Static class for computing CRCs. More...

#include <crc.h>

Classes
struct	Parameters
	CRC parameters. More...

struct	Table
	CRC lookup table. After construction, the CRC parameters are fixed. More...

Static Public Member Functions
template<typename CRCType , crcpp_uint16 CRCWidth>
static CRCType	Calculate (const void *data, crcpp_size size, const Parameters< CRCType, CRCWidth > &parameters)
	Computes a CRC. More...

template<typename CRCType , crcpp_uint16 CRCWidth>
static CRCType	Calculate (const void *data, crcpp_size size, const Parameters< CRCType, CRCWidth > &parameters, CRCType crc)
	Appends additional data to a previous CRC calculation. More...

template<typename CRCType , crcpp_uint16 CRCWidth>
static CRCType	Calculate (const void *data, crcpp_size size, const Table< CRCType, CRCWidth > &lookupTable)
	Computes a CRC via a lookup table. More...

template<typename CRCType , crcpp_uint16 CRCWidth>
static CRCType	Calculate (const void *data, crcpp_size size, const Table< CRCType, CRCWidth > &lookupTable, CRCType crc)
	Appends additional data to a previous CRC calculation using a lookup table. More...

static const Parameters< crcpp_uint16, 16 > &	CRC_16_ARC ()
	Returns a set of parameters for CRC-16 ARC (aka CRC-16 IBM, CRC-16 LHA). More...

static const Parameters< crcpp_uint16, 16 > &	CRC_16_BUYPASS ()
	Returns a set of parameters for CRC-16 BUYPASS (aka CRC-16 VERIFONE, CRC-16 UMTS). More...

static const Parameters< crcpp_uint16, 16 > &	CRC_16_CCITTFALSE ()
	Returns a set of parameters for CRC-16 CCITT FALSE. More...

static const Parameters< crcpp_uint16, 16 > &	CRC_16_GENIBUS ()
	Returns a set of parameters for CRC-16 GENIBUS (aka CRC-16 EPC, CRC-16 I-CODE, CRC-16 DARC). More...

static const Parameters< crcpp_uint16, 16 > &	CRC_16_KERMIT ()
	Returns a set of parameters for CRC-16 KERMIT (aka CRC-16 CCITT, CRC-16 CCITT-TRUE). More...

static const Parameters< crcpp_uint16, 16 > &	CRC_16_X25 ()
	Returns a set of parameters for CRC-16 X-25 (aka CRC-16 IBM-SDLC, CRC-16 ISO-HDLC, CRC-16 B). More...

static const Parameters< crcpp_uint16, 16 > &	CRC_16_XMODEM ()
	Returns a set of parameters for CRC-16 XMODEM (aka CRC-16 ZMODEM, CRC-16 ACORN, CRC-16 LTE). More...

static const Parameters< crcpp_uint32, 32 > &	CRC_32 ()
	Returns a set of parameters for CRC-32 (aka CRC-32 ADCCP, CRC-32 PKZip). More...

static const Parameters< crcpp_uint32, 32 > &	CRC_32_BZIP2 ()
	Returns a set of parameters for CRC-32 BZIP2 (aka CRC-32 AAL5, CRC-32 DECT-B, CRC-32 B-CRC). More...

static const Parameters< crcpp_uint32, 32 > &	CRC_32_MPEG2 ()
	Returns a set of parameters for CRC-32 MPEG-2. More...

static const Parameters< crcpp_uint32, 32 > &	CRC_32_POSIX ()
	Returns a set of parameters for CRC-32 POSIX. More...

static const Parameters< crcpp_uint8, 8 > &	CRC_8 ()
	Returns a set of parameters for CRC-8 SMBus. More...

Private Member Functions
	CRC ()

	CRC (const CRC &other)

CRC &	operator= (const CRC &other)

Static Private Member Functions
template<typename CRCType , crcpp_uint16 CRCWidth>
static CRCType	CalculateRemainder (const void *data, crcpp_size size, const Parameters< CRCType, CRCWidth > &parameters, CRCType remainder)
	Computes a CRC remainder. More...

template<typename CRCType , crcpp_uint16 CRCWidth>
static CRCType	CalculateRemainder (const void *data, crcpp_size size, const Table< CRCType, CRCWidth > &lookupTable, CRCType remainder)
	Computes a CRC remainder using lookup table. More...

template<typename CRCType , crcpp_uint16 CRCWidth>
static CRCType	Finalize (CRCType remainder, CRCType finalXOR, bool reflectOutput)
	Computes the final reflection and XOR of a CRC remainder. More...

template<typename IntegerType >
static IntegerType	Reflect (IntegerType value, crcpp_uint16 numBits)
	Reflects (i.e. reverses the bits within) an integer value. More...

template<typename CRCType , crcpp_uint16 CRCWidth>
static CRCType	UndoFinalize (CRCType remainder, CRCType finalXOR, bool reflectOutput)
	Undoes the process of computing the final reflection and XOR of a CRC remainder. More...

