#no-std #allocator #vec #queue

no-std coca

Data structures with constant capacity

2 unstable releases

0.2.0 Dec 28, 2020
0.1.0 Dec 3, 2020

#731 in Data structures

Zlib OR Apache-2.0


coca - Data Structures with Constant Capacity

Crates.io Documentation

Allocation-free data structures that make do with the memory they're given.

This makes their temporal performance more consistent, and the memory footprint dead-simple to predict - but it also means insertions can easily fail, so you'll need proof you can't break the limit, or a graceful recovery path, which is good practice in memory-constrained environments anyway.

Currently, four main components are provided:

  • Arena, a bump-/stack-allocator, plus Box<'a, T> the corresponding smart pointer,
  • Vec, a bounded, growable array, generic over not only the element type, but also the underlying storage type (as in this recent proposal) and the index type (inspired by typed-index-collections),
  • BinaryHeap, a priority queue implemented on top of Vec,
  • Deque, a double-ended queue implemented with a ring buffer.

This crate is still in early development! Currently on the roadmap (in no particular order):

  • A slotmap-style pool-allocator, as well as a dense pool optimized for iteration speed, as opposed to random access,
  • ordered and unordered map and set implementations.

Constructive Feedback and Contributions Welcome!

Getting Started

To add coca as a dependency, add this to your project's Cargo.toml:

coca = "0.2"

Optional Features

  • alloc: By default, coca is no_std compatible; this feature flag enables some trait implementations for conveniently working with heap-allocated storage.
  • nightly: If you're working with the nightly rust toolchain, you can enable this feature to get access to InlineStorage and ArrayVec, both of which are implemented using the nightly-only min_const_generics feature; this flag will eventually be removed.
  • profile: Enables memory profiling in arenas; see the module-level documentation for details.


Licensed under either Apache License, Version 2.0 or Zlib license at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate 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