/*
 *
 * (c) Copyright Ascensio System Limited 2010-2018
 *
 * This program is freeware. You can redistribute it and/or modify it under the terms of the GNU 
 * General Public License (GPL) version 3 as published by the Free Software Foundation (https://www.gnu.org/copyleft/gpl.html). 
 * In accordance with Section 7(a) of the GNU GPL its Section 15 shall be amended to the effect that 
 * Ascensio System SIA expressly excludes the warranty of non-infringement of any third-party rights.
 *
 * THIS PROGRAM IS DISTRIBUTED WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY OR
 * FITNESS FOR A PARTICULAR PURPOSE. For more details, see GNU GPL at https://www.gnu.org/copyleft/gpl.html
 *
 * You can contact Ascensio System SIA by email at sales@onlyoffice.com
 *
 * The interactive user interfaces in modified source and object code versions of ONLYOFFICE must display 
 * Appropriate Legal Notices, as required under Section 5 of the GNU GPL version 3.
 *
 * Pursuant to Section 7 § 3(b) of the GNU GPL you must retain the original ONLYOFFICE logo which contains 
 * relevant author attributions when distributing the software. If the display of the logo in its graphic 
 * form is not reasonably feasible for technical reasons, you must include the words "Powered by ONLYOFFICE" 
 * in every copy of the program you distribute. 
 * Pursuant to Section 7 § 3(e) we decline to grant you any rights under trademark law for use of our trademarks.
 *
*/


using System.Net;
using System.Net.Sockets;

namespace ASC.IPSecurity
{
    class IPAddressRange
    {
        private readonly AddressFamily addressFamily;
        private readonly byte[] lowerBytes;
        private readonly byte[] upperBytes;

        public IPAddressRange(IPAddress lower, IPAddress upper)
        {
            addressFamily = lower.AddressFamily;
            lowerBytes = lower.GetAddressBytes();
            upperBytes = upper.GetAddressBytes();
        }

        public bool IsInRange(IPAddress address)
        {
            if (address.AddressFamily != addressFamily)
            {
                return false;
            }

            var addressBytes = address.GetAddressBytes();

            bool lowerBoundary = true, upperBoundary = true;

            for (var i = 0; i < lowerBytes.Length &&
                            (lowerBoundary || upperBoundary); i++)
            {
                if ((lowerBoundary && addressBytes[i] < lowerBytes[i]) || (upperBoundary && addressBytes[i] > upperBytes[i]))
                {
                    return false;
                }

                lowerBoundary &= (addressBytes[i] == lowerBytes[i]);
                upperBoundary &= (addressBytes[i] == upperBytes[i]);
            }

            return true;
        }
    }
}