Utilities to assist with implementing big number arithmetic. More...

#include <BigNumberUtil.h>

Static Public Member Functions
static void	unpackLE (limb_t limbs, size_t count, const uint8_t bytes, size_t len)
	Unpacks the little-endian byte representation of a big number into a limb array. More...

static void	unpackBE (limb_t limbs, size_t count, const uint8_t bytes, size_t len)
	Unpacks the big-endian byte representation of a big number into a limb array. More...

static void	packLE (uint8_t bytes, size_t len, const limb_t limbs, size_t count)
	Packs the little-endian byte representation of a big number into a byte array. More...

static void	packBE (uint8_t bytes, size_t len, const limb_t limbs, size_t count)
	Packs the big-endian byte representation of a big number into a byte array. More...

Detailed Description

Utilities to assist with implementing big number arithmetic.

Big numbers are represented as arrays of limb_t words, which may be 8 bits, 16 bits, or 32 bits in size depending upon how the library was configured. For AVR, 16 bit limbs usually give the best performance.

Limb arrays are ordered from the least significant word to the most significant.

Definition at line 52 of file BigNumberUtil.h.

Member Function Documentation

void BigNumberUtil::packBE	(	uint8_t *	bytes,
		size_t	len,
		const limb_t *	limbs,
		size_t	count
	)

static

Packs the big-endian byte representation of a big number into a byte array.

Parameters

bytes	The byte array to pack into.
len	The number of bytes in the destination bytes array.
limbs	The limb array representing the big number, starting with the least significant word.
count	The number of elements in the limbs array.

If len is shorter than the length of limbs, then the number will be truncated to the least significant len bytes. If len is longer than the length of limbs, then the high bytes will be filled with zeroes.

See Also: unpackLE(), packBE()

Definition at line 293 of file BigNumberUtil.cpp.

void BigNumberUtil::packLE	(	uint8_t *	bytes,
		size_t	len,
		const limb_t *	limbs,
		size_t	count
	)

static

Packs the little-endian byte representation of a big number into a byte array.

Parameters

bytes	The byte array to pack into.
len	The number of bytes in the destination bytes array.
limbs	The limb array representing the big number, starting with the least significant word.
count	The number of elements in the limbs array.

If len is shorter than the length of limbs, then the number will be truncated to the least significant len bytes. If len is longer than the length of limbs, then the high bytes will be filled with zeroes.

See Also: unpackLE(), packBE()

Definition at line 207 of file BigNumberUtil.cpp.

void BigNumberUtil::unpackBE	(	limb_t *	limbs,
		size_t	count,
		const uint8_t *	bytes,
		size_t	len
	)

static

Unpacks the big-endian byte representation of a big number into a limb array.

Parameters

limbs	The limb array, starting with the least significant word.
count	The number of elements in the limbs array.
bytes	The bytes to unpack.
len	The number of bytes to unpack.

If len is shorter than the length of limbs, then the high bytes will be filled with zeroes. If len is longer than the length of limbs, then the high bytes will be truncated and lost.

See Also: packBE(), unpackLE()

Definition at line 133 of file BigNumberUtil.cpp.

void BigNumberUtil::unpackLE	(	limb_t *	limbs,
		size_t	count,
		const uint8_t *	bytes,
		size_t	len
	)

static

Unpacks the little-endian byte representation of a big number into a limb array.

Parameters

limbs	The limb array, starting with the least significant word.
count	The number of elements in the limbs array.
bytes	The bytes to unpack.
len	The number of bytes to unpack.

If len is shorter than the length of limbs, then the high bytes will be filled with zeroes. If len is longer than the length of limbs, then the high bytes will be truncated and lost.

See Also: packLE(), unpackBE()

Definition at line 54 of file BigNumberUtil.cpp.

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

Static Public Member Functions

Detailed Description

Member Function Documentation