Detailed Description

Static class for computing CRCs.

Note: This class supports computation of full and multi-part CRCs, using a bit-by-bit algorithm or a byte-by-byte lookup table. The CRCs are calculated using as many optimizations as is reasonable. If compiling with C++11, the constexpr keyword is used liberally so that many calculations are performed at compile-time instead of at runtime.

Definition at line 142 of file crc.h.

Constructor & Destructor Documentation

CRC::CRC ( )

private

CRC::CRC ( const CRC & other )

private

Member Function Documentation

template<typename CRCType , crcpp_uint16 CRCWidth>

CRCType CRC::Calculate	(	const void *	data,
		crcpp_size	size,
		const Parameters< CRCType, CRCWidth > &	parameters
	)

inlinestatic

Computes a CRC.

Parameters

[in]	data	Data over which CRC will be computed
[in]	size	Size of the data
[in]	parameters	CRC parameters

Template Parameters

CRCType	Integer type for storing the CRC result
CRCWidth	Number of bits in the CRC

Returns: CRC

Definition at line 434 of file crc.h.

template<typename CRCType , crcpp_uint16 CRCWidth>

CRCType CRC::Calculate	(	const void *	data,
		crcpp_size	size,
		const Parameters< CRCType, CRCWidth > &	parameters,
		CRCType	crc
	)

inlinestatic

Appends additional data to a previous CRC calculation.

Note: This function can be used to compute multi-part CRCs.

Parameters

[in]	data	Data over which CRC will be computed
[in]	size	Size of the data
[in]	parameters	CRC parameters
[in]	crc	CRC from a previous calculation

Template Parameters

CRCType	Integer type for storing the CRC result
CRCWidth	Number of bits in the CRC

Returns: CRC

Definition at line 454 of file crc.h.

template<typename CRCType , crcpp_uint16 CRCWidth>

CRCType CRC::Calculate	(	const void *	data,
		crcpp_size	size,
		const Table< CRCType, CRCWidth > &	lookupTable
	)

inlinestatic

Computes a CRC via a lookup table.

Parameters

[in]	data	Data over which CRC will be computed
[in]	size	Size of the data
[in]	lookupTable	CRC lookup table

Template Parameters

CRCType	Integer type for storing the CRC result
CRCWidth	Number of bits in the CRC

Returns: CRC

Definition at line 475 of file crc.h.

template<typename CRCType , crcpp_uint16 CRCWidth>

CRCType CRC::Calculate	(	const void *	data,
		crcpp_size	size,
		const Table< CRCType, CRCWidth > &	lookupTable,
		CRCType	crc
	)

inlinestatic

Appends additional data to a previous CRC calculation using a lookup table.

Note: This function can be used to compute multi-part CRCs.

Parameters

[in]	data	Data over which CRC will be computed
[in]	size	Size of the data
[in]	lookupTable	CRC lookup table
[in]	crc	CRC from a previous calculation

Template Parameters

CRCType	Integer type for storing the CRC result
CRCWidth	Number of bits in the CRC

Returns: CRC

Definition at line 498 of file crc.h.

template<typename CRCType , crcpp_uint16 CRCWidth>

CRCType CRC::CalculateRemainder	(	const void *	data,
		crcpp_size	size,
		const Parameters< CRCType, CRCWidth > &	parameters,
		CRCType	remainder
	)

inlinestaticprivate

Computes a CRC remainder.

Parameters

[in]	data	Data over which the remainder will be computed
[in]	size	Size of the data
[in]	parameters	CRC parameters
[in]	remainder	Running CRC remainder. Can be an initial value or the result of a previous CRC remainder calculation.

Template Parameters

CRCType	Integer type for storing the CRC result
CRCWidth	Number of bits in the CRC

Returns: CRC remainder

Definition at line 601 of file crc.h.

template<typename CRCType , crcpp_uint16 CRCWidth>

CRCType CRC::CalculateRemainder	(	const void *	data,
		crcpp_size	size,
		const Table< CRCType, CRCWidth > &	lookupTable,
		CRCType	remainder
	)

inlinestaticprivate

Computes a CRC remainder using lookup table.

