Contribution guide | Apache v2 license
Enum-centric data structures for Rust.
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.
use enum_collections::{EnumMap, Enumerated};
#[derive(Enumerated)]
enum Letter {
A,
B,
}
assert_eq!(Letter::VARIANTS.len(), 2); // VARIANTS provided by this crate
let mut map: EnumMap<Letter, u8> = EnumMap::new();
map.insert(Letter::A, 42);
assert_eq!(Some(&42u8), map.get(Letter::A));
map.remove(Letter::A);
assert_eq!(None, map.get(Letter::A));
Using Index
and IndexMut
syntactic sugar.
use enum_collections::{EnumMap, Enumerated};
#[derive(Enumerated)]
enum Letter {
A,
B,
}
let mut map: EnumMap<Letter, u8> = EnumMap::new();
map[Letter::A] = Some(42);
assert_eq!(Some(42u8), map[Letter::A]);
assert_eq!(Some(&42u8), map[Letter::A].as_ref());
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.
use enum_collections::{EnumTable, Enumerated};
#[derive(Enumerated)]
enum Letter {
A,
B,
}
assert_eq!(Letter::VARIANTS.len(), 2); // VARIANTS provided by this crate
let mut map: EnumTable<Letter, u8> = EnumTable::new();
map[Letter::A] = 42;
assert_eq!(42u8, map[Letter::A]);
assert_eq!(u8::default(), map[Letter::B]);
Portions of functionality are feature-flagged, but enabled by default. This is to allow turning this functionality off when not needed, e.g. Debug
and Eq
implementations.
See docs.rs for details.
There are single-threaded benchmarks for the get
, insert
and remove
operations in enum-collections/benches. Invoke cargo bench
to run them.
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]
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]