Packet.java

/**
 * 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 <http://www.gnu.org/licenses/>.
 */
package com.sshtools.ssh;

import java.io.IOException;

import com.sshtools.util.ByteArrayWriter;

/**
 * A utility class that provides the SSH layers with the ability to dynamically
 * write an SSH packet.
 * 
 * @author Lee David Painter
 */
public class Packet extends ByteArrayWriter {

	int markedPosition = -1;

	public Packet() throws IOException {
		this(35000);
	}

	public Packet(int size) throws IOException {
		super(size + 4);

		// Save some space for the length field
		writeInt(0);
	}

	public int setPosition(int pos) {
		int count = this.count;
		this.count = pos;
		return count;
	}

	public int position() {
		return count;
	}

	public void finish() {

		buf[0] = (byte) (count - 4 >> 24);
		buf[1] = (byte) (count - 4 >> 16);
		buf[2] = (byte) (count - 4 >> 8);
		buf[3] = (byte) (count - 4);

	}

	public void reset() {

		super.reset();
		try {
			writeInt(0);
		} catch (IOException ex) {
		}
	}
}