CRC16常见的标准有以下几种，被用在各个规范中，其算法原理基本一致，就是在数据的输入和输出有所差异，下边把这些标准的差异列出，并给出C语言的算法实现。
CRC16_CCITT：多项式x16+x12+x5+1（0x1021），初始值0x0000，低位在前，高位在后，结果与0x0000异或
CRC16_CCITT_FALSE：多项式x16+x12+x5+1（0x1021），初始值0xFFFF，低位在后，高位在前，结果与0x0000异或
CRC16_XMODEM：多项式x16+x12+x5+1（0x1021），初始值0x0000，低位在后，高位在前，结果与0x0000异或
CRC16_X25：多项式x16+x12+x5+1（0x1021），初始值0x0000，低位在前，高位在后，结果与0xFFFF异或
CRC16_MODBUS：多项式x16+x15+x2+1（0x8005），初始值0xFFFF，低位在前，高位在后，结果与0x0000异或
CRC16_IBM：多项式x16+x15+x2+1（0x8005），初始值0x0000，低位在前，高位在后，结果与0x0000异或
CRC16_MAXIM：多项式x16+x15+x2+1（0x8005），初始值0x0000，低位在前，高位在后，结果与0xFFFF异或
CRC16_USB：多项式x16+x15+x2+1（0x8005），初始值0xFFFF，低位在前，高位在后，结果与0xFFFF异或
多项式产生：
如x16+x12+x5+1
x16表示第16位为1，x5表示第5位为1
(1 << 16) | (1 << 12) | (1 << 5) | (1) = 0x11021
但是CRC16只取低16位，写成16进制数就是 0x1021
CRC16的算法原理：
1.根据CRC16的标准选择初值CRCIn的值。
2.将数据的第一个字节与CRCIn高8位异或。
3.判断最高位，若该位为 0 左移一位，若为 1 左移一位再与多项式Hex码异或。
4.重复3直至8位全部移位计算结束。
5.重复将所有输入数据操作完成以上步骤，所得16位数即16位CRC校验码。
根据算法原理与标准要求就能简单的写出具体程序：
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。 Alias：别名及其应用范围。
/****************************Info********************************************** * Name: CRC-16/CCITT x16+x12+x5+1 * Width: 16 * Poly: 0x1021 * Init: 0x0000 * Refin: True * Refout: True * Xorout: 0x0000 * Alias: CRC-CCITT,CRC-16/CCITT-TRUE,CRC-16/KERMIT *****************************************************************************/ #if 0 unsigned short CRC16_CCITT(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0x0000; unsigned short wCPoly = 0x1021; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar << 8); for(int i = 0;i < 8;i++) { if(wCRCin & 0x8000) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } InvertUint16(&wCRCin,&wCRCin); return (wCRCin); } #else //这里为了效率，我们不需要将所有Refin和refout为true的输入输出数据移位转换 //只需要将poly二项式转换后，运算时将左移变为右移 unsigned short CRC16_CCITT(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0x0000; unsigned short wCPoly = 0x1021; unsigned char wChar = 0; InvertUint16(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ wCPoly; else wCRCin = wCRCin >> 1; } } return (wCRCin); } #endif /****************************Info********************************************** * Name: CRC-16/CCITT-FALSE x16+x12+x5+1 * Width: 16 * Poly: 0x1021 * Init: 0xFFFF * Refin: False * Refout: False * Xorout: 0x0000 * Note: *****************************************************************************/ unsigned short CRC16_CCITT_FALSE(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0xFFFF; unsigned short wCPoly = 0x1021; while (datalen--) { wCRCin ^= *(data++) << 8; for(int i = 0;i < 8;i++) { if(wCRCin & 0x8000) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } return (wCRCin); } /****************************Info********************************************** * Name: CRC-16/XMODEM x16+x12+x5+1 * Width: 16 * Poly: 0x1021 * Init: 0x0000 * Refin: False * Refout: False * Xorout: 0x0000 * Alias: CRC-16/ZMODEM,CRC-16/ACORN *****************************************************************************/ unsigned short CRC16_XMODEM(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0x0000; unsigned short wCPoly = 0x1021; while (datalen--) { wCRCin ^= (*(data++) << 8); for(int i = 0;i < 8;i++) { if(wCRCin & 0x8000) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } return (wCRCin); } /****************************Info********************************************** * Name: CRC-16/X25 x16+x12+x5+1 * Width: 16 * Poly: 0x1021 * Init: 0xFFFF * Refin: True * Refout: True * Xorout: 0XFFFF * Note: *****************************************************************************/ #if 0 unsigned short CRC16_X25(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0xFFFF; unsigned short wCPoly = 0x1021; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar << 8); for(int i = 0;i < 8;i++) { if(wCRCin & 0x8000) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } InvertUint16(&wCRCin,&wCRCin); return (wCRCin^0xFFFF); } #else unsigned short CRC16_X25(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0xFFFF; unsigned short wCPoly = 0x1021; InvertUint16(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ wCPoly; else wCRCin = wCRCin >> 1; } } return (wCRCin^0xFFFF); } #endif /****************************Info********************************************** * Name: