Cyclic Redundancy Check 16 (CRC16) calculation

The Cyclic Redundancy Check 16 is a hash function that produces a checksum that is used to detect errors in transmissions.

The CRC16 calculation module is an iterative CRC calculator that can be used to cumulatively update a CRC checksum for every incoming byte.

Files
file	crc16.c
	Implementation of the CRC16 calculcation
file	crc16.h
	Header file for the CRC16 calculcation

Functions
unsigned short	crc16_add (unsigned char b, unsigned short crc)
	Update an accumulated CRC16 checksum with one byte. More...
unsigned short	crc16_data (const unsigned char *data, int datalen, unsigned short acc)
	Calculate the CRC16 over a data area. More...

unsigned short crc16_add	(	unsigned char	b,
		unsigned short	crc
	)

Update an accumulated CRC16 checksum with one byte.

Parameters

b	The byte to be added to the checksum
crc	The accumulated CRC that is to be updated.

Returns

The updated CRC checksum.

        This function updates an accumulated CRC16 checksum
        with one byte. It can be used as a running checksum, or
        to checksum an entire data block.

        \note The algorithm used in this implementation is
        tailored for a running checksum and does not perform as
        well as a table-driven algorithm when checksumming an
        entire data block.

Referenced by crc16_data().

unsigned short crc16_data	(	const unsigned char *	data,
		int	datalen,
		unsigned short	acc
	)

Calculate the CRC16 over a data area.

Parameters

data	Pointer to the data
datalen	The length of the data
crc	The accumulated CRC that is to be updated (or zero).

Returns

The CRC16 checksum.

        This function calculates the CRC16 checksum of a data area.

        \note The algorithm used in this implementation is
        tailored for a running checksum and does not perform as
        well as a table-driven algorithm when checksumming an
        entire data block.

References crc16_add(), data, i, and len.