`acid_alloc`

Bare-metal allocators.

This crate provides allocators that are suitable for use on bare metal or with OS allocation facilities like mmap(2)/brk(2).

The following allocator types are available:

Buddy, a binary-buddy allocator. O(log₂levels) worst-case allocation and deallocation. Supports splitting and coalescing blocks by powers of 2. Good choice for periodic medium-to-large allocations.
Bump, a bump allocator. O(1) allocation. Extremely fast to allocate and flexible in terms of allocation layout, but unable to deallocate individual items. Good choice for allocations that will never be deallocated or that will be deallocated en masse.
Slab, a slab allocator. O(1) allocation and deallocation. All allocated blocks are the same size, making this allocator a good choice when allocating many similarly-sized objects.

Features

All allocators provided by this crate are available in a #![no_std], #![cfg(no_global_oom_handling)] environment. Additional functionality is available when enabling feature flags:

Flag	Default?	Requires nightly?	Description
`sptr`	Yes	No	Uses the `sptr` polyfill for Strict Provenance.
`unstable`	No	Yes	Exposes constructors for allocators backed by implementors of the unstable `Allocator` trait, and enables the internal use of nightly-only Rust features. Obviates `sptr`.
`alloc`	No	No	Exposes constructors for allocators backed by the global allocator.

Acknowledgments

This crate includes stable-compatible polyfills for a number of unstable standard-library APIs whose implementations are reproduced verbatim here. These features are listed below along with their authors and/or maintainers:

alloc_layout_extra, by [Amanieu d'Antras]
int_log, by [Yoshua Wuyts]
strict_provenance, by [Aria Beingessner (Gankra)]

This crate also depends on [sptr] (also authored by Gankra) to reproduce strict provenance for normal pointers on stable Rust.

If I've misattributed any of this work, or a contributor to these features is missing, please open an issue!

License

Licensed under either of

Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

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.