UnknownAttribute.java

/*
 * This file is part of JSTUN. 
 * 
 * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
 * reserved.
 * 
 * This software is licensed under either the GNU Public License (GPL),
 * or the Apache 2.0 license. Copies of both license agreements are
 * included in this distribution.
 */

package de.javawi.jstun.attribute;

import java.util.Iterator;
import java.util.Vector;

import de.javawi.jstun.util.Utility;
import de.javawi.jstun.util.UtilityException;

public class UnknownAttribute extends MessageAttribute {
	/*
	 * 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
	 * Attribute 1 Type | Attribute 2 Type |
	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
	 * Attribute 3 Type | Attribute 4 Type ...
	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	 */

	public static UnknownAttribute parse(byte[] data)
			throws MessageAttributeParsingException {
		try {
			final UnknownAttribute result = new UnknownAttribute();
			if (data.length % 4 != 0) {
				throw new MessageAttributeParsingException(
						"Data array too short");
			}
			for (int i = 0; i < data.length; i += 4) {
				final byte[] temp = new byte[4];
				System.arraycopy(data, i, temp, 0, 4);
				final long attri = Utility.fourBytesToLong(temp);
				result.addAttribute(MessageAttribute.intToType(attri));
			}
			return result;
		} catch (final UtilityException ue) {
			throw new MessageAttributeParsingException("Parsing error");
		}
	}

	Vector<MessageAttributeType> unkown = new Vector<MessageAttributeType>();

	public UnknownAttribute() {
		super(MessageAttribute.MessageAttributeType.UnknownAttribute);
	}

	public void addAttribute(MessageAttributeType attribute) {
		unkown.add(attribute);
	}

	@Override
	public byte[] getBytes() throws UtilityException {
		int length = 0;
		if (unkown.size() % 2 == 1) {
			length = 2 * (unkown.size() + 1) + 4;
		} else {
			length = 2 * unkown.size() + 4;
		}
		final byte[] result = new byte[length];
		// message attribute header
		// type
		System.arraycopy(Utility.integerToTwoBytes(typeToInteger(type)), 0,
				result, 0, 2);
		// length
		System.arraycopy(Utility.integerToTwoBytes(length - 4), 0, result, 2, 2);

		// unkown attribute header
		final Iterator<MessageAttributeType> it = unkown.iterator();
		while (it.hasNext()) {
			final MessageAttributeType attri = it.next();
			System.arraycopy(Utility.integerToTwoBytes(typeToInteger(attri)),
					0, result, 4, 2);
		}
		// padding
		if (unkown.size() % 2 == 1) {
			System.arraycopy(Utility.integerToTwoBytes(typeToInteger(unkown
					.elementAt(1))), 0, result, 4, 2);
		}
		return result;
	}
}