ulid – github.com/oklog/ulid Index | Examples | Files | Directories

package ulid

import "github.com/oklog/ulid"

Index

Examples

Constants 

const EncodedSize = 26

EncodedSize is the length of a text encoded ULID. 

const Encoding = "0123456789ABCDEFGHJKMNPQRSTVWXYZ"

Encoding is the base 32 encoding alphabet used in ULID strings.

Variables 

var (
	// ErrDataSize is returned when parsing or unmarshaling ULIDs with the wrong
	// data size.
	ErrDataSize = errors.New("ulid: bad data size when unmarshaling")

	// ErrInvalidCharacters is returned when parsing or unmarshaling ULIDs with
	// invalid Base32 encodings.
	ErrInvalidCharacters = errors.New("ulid: bad data characters when unmarshaling")

	// ErrBufferSize is returned when marshalling ULIDs to a buffer of insufficient
	// size.
	ErrBufferSize = errors.New("ulid: bad buffer size when marshaling")

	// ErrBigTime is returned when constructing an ULID with a time that is larger
	// than MaxTime.
	ErrBigTime = errors.New("ulid: time too big")

	// ErrOverflow is returned when unmarshaling a ULID whose first character is
	// larger than 7, thereby exceeding the valid bit depth of 128.
	ErrOverflow = errors.New("ulid: overflow when unmarshaling")

	// ErrScanValue is returned when the value passed to scan cannot be unmarshaled
	// into the ULID.
	ErrScanValue = errors.New("ulid: source value must be a string or byte slice")
)

Functions

func MaxTime 

func MaxTime() uint64

MaxTime returns the maximum Unix time in milliseconds that can be encoded in an ULID.

func Now 

func Now() uint64

Now is a convenience function that returns the current UTC time in Unix milliseconds. Equivalent to: 

Timestamp(time.Now().UTC())

func Timestamp 

func Timestamp(t time.Time) uint64

Timestamp converts a time.Time to Unix milliseconds.

Because of the way ULID stores time, times from the year 10889 produces undefined results.

Types

type ULID 

type ULID [16]byte

An ULID is a 16 byte Universally Unique Lexicographically Sortable Identifier 

The components are encoded as 16 octets.
Each component is encoded with the MSB first (network byte order).

0                   1                   2                   3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                      32_bit_uint_time_high                    |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|     16_bit_uint_time_low      |       16_bit_uint_random      |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                       32_bit_uint_random                      |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                       32_bit_uint_random                      |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Example

Code:play  

package main

import (
	"fmt"
	"math/rand"
	"time"

	"github.com/oklog/ulid"
)

func main() {
	t := time.Unix(1000000, 0)
	entropy := rand.New(rand.NewSource(t.UnixNano()))
	fmt.Println(ulid.MustNew(ulid.Timestamp(t), entropy))
}

Output:

0000XSNJG0MQJHBF4QX1EFD6Y3

func MustNew 

func MustNew(ms uint64, entropy io.Reader) ULID

MustNew is a convenience function equivalent to New that panics on failure instead of returning an error.

func MustParse 

func MustParse(ulid string) ULID

MustParse is a convenience function equivalent to Parse that panics on failure instead of returning an error.

func MustParseStrict 

func MustParseStrict(ulid string) ULID

MustParseStrict is a convenience function equivalent to ParseStrict that panics on failure instead of returning an error.

func New 

func New(ms uint64, entropy io.Reader) (id ULID, err error)

New returns an ULID with the given Unix milliseconds timestamp and an optional entropy source. Use the Timestamp function to convert a time.Time to Unix milliseconds.

ErrBigTime is returned when passing a timestamp bigger than MaxTime. Reading from the entropy source may also return an error.

func Parse 

func Parse(ulid string) (id ULID, err error)

Parse parses an encoded ULID, returning an error in case of failure.

