Enum TagEncoding

Source

pub enum TagEncoding {
    Direct,
    Niche {
        untagged_variant: VariantIdx,
        niche_variants: RangeInclusive<VariantIdx>,
        niche_start: u128,
    },
}

Variants§

§

Direct

The tag directly stores the discriminant, but possibly with a smaller layout (so converting the tag to the discriminant can require sign extension).

§

Niche

Niche (values invalid for a type) encoding the discriminant: Discriminant and variant index coincide. The variant untagged_variant contains a niche at an arbitrary offset (field tag_field of the enum), which for a variant with discriminant d is set to (d - niche_variants.start).wrapping_add(niche_start).

For example, Option<(usize, &T)> is represented such that None has a null pointer for the second tuple field, and Some is the identity function (with a non-null reference).

Fields

§untagged_variant: VariantIdx

§niche_variants: RangeInclusive<VariantIdx>

§niche_start: u128

Enum TagEncodingCopy item path

Variants§

Direct

Niche

Fields

Trait Implementations§

impl Clone for TagEncoding

fn clone(&self) -> TagEncoding

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

impl Debug for TagEncoding

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

impl Hash for TagEncoding

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

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

impl PartialEq for TagEncoding

fn eq(&self, other: &TagEncoding) -> bool

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

impl Serialize for TagEncoding

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>where __S: Serializer,

impl Eq for TagEncoding

impl StructuralPartialEq for TagEncoding

Auto Trait Implementations§

impl DynSend for TagEncoding

impl DynSync for TagEncoding

impl Freeze for TagEncoding

impl RefUnwindSafe for TagEncoding

impl Send for TagEncoding

impl Sync for TagEncoding

impl Unpin for TagEncoding

impl UnwindSafe for TagEncoding

Blanket Implementations§

impl<T> Aligned for T

const ALIGN: Alignment

impl<T> Any for Twhere T: 'static + ?Sized,

fn type_id(&self) -> TypeId

impl<T> AnyEq for Twhere T: Any + PartialEq,

fn equals(&self, other: &(dyn Any + 'static)) -> bool

fn as_any(&self) -> &(dyn Any + 'static)

impl<T> Borrow<T> for Twhere T: ?Sized,

fn borrow(&self) -> &T

impl<T> BorrowMut<T> for Twhere T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

impl<T> CloneToUninit for Twhere T: Clone,

unsafe fn clone_to_uninit(&self, dest: *mut u8)

impl<T, R> CollectAndApply<T, R> for T

fn collect_and_apply<I, F>(iter: I, f: F) -> Rwhere I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

type Output = R

impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

fn equivalent(&self, key: &K) -> bool

impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

fn equivalent(&self, key: &K) -> bool

impl<T> Filterable for T

fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(DataRequest<'_>) -> bool>

impl<T> From<T> for T

fn from(t: T) -> T

impl<T> Instrument for T

fn instrument(self, span: Span) -> Instrumented<Self>

fn in_current_span(self) -> Instrumented<Self>

impl<T, U> Into<U> for Twhere U: From<T>,

fn into(self) -> U

impl<T> IntoEither for T

fn into_either(self, into_left: bool) -> Either<Self, Self>

fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>where F: FnOnce(&Self) -> bool,

impl<P> IntoQueryParam<P> for P

fn into_query_param(self) -> P

impl<T> MaybeResult<T> for T

type Error = !

fn from(_: Result<T, <T as MaybeResult<T>>::Error>) -> T

fn to_result(self) -> Result<T, <T as MaybeResult<T>>::Error>

impl<T> Pointable for T

const ALIGN: usize

type Init = T

unsafe fn init(init: <T as Pointable>::Init) -> usize

unsafe fn deref<'a>(ptr: usize) -> &'a T

unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

unsafe fn drop(ptr: usize)

impl<T> Same for T

type Output = T

impl<T> ToOwned for Twhere T: Clone,

type Owned = T

Enum TagEncoding

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

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

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where S: Serializer,

impl<T> Any for T
where T: 'static + ?Sized,

impl<T> AnyEq for T
where T: Any + PartialEq,

impl<T> Borrow<T> for T
where T: ?Sized,

impl<T> BorrowMut<T> for T
where T: ?Sized,

impl<T> CloneToUninit for T
where T: Clone,

fn collect_and_apply<I, F>(iter: I, f: F) -> R
where I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

impl<T, U> Into<U> for T
where U: From<T>,

fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

impl<T> ToOwned for T
where T: Clone,

impl<T, U> TryFrom<U> for T
where U: Into<T>,

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

impl<I, T, U> Upcast<I, U> for T
where U: UpcastFrom<I, T>,

impl<V, T> VZip<V> for T
where V: MultiLane<T>,

impl<Tcx, T> Value<Tcx> for T
where Tcx: DepContext,

fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

impl<T> ErasedDestructor for T
where T: 'static,

impl<T> MaybeSendSync for T
where T: Send + Sync,