org.eclipse.jetty.servlets.gzip.GzipOutputStream Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995-2018 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.servlets.gzip;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.CRC32;
import java.util.zip.Deflater;
/**
* Reimplementation of {@link java.util.zip.GZIPOutputStream} that supports reusing a {@link Deflater} instance.
*/
public class GzipOutputStream extends DeflatedOutputStream
{
private final static byte[] GZIP_HEADER = new byte[]
{ (byte)0x1f, (byte)0x8b, Deflater.DEFLATED, 0, 0, 0, 0, 0, 0, 0 };
private final CRC32 _crc = new CRC32();
public GzipOutputStream(OutputStream out, Deflater deflater, byte[] buffer) throws IOException
{
super(out,deflater,buffer);
out.write(GZIP_HEADER);
}
@Override
public synchronized void write(byte[] buf, int off, int len) throws IOException
{
super.write(buf,off,len);
_crc.update(buf,off,len);
}
@Override
public synchronized void finish() throws IOException
{
if (!_def.finished())
{
super.finish();
byte[] trailer = new byte[8];
writeInt((int)_crc.getValue(),trailer,0);
writeInt(_def.getTotalIn(),trailer,4);
out.write(trailer);
}
}
private void writeInt(int i, byte[] buf, int offset)
{
int o = offset;
buf[o++] = (byte)(i & 0xFF);
buf[o++] = (byte)((i >>> 8) & 0xFF);
buf[o++] = (byte)((i >>> 16) & 0xFF);
buf[o++] = (byte)((i >>> 24) & 0xFF);
}
}