uuid #

Description

uuid generates and parses UUIDs (Universally Unique Identifiers) as defined in RFC 9562.

A uuid.UUID is a [16]u8, so UUIDs can be compared with == and used as map keys. The random bits of new UUIDs come from the cryptographically secure random number generator of the operating system (crypto.rand).

• uuid.new() returns a new UUID made with an algorithm suitable for most purposes; at this time it is the same as uuid.new_v4().
• uuid.new_v4() returns a random (version 4) UUID, with 122 random bits.
• uuid.new_v7() returns a time-ordered (version 7) UUID: the Unix time in milliseconds, a 12-bit fraction of the millisecond and 62 random bits. The UUIDs it returns always sort in increasing order, except when the system clock moves backwards.
• uuid.parse(s) accepts f81d4fae-7dec-11d0-a765-00a0c91e6bf6, {f81d4fae-7dec-11d0-a765-00a0c91e6bf6}, urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6 and f81d4fae7dec11d0a76500a0c91e6bf6, with hexadecimal digits in any case.
• u.str() returns the lowercase hex-and-dash form, and u.compare(v) orders UUIDs by their bytes, as RFC 9562 does.
• uuid.nil_uuid and uuid.max_uuid are the Nil and the Max UUIDs.

The module is a port of the uuid package of Go.

Examples

import uuid

fn main() {
    id := uuid.parse('{F81D4FAE-7DEC-11D0-A765-00A0C91E6BF6}') or { panic(err) }
    println(id.str())
    println(id == uuid.parse('f81d4fae7dec11d0a76500a0c91e6bf6') or { panic(err) })

    mut ids := [uuid.max_uuid, id, uuid.nil_uuid]
    ids.sort_with_compare(fn (a &uuid.UUID, b &uuid.UUID) int {
        return a.compare(*b)
    })
    for u in ids {
        println(u.str())
    }

    mut seen := map[uuid.UUID]bool{}
    seen[uuid.new_v7()] = true
    println(seen.len)
}

f81d4fae-7dec-11d0-a765-00a0c91e6bf6
true
00000000-0000-0000-0000-000000000000
f81d4fae-7dec-11d0-a765-00a0c91e6bf6
ffffffff-ffff-ffff-ffff-ffffffffffff
1

fn new() UUID

new returns a new UUID, generated with an algorithm suitable for most purposes. At this time it is the same as new_v4.

fn new_v4() UUID

new_v4 returns a new version 4 UUID, which holds 122 random bits.

fn new_v7() UUID

new_v7 returns a new version 7 UUID: the Unix time in milliseconds in its 48 most significant bits, then a 12-bit fraction of the millisecond and 62 random bits. The UUIDs it returns always sort in increasing order, except when the system clock moves backwards.

fn parse(s string) !UUID

parse returns the UUID represented by s, which can be in any of the forms f81d4fae-7dec-11d0-a765-00a0c91e6bf6, {f81d4fae-7dec-11d0-a765-00a0c91e6bf6}, urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6 or f81d4fae7dec11d0a76500a0c91e6bf6. The hexadecimal digits may be in any case.

type UUID = [16]u8

UUID is a Universally Unique Identifier as specified in RFC 9562. UUIDs can be compared with == and used as map keys.

fn (u UUID) str() string

str returns the lowercase hex-and-dash form of u defined in RFC 9562, like f81d4fae-7dec-11d0-a765-00a0c91e6bf6.

fn (u UUID) compare(v UUID) int

compare returns -1 if u sorts before v, 1 if it sorts after v, and 0 if they are the same, in the big-endian byte order of section 6.11 of RFC 9562.