|
|
|
|
Quelle map.rs
Sprache: unbekannt
|
|
use crate::raw::{
Allocator, Bucket, Global, RawDrain, RawExtractIf, RawIntoIter, RawIter, RawTable,
};
use crate::{Equivalent, TryReserveError};
use core::borrow::Borrow;
use core::fmt::{self, Debug};
use core::hash::{BuildHasher, Hash};
use core::iter::FusedIterator;
use core::marker::PhantomData;
use core::mem;
use core::ops::Index;
/// Default hasher for `HashMap`.
#[cfg(feature = "ahash")]
pub type DefaultHashBuilder = core::hash::BuildHasherDefault<ahash::AHasher>;
/// Dummy default hasher for `HashMap`.
#[cfg(not(feature = "ahash"))]
pub enum DefaultHashBuilder {}
/// A hash map implemented with quadratic probing and SIMD lookup.
///
/// The default hashing algorithm is currently [`AHash`], though this is
/// subject to change at any point in the future. This hash function is very
/// fast for all types of keys, but this algorithm will typically *not* protect
/// against attacks such as HashDoS.
///
/// The hashing algorithm can be replaced on a per-`HashMap` basis using the
/// [`default`], [`with_hasher`], and [`with_capacity_and_hasher`] methods. Many
/// alternative algorithms are available on crates.io, such as the [`fnv`] crate.
///
/// It is required that the keys implement the [`Eq`] and [`Hash`] traits, although
/// this can frequently be achieved by using `#[derive(PartialEq, Eq, Hash)]`.
/// If you implement these yourself, it is important that the following
/// property holds:
///
/// ```text
/// k1 == k2 -> hash(k1) == hash(k2)
/// ```
///
/// In other words, if two keys are equal, their hashes must be equal.
///
/// It is 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 map. This is normally only
/// possible through [`Cell`], [`RefCell`], global state, I/O, or unsafe code.
///
/// It is also a logic error for the [`Hash`] implementation of a key to panic.
/// This is generally only possible if the trait is implemented manually. If a
/// panic does occur then the contents of the `HashMap` may become corrupted and
/// some items may be dropped from the table.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// // Type inference lets us omit an explicit type signature (which
/// // would be `HashMap<String, String>` in this example).
/// let mut book_reviews = HashMap::new();
///
/// // Review some books.
/// book_reviews.insert(
/// "Adventures of Huckleberry Finn".to_string(),
/// "My favorite book.".to_string(),
/// );
/// book_reviews.insert(
/// "Grimms' Fairy Tales".to_string(),
/// "Masterpiece.".to_string(),
/// );
/// book_reviews.insert(
/// "Pride and Prejudice".to_string(),
/// "Very enjoyable.".to_string(),
/// );
/// book_reviews.insert(
/// "The Adventures of Sherlock Holmes".to_string(),
/// "Eye lyked it alot.".to_string(),
/// );
///
/// // Check for a specific one.
/// // When collections store owned values (String), they can still be
/// // queried using references (&str).
/// if !book_reviews.contains_key("Les Misérables") {
/// println!("We've got {} reviews, but Les Misérables ain't one.",
/// book_reviews.len());
/// }
///
/// // oops, this review has a lot of spelling mistakes, let's delete it.
/// book_reviews.remove("The Adventures of Sherlock Holmes");
///
/// // Look up the values associated with some keys.
/// let to_find = ["Pride and Prejudice", "Alice's Adventure in Wonderland"];
/// for &book in &to_find {
/// match book_reviews.get(book) {
/// Some(review) => println!("{}: {}", book, review),
/// None => println!("{} is unreviewed.", book)
/// }
/// }
///
/// // Look up the value for a key (will panic if the key is not found).
/// println!("Review for Jane: {}", book_reviews["Pride and Prejudice"]);
///
/// // Iterate over everything.
/// for (book, review) in &book_reviews {
/// println!("{}: \"{}\"", book, review);
/// }
/// ```
///
/// `HashMap` also implements an [`Entry API`](#method.entry), which allows
/// for more complex methods of getting, setting, updating and removing keys and
/// their values:
///
/// ```
/// use hashbrown::HashMap;
///
/// // type inference lets us omit an explicit type signature (which
/// // would be `HashMap<&str, u8>` in this example).
/// let mut player_stats = HashMap::new();
///
/// fn random_stat_buff() -> u8 {
/// // could actually return some random value here - let's just return
/// // some fixed value for now
/// 42
/// }
///
/// // insert a key only if it doesn't already exist
/// player_stats.entry("health").or_insert(100);
///
/// // insert a key using a function that provides a new value only if it
/// // doesn't already exist
/// player_stats.entry("defence").or_insert_with(random_stat_buff);
///
/// // update a key, guarding against the key possibly not being set
/// let stat = player_stats.entry("attack").or_insert(100);
/// *stat += random_stat_buff();
/// ```
///
/// The easiest way to use `HashMap` with a custom key type is to derive [`Eq`] and [`Hash`].
/// We must also derive [`PartialEq`].
///
/// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
/// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
/// [`PartialEq`]: https://doc.rust-lang.org/std/cmp/trait.PartialEq.html
/// [`RefCell`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html
/// [`Cell`]: https://doc.rust-lang.org/std/cell/struct.Cell.html
/// [`default`]: #method.default
/// [`with_hasher`]: #method.with_hasher
/// [`with_capacity_and_hasher`]: #method.with_capacity_and_hasher
/// [`fnv`]: https://crates.io/crates/fnv
/// [`AHash`]: https://crates.io/crates/ahash
///
/// ```
/// use hashbrown::HashMap;
///
/// #[derive(Hash, Eq, PartialEq, Debug)]
/// struct Viking {
/// name: String,
/// country: String,
/// }
///
/// impl Viking {
/// /// Creates a new Viking.
/// fn new(name: &str, country: &str) -> Viking {
/// Viking { name: name.to_string(), country: country.to_string() }
/// }
/// }
///
/// // Use a HashMap to store the vikings' health points.
/// let mut vikings = HashMap::new();
///
/// vikings.insert(Viking::new("Einar", "Norway"), 25);
/// vikings.insert(Viking::new("Olaf", "Denmark"), 24);
/// vikings.insert(Viking::new("Harald", "Iceland"), 12);
///
/// // Use derived implementation to print the status of the vikings.
