/**
 * $Id: IpAttribute.java,v 1.3 2005/09/06 16:38:41 wuttke Exp $
 * Created on 10.04.2005
 * @author Matthias Wuttke
 * @version $Revision: 1.3 $
 */
package org.tinyradius.attribute;

import java.util.StringTokenizer;

import org.tinyradius.util.RadiusException;

/**
 * This class represents a Radius attribute for an IP number.
 */
public class IpAttribute extends RadiusAttribute {

	/**
	 * Constructs an empty IP attribute.
	 */
	public IpAttribute() {
		super();
	}
	
	/**
	 * Constructs an IP attribute.
	 * @param type attribute type code
	 * @param value value, format: xx.xx.xx.xx
	 */
	public IpAttribute(int type, String value) {
		setAttributeType(type);
		setAttributeValue(value);
	}
	
	/**
	 * Constructs an IP attribute.
	 * @param type attribute type code
	 * @param ipNum value as a 32 bit unsigned int
	 */
	public IpAttribute(int type, long ipNum) {
		setAttributeType(type);
		setIpAsLong(ipNum);
	}
	
	/**
	 * Returns the attribute value (IP number) as a string of the
	 * format "xx.xx.xx.xx".
	 * @see org.tinyradius.attribute.RadiusAttribute#getAttributeValue()
	 */
	public String getAttributeValue() {
		StringBuffer ip = new StringBuffer();
		byte[] data = getAttributeData();
		if (data == null || data.length != 4)
			throw new RuntimeException("ip attribute: expected 4 bytes attribute data");
		
		ip.append(data[0] & 0x0ff);
		ip.append(".");
		ip.append(data[1] & 0x0ff);
		ip.append(".");
		ip.append(data[2] & 0x0ff);
		ip.append(".");
		ip.append(data[3] & 0x0ff);
		
		return ip.toString();
	}
	
	/**
	 * Sets the attribute value (IP number). String format:
	 * "xx.xx.xx.xx".
	 * @throws IllegalArgumentException
	 * @throws NumberFormatException
	 * @see org.tinyradius.attribute.RadiusAttribute#setAttributeValue(java.lang.String)
	 */
	public void setAttributeValue(String value) {
		if (value == null || value.length() < 7 || value.length() > 15)
			throw new IllegalArgumentException("bad IP number");
		
		StringTokenizer tok = new StringTokenizer(value, ".");
		if (tok.countTokens() != 4)
			throw new IllegalArgumentException("bad IP number: 4 numbers required");
		
		byte[] data = new byte[4];
		for (int i = 0; i < 4; i++) {
			int num = Integer.parseInt(tok.nextToken());
			if (num < 0 || num > 255)
				throw new IllegalArgumentException("bad IP number: num out of bounds");
			data[i] = (byte)num;
		}
		
		setAttributeData(data);
	}
	
	/**
	 * Returns the IP number as a 32 bit unsigned number. The number is
	 * returned in a long because Java does not support unsigned ints.
	 * @return IP number
	 */
	public long getIpAsLong() {
		byte[] data = getAttributeData();
		if (data == null || data.length != 4)
			throw new RuntimeException("expected 4 bytes attribute data");
		return ((long)(data[0] & 0x0ff)) << 24 | (data[1] & 0x0ff) << 16 |
			   (data[2] & 0x0ff) << 8 | (data[3] & 0x0ff);
	}
	
	/**
	 * Sets the IP number represented by this IpAttribute
	 * as a 32 bit unsigned number.
	 * @param ip
	 */
	public void setIpAsLong(long ip) {
		byte[] data = new byte[4];
		data[0] = (byte)((ip >> 24) & 0x0ff);
		data[1] = (byte)((ip >> 16) & 0x0ff);
		data[2] = (byte)((ip >> 8) & 0x0ff);
		data[3] = (byte)(ip & 0x0ff);
		setAttributeData(data);
	}

	/**
	 * Check attribute length.
	 * @see org.tinyradius.attribute.RadiusAttribute#readAttribute(byte[], int, int)
	 */
	public void readAttribute(byte[] data, int offset, int length)
	throws RadiusException {
		if (length != 6)
			throw new RadiusException("IP attribute: expected 4 bytes data");
		super.readAttribute(data, offset, length);
	}

}