CRC即循环冗余校验码（Cyclic Redundancy Check）：是数据通信领域中最常用的一种查错校验码，其特征是信息字段和校验字段的长度可以任意选定。循环冗余检查（CRC）是一种数据传输检错功能，对数据进行多项式计算，并将得到的结果附在帧的后面，接收设备也执行类似的算法，以保证数据传输的正确性和完整性。
/// CRC算法参数模型解释：
/// NAME：参数模型名称。
///WIDTH：宽度，即CRC比特数。
/// POLY：生成项的简写，以16进制表示。例如：CRC-32即是0x04C11DB7，忽略了最高位的"1"，即完整的生成项是0x104C11DB7。
///INIT：这是算法开始时寄存器（crc）的初始化预置值，十六进制表示。
///REFIN：待测数据的每个字节是否按位反转，True或False。
/// REFOUT：在计算后之后，异或输出之前，整个数据是否按位反转，True或False。
/// XOROUT：计算结果与此参数异或后得到最终的CRC值。
/// **********************************************************************
/// Name: CRC-4/ITU x4+x+1
/// Poly: 0x03
/// Init: 0x00
/// Refin: true
/// Refout: true
/// Xorout: 0x00
///*************************************************************************
public static byte[] Crc1(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (byte)((crc >> ) ^ 0x0C);//0x0C = (reverse 0x03)>>(8-4)
else
crc = (byte)(crc >> );
}
}
return new byte[] { crc };
}
/// **********************************************************************
/// Name: CRC-5/EPC x5+x3+1
/// Poly: 0x09
/// Init: 0x09
/// Refin: false
/// Refout: false
/// Xorout: 0x00
///*************************************************************************
public static byte[] Crc2(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte crc = 0x48;// Initial value: 0x48 = 0x09<<(8-5)
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & 0x80) > )
crc = (byte)((crc << ) ^ 0x48);// 0x48 = 0x09<<(8-5)
else
crc = (byte)(crc << );
}
}
return new byte[] { (byte)(crc >> ) };
}
/// **********************************************************************
/// Name: CRC-5/ITU x5+x4+x2+1
/// Poly: 0x15
/// Init: 0x00
/// Refin: true
/// Refout: true
/// Xorout: 0x00
///*************************************************************************
public static byte[] Crc3(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (byte)((crc >> ) ^ 0x15);// 0x15 = (reverse 0x15)>>(8-5)
else
crc = (byte)(crc >> );
}
}
return new byte[] { crc };
}
/// **********************************************************************
/// Name: CRC-5/USB x5+x2+1
/// Poly: 0x05
/// Init: 0x1F
/// Refin: true
/// Refout: true
/// Xorout: 0x1F
///*************************************************************************
public static byte[] Crc4(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte crc = 0x1F;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (byte)((crc >> ) ^ 0x14);// 0x14 = (reverse 0x05)>>(8-5)
else
crc = (byte)(crc >> );
}
}
return new byte[] {(byte)( crc ^ 0x1F) };
}
/// **********************************************************************
/// Name: CRC-6/ITU x6+x+1
/// Poly: 0x03
/// Init: 0x00
/// Refin: true
/// Refout: true
/// Xorout: 0x00
///*************************************************************************
public static byte[] Crc5(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (byte)((crc >> ) ^ 0x30);// 0x30 = (reverse 0x03)>>(8-6)
else
crc = (byte)(crc >> );
}
}
return new byte[] { crc };
}
/// **********************************************************************
/// Name: CRC-7/MMC x7+x3+1
/// Poly: 0x09
/// Init: 0x00
/// Refin: false
/// Refout: false
/// Xorout: 0x00
///*************************************************************************