CRC-16/MODBUS x16+x15+x2+1 * Width: 16 * Poly: 0x8005 * Init: 0xFFFF * Refin: True * Refout: True * Xorout: 0x0000 * Note: *****************************************************************************/ #if 0 unsigned short CRC16_MODBUS(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0xFFFF; unsigned short wCPoly = 0x8005; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar << 8); for(int i = 0;i < 8;i++) { if(wCRCin & 0x8000) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } InvertUint16(&wCRCin,&wCRCin); return (wCRCin); } #else unsigned short CRC16_MODBUS(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0xFFFF; unsigned short wCPoly = 0x8005; InvertUint16(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ wCPoly; else wCRCin = wCRCin >> 1; } } return (wCRCin); } #endif /****************************Info********************************************** * Name: CRC-16/IBM x16+x15+x2+1 * Width: 16 * Poly: 0x8005 * Init: 0x0000 * Refin: True * Refout: True * Xorout: 0x0000 * Alias: CRC-16,CRC-16/ARC,CRC-16/LHA *****************************************************************************/ #if 0 unsigned short CRC16_IBM(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0x0000; unsigned short wCPoly = 0x8005; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar << 8); for(int i = 0;i < 8;i++) { if(wCRCin & 0x8000) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } InvertUint16(&wCRCin,&wCRCin); return (wCRCin); } #else unsigned short CRC16_IBM(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0x0000; unsigned short wCPoly = 0x8005; InvertUint16(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ wCPoly; else wCRCin = wCRCin >> 1; } } return (wCRCin); } #endif /****************************Info********************************************** * Name: CRC-16/MAXIM x16+x15+x2+1 * Width: 16 * Poly: 0x8005 * Init: 0x0000 * Refin: True * Refout: True * Xorout: 0xFFFF * Note: *****************************************************************************/ #if 0 unsigned short CRC16_MAXIM(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0x0000; unsigned short wCPoly = 0x8005; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar << 8); for(int i = 0;i < 8;i++) { if(wCRCin & 0x8000) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } InvertUint16(&wCRCin,&wCRCin); return (wCRCin^0xFFFF); } #else unsigned short CRC16_MAXIM(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0x0000; unsigned short wCPoly = 0x8005; InvertUint16(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ wCPoly; else wCRCin = wCRCin >> 1; } } return (wCRCin^0xFFFF); } #endif /****************************Info********************************************** * Name: CRC-16/USB x16+x15+x2+1 * Width: 16 * Poly: 0x8005 * Init: 0xFFFF * Refin: True * Refout: True * Xorout: 0xFFFF * Note: *****************************************************************************/ #if 0 unsigned short CRC16_USB(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0xFFFF; unsigned short wCPoly = 0x8005; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar << 8); for(int i = 0;i < 8;i++) { if(wCRCin & 0x8000) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } InvertUint16(&wCRCin,&wCRCin); return (wCRCin^0xFFFF); } #else unsigned short CRC16_USB(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0xFFFF; unsigned short wCPoly = 0x8005; InvertUint16(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ wCPoly; else wCRCin = wCRCin >> 1; } } return (wCRCin^0xFFFF); } #endif /****************************Info********************************************** * Name: CRC-16/DNP x16+x13+x12+x11+x10+x8+x6+x5+x2+1 * Width: 16 * Poly: 0x3D65 * Init: 0x0000 * Refin: True * Refout: True * Xorout: 0xFFFF * Use: M-Bus,ect. *****************************************************************************/ #if 0 unsigned short CRC16_DNP(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0x0000; unsigned short wCPoly = 0x3D65; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar << 8); for(int i = 0;i < 8;i++) { if(wCRCin & 0x8000) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } InvertUint16(&wCRCin,&wCRCin); return (wCRCin^0xFFFF) ; } #else unsigned short CRC16_DNP(unsigned char *data, unsigned int datalen) { unsigned short wCRCin = 0x0000; unsigned short wCPoly = 0x3D65; InvertUint16(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ wCPoly; else wCRCin = (wCRCin >> 1); } } return (wCRCin^0xFFFF); } #endif
