Struct HashMap 

pub struct HashMap<K, V, CM = SmallCollection, H = BridgeHasher> { /* private fields */ }

A general-purpose map implemented using a hash table.

This type is an implementation detail of the `frozen_collections` crate. This API is therefore not stable and may change at any time. Please do not use this type directly, and instead use the public API provided by the `frozen_collections` crate.

A frozen collection differs from the traditional Rust collections, such as [`HashMap`](std::collections::HashMap) and [`HashSet`](std::collections::HashSet) types in three key ways. First, creating a frozen collection performs an analysis over the input data to determine the best implementation strategy. Depending on the situation, this analysis is performed at build time or runtime, and it can take a relatively long time when a collection is very large. Second, once created, the keys in frozen collections are immutable. And third, querying a frozen collection is typically considerably faster, which is the whole point.

This type requires that the keys implement the Eq and Hash traits. This can frequently be achieved by using #[derive(PartialEq, Eq, Hash)]. If you implement these yourself, it is important that the following property holds:

k1 == k2 -> hash(k1) == hash(k2)

In other words, if two keys are equal, their hashes must be equal. Violating this property is a logic error.

It is also a logic error for a key to be modified in such a way that the key’s hash, as determined by the Hash trait, or its equality, as determined by the Eq trait, changes while it is in the collection. This is normally only possible through core::cell::Cell, core::cell::RefCell, global state, I/O, or unsafe code.

The behavior resulting from either logic error can include panics, incorrect results, memory leaks, and non-termination.

Implementations

impl<K, V, CM, H> HashMap<K, V, CM, H>

where CM: CollectionMagnitude,

pub fn with_hasher(entries: Vec<(K, V)>, hasher: H) -> Result<Self, String>

where K: Eq, H: Hasher<K>,

Creates a frozen map.

Errors

Fails if the number of entries in the vector, after deduplication, exceeds the magnitude of the collection as specified by the CM generic argument.

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

where Q: ?Sized + Equivalent<K>, H: Hasher<Q>,

Returns a reference to the value corresponding to the key.

The key may be any borrowed form of the map’s key type.

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

where Q: ?Sized + Equivalent<K>, H: Hasher<Q>,

Returns a mutable reference to the value corresponding to the key.

The key may be any borrowed form of the map’s key type.

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

where Q: ?Sized + Equivalent<K>, H: Hasher<Q>,

Returns the key-value pair corresponding to the supplied key.

This is potentially useful:

• for key types where non-identical keys can be considered equal;

• for getting the &K stored key value from a borrowed &Q lookup key; or

• for getting a reference to a key with the same lifetime as the collection.

• The supplied key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

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

where Q: ?Sized + Equivalent<K>, H: Hasher<Q>,

Returns true if the map contains a value for the specified key.

The key may be any borrowed form of the map’s key type.

pub fn get_disjoint_mut<Q, const N: usize>( &mut self, keys: [&Q; N], ) -> [Option<&mut V>; N]

where Q: ?Sized + Eq + Equivalent<K>, H: Hasher<Q>,

Gets multiple mutable values from the map.

Panics

Panics if the same key is specified multiple times.

pub unsafe fn get_disjoint_unchecked_mut<Q, const N: usize>( &mut self, keys: [&Q; N], ) -> [Option<&mut V>; N]

where Q: ?Sized + Equivalent<K>, H: Hasher<Q>,

Gets multiple mutable values from the map.

Safety

Calling this method with overlapping keys is undefined behavior even if the resulting references are not used.

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

An iterator visiting all entries in arbitrary order.

pub fn iter_mut(&mut self) -> IterMut<'_, K, V>

An iterator producing mutable references to all entries in arbitrary order.

pub fn keys(&self) -> Keys<'_, K, V>

An iterator visiting all keys in arbitrary order.

pub fn into_keys(self) -> IntoKeys<K, V>

A consuming iterator visiting all keys in arbitrary order.

pub fn values(&self) -> Values<'_, K, V>

An iterator visiting all values in arbitrary order.

pub fn values_mut(&mut self) -> ValuesMut<'_, K, V>

An iterator visiting all values mutably in arbitrary order.

pub fn into_values(self) -> IntoValues<K, V>

A consuming iterator visiting all values in arbitrary order.

pub fn len(&self) -> usize

Returns the number of elements in the collection.

pub fn is_empty(&self) -> bool

Returns true if the collection contains no elements.

Trait Implementations

impl<K: Clone, V: Clone, CM: Clone, H: Clone> Clone for HashMap<K, V, CM, H>

fn clone(&self) -> HashMap<K, V, CM, H>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<K, V, CM, H> Debug for HashMap<K, V, CM, H>

where K: Debug, V: Debug, CM: CollectionMagnitude,

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

Formats the value using the given formatter.

impl<K, V, CM, H> Default for HashMap<K, V, CM, H>

where CM: CollectionMagnitude, H: Default,

fn default() -> Self

Returns the “default value” for a type.

impl<Q, K, V, CM, H> Index<&Q> for HashMap<K, V, CM, H>

where Q: ?Sized + Equivalent<K>, CM: CollectionMagnitude, H: Hasher<Q>,

type Output = V

The returned type after indexing.

fn index(&self, index: &Q) -> &Self::Output

Performs the indexing (container[index]) operation.

impl<'a, K, V, CM, H> IntoIterator for &'a HashMap<K, V, CM, H>

where CM: CollectionMagnitude,

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

The type of the elements being iterated over.

