crc16.h

这是一个非常有价值的参考代码

#ifndef CRC16_H
#define CRC16_H
/*
 * Derived from CRC algorithm for JTAG ICE mkII, published in Atmel
 * Appnote AVR067.  Converted from C++ to C.
 */

extern unsigned short crcsum(const unsigned char* message,
			     unsigned long length,
			     unsigned short crc);
/*
 * Verify that the last two bytes is a (LSB first) valid CRC of the
 * message.
 */
extern int crcverify(const unsigned char* message,
		     unsigned long length);
/*
 * Append a two byte CRC (LSB first) to message.  length is size of
 * message excluding crc.  Space for the CRC bytes must be allocated
 * in advance!
 */
extern void crcappend(unsigned char* message,
		      unsigned long length);

#endif