/****************************Info********************************************** * Name: InvertUint8 * Note: 把字节颠倒过来，如0x12变成0x48 0x12: 0001 0010 0x48: 0100 1000 *****************************************************************************/ void InvertUint8(unsigned char *dBuf,unsigned char *srcBuf) { int i; unsigned char tmp[4]={0}; for(i=0;i< 8;i++) { if(srcBuf[0]& (1 << i)) tmp[0]|=1<<(7-i); } dBuf[0] = tmp[0]; } void InvertUint16(unsigned short *dBuf,unsigned short *srcBuf) { int i; unsigned short tmp[4]={0}; for(i=0;i< 16;i++) { if(srcBuf[0]& (1 << i)) tmp[0]|=1<<(15 - i); } dBuf[0] = tmp[0]; } void InvertUint32(unsigned int *dBuf,unsigned int *srcBuf) { int i; unsigned int tmp[4]={0}; for(i=0;i< 32;i++) { if(srcBuf[0]& (1 << i)) tmp[0]|=1<<(31 - i); } dBuf[0] = tmp[0]; }
具体验证使用这个工具，内含CRC算法的计算，和后边的博客中提到的其他算法的工具合集
在这个基础上也加入CRC32 的校验算法
/****************************Info********************************************** * Name: CRC-32 x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x+1 * Width: 32 * Poly: 0x4C11DB7 * Init: 0xFFFFFFF * Refin: True * Refout: True * Xorout: 0xFFFFFFF * Alias: CRC_32/ADCCP * Use: WinRAR,ect. *****************************************************************************/ #if 0 unsigned int CRC32(unsigned char *data, unsigned int datalen) { unsigned int wCRCin = 0xFFFFFFFF; unsigned int wCPoly = 0x04C11DB7; unsigned int wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8((unsigned char *)&wChar,(unsigned char *)&wChar); wCRCin ^= (wChar << 24); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80000000) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } InvertUint32(&wCRCin,&wCRCin); return (wCRCin ^ 0xFFFFFFFF) ; } #else unsigned int CRC32(unsigned char *data, unsigned int datalen) { unsigned int wCRCin = 0xFFFFFFFF; unsigned int wCPoly = 0x04C11DB7; InvertUint32(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ wCPoly; else wCRCin = wCRCin >> 1; } } return (wCRCin ^ 0xFFFFFFFF) ; } #endif /****************************Info********************************************** * Name: CRC-32/MPEG-2 x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x+1 * Width: 32 * Poly: 0x4C11DB7 * Init: 0xFFFFFFF * Refin: False * Refout: False * Xorout: 0x0000000 * Note: *****************************************************************************/ unsigned int CRC32_MPEG(unsigned char *data, unsigned int datalen) { unsigned int wCRCin = 0xFFFFFFFF; unsigned int wCPoly = 0x04C11DB7; unsigned int wChar = 0; while (datalen--) { wChar = *(data++); wCRCin ^= (wChar << 24); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80000000) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } return (wCRCin) ; }
对于CRC32可能还有其他的多项式和初始值和结果值是否需要异或以及输入数据是否需要位序倒转等要求在源码中修改 本次在CRC算法的基础上加入CRC-4,5,6,7,8的各个算法实现：
/****************************Info********************************************** * Name: CRC-4/ITU x4+x+1 * Width: 4 * Poly: 0x03 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/ unsigned char CRC4_ITU(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x00; unsigned char wCPoly = 0x03; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80) wCRCin = (wCRCin << 1) ^ (wCPoly << 4); else wCRCin = wCRCin << 1; } } InvertUint8(&wCRCin,&wCRCin); return (wCRCin); } /****************************Info********************************************** * Name: CRC-5/EPC x5+x3+1 * Width: 5 * Poly: 0x09 * Init: 0x09 * Refin: False * Refout: False * Xorout: 0x00 * Note: *****************************************************************************/ unsigned char CRC5_EPC(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x09<<3; unsigned char wCPoly = 0x09<<3; while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80) wCRCin = (wCRCin << 1) ^ (wCPoly); else wCRCin = wCRCin << 1; } } return (wCRCin >> 3); } /****************************Info********************************************** * Name: