Struct SlabArena 

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

An arena with O(1) deallocation via a free list.

Freed slots are tracked and reused on the next allocation.

Implementations

impl<T> SlabArena<T>

pub fn new() -> Self

Create a new empty slab arena.

pub fn with_capacity(cap: usize) -> Self

Create a slab arena with the given initial capacity.

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

Allocate a value, reusing a freed slot if available.

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

Free the value at idx, returning it.

Returns None if the slot was already free.

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

Get a reference to the value at idx.

Returns None if the slot is free.

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

Get a mutable reference to the value at idx.

pub fn len(&self) -> usize

Number of live (non-free) slots.

pub fn capacity_slots(&self) -> usize

Total number of slots (including free ones).

pub fn is_empty(&self) -> bool

Returns true if there are no live values.

pub fn free_count(&self) -> usize

Number of slots on the free list.

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

Iterate over all live (non-free) (index, value) pairs.

Trait Implementations

impl<T: Debug> Debug for SlabArena<T>

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

Formats the value using the given formatter.

impl<T> Default for SlabArena<T>

fn default() -> Self

Returns the “default value” for a type.