Struct bimap::hash::BiHashMap

pub struct BiHashMap<L, R, LS = RandomState, RS = RandomState> { /* private fields */ }

A bimap backed by two HashMaps.

See the module-level documentation for more details and examples.

Implementations

impl<L, R> BiHashMap<L, R, RandomState, RandomState>

where L: Eq + Hash, R: Eq + Hash,

pub fn new() -> Self

Creates an empty BiHashMap.

Examples

use bimap::BiHashMap;

let bimap = BiHashMap::<char, i32>::new();

pub fn with_capacity(capacity: usize) -> Self

Creates a new empty BiHashMap with the given capacity.

Examples

use bimap::BiHashMap;

let bimap = BiHashMap::<char, i32>::with_capacity(10);
assert!(bimap.capacity() >= 10);

impl<L, R, LS, RS> BiHashMap<L, R, LS, RS>

where L: Eq + Hash, R: Eq + Hash,

pub fn len(&self) -> usize

Returns the number of left-right pairs in the bimap.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
bimap.insert('b', 2);
bimap.insert('c', 3);
assert_eq!(bimap.len(), 3);

pub fn is_empty(&self) -> bool

Returns true if the bimap contains no left-right pairs, and false otherwise.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
assert!(bimap.is_empty());
bimap.insert('a', 1);
assert!(!bimap.is_empty());
bimap.remove_by_right(&1);
assert!(bimap.is_empty());

pub fn capacity(&self) -> usize

Returns a lower bound on the number of left-right pairs the BiHashMap can store without reallocating memory.

Examples

use bimap::BiHashMap;

let bimap = BiHashMap::<char, i32>::with_capacity(10);
assert!(bimap.capacity() >= 10);

pub fn clear(&mut self)

Removes all left-right pairs from the bimap.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
bimap.insert('b', 2);
bimap.insert('c', 3);
bimap.clear();
assert!(bimap.len() == 0);

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

Creates an iterator over the left-right pairs in the bimap in arbitrary order.

The iterator element type is (&L, &R).

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
bimap.insert('b', 2);
bimap.insert('c', 3);

for (left, right) in bimap.iter() {
    println!("({}, {})", left, right);
}

pub fn left_values(&self) -> LeftValues<'_, L, R>

Creates an iterator over the left values in the bimap in arbitrary order.

The iterator element type is &L.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
bimap.insert('b', 2);
bimap.insert('c', 3);

for char_value in bimap.left_values() {
    println!("{}", char_value);
}

pub fn right_values(&self) -> RightValues<'_, L, R>

Creates an iterator over the right values in the bimap in arbitrary order.

The iterator element type is &R.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
bimap.insert('b', 2);
bimap.insert('c', 3);

for int_value in bimap.right_values() {
    println!("{}", int_value);
}

impl<L, R, LS, RS> BiHashMap<L, R, LS, RS>

where L: Eq + Hash, R: Eq + Hash, LS: BuildHasher, RS: BuildHasher,

pub fn with_hashers(hash_builder_left: LS, hash_builder_right: RS) -> Self

Creates a new empty BiHashMap using hash_builder_left to hash left values and hash_builder_right to hash right values.

Examples

use std::collections::hash_map::RandomState;
use bimap::BiHashMap;

let s_left = RandomState::new();
let s_right = RandomState::new();
let mut bimap = BiHashMap::<char, i32>::with_hashers(s_left, s_right);
bimap.insert('a', 42);

pub fn with_capacity_and_hashers( capacity: usize, hash_builder_left: LS, hash_builder_right: RS ) -> Self

Creates a new empty BiHashMap with the given capacity, using hash_builder_left to hash left values and hash_builder_right to hash right values.

Examples

use std::collections::hash_map::RandomState;
use bimap::BiHashMap;

let s_left = RandomState::new();
let s_right = RandomState::new();
let bimap = BiHashMap::<char, i32>::with_capacity_and_hashers(10, s_left, s_right);
assert!(bimap.capacity() >= 10);

pub fn reserve(&mut self, additional: usize)

Reserves capacity for at least additional more elements to be inserted in the BiHashMap. The collection may reserve more space to avoid frequent reallocations.

Panics

Panics if the new allocation size overflows usize.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::<char, i32>::new();
bimap.reserve(10);
assert!(bimap.capacity() >= 10);

pub fn shrink_to_fit(&mut self)

Shrinks the capacity of the bimap as much as possible. It will drop down as much as possible while maintaining the internal rules and possibly leaving some space in accordance with the resize policy.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::<char, i32>::with_capacity(100);
bimap.insert('a', 1);
bimap.insert('b', 2);
assert!(bimap.capacity() >= 100);
bimap.shrink_to_fit();
assert!(bimap.capacity() >= 2);

pub fn shrink_to(&mut self, min_capacity: usize)

Shrinks the capacity of the bimap with a lower limit. It will drop down no lower than the supplied limit while maintaining the internal rules and possibly leaving some space in accordance with the resize policy.