public static byte[] Crc6(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & 0x80) > )
crc = (byte)((crc << ) ^ 0x12);// 0x12 = 0x09<<(8-7)
else
crc = (byte)(crc << );
}
}
return new byte[] { (byte)(crc >> ) };
}
/// **********************************************************************
/// Name: CRC8 x8+x2+x+1
/// Poly: 0x07
/// Init: 0x00
/// Refin: false
/// Refout: false
/// Xorout: 0x00
///*************************************************************************
public static byte[] Crc7(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & 0x80) > )
crc = (byte)((crc << ) ^ 0x07);
else
crc = (byte)(crc << );
}
}
return new byte[] { crc };
}
/// **********************************************************************
/// Name: CRC-8/ITU x8+x2+x+1
/// Poly: 0x07
/// Init: 0x00
/// Refin: false
/// Refout: false
/// Xorout: 0x55
///*************************************************************************
public static byte[] Crc8(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & 0x80) > )
crc = (byte)((crc << ) ^ 0x07);
else
crc = (byte)(crc << );
}
}
return new byte[] { (byte)(crc ^ 0x55) };
}
/// **********************************************************************
/// Name: CRC-8/MAXIM x8+x5+x4+1
/// Poly: 0x31
/// Init: 0x00
/// Refin: true
/// Refout: true
/// Xorout: 0x00
///*************************************************************************
public static byte[] Crc9(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (byte)((crc >> ) ^ 0x8C);// 0x8C = reverse 0x31
else
crc = (byte)(crc >> );
}
}
return new byte[] { crc };
}
/// **********************************************************************
/// Name: CRC-8/ROHC x8+x2+x+1
/// Poly: 0x07
/// Init: 0xFF
/// Refin: true
/// Refout: true
/// Xorout: 0x00
///*************************************************************************
public static byte[] Crc10(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte crc = 0xFF;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (byte)((crc >> ) ^ 0xE0);// 0xE0 = reverse 0x07
else
crc = (byte)(crc >> );
}
}
return new byte[] { crc };
}
/// Z1协议校验码计算
static byte[] table = { 0x00, 0x1C, 0x38, 0x24, 0x70, 0x6C, 0x48, 0x54, 0xE0, 0xFC,
0xD8, 0xC4, 0x90, 0x8C, 0xA8, 0xB4, 0xDC, 0xC0, 0xE4, 0xF8,
0xAC, 0xB0, 0x94, 0x88, 0x3C, 0x20, 0x04, 0x18, 0x4C, 0x50,
0x74, 0x68, 0xA4, 0xB8, 0x9C, 0x80, 0xD4, 0xC8, 0xEC, 0xF0,
0x44, 0x58, 0x7C, 0x60, 0x34, 0x28, 0x0C, 0x10, 0x78, 0x64,
0x40, 0x5C, 0x08, 0x14, 0x30, 0x2C, 0x98, 0x84, 0xA0, 0xBC,
0xE8, 0xF4, 0xD0, 0xCC, 0x54, 0x48, 0x6C, 0x70, 0x24, 0x38,
0x1C, 0x00, 0xB4, 0xA8, 0x8C, 0x90, 0xC4, 0xD8, 0xFC, 0xE0,
0x88, 0x94, 0xB0, 0xAC, 0xF8, 0xE4, 0xC0, 0xDC, 0x68, 0x74,
0x50, 0x4C, 0x18, 0x04, 0x20, 0x3C, 0xF0, 0xEC, 0xC8, 0xD4,
0x80, 0x9C, 0xB8, 0xA4, 0x10, 0x0C, 0x28, 0x34, 0x60, 0x7C,
0x58, 0x44, 0x2C, 0x30, 0x14, 0x08, 0x5C, 0x40, 0x64, 0x78,
0xCC, 0xD0, 0xF4, 0xE8, 0xBC, 0xA0, 0x84, 0x98, 0xA8, 0xB4,
0x90, 0x8C, 0xD8, 0xC4, 0xE0, 0xFC, 0x48, 0x54, 0x70, 0x6C,
0x38, 0x24, 0x00, 0x1C, 0x74, 0x68, 0x4C, 0x50, 0x04, 0x18,
0x3C, 0x20, 0x94, 0x88, 0xAC, 0xB0, 0xE4, 0xF8, 0xDC, 0xC0,
0x0C, 0x10, 0x34, 0x28, 0x7C, 0x60, 0x44, 0x58, 0xEC, 0xF0,
0xD4, 0xC8, 0x9C, 0x80, 0xA4, 0xB8, 0xD0, 0xCC, 0xE8, 0xF4,
0xA0, 0xBC, 0x98, 0x84, 0x30, 0x2C, 0x08, 0x14, 0x40, 0x5C,
