Struct Arena

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

Yet another index-based arena.

Implementations

impl<T> Arena<T>

pub const fn new() -> Arena<T>

Creates a new empty arena.

let arena: la_arena::Arena<i32> = la_arena::Arena::new();
assert!(arena.is_empty());

pub fn with_capacity(capacity: usize) -> Arena<T>

Create a new empty arena with specific capacity.

let arena: la_arena::Arena<i32> = la_arena::Arena::with_capacity(42);
assert!(arena.is_empty());

pub fn clear(&mut self)

Empties the arena, removing all contained values.

let mut arena = la_arena::Arena::new();

arena.alloc(1);
arena.alloc(2);
arena.alloc(3);
assert_eq!(arena.len(), 3);

arena.clear();
assert!(arena.is_empty());

pub fn len(&self) -> usize

Returns the length of the arena.

let mut arena = la_arena::Arena::new();
assert_eq!(arena.len(), 0);

arena.alloc("foo");
assert_eq!(arena.len(), 1);

arena.alloc("bar");
assert_eq!(arena.len(), 2);

arena.alloc("baz");
assert_eq!(arena.len(), 3);

pub fn is_empty(&self) -> bool

Returns whether the arena contains no elements.

let mut arena = la_arena::Arena::new();
assert!(arena.is_empty());

arena.alloc(0.5);
assert!(!arena.is_empty());

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

Allocates a new value on the arena, returning the value’s index.

let mut arena = la_arena::Arena::new();
let idx = arena.alloc(50);

assert_eq!(arena[idx], 50);

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

Densely allocates multiple values, returning the values’ index range.

let mut arena = la_arena::Arena::new();
let range = arena.alloc_many(0..4);

assert_eq!(arena[range], [0, 1, 2, 3]);

pub fn iter( &self, ) -> impl ExactSizeIterator<Item = (Idx<T>, &T)> + DoubleEndedIterator + Clone

Returns an iterator over the arena’s elements.

let mut arena = la_arena::Arena::new();
let idx1 = arena.alloc(20);
let idx2 = arena.alloc(40);
let idx3 = arena.alloc(60);

let mut iterator = arena.iter();
assert_eq!(iterator.next(), Some((idx1, &20)));
assert_eq!(iterator.next(), Some((idx2, &40)));
assert_eq!(iterator.next(), Some((idx3, &60)));

pub fn iter_mut( &mut self, ) -> impl ExactSizeIterator<Item = (Idx<T>, &mut T)> + DoubleEndedIterator

Returns an iterator over the arena’s mutable elements.

let mut arena = la_arena::Arena::new();
let idx1 = arena.alloc(20);

assert_eq!(arena[idx1], 20);

let mut iterator = arena.iter_mut();
*iterator.next().unwrap().1 = 10;
drop(iterator);

assert_eq!(arena[idx1], 10);

pub fn values(&self) -> impl ExactSizeIterator<Item = &T> + DoubleEndedIterator

Returns an iterator over the arena’s values.

let mut arena = la_arena::Arena::new();
let idx1 = arena.alloc(20);
let idx2 = arena.alloc(40);
let idx3 = arena.alloc(60);

let mut iterator = arena.values();
assert_eq!(iterator.next(), Some(&20));
assert_eq!(iterator.next(), Some(&40));
assert_eq!(iterator.next(), Some(&60));

pub fn values_mut( &mut self, ) -> impl ExactSizeIterator<Item = &mut T> + DoubleEndedIterator

Returns an iterator over the arena’s mutable values.

let mut arena = la_arena::Arena::new();
let idx1 = arena.alloc(20);

assert_eq!(arena[idx1], 20);

let mut iterator = arena.values_mut();
*iterator.next().unwrap() = 10;
drop(iterator);

assert_eq!(arena[idx1], 10);

pub fn shrink_to_fit(&mut self)

Reallocates the arena to make it take up as little space as possible.

Trait Implementations

impl<T> AsMut<[T]> for Arena<T>

fn as_mut(&mut self) -> &mut [T]

Converts this type into a mutable reference of the (usually inferred) input type.

impl<T: Clone> Clone for Arena<T>

fn clone(&self) -> Arena<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

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

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

Formats the value using the given formatter.

impl<T> Default for Arena<T>

fn default() -> Arena<T>

Returns the “default value” for a type.

impl<T> Extend<T> for Arena<T>

fn extend<II: IntoIterator<Item = T>>(&mut self, iter: II)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

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

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

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

Reserves capacity in a collection for the given number of additional elements.

impl<T> FromIterator<T> for Arena<T>

fn from_iter<I>(iter: I) -> Self

where I: IntoIterator<Item = T>,

Creates a value from an iterator.

impl<T: Hash> Hash for Arena<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> 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.

impl<T> Index<IdxRange<T>> for Arena<T>

type Output = [T]

The returned type after indexing.

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

Performs the indexing (container[index]) operation.

impl<T> IndexMut<Idx<T>> for Arena<T>

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

Performs the mutable indexing (container[index]) operation.

impl<T> IntoIterator for Arena<T>

type Item = (Idx<T>, T)

The type of the elements being iterated over.

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<T: PartialEq> PartialEq for Arena<T>

fn eq(&self, other: &Arena<T>) -> 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<T: Eq> Eq for Arena<T>

impl<T> StructuralPartialEq for Arena<T>