/// for (viking, health) in &vikings {
/// println!("{:?} has {} hp", viking, health);
/// }
/// ```
///
/// A `HashMap` with fixed list of elements can be initialized from an array:
///
/// ```
/// use hashbrown::HashMap;
///
/// let timber_resources: HashMap<&str, i32> = [("Norway", 100), ("Denmark", 50), ("Iceland" , 10)]
/// .into_iter().collect();
/// // use the values stored in map
/// ```
pub struct HashMap<K, V, S = DefaultHashBuilder, A: Allocator = Global> {
pub(crate) hash_builder: S,
pub(crate) table: RawTable<(K, V), A>,
}
impl<K: Clone, V: Clone, S: Clone, A: Allocator + Clone> Clone for HashMap<K, V, S, A> {
fn clone(&self) -> Self {
HashMap {
hash_builder: self.hash_builder.clone(),
table: self.table.clone(),
}
}
fn clone_from(&mut self, source: &Self) {
self.table.clone_from(&source.table);
// Update hash_builder only if we successfully cloned all elements.
self.hash_builder.clone_from(&source.hash_builder);
}
}
/// Ensures that a single closure type across uses of this which, in turn prevents multiple
/// instances of any functions like RawTable::reserve from being generated
#[cfg_attr(feature = "inline-more", inline)]
pub(crate) fn make_hasher<Q, V, S>(hash_builder: &S) -> impl Fn(&(Q, V)) -> u64 + '_
where
Q: Hash,
S: BuildHasher,
{
move |val| make_hash::<Q, S>(hash_builder, &val.0)
}
/// Ensures that a single closure type across uses of this which, in turn prevents multiple
/// instances of any functions like RawTable::reserve from being generated
#[cfg_attr(feature = "inline-more", inline)]
fn equivalent_key<Q, K, V>(k: &Q) -> impl Fn(&(K, V)) -> bool + '_
where
Q: ?Sized + Equivalent<K>,
{
move |x| k.equivalent(&x.0)
}
/// Ensures that a single closure type across uses of this which, in turn prevents multiple
/// instances of any functions like RawTable::reserve from being generated
#[cfg_attr(feature = "inline-more", inline)]
fn equivalent<Q, K>(k: &Q) -> impl Fn(&K) -> bool + '_
where
Q: ?Sized + Equivalent<K>,
{
move |x| k.equivalent(x)
}
#[cfg(not(feature = "nightly"))]
#[cfg_attr(feature = "inline-more", inline)]
pub(crate) fn make_hash<Q, S>(hash_builder: &S, val: &Q) -> u64
where
Q: Hash + ?Sized,
S: BuildHasher,
{
use core::hash::Hasher;
let mut state = hash_builder.build_hasher();
val.hash(&mut state);
state.finish()
}
#[cfg(feature = "nightly")]
#[cfg_attr(feature = "inline-more", inline)]
pub(crate) fn make_hash<Q, S>(hash_builder: &S, val: &Q) -> u64
where
Q: Hash + ?Sized,
S: BuildHasher,
{
hash_builder.hash_one(val)
}
#[cfg(feature = "ahash")]
impl<K, V> HashMap<K, V, DefaultHashBuilder> {
/// Creates an empty `HashMap`.
///
/// The hash map is initially created with a capacity of 0, so it will not allocate until it
/// is first inserted into.
///
/// # HashDoS resistance
///
/// The `hash_builder` normally use a fixed key by default and that does
/// not allow the `HashMap` to be protected against attacks such as [`HashDoS`].
/// Users who require HashDoS resistance should explicitly use
/// [`ahash::RandomState`] or [`std::collections::hash_map::RandomState`]
/// as the hasher when creating a [`HashMap`], for example with
/// [`with_hasher`](HashMap::with_hasher) method.
///
/// [`HashDoS`]: https://en.wikipedia.org/wiki/Collision_attack
/// [`std::collections::hash_map::RandomState`]: https://doc.rust-lang.org/std/collections/hash_map/struct.RandomState.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
/// let mut map: HashMap<&str, i32> = HashMap::new();
/// assert_eq!(map.len(), 0);
/// assert_eq!(map.capacity(), 0);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn new() -> Self {
Self::default()
}
/// Creates an empty `HashMap` with the specified capacity.
///
/// The hash map will be able to hold at least `capacity` elements without
/// reallocating. If `capacity` is 0, the hash map will not allocate.
///
/// # HashDoS resistance
///
/// The `hash_builder` normally use a fixed key by default and that does
/// not allow the `HashMap` to be protected against attacks such as [`HashDoS`].
/// Users who require HashDoS resistance should explicitly use
/// [`ahash::RandomState`] or [`std::collections::hash_map::RandomState`]
/// as the hasher when creating a [`HashMap`], for example with
/// [`with_capacity_and_hasher`](HashMap::with_capacity_and_hasher) method.
///
/// [`HashDoS`]: https://en.wikipedia.org/wiki/Collision_attack
/// [`std::collections::hash_map::RandomState`]: https://doc.rust-lang.org/std/collections/hash_map/struct.RandomState.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
/// let mut map: HashMap<&str, i32> = HashMap::with_capacity(10);
/// assert_eq!(map.len(), 0);
/// assert!(map.capacity() >= 10);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn with_capacity(capacity: usize) -> Self {
Self::with_capacity_and_hasher(capacity, DefaultHashBuilder::default())
}
}
#[cfg(feature = "ahash")]
impl<K, V, A: Allocator> HashMap<K, V, DefaultHashBuilder, A> {
/// Creates an empty `HashMap` using the given allocator.
///
/// The hash map is initially created with a capacity of 0, so it will not allocate until it
/// is first inserted into.
///
/// # HashDoS resistance
///
/// The `hash_builder` normally use a fixed key by default and that does
/// not allow the `HashMap` to be protected against attacks such as [`HashDoS`].
/// Users who require HashDoS resistance should explicitly use
/// [`ahash::RandomState`] or [`std::collections::hash_map::RandomState`]
/// as the hasher when creating a [`HashMap`], for example with
/// [`with_hasher_in`](HashMap::with_hasher_in) method.
///
/// [`HashDoS`]: https://en.wikipedia.org/wiki/Collision_attack
/// [`std::collections::hash_map::RandomState`]: https://doc.rust-lang.org/std/collections/hash_map/struct.RandomState.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
/// use bumpalo::Bump;
///
/// let bump = Bump::new();
/// let mut map = HashMap::new_in(&bump);
///
/// // The created HashMap holds none elements
/// assert_eq!(map.len(), 0);
///
/// // The created HashMap also doesn't allocate memory
/// assert_eq!(map.capacity(), 0);
///
/// // Now we insert element inside created HashMap
/// map.insert("One", 1);
/// // We can see that the HashMap holds 1 element
/// assert_eq!(map.len(), 1);
/// // And it also allocates some capacity
/// assert!(map.capacity() > 1);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn new_in(alloc: A) -> Self {
Self::with_hasher_in(DefaultHashBuilder::default(), alloc)
}
/// Creates an empty `HashMap` with the specified capacity using the given allocator.
///
/// The hash map will be able to hold at least `capacity` elements without
/// reallocating. If `capacity` is 0, the hash map will not allocate.
///
/// # HashDoS resistance
///
/// The `hash_builder` normally use a fixed key by default and that does
/// not allow the `HashMap` to be protected against attacks such as [`HashDoS`].
/// Users who require HashDoS resistance should explicitly use
/// [`ahash::RandomState`] or [`std::collections::hash_map::RandomState`]
/// as the hasher when creating a [`HashMap`], for example with
/// [`with_capacity_and_hasher_in`](HashMap::with_capacity_and_hasher_in) method.
