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+#[cfg(feature = "raw")]
+use crate::raw::RawTable;
+use crate::{Equivalent, TryReserveError};
+use alloc::borrow::ToOwned;
+use core::fmt;
+use core::hash::{BuildHasher, Hash};
+use core::iter::{Chain, FromIterator, FusedIterator};
+use core::ops::{BitAnd, BitOr, BitXor, Sub};
+
+use super::map::{self, DefaultHashBuilder, ExtractIfInner, HashMap, Keys};
+use crate::raw::{Allocator, Global};
+
+// Future Optimization (FIXME!)
+// =============================
+//
+// Iteration over zero sized values is a noop. There is no need
+// for `bucket.val` in the case of HashSet. I suppose we would need HKT
+// to get rid of it properly.
+
+/// A hash set implemented as a `HashMap` where the value is `()`.
+///
+/// As with the [`HashMap`] type, a `HashSet` requires that the elements
+/// 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:
+///
+/// ```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 an item to be modified in such a way that the
+/// item's hash, as determined by the [`Hash`] trait, or its equality, as
+/// determined by the [`Eq`] trait, changes while it is in the set. 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 `HashSet` may become corrupted and
+/// some items may be dropped from the table.
+///
+/// # Examples
+///
+/// ```
+/// use hashbrown::HashSet;
+/// // Type inference lets us omit an explicit type signature (which
+/// // would be `HashSet<String>` in this example).
+/// let mut books = HashSet::new();
+///
+/// // Add some books.
+/// books.insert("A Dance With Dragons".to_string());
+/// books.insert("To Kill a Mockingbird".to_string());
+/// books.insert("The Odyssey".to_string());
+/// books.insert("The Great Gatsby".to_string());
+///
+/// // Check for a specific one.
+/// if !books.contains("The Winds of Winter") {
+/// println!("We have {} books, but The Winds of Winter ain't one.",
+/// books.len());
+/// }
+///
+/// // Remove a book.
+/// books.remove("The Odyssey");
+///
+/// // Iterate over everything.
+/// for book in &books {
+/// println!("{}", book);
+/// }
+/// ```
+///
+/// The easiest way to use `HashSet` with a custom type is to derive
+/// [`Eq`] and [`Hash`]. We must also derive [`PartialEq`]. This will in the
+/// future be implied by [`Eq`].
+///
+/// ```
+/// use hashbrown::HashSet;
+/// #[derive(Hash, Eq, PartialEq, Debug)]
+/// struct Viking {
+/// name: String,
+/// power: usize,
+/// }
+///
+/// let mut vikings = HashSet::new();
+///
+/// vikings.insert(Viking { name: "Einar".to_string(), power: 9 });
+/// vikings.insert(Viking { name: "Einar".to_string(), power: 9 });
+/// vikings.insert(Viking { name: "Olaf".to_string(), power: 4 });
+/// vikings.insert(Viking { name: "Harald".to_string(), power: 8 });
+///
+/// // Use derived implementation to print the vikings.
+/// for x in &vikings {
+/// println!("{:?}", x);
+/// }
+/// ```
+///
+/// A `HashSet` with fixed list of elements can be initialized from an array:
+///
+/// ```
+/// use hashbrown::HashSet;
+///
+/// let viking_names: HashSet<&'static str> =
+/// [ "Einar", "Olaf", "Harald" ].iter().cloned().collect();
+/// // use the values stored in the set
+/// ```
+///
+/// [`Cell`]: https://doc.rust-lang.org/std/cell/struct.Cell.html
+/// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
+/// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
+/// [`HashMap`]: struct.HashMap.html
+/// [`PartialEq`]: https://doc.rust-lang.org/std/cmp/trait.PartialEq.html
+/// [`RefCell`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html
+pub struct HashSet<T, S = DefaultHashBuilder, A: Allocator = Global> {
+ pub(crate) map: HashMap<T, (), S, A>,
+}
+
+impl<T: Clone, S: Clone, A: Allocator + Clone> Clone for HashSet<T, S, A> {
+ fn clone(&self) -> Self {
+ HashSet {
+ map: self.map.clone(),
+ }
+ }
+
+ fn clone_from(&mut self, source: &Self) {
+ self.map.clone_from(&source.map);
+ }
+}
+
+#[cfg(feature = "ahash")]
+impl<T> HashSet<T, DefaultHashBuilder> {
+ /// Creates an empty `HashSet`.
+ ///
+ /// The hash set 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 `HashSet` 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 [`HashSet`], for example with
+ /// [`with_hasher`](HashSet::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::HashSet;
+ /// let set: HashSet<i32> = HashSet::new();
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn new() -> Self {
+ Self {
+ map: HashMap::new(),
+ }
+ }
+
+ /// Creates an empty `HashSet` with the specified capacity.
+ ///
+ /// The hash set will be able to hold at least `capacity` elements without
+ /// reallocating. If `capacity` is 0, the hash set will not allocate.
+ ///
+ /// # HashDoS resistance
+ ///
+ /// The `hash_builder` normally use a fixed key by default and that does
+ /// not allow the `HashSet` 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 [`HashSet`], for example with
+ /// [`with_capacity_and_hasher`](HashSet::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::HashSet;
+ /// let set: HashSet<i32> = HashSet::with_capacity(10);
+ /// assert!(set.capacity() >= 10);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn with_capacity(capacity: usize) -> Self {
+ Self {
+ map: HashMap::with_capacity(capacity),
+ }
+ }
+}
+
+#[cfg(feature = "ahash")]
+impl<T: Hash + Eq, A: Allocator> HashSet<T, DefaultHashBuilder, A> {
+ /// Creates an empty `HashSet`.
+ ///
+ /// The hash set 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 `HashSet` 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 [`HashSet`], for example with
+ /// [`with_hasher_in`](HashSet::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::HashSet;
+ /// let set: HashSet<i32> = HashSet::new();
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn new_in(alloc: A) -> Self {
+ Self {
+ map: HashMap::new_in(alloc),
+ }
+ }
+
+ /// Creates an empty `HashSet` with the specified capacity.
+ ///
+ /// The hash set will be able to hold at least `capacity` elements without
+ /// reallocating. If `capacity` is 0, the hash set will not allocate.
+ ///
+ /// # HashDoS resistance
+ ///
+ /// The `hash_builder` normally use a fixed key by default and that does
+ /// not allow the `HashSet` 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 [`HashSet`], for example with
+ /// [`with_capacity_and_hasher_in`](HashSet::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::HashSet;
+ /// let set: HashSet<i32> = HashSet::with_capacity(10);
+ /// assert!(set.capacity() >= 10);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn with_capacity_in(capacity: usize, alloc: A) -> Self {
+ Self {
+ map: HashMap::with_capacity_in(capacity, alloc),
+ }
+ }
+}
+
+impl<T, S, A: Allocator> HashSet<T, S, A> {
+ /// Returns the number of elements the set can hold without reallocating.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ /// let set: HashSet<i32> = HashSet::with_capacity(100);
+ /// assert!(set.capacity() >= 100);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn capacity(&self) -> usize {
+ self.map.capacity()
+ }
+
+ /// An iterator visiting all elements in arbitrary order.
+ /// The iterator element type is `&'a T`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ /// let mut set = HashSet::new();
+ /// set.insert("a");
+ /// set.insert("b");
+ ///
+ /// // Will print in an arbitrary order.
+ /// for x in set.iter() {
+ /// println!("{}", x);
+ /// }
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn iter(&self) -> Iter<'_, T> {
+ Iter {
+ iter: self.map.keys(),
+ }
+ }
+
+ /// Returns the number of elements in the set.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut v = HashSet::new();
+ /// assert_eq!(v.len(), 0);
+ /// v.insert(1);
+ /// assert_eq!(v.len(), 1);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn len(&self) -> usize {
+ self.map.len()
+ }
+
+ /// Returns `true` if the set contains no elements.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut v = HashSet::new();
+ /// assert!(v.is_empty());
+ /// v.insert(1);
+ /// assert!(!v.is_empty());
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn is_empty(&self) -> bool {
+ self.map.is_empty()
+ }
+
+ /// Clears the set, returning all elements in an iterator.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set: HashSet<_> = [1, 2, 3].iter().cloned().collect();
+ /// assert!(!set.is_empty());
+ ///
+ /// // print 1, 2, 3 in an arbitrary order
+ /// for i in set.drain() {
+ /// println!("{}", i);
+ /// }
+ ///
+ /// assert!(set.is_empty());
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn drain(&mut self) -> Drain<'_, T, A> {
+ Drain {
+ iter: self.map.drain(),
+ }
+ }
+
+ /// Retains only the elements specified by the predicate.
+ ///
+ /// In other words, remove all elements `e` such that `f(&e)` returns `false`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let xs = [1,2,3,4,5,6];
+ /// let mut set: HashSet<i32> = xs.iter().cloned().collect();
+ /// set.retain(|&k| k % 2 == 0);
+ /// assert_eq!(set.len(), 3);
+ /// ```
+ pub fn retain<F>(&mut self, mut f: F)
+ where
+ F: FnMut(&T) -> bool,
+ {
+ self.map.retain(|k, _| f(k));
+ }
+
+ /// Drains elements which are true under the given predicate,
+ /// and returns an iterator over the removed items.
+ ///
+ /// In other words, move all elements `e` such that `f(&e)` returns `true` out
+ /// into another iterator.