0x78, 0x64, 0xFC, 0xE0, 0xC4, 0xD8, 0x8C, 0x90, 0xB4, 0xA8,
0x1C, 0x00, 0x24, 0x38, 0x6C, 0x70, 0x54, 0x48, 0x20, 0x3C,
0x18, 0x04, 0x50, 0x4C, 0x68, 0x74, 0xC0, 0xDC, 0xF8, 0xE4,
0xB0, 0xAC, 0x88, 0x94, 0x58, 0x44, 0x60, 0x7C, 0x28, 0x34,
0x10, 0x0C, 0xB8, 0xA4, 0x80, 0x9C, 0xC8, 0xD4, 0xF0, 0xEC,
0x84, 0x98, 0xBC, 0xA0, 0xF4, 0xE8, 0xCC, 0xD0, 0x64, 0x78,
0x5C, 0x40, 0x14, 0x08, 0x2C, 0x30
};
public static byte[] Crc11(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
int i;
byte crc = 0x00;
int tableIndex;
for (i = start; i < length; i++)
{
tableIndex = crc ^ (buffer[i] & 0xFF);
crc = table[tableIndex];
}
return new byte[] { crc };
}
/// **********************************************************************
/// Name: CRC-12 x16+x12+x5+1
/// Poly: 0x80
/// Init: 0x0000
/// Refin: true
/// Refout: true
/// Xorout: 0x0000
///*************************************************************************
public static byte[] Crc12(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
ushort crc = ;// Initial value
short iQ = , iR = ;
for (int i = start; i < length; i++)
{
// 多项式除法
// 如果该位为1
if ((buffer[i] & (0x80 >> iR)) > )
{
// 则在余数尾部添1否则添0
crc |= 0x01;
}
// 如果12位除数中的最高位为1，则够除
if (crc >= 0x1000)
{
crc ^= 0x180D;
}
crc <<= ;
iR++;
if ( == iR)
{
iR = ;
iQ++;
}
}
// 对后面添加的12个0做处理
for (int i = ; i < ; i++)
{
if (crc >= 0x1000)
{
crc ^= 0x180D;
}
crc <<= ;
}
crc >>= ;
byte[] ret = BitConverter.GetBytes(crc);
Array.Reverse(ret);
return ret;
}
/// **********************************************************************
/// Name: CRC-16/CCITT x16+x12+x5+1
/// Poly: 0x1021
/// Init: 0x0000
/// Refin: true
/// Refout: true
/// Xorout: 0x0000
///*************************************************************************
public static byte[] Crc13(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
ushort crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (ushort)((crc >> ) ^ 0x8408);// 0x8408 = reverse 0x1021
else
crc = (ushort)(crc >> );
}
}
byte[] ret = BitConverter.GetBytes(crc);
Array.Reverse(ret);
return ret;
}
/// **********************************************************************
/// Name: CRC-16/CCITT FALSE x16+x12+x5+1
/// Poly: 0x1021
/// Init: 0xFFFF
/// Refin: false
/// Refout: false
/// Xorout: 0x0000
///*************************************************************************
public static byte[] Crc14(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
ushort crc = 0xFFFF;// Initial value
for (int i = start; i < length; i++)
{
crc ^= (ushort)(buffer[i] << );
for (int j = ; j < ; j++)
{
if ((crc & 0x8000) > )
crc = (ushort)((crc << ) ^ 0x1021);
else
crc = (ushort)(crc << );
}
}
byte[] ret = BitConverter.GetBytes(crc);
Array.Reverse(ret);
return ret;
}
/// **********************************************************************
/// Name: CRC-16/DNP x16+x13+x12+x11+x10+x8+x6+x5+x2+1
/// Poly: 0x3D65
/// Init: 0x0000
/// Refin: true
/// Refout: true
/// Xorout: 0xFFFF
///*************************************************************************
public static byte[] Crc15(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
ushort crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (ushort)((crc >> ) ^ 0xA6BC);// 0xA6BC = reverse 0x3D65