///
/// [`HashDoS`]: https://en.wikipedia.org/wiki/Collision_attack
/// [`std::collections::hash_map::RandomState`]: https://doc.rust-lang.org/std/collections/hash_map/struct.RandomState.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
/// use bumpalo::Bump;
///
/// let bump = Bump::new();
/// let mut map = HashMap::with_capacity_in(5, &bump);
///
/// // The created HashMap holds none elements
/// assert_eq!(map.len(), 0);
/// // But it can hold at least 5 elements without reallocating
/// let empty_map_capacity = map.capacity();
/// assert!(empty_map_capacity >= 5);
///
/// // Now we insert some 5 elements inside created HashMap
/// map.insert("One", 1);
/// map.insert("Two", 2);
/// map.insert("Three", 3);
/// map.insert("Four", 4);
/// map.insert("Five", 5);
///
/// // We can see that the HashMap holds 5 elements
/// assert_eq!(map.len(), 5);
/// // But its capacity isn't changed
/// assert_eq!(map.capacity(), empty_map_capacity)
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn with_capacity_in(capacity: usize, alloc: A) -> Self {
Self::with_capacity_and_hasher_in(capacity, DefaultHashBuilder::default(), alloc)
}
}
impl<K, V, S> HashMap<K, V, S> {
/// Creates an empty `HashMap` which will use the given hash builder to hash
/// keys.
///
/// The hash map is initially created with a capacity of 0, so it will not
/// allocate until it is first inserted into.
///
/// # HashDoS resistance
///
/// The `hash_builder` normally use a fixed key by default and that does
/// not allow the `HashMap` to be protected against attacks such as [`HashDoS`].
/// Users who require HashDoS resistance should explicitly use
/// [`ahash::RandomState`] or [`std::collections::hash_map::RandomState`]
/// as the hasher when creating a [`HashMap`].
///
/// The `hash_builder` passed should implement the [`BuildHasher`] trait for
/// the HashMap to be useful, see its documentation for details.
///
/// [`HashDoS`]: https://en.wikipedia.org/wiki/Collision_attack
/// [`std::collections::hash_map::RandomState`]: https://doc.rust-lang.org/std/collections/hash_map/struct.RandomState.html
/// [`BuildHasher`]: https://doc.rust-lang.org/std/hash/trait.BuildHasher.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
/// use hashbrown::hash_map::DefaultHashBuilder;
///
/// let s = DefaultHashBuilder::default();
/// let mut map = HashMap::with_hasher(s);
/// assert_eq!(map.len(), 0);
/// assert_eq!(map.capacity(), 0);
///
/// map.insert(1, 2);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub const fn with_hasher(hash_builder: S) -> Self {
Self {
hash_builder,
table: RawTable::new(),
}
}
/// Creates an empty `HashMap` with the specified capacity, using `hash_builder`
/// to hash the keys.
///
/// The hash map will be able to hold at least `capacity` elements without
/// reallocating. If `capacity` is 0, the hash map will not allocate.
///
/// # HashDoS resistance
///
/// The `hash_builder` normally use a fixed key by default and that does
/// not allow the `HashMap` to be protected against attacks such as [`HashDoS`].
/// Users who require HashDoS resistance should explicitly use
/// [`ahash::RandomState`] or [`std::collections::hash_map::RandomState`]
/// as the hasher when creating a [`HashMap`].
///
/// The `hash_builder` passed should implement the [`BuildHasher`] trait for
/// the HashMap to be useful, see its documentation for details.
///
/// [`HashDoS`]: https://en.wikipedia.org/wiki/Collision_attack
/// [`std::collections::hash_map::RandomState`]: https://doc.rust-lang.org/std/collections/hash_map/struct.RandomState.html
/// [`BuildHasher`]: https://doc.rust-lang.org/std/hash/trait.BuildHasher.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
/// use hashbrown::hash_map::DefaultHashBuilder;
///
/// let s = DefaultHashBuilder::default();
/// let mut map = HashMap::with_capacity_and_hasher(10, s);
/// assert_eq!(map.len(), 0);
/// assert!(map.capacity() >= 10);
///
/// map.insert(1, 2);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn with_capacity_and_hasher(capacity: usize, hash_builder: S) -> Self {
Self {
hash_builder,
table: RawTable::with_capacity(capacity),
}
}
}
impl<K, V, S, A: Allocator> HashMap<K, V, S, A> {
/// Returns a reference to the underlying allocator.
#[inline]
pub fn allocator(&self) -> &A {
self.table.allocator()
}
/// Creates an empty `HashMap` which will use the given hash builder to hash
/// keys. It will be allocated with the given allocator.
///
/// The hash map is initially created with a capacity of 0, so it will not allocate until it
/// is first inserted into.
///
/// # HashDoS resistance
///
/// The `hash_builder` normally use a fixed key by default and that does
/// not allow the `HashMap` to be protected against attacks such as [`HashDoS`].
/// Users who require HashDoS resistance should explicitly use
/// [`ahash::RandomState`] or [`std::collections::hash_map::RandomState`]
/// as the hasher when creating a [`HashMap`].
///
/// [`HashDoS`]: https://en.wikipedia.org/wiki/Collision_attack
/// [`std::collections::hash_map::RandomState`]: https://doc.rust-lang.org/std/collections/hash_map/struct.RandomState.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
/// use hashbrown::hash_map::DefaultHashBuilder;
///
/// let s = DefaultHashBuilder::default();
/// let mut map = HashMap::with_hasher(s);
/// map.insert(1, 2);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub const fn with_hasher_in(hash_builder: S, alloc: A) -> Self {
Self {
hash_builder,
table: RawTable::new_in(alloc),
}
}
/// Creates an empty `HashMap` with the specified capacity, using `hash_builder`
/// to hash the keys. It will be allocated with the given allocator.
///
/// The hash map will be able to hold at least `capacity` elements without
/// reallocating. If `capacity` is 0, the hash map will not allocate.
///
/// # HashDoS resistance
///
/// The `hash_builder` normally use a fixed key by default and that does
/// not allow the `HashMap` to be protected against attacks such as [`HashDoS`].
/// Users who require HashDoS resistance should explicitly use
/// [`ahash::RandomState`] or [`std::collections::hash_map::RandomState`]
/// as the hasher when creating a [`HashMap`].
///
/// [`HashDoS`]: https://en.wikipedia.org/wiki/Collision_attack
/// [`std::collections::hash_map::RandomState`]: https://doc.rust-lang.org/std/collections/hash_map/struct.RandomState.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
/// use hashbrown::hash_map::DefaultHashBuilder;
///
/// let s = DefaultHashBuilder::default();
/// let mut map = HashMap::with_capacity_and_hasher(10, s);
/// map.insert(1, 2);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn with_capacity_and_hasher_in(capacity: usize, hash_builder: S, alloc: A) -> Self {
Self {
hash_builder,
table: RawTable::with_capacity_in(capacity, alloc),
}
}
/// Returns a reference to the map's [`BuildHasher`].
