using System;

public class Program

{

        const int INIT_VALUE = 0;

        private long lngValue;

​

        private long[] CRC16Table = new long[257];

​

        public void Crc16Checksum()

        {

            lngValue = INIT_VALUE;

            InitCRC();

        }

​

        public long GetValue()

        {

            return lngValue;

        }

​

        public void SetValue(int v)

        {

            lngValue = v;

        }

​

        public void InitCRC()

        {

            int i = 0;

            int j = 0;

            long K = 0;

            long crc = 0;

​

            lngValue = INIT_VALUE;

            for (i = 0; i <= 255; i++)

            {

                K = (i * 256L) & 65535;

                crc = 0;

                for (j = 0; j <= 7; j++)

                {

                    if (((crc ^ K) & 0x8000L) != 0)

                    {

                        //Console.WriteLine("a"+((crc ^ K) & 0x8000L));

                        crc = ((crc * 2) & 65535) ^ 0x1021L;

                    }

                    else

                    {

                        //Console.WriteLine("b"+((crc ^ K) & 0x8000L));

                        crc = (crc * 2) & 65535;

                    }

                    K = (K * 2) & 65535;

                }

                CRC16Table[i] = crc;

            }

        }

​

        public long Update(int v)

        {

            //Console.WriteLine(v);

            long lngValue1 = 0;

            long lngValue2 = 0;

            long lngValue3 = 0;

​

            lngValue1 = ((lngValue & 0xff00L) / 256) & 0xffL;

            //Console.WriteLine(lngValue1);

            lngValue1 = CRC16Table[lngValue1];

            //Console.WriteLine(CRC16Table[lngValue1]);

            lngValue2 = ((lngValue & 0xffL) * 256L) & 0xff00L;

            lngValue3 = v & 0xffL;

            lngValue = lngValue1 ^ lngValue2 ^ lngValue3;

​

            return lngValue;

        }

​

        public long UpdateString(string message)

        {

            int intLen = 0;

            int i = 0;

            long lngRet = 0;

​

            intLen = message.Length;

            for (i = 0; i < intLen; i++)

            {

                Console.WriteLine((Int)System.Convert.ToChar(message.Substring(i, 1)));

                lngRet = Update((int)System.Convert.ToChar(message.Substring(i, 1)));

                Console.WriteLine(lngRet);

            }

            return lngRet;

        }

    public static void Main()

    {

        Program xyz = new Program();

        xyz.Crc16Checksum();

        //long us = xyz.UpdateString("ABC");

        //Console.WriteLine(us);

        long lng = xyz.Update(272727);

        Console.WriteLine(lng);

        //foreach (var item in xyz.CRC16Table) {

            //Console.WriteLine(item);

        //}

        xyz.UpdateString("String");

        string str = "String";

        Console.WriteLine(str.Substring(0,1));

    }

}