+ ///
+ /// 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.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set: HashSet<i32> = (0..8).collect();
+ /// let drained: HashSet<i32> = set.extract_if(|v| v % 2 == 0).collect();
+ ///
+ /// let mut evens = drained.into_iter().collect::<Vec<_>>();
+ /// let mut odds = set.into_iter().collect::<Vec<_>>();
+ /// evens.sort();
+ /// odds.sort();
+ ///
+ /// assert_eq!(evens, vec![0, 2, 4, 6]);
+ /// assert_eq!(odds, vec![1, 3, 5, 7]);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn extract_if<F>(&mut self, f: F) -> ExtractIf<'_, T, F, A>
+ where
+ F: FnMut(&T) -> bool,
+ {
+ ExtractIf {
+ f,
+ inner: ExtractIfInner {
+ iter: unsafe { self.map.table.iter() },
+ table: &mut self.map.table,
+ },
+ }
+ }
+
+ /// Clears the set, removing all values.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut v = HashSet::new();
+ /// v.insert(1);
+ /// v.clear();
+ /// assert!(v.is_empty());
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn clear(&mut self) {
+ self.map.clear();
+ }
+}
+
+impl<T, S> HashSet<T, S, Global> {
+ /// Creates a new empty hash set which will use the given hasher to hash
+ /// keys.
+ ///
+ /// The hash set 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 `HashSet` 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 [`HashSet`].
+ ///
+ /// The `hash_builder` passed should implement the [`BuildHasher`] trait for
+ /// the HashSet 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::HashSet;
+ /// use hashbrown::hash_map::DefaultHashBuilder;
+ ///
+ /// let s = DefaultHashBuilder::default();
+ /// let mut set = HashSet::with_hasher(s);
+ /// set.insert(2);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub const fn with_hasher(hasher: S) -> Self {
+ Self {
+ map: HashMap::with_hasher(hasher),
+ }
+ }
+
+ /// Creates an empty `HashSet` with the specified capacity, using
+ /// `hasher` to hash the keys.
+ ///
+ /// The hash set will be able to hold at least `capacity` elements without
+ /// reallocating. If `capacity` is 0, the hash set will not allocate.
+ ///
+ /// # HashDoS resistance
+ ///
+ /// The `hash_builder` normally use a fixed key by default and that does
+ /// not allow the `HashSet` 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 [`HashSet`].
+ ///
+ /// The `hash_builder` passed should implement the [`BuildHasher`] trait for
+ /// the HashSet 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::HashSet;
+ /// use hashbrown::hash_map::DefaultHashBuilder;
+ ///
+ /// let s = DefaultHashBuilder::default();
+ /// let mut set = HashSet::with_capacity_and_hasher(10, s);
+ /// set.insert(1);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn with_capacity_and_hasher(capacity: usize, hasher: S) -> Self {
+ Self {
+ map: HashMap::with_capacity_and_hasher(capacity, hasher),
+ }
+ }
+}
+
+impl<T, S, A> HashSet<T, S, A>
+where
+ A: Allocator,
+{
+ /// Returns a reference to the underlying allocator.
+ #[inline]
+ pub fn allocator(&self) -> &A {
+ self.map.allocator()
+ }
+
+ /// Creates a new empty hash set which will use the given hasher to hash
+ /// keys.
+ ///
+ /// The hash set 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 `HashSet` 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 [`HashSet`].
+ ///
+ /// The `hash_builder` passed should implement the [`BuildHasher`] trait for
+ /// the HashSet 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::HashSet;
+ /// use hashbrown::hash_map::DefaultHashBuilder;
+ ///
+ /// let s = DefaultHashBuilder::default();
+ /// let mut set = HashSet::with_hasher(s);
+ /// set.insert(2);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub const fn with_hasher_in(hasher: S, alloc: A) -> Self {
+ Self {
+ map: HashMap::with_hasher_in(hasher, alloc),
+ }
+ }
+
+ /// Creates an empty `HashSet` with the specified capacity, using
+ /// `hasher` to hash the keys.
+ ///
+ /// The hash set will be able to hold at least `capacity` elements without
+ /// reallocating. If `capacity` is 0, the hash set will not allocate.
+ ///
+ /// # HashDoS resistance
+ ///
+ /// The `hash_builder` normally use a fixed key by default and that does
+ /// not allow the `HashSet` 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 [`HashSet`].
+ ///
+ /// The `hash_builder` passed should implement the [`BuildHasher`] trait for
+ /// the HashSet 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::HashSet;
+ /// use hashbrown::hash_map::DefaultHashBuilder;
+ ///
+ /// let s = DefaultHashBuilder::default();
+ /// let mut set = HashSet::with_capacity_and_hasher(10, s);
+ /// set.insert(1);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn with_capacity_and_hasher_in(capacity: usize, hasher: S, alloc: A) -> Self {
+ Self {
+ map: HashMap::with_capacity_and_hasher_in(capacity, hasher, alloc),
+ }
+ }
+
+ /// Returns a reference to the set's [`BuildHasher`].
+ ///
+ /// [`BuildHasher`]: https://doc.rust-lang.org/std/hash/trait.BuildHasher.html
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ /// use hashbrown::hash_map::DefaultHashBuilder;
+ ///
+ /// let hasher = DefaultHashBuilder::default();
+ /// let set: HashSet<i32> = HashSet::with_hasher(hasher);
+ /// let hasher: &DefaultHashBuilder = set.hasher();
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn hasher(&self) -> &S {
+ self.map.hasher()
+ }
+}
+
+impl<T, S, A> HashSet<T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+ /// Reserves capacity for at least `additional` more elements to be inserted
+ /// in the `HashSet`. 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`](HashSet::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::HashSet;
+ /// let mut set: HashSet<i32> = HashSet::new();
+ /// set.reserve(10);
+ /// assert!(set.capacity() >= 10);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn reserve(&mut self, additional: usize) {
+ self.map.reserve(additional);
+ }
+
+ /// Tries to reserve capacity for at least `additional` more elements to be inserted
+ /// in the given `HashSet<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::HashSet;
+ /// let mut set: HashSet<i32> = HashSet::new();
+ /// set.try_reserve(10).expect("why is the test harness OOMing on 10 bytes?");
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
+ self.map.try_reserve(additional)
+ }
+
+ /// Shrinks the capacity of the set 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::HashSet;
+ ///
+ /// let mut set = HashSet::with_capacity(100);
+ /// set.insert(1);
+ /// set.insert(2);
+ /// assert!(set.capacity() >= 100);
+ /// set.shrink_to_fit();
+ /// assert!(set.capacity() >= 2);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn shrink_to_fit(&mut self) {
+ self.map.shrink_to_fit();
+ }
+
+ /// Shrinks the capacity of the set 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.
+ ///
+ /// Panics if the current capacity is smaller than the supplied
+ /// minimum capacity.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set = HashSet::with_capacity(100);
+ /// set.insert(1);
+ /// set.insert(2);
+ /// assert!(set.capacity() >= 100);
+ /// set.shrink_to(10);
+ /// assert!(set.capacity() >= 10);
+ /// set.shrink_to(0);
+ /// assert!(set.capacity() >= 2);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn shrink_to(&mut self, min_capacity: usize) {
+ self.map.shrink_to(min_capacity);
+ }
+
+ /// Visits the values representing the difference,
+ /// i.e., the values that are in `self` but not in `other`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect();
+ /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect();
+ ///
+ /// // Can be seen as `a - b`.
+ /// for x in a.difference(&b) {
+ /// println!("{}", x); // Print 1
+ /// }
+ ///
+ /// let diff: HashSet<_> = a.difference(&b).collect();
+ /// assert_eq!(diff, [1].iter().collect());
+ ///
+ /// // Note that difference is not symmetric,
+ /// // and `b - a` means something else:
+ /// let diff: HashSet<_> = b.difference(&a).collect();
+ /// assert_eq!(diff, [4].iter().collect());
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn difference<'a>(&'a self, other: &'a Self) -> Difference<'a, T, S, A> {
+ Difference {
+ iter: self.iter(),
+ other,
+ }
+ }
+
+ /// Visits the values representing the symmetric difference,
+ /// i.e., the values that are in `self` or in `other` but not in both.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect();
+ /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect();
+ ///
+ /// // Print 1, 4 in arbitrary order.
+ /// for x in a.symmetric_difference(&b) {
+ /// println!("{}", x);
+ /// }
+ ///
+ /// let diff1: HashSet<_> = a.symmetric_difference(&b).collect();
+ /// let diff2: HashSet<_> = b.symmetric_difference(&a).collect();
+ ///
+ /// assert_eq!(diff1, diff2);
+ /// assert_eq!(diff1, [1, 4].iter().collect());
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn symmetric_difference<'a>(&'a self, other: &'a Self) -> SymmetricDifference<'a, T, S, A> {
+ SymmetricDifference {
+ iter: self.difference(other).chain(other.difference(self)),
+ }
+ }
+
+ /// Visits the values representing the intersection,
+ /// i.e., the values that are both in `self` and `other`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect();
+ /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect();
+ ///
+ /// // Print 2, 3 in arbitrary order.
+ /// for x in a.intersection(&b) {
+ /// println!("{}", x);
+ /// }
+ ///
+ /// let intersection: HashSet<_> = a.intersection(&b).collect();
+ /// assert_eq!(intersection, [2, 3].iter().collect());
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn intersection<'a>(&'a self, other: &'a Self) -> Intersection<'a, T, S, A> {
+ let (smaller, larger) = if self.len() <= other.len() {
+ (self, other)
+ } else {
+ (other, self)
+ };
+ Intersection {
+ iter: smaller.iter(),
+ other: larger,
+ }
+ }
+
+ /// Visits the values representing the union,
+ /// i.e., all the values in `self` or `other`, without duplicates.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect();
+ /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect();
+ ///
+ /// // Print 1, 2, 3, 4 in arbitrary order.