///
/// [`BuildHasher`]: https://doc.rust-lang.org/std/hash/trait.BuildHasher.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
/// use hashbrown::hash_map::DefaultHashBuilder;
///
/// let hasher = DefaultHashBuilder::default();
/// let map: HashMap<i32, i32> = HashMap::with_hasher(hasher);
/// let hasher: &DefaultHashBuilder = map.hasher();
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn hasher(&self) -> &S {
&self.hash_builder
}
/// Returns the number of elements the map can hold without reallocating.
///
/// This number is a lower bound; the `HashMap<K, V>` might be able to hold
/// more, but is guaranteed to be able to hold at least this many.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
/// let map: HashMap<i32, i32> = HashMap::with_capacity(100);
/// assert_eq!(map.len(), 0);
/// assert!(map.capacity() >= 100);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn capacity(&self) -> usize {
self.table.capacity()
}
/// An iterator visiting all keys in arbitrary order.
/// The iterator element type is `&'a K`.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// map.insert("a", 1);
/// map.insert("b", 2);
/// map.insert("c", 3);
/// assert_eq!(map.len(), 3);
/// let mut vec: Vec<&str> = Vec::new();
///
/// for key in map.keys() {
/// println!("{}", key);
/// vec.push(*key);
/// }
///
/// // The `Keys` iterator produces keys in arbitrary order, so the
/// // keys must be sorted to test them against a sorted array.
/// vec.sort_unstable();
/// assert_eq!(vec, ["a", "b", "c"]);
///
/// assert_eq!(map.len(), 3);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn keys(&self) -> Keys<'_, K, V> {
Keys { inner: self.iter() }
}
/// An iterator visiting all values in arbitrary order.
/// The iterator element type is `&'a V`.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// map.insert("a", 1);
/// map.insert("b", 2);
/// map.insert("c", 3);
/// assert_eq!(map.len(), 3);
/// let mut vec: Vec<i32> = Vec::new();
///
/// for val in map.values() {
/// println!("{}", val);
/// vec.push(*val);
/// }
///
/// // The `Values` iterator produces values in arbitrary order, so the
/// // values must be sorted to test them against a sorted array.
/// vec.sort_unstable();
/// assert_eq!(vec, [1, 2, 3]);
///
/// assert_eq!(map.len(), 3);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn values(&self) -> Values<'_, K, V> {
Values { inner: self.iter() }
}
/// An iterator visiting all values mutably in arbitrary order.
/// The iterator element type is `&'a mut V`.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
///
/// map.insert("a", 1);
/// map.insert("b", 2);
/// map.insert("c", 3);
///
/// for val in map.values_mut() {
/// *val = *val + 10;
/// }
///
/// assert_eq!(map.len(), 3);
/// let mut vec: Vec<i32> = Vec::new();
///
/// for val in map.values() {
/// println!("{}", val);
/// vec.push(*val);
/// }
///
/// // The `Values` iterator produces values in arbitrary order, so the
/// // values must be sorted to test them against a sorted array.
/// vec.sort_unstable();
/// assert_eq!(vec, [11, 12, 13]);
///
/// assert_eq!(map.len(), 3);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn values_mut(&mut self) -> ValuesMut<'_, K, V> {
ValuesMut {
inner: self.iter_mut(),
}
}
/// An iterator visiting all key-value pairs in arbitrary order.
/// The iterator element type is `(&'a K, &'a V)`.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// map.insert("a", 1);
/// map.insert("b", 2);
/// map.insert("c", 3);
/// assert_eq!(map.len(), 3);
/// let mut vec: Vec<(&str, i32)> = Vec::new();
///
/// for (key, val) in map.iter() {
/// println!("key: {} val: {}", key, val);
/// vec.push((*key, *val));
/// }
///
/// // The `Iter` iterator produces items in arbitrary order, so the
/// // items must be sorted to test them against a sorted array.
/// vec.sort_unstable();
/// assert_eq!(vec, [("a", 1), ("b", 2), ("c", 3)]);
///
/// assert_eq!(map.len(), 3);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn iter(&self) -> Iter<'_, K, V> {
// Here we tie the lifetime of self to the iter.
unsafe {
Iter {
inner: self.table.iter(),
marker: PhantomData,
}
}
}
/// An iterator visiting all key-value pairs in arbitrary order,
/// with mutable references to the values.
/// The iterator element type is `(&'a K, &'a mut V)`.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// map.insert("a", 1);
/// map.insert("b", 2);
/// map.insert("c", 3);
///
/// // Update all values
/// for (_, val) in map.iter_mut() {
/// *val *= 2;
/// }
///
/// assert_eq!(map.len(), 3);
/// let mut vec: Vec<(&str, i32)> = Vec::new();
///
/// for (key, val) in &map {
/// println!("key: {} val: {}", key, val);
/// vec.push((*key, *val));
/// }
///
/// // The `Iter` iterator produces items in arbitrary order, so the
/// // items must be sorted to test them against a sorted array.
/// vec.sort_unstable();
/// assert_eq!(vec, [("a", 2), ("b", 4), ("c", 6)]);
///
/// assert_eq!(map.len(), 3);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn iter_mut(&mut self) -> IterMut<'_, K, V> {
// Here we tie the lifetime of self to the iter.
unsafe {
IterMut {
inner: self.table.iter(),
marker: PhantomData,
}
}
}
#[cfg(test)]
#[cfg_attr(feature = "inline-more", inline)]
fn raw_capacity(&self) -> usize {
self.table.buckets()
}
/// Returns the number of elements in the map.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut a = HashMap::new();
/// assert_eq!(a.len(), 0);
/// a.insert(1, "a");
/// assert_eq!(a.len(), 1);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn len(&self) -> usize {
self.table.len()
}
/// Returns `true` if the map contains no elements.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut a = HashMap::new();
/// assert!(a.is_empty());
/// a.insert(1, "a");
/// assert!(!a.is_empty());
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn is_empty(&self) -> bool {
self.len() == 0
}
/// Clears the map, returning all key-value pairs as an iterator. Keeps the
/// allocated memory for reuse.
///
/// If the returned iterator is dropped before being fully consumed, it
/// drops the remaining key-value pairs. The returned iterator keeps a
/// mutable borrow on the vector to optimize its implementation.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut a = HashMap::new();
/// a.insert(1, "a");
/// a.insert(2, "b");
/// let capacity_before_drain = a.capacity();
///
/// for (k, v) in a.drain().take(1) {
/// assert!(k == 1 || k == 2);
/// assert!(v == "a" || v == "b");
/// }
///
/// // As we can see, the map is empty and contains no element.
/// assert!(a.is_empty() && a.len() == 0);
/// // But map capacity is equal to old one.
/// assert_eq!(a.capacity(), capacity_before_drain);
///
/// let mut a = HashMap::new();
/// a.insert(1, "a");
/// a.insert(2, "b");
///
/// { // Iterator is dropped without being consumed.
/// let d = a.drain();
/// }
///
/// // But the map is empty even if we do not use Drain iterator.
/// assert!(a.is_empty());
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn drain(&mut self) -> Drain<'_, K, V, A> {
Drain {
inner: self.table.drain(),
}
}
/// Retains only the elements specified by the predicate. Keeps the
/// allocated memory for reuse.
