Variations of CRC16-CCITT checksum algorithms. More...

Detailed Description

Variations of CRC16-CCITT checksum algorithms.

This provides implementations for multiple variations of CRC16 checks.

There is a more generalized version in CRC16 (lightweight), that does not optionally utilize a look-up table as these implementations can do (and is thus also far more memory efficient). Its caveat however is that it is slower by about factor 8 than these versions when enabling the look-up table.

Note: enable the crc16_fast module for a look-up table based implementation that trades code size for speed.

Files
file	crc16_ccitt.h

Functions
uint16_t	crc16_ccitt_kermit_update (uint16_t crc, const unsigned char *buf, size_t len)
	Update CRC16-CCITT-KERMIT.

uint16_t	crc16_ccitt_kermit_calc (const unsigned char *buf, size_t len)
	Calculate CRC16-CCITT-KERMIT.

uint16_t	crc16_ccitt_fcs_start (const unsigned char *buf, size_t len)
	Start a CRC16-CCITT-FCS / IBM-SDLC calculation.

static uint16_t	crc16_ccitt_fcs_update (uint16_t crc, const unsigned char *buf, size_t len)
	Update CRC16-CCITT-FCS / IBM-SDLC.

uint16_t	crc16_ccitt_fcs_finish (uint16_t crc, const unsigned char *buf, size_t len)
	Finalise CRC16-CCITT-FCS / IBM-SDLC.

uint16_t	crc16_ccitt_fcs_calc (const unsigned char *buf, size_t len)
	Calculate CRC16-CCITT-FCS / IBM-SDLC in one pass.

static uint16_t	crc16_ccitt_mcrf4xx_update (uint16_t crc, const unsigned char *buf, size_t len)
	Update CRC16-CCITT-MCRF4XX.

uint16_t	crc16_ccitt_mcrf4xx_calc (const unsigned char *buf, size_t len)
	Calculate CRC16-CCITT-MCRF4XX.

uint16_t	crc16_ccitt_false_update (uint16_t crc, const unsigned char *buf, size_t len)
	Update CRC16-CCITT-FALSE.

uint16_t	crc16_ccitt_false_calc (const unsigned char *buf, size_t len)
	Calculate CRC16-CCITT-FALSE.

static uint16_t	crc16_ccitt_aug_update (uint16_t crc, const unsigned char *buf, size_t len)
	Update CRC16-CCITT-AUG.

uint16_t	crc16_ccitt_aug_calc (const unsigned char *buf, size_t len)
	Calculate CRC16-CCITT-AUG.

Function Documentation

◆ crc16_ccitt_aug_calc()

uint16_t crc16_ccitt_aug_calc	(	const unsigned char *	buf,
		size_t	len )

Calculate CRC16-CCITT-AUG.

Parameter	Value
Polynom	`0x1021`
Init	`0x1d0f`
Refin	`false`
Refout	`false`
Xorout	`0x0000`
Check	`0xe5cc`

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_aug_update()

static uint16_t crc16_ccitt_aug_update	(	uint16_t	crc,
		const unsigned char *	buf,
		size_t	len )

inlinestatic

Update CRC16-CCITT-AUG.

Parameters

[in]	crc	A start value for the CRC calculation, usually the return value of a previous call to crc16_ccitt_aug_calc() or crc16_ccitt_aug_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

Definition at line 223 of file crc16_ccitt.h.

◆ crc16_ccitt_false_calc()

uint16_t crc16_ccitt_false_calc	(	const unsigned char *	buf,
		size_t	len )

Calculate CRC16-CCITT-FALSE.

Parameter	Value
Polynom	`0x1021`
Init	`0xffff`
Refin	`false`
Refout	`false`
Xorout	`0x0000`
Check	`0x29b1`

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_false_update()

uint16_t crc16_ccitt_false_update	(	uint16_t	crc,
		const unsigned char *	buf,
		size_t	len )

Update CRC16-CCITT-FALSE.

Parameters

[in]	crc	A start value for the CRC calculation, usually the return value of a previous call to crc16_ccitt_false_calc() or crc16_ccitt_false_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

◆ crc16_ccitt_fcs_calc()

uint16_t crc16_ccitt_fcs_calc	(	const unsigned char *	buf,
		size_t	len )

Calculate CRC16-CCITT-FCS / IBM-SDLC in one pass.

