Struct Idx 

pub struct Idx<T> { /* private fields */ }

A 32-bit index into a flat table of T.

Idx<T> is Copy, is exactly four bytes, and has a niche, so Option<Idx<T>> is also four bytes. Optional indices are everywhere in a compiler (no successor, no parent, no spill slot) and paying eight bytes for each of them adds up, so the value is stored biased by one over a NonZeroU32. That is where the limit of one below u32::MAX on the largest representable index comes from.

Implementations

impl<T> Idx<T>

pub const MAX: u32

The largest index that can be represented.

pub const fn new(raw: u32) -> Self

Wraps a raw index.

Panics

Panics if raw exceeds Idx::MAX. A translation unit with four billion of anything is not a translation unit we intend to compile, and the alternative to panicking is silently truncating, which is worse.

pub fn from_usize(raw: usize) -> Self

Wraps a usize, which is what indexing a Vec gives back.

Panics

Panics if the value exceeds Idx::MAX.

pub const fn raw(self) -> u32

The underlying u32.

pub const fn index(self) -> usize

The index as a usize, for slicing.

Trait Implementations

impl<T> Clone for Idx<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T> Copy for Idx<T>

impl<T> Debug for Idx<T>

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

Formats the value using the given formatter.

impl<T> Eq for Idx<T>

impl<T> Hash for Idx<T>

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<T> Ord for Idx<T>

fn cmp(&self, other: &Self) -> 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.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl<T> PartialEq for Idx<T>

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

Equality operator ==.

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

Inequality operator !=.

impl<T> PartialOrd for Idx<T>

fn partial_cmp(&self, other: &Self) -> 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.