If the current capacity is less than the lower limit, this is a no-op.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::<char, i32>::with_capacity(100);
bimap.insert('a', 1);
bimap.insert('b', 2);
assert!(bimap.capacity() >= 100);
bimap.shrink_to(10);
assert!(bimap.capacity() >= 10);
bimap.shrink_to(0);
assert!(bimap.capacity() >= 2);

pub fn get_by_left<Q>(&self, left: &Q) -> Option<&R>

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

Returns a reference to the right value corresponding to the given left value.

The input may be any borrowed form of the bimap’s left type, but Eq and Hash on the borrowed form must match those for the left type.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
assert_eq!(bimap.get_by_left(&'a'), Some(&1));
assert_eq!(bimap.get_by_left(&'z'), None);

pub fn get_by_right<Q>(&self, right: &Q) -> Option<&L>

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

Returns a reference to the left value corresponding to the given right value.

The input may be any borrowed form of the bimap’s right type, but Eq and Hash on the borrowed form must match those for the right type.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
assert_eq!(bimap.get_by_right(&1), Some(&'a'));
assert_eq!(bimap.get_by_right(&2), None);

pub fn contains_left<Q>(&self, left: &Q) -> bool

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

Returns true if the bimap contains the given left value and false otherwise.

The input may be any borrowed form of the bimap’s left type, but Eq and Hash on the borrowed form must match those for the left type.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
assert!(bimap.contains_left(&'a'));
assert!(!bimap.contains_left(&'b'));

pub fn contains_right<Q>(&self, right: &Q) -> bool

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

Returns true if the map contains the given right value and false otherwise.

The input may be any borrowed form of the bimap’s right type, but Eq and Hash on the borrowed form must match those for the right type.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
assert!(bimap.contains_right(&1));
assert!(!bimap.contains_right(&2));

pub fn remove_by_left<Q>(&mut self, left: &Q) -> Option<(L, R)>

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

Removes the left-right pair corresponding to the given left value.

Returns the previous left-right pair if the map contained the left value and None otherwise.

The input may be any borrowed form of the bimap’s left type, but Eq and Hash on the borrowed form must match those for the left type.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
bimap.insert('b', 2);
bimap.insert('c', 3);

assert_eq!(bimap.remove_by_left(&'b'), Some(('b', 2)));
assert_eq!(bimap.remove_by_left(&'b'), None);

pub fn remove_by_right<Q>(&mut self, right: &Q) -> Option<(L, R)>

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

Removes the left-right pair corresponding to the given right value.

Returns the previous left-right pair if the map contained the right value and None otherwise.

The input may be any borrowed form of the bimap’s right type, but Eq and Hash on the borrowed form must match those for the right type.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
bimap.insert('b', 2);
bimap.insert('c', 3);

assert_eq!(bimap.remove_by_right(&2), Some(('b', 2)));
assert_eq!(bimap.remove_by_right(&2), None);

pub fn insert(&mut self, left: L, right: R) -> Overwritten<L, R>

Inserts the given left-right pair into the bimap.

Returns an enum Overwritten representing any left-right pairs that were overwritten by the call to insert. The example below details all possible enum variants that can be returned.

Warnings

Somewhat paradoxically, calling insert() can actually reduce the size of the bimap! This is because of the invariant that each left value maps to exactly one right value and vice versa.

Examples

use bimap::{BiHashMap, Overwritten};

let mut bimap = BiHashMap::new();
assert_eq!(bimap.len(), 0); // {}

// no values are overwritten.
assert_eq!(bimap.insert('a', 1), Overwritten::Neither);
assert_eq!(bimap.len(), 1); // {'a' <> 1}

// no values are overwritten.
assert_eq!(bimap.insert('b', 2), Overwritten::Neither);
assert_eq!(bimap.len(), 2); // {'a' <> 1, 'b' <> 2}

// ('a', 1) already exists, so inserting ('a', 4) overwrites 'a', the left value.
// the previous left-right pair ('a', 1) is returned.
assert_eq!(bimap.insert('a', 4), Overwritten::Left('a', 1));
assert_eq!(bimap.len(), 2); // {'a' <> 4, 'b' <> 2}

// ('b', 2) already exists, so inserting ('c', 2) overwrites 2, the right value.
// the previous left-right pair ('b', 2) is returned.
assert_eq!(bimap.insert('c', 2), Overwritten::Right('b', 2));
assert_eq!(bimap.len(), 2); // {'a' <> 1, 'c' <> 2}

// both ('a', 4) and ('c', 2) already exist, so inserting ('a', 2) overwrites both.
// ('a', 4) has the overwritten left value ('a'), so it's the first tuple returned.
// ('c', 2) has the overwritten right value (2), so it's the second tuple returned.
assert_eq!(bimap.insert('a', 2), Overwritten::Both(('a', 4), ('c', 2)));
assert_eq!(bimap.len(), 1); // {'a' <> 2} // bimap is smaller than before!