+ /// for x in a.union(&b) {
+ /// println!("{}", x);
+ /// }
+ ///
+ /// let union: HashSet<_> = a.union(&b).collect();
+ /// assert_eq!(union, [1, 2, 3, 4].iter().collect());
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn union<'a>(&'a self, other: &'a Self) -> Union<'a, T, S, A> {
+ // We'll iterate one set in full, and only the remaining difference from the other.
+ // Use the smaller set for the difference in order to reduce hash lookups.
+ let (smaller, larger) = if self.len() <= other.len() {
+ (self, other)
+ } else {
+ (other, self)
+ };
+ Union {
+ iter: larger.iter().chain(smaller.difference(larger)),
+ }
+ }
+
+ /// Returns `true` if the set contains a value.
+ ///
+ /// The value may be any borrowed form of the set's value type, but
+ /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
+ /// the value type.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let set: HashSet<_> = [1, 2, 3].iter().cloned().collect();
+ /// assert_eq!(set.contains(&1), true);
+ /// assert_eq!(set.contains(&4), false);
+ /// ```
+ ///
+ /// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
+ /// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool
+ where
+ Q: Hash + Equivalent<T>,
+ {
+ self.map.contains_key(value)
+ }
+
+ /// Returns a reference to the value in the set, if any, that is equal to the given value.
+ ///
+ /// The value may be any borrowed form of the set's value type, but
+ /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
+ /// the value type.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let set: HashSet<_> = [1, 2, 3].iter().cloned().collect();
+ /// assert_eq!(set.get(&2), Some(&2));
+ /// assert_eq!(set.get(&4), None);
+ /// ```
+ ///
+ /// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
+ /// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn get<Q: ?Sized>(&self, value: &Q) -> Option<&T>
+ where
+ Q: Hash + Equivalent<T>,
+ {
+ // Avoid `Option::map` because it bloats LLVM IR.
+ match self.map.get_key_value(value) {
+ Some((k, _)) => Some(k),
+ None => None,
+ }
+ }
+
+ /// Inserts the given `value` into the set if it is not present, then
+ /// returns a reference to the value in the set.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set: HashSet<_> = [1, 2, 3].iter().cloned().collect();
+ /// assert_eq!(set.len(), 3);
+ /// assert_eq!(set.get_or_insert(2), &2);
+ /// assert_eq!(set.get_or_insert(100), &100);
+ /// assert_eq!(set.len(), 4); // 100 was inserted
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn get_or_insert(&mut self, value: T) -> &T {
+ // Although the raw entry gives us `&mut T`, we only return `&T` to be consistent with
+ // `get`. Key mutation is "raw" because you're not supposed to affect `Eq` or `Hash`.
+ self.map
+ .raw_entry_mut()
+ .from_key(&value)
+ .or_insert(value, ())
+ .0
+ }
+
+ /// Inserts an owned copy of the given `value` into the set if it is not
+ /// present, then returns a reference to the value in the set.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set: HashSet<String> = ["cat", "dog", "horse"]
+ /// .iter().map(|&pet| pet.to_owned()).collect();
+ ///
+ /// assert_eq!(set.len(), 3);
+ /// for &pet in &["cat", "dog", "fish"] {
+ /// let value = set.get_or_insert_owned(pet);
+ /// assert_eq!(value, pet);
+ /// }
+ /// assert_eq!(set.len(), 4); // a new "fish" was inserted
+ /// ```
+ #[inline]
+ pub fn get_or_insert_owned<Q: ?Sized>(&mut self, value: &Q) -> &T
+ where
+ Q: Hash + Equivalent<T> + ToOwned<Owned = T>,
+ {
+ // Although the raw entry gives us `&mut T`, we only return `&T` to be consistent with
+ // `get`. Key mutation is "raw" because you're not supposed to affect `Eq` or `Hash`.
+ self.map
+ .raw_entry_mut()
+ .from_key(value)
+ .or_insert_with(|| (value.to_owned(), ()))
+ .0
+ }
+
+ /// Inserts a value computed from `f` into the set if the given `value` is
+ /// not present, then returns a reference to the value in the set.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set: HashSet<String> = ["cat", "dog", "horse"]
+ /// .iter().map(|&pet| pet.to_owned()).collect();
+ ///
+ /// assert_eq!(set.len(), 3);
+ /// for &pet in &["cat", "dog", "fish"] {
+ /// let value = set.get_or_insert_with(pet, str::to_owned);
+ /// assert_eq!(value, pet);
+ /// }
+ /// assert_eq!(set.len(), 4); // a new "fish" was inserted
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn get_or_insert_with<Q: ?Sized, F>(&mut self, value: &Q, f: F) -> &T
+ where
+ Q: Hash + Equivalent<T>,
+ F: FnOnce(&Q) -> T,
+ {
+ // Although the raw entry gives us `&mut T`, we only return `&T` to be consistent with
+ // `get`. Key mutation is "raw" because you're not supposed to affect `Eq` or `Hash`.
+ self.map
+ .raw_entry_mut()
+ .from_key(value)
+ .or_insert_with(|| (f(value), ()))
+ .0
+ }
+
+ /// Gets the given value's corresponding entry in the set for in-place manipulation.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ /// use hashbrown::hash_set::Entry::*;
+ ///
+ /// let mut singles = HashSet::new();
+ /// let mut dupes = HashSet::new();
+ ///
+ /// for ch in "a short treatise on fungi".chars() {
+ /// if let Vacant(dupe_entry) = dupes.entry(ch) {
+ /// // We haven't already seen a duplicate, so
+ /// // check if we've at least seen it once.
+ /// match singles.entry(ch) {
+ /// Vacant(single_entry) => {
+ /// // We found a new character for the first time.
+ /// single_entry.insert()
+ /// }
+ /// Occupied(single_entry) => {
+ /// // We've already seen this once, "move" it to dupes.
+ /// single_entry.remove();
+ /// dupe_entry.insert();
+ /// }
+ /// }
+ /// }
+ /// }
+ ///
+ /// assert!(!singles.contains(&'t') && dupes.contains(&'t'));
+ /// assert!(singles.contains(&'u') && !dupes.contains(&'u'));
+ /// assert!(!singles.contains(&'v') && !dupes.contains(&'v'));
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn entry(&mut self, value: T) -> Entry<'_, T, S, A> {
+ match self.map.entry(value) {
+ map::Entry::Occupied(entry) => Entry::Occupied(OccupiedEntry { inner: entry }),
+ map::Entry::Vacant(entry) => Entry::Vacant(VacantEntry { inner: entry }),
+ }
+ }
+
+ /// Returns `true` if `self` has no elements in common with `other`.
+ /// This is equivalent to checking for an empty intersection.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect();
+ /// let mut b = HashSet::new();
+ ///
+ /// assert_eq!(a.is_disjoint(&b), true);
+ /// b.insert(4);
+ /// assert_eq!(a.is_disjoint(&b), true);
+ /// b.insert(1);
+ /// assert_eq!(a.is_disjoint(&b), false);
+ /// ```
+ pub fn is_disjoint(&self, other: &Self) -> bool {
+ self.iter().all(|v| !other.contains(v))
+ }
+
+ /// Returns `true` if the set is a subset of another,
+ /// i.e., `other` contains at least all the values in `self`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let sup: HashSet<_> = [1, 2, 3].iter().cloned().collect();
+ /// let mut set = HashSet::new();
+ ///
+ /// assert_eq!(set.is_subset(&sup), true);
+ /// set.insert(2);
+ /// assert_eq!(set.is_subset(&sup), true);
+ /// set.insert(4);
+ /// assert_eq!(set.is_subset(&sup), false);
+ /// ```
+ pub fn is_subset(&self, other: &Self) -> bool {
+ self.len() <= other.len() && self.iter().all(|v| other.contains(v))
+ }
+
+ /// Returns `true` if the set is a superset of another,
+ /// i.e., `self` contains at least all the values in `other`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let sub: HashSet<_> = [1, 2].iter().cloned().collect();
+ /// let mut set = HashSet::new();
+ ///
+ /// assert_eq!(set.is_superset(&sub), false);
+ ///
+ /// set.insert(0);
+ /// set.insert(1);
+ /// assert_eq!(set.is_superset(&sub), false);
+ ///
+ /// set.insert(2);
+ /// assert_eq!(set.is_superset(&sub), true);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn is_superset(&self, other: &Self) -> bool {
+ other.is_subset(self)
+ }
+
+ /// Adds a value to the set.
+ ///
+ /// If the set did not have this value present, `true` is returned.
+ ///
+ /// If the set did have this value present, `false` is returned.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set = HashSet::new();
+ ///
+ /// assert_eq!(set.insert(2), true);
+ /// assert_eq!(set.insert(2), false);
+ /// assert_eq!(set.len(), 1);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn insert(&mut self, value: T) -> bool {
+ self.map.insert(value, ()).is_none()
+ }
+
+ /// Insert a value the set without checking if the value already exists in the set.
+ ///
+ /// Returns a reference to the value just inserted.
+ ///
+ /// This operation is safe if a value does not exist in the set.
+ ///
+ /// However, if a value exists in the set already, the behavior is unspecified:
+ /// this operation may panic, loop forever, or any following operation with the set
+ /// 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 set.
+ /// For example, when constructing a set from another set, we know
+ /// that values are unique.
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn insert_unique_unchecked(&mut self, value: T) -> &T {
+ self.map.insert_unique_unchecked(value, ()).0
+ }
+
+ /// Adds a value to the set, replacing the existing value, if any, that is equal to the given
+ /// one. Returns the replaced value.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set = HashSet::new();
+ /// set.insert(Vec::<i32>::new());
+ ///
+ /// assert_eq!(set.get(&[][..]).unwrap().capacity(), 0);
+ /// set.replace(Vec::with_capacity(10));
+ /// assert_eq!(set.get(&[][..]).unwrap().capacity(), 10);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn replace(&mut self, value: T) -> Option<T> {
+ match self.map.entry(value) {
+ map::Entry::Occupied(occupied) => Some(occupied.replace_key()),
+ map::Entry::Vacant(vacant) => {
+ vacant.insert(());
+ None
+ }
+ }
+ }
+
+ /// Removes a value from the set. Returns whether the value was
+ /// present in the set.