else
crc = (ushort)(crc >> );
}
}
byte[] ret = BitConverter.GetBytes((ushort)~crc);
Array.Reverse(ret);
return ret;
}
/// **********************************************************************
/// Name: CRC-16/IBM x16+x15+x2+1
/// Poly: 0x8005
/// Init: 0x0000
/// Refin: true
/// Refout: true
/// Xorout: 0x0000
///*************************************************************************
public static byte[] Crc16(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
ushort crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (ushort)((crc >> ) ^ 0xA001);// 0xA001 = reverse 0x8005
else
crc = (ushort)(crc >> );
}
}
byte[] ret = BitConverter.GetBytes(crc);
Array.Reverse(ret);
return ret;
}
/// **********************************************************************
/// Name: CRC-16/MAXIM x16+x15+x2+1
/// Poly: 0x8005
/// Init: 0x0000
/// Refin: true
/// Refout: true
/// Xorout: 0xFFFF
///*************************************************************************
public static byte[] Crc17(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
ushort crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (ushort)((crc >> ) ^ 0xA001);// 0xA001 = reverse 0x8005
else
crc = (ushort)(crc >> );
}
}
byte[] ret = BitConverter.GetBytes((ushort)~crc);
Array.Reverse(ret);
return ret;
}
/// **********************************************************************
/// Name: CRC-16/MODBUS x16+x15+x2+1
/// Poly: 0x8005
/// Init: 0xFFFF
/// Refin: true
/// Refout: true
/// Xorout: 0x0000
///*************************************************************************
public static byte[] Crc18(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
ushort crc = 0xFFFF;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (ushort)((crc >> ) ^ 0xA001);// 0xA001 = reverse 0x8005
else
crc = (ushort)(crc >> );
}
}
byte[] ret = BitConverter.GetBytes(crc);
Array.Reverse(ret);
return ret;
}
/// **********************************************************************
/// Name: CRC-16/USB x16+x15+x2+1
/// Poly: 0x8005
/// Init: 0xFFFF
/// Refin: true
/// Refout: true
/// Xorout: 0xFFFF
///*************************************************************************
public static byte[] Crc19(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
ushort crc = 0xFFFF;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (ushort)((crc >> ) ^ 0xA001);// 0xA001 = reverse 0x8005
else
crc = (ushort)(crc >> );
}
}
byte[] ret = BitConverter.GetBytes((ushort)~crc);
Array.Reverse(ret);
return ret;
}
/// **********************************************************************
/// Name: CRC-16/X25 x16+x12+x5+1
/// Poly: 0x1021
/// Init: 0xFFFF
/// Refin: true
/// Refout: true
/// Xorout: 0xFFFF
///*************************************************************************
public static byte[] Crc20(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
ushort crc = 0xFFFF;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (ushort)((crc >> ) ^ 0x8408);// 0x8408 = reverse 0x1021
else
crc = (ushort)(crc >> );
}
}
byte[] ret = BitConverter.GetBytes((ushort)~crc);
Array.Reverse(ret);
return ret;
}
/// **********************************************************************
/// Name: CRC-16/XMODEM x16+x12+x5+1
/// Poly: 0x1021
/// Init: 0x0000
