#heap #fixed-size #queue #priority #storage #priority-queue


A fixed-size heap structure with manually provided stateful comparison function

2 unstable releases

0.2.0 Nov 7, 2022
0.1.0 Oct 31, 2022

#437 in Memory management


587 lines


A Rust data-structure like BinaryHeap except fixed-size, backed by an array, with manually provided comparison functions which may depend on external data-structures. This permits having a heap of keys ordered by the values associated with them in another data-structure. Please consult the documentation for more information.

The minimum required Rust version for fixed_heap is 1.60.0. To start using fixed_heap add the following to your Cargo.toml:

fixed_heap = "0.2"

For additional performance, enable unstable feature on nightly with

fixed_heap = { version = "0.2", features = ["unstable"] }


A short example:

use fixed_heap::FixedHeap;
let mut heap: FixedHeap<i32, 16> = FixedHeap::new();
let comparer = |a: &i32, b: &i32, _: &()| a > b;
heap.pop(&comparer, &());

With keys into another struct:

use fixed_heap::FixedHeap;
let mut heap: FixedHeap<usize, 16> = FixedHeap::new();
let comparer = |a: &usize, b: &usize, state: &[i32; 4]| state[*a] > state[*b];
let state = [1, 3, 1, 2];
heap.push(0, &comparer, &state);


This crate uses unsafe code for performance. It has been extensively fuzz tested with miri to ensure it behaves correctly.


fixed_heap is dual-licensed under either:

at your option.

Your contributions

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

No runtime deps