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 enumcollections::{enumcollections, EnumMap, Enumerated}; #[enum_collections] 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 enumcollections::{enumcollections, EnumMap, Enumerated}; #[enum_collections] 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 enumcollections::{enumcollections, EnumTable, Enumerated}; #[enum_collections] 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 enumcollections::{enumcollections, EnumTable, Enumerated}; #[enum_collections] 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: [947.20 ps 947.83 ps 948.52 ps] est ~14,7x faster std::collections::HashMap insert time: [13.938 ns 13.964 ns 13.994 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 IndexMut insert time: [746.66 ps 747.67 ps 748.79 ps] est ~0.943x speed Crate Enum-Map insert time: [704.81 ps 705.35 ps 705.92 ps] est ~1.057x faster ```