Struct compact_arena::SmallArena

pub struct SmallArena<'tag, T> { /* fields omitted */ }

A "Small" arena based on a resizable slice (i.e. a Vec) that can be indexed with 32-bit Idx32s. This can help reduce memory overhead when using many pointer-heavy objects on 64-bit systems.

You can obtain an instance of this type by calling mk_arena.

Methods

impl<'tag, T> SmallArena<'tag, T>

pub unsafe fn new(tag: InvariantLifetime<'tag>, capacity: usize) -> Self

create a new SmallArena. Don't do this manually. Use the in_arena macro instead.

Safety

The whole tagged indexing trick relies on the 'tag you give to this constructor. You must never use this value in another arena, lest you might be able to mix up the indices of the two, which could lead to out of bounds access and thus Undefined Behavior!

pub fn try_add(&mut self, item: T) -> Result<Idx32<'tag>, CapacityExceeded<T>>

Add an item to the arena, get an index or CapacityExceeded back.

pub fn add(&mut self, item: T) -> Idx32<'tag>

Add an item to the arena, get an index back.

Trait Implementations

impl<'tag, T> Index<Idx<'tag, u32>> for SmallArena<'tag, T>

type Output = T

The returned type after indexing.

fn index(&self, i: Idx32<'tag>) -> &T

Gets an immutable reference to the value at this index.

impl<'tag, T> IndexMut<Idx<'tag, u32>> for SmallArena<'tag, T>

fn index_mut(&mut self, i: Idx32<'tag>) -> &mut T

Gets a mutable reference to the value at this index.