com.sshtools.zlib.ZLibCompression Maven / Gradle / Ivy
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/**
* Copyright 2003-2016 SSHTOOLS Limited. All Rights Reserved.
*
* For product documentation visit https://www.sshtools.com/
*
* This file is part of J2SSH Maverick.
*
* J2SSH Maverick is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* J2SSH Maverick is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with J2SSH Maverick. If not, see .
*/
package com.sshtools.zlib;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import com.jcraft.jzlib.JZlib;
import com.jcraft.jzlib.ZStream;
import com.sshtools.ssh.compression.SshCompression;
@SuppressWarnings("deprecation")
public class ZLibCompression implements SshCompression {
public ZLibCompression() {
stream = new ZStream();
}
public String getAlgorithm() {
return "zlib";
}
static private final int BUF_SIZE = 65535;
ByteArrayOutputStream compressOut = new ByteArrayOutputStream(BUF_SIZE);
ByteArrayOutputStream uncompressOut = new ByteArrayOutputStream(BUF_SIZE);
// private int type;
private ZStream stream;
private byte[] inflated_buf = new byte[BUF_SIZE];
private byte[] tmpbuf = new byte[BUF_SIZE];
public void init(int type, int level) {
if (type == SshCompression.DEFLATER) {
stream.deflateInit(level);
} else if (type == SshCompression.INFLATER) {
stream.inflateInit();
}
}
public byte[] compress(byte[] buf, int start, int len) throws IOException {
compressOut.reset();
stream.next_in = buf;
stream.next_in_index = start;
stream.avail_in = len - start;
int status;
do {
stream.next_out = tmpbuf;
stream.next_out_index = 0;
stream.avail_out = BUF_SIZE;
status = stream.deflate(JZlib.Z_PARTIAL_FLUSH);
switch (status) {
case JZlib.Z_OK:
compressOut.write(tmpbuf, 0, BUF_SIZE - stream.avail_out);
break;
default:
throw new IOException("compress: deflate returnd " + status);
}
} while (stream.avail_out == 0);
return compressOut.toByteArray();
}
public byte[] uncompress(byte[] buffer, int start, int length)
throws IOException {
// int inflated_end = 0;
uncompressOut.reset();
stream.next_in = buffer;
stream.next_in_index = start;
stream.avail_in = length;
while (true) {
stream.next_out = inflated_buf;
stream.next_out_index = 0;
stream.avail_out = BUF_SIZE;
int status = stream.inflate(JZlib.Z_PARTIAL_FLUSH);
switch (status) {
case JZlib.Z_OK:
uncompressOut.write(inflated_buf, 0, BUF_SIZE
- stream.avail_out);
break;
case JZlib.Z_BUF_ERROR:
return uncompressOut.toByteArray();
default:
throw new IOException("uncompress: inflate returnd " + status);
}
}
}
}