/// Refin: false
/// Refout: false
/// Xorout: 0x0000
///*************************************************************************
public static byte[] Crc21(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
ushort crc = ;// Initial value
for (int i = start; i < length; i++)
{
crc ^= (ushort)(buffer[i] << );
for (int j = ; j < ; j++)
{
if ((crc & 0x8000) > )
crc = (ushort)((crc << ) ^ 0x1021);
else
crc = (ushort)(crc << );
}
}
byte[] ret = BitConverter.GetBytes(crc);
Array.Reverse(ret);
return ret;
}
/// **********************************************************************
/// Name: CRC32 x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x+1
/// Poly: 0x04C11DB7
/// Init: 0xFFFFFFFF
/// Refin: true
/// Refout: true
/// Xorout: 0xFFFFFFFF
///*************************************************************************
public static byte[] Crc22(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
uint crc = 0xFFFFFFFF;// Initial value
for (int i = start; i < length; i++)
{
crc ^= buffer[i];
for (int j = ; j < ; j++)
{
if ((crc & ) > )
crc = (crc >> ) ^ 0xEDB88320;// 0xEDB88320= reverse 0x04C11DB7
else
crc = crc >> ;
}
}
byte[] ret = BitConverter.GetBytes(~crc);
Array.Reverse(ret);
return ret;
}
/// **********************************************************************
/// Name: CRC32/MPEG-2 x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x+1
/// Poly: 0x04C11DB7
/// Init: 0xFFFFFFFF
/// Refin: false
/// Refout: false
/// Xorout: 0x00000000
///*************************************************************************
public static byte[] Crc23(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
uint crc = 0xFFFFFFFF;// Initial value
for (int i = start; i < length; i++)
{
crc ^= (uint)(buffer[i] << );
for (int j = ; j < ; j++)
{
if ((crc & 0x80000000) > )
crc = (crc << ) ^ 0x04C11DB7;
else
crc = crc << ;
}
}
byte[] ret = BitConverter.GetBytes(crc);
Array.Reverse(ret);
return ret;
}
纵向冗余校验（Longitudinal Redundancy Check，简称：LRC）是通信中常用的一种校验形式，也称LRC校验或纵向校验。 它是一种从纵向通道上的特定比特串产生校验比特的错误检测方法。在行列格式中（如磁带），LRC经常是与VRC一起使用，这样就会为每个字符校验码。在工业领域Modbus协议Ascii模式采用该算法。 LRC计算校验码,具体算法如下：
/// 1、对需要校验的数据（2n个字符）两两组成一个16进制的数值求和。
/// 2、将求和结果与256求模。
/// 3、用256减去所得模值得到校验结果（另一种方法：将模值按位取反然后加1）。
public static byte[] Lrc(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte lrc = ;// Initial value
for (int i = start; i < len; i++)
{
lrc += buffer[i];
}
lrc = (byte)((lrc ^ 0xFF) + );
return new byte[] { lrc };
}
BCC(Block Check Character/信息组校验码)，因校验码是将所有数据异或得出，故俗称异或校验。具体算法是：将每一个字节的数据（一般是两个16进制的字符）进行异或后即得到校验码。
public static byte[] Bcc(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte bcc = ;// Initial value
for (int i = start; i < len; i++)
{
bcc ^= buffer[i];
}
return new byte[] { bcc };
}
检验和(checksum)，在数据处理和数据通信领域中，用于校验目的地一组数据项的和。它通常是以十六进制为数制表示的形式。如果校验和的数值超过十六进制的FF,也就是255. 就要求其补码作为校验和。通常用来在通信中，尤其是远距离通信中保证数据的完整性和准确性。
public static byte[] allAdd(byte[] buffer, int start = , int len = )
{
if (buffer == null || buffer.Length == ) return null;
if (start < ) return null;
if (len == ) len = buffer.Length - start;
int length = start + len;
if (length > buffer.Length) return null;
byte bcc = ;// Initial value
for (int i = start; i < len; i++)
{
bcc ^= buffer[i];
}
return new byte[] { bcc };
}