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

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'a, K, V, CM, H> IntoIterator for &'a mut HashMap<K, V, CM, H>

where CM: CollectionMagnitude,

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

The type of the elements being iterated over.

type IntoIter = IterMut<'a, K, V>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<K, V, CM, H> IntoIterator for HashMap<K, V, CM, H>

where CM: CollectionMagnitude,

type Item = (K, V)

The type of the elements being iterated over.

type IntoIter = IntoIter<K, V>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<K, V, CM, H> Len for HashMap<K, V, CM, H>

where CM: CollectionMagnitude,

fn len(&self) -> usize

Returns the number of elements in the collection.

fn is_empty(&self) -> bool

Returns true if the collection contains no elements.

impl<K, V, Q, CM, H> MapExtras<K, V, Q> for HashMap<K, V, CM, H>

where CM: CollectionMagnitude, Q: ?Sized + Equivalent<K>, H: Hasher<Q>,

fn get_key_value(&self, key: &Q) -> Option<(&K, &V)>

Returns the key-value pair corresponding to the supplied key.

fn get_disjoint_mut<const N: usize>( &mut self, keys: [&Q; N], ) -> [Option<&mut V>; N]

where Q: Eq,

Gets multiple mutable values from the map.

unsafe fn get_disjoint_unchecked_mut<const N: usize>( &mut self, keys: [&Q; N], ) -> [Option<&mut V>; N]

Safety

impl<K, V, CM, H> MapIteration<K, V> for HashMap<K, V, CM, H>

where CM: CollectionMagnitude,

type Iterator<'a> = Iter<'a, K, V> where K: 'a, V: 'a, CM: 'a, H: 'a

The type of the iterator returned by Self::iter.

type KeyIterator<'a> = Keys<'a, K, V> where K: 'a, V: 'a, CM: 'a, H: 'a

The type of the iterator returned by Self::keys.

type ValueIterator<'a> = Values<'a, K, V> where K: 'a, V: 'a, CM: 'a, H: 'a

The type of the iterator returned by Self::values.

type MutIterator<'a> = IterMut<'a, K, V> where K: 'a, V: 'a, CM: 'a, H: 'a

The type of the mutable iterator returned by Self::iter_mut.

type ValueMutIterator<'a> = ValuesMut<'a, K, V> where K: 'a, V: 'a, CM: 'a, H: 'a

The type of the mutable iterator returned by Self::values_mut.

type IntoKeyIterator = IntoKeys<K, V>

The type of the iterator returned by Self::into_keys.

type IntoValueIterator = IntoValues<K, V>

The type of the iterator returned by Self::into_values.

fn iter(&self) -> Self::Iterator<'_>

An iterator visiting all entries in arbitrary order.

fn iter_mut(&mut self) -> Self::MutIterator<'_>

An iterator producing mutable references to all entries in arbitrary order.

fn keys(&self) -> Self::KeyIterator<'_>

An iterator visiting all keys in arbitrary order.

fn into_keys(self) -> Self::IntoKeyIterator

A consuming iterator visiting all keys in arbitrary order.

fn values(&self) -> Self::ValueIterator<'_>

An iterator visiting all values in arbitrary order.

fn values_mut(&mut self) -> Self::ValueMutIterator<'_>

An iterator visiting all values mutably in arbitrary order.

fn into_values(self) -> Self::IntoValueIterator

A consuming iterator visiting all values in arbitrary order.

impl<K, V, Q, CM, H> MapQuery<Q, V> for HashMap<K, V, CM, H>

where CM: CollectionMagnitude, Q: ?Sized + Equivalent<K>, H: Hasher<Q>,

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

Returns a reference to the value corresponding to the key.

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

Returns a mutable reference to the value corresponding to the key.

fn contains_key(&self, key: &Q) -> bool

Returns true if the map contains a value for the specified key.

impl<K, V, MT, CM, H> PartialEq<MT> for HashMap<K, V, CM, H>

where K: PartialEq, V: PartialEq, MT: MapQuery<K, V>, CM: CollectionMagnitude, H: Hasher<K>,

fn eq(&self, other: &MT) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<K, V, CM, H> Serialize for HashMap<K, V, CM, H>

where K: Serialize, V: Serialize, CM: CollectionMagnitude,

Available on crate feature serde only.

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<K, V, CM, H> Eq for HashMap<K, V, CM, H>

where K: Eq, V: Eq, CM: CollectionMagnitude, H: Hasher<K>,

impl<K, V, Q, CM, H> Map<K, V, Q> for HashMap<K, V, CM, H>

where CM: CollectionMagnitude, Q: ?Sized + Equivalent<K>, H: Hasher<Q>,