Struct zng::state_map::StateId

pub struct StateId<T>(/* private fields */)
where
    T: StateValue;

Unique identifier of a value in a state map.

The type T is the value type.

static_id! {
    static ref FOO_ID: StateId<bool>;
}

let mut owned_state = OwnedStateMap::<()>::default();
let foo = owned_state.borrow_mut().set(*FOO_ID, true);

Memory

The internal number is a NonZeroU64, that means that Option<StateId> and StateId are the same size as u64.

As Hash

The generated internal number has good statistical distribution and can be used as its own hash, although it is not cryptographically safe, as it is simply a sequential counter scrambled using splitmix64.

Static

The unique ID cannot be generated at compile time, but you can use the static_id! macro to declare a lazy static that instantiates the ID.

Implementations

impl<T> StateId<T>

where T: StateValue,

pub fn new_unique() -> StateId<T>

Generates a new unique ID.

pub fn get(self) -> u64

Retrieve the underlying value.

pub fn sequential(self) -> u64

Un-scramble the underlying value to get the original sequential count number.

If two IDs, id0 and id1 where generated by the same thread then id0.sequential() < id1.sequential().

pub fn from_raw(raw: u64) -> StateId<T>

Creates an ID from a raw value.

The value must not be zero, panics if it is, the value must have been provided by get otherwise the ID will not be unique.

pub fn from_sequential(num: u64) -> StateId<T>

Creates an ID from a sequential number.

Safety

The value must not be zero, panics if it is, the value must have been provided by sequential otherwise the ID will not be unique.

Trait Implementations

impl<T> Clone for StateId<T>

where T: StateValue,

fn clone(&self) -> StateId<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> Debug for StateId<T>

where T: StateValue,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<T> Hash for StateId<T>

where T: StateValue,

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T> PartialEq for StateId<T>

where T: StateValue,

fn eq(&self, other: &StateId<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T> UniqueId for StateId<T>

where T: StateValue,

fn new_unique() -> StateId<T>

New unique ID.

impl<T> Copy for StateId<T>

where T: StateValue,

impl<T> Eq for StateId<T>

where T: StateValue,

impl<T> NoUninit for StateId<T>

where T: StateValue,

impl<T> PodInOption for StateId<T>

where T: StateValue,

impl<T> ZeroableInOption for StateId<T>

where T: StateValue,