/*
* Copyright 2010, 2011 sshj contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file may incorporate work covered by the following copyright and
* permission notice:
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package net.schmizz.sshj.transport.compression;
import com.jcraft.jzlib.JZlib;
import com.jcraft.jzlib.ZStream;
import net.schmizz.sshj.common.Buffer;
import net.schmizz.sshj.common.DisconnectReason;
import net.schmizz.sshj.common.SSHRuntimeException;
import net.schmizz.sshj.transport.TransportException;
/** ZLib based Compression. */
public class ZlibCompression
implements Compression {
/** Named factory for the ZLib Compression. */
public static class Factory
implements net.schmizz.sshj.common.Factory.Named<Compression> {
@Override
public Compression create() {
return new ZlibCompression();
}
@Override
public String getName() {
return "zlib";
}
}
private static final int BUF_SIZE = 4096;
private final byte[] tempBuf = new byte[BUF_SIZE];
private ZStream stream;
@Override
public void init(Mode mode) {
stream = new ZStream();
switch (mode) {
case DEFLATE:
stream.deflateInit(JZlib.Z_DEFAULT_COMPRESSION);
break;
case INFLATE:
stream.inflateInit();
break;
default:
assert false;
}
}
@Override
public boolean isDelayed() {
return false;
}
@Override
public void compress(Buffer buffer) {
stream.next_in = buffer.array();
stream.next_in_index = buffer.rpos();
stream.avail_in = buffer.available();
buffer.wpos(buffer.rpos());
do {
stream.next_out = tempBuf;
stream.next_out_index = 0;
stream.avail_out = BUF_SIZE;
final int status = stream.deflate(JZlib.Z_PARTIAL_FLUSH);
if (status == JZlib.Z_OK) {
buffer.putRawBytes(tempBuf, 0, BUF_SIZE - stream.avail_out);
} else {
throw new SSHRuntimeException("compress: deflate returned " + status);
}
} while (stream.avail_out == 0);
}
@Override
public void uncompress(Buffer from, Buffer to)
throws TransportException {
stream.next_in = from.array();
stream.next_in_index = from.rpos();
stream.avail_in = from.available();
while (true) {
stream.next_out = tempBuf;
stream.next_out_index = 0;
stream.avail_out = BUF_SIZE;
final int status = stream.inflate(JZlib.Z_PARTIAL_FLUSH);
switch (status) {
case JZlib.Z_OK:
to.putRawBytes(tempBuf, 0, BUF_SIZE - stream.avail_out);
break;
case JZlib.Z_BUF_ERROR:
return;
default:
throw new TransportException(DisconnectReason.COMPRESSION_ERROR, "uncompress: inflate returned "
+ status);
}
}
}
}