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/*
ConnectBot: simple, powerful, open-source SSH client for Android
Copyright (C) 2007-2008 Kenny Root, Jeffrey Sharkey
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
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 BUF_SIZE = 4096;
static private final int LEVEL = 5;
private ZStream deflate;
private byte[] deflate_tmpbuf = new byte[BUF_SIZE];
private ZStream inflate;
private byte[] inflate_tmpbuf = new byte[BUF_SIZE];
private byte[] inflated_buf;
public Zlib() {
deflate = new ZStream();
inflate = new ZStream();
deflate.deflateInit(LEVEL);
inflate.inflateInit();
inflated_buf = new byte[BUF_SIZE];
}
public int getBufferSize() {
return 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;
int status;
int outputlen = start;
do {
deflate.next_out = deflate_tmpbuf;
deflate.next_out_index = 0;
deflate.avail_out = BUF_SIZE;
status = deflate.deflate(JZlib.Z_PARTIAL_FLUSH);
switch (status) {
case JZlib.Z_OK:
System.arraycopy(deflate_tmpbuf, 0, output, outputlen, BUF_SIZE
- deflate.avail_out);
outputlen += (BUF_SIZE - deflate.avail_out);
break;
default:
System.err.println("compress: deflate returnd " + status);
}
} while (deflate.avail_out == 0);
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 = BUF_SIZE;
int status = inflate.inflate(JZlib.Z_PARTIAL_FLUSH);
switch (status) {
case JZlib.Z_OK:
if (inflated_buf.length < inflated_end + BUF_SIZE
- inflate.avail_out) {
byte[] foo = new byte[inflated_end + 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,
BUF_SIZE - inflate.avail_out);
inflated_end += (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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