Struct ArenaHashMap 

pub struct ArenaHashMap { /* private fields */ }

Customized HashMap with &[u8] keys

Its main particularity is that rather than storing its keys in the heap, keys are stored in a memory arena inline with the values.

The quirky API has the benefit of avoiding the computation of the hash of the key twice, or copying the key as long as there is no insert.

Implementations

impl ArenaHashMap

pub fn new(table_size: usize) -> ArenaHashMap

pub fn read<Item: Copy + 'static>(&self, addr: Addr) -> Item

pub fn mem_usage(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn len(&self) -> usize

pub fn iter(&self) -> Iter<'_>

pub fn mutate_or_create<V, TMutator>( &mut self, key: &[u8], updater: TMutator, ) -> UnorderedId

where V: Copy + 'static, TMutator: FnMut(Option<V>) -> V,

update create a new entry for a given key if it does not exist or updates the existing entry.

The actual logic for this update is define in the updater argument.

If the key is not present, updater will receive None and will be in charge of returning a default value. If the key already as an associated value, then it will be passed Some(previous_value).