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

namespace MaterialTraceability.Common
{
    /// <summary>
    /// 校验工具类
    /// </summary>
    public class CheckUtil
    {
        /// <summary>
        /// 异或校验
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        public static int BCC(byte[] data)
        {
            int temp = 0;
            for (int index = 0; index < data.Length; index++)
            {
                temp = temp ^ data[index];
            }

            return temp;
        }

        /// <summary>
        /// CRC16_Modbus效验
        /// </summary>
        /// <param name="byteData">要进行计算的字节数组</param>
        /// <returns>计算后的数组</returns>
        public static byte[] ToModbus(byte[] byteData)
        {
            byte[] CRC = new byte[2];

            UInt16 wCrc = 0xFFFF;
            for (int i = 0; i < byteData.Length; i++)
            {
                wCrc ^= Convert.ToUInt16(byteData[i]);
                for (int j = 0; j < 8; j++)
                {
                    if ((wCrc & 0x0001) == 1)
                    {
                        wCrc >>= 1;
                        wCrc ^= 0xA001;//异或多项式
                    }
                    else
                    {
                        wCrc >>= 1;
                    }
                }
            }

            CRC[1] = (byte)((wCrc & 0xFF00) >> 8);//高位在后
            CRC[0] = (byte)(wCrc & 0x00FF);       //低位在前
            return CRC;

        }
    }
}