Functions
uint16_t	crc16 (const uint8_t *src, size_t len, uint16_t polynomial, uint16_t initial_value, bool pad)
	Generic function for computing CRC 16. More...

uint8_t	crc8 (const uint8_t *src, size_t len, uint8_t polynomial, uint8_t initial_value, bool reversed)
	Generic function for computing CRC 8. More...

uint16_t	crc16_ccitt (uint16_t seed, const uint8_t *src, size_t len)
	Compute the CRC-16/CCITT checksum of a buffer. More...

uint16_t	crc16_itu_t (uint16_t seed, const uint8_t *src, size_t len)
	Compute the CRC-16/XMODEM checksum of a buffer. More...

static uint16_t	crc16_ansi (const uint8_t *src, size_t len)
	Compute ANSI variant of CRC 16. More...

uint32_t	crc32_ieee (const uint8_t *data, size_t len)
	Generate IEEE conform CRC32 checksum. More...

uint32_t	crc32_ieee_update (uint32_t crc, const uint8_t *data, size_t len)
	Update an IEEE conforming CRC32 checksum. More...

uint32_t	crc32_c (uint32_t crc, const uint8_t *data, size_t len, bool first_pkt, bool last_pkt)
	Calculate CRC32C (Castagnoli) checksum. More...

uint8_t	crc8_ccitt (uint8_t initial_value, const void *buf, size_t len)
	Compute CCITT variant of CRC 8. More...

uint8_t	crc7_be (uint8_t seed, const uint8_t *src, size_t len)
	Compute the CRC-7 checksum of a buffer. More...

Detailed Description

Function Documentation

◆ crc16()

uint16_t crc16	(	const uint8_t *	src,
		size_t	len,
		uint16_t	polynomial,
		uint16_t	initial_value,
		bool	pad
	)

#include <include/sys/crc.h>

Generic function for computing CRC 16.

Compute CRC 16 by passing in the address of the input, the input length and polynomial used in addition to the initial value.

Parameters

src	Input bytes for the computation
len	Length of the input in bytes
polynomial	The polynomial to use omitting the leading x^16 coefficient
initial_value	Initial value for the CRC computation
pad	Adds padding with zeros at the end of input bytes

Returns: The computed CRC16 value

◆ crc16_ansi()

static uint16_t crc16_ansi	(	const uint8_t *	src,
		size_t	len
	)

inlinestatic

#include <include/sys/crc.h>

Compute ANSI variant of CRC 16.

ANSI variant of CRC 16 is using 0x8005 as its polynomial with the initial value set to 0xffff.

Parameters

src	Input bytes for the computation
len	Length of the input in bytes

Returns: The computed CRC16 value

◆ crc16_ccitt()

uint16_t crc16_ccitt	(	uint16_t	seed,
		const uint8_t *	src,
		size_t	len
	)

#include <include/sys/crc.h>

Compute the CRC-16/CCITT checksum of a buffer.

See ITU-T Recommendation V.41 (November 1988). Uses 0x1021 as the polynomial, reflects the input, and reflects the output.

To calculate the CRC across non-contiguous blocks use the return value from block N-1 as the seed for block N.

For CRC-16/CCITT, use 0 as the initial seed. Other checksums in the same family can be calculated by changing the seed and/or XORing the final value. Examples include:

X-25 (used in PPP): seed=0xffff, xor=0xffff, residual=0xf0b8

Note: API changed in Zephyr 1.11.

Parameters

seed	Value to seed the CRC with
src	Input bytes for the computation
len	Length of the input in bytes

Returns: The computed CRC16 value

◆ crc16_itu_t()

uint16_t crc16_itu_t	(	uint16_t	seed,
		const uint8_t *	src,
		size_t	len
	)

#include <include/sys/crc.h>

Compute the CRC-16/XMODEM checksum of a buffer.

The MSB first version of ITU-T Recommendation V.41 (November 1988). Uses 0x1021 as the polynomial with no reflection.

To calculate the CRC across non-contiguous blocks use the return value from block N-1 as the seed for block N.

For CRC-16/XMODEM, use 0 as the initial seed. Other checksums in the same family can be calculated by changing the seed and/or XORing the final value. Examples include:

CCIITT-FALSE: seed=0xffff
GSM: seed=0, xorout=0xffff, residue=0x1d0f

Parameters

seed	Value to seed the CRC with
src	Input bytes for the computation
len	Length of the input in bytes

Returns: The computed CRC16 value

◆ crc32_c()

uint32_t crc32_c	(	uint32_t	crc,
		const uint8_t *	data,
		size_t	len,
		bool	first_pkt,
		bool	last_pkt
	)

#include <include/sys/crc.h>

Calculate CRC32C (Castagnoli) checksum.

Parameters

crc	CRC32C checksum that needs to be updated.
*data	Pointer to data on which the CRC should be calculated.
len	Data length.
first_pkt	Whether this is the first packet in the stream.
last_pkt	Whether this is the last packet in the stream.

Returns: CRC32 value.

◆ crc32_ieee()

uint32_t crc32_ieee	(	const uint8_t *	data,
		size_t	len
	)

#include <include/sys/crc.h>

Generate IEEE conform CRC32 checksum.

Parameters

*data	Pointer to data on which the CRC should be calculated.
len	Data length.

Returns: CRC32 value.

◆ crc32_ieee_update()

uint32_t crc32_ieee_update	(	uint32_t	crc,
		const uint8_t *	data,
		size_t	len
	)

#include <include/sys/crc.h>

Update an IEEE conforming CRC32 checksum.

Parameters

crc	CRC32 checksum that needs to be updated.
*data	Pointer to data on which the CRC should be calculated.
len	Data length.

Returns: CRC32 value.

◆ crc7_be()

uint8_t crc7_be	(	uint8_t	seed,
		const uint8_t *	src,
		size_t	len
	)

#include <include/sys/crc.h>

Compute the CRC-7 checksum of a buffer.

See JESD84-A441. Used by the MMC protocol. Uses 0x09 as the polynomial with no reflection. The CRC is left justified, so bit 7 of the result is bit 6 of the CRC.

Parameters

seed	Value to seed the CRC with
src	Input bytes for the computation
len	Length of the input in bytes

Returns: The computed CRC7 value

◆ crc8()

uint8_t crc8	(	const uint8_t *	src,
		size_t	len,
		uint8_t	polynomial,
		uint8_t	initial_value,
		bool	reversed
	)

#include <include/sys/crc.h>

Generic function for computing CRC 8.

Compute CRC 8 by passing in the address of the input, the input length and polynomial used in addition to the initial value.

Parameters

src	Input bytes for the computation
len	Length of the input in bytes
polynomial	The polynomial to use omitting the leading x^8 coefficient
initial_value	Initial value for the CRC computation
reversed	Should we use reflected/reversed values or not

Returns: The computed CRC8 value

◆ crc8_ccitt()

uint8_t crc8_ccitt	(	uint8_t	initial_value,
		const void *	buf,
		size_t	len
	)

#include <include/sys/crc.h>

Compute CCITT variant of CRC 8.

Normal CCITT variant of CRC 8 is using 0x07.

Parameters

initial_value	Initial value for the CRC computation
buf	Input bytes for the computation
len	Length of the input in bytes

Returns: The computed CRC8 value

Functions

Detailed Description

Function Documentation

◆ crc16()

◆ crc16_ansi()

◆ crc16_ccitt()

◆ crc16_itu_t()

◆ crc32_c()

◆ crc32_ieee()

◆ crc32_ieee_update()

◆ crc7_be()

◆ crc8()

◆ crc8_ccitt()