Struct uuid::Uuid

This uses the getrandom crate to utilise the operating system’s RNG as the source of random numbers. If you’d like to use a custom generator, don’t use this method: generate random bytes using your custom generator and pass them to the uuid::Builder::from_bytes function instead.

Note that usage of this method requires the v4 feature of this crate to be enabled.

Examples

Basic usage:

use uuid::Uuid;

let uuid = Uuid::new_v4();

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impl Uuid

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pub const NAMESPACE_DNS: Self = _

UUID namespace for Domain Name System (DNS).

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pub const NAMESPACE_OID: Self = _

UUID namespace for ISO Object Identifiers (OIDs).

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pub const NAMESPACE_URL: Self = _

UUID namespace for Uniform Resource Locators (URLs).

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pub const NAMESPACE_X500: Self = _

UUID namespace for X.500 Distinguished Names (DNs).

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pub fn get_variant(&self) -> Option<Variant>

Returns the variant of the UUID structure.

This determines the interpretation of the structure of the UUID. Currently only the RFC4122 variant is generated by this module.

Variant Reference

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pub const fn get_version_num(&self) -> usize

Returns the version number of the UUID.

This represents the algorithm used to generate the contents.

Currently only the Random (V4) algorithm is supported by this module. There are security and privacy implications for using older versions - see Wikipedia: Universally Unique Identifier for details.

Version Reference

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pub fn get_version(&self) -> Option<Version>

Returns the version of the UUID.

This represents the algorithm used to generate the contents

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pub fn as_fields(&self) -> (u32, u16, u16, &[u8; 8])

Returns the four field values of the UUID in big-endian order.

These values can be passed to the from_fields() method to get the original Uuid back.

The first field value represents the first group of (eight) hex digits, taken as a big-endian u32 value. For V1 UUIDs, this field represents the low 32 bits of the timestamp.
The second field value represents the second group of (four) hex digits, taken as a big-endian u16 value. For V1 UUIDs, this field represents the middle 16 bits of the timestamp.
The third field value represents the third group of (four) hex digits, taken as a big-endian u16 value. The 4 most significant bits give the UUID version, and for V1 UUIDs, the last 12 bits represent the high 12 bits of the timestamp.
The last field value represents the last two groups of four and twelve hex digits, taken in order. The first 1-3 bits of this indicate the UUID variant, and for V1 UUIDs, the next 13-15 bits indicate the clock sequence and the last 48 bits indicate the node ID.

Examples

use uuid::Uuid;

fn main() -> Result<(), uuid::Error> {
    let uuid = Uuid::nil();
    assert_eq!(uuid.as_fields(), (0, 0, 0, &[0u8; 8]));

    let uuid = Uuid::parse_str("936DA01F-9ABD-4D9D-80C7-02AF85C822A8")?;
    assert_eq!(
        uuid.as_fields(),
        (
            0x936DA01F,
            0x9ABD,
            0x4D9D,
            b"\x80\xC7\x02\xAF\x85\xC8\x22\xA8"
        )
    );

    Ok(())
}

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pub fn to_fields_le(&self) -> (u32, u16, u16, &[u8; 8])

Returns the four field values of the UUID in little-endian order.

The bytes in the returned integer fields will be converted from big-endian order.

Examples

use uuid::Uuid;

fn main() -> Result<(), uuid::Error> {
    let uuid = Uuid::parse_str("936DA01F-9ABD-4D9D-80C7-02AF85C822A8")?;
    assert_eq!(
        uuid.to_fields_le(),
        (
            0x1FA06D93,
            0xBD9A,
            0x9D4D,
            b"\x80\xC7\x02\xAF\x85\xC8\x22\xA8"
        )
    );
    Ok(())
}

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pub fn as_u128(&self) -> u128

Returns a 128bit value containing the UUID data.

The bytes in the UUID will be packed into a u128, like the Uuid::as_bytes method.

Examples

use uuid::Uuid;

fn main() -> Result<(), uuid::Error> {
    let uuid = Uuid::parse_str("936DA01F-9ABD-4D9D-80C7-02AF85C822A8")?;
    assert_eq!(
        uuid.as_u128(),
        0x936DA01F9ABD4D9D80C702AF85C822A8,
    );
    Ok(())
}

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pub fn to_u128_le(&self) -> u128

Returns a 128bit little-endian value containing the UUID data.

The bytes in the UUID will be reversed and packed into a u128. Note that this will produce a different result than Uuid::to_fields_le, because the entire UUID is reversed, rather than reversing the individual fields in-place.

Examples

use uuid::Uuid;

fn main() -> Result<(), uuid::Error> {
    let uuid = Uuid::parse_str("936DA01F-9ABD-4D9D-80C7-02AF85C822A8")?;

    assert_eq!(
        uuid.to_u128_le(),
        0xA822C885AF02C7809D4DBD9A1FA06D93,
    );
    Ok(())
}

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pub const fn as_bytes(&self) -> &Bytes

Returns an array of 16 octets containing the UUID data.

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pub fn is_nil(&self) -> bool

Tests if the UUID is nil.

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pub const fn encode_buffer() -> [u8; 45]

A buffer that can be used for encode_... calls, that is guaranteed to be long enough for any of the adapters.

Examples

use uuid::Uuid;

let uuid = Uuid::nil();

assert_eq!(
    uuid.to_simple().encode_lower(&mut Uuid::encode_buffer()),
    "00000000000000000000000000000000"
);

assert_eq!(
    uuid.to_hyphenated()
        .encode_lower(&mut Uuid::encode_buffer()),
    "00000000-0000-0000-0000-000000000000"
);

assert_eq!(
    uuid.to_urn().encode_lower(&mut Uuid::encode_buffer()),
    "urn:uuid:00000000-0000-0000-0000-000000000000"
);