Struct Arena

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

An arena allocator with a given index and entity type.

For performance reasons the arena cannot deallocate single entities.

Implementations

impl<Idx, T> Arena<Idx, T>

pub fn new() -> Self

Creates a new empty entity arena.

pub fn len(&self) -> usize

Returns the allocated number of entities.

pub fn is_empty(&self) -> bool

Returns true if the arena has not yet allocated entities.

pub fn clear(&mut self)

Clears all entities from the arena.

pub fn iter(&self) -> Iter<'_, Idx, T>

Returns an iterator over the shared reference of the arena entities.

pub fn iter_mut(&mut self) -> IterMut<'_, Idx, T>

Returns an iterator over the exclusive reference of the arena entities.

impl<Idx, T> Arena<Idx, T>

where Idx: ArenaIndex,

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

Allocates a new entity and returns its index.

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

Returns a shared reference to the entity at the given index if any.

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

Returns an exclusive reference to the entity at the given index if any.

pub fn get_pair_mut(&mut self, fst: Idx, snd: Idx) -> Option<(&mut T, &mut T)>

Returns an exclusive reference to the pair of entities at the given indices if any.

Returns None if fst and snd refer to the same entity. Returns None if either fst or snd is invalid for this Arena.

Trait Implementations

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

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

Formats the value using the given formatter.

impl<Idx, T> Default for Arena<Idx, T>

fn default() -> Self

Returns the “default value” for a type.

impl<Idx, T> FromIterator<T> for Arena<Idx, T>

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

where I: IntoIterator<Item = T>,

Creates a value from an iterator.

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

where Idx: ArenaIndex,

type Output = T

The returned type after indexing.

fn index(&self, index: Idx) -> &Self::Output

Performs the indexing (container[index]) operation.

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

where Idx: ArenaIndex,

fn index_mut(&mut self, index: Idx) -> &mut Self::Output

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

impl<'a, Idx, T> IntoIterator for &'a Arena<Idx, T>

where Idx: ArenaIndex,

type Item = (Idx, &'a T)

The type of the elements being iterated over.

type IntoIter = Iter<'a, Idx, T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'a, Idx, T> IntoIterator for &'a mut Arena<Idx, T>

where Idx: ArenaIndex,

type Item = (Idx, &'a mut T)

The type of the elements being iterated over.

type IntoIter = IterMut<'a, Idx, T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<Idx, T> PartialEq for Arena<Idx, T>

where T: PartialEq,

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

where T: Eq,

impl<Idx, T> Send for Arena<Idx, T>

where T: Send,

Arena does not store Idx therefore it is Send without its bound.

impl<Idx, T> Sync for Arena<Idx, T>

where T: Send,

Arena does not store Idx therefore it is Sync without its bound.