89 lines
2.5 KiB
C#
89 lines
2.5 KiB
C#
using System;
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namespace ModBus.Net
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{
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public class Crc16
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{
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/// <summary>
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/// CRC验证表
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/// </summary>
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public byte[] crc_table = new byte[512];
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private static Crc16 _crc16 = null;
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public static Crc16 GetInstance()
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{
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if (_crc16 == null)
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{
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_crc16 = new Crc16();
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}
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return _crc16;
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}
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#region 生成CRC码
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/// <summary>
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/// 生成CRC码
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/// </summary>
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/// <param name="message">发送或返回的命令，CRC码除外</param>
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/// <param name="CRC">生成的CRC码</param>
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public short GetCRC(byte[] message, ref byte[] Rcvbuf)
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{
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int IX,IY,CRC;
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int Len = message.Length;
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CRC=0xFFFF;
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//set all 1
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if (Len<=0)
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CRC = 0;
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else
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{
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Len--;
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for (IX=0;IX<=Len;IX++)
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{
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CRC=CRC^(message[IX]);
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for(IY=0;IY<=7;IY++)
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{
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if ((CRC&1)!=0 )
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CRC=(CRC>>1)^0xA001;
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else
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CRC=CRC>>1;
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//
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}
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}
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}
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Rcvbuf[1] = (byte)((CRC & 0xff00)>>8);//高位置
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Rcvbuf[0] = (byte)(CRC & 0x00ff); //低位置
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CRC= Rcvbuf[0]<<8;
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CRC+= Rcvbuf[1];
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return (short)CRC;
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}
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#endregion
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#region CRC验证
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/// <summary>
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/// CRC校验
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/// </summary>
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/// <param name="src">ST开头，&&结尾</param>
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/// <returns>十六进制数</returns>
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public bool CrcEfficacy(byte[] byteframe)
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{
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byte[] recvbuff = new byte[2];
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byte[] byteArr = new byte[byteframe.Length - 2];
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Array.Copy(byteframe, 0, byteArr, 0, byteArr.Length);
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GetCRC(byteArr, ref recvbuff);
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if (recvbuff[0] == byteframe[byteframe.Length - 2] && recvbuff[1] == byteframe[byteframe.Length - 1])
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{
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return true;
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}
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else
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{
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return false;
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}
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}
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#endregion
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}
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}
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