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/*
* ConnectBot: simple, powerful, open-source SSH client for Android
* Copyright 2007 Kenny Root, Jeffrey Sharkey
*
* 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.
*/
package com.trilead.ssh2.compression;
import com.jcraft.jzlib.JZlib;
import com.jcraft.jzlib.ZStream;
/**
* @author Kenny Root
*
*/
public class Zlib implements ICompressor {
static private final int DEFAULT_BUF_SIZE = 4096;
static private final int LEVEL = 5;
private ZStream deflate;
private byte[] deflate_tmpbuf;
private ZStream inflate;
private byte[] inflate_tmpbuf;
private byte[] inflated_buf;
public Zlib() {
deflate = new ZStream();
inflate = new ZStream();
deflate.deflateInit(LEVEL);
inflate.inflateInit();
deflate_tmpbuf = new byte[DEFAULT_BUF_SIZE];
inflate_tmpbuf = new byte[DEFAULT_BUF_SIZE];
inflated_buf = new byte[DEFAULT_BUF_SIZE];
}
public int getBufferSize() {
return DEFAULT_BUF_SIZE;
}
public int compress(byte[] buf, int start, int len, byte[] output) {
deflate.next_in = buf;
deflate.next_in_index = start;
deflate.avail_in = len - start;
if ((buf.length + 1024) > deflate_tmpbuf.length) {
deflate_tmpbuf = new byte[buf.length + 1024];
}
deflate.next_out = deflate_tmpbuf;
deflate.next_out_index = 0;
deflate.avail_out = output.length;
if (deflate.deflate(JZlib.Z_PARTIAL_FLUSH) != JZlib.Z_OK) {
System.err.println("compress: compression failure");
}
if (deflate.avail_in > 0) {
System.err.println("compress: deflated data too large");
}
int outputlen = output.length - deflate.avail_out;
System.arraycopy(deflate_tmpbuf, 0, output, 0, outputlen);
return outputlen;
}
public byte[] uncompress(byte[] buffer, int start, int[] length) {
int inflated_end = 0;
inflate.next_in = buffer;
inflate.next_in_index = start;
inflate.avail_in = length[0];
while (true) {
inflate.next_out = inflate_tmpbuf;
inflate.next_out_index = 0;
inflate.avail_out = DEFAULT_BUF_SIZE;
int status = inflate.inflate(JZlib.Z_PARTIAL_FLUSH);
switch (status) {
case JZlib.Z_OK:
if (inflated_buf.length < inflated_end + DEFAULT_BUF_SIZE
- inflate.avail_out) {
byte[] foo = new byte[inflated_end + DEFAULT_BUF_SIZE
- inflate.avail_out];
System.arraycopy(inflated_buf, 0, foo, 0, inflated_end);
inflated_buf = foo;
}
System.arraycopy(inflate_tmpbuf, 0, inflated_buf, inflated_end,
DEFAULT_BUF_SIZE - inflate.avail_out);
inflated_end += (DEFAULT_BUF_SIZE - inflate.avail_out);
length[0] = inflated_end;
break;
case JZlib.Z_BUF_ERROR:
if (inflated_end > buffer.length - start) {
byte[] foo = new byte[inflated_end + start];
System.arraycopy(buffer, 0, foo, 0, start);
System.arraycopy(inflated_buf, 0, foo, start, inflated_end);
buffer = foo;
} else {
System.arraycopy(inflated_buf, 0, buffer, start,
inflated_end);
}
length[0] = inflated_end;
return buffer;
default:
System.err.println("uncompress: inflate returnd " + status);
return null;
}
}
}
}
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