Parameters

[in]	data	Data over which the remainder will be computed
[in]	size	Size of the data
[in]	lookupTable	CRC lookup table
[in]	remainder	Running CRC remainder. Can be an initial value or the result of a previous CRC remainder calculation.

Template Parameters

CRCType	Integer type for storing the CRC result
CRCWidth	Number of bits in the CRC

Returns: CRC remainder

Definition at line 718 of file crc.h.

const CRC::Parameters< crcpp_uint16, 16 > & CRC::CRC_16_ARC ( )

inlinestatic

Returns a set of parameters for CRC-16 ARC (aka CRC-16 IBM, CRC-16 LHA).

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-16 ARC has the following parameters and check value:

polynomial = 0x8005
initial value = 0x0000
final XOR = 0x0000
reflect input = true
reflect output = true
check value = 0xBB3D

Returns: CRC-16 ARC parameters

Definition at line 1162 of file crc.h.

const CRC::Parameters< crcpp_uint16, 16 > & CRC::CRC_16_BUYPASS ( )

inlinestatic

Returns a set of parameters for CRC-16 BUYPASS (aka CRC-16 VERIFONE, CRC-16 UMTS).

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-16 BUYPASS has the following parameters and check value:

polynomial = 0x8005
initial value = 0x0000
final XOR = 0x0000
reflect input = false
reflect output = false
check value = 0xFEE8

Returns: CRC-16 BUYPASS parameters

Definition at line 1180 of file crc.h.

const CRC::Parameters< crcpp_uint16, 16 > & CRC::CRC_16_CCITTFALSE ( )

inlinestatic

Returns a set of parameters for CRC-16 CCITT FALSE.

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-16 CCITT FALSE has the following parameters and check value:

polynomial = 0x1021
initial value = 0xFFFF
final XOR = 0x0000
reflect input = false
reflect output = false
check value = 0x29B1

Returns: CRC-16 CCITT FALSE parameters

Definition at line 1198 of file crc.h.

const CRC::Parameters< crcpp_uint16, 16 > & CRC::CRC_16_GENIBUS ( )

inlinestatic

Returns a set of parameters for CRC-16 GENIBUS (aka CRC-16 EPC, CRC-16 I-CODE, CRC-16 DARC).

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-16 GENIBUS has the following parameters and check value:

polynomial = 0x1021
initial value = 0xFFFF
final XOR = 0xFFFF
reflect input = false
reflect output = false
check value = 0xD64E

Returns: CRC-16 GENIBUS parameters

Definition at line 1308 of file crc.h.

const CRC::Parameters< crcpp_uint16, 16 > & CRC::CRC_16_KERMIT ( )

inlinestatic

Returns a set of parameters for CRC-16 KERMIT (aka CRC-16 CCITT, CRC-16 CCITT-TRUE).

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-16 KERMIT has the following parameters and check value:

polynomial = 0x1021
initial value = 0x0000
final XOR = 0x0000
reflect input = true
reflect output = true
check value = 0x2189

Returns: CRC-16 KERMIT parameters

Definition at line 1326 of file crc.h.

const CRC::Parameters< crcpp_uint16, 16 > & CRC::CRC_16_X25 ( )

inlinestatic

Returns a set of parameters for CRC-16 X-25 (aka CRC-16 IBM-SDLC, CRC-16 ISO-HDLC, CRC-16 B).

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-16 X-25 has the following parameters and check value:

polynomial = 0x1021
initial value = 0xFFFF
final XOR = 0xFFFF
reflect input = true
reflect output = true
check value = 0x906E

Returns: CRC-16 X-25 parameters

Definition at line 1419 of file crc.h.

const CRC::Parameters< crcpp_uint16, 16 > & CRC::CRC_16_XMODEM ( )

inlinestatic

Returns a set of parameters for CRC-16 XMODEM (aka CRC-16 ZMODEM, CRC-16 ACORN, CRC-16 LTE).

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-16 XMODEM has the following parameters and check value:

polynomial = 0x1021
initial value = 0x0000
final XOR = 0x0000
reflect input = false
reflect output = false
check value = 0x31C3

Returns: CRC-16 XMODEM parameters

Definition at line 1437 of file crc.h.

const CRC::Parameters< crcpp_uint32, 32 > & CRC::CRC_32 ( )

inlinestatic

Returns a set of parameters for CRC-32 (aka CRC-32 ADCCP, CRC-32 PKZip).

