golang实现CRC8算法

CRC校验算法，就是把需要校验的数据与多项式进行循环异或（XOR），但进行异或的方式与实际中数据传输时，是高位先传、还是低位先传有关。对于数据高位先传的方式，异或从数据的高位开始，我们暂且称它顺序异或；对于数据低位先传的方式，异或从数据的低位开始，我们就叫它反序异或。

 

本文基于表达式x^8+x^5+x^4+x^0

一、顺序异或

  1.通过计算获取crc8

//x^8+x^5+x^4+x^0
func getcrc8High(buf []byte) (crc byte) {
	for  i := len(buf)-1 ; i   >=0  ; i--{
		crc ^= buf[i]
		for  j := 8 ; j > 0 ;j-- {
			if crc & 0x80 > 0 {
				crc = ( crc << 1 ) ^ 0x31
			}else {
				crc = crc << 1
			}
		}
	}

	return
}

  2.查表法

var crc8Table = []byte{
	0x00, 0x31, 0x62, 0x53, 0xc4, 0xf5, 0xa6, 0x97, 0xb9, 0x88, 0xdb, 0xea, 0x7d, 0x4c, 0x1f, 0x2e,
	0x43, 0x72, 0x21, 0x10, 0x87, 0xb6, 0xe5, 0xd4, 0xfa, 0xcb, 0x98, 0xa9, 0x3e, 0x0f, 0x5c, 0x6d,
	0x86, 0xb7, 0xe4, 0xd5, 0x42, 0x73, 0x20, 0x11, 0x3f, 0x0e, 0x5d, 0x6c, 0xfb, 0xca, 0x99, 0xa8,
	0xc5, 0xf4, 0xa7, 0x96, 0x01, 0x30, 0x63, 0x52, 0x7c, 0x4d, 0x1e, 0x2f, 0xb8, 0x89, 0xda, 0xeb,
	0x3d, 0x0c, 0x5f, 0x6e, 0xf9, 0xc8, 0x9b, 0xaa, 0x84, 0xb5, 0xe6, 0xd7, 0x40, 0x71, 0x22, 0x13,
	0x7e, 0x4f, 0x1c, 0x2d, 0xba, 0x8b, 0xd8, 0xe9, 0xc7, 0xf6, 0xa5, 0x94, 0x03, 0x32, 0x61, 0x50,
	0xbb, 0x8a, 0xd9, 0xe8, 0x7f, 0x4e, 0x1d, 0x2c, 0x02, 0x33, 0x60, 0x51, 0xc6, 0xf7, 0xa4, 0x95,
	0xf8, 0xc9, 0x9a, 0xab, 0x3c, 0x0d, 0x5e, 0x6f, 0x41, 0x70, 0x23, 0x12, 0x85, 0xb4, 0xe7, 0xd6,
	0x7a, 0x4b, 0x18, 0x29, 0xbe, 0x8f, 0xdc, 0xed, 0xc3, 0xf2, 0xa1, 0x90, 0x07, 0x36, 0x65, 0x54,
	0x39, 0x08, 0x5b, 0x6a, 0xfd, 0xcc, 0x9f, 0xae, 0x80, 0xb1, 0xe2, 0xd3, 0x44, 0x75, 0x26, 0x17,
	0xfc, 0xcd, 0x9e, 0xaf, 0x38, 0x09, 0x5a, 0x6b, 0x45, 0x74, 0x27, 0x16, 0x81, 0xb0, 0xe3, 0xd2,
	0xbf, 0x8e, 0xdd, 0xec, 0x7b, 0x4a, 0x19, 0x28, 0x06, 0x37, 0x64, 0x55, 0xc2, 0xf3, 0xa0, 0x91,
	0x47, 0x76, 0x25, 0x14, 0x83, 0xb2, 0xe1, 0xd0, 0xfe, 0xcf, 0x9c, 0xad, 0x3a, 0x0b, 0x58, 0x69,
	0x04, 0x35, 0x66, 0x57, 0xc0, 0xf1, 0xa2, 0x93, 0xbd, 0x8c, 0xdf, 0xee, 0x79, 0x48, 0x1b, 0x2a,
	0xc1, 0xf0, 0xa3, 0x92, 0x05, 0x34, 0x67, 0x56, 0x78, 0x49, 0x1a, 0x2b, 0xbc, 0x8d, 0xde, 0xef,
	0x82, 0xb3, 0xe0, 0xd1, 0x46, 0x77, 0x24, 0x15, 0x3b, 0x0a, 0x59, 0x68, 0xff, 0xce, 0x9d, 0xac,
}


func getCRC8HighByTable(buf []byte) (val byte) {
	for  i := len(buf)-1 ; i  >= 0 ; i-- {
		val = crc8Table[(val^buf[i])&0xff]
	}
	return
}

   

二、反序异或

1.通过计算获取crc8

//x^8+x^5+x^4+x^0
func getcrc8(buf []byte) (crc byte) {
	for  i := 0 ; i   < len(buf)  ; i++ {
		crc ^= buf[i]
		for  j := 8 ; j > 0 ;j-- {
			if crc & 0x01 > 0 {
				crc = ( crc >> 1 ) ^ 0x8c
			}else {
				crc = crc >> 1
			}
		}
	}

	return
}

2. 查表法

  

//x^8+x^5+x^4+x^0
func getcrc8ByTable(buf []byte) (crc byte) {
	for  i := 0 ; i < len(buf) ; i++ {
		crc = crcTableMax[(crc^buf[i])&0xff]
	}
	return
}



var crcTableMax = []byte{
	0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,
	157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,
	35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98,
	190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255,
	70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7,
	219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154,
	101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36,
	248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185,
	140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205,
	17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80,
	175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238,
	50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115,
	202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139,
	87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22,
	233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168,
	116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53,
}