOG.debug("Deflater: finished={}, needsInput={}, len={}",deflater.finished(),deflater.needsInput(),len);
}
buf.put(out,0,len);
}
BufferUtil.flipToFlush(buf,0);
if (BFINAL_HACK)
{
/*
* Per the spec, it says that BFINAL 1 or 0 are allowed.
*
* However, Java always uses BFINAL 1, whereas the browsers Chromium and Safari fail to decompress when it encounters BFINAL 1.
*
* This hack will always set BFINAL 0
*/
byte b0 = buf.get(0);
if ((b0 & 1) != 0) // if BFINAL 1
{
buf.put(0,(b0 ^= 1)); // flip bit to BFINAL 0
}
}
return buf;
}
public void setBufferSize(int bufferSize)
{
this.bufferSize = bufferSize;
}
}
private static class InflaterProcess implements CompressionMethod.Process
{
/** Tail Bytes per Spec */
private static final byte[] TAIL = new byte[]
{ 0x00, 0x00, (byte)0xFF, (byte)0xFF };
private final Inflater inflater;
private int bufferSize = DEFAULT_BUFFER_SIZE;
public InflaterProcess(boolean nowrap) {
inflater = new Inflater(nowrap);
}
@Override
public void begin()
{
inflater.reset();
}
@Override
public void end()
{
inflater.reset();
}
@Override
public void input(ByteBuffer input)
{
if (LOG.isDebugEnabled())
{
LOG.debug("inflate: {}",BufferUtil.toDetailString(input));
LOG.debug("Input Data: {}",TypeUtil.toHexString(BufferUtil.toArray(input)));
}
// Set the data that is compressed (+ TAIL) to the inflater
int len = input.remaining() + 4;
byte raw[] = new byte[len];
int inlen = input.remaining();
input.slice().get(raw,0,inlen);
System.arraycopy(TAIL,0,raw,inlen,TAIL.length);
inflater.setInput(raw,0,raw.length);
}
@Override
public boolean isDone()
{
return (inflater.getRemaining() <= 0) || inflater.finished();
}
@Override
public ByteBuffer process()
{
// Establish place for inflated data
byte buf[] = new byte[bufferSize];
try
{
int inflated = inflater.inflate(buf);
if (inflated == 0)
{
return null;
}
ByteBuffer ret = BufferUtil.toBuffer(buf,0,inflated);
if (LOG.isDebugEnabled())
{
LOG.debug("uncompressed={}",BufferUtil.toDetailString(ret));
}
return ret;
}
catch (DataFormatException e)
{
LOG.warn(e);
throw new BadPayloadException(e);
}
}
public void setBufferSize(int bufferSize)
{
this.bufferSize = bufferSize;
}
}
private static final int DEFAULT_BUFFER_SIZE = 61*1024;
private static final Logger LOG = Log.getLogger(DeflateCompressionMethod.class);
private int bufferSize = 64 * 1024;
private final DeflaterProcess compress;
private final InflaterProcess decompress;
public DeflateCompressionMethod()
{
/*
* Specs specify that head/tail of deflate are not to be present.
*
* So lets not use the wrapped format of bytes.
*
* Setting nowrap to true prevents the Deflater from writing the head/tail bytes and the Inflater from expecting the head/tail bytes.
*/
boolean nowrap = true;
this.compress = new DeflaterProcess(nowrap);
this.decompress = new InflaterProcess(nowrap);
}
@Override
public Process compress()
{
return compress;
}
@Override
public Process decompress()
{
return decompress;
}
public int getBufferSize()
{
return bufferSize;
}
public void setBufferSize(int size)
{
if (size < 64)
{
throw new IllegalArgumentException("Buffer Size [" + size + "] cannot be less than 64 bytes");
}
this.bufferSize = size;
this.compress.setBufferSize(bufferSize);
this.decompress.setBufferSize(bufferSize);
}
}
