Crate typed_arena

The arena, a fast but limited type of allocator.

A fast (but limited) allocation arena for values of a single type.

Allocated objects are destroyed all at once, when the arena itself is destroyed. There is no deallocation of individual objects while the arena itself is still alive. The flipside is that allocation is fast: typically just a vector push.

There is also a method into_vec() to recover ownership of allocated objects when the arena is no longer required, instead of destroying everything.

Example

use typed_arena::Arena;

struct Monster {
    level: u32,
}

let monsters = Arena::new();

let vegeta = monsters.alloc(Monster { level: 9001 });
assert!(vegeta.level > 9000);

Safe Cycles

All allocated objects get the same lifetime, so you can safely create cycles between them. This can be useful for certain data structures, such as graphs and trees with parent pointers.

use std::cell::Cell;
use typed_arena::Arena;

struct CycleParticipant<'a> {
    other: Cell<Option<&'a CycleParticipant<'a>>>,
}

let arena = Arena::new();

let a = arena.alloc(CycleParticipant { other: Cell::new(None) });
let b = arena.alloc(CycleParticipant { other: Cell::new(None) });

a.other.set(Some(b));
b.other.set(Some(a));

Structs

Arena	An arena of objects of type T.
IterMut	Mutable arena iterator.