// ('a', 2) already exists, so inserting ('a', 2) overwrites the pair.
// the previous left-right pair ('a', 2) is returned.
assert_eq!(bimap.insert('a', 2), Overwritten::Pair('a', 2));
assert_eq!(bimap.len(), 1); // {'a' <> 2}

pub fn insert_no_overwrite(&mut self, left: L, right: R) -> Result<(), (L, R)>

Inserts the given left-right pair into the bimap without overwriting any existing values.

Returns Ok(()) if the pair was successfully inserted into the bimap. If either value exists in the map, Err((left, right) is returned with the attempted left-right pair and the map is unchanged.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
assert_eq!(bimap.insert_no_overwrite('a', 1), Ok(()));
assert_eq!(bimap.insert_no_overwrite('b', 2), Ok(()));
assert_eq!(bimap.insert_no_overwrite('a', 3), Err(('a', 3)));
assert_eq!(bimap.insert_no_overwrite('c', 2), Err(('c', 2)));

pub fn retain<F>(&mut self, f: F)

where F: FnMut(&L, &R) -> bool,

Retains only the elements specified by the predicate.

In other words, remove all left-right pairs (l, r) such that f(&l, &r) returns false.

Examples

use bimap::BiHashMap;

let mut bimap = BiHashMap::new();
bimap.insert('a', 1);
bimap.insert('b', 2);
bimap.insert('c', 3);
bimap.retain(|&l, &r| r >= 2);
assert_eq!(bimap.len(), 2);
assert_eq!(bimap.get_by_left(&'b'), Some(&2));
assert_eq!(bimap.get_by_left(&'c'), Some(&3));
assert_eq!(bimap.get_by_left(&'a'), None);

Trait Implementations

impl<L, R, LS, RS> Clone for BiHashMap<L, R, LS, RS>

where L: Clone + Eq + Hash, R: Clone + Eq + Hash, LS: BuildHasher + Clone, RS: BuildHasher + Clone,

fn clone(&self) -> BiHashMap<L, R, LS, RS>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<L, R, LS, RS> Debug for BiHashMap<L, R, LS, RS>

where L: Debug, R: Debug,

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

Formats the value using the given formatter.

impl<L, R, LS, RS> Default for BiHashMap<L, R, LS, RS>

where L: Eq + Hash, R: Eq + Hash, LS: BuildHasher + Default, RS: BuildHasher + Default,

fn default() -> BiHashMap<L, R, LS, RS>

Returns the “default value” for a type.

impl<L, R, LS, RS> Extend<(L, R)> for BiHashMap<L, R, LS, RS>

where L: Eq + Hash, R: Eq + Hash, LS: BuildHasher, RS: BuildHasher,

fn extend<T: IntoIterator<Item = (L, R)>>(&mut self, iter: T)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl<L, R, LS, RS> FromIterator<(L, R)> for BiHashMap<L, R, LS, RS>

where L: Eq + Hash, R: Eq + Hash, LS: BuildHasher + Default, RS: BuildHasher + Default,

fn from_iter<I>(iter: I) -> BiHashMap<L, R, LS, RS>

where I: IntoIterator<Item = (L, R)>,

Creates a value from an iterator.

impl<'a, L, R, LS, RS> IntoIterator for &'a BiHashMap<L, R, LS, RS>

where L: Eq + Hash, R: Eq + Hash,

type Item = (&'a L, &'a R)

The type of the elements being iterated over.

type IntoIter = Iter<'a, L, R>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Iter<'a, L, R>

Creates an iterator from a value.

impl<L, R, LS, RS> IntoIterator for BiHashMap<L, R, LS, RS>

where L: Eq + Hash, R: Eq + Hash,

type Item = (L, R)

The type of the elements being iterated over.

type IntoIter = IntoIter<L, R>

Which kind of iterator are we turning this into?

fn into_iter(self) -> IntoIter<L, R>

Creates an iterator from a value.

impl<L, R, LS, RS> PartialEq for BiHashMap<L, R, LS, RS>

where L: Eq + Hash, R: Eq + Hash, LS: BuildHasher, RS: BuildHasher,

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

This method tests for self and other values to be equal, and is used by ==.

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

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

impl<L, R, LS, RS> Eq for BiHashMap<L, R, LS, RS>

where L: Eq + Hash, R: Eq + Hash, LS: BuildHasher, RS: BuildHasher,

impl<L, R, LS, RS> Send for BiHashMap<L, R, LS, RS>

where L: Send, R: Send, LS: Send, RS: Send,

impl<L, R, LS, RS> Sync for BiHashMap<L, R, LS, RS>

where L: Sync, R: Sync, LS: Sync, RS: Sync,