# vecmap-rs

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A vector-based ordered map and set implementation with zero dependencies and
support for `#![no_std]`.

Map keys are not required to be hashable and do not need to form a total order.
Therefore, [`VecMap<K, V>`](https://docs.rs/vecmap-rs/latest/vecmap/map/struct.VecMap.html)
and [`VecSet<T>`](https://docs.rs/vecmap-rs/latest/vecmap/set/struct.VecSet.html)
can be used with key types which neither implement
[`Hash`](https://doc.rust-lang.org/core/hash/trait.Hash.html) nor
[`Ord`](https://doc.rust-lang.org/core/cmp/trait.Ord.html).

Since vecmap-rs is a [`Vec<(K, V)>`](https://doc.rust-lang.org/alloc/vec/struct.Vec.html)
under the hood, worst case lookup and insertion performance is `O(n)` and
scales with the number of map entries. Thus, its main use case are small
collections with unhashable keys.

For key types that implement `Hash` and `Ord` consider using a map or set
implementation with better performance such as
[`HashMap`](https://doc.rust-lang.org/std/collections/struct.HashMap.html)/[`HashSet`](https://doc.rust-lang.org/std/collections/struct.HashSet.html)
and
[`BTreeMap`](https://doc.rust-lang.org/std/collections/struct.BTreeMap.html)/[`BTreeSet`](https://doc.rust-lang.org/std/collections/struct.BTreeSet.html)
from the standard library or popular alternatives like
[`IndexMap`](https://docs.rs/indexmap/latest/indexmap/map/struct.IndexMap.html)/[`IndexSet`](https://docs.rs/indexmap/latest/indexmap/set/struct.IndexSet.html).

## Cargo features

The following features are available:

* `serde`: Provides [`Serialize`](https://docs.rs/serde/latest/serde/ser/trait.Serialize.html)
  and [`Deserialize`](https://docs.rs/serde/latest/serde/de/trait.Deserialize.html)
  implementations for `VecMap` and `VecSet`. This feature is disabled by
  default. Enabling it will pull in `serde` as a dependency.

## License

The source code of vecmap-rs is licensed under either of [Apache License,
Version 2.0](LICENSE-APACHE.md) or [MIT license](LICENSE-MIT) at your option.