+ ///
+ /// The value may be any borrowed form of the set's value type, but
+ /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
+ /// the value type.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set = HashSet::new();
+ ///
+ /// set.insert(2);
+ /// assert_eq!(set.remove(&2), true);
+ /// assert_eq!(set.remove(&2), false);
+ /// ```
+ ///
+ /// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
+ /// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool
+ where
+ Q: Hash + Equivalent<T>,
+ {
+ self.map.remove(value).is_some()
+ }
+
+ /// Removes and returns the value in the set, if any, that is equal to the given one.
+ ///
+ /// The value may be any borrowed form of the set's value type, but
+ /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
+ /// the value type.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set: HashSet<_> = [1, 2, 3].iter().cloned().collect();
+ /// assert_eq!(set.take(&2), Some(2));
+ /// assert_eq!(set.take(&2), None);
+ /// ```
+ ///
+ /// [`Eq`]: https://doc.rust-lang.org/std/cmp/trait.Eq.html
+ /// [`Hash`]: https://doc.rust-lang.org/std/hash/trait.Hash.html
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn take<Q: ?Sized>(&mut self, value: &Q) -> Option<T>
+ where
+ Q: Hash + Equivalent<T>,
+ {
+ // Avoid `Option::map` because it bloats LLVM IR.
+ match self.map.remove_entry(value) {
+ Some((k, _)) => Some(k),
+ None => None,
+ }
+ }
+}
+
+impl<T, S, A: Allocator> HashSet<T, S, A> {
+ /// Returns a reference to the [`RawTable`] used underneath [`HashSet`].
+ /// This function is only available if the `raw` feature of the crate is enabled.
+ ///
+ /// # Note
+ ///
+ /// Calling this function is safe, but using the raw hash table API may require
+ /// unsafe functions or blocks.
+ ///
+ /// `RawTable` API gives the lowest level of control under the set that can be useful
+ /// for extending the HashSet's API, but may lead to *[undefined behavior]*.
+ ///
+ /// [`HashSet`]: struct.HashSet.html
+ /// [`RawTable`]: crate::raw::RawTable
+ /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
+ #[cfg(feature = "raw")]
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn raw_table(&self) -> &RawTable<(T, ()), A> {
+ self.map.raw_table()
+ }
+
+ /// Returns a mutable reference to the [`RawTable`] used underneath [`HashSet`].
+ /// This function is only available if the `raw` feature of the crate is enabled.
+ ///
+ /// # Note
+ ///
+ /// Calling this function is safe, but using the raw hash table API may require
+ /// unsafe functions or blocks.
+ ///
+ /// `RawTable` API gives the lowest level of control under the set that can be useful
+ /// for extending the HashSet's API, but may lead to *[undefined behavior]*.
+ ///
+ /// [`HashSet`]: struct.HashSet.html
+ /// [`RawTable`]: crate::raw::RawTable
+ /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
+ #[cfg(feature = "raw")]
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn raw_table_mut(&mut self) -> &mut RawTable<(T, ()), A> {
+ self.map.raw_table_mut()
+ }
+}
+
+impl<T, S, A> PartialEq for HashSet<T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+ fn eq(&self, other: &Self) -> bool {
+ if self.len() != other.len() {
+ return false;
+ }
+
+ self.iter().all(|key| other.contains(key))
+ }
+}
+
+impl<T, S, A> Eq for HashSet<T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+}
+
+impl<T, S, A> fmt::Debug for HashSet<T, S, A>
+where
+ T: fmt::Debug,
+ A: Allocator,
+{
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_set().entries(self.iter()).finish()
+ }
+}
+
+impl<T, S, A> From<HashMap<T, (), S, A>> for HashSet<T, S, A>
+where
+ A: Allocator,
+{
+ fn from(map: HashMap<T, (), S, A>) -> Self {
+ Self { map }
+ }
+}
+
+impl<T, S, A> FromIterator<T> for HashSet<T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher + Default,
+ A: Default + Allocator,
+{
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self {
+ let mut set = Self::with_hasher_in(Default::default(), Default::default());
+ set.extend(iter);
+ set
+ }
+}
+
+// The default hasher is used to match the std implementation signature
+#[cfg(feature = "ahash")]
+impl<T, A, const N: usize> From<[T; N]> for HashSet<T, DefaultHashBuilder, A>
+where
+ T: Eq + Hash,
+ A: Default + Allocator,
+{
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let set1 = HashSet::from([1, 2, 3, 4]);
+ /// let set2: HashSet<_> = [1, 2, 3, 4].into();
+ /// assert_eq!(set1, set2);
+ /// ```
+ fn from(arr: [T; N]) -> Self {
+ arr.into_iter().collect()
+ }
+}
+
+impl<T, S, A> Extend<T> for HashSet<T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
+ self.map.extend(iter.into_iter().map(|k| (k, ())));
+ }
+
+ #[inline]
+ #[cfg(feature = "nightly")]
+ fn extend_one(&mut self, k: T) {
+ self.map.insert(k, ());
+ }
+
+ #[inline]
+ #[cfg(feature = "nightly")]
+ fn extend_reserve(&mut self, additional: usize) {
+ Extend::<(T, ())>::extend_reserve(&mut self.map, additional);
+ }
+}
+
+impl<'a, T, S, A> Extend<&'a T> for HashSet<T, S, A>
+where
+ T: 'a + Eq + Hash + Copy,
+ S: BuildHasher,
+ A: Allocator,
+{
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) {
+ self.extend(iter.into_iter().copied());
+ }
+
+ #[inline]
+ #[cfg(feature = "nightly")]
+ fn extend_one(&mut self, k: &'a T) {
+ self.map.insert(*k, ());
+ }
+
+ #[inline]
+ #[cfg(feature = "nightly")]
+ fn extend_reserve(&mut self, additional: usize) {
+ Extend::<(T, ())>::extend_reserve(&mut self.map, additional);
+ }
+}
+
+impl<T, S, A> Default for HashSet<T, S, A>
+where
+ S: Default,
+ A: Default + Allocator,
+{
+ /// Creates an empty `HashSet<T, S>` with the `Default` value for the hasher.
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn default() -> Self {
+ Self {
+ map: HashMap::default(),
+ }
+ }
+}
+
+impl<T, S, A> BitOr<&HashSet<T, S, A>> for &HashSet<T, S, A>
+where
+ T: Eq + Hash + Clone,
+ S: BuildHasher + Default,
+ A: Allocator,
+{
+ type Output = HashSet<T, S>;
+
+ /// Returns the union of `self` and `rhs` as a new `HashSet<T, S>`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect();
+ /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect();
+ ///
+ /// let set = &a | &b;
+ ///
+ /// let mut i = 0;
+ /// let expected = [1, 2, 3, 4, 5];
+ /// for x in &set {
+ /// assert!(expected.contains(x));
+ /// i += 1;
+ /// }
+ /// assert_eq!(i, expected.len());
+ /// ```
+ fn bitor(self, rhs: &HashSet<T, S, A>) -> HashSet<T, S> {
+ self.union(rhs).cloned().collect()
+ }
+}
+
+impl<T, S, A> BitAnd<&HashSet<T, S, A>> for &HashSet<T, S, A>
+where
+ T: Eq + Hash + Clone,
+ S: BuildHasher + Default,
+ A: Allocator,
+{
+ type Output = HashSet<T, S>;
+
+ /// Returns the intersection of `self` and `rhs` as a new `HashSet<T, S>`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect();
+ /// let b: HashSet<_> = vec![2, 3, 4].into_iter().collect();
+ ///
+ /// let set = &a & &b;
+ ///
+ /// let mut i = 0;
+ /// let expected = [2, 3];
+ /// for x in &set {
+ /// assert!(expected.contains(x));
+ /// i += 1;
+ /// }
+ /// assert_eq!(i, expected.len());
+ /// ```
+ fn bitand(self, rhs: &HashSet<T, S, A>) -> HashSet<T, S> {
+ self.intersection(rhs).cloned().collect()
+ }
+}
+
+impl<T, S> BitXor<&HashSet<T, S>> for &HashSet<T, S>
+where
+ T: Eq + Hash + Clone,
+ S: BuildHasher + Default,
+{
+ type Output = HashSet<T, S>;
+
+ /// Returns the symmetric difference of `self` and `rhs` as a new `HashSet<T, S>`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect();
+ /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect();
+ ///
+ /// let set = &a ^ &b;
+ ///
+ /// let mut i = 0;
+ /// let expected = [1, 2, 4, 5];
+ /// for x in &set {
+ /// assert!(expected.contains(x));
+ /// i += 1;
+ /// }
+ /// assert_eq!(i, expected.len());
+ /// ```
+ fn bitxor(self, rhs: &HashSet<T, S>) -> HashSet<T, S> {
+ self.symmetric_difference(rhs).cloned().collect()
+ }
+}
+
+impl<T, S> Sub<&HashSet<T, S>> for &HashSet<T, S>
+where
+ T: Eq + Hash + Clone,
+ S: BuildHasher + Default,
+{
+ type Output = HashSet<T, S>;
+
+ /// Returns the difference of `self` and `rhs` as a new `HashSet<T, S>`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect();
+ /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect();
+ ///
+ /// let set = &a - &b;
+ ///
+ /// let mut i = 0;
+ /// let expected = [1, 2];
+ /// for x in &set {
+ /// assert!(expected.contains(x));
+ /// i += 1;
+ /// }
+ /// assert_eq!(i, expected.len());
+ /// ```
+ fn sub(self, rhs: &HashSet<T, S>) -> HashSet<T, S> {
+ self.difference(rhs).cloned().collect()
+ }
+}
+
+/// An iterator over the items of a `HashSet`.
