Struct Arena 

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

A typed arena for storing values contiguously.

Values are never moved once allocated, so references remain valid for the lifetime of the arena.

Implementations

impl<T> Arena<T>

pub fn new() -> Self

Create a new empty arena.

pub fn with_capacity(capacity: usize) -> Self

Create a new arena with the specified capacity.

pub fn alloc(&mut self, value: T) -> Idx<T>

Allocate a value in the arena and return its index.

pub fn alloc_many(&mut self, values: impl IntoIterator<Item = T>) -> IdxRange<T>

Allocate multiple values at once, returning the index range.

pub fn get(&self, idx: Idx<T>) -> &T

Get a reference to the value at the given index.

Panics

Panics if the index is out of bounds (in debug mode).

pub fn get_mut(&mut self, idx: Idx<T>) -> &mut T

Get a mutable reference to the value at the given index.

pub fn get_range(&self, range: IdxRange<T>) -> &[T]

Get a slice of values for the given range.

pub fn len(&self) -> usize

Get the number of values in the arena.

pub fn is_empty(&self) -> bool

Check if the arena is empty.

pub fn next_idx(&self) -> Idx<T>

Get the index that would be assigned to the next allocation.

pub fn iter_indexed(&self) -> impl Iterator<Item = (Idx<T>, &T)>

Iterate over all (index, value) pairs.

pub fn iter(&self) -> impl Iterator<Item = &T>

Iterate over all values.

pub fn stats(&self) -> ArenaStats

Collect the current size statistics.

pub fn shrink_to_fit(&mut self)

Shrink the arena’s backing storage to fit.

pub fn clear(&mut self)

Reset the arena, dropping all values.

Trait Implementations

impl<T: Debug> Debug for Arena<T>

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

Formats the value using the given formatter.

impl<T> Default for Arena<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T> Index<Idx<T>> for Arena<T>

type Output = T

The returned type after indexing.

fn index(&self, idx: Idx<T>) -> &T

Performs the indexing (container[index]) operation.