查表法计算CRC

(查表法)CRC检验码的计算过程
(1)将上次计算出的CRC校验码右移一个字节;
(2)将移出的这个字节与新的要校验的字节进行XOR 运算;
(3)用运算出的值在预先生成码表中进行索引,获取对应的值(称为余式);
(4)用获取的值与第(1)步右移后的值进行XOR 运算;
(5)如果要校验的数据已经处理完,则第(4)步的结果就是最终的CRC校验码。如果还有数据 要进行处理,则再转到第(1)步运行。
  public static byte GetCRC8(byte[] data, int startIndex, int dataLength)
        {
            if (data == null)
                throw new ArgumentNullException("数组不能为空");
            if (startIndex > data.Length)
                throw new ArgumentException("起始索引超出数组长度");
            if (startIndex < 0)
                throw new ArgumentOutOfRangeException("起始索引不应该小于0");
            byte result = 0;
            for (int i = 0; i < dataLength; i++)
            {
                result = CRC8_TABLE[(byte)result ^ data[startIndex + i]];
            }
            return result;
        }
 public static byte GetCRC16(byte[] data, int startIndex, int dataLength)
        {
            if (data == null)
                throw new ArgumentNullException("数组不能为空");
            if (startIndex > data.Length)
                throw new ArgumentException("起始索引超出数组长度");
            if (startIndex < 0)
                throw new ArgumentOutOfRangeException("起始索引不应该小于0");
            UInt16 result = 0;
            for (int i = 0; i < dataLength; i++)
            {
                result = (UInt16)(((result >> 8)) ^ CRC16_TABLE[(byte)(data[startIndex + i] ^ result)]);
            }
            return result;
        }
         #region CRC表
        ///
        /// 8位CRC表
        ///

        static readonly byte[] CRC8_TABLE = new byte[]
        {
           0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,
           0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,
           0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
           0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,
           0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5,
           0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
           0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85,
           0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,
           0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
           0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,
           0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2,
           0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
           0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32,
           0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,
           0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
           0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A,
           0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C,
           0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
           0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC,
           0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4,
           0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,
           0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44,
           0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C,
           0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
           0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B,
           0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63,
           0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,
           0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13,
           0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB,
           0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
           0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB,
           0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3
        };
        static readonly ushort[] CRC16_TABLE = new ushort[]
        {
             0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
             0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
             0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
             0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
             0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
             0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
             0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
             0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
             0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
             0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
             0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
             0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
             0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
             0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
             0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
             0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
             0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
             0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
             0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
             0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
             0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
             0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
             0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
             0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
             0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
             0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
             0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
             0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
             0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
             0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
             0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
             0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
         };

        #endregion

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