Arena allocator - Rust

Fixed-capacity bump-pointer arena with reset() for per-request reuse. Allocate is a single cursor bump; reset is constant-time. Auto-grow is opt-in via the growable feature.

Part of the submillisecond.com cookbook. Zero external dependencies; std only.

Install

[dependencies]
subms-arena-allocator = "0.5"

Opt-in features layer focused capability over the fixed-capacity base: typed, growable, stats, aligned, freelist.

Quickstart

cargo test --release
cargo run --example demo

Public API

pub struct Bump
pub fn new() -> Self
pub fn with_capacity(capacity_bytes: usize) -> Self
pub fn alloc_copy<T: Copy>(&mut self, value: T) -> &mut T
pub fn try_alloc_copy<T: Copy>(&mut self, value: T) -> Option<&mut T>
pub fn alloc_raw(&mut self, layout: Layout) -> *mut u8
pub fn try_alloc_raw(&mut self, layout: Layout) -> Option<*mut u8>
pub fn reset(&mut self)
pub fn used(&self) -> usize
pub fn capacity(&self) -> usize
pub fn total_capacity(&self) -> usize (alias for capacity)

Files

src/lib.rs - implementation.
tests/ - integration tests; correctness, edge cases, property/stress.
examples/demo.rs - stdout walkthrough.
examples/perf_main.rs - bench entry (behind the harness feature).

License