CRC-8校验算法

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publicenum CRC8_POLY
  {
      CRC8 =0xd5,
      CRC8_CCIIT =0x07,
      CRC8_DALLAS_MAXIM =0x31,
      CRC8_SAE_J1850 =0x1d,
      CRC_8_WCDMA =0x9b,
     
  };
    publicclass CRC8Calc
    {
        privatebyte[] table =newbyte[256];
        publicbyte Checksum(paramsbyte[] val)
        {
            if (val ==null)
                thrownew ArgumentNullException("Val");
            byte c =0;
            foreach (byte b in val)
                c = table[c ^ b];
            return c;
        }
        publicbyte[] Table
        {
            get
            {
                returnthis.table;
            }
            set
            {
                table = value;
            }
           
        }

        publicbyte[] GenerateTable(CRC8_POLY polynomial)
        {
            byte[] csTable =newbyte[256];
            for (int i =0; i <256; ++i)
            {
                int curr = i;
                for (int j =0; j <8; ++j)
                {
                    if ((curr &0x80) !=0)
                        curr = (curr <<1) ^ (int)polynomial;
                    else
                        curr <<=1;
                }
                csTable[i] = (byte)curr;
            }
            return csTable;
        }

        public CRC8Calc(CRC8_POLY polynomial)
        {
            this.table =this.GenerateTable(polynomial);
        }

    }

    class Program
    {
      staticvoid Main(string[] args)
        {

         RunSnippet();

        }

        
        publicstaticvoid RunSnippet()
        {
            byte checksum;
            byte[] testVal =newbyte[] { 0x01};
            CRC8Calc crc =new CRC8Calc(CRC8_POLY.CRC8_DALLAS_MAXIM);
            checksum = crc.Checksum(testVal);
            WL(checksum);
            Console.ReadKey();

        }

        publicstaticvoid WL(object text, paramsobject[] args)
        {
            Console.WriteLine(text.ToString(), args);
        }
    }

staticbyte CheckValue(byte[] b, int len)
        {
            byte crc =0;
            byte j =0;
            while (len --!=0)
            {
                for (byte i =0x80; i !=0; i >>=1)
                {
                                                    
                    if ((crc & MSB_MASK_8) !=0)    //  1 0 0 0    0 0 0 0   判断crc中得最高位是否为1
                    {                             // 如果crc中得最高位为1，就执行以下语句,与R_8做XOR运算
                           crc <<=1;                //
                        crc &= LIMIT_MASK_8; // 1 1 1 1   1 1 1 1
                        crc ^= R_8;
                    }
                    else
                        crc <<=1;
                    if ((b[j] & i) !=0)     // 每循环一次，从数据的最高位依次取到最低位，如果取得的数据位为1,就执行以下语句
                           crc ^= R_8;         //      1 0 0 1  1 0 1 1 
                  

                }
                j++;
            }
            return crc;