ulid Namespace Reference

Classes
struct	ULID

Typedefs
typedef __uint128_t	ULID

Functions
void	EncodeTime (time_t timestamp, ULID &ulid)
void	EncodeTimeNow (ULID &ulid)
void	EncodeTimeSystemClockNow (ULID &ulid)
void	EncodeEntropy (const std::function< uint8_t()> &rng, ULID &ulid)
void	EncodeEntropyRand (ULID &ulid)
std::uniform_int_distribution< uint8_t >	Distribution_0_255 (0, 255)
void	EncodeEntropyMt19937 (std::mt19937 &generator, ULID &ulid)
void	Encode (time_t timestamp, const std::function< uint8_t()> &rng, ULID &ulid)
void	EncodeNowRand (ULID &ulid)
ULID	Create (time_t timestamp, const std::function< uint8_t()> &rng)
ULID	CreateNowRand ()
void	MarshalTo (const ULID &ulid, char dst[26])
std::string	Marshal (const ULID &ulid)
void	MarshalBinaryTo (const ULID &ulid, uint8_t dst[16])
std::vector< uint8_t >	MarshalBinary (const ULID &ulid)
void	UnmarshalFrom (const char str[26], ULID &ulid)
ULID	Unmarshal (const std::string &str)
void	UnmarshalBinaryFrom (const uint8_t b[16], ULID &ulid)
ULID	UnmarshalBinary (const std::vector< uint8_t > &b)
int	CompareULIDs (const ULID &ulid1, const ULID &ulid2)
time_t	Time (const ULID &ulid)

Variables
const char	Encoding [33] = "0123456789ABCDEFGHJKMNPQRSTVWXYZ"
const uint8_t	dec [256]

Typedef Documentation

typedef __uint128_t ulid::ULID

ULID is a 16 byte Universally Unique Lexicographically Sortable Identifier

Function Documentation

int ulid::CompareULIDs	(	const ULID &	ulid1,
		const ULID &	ulid2
	)

CompareULIDs will compare two ULIDs. returns: -1 if ulid1 is Lexicographically before ulid2 1 if ulid1 is Lexicographically after ulid2 0 if ulid1 is same as ulid2

ULID ulid::Create	(	time_t	timestamp,
		const std::function< uint8_t()> &	rng
	)

Create will create a ULID with a timestamp and a generator.

ULID ulid::CreateNowRand

(

)

CreateNowRand:EncodeNowRand = Create:Encode.

std::uniform_int_distribution< uint8_t > ulid::Distribution_0_255	(	0	,
		255
	)

void ulid::Encode	(	time_t	timestamp,
		const std::function< uint8_t()> &	rng,
		ULID &	ulid
	)

Encode will create an encoded ULID with a timestamp and a generator.

void ulid::EncodeEntropy	(	const std::function< uint8_t()> &	rng,
		ULID &	ulid
	)

EncodeEntropy will encode the last 10 bytes of the passed uint8_t array with the values generated using the passed random number generator.

void ulid::EncodeEntropyMt19937	(	std::mt19937 &	generator,
		ULID &	ulid
	)

EncodeEntropyMt19937 will encode a ulid using std::mt19937

It also creates a std::uniform_int_distribution to generate values in [0, 255]

void ulid::EncodeEntropyRand

(

ULID &

ulid

)

EncodeEntropyRand will encode a ulid using std::rand

std::rand returns values in [0, RAND_MAX]

void ulid::EncodeNowRand

(

ULID &

ulid

)

EncodeNowRand = EncodeTimeNow + EncodeEntropyRand.

void ulid::EncodeTime	(	time_t	timestamp,
		ULID &	ulid
	)

EncodeTime will encode the first 6 bytes of a uint8_t array to the passed timestamp

void ulid::EncodeTimeNow

(

ULID &

ulid

)

EncodeTimeNow will encode a ULID using the time obtained using std::time(nullptr)

void ulid::EncodeTimeSystemClockNow

(

ULID &

ulid

)

EncodeTimeSystemClockNow will encode a ULID using the time obtained using std::chrono::system_clock::now() by taking the timestamp in milliseconds.

std::string ulid::Marshal

(

const ULID &

ulid

)

Marshal will marshal a ULID to a std::string.

std::vector< uint8_t > ulid::MarshalBinary

(

const ULID &

ulid

)

MarshalBinary will Marshal a ULID to a byte vector.

void ulid::MarshalBinaryTo	(	const ULID &	ulid,
		uint8_t	dst[16]
	)

MarshalBinaryTo will Marshal a ULID to the passed byte array

void ulid::MarshalTo	(	const ULID &	ulid,
		char	dst[26]
	)

MarshalTo will marshal a ULID to the passed character array.

Implementation taken directly from oklog/ulid (https://sourcegraph.com/github.com/oklog/ulid@0774f81f6e44af5ce5e91c8d7d76cf710e889ebb/-/blob/ulid.go#L162-190)

timestamp:
dst[0]: first 3 bits of data[0]
dst[1]: last 5 bits of data[0]
dst[2]: first 5 bits of data[1]
dst[3]: last 3 bits of data[1] + first 2 bits of data[2]
dst[4]: bits 3-7 of data[2]
dst[5]: last bit of data[2] + first 4 bits of data[3]
dst[6]: last 4 bits of data[3] + first bit of data[4]
dst[7]: bits 2-6 of data[4]
dst[8]: last 2 bits of data[4] + first 3 bits of data[5]
dst[9]: last 5 bits of data[5]

entropy: follows similarly, except now all components are set to 5 bits.

MarshalTo will marshal a ULID to the passed character array.

Implementation taken directly from oklog/ulid (https://sourcegraph.com/github.com/oklog/ulid@0774f81f6e44af5ce5e91c8d7d76cf710e889ebb/-/blob/ulid.go#L162-190)

timestamp: dst[0]: first 3 bits of data[0] dst[1]: last 5 bits of data[0] dst[2]: first 5 bits of data[1] dst[3]: last 3 bits of data[1] + first 2 bits of data[2] dst[4]: bits 3-7 of data[2] dst[5]: last bit of data[2] + first 4 bits of data[3] dst[6]: last 4 bits of data[3] + first bit of data[4] dst[7]: bits 2-6 of data[4] dst[8]: last 2 bits of data[4] + first 3 bits of data[5] dst[9]: last 5 bits of data[5]

entropy: follows similarly, except now all components are set to 5 bits.

time_t ulid::Time

(

const ULID &

ulid

)

Time will extract the timestamp used to generate a ULID

ULID ulid::Unmarshal

(

const std::string &

str

)

Unmarshal will create a new ULID by unmarshaling the passed string.

ULID ulid::UnmarshalBinary

(

const std::vector< uint8_t > &

b

)

Unmarshal will create a new ULID by unmarshaling the passed byte vector.

void ulid::UnmarshalBinaryFrom	(	const uint8_t	b[16],
		ULID &	ulid
	)

UnmarshalBinaryFrom will unmarshal a ULID from the passed byte array.

void ulid::UnmarshalFrom	(	const char	str[26],
		ULID &	ulid
	)

UnmarshalFrom will unmarshal a ULID from the passed character array.

Variable Documentation

const uint8_t ulid::dec

dec storesdecimal encodings for characters. 0xFF indicates invalid character. 48-57 are digits. 65-90 are capital alphabets.

const char ulid::Encoding = "0123456789ABCDEFGHJKMNPQRSTVWXYZ"

Crockford's Base32