Struct LruMap 

pub struct LruMap<K, V, S = DefaultHashBuilder> { /* private fields */ }

A hash map holding at most max_length entries that evicts the least recently used entry.

get and the insert methods mark an entry as most recently used, the peek methods don’t.

Implementations

impl<K, V> LruMap<K, V>

pub fn new(max_length: u32) -> Self

Creates an empty map that holds at most max_length entries, using the default hasher. Does not allocate.

impl<K, V, S> LruMap<K, V, S>

pub const fn with_hasher(max_length: u32, hasher: S) -> Self

Creates an empty map that holds at most max_length entries, using hasher to hash keys. Does not allocate.

pub const fn max_length(&self) -> u32

Returns the maximum number of entries.

pub const fn len(&self) -> usize

Returns the number of entries.

pub const fn is_empty(&self) -> bool

Returns true if the map holds no entries.

pub fn memory_usage(&self) -> usize

Returns the number of heap bytes allocated by the map, excluding heap memory owned by keys and values.

pub fn peek_oldest(&self) -> Option<(&K, &V)>

Returns the least recently used entry without changing its position.

pub fn peek_newest(&self) -> Option<(&K, &V)>

Returns the most recently used entry without changing its position.

pub const fn iter(&self) -> Iter<'_, K, V, S>

Iterates from the most to the least recently used entry.

pub fn clear(&mut self)

Removes all entries, keeping the allocated memory.

impl<K, V, S> LruMap<K, V, S>

where K: Hash + Eq, S: BuildHasher,

pub fn get<Q>(&mut self, key: &Q) -> Option<&mut V>

where K: Borrow<Q>, Q: Hash + Eq + ?Sized,

Returns the value for key and marks it as the most recently used.

pub fn peek<Q>(&self, key: &Q) -> Option<&V>

where K: Borrow<Q>, Q: Hash + Eq + ?Sized,

Returns the value for key without changing its position.

pub fn peek_mut<Q>(&mut self, key: &Q) -> Option<&mut V>

where K: Borrow<Q>, Q: Hash + Eq + ?Sized,

Returns a mutable reference to the value for key without changing its position.

pub fn contains<Q>(&self, key: &Q) -> bool

where K: Borrow<Q>, Q: Hash + Eq + ?Sized,

Returns true if the map contains key, without changing its position.

pub fn insert(&mut self, key: K, value: V) -> Option<(K, V)>

Inserts value for key, or replaces the current value, and marks key as the most recently used.

Returns the least recently used entry if it was evicted to make room. If max_length is zero, nothing is stored and the given entry is returned instead.

pub fn get_or_insert(&mut self, key: K, f: impl FnOnce() -> V) -> Option<&mut V>

Returns the value for key and marks it as the most recently used, first inserting the value returned by f if key is absent.

Returns None only if max_length is zero.

pub fn remove<Q>(&mut self, key: &Q) -> Option<V>

where K: Borrow<Q>, Q: Hash + Eq + ?Sized,

Removes key and returns its value.

pub fn pop_oldest(&mut self) -> Option<(K, V)>

Removes and returns the least recently used entry.

Trait Implementations

impl<K, V, S> Debug for LruMap<K, V, S>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<K, V, S: Default> Default for LruMap<K, V, S>

fn default() -> Self

Returns an empty map with max_length zero, which stores nothing.

impl<K, V, S> Drop for LruMap<K, V, S>

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics #130494)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl<'a, K, V, S> IntoIterator for &'a LruMap<K, V, S>

type Item = (&'a K, &'a V)

The type of the elements being iterated over.

type IntoIter = Iter<'a, K, V, S>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

Layout

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.