///
/// In other words, remove all pairs `(k, v)` such that `f(&k, &mut v)` returns `false`.
/// The elements are visited in unsorted (and unspecified) order.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map: HashMap<i32, i32> = (0..8).map(|x|(x, x*10)).collect();
/// assert_eq!(map.len(), 8);
///
/// map.retain(|&k, _| k % 2 == 0);
///
/// // We can see, that the number of elements inside map is changed.
/// assert_eq!(map.len(), 4);
///
/// let mut vec: Vec<(i32, i32)> = map.iter().map(|(&k, &v)| (k, v)).collect();
/// vec.sort_unstable();
/// assert_eq!(vec, [(0, 0), (2, 20), (4, 40), (6, 60)]);
/// ```
pub fn retain<F>(&mut self, mut f: F)
where
F: FnMut(&K, &mut V) -> bool,
{
// Here we only use `iter` as a temporary, preventing use-after-free
unsafe {
for item in self.table.iter() {
let &mut (ref key, ref mut value) = item.as_mut();
if !f(key, value) {
self.table.erase(item);
}
}
}
}
/// Drains elements which are true under the given predicate,
/// and returns an iterator over the removed items.
///
/// In other words, move all pairs `(k, v)` such that `f(&k, &mut v)` returns `true` out
/// into another iterator.
///
/// Note that `extract_if` lets you mutate every value in the filter closure, regardless of
/// whether you choose to keep or remove it.
///
/// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating
/// or the iteration short-circuits, then the remaining elements will be retained.
/// Use [`retain()`] with a negated predicate if you do not need the returned iterator.
///
/// Keeps the allocated memory for reuse.
///
/// [`retain()`]: HashMap::retain
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map: HashMap<i32, i32> = (0..8).map(|x| (x, x)).collect();
///
/// let drained: HashMap<i32, i32> = map.extract_if(|k, _v| k % 2 == 0).collect();
///
/// let mut evens = drained.keys().cloned().collect::<Vec<_>>();
/// let mut odds = map.keys().cloned().collect::<Vec<_>>();
/// evens.sort();
/// odds.sort();
///
/// assert_eq!(evens, vec![0, 2, 4, 6]);
/// assert_eq!(odds, vec![1, 3, 5, 7]);
///
/// let mut map: HashMap<i32, i32> = (0..8).map(|x| (x, x)).collect();
///
/// { // Iterator is dropped without being consumed.
/// let d = map.extract_if(|k, _v| k % 2 != 0);
/// }
///
/// // ExtractIf was not exhausted, therefore no elements were drained.
/// assert_eq!(map.len(), 8);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn extract_if<F>(&mut self, f: F) -> ExtractIf<'_, K, V, F, A>
where
F: FnMut(&K, &mut V) -> bool,
{
ExtractIf {
f,
inner: RawExtractIf {
iter: unsafe { self.table.iter() },
table: &mut self.table,
},
}
}
/// Clears the map, removing all key-value pairs. Keeps the allocated memory
/// for reuse.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut a = HashMap::new();
/// a.insert(1, "a");
/// let capacity_before_clear = a.capacity();
///
/// a.clear();
///
/// // Map is empty.
/// assert!(a.is_empty());
/// // But map capacity is equal to old one.
/// assert_eq!(a.capacity(), capacity_before_clear);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn clear(&mut self) {
self.table.clear();
}
/// Creates a consuming iterator visiting all the keys in arbitrary order.
/// The map cannot be used after calling this.
/// The iterator element type is `K`.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// map.insert("a", 1);
/// map.insert("b", 2);
/// map.insert("c", 3);
///
/// let mut vec: Vec<&str> = map.into_keys().collect();
///
/// // The `IntoKeys` iterator produces keys in arbitrary order, so the
/// // keys must be sorted to test them against a sorted array.
/// vec.sort_unstable();
/// assert_eq!(vec, ["a", "b", "c"]);
/// ```
#[inline]
pub fn into_keys(self) -> IntoKeys<K, V, A> {
IntoKeys {
inner: self.into_iter(),
}
}
/// Creates a consuming iterator visiting all the values in arbitrary order.
/// The map cannot be used after calling this.
/// The iterator element type is `V`.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// map.insert("a", 1);
/// map.insert("b", 2);
/// map.insert("c", 3);
///
/// let mut vec: Vec<i32> = map.into_values().collect();
///
/// // The `IntoValues` iterator produces values in arbitrary order, so
/// // the values must be sorted to test them against a sorted array.
/// vec.sort_unstable();
/// assert_eq!(vec, [1, 2, 3]);
/// ```
#[inline]
pub fn into_values(self) -> IntoValues<K, V, A> {
IntoValues {
inner: self.into_iter(),
}
}
}
impl<K, V, S, A> HashMap<K, V, S, A>
where
K: Eq + Hash,
S: BuildHasher,
A: Allocator,
{
/// Reserves capacity for at least `additional` more elements to be inserted
/// in the `HashMap`. The collection may reserve more space to avoid
/// frequent reallocations.
///
/// # Panics
///
/// Panics if the new capacity exceeds [`isize::MAX`] bytes and [`abort`] the program
/// in case of allocation error. Use [`try_reserve`](HashMap::try_reserve) instead
/// if you want to handle memory allocation failure.
///
/// [`isize::MAX`]: https://doc.rust-lang.org/std/primitive.isize.html
/// [`abort`]: https://doc.rust-lang.org/alloc/alloc/fn.handle_alloc_error.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
/// let mut map: HashMap<&str, i32> = HashMap::new();
/// // Map is empty and doesn't allocate memory
/// assert_eq!(map.capacity(), 0);
///
/// map.reserve(10);
///
/// // And now map can hold at least 10 elements
/// assert!(map.capacity() >= 10);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn reserve(&mut self, additional: usize) {
self.table
.reserve(additional, make_hasher::<_, V, S>(&self.hash_builder));
}
/// Tries to reserve capacity for at least `additional` more elements to be inserted
/// in the given `HashMap<K,V>`. The collection may reserve more space to avoid
/// frequent reallocations.
///
/// # Errors
///
/// If the capacity overflows, or the allocator reports a failure, then an error
/// is returned.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map: HashMap<&str, isize> = HashMap::new();
/// // Map is empty and doesn't allocate memory
/// assert_eq!(map.capacity(), 0);
///
/// map.try_reserve(10).expect("why is the test harness OOMing on 10 bytes?");
///
/// // And now map can hold at least 10 elements
/// assert!(map.capacity() >= 10);
/// ```
/// If the capacity overflows, or the allocator reports a failure, then an error
/// is returned:
/// ```
/// # fn test() {
/// use hashbrown::HashMap;
/// use hashbrown::TryReserveError;
/// let mut map: HashMap<i32, i32> = HashMap::new();
///
/// match map.try_reserve(usize::MAX) {
/// Err(error) => match error {
/// TryReserveError::CapacityOverflow => {}
/// _ => panic!("TryReserveError::AllocError ?"),
/// },
/// _ => panic!(),
/// }
/// # }
/// # fn main() {
/// # #[cfg(not(miri))]
/// # test()
/// # }
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
self.table
.try_reserve(additional, make_hasher::<_, V, S>(&self.hash_builder))
}
/// Shrinks the capacity of the map 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 hashbrown::HashMap;
///
/// let mut map: HashMap<i32, i32> = HashMap::with_capacity(100);
/// map.insert(1, 2);
/// map.insert(3, 4);
/// assert!(map.capacity() >= 100);
/// map.shrink_to_fit();
/// assert!(map.capacity() >= 2);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn shrink_to_fit(&mut self) {
self.table
.shrink_to(0, make_hasher::<_, V, S>(&self.hash_builder));
}
/// Shrinks the capacity of the map 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.
