分类： C/C++
2009-08-21 13:39:22
查表法：(生成多项式X^8+X^6+X^4+X^3+X^2+X^1)
const uchar crctable[] = {
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};
UCHAR CRC8（UCHAR IN，UCHAR CRC）
{
IN^= crc;
crc = crctable[IN];
RETURN crc ；
}
VOID MAIN （VOID）
{
CRC=0；
FOR（I=0；I<100;I++）
CRC=CRC8（TABLE[I],CRC）;
}
算法：
UCHAR CRC8（UCHAR IN，UCHAR CRC）
{
uchar i,crc;
for (i=0;i<8;i )
{
if ((IN&1)^(crc&0x80)==0) {crc<<=1;} /* 做(1),(2); (1)=0,则CRC向高位移1位. */
else
{
crc=crc^0x18; /* (1)=1,则异或18 */
crc<<=1;
crc|=1; /* 置CRC.0为1 */
}
IN>>=1;
}
}
备注：在数据传输中CRC或传过来的数据，可能低字节在前，高字节在后，这就造成查表法表中被查数据不同。
