Struct index_ext::tag::Len

pub struct Len<Tag> { /* fields omitted */ }

The length of a particular slice (or a number of slices).

The encapsulated length field is guaranteed to be at most the length of each of the slices with the exact same tag. In other words, all indices strictly smaller than this number are safe.

This allows this instance to construct indices that are validated to be able to soundly access the slices without required any particular slice instance. In particular, the construct might happen by a numerical algorithm independent of the slices and across method bounds where the compiler’s optimizer and inline pass is no longer aware of the connection and would otherwise insert another check when the slice is indexed later.

Implementations

impl<T: Tag> Len<T>

pub fn with_tag<NewT>(self, less: LessEq<T, NewT>) -> Len<NewT>

Interpret this with the tag of a set of potentially longer slices.

The proof of inequality was performed in any of the possible constructors that allow the instance of LessEq to exist in the first place.

pub fn get(self) -> usize

Returns the stored length.

pub fn index(self, idx: usize) -> Option<Idx<usize, T>>

Construct an index to a single element.

This method return Some when the index is smaller than the length.

pub fn range(self, from: usize, to: usize) -> Option<Idx<Range<usize>, T>>

Construct an index to a range of element.

This method return Some when the indices are ordered and to does not exceed the length.

pub fn range_from(self, from: usize) -> Option<Idx<RangeFrom<usize>, T>>

Construct an index to a range from an element.

This method return Some when from does not exceed the length.

pub fn range_from_self(self) -> Idx<RangeFrom<usize>, T>

Construct an index to a range starting at this length.

This method might return an index for an empty range.

pub fn range_to(self, to: usize) -> Option<Idx<RangeTo<usize>, T>>

Construct an index to a range up to an element.

This method return Some when to does not exceed the length.

pub fn range_to_self(self) -> Idx<RangeTo<usize>, T>

Construct an index to a range up, exclusive, to this length.

This method might return an index for an empty range.

pub fn range_between(self, other: Self) -> Idx<Range<usize>, T>

Construct an index referring to the unordered range from one element to another.

This method might return an empty range. The order of arguments does not matter.

pub fn range_full(self) -> Idx<RangeFull, T>

Construct an index to all elements.

This method exists mostly for completeness sake. There is no bounds check when accessing a complete slice with ...

pub fn saturating_sub(self, sub: usize) -> Self

Create a smaller length.

pub fn truncate(self, min: usize) -> Self

Bound the length from above.

Trait Implementations

impl<Tag: Clone> Clone for Len<Tag>

fn clone(&self) -> Len<Tag>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Tag> From<NonZeroLen<T>> for Len<T>

fn from(from: NonZeroLen<T>) -> Self

Performs the conversion.

impl<Tag: Copy> Copy for Len<Tag>