ErrDataSize is returned if the len(ulid) is different from an encoded ULID's length. Invalid encodings produce undefined ULIDs. For a version that returns an error instead, see ParseStrict.

func ParseStrict 

func ParseStrict(ulid string) (id ULID, err error)

ParseStrict parses an encoded ULID, returning an error in case of failure.

It is like Parse, but additionally validates that the parsed ULID consists only of valid base32 characters. It is slightly slower than Parse.

ErrDataSize is returned if the len(ulid) is different from an encoded ULID's length. Invalid encodings return ErrInvalidCharacters.

func (ULID) Compare 

func (id ULID) Compare(other ULID) int

Compare returns an integer comparing id and other lexicographically. The result will be 0 if id==other, -1 if id < other, and +1 if id > other.

func (ULID) Entropy 

func (id ULID) Entropy() []byte

Entropy returns the entropy from the ULID.

func (ULID) MarshalBinary 

func (id ULID) MarshalBinary() ([]byte, error)

MarshalBinary implements the encoding.BinaryMarshaler interface by returning the ULID as a byte slice.

func (ULID) MarshalBinaryTo 

func (id ULID) MarshalBinaryTo(dst []byte) error

MarshalBinaryTo writes the binary encoding of the ULID to the given buffer. ErrBufferSize is returned when the len(dst) != 16.

func (ULID) MarshalText 

func (id ULID) MarshalText() ([]byte, error)

MarshalText implements the encoding.TextMarshaler interface by returning the string encoded ULID.

func (ULID) MarshalTextTo 

func (id ULID) MarshalTextTo(dst []byte) error

MarshalTextTo writes the ULID as a string to the given buffer. ErrBufferSize is returned when the len(dst) != 26.

func (*ULID) Scan 

func (id *ULID) Scan(src interface{}) error

Scan implements the sql.Scanner interface. It supports scanning a string or byte slice.

func (*ULID) SetEntropy 

func (id *ULID) SetEntropy(e []byte) error

SetEntropy sets the ULID entropy to the passed byte slice. ErrDataSize is returned if len(e) != 10.

func (*ULID) SetTime 

func (id *ULID) SetTime(ms uint64) error

SetTime sets the time component of the ULID to the given Unix time in milliseconds.

func (ULID) String 

func (id ULID) String() string

String returns a lexicographically sortable string encoded ULID (26 characters, non-standard base 32) e.g. 01AN4Z07BY79KA1307SR9X4MV3 Format: tttttttttteeeeeeeeeeeeeeee where t is time and e is entropy

func (ULID) Time 

func (id ULID) Time() uint64

Time returns the Unix time in milliseconds encoded in the ULID.

func (*ULID) UnmarshalBinary 

func (id *ULID) UnmarshalBinary(data []byte) error

UnmarshalBinary implements the encoding.BinaryUnmarshaler interface by copying the passed data and converting it to an ULID. ErrDataSize is returned if the data length is different from ULID length.

func (*ULID) UnmarshalText 

func (id *ULID) UnmarshalText(v []byte) error

UnmarshalText implements the encoding.TextUnmarshaler interface by parsing the data as string encoded ULID.

ErrDataSize is returned if the len(v) is different from an encoded ULID's length. Invalid encodings produce undefined ULIDs.

func (ULID) Value 

func (id ULID) Value() (driver.Value, error)

Value implements the sql/driver.Valuer interface. This returns the value represented as a byte slice. If instead a string is desirable, a wrapper type can be created that calls String(). 

// stringValuer wraps a ULID as a string-based driver.Valuer.
type stringValuer ULID

func (id stringValuer) Value() (driver.Value, error) {
	return ULID(id).String(), nil
}

// Example usage.
db.Exec("...", stringValuer(id))

Source Files

ulid.go

Directories

PathSynopsis
cmd
cmd/ulid
Version
v1.0.0
Published
Jul 20, 2018
Platform
windows/amd64
Imports
5 packages
Last checked
2 days ago –

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