+///
+/// This `struct` is created by the [`iter`] method on [`HashSet`].
+/// See its documentation for more.
+///
+/// [`HashSet`]: struct.HashSet.html
+/// [`iter`]: struct.HashSet.html#method.iter
+pub struct Iter<'a, K> {
+ iter: Keys<'a, K, ()>,
+}
+
+/// An owning iterator over the items of a `HashSet`.
+///
+/// This `struct` is created by the [`into_iter`] method on [`HashSet`]
+/// (provided by the `IntoIterator` trait). See its documentation for more.
+///
+/// [`HashSet`]: struct.HashSet.html
+/// [`into_iter`]: struct.HashSet.html#method.into_iter
+pub struct IntoIter<K, A: Allocator = Global> {
+ iter: map::IntoIter<K, (), A>,
+}
+
+/// A draining iterator over the items of a `HashSet`.
+///
+/// This `struct` is created by the [`drain`] method on [`HashSet`].
+/// See its documentation for more.
+///
+/// [`HashSet`]: struct.HashSet.html
+/// [`drain`]: struct.HashSet.html#method.drain
+pub struct Drain<'a, K, A: Allocator = Global> {
+ iter: map::Drain<'a, K, (), A>,
+}
+
+/// A draining iterator over entries of a `HashSet` which don't satisfy the predicate `f`.
+///
+/// This `struct` is created by the [`extract_if`] method on [`HashSet`]. See its
+/// documentation for more.
+///
+/// [`extract_if`]: struct.HashSet.html#method.extract_if
+/// [`HashSet`]: struct.HashSet.html
+#[must_use = "Iterators are lazy unless consumed"]
+pub struct ExtractIf<'a, K, F, A: Allocator = Global>
+where
+ F: FnMut(&K) -> bool,
+{
+ f: F,
+ inner: ExtractIfInner<'a, K, (), A>,
+}
+
+/// A lazy iterator producing elements in the intersection of `HashSet`s.
+///
+/// This `struct` is created by the [`intersection`] method on [`HashSet`].
+/// See its documentation for more.
+///
+/// [`HashSet`]: struct.HashSet.html
+/// [`intersection`]: struct.HashSet.html#method.intersection
+pub struct Intersection<'a, T, S, A: Allocator = Global> {
+ // iterator of the first set
+ iter: Iter<'a, T>,
+ // the second set
+ other: &'a HashSet<T, S, A>,
+}
+
+/// A lazy iterator producing elements in the difference of `HashSet`s.
+///
+/// This `struct` is created by the [`difference`] method on [`HashSet`].
+/// See its documentation for more.
+///
+/// [`HashSet`]: struct.HashSet.html
+/// [`difference`]: struct.HashSet.html#method.difference
+pub struct Difference<'a, T, S, A: Allocator = Global> {
+ // iterator of the first set
+ iter: Iter<'a, T>,
+ // the second set
+ other: &'a HashSet<T, S, A>,
+}
+
+/// A lazy iterator producing elements in the symmetric difference of `HashSet`s.
+///
+/// This `struct` is created by the [`symmetric_difference`] method on
+/// [`HashSet`]. See its documentation for more.
+///
+/// [`HashSet`]: struct.HashSet.html
+/// [`symmetric_difference`]: struct.HashSet.html#method.symmetric_difference
+pub struct SymmetricDifference<'a, T, S, A: Allocator = Global> {
+ iter: Chain<Difference<'a, T, S, A>, Difference<'a, T, S, A>>,
+}
+
+/// A lazy iterator producing elements in the union of `HashSet`s.
+///
+/// This `struct` is created by the [`union`] method on [`HashSet`].
+/// See its documentation for more.
+///
+/// [`HashSet`]: struct.HashSet.html
+/// [`union`]: struct.HashSet.html#method.union
+pub struct Union<'a, T, S, A: Allocator = Global> {
+ iter: Chain<Iter<'a, T>, Difference<'a, T, S, A>>,
+}
+
+impl<'a, T, S, A: Allocator> IntoIterator for &'a HashSet<T, S, A> {
+ type Item = &'a T;
+ type IntoIter = Iter<'a, T>;
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn into_iter(self) -> Iter<'a, T> {
+ self.iter()
+ }
+}
+
+impl<T, S, A: Allocator> IntoIterator for HashSet<T, S, A> {
+ type Item = T;
+ type IntoIter = IntoIter<T, A>;
+
+ /// Creates a consuming iterator, that is, one that moves each value out
+ /// of the set in arbitrary order. The set cannot be used after calling
+ /// this.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ /// let mut set = HashSet::new();
+ /// set.insert("a".to_string());
+ /// set.insert("b".to_string());
+ ///
+ /// // Not possible to collect to a Vec<String> with a regular `.iter()`.
+ /// let v: Vec<String> = set.into_iter().collect();
+ ///
+ /// // Will print in an arbitrary order.
+ /// for x in &v {
+ /// println!("{}", x);
+ /// }
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn into_iter(self) -> IntoIter<T, A> {
+ IntoIter {
+ iter: self.map.into_iter(),
+ }
+ }
+}
+
+impl<K> Clone for Iter<'_, K> {
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn clone(&self) -> Self {
+ Iter {
+ iter: self.iter.clone(),
+ }
+ }
+}
+impl<'a, K> Iterator for Iter<'a, K> {
+ type Item = &'a K;
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn next(&mut self) -> Option<&'a K> {
+ self.iter.next()
+ }
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iter.size_hint()
+ }
+}
+impl<'a, K> ExactSizeIterator for Iter<'a, K> {
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn len(&self) -> usize {
+ self.iter.len()
+ }
+}
+impl<K> FusedIterator for Iter<'_, K> {}
+
+impl<K: fmt::Debug> fmt::Debug for Iter<'_, K> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_list().entries(self.clone()).finish()
+ }
+}
+
+impl<K, A: Allocator> Iterator for IntoIter<K, A> {
+ type Item = K;
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn next(&mut self) -> Option<K> {
+ // Avoid `Option::map` because it bloats LLVM IR.
+ match self.iter.next() {
+ Some((k, _)) => Some(k),
+ None => None,
+ }
+ }
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iter.size_hint()
+ }
+}
+impl<K, A: Allocator> ExactSizeIterator for IntoIter<K, A> {
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn len(&self) -> usize {
+ self.iter.len()
+ }
+}
+impl<K, A: Allocator> FusedIterator for IntoIter<K, A> {}
+
+impl<K: fmt::Debug, A: Allocator> fmt::Debug for IntoIter<K, A> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ let entries_iter = self.iter.iter().map(|(k, _)| k);
+ f.debug_list().entries(entries_iter).finish()
+ }
+}
+
+impl<K, A: Allocator> Iterator for Drain<'_, K, A> {
+ type Item = K;
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn next(&mut self) -> Option<K> {
+ // Avoid `Option::map` because it bloats LLVM IR.
+ match self.iter.next() {
+ Some((k, _)) => Some(k),
+ None => None,
+ }
+ }
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iter.size_hint()
+ }
+}
+impl<K, A: Allocator> ExactSizeIterator for Drain<'_, K, A> {
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn len(&self) -> usize {
+ self.iter.len()
+ }
+}
+impl<K, A: Allocator> FusedIterator for Drain<'_, K, A> {}
+
+impl<K: fmt::Debug, A: Allocator> fmt::Debug for Drain<'_, K, A> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ let entries_iter = self.iter.iter().map(|(k, _)| k);
+ f.debug_list().entries(entries_iter).finish()
+ }
+}
+
+impl<K, F, A: Allocator> Iterator for ExtractIf<'_, K, F, A>
+where
+ F: FnMut(&K) -> bool,
+{
+ type Item = K;
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn next(&mut self) -> Option<Self::Item> {
+ let f = &mut self.f;
+ let (k, _) = self.inner.next(&mut |k, _| f(k))?;
+ Some(k)
+ }
+
+ #[inline]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (0, self.inner.iter.size_hint().1)
+ }
+}
+
+impl<K, F, A: Allocator> FusedIterator for ExtractIf<'_, K, F, A> where F: FnMut(&K) -> bool {}
+
+impl<T, S, A: Allocator> Clone for Intersection<'_, T, S, A> {
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn clone(&self) -> Self {
+ Intersection {
+ iter: self.iter.clone(),
+ ..*self
+ }
+ }
+}
+
+impl<'a, T, S, A> Iterator for Intersection<'a, T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+ type Item = &'a T;
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn next(&mut self) -> Option<&'a T> {
+ loop {
+ let elt = self.iter.next()?;
+ if self.other.contains(elt) {
+ return Some(elt);
+ }
+ }
+ }
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ let (_, upper) = self.iter.size_hint();
+ (0, upper)
+ }
+}
+
+impl<T, S, A> fmt::Debug for Intersection<'_, T, S, A>
+where
+ T: fmt::Debug + Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_list().entries(self.clone()).finish()
+ }
+}
+
+impl<T, S, A> FusedIterator for Intersection<'_, T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+}
+
+impl<T, S, A: Allocator> Clone for Difference<'_, T, S, A> {
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn clone(&self) -> Self {
+ Difference {
+ iter: self.iter.clone(),
+ ..*self
+ }
+ }
+}
+
+impl<'a, T, S, A> Iterator for Difference<'a, T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+ type Item = &'a T;
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn next(&mut self) -> Option<&'a T> {
+ loop {
+ let elt = self.iter.next()?;
+ if !self.other.contains(elt) {
+ return Some(elt);
+ }
+ }
+ }
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ let (_, upper) = self.iter.size_hint();
+ (0, upper)
+ }
+}
+
+impl<T, S, A> FusedIterator for Difference<'_, T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+}
+
+impl<T, S, A> fmt::Debug for Difference<'_, T, S, A>
+where
+ T: fmt::Debug + Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_list().entries(self.clone()).finish()
+ }
+}
+
+impl<T, S, A: Allocator> Clone for SymmetricDifference<'_, T, S, A> {
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn clone(&self) -> Self {
+ SymmetricDifference {
+ iter: self.iter.clone(),
+ }
+ }
+}
+
+impl<'a, T, S, A> Iterator for SymmetricDifference<'a, T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+ type Item = &'a T;
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn next(&mut self) -> Option<&'a T> {
+ self.iter.next()
+ }
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iter.size_hint()
+ }
+}
+
+impl<T, S, A> FusedIterator for SymmetricDifference<'_, T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+}
+
+impl<T, S, A> fmt::Debug for SymmetricDifference<'_, T, S, A>
+where
+ T: fmt::Debug + Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_list().entries(self.clone()).finish()
+ }
+}
+
+impl<T, S, A: Allocator> Clone for Union<'_, T, S, A> {
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn clone(&self) -> Self {
+ Union {
+ iter: self.iter.clone(),
+ }
+ }
+}
+
+impl<T, S, A> FusedIterator for Union<'_, T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+}
+
+impl<T, S, A> fmt::Debug for Union<'_, T, S, A>
+where
+ T: fmt::Debug + Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_list().entries(self.clone()).finish()
+ }
+}
+
+impl<'a, T, S, A> Iterator for Union<'a, T, S, A>
+where
+ T: Eq + Hash,
+ S: BuildHasher,
+ A: Allocator,
+{
+ type Item = &'a T;
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn next(&mut self) -> Option<&'a T> {
+ self.iter.next()
+ }
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iter.size_hint()
+ }
+}
+
+/// A view into a single entry in a set, which may either be vacant or occupied.
