/*
 * Copyright (C) 2005 Alfresco, Inc.
 *
 * Licensed under the Mozilla Public License version 1.1 
 * with a permitted attribution clause. You may obtain a
 * copy of the License at
 *
 *   http://www.alfresco.org/legal/license.txt
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the
 * License.
 */
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();
    }
}