C# CRC16 CCITT TABLE 範例

GITHUB: https://github.com/jash-git/CS-CRC16-CCITT-TABLE

由於要和具有CRC16的硬體設備通訊，看完就有的BCB6 CODE之後，自己在C#實作一個小範例

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CS_crc16_CCITT_TABLE
{
    //資料來源:http://stackoverflow.com/questions/5059268/c-sharp-crc-implementation
    public class Crc16CcittKermit
    {
        private static ushort[] table = {
      0x0000, 0x1189, 0x2312, 0x329B, 0x4624, 0x57AD, 0x6536, 0x74BF,
      0x8C48, 0x9DC1, 0xAF5A, 0xBED3, 0xCA6C, 0xDBE5, 0xE97E, 0xF8F7,
      0x1081, 0x0108, 0x3393, 0x221A, 0x56A5, 0x472C, 0x75B7, 0x643E,
      0x9CC9, 0x8D40, 0xBFDB, 0xAE52, 0xDAED, 0xCB64, 0xF9FF, 0xE876,
      0x2102, 0x308B, 0x0210, 0x1399, 0x6726, 0x76AF, 0x4434, 0x55BD,
      0xAD4A, 0xBCC3, 0x8E58, 0x9FD1, 0xEB6E, 0xFAE7, 0xC87C, 0xD9F5,
      0x3183, 0x200A, 0x1291, 0x0318, 0x77A7, 0x662E, 0x54B5, 0x453C,
      0xBDCB, 0xAC42, 0x9ED9, 0x8F50, 0xFBEF, 0xEA66, 0xD8FD, 0xC974,
      0x4204, 0x538D, 0x6116, 0x709F, 0x0420, 0x15A9, 0x2732, 0x36BB,
      0xCE4C, 0xDFC5, 0xED5E, 0xFCD7, 0x8868, 0x99E1, 0xAB7A, 0xBAF3,
      0x5285, 0x430C, 0x7197, 0x601E, 0x14A1, 0x0528, 0x37B3, 0x263A,
      0xDECD, 0xCF44, 0xFDDF, 0xEC56, 0x98E9, 0x8960, 0xBBFB, 0xAA72,
      0x6306, 0x728F, 0x4014, 0x519D, 0x2522, 0x34AB, 0x0630, 0x17B9,
      0xEF4E, 0xFEC7, 0xCC5C, 0xDDD5, 0xA96A, 0xB8E3, 0x8A78, 0x9BF1,
      0x7387, 0x620E, 0x5095, 0x411C, 0x35A3, 0x242A, 0x16B1, 0x0738,
      0xFFCF, 0xEE46, 0xDCDD, 0xCD54, 0xB9EB, 0xA862, 0x9AF9, 0x8B70,
      0x8408, 0x9581, 0xA71A, 0xB693, 0xC22C, 0xD3A5, 0xE13E, 0xF0B7,
      0x0840, 0x19C9, 0x2B52, 0x3ADB, 0x4E64, 0x5FED, 0x6D76, 0x7CFF,
      0x9489, 0x8500, 0xB79B, 0xA612, 0xD2AD, 0xC324, 0xF1BF, 0xE036,
      0x18C1, 0x0948, 0x3BD3, 0x2A5A, 0x5EE5, 0x4F6C, 0x7DF7, 0x6C7E,
      0xA50A, 0xB483, 0x8618, 0x9791, 0xE32E, 0xF2A7, 0xC03C, 0xD1B5,
      0x2942, 0x38CB, 0x0A50, 0x1BD9, 0x6F66, 0x7EEF, 0x4C74, 0x5DFD,
      0xB58B, 0xA402, 0x9699, 0x8710, 0xF3AF, 0xE226, 0xD0BD, 0xC134,
      0x39C3, 0x284A, 0x1AD1, 0x0B58, 0x7FE7, 0x6E6E, 0x5CF5, 0x4D7C,
      0xC60C, 0xD785, 0xE51E, 0xF497, 0x8028, 0x91A1, 0xA33A, 0xB2B3,
      0x4A44, 0x5BCD, 0x6956, 0x78DF, 0x0C60, 0x1DE9, 0x2F72, 0x3EFB,
      0xD68D, 0xC704, 0xF59F, 0xE416, 0x90A9, 0x8120, 0xB3BB, 0xA232,
      0x5AC5, 0x4B4C, 0x79D7, 0x685E, 0x1CE1, 0x0D68, 0x3FF3, 0x2E7A,
      0xE70E, 0xF687, 0xC41C, 0xD595, 0xA12A, 0xB0A3, 0x8238, 0x93B1,
      0x6B46, 0x7ACF, 0x4854, 0x59DD, 0x2D62, 0x3CEB, 0x0E70, 0x1FF9,
      0xF78F, 0xE606, 0xD49D, 0xC514, 0xB1AB, 0xA022, 0x92B9, 0x8330,
      0x7BC7, 0x6A4E, 0x58D5, 0x495C, 0x3DE3, 0x2C6A, 0x1EF1, 0x0F78
    };

        public static ushort ComputeChecksum(params byte[] buffer)
        {
            if (buffer == null) throw new ArgumentNullException();
            ushort crc = 0;
            for (int i = 0; i < buffer.Length; ++i)
            {
                crc = (ushort)((crc >> 8) ^ table[(crc ^ buffer[i]) & 0xff]);
            }
            return crc;
        }

        public static byte[] ComputeChecksumBytes(params byte[] buffer)
        {
            return BitConverter.GetBytes(ComputeChecksum(buffer));
        }
    }
}