Parameter	Value
Polynom	`0x1021`
Init	`0xffff`
Refin	`true`
Refout	`true`
Xorout	`0xffff`
Check	`0x906e`
Residue	`0xf0b8`

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_fcs_finish()

uint16_t crc16_ccitt_fcs_finish	(	uint16_t	crc,
		const unsigned char *	buf,
		size_t	len )

Finalise CRC16-CCITT-FCS / IBM-SDLC.

Parameters

[in]	crc	A start value for the CRC calculation, usually the return value of a previous call to crc16_ccitt_fcs_start() or crc16_ccitt_fcs_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.

◆ crc16_ccitt_fcs_start()

uint16_t crc16_ccitt_fcs_start	(	const unsigned char *	buf,
		size_t	len )

Start a CRC16-CCITT-FCS / IBM-SDLC calculation.

Parameters

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

Returns: Partial checksum of the specified memory area. To be finalised with crc16_ccitt_fcs_finish()

◆ crc16_ccitt_fcs_update()

static uint16_t crc16_ccitt_fcs_update	(	uint16_t	crc,
		const unsigned char *	buf,
		size_t	len )

inlinestatic

Update CRC16-CCITT-FCS / IBM-SDLC.

Parameters

[in]	crc	A start value for the CRC calculation, usually the return value of a previous call to crc16_ccitt_fcs_start() or crc16_ccitt_fcs_update()
[in]	buf	Start of the memory area to checksum
[in]	len	Number of bytes to checksum

Returns: Partial checksum of the specified memory area based on the given start value. To be finalised with crc16_ccitt_fcs_finish()

Definition at line 97 of file crc16_ccitt.h.

◆ crc16_ccitt_kermit_calc()

uint16_t crc16_ccitt_kermit_calc	(	const unsigned char *	buf,
		size_t	len )

Calculate CRC16-CCITT-KERMIT.

Parameter	Value
Polynom	`0x1021`
Init	`0x0000`
Refin	`true`
Refout	`true`
Xorout	`0x0000`
Check	`0x2189`

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_kermit_update()

uint16_t crc16_ccitt_kermit_update	(	uint16_t	crc,
		const unsigned char *	buf,
		size_t	len )

Update CRC16-CCITT-KERMIT.

Parameters

[in]	crc	A start value for the CRC calculation, usually the return value of a previous call to crc16_ccitt_kermit_calc() or crc16_ccitt_kermit_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

◆ crc16_ccitt_mcrf4xx_calc()

uint16_t crc16_ccitt_mcrf4xx_calc	(	const unsigned char *	buf,
		size_t	len )

Calculate CRC16-CCITT-MCRF4XX.

Parameter	Value
Polynom	`0x1021`
Init	`0xffff`
Refin	`true`
Refout	`true`
Xorout	`0x0000`
Check	`0x6f91`

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_mcrf4xx_update()

static uint16_t crc16_ccitt_mcrf4xx_update	(	uint16_t	crc,
		const unsigned char *	buf,
		size_t	len )

inlinestatic

Update CRC16-CCITT-MCRF4XX.

Parameters

[in]	crc	A start value for the CRC calculation, usually the return value of a previous call to crc16_ccitt_mcrf4xx_calc() or crc16_ccitt_mcrf4xx_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

Definition at line 151 of file crc16_ccitt.h.

Detailed Description

Files

Functions

Function Documentation

◆ crc16_ccitt_aug_calc()

◆ crc16_ccitt_aug_update()

◆ crc16_ccitt_false_calc()

◆ crc16_ccitt_false_update()

◆ crc16_ccitt_fcs_calc()

◆ crc16_ccitt_fcs_finish()

◆ crc16_ccitt_fcs_start()

◆ crc16_ccitt_fcs_update()

◆ crc16_ccitt_kermit_calc()

◆ crc16_ccitt_kermit_update()

◆ crc16_ccitt_mcrf4xx_calc()

◆ crc16_ccitt_mcrf4xx_update()