/*
 * Copyright (C) 2005 Alfresco, Inc.
 *
 * 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"
 */
package org.alfresco.filesys.util;

import java.net.InetAddress;
import java.util.StringTokenizer;

/**
 * TCP/IP Address Utility Class
 */
public class IPAddress
{

    /**
     * Check if the specified address is a valid numeric TCP/IP address
     * 
     * @param ipaddr String
     * @return boolean
     */
    public final static boolean isNumericAddress(String ipaddr)
    {

        // Check if the string is valid

        if (ipaddr == null || ipaddr.length() < 7 || ipaddr.length() > 15)
            return false;

        // Check the address string, should be n.n.n.n format

        StringTokenizer token = new StringTokenizer(ipaddr, ".");
        if (token.countTokens() != 4)
            return false;

        while (token.hasMoreTokens())
        {

            // Get the current token and convert to an integer value

            String ipNum = token.nextToken();

            try
            {
                int ipVal = Integer.valueOf(ipNum).intValue();
                if (ipVal < 0 || ipVal > 255)
                    return false;
            }
            catch (NumberFormatException ex)
            {
                return false;
            }
        }

        // Looks like a valid IP address

        return true;
    }

    /**
     * Check if the specified address is a valid numeric TCP/IP address and return as an integer
     * value
     * 
     * @param ipaddr String
     * @return int
     */
    public final 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;
    }

    /**
     * Convert an IP address into an integer value
     * 
     * @param ipaddr InetAddress
     * @return int
     */
    public final static int asInteger(InetAddress ipaddr)
    {

        // Get the address as an array of bytes

        byte[] addrBytes = ipaddr.getAddress();

        // Build an integer value from the bytes

        return DataPacker.getInt(addrBytes, 0);
    }

    /**
     * Check if the specified address is within the required subnet
     * 
     * @param ipaddr String
     * @param subnet String
     * @param mask String
     * @return boolean
     */
    public final static boolean isInSubnet(String ipaddr, String subnet, String mask)
    {

        // Convert the addresses to integer values

        int ipaddrInt = parseNumericAddress(ipaddr);
        if (ipaddrInt == 0)
            return false;

        int subnetInt = parseNumericAddress(subnet);
        if (subnetInt == 0)
            return false;

        int maskInt = parseNumericAddress(mask);
        if (maskInt == 0)
            return false;

        // Check if the address is part of the subnet

        if ((ipaddrInt & maskInt) == subnetInt)
            return true;
        return false;
    }

    /**
     * Convert a raw IP address array as a String
     * 
     * @param ipaddr byte[]
     * @return String
     */
    public final static String asString(byte[] ipaddr)
    {

        // Check if the address is valid

        if (ipaddr == null || ipaddr.length != 4)
            return null;

        // Convert the raw IP address to a string

        StringBuffer str = new StringBuffer();

        str.append((int) (ipaddr[0] & 0xFF));
        str.append(".");
        str.append((int) (ipaddr[1] & 0xFF));
        str.append(".");
        str.append((int) (ipaddr[2] & 0xFF));
        str.append(".");
        str.append((int) (ipaddr[3] & 0xFF));

        // Return the address string

        return str.toString();
    }
}