///
/// This function does nothing if the current capacity is smaller than the
/// supplied minimum capacity.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map: HashMap<i32, i32> = HashMap::with_capacity(100);
/// map.insert(1, 2);
/// map.insert(3, 4);
/// assert!(map.capacity() >= 100);
/// map.shrink_to(10);
/// assert!(map.capacity() >= 10);
/// map.shrink_to(0);
/// assert!(map.capacity() >= 2);
/// map.shrink_to(10);
/// assert!(map.capacity() >= 2);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn shrink_to(&mut self, min_capacity: usize) {
self.table
.shrink_to(min_capacity, make_hasher::<_, V, S>(&self.hash_builder));
}
/// Gets the given key's corresponding entry in the map for in-place manipulation.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut letters = HashMap::new();
///
/// for ch in "a short treatise on fungi".chars() {
/// let counter = letters.entry(ch).or_insert(0);
/// *counter += 1;
/// }
///
/// assert_eq!(letters[&'s'], 2);
/// assert_eq!(letters[&'t'], 3);
/// assert_eq!(letters[&'u'], 1);
/// assert_eq!(letters.get(&'y'), None);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn entry(&mut self, key: K) -> Entry<'_, K, V, S, A> {
let hash = make_hash::<K, S>(&self.hash_builder, &key);
if let Some(elem) = self.table.find(hash, equivalent_key(&key)) {
Entry::Occupied(OccupiedEntry {
hash,
key: Some(key),
elem,
table: self,
})
} else {
Entry::Vacant(VacantEntry {
hash,
key,
table: self,
})
}
}
/// Gets the given key's corresponding entry by reference in the map for in-place manipulation.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut words: HashMap<String, usize> = HashMap::new();
/// let source = ["poneyland", "horseyland", "poneyland", "poneyland"];
/// for (i, &s) in source.iter().enumerate() {
/// let counter = words.entry_ref(s).or_insert(0);
/// *counter += 1;
/// }
///
/// assert_eq!(words["poneyland"], 3);
/// assert_eq!(words["horseyland"], 1);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn entry_ref<'a, 'b, Q: ?Sized>(&'a mut self, key: &'b Q) -> EntryRef<'a, 'b, K, Q, V, S, A>
where
Q: Hash + Equivalent<K>,
{
let hash = make_hash::<Q, S>(&self.hash_builder, key);
if let Some(elem) = self.table.find(hash, equivalent_key(key)) {
EntryRef::Occupied(OccupiedEntryRef {
hash,
key: Some(KeyOrRef::Borrowed(key)),
elem,
table: self,
})
} else {
EntryRef::Vacant(VacantEntryRef {
hash,
key: KeyOrRef::Borrowed(key),
table: self,
})
}
}
/// Returns a reference to the value corresponding to the key.
///
/// The 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.
///
/// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
/// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// map.insert(1, "a");
/// assert_eq!(map.get(&1), Some(&"a"));
/// assert_eq!(map.get(&2), None);
/// ```
#[inline]
pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V>
where
Q: Hash + Equivalent<K>,
{
// Avoid `Option::map` because it bloats LLVM IR.
match self.get_inner(k) {
Some((_, v)) => Some(v),
None => None,
}
}
/// Returns the key-value pair corresponding to the supplied key.
///
/// 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.
///
/// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
/// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// map.insert(1, "a");
/// assert_eq!(map.get_key_value(&1), Some((&1, &"a")));
/// assert_eq!(map.get_key_value(&2), None);
/// ```
#[inline]
pub fn get_key_value<Q: ?Sized>(&self, k: &Q) -> Option<(&K, &V)>
where
Q: Hash + Equivalent<K>,
{
// Avoid `Option::map` because it bloats LLVM IR.
match self.get_inner(k) {
Some((key, value)) => Some((key, value)),
None => None,
}
}
#[inline]
fn get_inner<Q: ?Sized>(&self, k: &Q) -> Option<&(K, V)>
where
Q: Hash + Equivalent<K>,
{
if self.table.is_empty() {
None
} else {
let hash = make_hash::<Q, S>(&self.hash_builder, k);
self.table.get(hash, equivalent_key(k))
}
}
/// Returns the key-value pair corresponding to the supplied key, with a mutable reference to value.
///
/// 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.
///
/// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
/// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// map.insert(1, "a");
/// let (k, v) = map.get_key_value_mut(&1).unwrap();
/// assert_eq!(k, &1);
/// assert_eq!(v, &mut "a");
/// *v = "b";
/// assert_eq!(map.get_key_value_mut(&1), Some((&1, &mut "b")));
/// assert_eq!(map.get_key_value_mut(&2), None);
/// ```
#[inline]
pub fn get_key_value_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<(&K, &mut V)>
where
Q: Hash + Equivalent<K>,
{
// Avoid `Option::map` because it bloats LLVM IR.
match self.get_inner_mut(k) {
Some(&mut (ref key, ref mut value)) => Some((key, value)),
None => None,
}
}
/// 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, but
/// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
/// the key type.
///
/// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
/// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// map.insert(1, "a");
/// assert_eq!(map.contains_key(&1), true);
/// assert_eq!(map.contains_key(&2), false);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn contains_key<Q: ?Sized>(&self, k: &Q) -> bool
where
Q: Hash + Equivalent<K>,
{
self.get_inner(k).is_some()
}
/// Returns a mutable reference to the value corresponding to the key.
///
/// The 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.
///
/// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
/// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// map.insert(1, "a");
/// if let Some(x) = map.get_mut(&1) {
/// *x = "b";
/// }
/// assert_eq!(map[&1], "b");
///
/// assert_eq!(map.get_mut(&2), None);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut V>
where
Q: Hash + Equivalent<K>,
{
// Avoid `Option::map` because it bloats LLVM IR.
match self.get_inner_mut(k) {
Some(&mut (_, ref mut v)) => Some(v),
None => None,
}
}
#[inline]
fn get_inner_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut (K, V)>
where
Q: Hash + Equivalent<K>,
{
if self.table.is_empty() {
None
} else {
let hash = make_hash::<Q, S>(&self.hash_builder, k);
self.table.get_mut(hash, equivalent_key(k))
}
}
/// Attempts to get mutable references to `N` values in the map at once.
