CRC16-CCITT

CRC16-CCITT checksum algorithm. More...

Detailed Description

CRC16-CCITT checksum algorithm.

This implementation of CRC16 is based on the CCITT specification using 0x1D0F as a start value. Using a different start value is possible by calling crc16_ccitt_update() with the desired start value instead of crc16_ccitt_calc().

There is a more generalized version in CRC16 (lightweight), that does not utilize a look-up table as this implementation does (and is thus also for more memory efficient). Its caveat however is that it is slower by about factor 8 than this version.

Files
file	crc16_ccitt.h

Functions
uint16_t	crc16_ccitt_update (uint16_t crc, const unsigned char *buf, size_t len)
	Update CRC16-CCITT. More...
uint16_t	crc16_ccitt_calc (const unsigned char *buf, size_t len)
	Calculate CRC16-CCITT. More...

Function Documentation

crc16_ccitt_calc()

uint16_t crc16_ccitt_calc	(	const unsigned char *	buf,
		size_t	len
	)

Calculate CRC16-CCITT.

Parameters

[in]	buf	Start of the memory area to checksum
[in]	len	Number of bytes to checksum

Returns

Checksum of the specified memory area

crc16_ccitt_update()

uint16_t crc16_ccitt_update	(	uint16_t	crc,
		const unsigned char *	buf,
		size_t	len
	)

Update CRC16-CCITT.

Parameters

[in]	crc	A start value for the CRC calculation, usually the return value of a previous call to crc16_ccitt_calc() or crc16_ccitt_update()
[in]	buf	Start of the memory area to checksum
[in]	len	Number of bytes to checksum

Returns

Checksum of the specified memory area based on the given start value