CRC-5/USB x5+x2+1 * Width: 5 * Poly: 0x05 * Init: 0x1F * Refin: True * Refout: True * Xorout: 0x1F * Note: *****************************************************************************/ #if 0 unsigned char CRC5_USB(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x1F<<3; unsigned char wCPoly = 0x05; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80) wCRCin = (wCRCin << 1) ^ (wCPoly << 3); else wCRCin = wCRCin << 1; } } InvertUint8(&wCRCin,&wCRCin); return (wCRCin^0x1F); } #else unsigned char CRC5_USB(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x1F; unsigned char wCPoly = 0x05; InvertUint8(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ (wCPoly >> 3); else wCRCin = wCRCin >> 1; } } return (wCRCin^0x1F); } #endif /****************************Info********************************************** * Name: CRC-5/ITU x5+x4+x2+1 * Width: 5 * Poly: 0x15 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/ #if 0 unsigned char CRC5_ITU(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x00; unsigned char wCPoly = 0x15; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80) wCRCin = (wCRCin << 1) ^ (wCPoly << 3); else wCRCin = wCRCin << 1; } } InvertUint8(&wCRCin,&wCRCin); return (wCRCin); } #else unsigned char CRC5_ITU(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x00; unsigned char wCPoly = 0x15; InvertUint8(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ (wCPoly >> 3); else wCRCin = wCRCin >> 1; } } return (wCRCin); } #endif /****************************Info********************************************** * Name: CRC-6/ITU x6+x+1 * Width: 6 * Poly: 0x03 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/ unsigned char CRC6_ITU(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x00; unsigned char wCPoly = 0x03; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80) wCRCin = (wCRCin << 1) ^ (wCPoly << 2); else wCRCin = wCRCin << 1; } } InvertUint8(&wCRCin,&wCRCin); return (wCRCin); } /****************************Info********************************************** * Name: CRC-7/MMC x7+x3+1 * Width: 7 * Poly: 0x09 * Init: 0x00 * Refin: False * Refout: False * Xorout: 0x00 * Use: MultiMediaCard,SD,ect. *****************************************************************************/ unsigned char CRC7_MMC(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x00; unsigned char wCPoly = 0x09; while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80) wCRCin = (wCRCin << 1) ^ (wCPoly<<1); else wCRCin = wCRCin << 1; } } return (wCRCin>>1); } /****************************Info********************************************** * Name: CRC-8 x8+x2+x+1 * Width: 8 * Poly: 0x07 * Init: 0x00 * Refin: False * Refout: False * Xorout: 0x00 * Note: *****************************************************************************/ unsigned char CRC8(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x00; unsigned char wCPoly = 0x07; while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } return (wCRCin); } /****************************Info********************************************** * Name: CRC-8/ITU x8+x2+x+1 * Width: 8 * Poly: 0x07 * Init: 0x00 * Refin: False * Refout: False * Xorout: 0x55 * Alias: CRC-8/ATM *****************************************************************************/ unsigned char CRC8_ITU(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x00; unsigned char wCPoly = 0x07; while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } return (wCRCin^0x55); } /****************************Info********************************************** * Name: CRC-8/ROHC x8+x2+x+1 * Width: 8 * Poly: 0x07 * Init: 0xFF * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/ #if 0 unsigned char CRC8_ROHC(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0xFF; unsigned char wCPoly = 0x07; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar << 0); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } InvertUint8(&wCRCin,&wCRCin); return (wCRCin); } #else unsigned char CRC8_ROHC(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0xFF; unsigned char wCPoly = 0x07; InvertUint8(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ wCPoly; else wCRCin = wCRCin >> 