+///
+/// This `enum` is constructed from the [`entry`] method on [`HashSet`].
+///
+/// [`HashSet`]: struct.HashSet.html
+/// [`entry`]: struct.HashSet.html#method.entry
+///
+/// # Examples
+///
+/// ```
+/// use hashbrown::hash_set::{Entry, HashSet, OccupiedEntry};
+///
+/// let mut set = HashSet::new();
+/// set.extend(["a", "b", "c"]);
+/// assert_eq!(set.len(), 3);
+///
+/// // Existing value (insert)
+/// let entry: Entry<_, _> = set.entry("a");
+/// let _raw_o: OccupiedEntry<_, _> = entry.insert();
+/// assert_eq!(set.len(), 3);
+/// // Nonexistent value (insert)
+/// set.entry("d").insert();
+///
+/// // Existing value (or_insert)
+/// set.entry("b").or_insert();
+/// // Nonexistent value (or_insert)
+/// set.entry("e").or_insert();
+///
+/// println!("Our HashSet: {:?}", set);
+///
+/// let mut vec: Vec<_> = set.iter().copied().collect();
+/// // 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", "b", "c", "d", "e"]);
+/// ```
+pub enum Entry<'a, T, S, A = Global>
+where
+ A: Allocator,
+{
+ /// An occupied entry.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::hash_set::{Entry, HashSet};
+ /// let mut set: HashSet<_> = ["a", "b"].into();
+ ///
+ /// match set.entry("a") {
+ /// Entry::Vacant(_) => unreachable!(),
+ /// Entry::Occupied(_) => { }
+ /// }
+ /// ```
+ Occupied(OccupiedEntry<'a, T, S, A>),
+
+ /// A vacant entry.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::hash_set::{Entry, HashSet};
+ /// let mut set: HashSet<&str> = HashSet::new();
+ ///
+ /// match set.entry("a") {
+ /// Entry::Occupied(_) => unreachable!(),
+ /// Entry::Vacant(_) => { }
+ /// }
+ /// ```
+ Vacant(VacantEntry<'a, T, S, A>),
+}
+
+impl<T: fmt::Debug, S, A: Allocator> fmt::Debug for Entry<'_, T, S, A> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match *self {
+ Entry::Vacant(ref v) => f.debug_tuple("Entry").field(v).finish(),
+ Entry::Occupied(ref o) => f.debug_tuple("Entry").field(o).finish(),
+ }
+ }
+}
+
+/// A view into an occupied entry in a `HashSet`.
+/// It is part of the [`Entry`] enum.
+///
+/// [`Entry`]: enum.Entry.html
+///
+/// # Examples
+///
+/// ```
+/// use hashbrown::hash_set::{Entry, HashSet, OccupiedEntry};
+///
+/// let mut set = HashSet::new();
+/// set.extend(["a", "b", "c"]);
+///
+/// let _entry_o: OccupiedEntry<_, _> = set.entry("a").insert();
+/// assert_eq!(set.len(), 3);
+///
+/// // Existing key
+/// match set.entry("a") {
+/// Entry::Vacant(_) => unreachable!(),
+/// Entry::Occupied(view) => {
+/// assert_eq!(view.get(), &"a");
+/// }
+/// }
+///
+/// assert_eq!(set.len(), 3);
+///
+/// // Existing key (take)
+/// match set.entry("c") {
+/// Entry::Vacant(_) => unreachable!(),
+/// Entry::Occupied(view) => {
+/// assert_eq!(view.remove(), "c");
+/// }
+/// }
+/// assert_eq!(set.get(&"c"), None);
+/// assert_eq!(set.len(), 2);
+/// ```
+pub struct OccupiedEntry<'a, T, S, A: Allocator = Global> {
+ inner: map::OccupiedEntry<'a, T, (), S, A>,
+}
+
+impl<T: fmt::Debug, S, A: Allocator> fmt::Debug for OccupiedEntry<'_, T, S, A> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_struct("OccupiedEntry")
+ .field("value", self.get())
+ .finish()
+ }
+}
+
+/// A view into a vacant entry in a `HashSet`.
+/// It is part of the [`Entry`] enum.
+///
+/// [`Entry`]: enum.Entry.html
+///
+/// # Examples
+///
+/// ```
+/// use hashbrown::hash_set::{Entry, HashSet, VacantEntry};
+///
+/// let mut set = HashSet::<&str>::new();
+///
+/// let entry_v: VacantEntry<_, _> = match set.entry("a") {
+/// Entry::Vacant(view) => view,
+/// Entry::Occupied(_) => unreachable!(),
+/// };
+/// entry_v.insert();
+/// assert!(set.contains("a") && set.len() == 1);
+///
+/// // Nonexistent key (insert)
+/// match set.entry("b") {
+/// Entry::Vacant(view) => view.insert(),
+/// Entry::Occupied(_) => unreachable!(),
+/// }
+/// assert!(set.contains("b") && set.len() == 2);
+/// ```
+pub struct VacantEntry<'a, T, S, A: Allocator = Global> {
+ inner: map::VacantEntry<'a, T, (), S, A>,
+}
+
+impl<T: fmt::Debug, S, A: Allocator> fmt::Debug for VacantEntry<'_, T, S, A> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_tuple("VacantEntry").field(self.get()).finish()
+ }
+}
+
+impl<'a, T, S, A: Allocator> Entry<'a, T, S, A> {
+ /// Sets the value of the entry, and returns an OccupiedEntry.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set: HashSet<&str> = HashSet::new();
+ /// let entry = set.entry("horseyland").insert();
+ ///
+ /// assert_eq!(entry.get(), &"horseyland");
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn insert(self) -> OccupiedEntry<'a, T, S, A>
+ where
+ T: Hash,
+ S: BuildHasher,
+ {
+ match self {
+ Entry::Occupied(entry) => entry,
+ Entry::Vacant(entry) => entry.insert_entry(),
+ }
+ }
+
+ /// Ensures a value is in the entry by inserting if it was vacant.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set: HashSet<&str> = HashSet::new();
+ ///
+ /// // nonexistent key
+ /// set.entry("poneyland").or_insert();
+ /// assert!(set.contains("poneyland"));
+ ///
+ /// // existing key
+ /// set.entry("poneyland").or_insert();
+ /// assert!(set.contains("poneyland"));
+ /// assert_eq!(set.len(), 1);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn or_insert(self)
+ where
+ T: Hash,
+ S: BuildHasher,
+ {
+ if let Entry::Vacant(entry) = self {
+ entry.insert();
+ }
+ }
+
+ /// Returns a reference to this entry's value.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set: HashSet<&str> = HashSet::new();
+ /// set.entry("poneyland").or_insert();
+ /// // existing key
+ /// assert_eq!(set.entry("poneyland").get(), &"poneyland");
+ /// // nonexistent key
+ /// assert_eq!(set.entry("horseland").get(), &"horseland");
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn get(&self) -> &T {
+ match *self {
+ Entry::Occupied(ref entry) => entry.get(),
+ Entry::Vacant(ref entry) => entry.get(),
+ }
+ }
+}
+
+impl<T, S, A: Allocator> OccupiedEntry<'_, T, S, A> {
+ /// Gets a reference to the value in the entry.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::hash_set::{Entry, HashSet};
+ ///
+ /// let mut set: HashSet<&str> = HashSet::new();
+ /// set.entry("poneyland").or_insert();
+ ///
+ /// match set.entry("poneyland") {
+ /// Entry::Vacant(_) => panic!(),
+ /// Entry::Occupied(entry) => assert_eq!(entry.get(), &"poneyland"),
+ /// }
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn get(&self) -> &T {
+ self.inner.key()
+ }
+
+ /// Takes the value out of the entry, and returns it.
+ /// Keeps the allocated memory for reuse.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ /// use hashbrown::hash_set::Entry;
+ ///
+ /// let mut set: HashSet<&str> = HashSet::new();
+ /// // The set is empty
+ /// assert!(set.is_empty() && set.capacity() == 0);
+ ///
+ /// set.entry("poneyland").or_insert();
+ /// let capacity_before_remove = set.capacity();
+ ///
+ /// if let Entry::Occupied(o) = set.entry("poneyland") {
+ /// assert_eq!(o.remove(), "poneyland");
+ /// }
+ ///
+ /// assert_eq!(set.contains("poneyland"), false);
+ /// // Now set hold none elements but capacity is equal to the old one
+ /// assert!(set.len() == 0 && set.capacity() == capacity_before_remove);
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn remove(self) -> T {
+ self.inner.remove_entry().0
+ }
+
+ /// Replaces the entry, returning the old value. The new value in the hash map will be
+ /// the value used to create this entry.
+ ///
+ /// # Panics
+ ///
+ /// Will panic if this OccupiedEntry was created through [`Entry::insert`].
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::hash_set::{Entry, HashSet};
+ /// use std::rc::Rc;
+ ///
+ /// let mut set: HashSet<Rc<String>> = HashSet::new();
+ /// let key_one = Rc::new("Stringthing".to_string());
+ /// let key_two = Rc::new("Stringthing".to_string());
+ ///
+ /// set.insert(key_one.clone());
+ /// assert!(Rc::strong_count(&key_one) == 2 && Rc::strong_count(&key_two) == 1);
+ ///
+ /// match set.entry(key_two.clone()) {
+ /// Entry::Occupied(entry) => {
+ /// let old_key: Rc<String> = entry.replace();
+ /// assert!(Rc::ptr_eq(&key_one, &old_key));
+ /// }
+ /// Entry::Vacant(_) => panic!(),
+ /// }
+ ///
+ /// assert!(Rc::strong_count(&key_one) == 1 && Rc::strong_count(&key_two) == 2);
+ /// assert!(set.contains(&"Stringthing".to_owned()));
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn replace(self) -> T {
+ self.inner.replace_key()
+ }
+}
+
+impl<'a, T, S, A: Allocator> VacantEntry<'a, T, S, A> {
+ /// Gets a reference to the value that would be used when inserting
+ /// through the `VacantEntry`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ ///
+ /// let mut set: HashSet<&str> = HashSet::new();
+ /// assert_eq!(set.entry("poneyland").get(), &"poneyland");
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn get(&self) -> &T {
+ self.inner.key()
+ }
+
+ /// Take ownership of the value.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::hash_set::{Entry, HashSet};
+ ///
+ /// let mut set: HashSet<&str> = HashSet::new();
+ ///
+ /// match set.entry("poneyland") {
+ /// Entry::Occupied(_) => panic!(),
+ /// Entry::Vacant(v) => assert_eq!(v.into_value(), "poneyland"),
+ /// }
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn into_value(self) -> T {
+ self.inner.into_key()
+ }
+
+ /// Sets the value of the entry with the VacantEntry's value.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use hashbrown::HashSet;
+ /// use hashbrown::hash_set::Entry;
+ ///
+ /// let mut set: HashSet<&str> = HashSet::new();
+ ///
+ /// if let Entry::Vacant(o) = set.entry("poneyland") {
+ /// o.insert();
+ /// }
+ /// assert!(set.contains("poneyland"));
+ /// ```
+ #[cfg_attr(feature = "inline-more", inline)]
+ pub fn insert(self)
+ where
+ T: Hash,
+ S: BuildHasher,
+ {
+ self.inner.insert(());
+ }
+
+ #[cfg_attr(feature = "inline-more", inline)]
+ fn insert_entry(self) -> OccupiedEntry<'a, T, S, A>
+ where
+ T: Hash,
+ S: BuildHasher,
+ {
+ OccupiedEntry {
+ inner: self.inner.insert_entry(()),
+ }
+ }
+}
+
+#[allow(dead_code)]
+fn assert_covariance() {
+ fn set<'new>(v: HashSet<&'static str>) -> HashSet<&'new str> {
+ v
+ }
+ fn iter<'a, 'new>(v: Iter<'a, &'static str>) -> Iter<'a, &'new str> {
+ v
+ }
+ fn into_iter<'new, A: Allocator>(v: IntoIter<&'static str, A>) -> IntoIter<&'new str, A> {
+ v
+ }
+ fn difference<'a, 'new, A: Allocator>(
+ v: Difference<'a, &'static str, DefaultHashBuilder, A>,
+ ) -> Difference<'a, &'new str, DefaultHashBuilder, A> {
+ v
+ }
+ fn symmetric_difference<'a, 'new, A: Allocator>(
+ v: SymmetricDifference<'a, &'static str, DefaultHashBuilder, A>,
+ ) -> SymmetricDifference<'a, &'new str, DefaultHashBuilder, A> {
+ v
+ }
+ fn intersection<'a, 'new, A: Allocator>(
+ v: Intersection<'a, &'static str, DefaultHashBuilder, A>,
+ ) -> Intersection<'a, &'new str, DefaultHashBuilder, A> {
+ v
+ }
+ fn union<'a, 'new, A: Allocator>(
+ v: Union<'a, &'static str, DefaultHashBuilder, A>,
+ ) -> Union<'a, &'new str, DefaultHashBuilder, A> {
+ v
+ }
+ fn drain<'new, A: Allocator>(d: Drain<'static, &'static str, A>) -> Drain<'new, &'new str, A> {
+ d
+ }
+}
+
+#[cfg(test)]
+mod test_set {
+ use super::super::map::DefaultHashBuilder;
+ use super::HashSet;
+ use std::vec::Vec;
+
+ #[test]
+ fn test_zero_capacities() {
+ type HS = HashSet<i32>;
+
+ let s = HS::new();
+ assert_eq!(s.capacity(), 0);
+
+ let s = HS::default();
+ assert_eq!(s.capacity(), 0);
+
+ let s = HS::with_hasher(DefaultHashBuilder::default());
+ assert_eq!(s.capacity(), 0);
+
+ let s = HS::with_capacity(0);
+ assert_eq!(s.capacity(), 0);
+
+ let s = HS::with_capacity_and_hasher(0, DefaultHashBuilder::default());
+ assert_eq!(s.capacity(), 0);
+
+ let mut s = HS::new();
+ s.insert(1);
+ s.insert(2);
+ s.remove(&1);
+ s.remove(&2);
+ s.shrink_to_fit();
+ assert_eq!(s.capacity(), 0);
+
+ let mut s = HS::new();
+ s.reserve(0);
+ assert_eq!(s.capacity(), 0);
+ }
+
+ #[test]
+ fn test_disjoint() {
+ let mut xs = HashSet::new();
+ let mut ys = HashSet::new();
+ assert!(xs.is_disjoint(&ys));
+ assert!(ys.is_disjoint(&xs));
+ assert!(xs.insert(5));
+ assert!(ys.insert(11));
+ assert!(xs.is_disjoint(&ys));
+ assert!(ys.is_disjoint(&xs));
+ assert!(xs.insert(7));
+ assert!(xs.insert(19));
+ assert!(xs.insert(4));
+ assert!(ys.insert(2));
+ assert!(ys.insert(-11));
+ assert!(xs.is_disjoint(&ys));
+ assert!(ys.is_disjoint(&xs));
+ assert!(ys.insert(7));
+ assert!(!xs.is_disjoint(&ys));
+ assert!(!ys.is_disjoint(&xs));
+ }
+
+ #[test]
+ fn test_subset_and_superset() {
+ let mut a = HashSet::new();
+ assert!(a.insert(0));
+ assert!(a.insert(5));
+ assert!(a.insert(11));
+ assert!(a.insert(7));
+
+ let mut b = HashSet::new();
+ assert!(b.insert(0));
+ assert!(b.insert(7));
+ assert!(b.insert(19));
+ assert!(b.insert(250));
+ assert!(b.insert(11));
+ assert!(b.insert(200));
+
+ assert!(!a.is_subset(&b));
+ assert!(!a.is_superset(&b));
+ assert!(!b.is_subset(&a));
+ assert!(!b.is_superset(&a));
+
+ assert!(b.insert(5));
+
+ assert!(a.is_subset(&b));
+ assert!(!a.is_superset(&b));
+ assert!(!b.is_subset(&a));
+ assert!(b.is_superset(&a));
+ }
+
+ #[test]
+ fn test_iterate() {
+ let mut a = HashSet::new();
+ for i in 0..32 {
+ assert!(a.insert(i));
+ }
+ let mut observed: u32 = 0;
+ for k in &a {
+ observed |= 1 << *k;
+ }
+ assert_eq!(observed, 0xFFFF_FFFF);
+ }
+
+ #[test]
+ fn test_intersection() {
+ let mut a = HashSet::new();
+ let mut b = HashSet::new();
+
+ assert!(a.insert(11));
+ assert!(a.insert(1));
+ assert!(a.insert(3));
+ assert!(a.insert(77));
+ assert!(a.insert(103));
+ assert!(a.insert(5));
