Mercurial > 510Connectbot
diff src/com/trilead/ssh2/compression/Zlib.java @ 0:0ce5cc452d02
initial version
author | Carl Byington <carl@five-ten-sg.com> |
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date | Thu, 22 May 2014 10:41:19 -0700 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/com/trilead/ssh2/compression/Zlib.java Thu May 22 10:41:19 2014 -0700 @@ -0,0 +1,131 @@ +/* + * 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 boolean canCompressPreauth() { + return true; + } + + 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; + } + } + } +}