Crc16.cs 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CS_crc16_CCITT_TABLE
{
    public class Crc16ARC
    {
        //http://sanity-free.org/134/standard_crc_16_in_csharp.html
        const ushort polynomial = 0xA001;
        ushort[] table = new ushort[256];

        public ushort ComputeChecksum(byte[] bytes)
        {
            ushort crc = 0;
            for (int i = 0; i < bytes.Length; ++i)
            {
                byte index = (byte)(crc ^ bytes[i]);
                crc = (ushort)((crc >> 8) ^ table[index]);
            }
            return crc;
        }

        public byte[] ComputeChecksumBytes(byte[] bytes)
        {
            ushort crc = ComputeChecksum(bytes);
            return BitConverter.GetBytes(crc);
        }

        public Crc16ARC()
        {
            ushort value;
            ushort temp;
            for (ushort i = 0; i < table.Length; ++i)
            {
                value = 0;
                temp = i;
                for (byte j = 0; j < 8; ++j)
                {
                    if (((value ^ temp) & 0x0001) != 0)
                    {
                        value = (ushort)((value >> 1) ^ polynomial);
                    }
                    else
                    {
                        value >>= 1;
                    }
                    temp >>= 1;
                }
                table[i] = value;
            }
        }
    }

    public class CRC16_MODBUS
    {
        //https://www.itread01.com/content/1549066714.html
        public static UInt16 Cal_crc16(byte[] data, int size)
        {

            UInt32 i = 0;
            UInt16 crc = 0;
            for (i = 0; i < size; i++)
            {
                crc = UpdateCRC16(crc, data[i]);
            }
            crc = UpdateCRC16(crc, 0);
            crc = UpdateCRC16(crc, 0);

            return (UInt16)(crc);
        }
        public static UInt16 UpdateCRC16(UInt16 crcIn, byte bytee)
        {
            UInt32 crc = crcIn;
            UInt32 ins = (UInt32)bytee | 0x100;

            do
            {
                crc <<= 1;
                ins <<= 1;
                if ((ins & 0x100) == 0x100)
                {
                    ++crc;
                }
                if ((crc & 0x10000) == 0x10000)
                {
                    crc ^= 0x1021;
                }
            }
            while (!((ins & 0x10000) == 0x10000));
            return (UInt16)crc;
        }
    }
    public class Crc16
    {
        //Figure 2.7 – C Language implementation of the CRC calculation
        public static long calcrc16(byte[] dataP)
        {
	        int i, j; // Byte counter, bit counter
	        long crc16; // calculation
	        crc16 = 0000; // PRESET value
            for (i = 0; i < dataP.Length; i++) // check each Byte in the array
	        {
                crc16 ^= dataP[i];
		        for (j = 0; j < 8; j++) // test each bit in the Byte
		        {
                    if (crc16%2==1)//(crc16 & 0x0001 )
			        {
				        crc16 >>= 1;
				        crc16 ^= 0x8408; // POLYNOMIAL x^16 + x^12 + x^5 + 1
			        }
			        else
			        {
				        crc16 >>= 1;
			        }
		        }
	        }
	        return( crc16 ); // returns calculated crc (16 bits)
        }
    }
}

Program.cs 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CS_crc16_CCITT_TABLE
{
    class Program
    {
        static byte[] HexToBytes(string input)
        {
            byte[] result = new byte[input.Length / 2];
            for (int i = 0; i < result.Length; i++)
            {
                result[i] = Convert.ToByte(input.Substring(2 * i, 2), 16);
            }
            return result;
        }
        static void pause()
        {
            Console.Write("Press any key to continue . . . ");
            Console.ReadKey(true);
        }
        static void Main(string[] args)
        {
            string input = "000680010003";
            byte[] bytes = HexToBytes(input);
            string hex = Crc16CcittKermit.ComputeChecksum(bytes).ToString("x2"); ;
            Console.WriteLine("crc16_CCITT_TABLE  =>  "+hex);

            string input1 = "000680010002";
            byte[] bytes1 = HexToBytes(input1);
            string hex1 = Crc16CcittKermit.ComputeChecksum(bytes1).ToString("x2"); ;
            Console.WriteLine("crc16_CCITT_TABLE  =>  " + hex1);
            //*

            byte[] bytes2 = new byte[] { 0x01, 0x30, 0x30, 0x30, 0x31, 0x44, 0x52, 0x30, 0x35, 0x30, 0x30, 0x32, 0x36, 0x38, 0x38, 0x30, 0x30, 0x30, 0x34, 0x33, 0x41, 0x30, 0x30, 0x30, 0x35, 0x32, 0x32, 0x31, 0x37, 0x35, 0x30, 0x31, 0x31, 0x30, 0x32, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x32, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x02 };
            Crc16ARC Crc16ARC = new Crc16ARC();
            //string hex2 = CRC16_MODBUS.Cal_crc16(bytes2, bytes2.Length).ToString("x2");
            string hex2 = Crc16ARC.ComputeChecksum(bytes2).ToString("x2");
            byte[] bytesAns = Crc16ARC.ComputeChecksumBytes(bytes2);
            Console.WriteLine("Crc16ARC  =>  " + hex2);

            string hex3 = Crc16.calcrc16(bytes).ToString("x2");
            Console.WriteLine("Crc16 =>  " + hex3);

            string hex4 = Crc16.calcrc16(bytes1).ToString("x2");
            Console.WriteLine("Crc16 =>  " + hex4);

            string hex5 = Crc16.calcrc16(bytes2).ToString("x2");
            Console.WriteLine("Crc16 =>  " + hex5);
            //*/ 
            /*
            //crc16 online
            //https://emn178.github.io/online-tools/crc16.html
            000680010003 => 81d1
            */
            pause();
        }
    }
}