1; } } return (wCRCin); } #endif /****************************Info********************************************** * Name: CRC-8/MAXIM x8+x5+x4+1 * Width: 8 * Poly: 0x31 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Alias: DOW-CRC,CRC-8/IBUTTON * Use: Maxim(Dallas)'s some devices,e.g. DS18B20 *****************************************************************************/ #if 0 unsigned char CRC8_MAXIM(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x00; unsigned char wCPoly = 0x31; unsigned char wChar = 0; while (datalen--) { wChar = *(data++); InvertUint8(&wChar,&wChar); wCRCin ^= (wChar << 0); for(int i = 0;i < 8;i++) { if(wCRCin & 0x80) wCRCin = (wCRCin << 1) ^ wCPoly; else wCRCin = wCRCin << 1; } } InvertUint8(&wCRCin,&wCRCin); return (wCRCin); } #else unsigned char CRC8_MAXIM(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x00; unsigned char wCPoly = 0x31; InvertUint8(&wCPoly,&wCPoly); while (datalen--) { wCRCin ^= *(data++); for(int i = 0;i < 8;i++) { if(wCRCin & 0x01) wCRCin = (wCRCin >> 1) ^ wCPoly; else wCRCin = wCRCin >> 1; } } return (wCRCin); } #endif
最后附上代码，里面含有测试程序
转:https://blog.csdn.net/leumber/article/details/54311811
/****************************Info********************************************** * Name: CRC-4/ITUx4+x+1 * Width:4 * Poly: 0x03 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/unsigned char CRC4_ITU(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0x00;unsigned char wCPoly = 0x03;unsigned char wChar = 0;while (datalen--) {wChar = *(data++);InvertUint8(&wChar,&wChar);wCRCin ^= (wChar);for(int i = 0;i < 8;i++){if(wCRCin & 0x80)wCRCin = (wCRCin << 1) ^ (wCPoly << 4);elsewCRCin = wCRCin << 1;}}InvertUint8(&wCRCin,&wCRCin);return (wCRCin);}/****************************Info********************************************** * Name: CRC-5/EPCx5+x3+1 * Width:5 * Poly: 0x09 * Init: 0x09 * Refin: False * Refout: False * Xorout: 0x00 * Note: *****************************************************************************/unsigned char CRC5_EPC(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0x09<<3;unsigned char wCPoly = 0x09<<3;while (datalen--) {wCRCin ^= *(data++);for(int i = 0;i < 8;i++){if(wCRCin & 0x80)wCRCin = (wCRCin << 1) ^ (wCPoly);elsewCRCin = wCRCin << 1;}}return (wCRCin >> 3);}/****************************Info********************************************** * Name: CRC-5/USBx5+x2+1 * Width:5 * Poly: 0x05 * Init: 0x1F * Refin: True * Refout: True * Xorout: 0x1F * Note: *****************************************************************************/#if 0unsigned char CRC5_USB(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0x1F<<3;unsigned char wCPoly = 0x05;unsigned char wChar = 0;while (datalen--) {wChar = *(data++);InvertUint8(&wChar,&wChar);wCRCin ^= (wChar);for(int i = 0;i < 8;i++){if(wCRCin & 0x80)wCRCin = (wCRCin << 1) ^ (wCPoly << 3);elsewCRCin = wCRCin << 1;}}InvertUint8(&wCRCin,&wCRCin);return (wCRCin^0x1F);}#elseunsigned char CRC5_USB(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x1F;unsigned char wCPoly = 0x05;InvertUint8(&wCPoly,&wCPoly);while (datalen--) {wCRCin ^= *(data++);for(int i = 0;i < 8;i++){if(wCRCin & 0x01)wCRCin = (wCRCin >> 1) ^ (wCPoly >> 3);elsewCRCin = wCRCin >> 1;}}return (wCRCin^0x1F); } #endif/****************************Info********************************************** * Name: CRC-5/ITUx5+x4+x2+1 * Width:5 * Poly: 0x15 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/ #if 0unsigned char CRC5_ITU(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0x00;unsigned char wCPoly = 0x15;unsigned char wChar = 0;while (datalen--) {wChar = *(data++);InvertUint8(&wChar,&wChar);wCRCin ^= (wChar);for(int i = 0;i < 8;i++){if(wCRCin & 0x80)wCRCin = (wCRCin << 1) ^ (wCPoly << 3);elsewCRCin = wCRCin << 1;}}InvertUint8(&wCRCin,&wCRCin);return (wCRCin);}#elseunsigned char CRC5_ITU(unsigned char *data, unsigned int datalen) { unsigned char wCRCin = 0x00;unsigned char wCPoly = 0x15;InvertUint8(&wCPoly,&wCPoly);while (datalen--) {wCRCin ^= *(data++);for(int i = 0;i < 8;i++){if(wCRCin & 0x01)wCRCin = (wCRCin >> 1) ^ (wCPoly >> 3);elsewCRCin = wCRCin >> 1;}}return (wCRCin); } #endif/****************************Info********************************************** * Name: CRC-6/ITUx6+x+1 * Width:6 * Poly: 0x03 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/unsigned char CRC6_ITU(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0x00;unsigned char wCPoly = 0x03;unsigned char wChar = 0;while (datalen--) {wChar = *(data++);InvertUint8(&wChar,&wChar);wCRCin ^= (wChar);for(int i = 0;i < 8;i++){if(wCRCin & 0x80)wCRCin = (wCRCin << 1) ^ (wCPoly << 2);elsewCRCin = wCRCin << 1;}}InvertUint8(&wCRCin,&wCRCin);return (wCRCin);}/****************************Info********************************************** * Name: CRC-7/MMC x7+x3+1 * Width:7 * Poly: 0x09 * Init: 0x00 * Refin: False * Refout: False * Xorout: 0x00 * Use: MultiMediaCard,SD,ect. *****************************************************************************/unsigned char CRC7_MMC(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0x00;unsigned char wCPoly = 0x09;while (datalen--) {wCRCin ^= *(data++);for(int i = 0;i < 8;i++){if(wCRCin & 0x80)wCRCin = (wCRCin << 1) ^ (wCPoly<<1);elsewCRCin = wCRCin << 1;}}return (wCRCin>>1);}/****************************Info********************************************** * Name: CRC-8 x8+x2+x+1 * Width:8 * Poly: 0x07 * Init: 0x00 * Refin: False * Refout: False * Xorout: 0x00 * Note: *****************************************************************************/unsigned char CRC8(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0x00;unsigned char wCPoly = 0x07;while (datalen--) {wCRCin ^= *(data++);for(int i = 0;i < 8;i++){if(wCRCin & 0x80)wCRCin = (wCRCin << 1) ^ wCPoly;elsewCRCin = wCRCin << 1;}}return (wCRCin);}/****************************Info********************************************** * Name: CRC-8/ITU x8+x2+x+1 * Width:8 * Poly: 0x07 * Init: 0x00 * Refin: False * Refout: False * Xorout: 0x55 * Alias: CRC-8/ATM *****************************************************************************/unsigned char CRC8_ITU(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0x00;unsigned char wCPoly = 0x07;while (datalen--) {wCRCin ^= *(data++);for(int i = 0;i < 8;i++){if(wCRCin & 0x80)wCRCin = (wCRCin << 1) ^ wCPoly;elsewCRCin = wCRCin << 1;}}return (wCRCin^0x55);}/****************************Info********************************************** * Name: CRC-8/ROHC x8+x2+x+1 * Width:8 * Poly: 0x07 * Init: 0xFF * Refin: True * Refout: True * Xorout: 0x00 * Note: *****************************************************************************/#if 0unsigned char CRC8_ROHC(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0xFF;unsigned char wCPoly = 0x07;unsigned char wChar = 0;while (datalen--) {wChar = *(data++);InvertUint8(&wChar,&wChar);wCRCin ^= (wChar << 0);for(int i = 0;i < 8;i++){if(wCRCin & 0x80)wCRCin = (wCRCin << 1) ^ wCPoly;elsewCRCin = wCRCin << 1;}}InvertUint8(&wCRCin,&wCRCin);return (wCRCin);}#else unsigned char CRC8_ROHC(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0xFF;unsigned char wCPoly = 0x07;InvertUint8(&wCPoly,&wCPoly);while (datalen--) {wCRCin ^= *(data++);for(int i = 0;i < 8;i++){if(wCRCin & 0x01)wCRCin = (wCRCin >> 1) ^ wCPoly;elsewCRCin = wCRCin >> 1;}}return (wCRCin);}#endif/****************************Info********************************************** * Name: CRC-8/MAXIM x8+x5+x4+1 * Width:8 * Poly: 0x31 * Init: 0x00 * Refin: True * Refout: True * Xorout: 0x00 * Alias: DOW-CRC,CRC-8/IBUTTON * Use: Maxim(Dallas)'s some devices,e.g. DS18B20 *****************************************************************************/ #if 0unsigned char CRC8_MAXIM(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0x00;unsigned char wCPoly = 0x31;unsigned char wChar = 0;while (datalen--) {wChar = *(data++);InvertUint8(&wChar,&wChar);wCRCin ^= (wChar << 0);for(int i = 0;i < 8;i++){if(wCRCin & 0x80)wCRCin = (wCRCin << 1) ^ wCPoly;elsewCRCin = wCRCin << 1;}}InvertUint8(&wCRCin,&wCRCin);return (wCRCin);}#else unsigned char CRC8_MAXIM(unsigned char *data, unsigned int datalen){unsigned char wCRCin = 0x00;unsigned char wCPoly = 0x31;InvertUint8(&wCPoly,&wCPoly);while (datalen--) {wCRCin ^= *(data++);for(int i = 0;i < 8;i++){if(wCRCin & 0x01)wCRCin = (wCRCin >> 1) ^ wCPoly;elsewCRCin = wCRCin >> 1;}}return (wCRCin);}#endif