Struct NonMaxUsize

pub struct NonMaxUsize(/* private fields */);

A usize that can never be usize::MAX.

This is similar to core::num::NonZeroUsize, but instead of not permitting a zero value, this does not permit a max value.

This is useful in certain contexts where one wants to optimize the memory usage of things that contain match offsets. Namely, since Rust slices are guaranteed to never have a length exceeding isize::MAX, we can use usize::MAX as a sentinel to indicate that no match was found. Indeed, types like Option<NonMaxUsize> have exactly the same size in memory as a usize.

This type is defined to be repr(transparent) for core::num::NonZeroUsize, which is in turn defined to be repr(transparent) for usize.

Implementations

impl NonMaxUsize

pub fn new(value: usize) -> Option<NonMaxUsize>

Create a new NonMaxUsize from the given value.

This returns None only when the given value is equal to usize::MAX.

pub fn get(self) -> usize

Return the underlying usize value. The returned value is guaranteed to not equal usize::MAX.

Trait Implementations

impl Clone for NonMaxUsize

fn clone(&self) -> NonMaxUsize

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for NonMaxUsize

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

Formats the value using the given formatter.

impl Hash for NonMaxUsize

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

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 Ord for NonMaxUsize

fn cmp(&self, other: &NonMaxUsize) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for NonMaxUsize

fn eq(&self, other: &NonMaxUsize) -> 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 PartialOrd for NonMaxUsize

fn partial_cmp(&self, other: &NonMaxUsize) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for NonMaxUsize

impl Eq for NonMaxUsize

impl StructuralPartialEq for NonMaxUsize

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 8 bytes