package se.leap.bitmaskclient.utils;

/*
 * Copyright (C) 2006-2008 Alfresco Software Limited.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * 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 General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 * As a special exception to the terms and conditions of version 2.0 of
 * the GPL, you may redistribute this Program in connection with Free/Libre
 * and Open Source Software ("FLOSS") applications as described in Alfresco's
 * FLOSS exception.  You should have recieved a copy of the text describing
 * the FLOSS exception, and it is also available here:
 * http://www.alfresco.com/legal/licensing"
 */

import java.util.StringTokenizer;

/**
 * TCP/IP Address Utility Class
 *
 * @author gkspencer
 */
public class IPAddress {


    /**
     * Convert a TCP/IP address string into a byte array
     *
     * @param addr String
     * @return byte[]
     */
    public static byte[] asBytes(String addr) {

        // Convert the TCP/IP address string to an integer value
        int ipInt = parseNumericAddress(addr);
        if (ipInt == 0)
            return null;

        // Convert to bytes
        byte[] ipByts = new byte[4];

        ipByts[3] = (byte) (ipInt & 0xFF);
        ipByts[2] = (byte) ((ipInt >> 8) & 0xFF);
        ipByts[1] = (byte) ((ipInt >> 16) & 0xFF);
        ipByts[0] = (byte) ((ipInt >> 24) & 0xFF);

        // Return the TCP/IP bytes
        return ipByts;
    }
    /**
     * Check if the specified address is a valid numeric TCP/IP address and return as an integer value
     *
     * @param ipaddr String
     * @return int
     */
    private static int parseNumericAddress(String ipaddr) {

        //  Check if the string is valid
        if (ipaddr == null || ipaddr.length() < 7 || ipaddr.length() > 15)
            return 0;

        //  Check the address string, should be n.n.n.n format
        StringTokenizer token = new StringTokenizer(ipaddr,".");
        if (token.countTokens() != 4)
            return 0;

        int ipInt = 0;
        while (token.hasMoreTokens()) {

            //  Get the current token and convert to an integer value
            String ipNum = token.nextToken();

            try {
                //  Validate the current address part
                int ipVal = Integer.valueOf(ipNum).intValue();
                if (ipVal < 0 || ipVal > 255)
                    return 0;

                //  Add to the integer address
                ipInt = (ipInt << 8) + ipVal;
            }
            catch (NumberFormatException ex) {
                return 0;
            }
        }

        //  Return the integer address
        return ipInt;
    }
}