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-32 has the following parameters and check value:

polynomial = 0x04C11DB7
initial value = 0xFFFFFFFF
final XOR = 0xFFFFFFFF
reflect input = true
reflect output = true
check value = 0xCBF43926

Returns: CRC-32 parameters

Definition at line 1565 of file crc.h.

const CRC::Parameters< crcpp_uint32, 32 > & CRC::CRC_32_BZIP2 ( )

inlinestatic

Returns a set of parameters for CRC-32 BZIP2 (aka CRC-32 AAL5, CRC-32 DECT-B, CRC-32 B-CRC).

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-32 BZIP2 has the following parameters and check value:

polynomial = 0x04C11DB7
initial value = 0xFFFFFFFF
final XOR = 0xFFFFFFFF
reflect input = false
reflect output = false
check value = 0xFC891918

Returns: CRC-32 BZIP2 parameters

Definition at line 1583 of file crc.h.

const CRC::Parameters< crcpp_uint32, 32 > & CRC::CRC_32_MPEG2 ( )

inlinestatic

Returns a set of parameters for CRC-32 MPEG-2.

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-32 MPEG-2 has the following parameters and check value:

polynomial = 0x04C11DB7
initial value = 0xFFFFFFFF
final XOR = 0x00000000
reflect input = false
reflect output = false
check value = 0x0376E6E7

Returns: CRC-32 MPEG-2 parameters

Definition at line 1621 of file crc.h.

const CRC::Parameters< crcpp_uint32, 32 > & CRC::CRC_32_POSIX ( )

inlinestatic

Returns a set of parameters for CRC-32 POSIX.

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-32 POSIX has the following parameters and check value:

polynomial = 0x04C11DB7
initial value = 0x00000000
final XOR = 0xFFFFFFFF
reflect input = false
reflect output = false
check value = 0x765E7680

Returns: CRC-32 POSIX parameters

Definition at line 1639 of file crc.h.

const CRC::Parameters< crcpp_uint8, 8 > & CRC::CRC_8 ( )

inlinestatic

Returns a set of parameters for CRC-8 SMBus.

Note

The parameters are static and are delayed-constructed to reduce memory footprint.

CRC-8 SMBus has the following parameters and check value:

polynomial = 0x07
initial value = 0x00
final XOR = 0x00
reflect input = false
reflect output = false
check value = 0xF4

Returns: CRC-8 SMBus parameters

Definition at line 926 of file crc.h.

template<typename CRCType , crcpp_uint16 CRCWidth>

CRCType CRC::Finalize	(	CRCType	remainder,
		CRCType	finalXOR,
		bool	reflectOutput
	)

inlinestaticprivate

Computes the final reflection and XOR of a CRC remainder.

Parameters

[in]	remainder	CRC remainder to reflect and XOR
[in]	finalXOR	Final value to XOR with the remainder
[in]	reflectOutput	true to reflect each byte of the remainder before the XOR

Template Parameters

CRCType	Integer type for storing the CRC result
CRCWidth	Number of bits in the CRC

Returns: Final CRC

Definition at line 542 of file crc.h.

CRC& CRC::operator= ( const CRC & other )

private

template<typename IntegerType >

IntegerType CRC::Reflect	(	IntegerType	value,
		crcpp_uint16	numBits
	)

inlinestaticprivate

Reflects (i.e. reverses the bits within) an integer value.

Parameters

[in]	value	Value to reflect
[in]	numBits	Number of bits in the integer which will be reflected

Template Parameters

IntegerType Integer type of the value being reflected

Returns: Reflected value

Definition at line 519 of file crc.h.

template<typename CRCType , crcpp_uint16 CRCWidth>

CRCType CRC::UndoFinalize	(	CRCType	crc,
		CRCType	finalXOR,
		bool	reflectOutput
	)

inlinestaticprivate

Undoes the process of computing the final reflection and XOR of a CRC remainder.

Note

This function allows for computation of multi-part CRCs

Calling UndoFinalize() followed by Finalize() (or vice versa) will always return the original remainder value:

CRCType x = ...;
CRCType y = Finalize(x, finalXOR, reflectOutput);
CRCType z = UndoFinalize(y, finalXOR, reflectOutput);
assert(x == z);

Parameters

[in]	crc	Reflected and XORed CRC
[in]	finalXOR	Final value XORed with the remainder
[in]	reflectOutput	true if the remainder is to be reflected

Template Parameters

CRCType	Integer type for storing the CRC result
CRCWidth	Number of bits in the CRC

Returns: Un-finalized CRC remainder

Definition at line 574 of file crc.h.

The documentation for this class was generated from the following file:

crc.h

Classes

Static Public Member Functions

Private Member Functions

Static Private Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation