Enum Collections for Rust

Enum-centric data structures for Rust.

Usage

EnumMap

EnumMap is a special case of a Hash Map, with better computational complexity guarantees and overall performance. Can differentiante between a missing (Option::None) and set (Option::Some) value.

Abstracts away the need to handle [Option] on insert/remove operations. It marginally is faster to initialize than EnumTable, because Default value needn't be cloned for each field.

Using get and insert functions.

```rust use enum_collections::{EnumMap, Enumerated}; #[derive(Enumerated)] enum Letter { A, B, }

let mut map: EnumMap = EnumMap::new(); map.insert(Letter::A, 42); asserteq!(Some(&42u8), map.get(Letter::A)); map.remove(Letter::A); asserteq!(None, map.get(Letter::A)); ```

Using Index and IndexMut syntactic sugar. ```rust use enum_collections::{EnumMap, Enumerated}; #[derive(Enumerated)] enum Letter { A, B, }

let mut map: EnumMap = EnumMap::new(); map[Letter::A] = Some(42); asserteq!(Some(42u8), map[Letter::A]); asserteq!(Some(&42u8), map[Letter::A].as_ref()); ```

EnumTable

EnumTable is a special case of a Hash Map, with better computational complexity guarantees and overall performance. Initialized with default values, can NOT differentiate between missing values and values actually set.

Using Index and IndexMut syntactic sugar.

```rust use enum_collections::{EnumTable, Enumerated}; #[derive(Enumerated)] enum Letter { A, B, }

let mut map: EnumTable = EnumTable::new(); map[Letter::A] = 42; asserteq!(42u8, map[Letter::A]); asserteq!(u8::default(), map[Letter::B]); ```

Using get and insert functions.

```rust use enum_collections::{EnumTable, Enumerated}; #[derive(Enumerated)] enum Letter { A, B, }

let mut map: EnumTable = EnumTable::new(); map.insert(Letter::A, 42); asserteq!(&42u8, map.get(Letter::A)); asserteq!(&u8::default(), map.get(Letter::B)); ```

Benchmarks

There are single-threaded benchmarks for the get, insert and remove operations in enum-collections/benches. Invoke cargo bench to run them.

EnumMap

``` NAME lower bound | est | upper bound EnumMap get time: [635.02 ps 635.52 ps 636.06 ps] est ~22x faster std::collections::HashMap get time: [13.971 ns 13.986 ns 14.002 ns]

EnumMap insert time: [890.74 ps 892.13 ps 893.66 ps] est ~15,57x faster std::collections::HashMap insert time: [13.889 ns 13.895 ns 13.901 ns]

EnumMap remove time: [481.07 ps 481.79 ps 482.53 ps] est ~28,55x faster std::collections::HashMap remove time: [13.704 ns 13.737 ns 13.771 ns] ```

EnumTable

``` NAME lower bound | est | upper bound EnumTable Index get time: [460.22 ps 460.81 ps 461.41 ps] est ~1.113x faster Crate Enum-Map Index get time: [512.16 ps 512.62 ps 513.13 ps]

EnumTable insert time: [670.83 ps 671.43 ps 672.06 ps] est. ~1,06x faster Crate Enum-Map insert time: [715.68 ps 716.34 ps 717.04 ps] ```