/// <summary>

    /// CRC校验

    /// </summary>

    public class CRC

    {

        #region  CRC16

        public static byte[] CRC16(byte[] data)

        {

            int len = data.Length;

            if (len > 0)

            {

                ushort crc = 0xFFFF;

                for (int i = 0; i < len; i++)

                {

                    crc = (ushort)(crc ^ (data[i]));

                    for (int j = 0; j < 8; j++)

                    {

                        crc = (crc & 1) != 0 ? (ushort)((crc >> 1) ^ 0xA001) : (ushort)(crc >> 1);

                    }

                }

                byte hi = (byte)((crc & 0xFF00) >> 8);  //高位置

                byte lo = (byte)(crc & 0x00FF);         //低位置

                return new byte[] { hi, lo };

            }

            return new byte[] { 0, 0 };

        }

        #endregion

        #region  ToCRC16

        public static string ToCRC16(string content)

        {

            return ToCRC16(content, Encoding.UTF8);

        }

        public static string ToCRC16(string content, bool isReverse)

        {

            return ToCRC16(content, Encoding.UTF8, isReverse);

        }

        public static string ToCRC16(string content, Encoding encoding)

        {

            return ByteToString(CRC16(encoding.GetBytes(content)), true);

        }

        public static string ToCRC16(string content, Encoding encoding, bool isReverse)

        {

            return ByteToString(CRC16(encoding.GetBytes(content)), isReverse);

        }

        public static string ToCRC16(byte[] data)

        {

            return ByteToString(CRC16(data), true);

        }

        public static string ToCRC16(byte[] data, bool isReverse)

        {

            return ByteToString(CRC16(data), isReverse);

        }

        #endregion

        #region  ToModbusCRC16

        public static string ToModbusCRC16(string s)

        {

            return ToModbusCRC16(s, true);

        }

        public static string ToModbusCRC16(string s, bool isReverse)

        {

            return ByteToString(CRC16(StringToHexByte(s)), isReverse);

        }

        public static string ToModbusCRC16(byte[] data)

        {

            return ToModbusCRC16(data, true);

        }

        public static string ToModbusCRC16(byte[] data, bool isReverse)

        {

            return ByteToString(CRC16(data), isReverse);

        }

        #endregion

        #region  ByteToString

        public static string ByteToString(byte[] arr, bool isReverse)

        {

            try

            {

                byte hi = arr[0], lo = arr[1];

                return Convert.ToString(isReverse ? hi + lo * 0x100 : hi * 0x100 + lo, 16).ToUpper().PadLeft(4, '0');

            }

            catch (Exception ex) { throw (ex); }

        }

        public static string ByteToString(byte[] arr)

        {

            try

            {

                return ByteToString(arr, true);

            }

            catch (Exception ex) { throw (ex); }

        }

        #endregion

        #region  StringToHexString

        public static string StringToHexString(string str)

        {

            StringBuilder s = new StringBuilder();

            foreach (short c in str.ToCharArray())

            {

                s.Append(c.ToString("X4"));

            }

            return s.ToString();

        }

        #endregion

        #region  StringToHexByte

        private static string ConvertChinese(string str)

        {

            StringBuilder s = new StringBuilder();

            foreach (short c in str.ToCharArray())

            {

                if (c <= 0 || c >= 127)

                {

                    s.Append(c.ToString("X4"));

                }

                else

                {

                    s.Append((char)c);

                }

            }

            return s.ToString();

        }

        private static string FilterChinese(string str)

        {

            StringBuilder s = new StringBuilder();

            foreach (short c in str.ToCharArray())

            {

                if (c > 0 && c < 127)

                {

                    s.Append((char)c);

                }

            }

            return s.ToString();

        }

        /// <summary>

        /// 字符串转16进制字符数组

        /// </summary>

        /// <param name="hex"></param>

        /// <returns></returns>

        public static byte[] StringToHexByte(string str)

        {

            return StringToHexByte(str, false);

        }

        /// <summary>

        /// 字符串转16进制字符数组

        /// </summary>

        /// <param name="str"></param>

        /// <param name="isFilterChinese">是否过滤掉中文字符</param>

        /// <returns></returns>

        public static byte[] StringToHexByte(string str, bool isFilterChinese)

        {

            string hex = isFilterChinese ? FilterChinese(str) : ConvertChinese(str);

            //清除所有空格

            hex = hex.Replace(" ", "");

            //若字符个数为奇数，补一个0

            hex += hex.Length % 2 != 0 ? "0" : "";

            byte[] result = new byte[hex.Length / 2];

            for (int i = 0, c = result.Length; i < c; i++)

            {

                result[i] = Convert.ToByte(hex.Substring(i * 2, 2), 16);

            }

            return result;

        }

        #endregion

    }