+ assert!(a.insert(-5));
+
+ assert!(b.insert(2));
+ assert!(b.insert(11));
+ assert!(b.insert(77));
+ assert!(b.insert(-9));
+ assert!(b.insert(-42));
+ assert!(b.insert(5));
+ assert!(b.insert(3));
+
+ let mut i = 0;
+ let expected = [3, 5, 11, 77];
+ for x in a.intersection(&b) {
+ assert!(expected.contains(x));
+ i += 1;
+ }
+ assert_eq!(i, expected.len());
+ }
+
+ #[test]
+ fn test_difference() {
+ let mut a = HashSet::new();
+ let mut b = HashSet::new();
+
+ assert!(a.insert(1));
+ assert!(a.insert(3));
+ assert!(a.insert(5));
+ assert!(a.insert(9));
+ assert!(a.insert(11));
+
+ assert!(b.insert(3));
+ assert!(b.insert(9));
+
+ let mut i = 0;
+ let expected = [1, 5, 11];
+ for x in a.difference(&b) {
+ assert!(expected.contains(x));
+ i += 1;
+ }
+ assert_eq!(i, expected.len());
+ }
+
+ #[test]
+ fn test_symmetric_difference() {
+ let mut a = HashSet::new();
+ let mut b = HashSet::new();
+
+ assert!(a.insert(1));
+ assert!(a.insert(3));
+ assert!(a.insert(5));
+ assert!(a.insert(9));
+ assert!(a.insert(11));
+
+ assert!(b.insert(-2));
+ assert!(b.insert(3));
+ assert!(b.insert(9));
+ assert!(b.insert(14));
+ assert!(b.insert(22));
+
+ let mut i = 0;
+ let expected = [-2, 1, 5, 11, 14, 22];
+ for x in a.symmetric_difference(&b) {
+ assert!(expected.contains(x));
+ i += 1;
+ }
+ assert_eq!(i, expected.len());
+ }
+
+ #[test]
+ fn test_union() {
+ let mut a = HashSet::new();
+ let mut b = HashSet::new();
+
+ assert!(a.insert(1));
+ assert!(a.insert(3));
+ assert!(a.insert(5));
+ assert!(a.insert(9));
+ assert!(a.insert(11));
+ assert!(a.insert(16));
+ assert!(a.insert(19));
+ assert!(a.insert(24));
+
+ assert!(b.insert(-2));
+ assert!(b.insert(1));
+ assert!(b.insert(5));
+ assert!(b.insert(9));
+ assert!(b.insert(13));
+ assert!(b.insert(19));
+
+ let mut i = 0;
+ let expected = [-2, 1, 3, 5, 9, 11, 13, 16, 19, 24];
+ for x in a.union(&b) {
+ assert!(expected.contains(x));
+ i += 1;
+ }
+ assert_eq!(i, expected.len());
+ }
+
+ #[test]
+ fn test_from_map() {
+ let mut a = crate::HashMap::new();
+ a.insert(1, ());
+ a.insert(2, ());
+ a.insert(3, ());
+ a.insert(4, ());
+
+ let a: HashSet<_> = a.into();
+
+ assert_eq!(a.len(), 4);
+ assert!(a.contains(&1));
+ assert!(a.contains(&2));
+ assert!(a.contains(&3));
+ assert!(a.contains(&4));
+ }
+
+ #[test]
+ fn test_from_iter() {
+ let xs = [1, 2, 2, 3, 4, 5, 6, 7, 8, 9];
+
+ let set: HashSet<_> = xs.iter().copied().collect();
+
+ for x in &xs {
+ assert!(set.contains(x));
+ }
+
+ assert_eq!(set.iter().len(), xs.len() - 1);
+ }
+
+ #[test]
+ fn test_move_iter() {
+ let hs = {
+ let mut hs = HashSet::new();
+
+ hs.insert('a');
+ hs.insert('b');
+
+ hs
+ };
+
+ let v = hs.into_iter().collect::<Vec<char>>();
+ assert!(v == ['a', 'b'] || v == ['b', 'a']);
+ }
+
+ #[test]
+ fn test_eq() {
+ // These constants once happened to expose a bug in insert().
+ // I'm keeping them around to prevent a regression.
+ let mut s1 = HashSet::new();
+
+ s1.insert(1);
+ s1.insert(2);
+ s1.insert(3);
+
+ let mut s2 = HashSet::new();
+
+ s2.insert(1);
+ s2.insert(2);
+
+ assert!(s1 != s2);
+
+ s2.insert(3);
+
+ assert_eq!(s1, s2);
+ }
+
+ #[test]
+ fn test_show() {
+ let mut set = HashSet::new();
+ let empty = HashSet::<i32>::new();
+
+ set.insert(1);
+ set.insert(2);
+
+ let set_str = format!("{set:?}");
+
+ assert!(set_str == "{1, 2}" || set_str == "{2, 1}");
+ assert_eq!(format!("{empty:?}"), "{}");
+ }
+
+ #[test]
+ fn test_trivial_drain() {
+ let mut s = HashSet::<i32>::new();
+ for _ in s.drain() {}
+ assert!(s.is_empty());
+ drop(s);
+
+ let mut s = HashSet::<i32>::new();
+ drop(s.drain());
+ assert!(s.is_empty());
+ }
+
+ #[test]
+ fn test_drain() {
+ let mut s: HashSet<_> = (1..100).collect();
+
+ // try this a bunch of times to make sure we don't screw up internal state.
+ for _ in 0..20 {
+ assert_eq!(s.len(), 99);
+
+ {
+ let mut last_i = 0;
+ let mut d = s.drain();
+ for (i, x) in d.by_ref().take(50).enumerate() {
+ last_i = i;
+ assert!(x != 0);
+ }
+ assert_eq!(last_i, 49);
+ }
+
+ for _ in &s {
+ panic!("s should be empty!");
+ }
+
+ // reset to try again.
+ s.extend(1..100);
+ }
+ }
+
+ #[test]
+ fn test_replace() {
+ use core::hash;
+
+ #[derive(Debug)]
+ struct Foo(&'static str, i32);
+
+ impl PartialEq for Foo {
+ fn eq(&self, other: &Self) -> bool {
+ self.0 == other.0
+ }
+ }
+
+ impl Eq for Foo {}
+
+ impl hash::Hash for Foo {
+ fn hash<H: hash::Hasher>(&self, h: &mut H) {
+ self.0.hash(h);
+ }
+ }
+
+ let mut s = HashSet::new();
+ assert_eq!(s.replace(Foo("a", 1)), None);
+ assert_eq!(s.len(), 1);
+ assert_eq!(s.replace(Foo("a", 2)), Some(Foo("a", 1)));
+ assert_eq!(s.len(), 1);
+
+ let mut it = s.iter();
+ assert_eq!(it.next(), Some(&Foo("a", 2)));
+ assert_eq!(it.next(), None);
+ }
+
+ #[test]
+ #[allow(clippy::needless_borrow)]
+ fn test_extend_ref() {
+ let mut a = HashSet::new();
+ a.insert(1);
+
+ a.extend([2, 3, 4]);
+
+ assert_eq!(a.len(), 4);
+ assert!(a.contains(&1));
+ assert!(a.contains(&2));
+ assert!(a.contains(&3));
+ assert!(a.contains(&4));
+
+ let mut b = HashSet::new();
+ b.insert(5);
+ b.insert(6);
+
+ a.extend(&b);
+
+ assert_eq!(a.len(), 6);
+ assert!(a.contains(&1));
+ assert!(a.contains(&2));
+ assert!(a.contains(&3));
+ assert!(a.contains(&4));
+ assert!(a.contains(&5));
+ assert!(a.contains(&6));
+ }
+
+ #[test]
+ fn test_retain() {
+ let xs = [1, 2, 3, 4, 5, 6];
+ let mut set: HashSet<i32> = xs.iter().copied().collect();
+ set.retain(|&k| k % 2 == 0);
+ assert_eq!(set.len(), 3);
+ assert!(set.contains(&2));
+ assert!(set.contains(&4));
+ assert!(set.contains(&6));
+ }
+
+ #[test]
+ fn test_extract_if() {
+ {
+ let mut set: HashSet<i32> = (0..8).collect();
+ let drained = set.extract_if(|&k| k % 2 == 0);
+ let mut out = drained.collect::<Vec<_>>();
+ out.sort_unstable();
+ assert_eq!(vec![0, 2, 4, 6], out);
+ assert_eq!(set.len(), 4);
+ }
+ {
+ let mut set: HashSet<i32> = (0..8).collect();
+ set.extract_if(|&k| k % 2 == 0).for_each(drop);
+ assert_eq!(set.len(), 4, "Removes non-matching items on drop");
+ }
+ }
+
+ #[test]
+ fn test_const_with_hasher() {
+ use core::hash::BuildHasher;
+ use std::collections::hash_map::DefaultHasher;
+
+ #[derive(Clone)]
+ struct MyHasher;
+ impl BuildHasher for MyHasher {
+ type Hasher = DefaultHasher;
+
+ fn build_hasher(&self) -> DefaultHasher {
+ DefaultHasher::new()
+ }
+ }
+
+ const EMPTY_SET: HashSet<u32, MyHasher> = HashSet::with_hasher(MyHasher);
+
+ let mut set = EMPTY_SET;
+ set.insert(19);
+ assert!(set.contains(&19));
+ }
+
+ #[test]
+ fn rehash_in_place() {
+ let mut set = HashSet::new();
+
+ for i in 0..224 {
+ set.insert(i);
+ }
+
+ assert_eq!(
+ set.capacity(),
+ 224,
+ "The set must be at or close to capacity to trigger a re hashing"
+ );
+
+ for i in 100..1400 {
+ set.remove(&(i - 100));
+ set.insert(i);
+ }
+ }
+
+ #[test]
+ fn collect() {
+ // At the time of writing, this hits the ZST case in from_base_index
+ // (and without the `map`, it does not).
+ let mut _set: HashSet<_> = (0..3).map(|_| ()).collect();
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-01 00:29:07 +0000