mirror of
https://github.com/rust-embedded/heapless.git
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112 lines
3.8 KiB
Rust
112 lines
3.8 KiB
Rust
//! `static` friendly data structures that don't require dynamic memory allocation
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//!
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//! The core principle behind `heapless` is that its data structures are backed by a *static* memory
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//! allocation. For example, you can think of `heapless::Vec` as an alternative version of
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//! `std::Vec` with fixed capacity and that can't be re-allocated on the fly (e.g. via `push`).
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//!
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//! All `heapless` data structures store their memory allocation *inline* and specify their capacity
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//! via their type parameter `N`. This means that you can instantiate a `heapless` data structure on
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//! the stack, in a `static` variable, or even in the heap.
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//!
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//! ```
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//! use heapless::Vec; // fixed capacity `std::Vec`
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//!
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//! // on the stack
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//! let mut xs: Vec<u8, 8> = Vec::new(); // can hold up to 8 elements
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//! xs.push(42).unwrap();
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//! assert_eq!(xs.pop(), Some(42));
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//!
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//! // in a `static` variable
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//! static mut XS: Vec<u8, 8> = Vec::new();
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//!
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//! let xs = unsafe { &mut XS };
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//!
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//! xs.push(42);
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//! assert_eq!(xs.pop(), Some(42));
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//!
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//! // in the heap (though kind of pointless because no reallocation)
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//! let mut ys: Box<Vec<u8, 8>> = Box::new(Vec::new());
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//! ys.push(42).unwrap();
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//! assert_eq!(ys.pop(), Some(42));
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//! ```
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//!
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//! Because they have fixed capacity `heapless` data structures don't implicitly reallocate. This
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//! means that operations like `heapless::Vec.push` are *truly* constant time rather than amortized
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//! constant time with potentially unbounded (depends on the allocator) worst case execution time
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//! (which is bad / unacceptable for hard real time applications).
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//!
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//! `heapless` data structures don't use a memory allocator which means no risk of an uncatchable
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//! Out Of Memory (OOM) condition while performing operations on them. It's certainly possible to
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//! run out of capacity while growing `heapless` data structures, but the API lets you handle this
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//! possibility by returning a `Result` on operations that may exhaust the capacity of the data
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//! structure.
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//!
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//! List of currently implemented data structures:
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//!
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//! - [`BinaryHeap`](binary_heap/struct.BinaryHeap.html) -- priority queue
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//! - [`IndexMap`](struct.IndexMap.html) -- hash table
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//! - [`IndexSet`](struct.IndexSet.html) -- hash set
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//! - [`LinearMap`](struct.LinearMap.html)
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//! - [`Pool`](pool/struct.Pool.html) -- lock-free memory pool
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//! - [`String`](struct.String.html)
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//! - [`Vec`](struct.Vec.html)
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//! - [`mpmc::Q*`](mpmc/index.html) -- multiple producer multiple consumer lock-free queue
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//! - [`spsc::Queue`](spsc/struct.Queue.html) -- single producer single consumer lock-free queue
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//!
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//! # Optional Features
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//!
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//! The `heapless` crate provides the following optional Cargo features:
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//!
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//! - `ufmt-impl`: Implement [`ufmt_write::uWrite`] for `String<N>` and `Vec<u8, N>`
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//!
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//! [`ufmt_write::uWrite`]: https://docs.rs/ufmt-write/
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//!
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//! # Minimum Supported Rust Version (MSRV)
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//!
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//! This crate is guaranteed to compile on stable Rust 1.51 and up with its default set of features.
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//! It *might* compile on older versions but that may change in any new patch release.
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#![cfg_attr(not(test), no_std)]
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#![deny(missing_docs)]
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#![deny(rust_2018_compatibility)]
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#![deny(rust_2018_idioms)]
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#![deny(warnings)]
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#![deny(const_err)]
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pub use binary_heap::BinaryHeap;
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pub use deque::Deque;
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pub use histbuf::HistoryBuffer;
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pub use indexmap::{Bucket, FnvIndexMap, IndexMap, Pos};
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pub use indexset::{FnvIndexSet, IndexSet};
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pub use linear_map::LinearMap;
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pub use string::String;
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pub use vec::Vec;
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mod deque;
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mod histbuf;
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mod indexmap;
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mod indexset;
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mod linear_map;
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mod string;
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mod vec;
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#[cfg(feature = "serde")]
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mod de;
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#[cfg(feature = "serde")]
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mod ser;
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pub mod binary_heap;
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#[cfg(feature = "defmt-impl")]
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mod defmt;
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#[cfg(all(has_cas, feature = "cas"))]
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pub mod mpmc;
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#[cfg(all(has_cas, feature = "cas"))]
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pub mod pool;
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#[cfg(has_atomics)]
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pub mod spsc;
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#[cfg(feature = "ufmt-impl")]
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mod ufmt;
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mod sealed;
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