///
/// Returns an array of length `N` with the results of each query. For soundness, at most one
/// mutable reference will be returned to any value. `None` will be returned if any of the
/// keys are duplicates or missing.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut libraries = HashMap::new();
/// libraries.insert("Bodleian Library".to_string(), 1602);
/// libraries.insert("Athenæum".to_string(), 1807);
/// libraries.insert("Herzogin-Anna-Amalia-Bibliothek".to_string(), 1691);
/// libraries.insert("Library of Congress".to_string(), 1800);
///
/// let got = libraries.get_many_mut([
/// "Athenæum",
/// "Library of Congress",
/// ]);
/// assert_eq!(
/// got,
/// Some([
/// &mut 1807,
/// &mut 1800,
/// ]),
/// );
///
/// // Missing keys result in None
/// let got = libraries.get_many_mut([
/// "Athenæum",
/// "New York Public Library",
/// ]);
/// assert_eq!(got, None);
///
/// // Duplicate keys result in None
/// let got = libraries.get_many_mut([
/// "Athenæum",
/// "Athenæum",
/// ]);
/// assert_eq!(got, None);
/// ```
pub fn get_many_mut<Q: ?Sized, const N: usize>(&mut self, ks: [&Q; N]) -> Option<[&'_ mut V; N]>
where
Q: Hash + Equivalent<K>,
{
self.get_many_mut_inner(ks).map(|res| res.map(|(_, v)| v))
}
/// Attempts to get mutable references to `N` values in the map at once, without validating that
/// the values are unique.
///
/// Returns an array of length `N` with the results of each query. `None` will be returned if
/// any of the keys are missing.
///
/// For a safe alternative see [`get_many_mut`](`HashMap::get_many_mut`).
///
/// # Safety
///
/// Calling this method with overlapping keys is *[undefined behavior]* even if the resulting
/// references are not used.
///
/// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut libraries = HashMap::new();
/// libraries.insert("Bodleian Library".to_string(), 1602);
/// libraries.insert("Athenæum".to_string(), 1807);
/// libraries.insert("Herzogin-Anna-Amalia-Bibliothek".to_string(), 1691);
/// libraries.insert("Library of Congress".to_string(), 1800);
///
/// let got = libraries.get_many_mut([
/// "Athenæum",
/// "Library of Congress",
/// ]);
/// assert_eq!(
/// got,
/// Some([
/// &mut 1807,
/// &mut 1800,
/// ]),
/// );
///
/// // Missing keys result in None
/// let got = libraries.get_many_mut([
/// "Athenæum",
/// "New York Public Library",
/// ]);
/// assert_eq!(got, None);
/// ```
pub unsafe fn get_many_unchecked_mut<Q: ?Sized, const N: usize>(
&mut self,
ks: [&Q; N],
) -> Option<[&'_ mut V; N]>
where
Q: Hash + Equivalent<K>,
{
self.get_many_unchecked_mut_inner(ks)
.map(|res| res.map(|(_, v)| v))
}
/// Attempts to get mutable references to `N` values in the map at once, with immutable
/// references to the corresponding keys.
///
/// Returns an array of length `N` with the results of each query. For soundness, at most one
/// mutable reference will be returned to any value. `None` will be returned if any of the keys
/// are duplicates or missing.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut libraries = HashMap::new();
/// libraries.insert("Bodleian Library".to_string(), 1602);
/// libraries.insert("Athenæum".to_string(), 1807);
/// libraries.insert("Herzogin-Anna-Amalia-Bibliothek".to_string(), 1691);
/// libraries.insert("Library of Congress".to_string(), 1800);
///
/// let got = libraries.get_many_key_value_mut([
/// "Bodleian Library",
/// "Herzogin-Anna-Amalia-Bibliothek",
/// ]);
/// assert_eq!(
/// got,
/// Some([
/// (&"Bodleian Library".to_string(), &mut 1602),
/// (&"Herzogin-Anna-Amalia-Bibliothek".to_string(), &mut 1691),
/// ]),
/// );
/// // Missing keys result in None
/// let got = libraries.get_many_key_value_mut([
/// "Bodleian Library",
/// "Gewandhaus",
/// ]);
/// assert_eq!(got, None);
///
/// // Duplicate keys result in None
/// let got = libraries.get_many_key_value_mut([
/// "Bodleian Library",
/// "Herzogin-Anna-Amalia-Bibliothek",
/// "Herzogin-Anna-Amalia-Bibliothek",
/// ]);
/// assert_eq!(got, None);
/// ```
pub fn get_many_key_value_mut<Q: ?Sized, const N: usize>(
&mut self,
ks: [&Q; N],
) -> Option<[(&'_ K, &'_ mut V); N]>
where
Q: Hash + Equivalent<K>,
{
self.get_many_mut_inner(ks)
.map(|res| res.map(|(k, v)| (&*k, v)))
}
/// Attempts to get mutable references to `N` values in the map at once, with immutable
/// references to the corresponding keys, without validating that the values are unique.
///
/// Returns an array of length `N` with the results of each query. `None` will be returned if
/// any of the keys are missing.
///
/// For a safe alternative see [`get_many_key_value_mut`](`HashMap::get_many_key_value_mut`).
///
/// # Safety
///
/// Calling this method with overlapping keys is *[undefined behavior]* even if the resulting
/// references are not used.
///
/// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut libraries = HashMap::new();
/// libraries.insert("Bodleian Library".to_string(), 1602);
/// libraries.insert("Athenæum".to_string(), 1807);
/// libraries.insert("Herzogin-Anna-Amalia-Bibliothek".to_string(), 1691);
/// libraries.insert("Library of Congress".to_string(), 1800);
///
/// let got = libraries.get_many_key_value_mut([
/// "Bodleian Library",
/// "Herzogin-Anna-Amalia-Bibliothek",
/// ]);
/// assert_eq!(
/// got,
/// Some([
/// (&"Bodleian Library".to_string(), &mut 1602),
/// (&"Herzogin-Anna-Amalia-Bibliothek".to_string(), &mut 1691),
/// ]),
/// );
/// // Missing keys result in None
/// let got = libraries.get_many_key_value_mut([
/// "Bodleian Library",
/// "Gewandhaus",
/// ]);
/// assert_eq!(got, None);
/// ```
pub unsafe fn get_many_key_value_unchecked_mut<Q: ?Sized, const N: usize>(
&mut self,
ks: [&Q; N],
) -> Option<[(&'_ K, &'_ mut V); N]>
where
Q: Hash + Equivalent<K>,
{
self.get_many_unchecked_mut_inner(ks)
.map(|res| res.map(|(k, v)| (&*k, v)))
}
fn get_many_mut_inner<Q: ?Sized, const N: usize>(
&mut self,
ks: [&Q; N],
) -> Option<[&'_ mut (K, V); N]>
where
Q: Hash + Equivalent<K>,
{
let hashes = self.build_hashes_inner(ks);
self.table
.get_many_mut(hashes, |i, (k, _)| ks[i].equivalent(k))
}
unsafe fn get_many_unchecked_mut_inner<Q: ?Sized, const N: usize>(
&mut self,
ks: [&Q; N],
) -> Option<[&'_ mut (K, V); N]>
where
Q: Hash + Equivalent<K>,
{
let hashes = self.build_hashes_inner(ks);
self.table
.get_many_unchecked_mut(hashes, |i, (k, _)| ks[i].equivalent(k))
}
fn build_hashes_inner<Q: ?Sized, const N: usize>(&self, ks: [&Q; N]) -> [u64; N]
where
Q: Hash + Equivalent<K>,
{
let mut hashes = [0_u64; N];
for i in 0..N {
hashes[i] = make_hash::<Q, S>(&self.hash_builder, ks[i]);
}
hashes
}
/// Inserts a key-value pair into the map.
