IPAddressTool.java

/*
 * This file is part of the OdinMS Maple Story Server Copyright (C) 2008 ~ 2010
 * Patrick Huy <patrick.huy@frz.cc> Matthias Butz <matze@odinms.de> Jan
 * Christian Meyer <vimes@odinms.de>
 * 
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Affero General Public License version 3 as published by
 * the Free Software Foundation. You may not use, modify or distribute this
 * program under any other version of the GNU Affero General Public License.
 * 
 * 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 Affero General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package javastory.tools;

/**
 * Provides a class with tools for working with IP addresses, in both strings
 * and as long integers.
 * 
 * @author Nol888
 * @version 0.1
 * @since Revision 890
 */
public class IPAddressTool {

	/**
	 * Converts a dotted-quad IP (<code>127.0.0.1</code>) and turns it into a
	 * long integer IP.
	 * 
	 * @param dottedQuad
	 *            The IP address in dotted-quad form.
	 * @return The IP as a long integer.
	 * @throws RuntimeException
	 */
	public static final long dottedQuadToLong(final String dottedQuad) throws RuntimeException {
		final String[] quads = dottedQuad.split("\\.");
		if (quads.length != 4) {
			throw new RuntimeException("Invalid IP Address format.");
		}
		long ipAddress = 0;
		for (int i = 0; i < 4; i++) {
			ipAddress += Integer.parseInt(quads[i]) % 256 * (long) Math.pow(256, 4 - i);
		}
		return ipAddress;
	}

	/**
	 * Converts a long integer IP into a dotted-quad IP.
	 * 
	 * @param longIP
	 *            The IP as a long integer.
	 * @return The IP as a dotted-quad string.
	 * @throws RuntimeException
	 */
	public static final String longToDottedQuad(long longIP) throws RuntimeException {
		final StringBuilder ipAddress = new StringBuilder();

		for (int i = 0; i < 4; i++) {
			final int quad = (int) (longIP / (long) Math.pow(256, 4 - i));
			longIP -= quad * (long) Math.pow(256, 4 - i);
			if (i > 0) {
				ipAddress.append(".");
			}
			if (quad > 255) {
				throw new RuntimeException("Invalid long IP address.");
			}
			ipAddress.append(quad);
		}

		return ipAddress.toString();
	}
}