ASP.NET实现根据IP获取省市地址的方法

            try
            {
                objfs.Position = 0;
                byte[] buff = new Byte[8];
                objfs.Read(buff, 0, 8);
                firstStartIp = buff[0] + buff[1] * 256 + buff[2] * 256 * 256 + buff[3] * 256 * 256 * 256;
                lastStartIp = buff[4] * 1 + buff[5] * 256 + buff[6] * 256 * 256 + buff[7] * 256 * 256 * 256;
                long recordCount = Convert.ToInt64((lastStartIp - firstStartIp) / 7.0);
                if (recordCount <= 1)
                {
                    country = "FileDataError";
                    objfs.Close();
                    return 2;
                }
                long rangE = recordCount;
                long rangB = 0;
                long recNO = 0;
                while (rangB < rangE - 1)
                {
                    recNO = (rangE + rangB) /2;
                    this.GetStartIp(recNO);
                    if (ip_Int ==this.startIp)
                    {
                        rangB = recNO;