///
/// If the map did not have this key present, [`None`] is returned.
///
/// If the map did have this key present, the value is updated, and the old
/// value is returned. The key is not updated, though; this matters for
/// types that can be `==` without being identical. See the [`std::collections`]
/// [module-level documentation] for more.
///
/// [`None`]: https://doc.rust-lang.org/std/option/enum.Option.html#variant.None
/// [`std::collections`]: https://doc.rust-lang.org/std/collections/index.html
/// [module-level documentation]: https://doc.rust-lang.org/std/collections/index.html#insert-and-complex-keys
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// assert_eq!(map.insert(37, "a"), None);
/// assert_eq!(map.is_empty(), false);
///
/// map.insert(37, "b");
/// assert_eq!(map.insert(37, "c"), Some("b"));
/// assert_eq!(map[&37], "c");
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn insert(&mut self, k: K, v: V) -> Option<V> {
let hash = make_hash::<K, S>(&self.hash_builder, &k);
let hasher = make_hasher::<_, V, S>(&self.hash_builder);
match self
.table
.find_or_find_insert_slot(hash, equivalent_key(&k), hasher)
{
Ok(bucket) => Some(mem::replace(unsafe { &mut bucket.as_mut().1 }, v)),
Err(slot) => {
unsafe {
self.table.insert_in_slot(hash, slot, (k, v));
}
None
}
}
}
/// Insert a key-value pair into the map without checking
/// if the key already exists in the map.
///
/// Returns a reference to the key and value just inserted.
///
/// This operation is safe if a key does not exist in the map.
///
/// However, if a key exists in the map already, the behavior is unspecified:
/// this operation may panic, loop forever, or any following operation with the map
/// may panic, loop forever or return arbitrary result.
///
/// That said, this operation (and following operations) are guaranteed to
/// not violate memory safety.
///
/// This operation is faster than regular insert, because it does not perform
/// lookup before insertion.
///
/// This operation is useful during initial population of the map.
/// For example, when constructing a map from another map, we know
/// that keys are unique.
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map1 = HashMap::new();
/// assert_eq!(map1.insert(1, "a"), None);
/// assert_eq!(map1.insert(2, "b"), None);
/// assert_eq!(map1.insert(3, "c"), None);
/// assert_eq!(map1.len(), 3);
///
/// let mut map2 = HashMap::new();
///
/// for (key, value) in map1.into_iter() {
/// map2.insert_unique_unchecked(key, value);
/// }
///
/// let (key, value) = map2.insert_unique_unchecked(4, "d");
/// assert_eq!(key, &4);
/// assert_eq!(value, &mut "d");
/// *value = "e";
///
/// assert_eq!(map2[&1], "a");
/// assert_eq!(map2[&2], "b");
/// assert_eq!(map2[&3], "c");
/// assert_eq!(map2[&4], "e");
/// assert_eq!(map2.len(), 4);
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn insert_unique_unchecked(&mut self, k: K, v: V) -> (&K, &mut V) {
let hash = make_hash::<K, S>(&self.hash_builder, &k);
let bucket = self
.table
.insert(hash, (k, v), make_hasher::<_, V, S>(&self.hash_builder));
let (k_ref, v_ref) = unsafe { bucket.as_mut() };
(k_ref, v_ref)
}
/// Tries to insert a key-value pair into the map, and returns
/// a mutable reference to the value in the entry.
///
/// # Errors
///
/// If the map already had this key present, nothing is updated, and
/// an error containing the occupied entry and the value is returned.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// use hashbrown::HashMap;
/// use hashbrown::hash_map::OccupiedError;
///
/// let mut map = HashMap::new();
/// assert_eq!(map.try_insert(37, "a").unwrap(), &"a");
///
/// match map.try_insert(37, "b") {
/// Err(OccupiedError { entry, value }) => {
/// assert_eq!(entry.key(), &37);
/// assert_eq!(entry.get(), &"a");
/// assert_eq!(value, "b");
/// }
/// _ => panic!()
/// }
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn try_insert(
&mut self,
key: K,
value: V,
) -> Result<&mut V, OccupiedError<'_, K, V, S, A>> {
match self.entry(key) {
Entry::Occupied(entry) => Err(OccupiedError { entry, value }),
Entry::Vacant(entry) => Ok(entry.insert(value)),
}
}
/// Removes a key from the map, returning the value at the key if the key
/// was previously in the map. Keeps the allocated memory for reuse.
///
/// The 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.
///
/// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
/// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// // The map is empty
/// assert!(map.is_empty() && map.capacity() == 0);
///
/// map.insert(1, "a");
///
/// assert_eq!(map.remove(&1), Some("a"));
/// assert_eq!(map.remove(&1), None);
///
/// // Now map holds none elements
/// assert!(map.is_empty());
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V>
where
Q: Hash + Equivalent<K>,
{
// Avoid `Option::map` because it bloats LLVM IR.
match self.remove_entry(k) {
Some((_, v)) => Some(v),
None => None,
}
}
/// Removes a key from the map, returning the stored key and value if the
/// key was previously in the map. Keeps the allocated memory for reuse.
///
/// The 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.
///
/// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
/// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
///
/// # Examples
///
/// ```
/// use hashbrown::HashMap;
///
/// let mut map = HashMap::new();
/// // The map is empty
/// assert!(map.is_empty() && map.capacity() == 0);
///
/// map.insert(1, "a");
///
/// assert_eq!(map.remove_entry(&1), Some((1, "a")));
/// assert_eq!(map.remove(&1), None);
///
/// // Now map hold none elements
/// assert!(map.is_empty());
/// ```
#[cfg_attr(feature = "inline-more", inline)]
pub fn remove_entry<Q: ?Sized>(&mut self, k: &Q) -> Option<(K, V)>
where
Q: Hash + Equivalent<K>,
{
let hash = make_hash::<Q, S>(&self.hash_builder, k);
self.table.remove_entry(hash, equivalent_key(k))
}
}
impl<K, V, S, A: Allocator> HashMap<K, V, S, A> {
/// Creates a raw entry builder for the HashMap.
///
/// Raw entries provide the lowest level of control for searching and
/// manipulating a map. They must be manually initialized with a hash and
/// then manually searched. After this, insertions into a vacant entry
/// still require an owned key to be provided.
///
--> --------------------
--> maximum size reached
--> --------------------
[ zur Elbe Produktseite wechseln0.43Quellennavigators
Analyse erneut starten
]
|
2026-04-02
|
|
|
|
|
