#[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, FusedIterator};
use core::ops::{BitAnd, BitOr, BitXor, Sub};
use super::map::{self, DefaultHashBuilder, HashMap, Keys};
use crate::raw::{Allocator, Global, RawExtractIf};
// 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" ].into_iter().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].into_iter().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.into_iter().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.
///
/// [`retain()`]: HashSet::retain
///
/// # 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: RawExtractIf {
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].into_iter().collect();
/// let b: HashSet<_> = [4, 2, 3, 4].into_iter().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].into_iter().collect();
/// let b: HashSet<_> = [4, 2, 3, 4].into_iter().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].into_iter().collect();
/// let b: HashSet<_> = [4, 2, 3, 4].into_iter().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].into_iter().collect();
/// let b: HashSet<_> = [4, 2, 3, 4].into_iter().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].into_iter().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].into_iter().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].into_iter().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].into_iter().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].into_iter().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].into_iter().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].into_iter().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: RawExtractIf<'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()
}
#[cfg_attr(feature = "inline-more", inline)]
fn fold<B, F>(self, init: B, f: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
self.iter.fold(init, f)
}
}
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()
}
#[cfg_attr(feature = "inline-more", inline)]
fn fold<B, F>(self, init: B, mut f: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
self.iter.fold(init, |acc, (k, ())| f(acc, k))
}
}
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()
}
#[cfg_attr(feature = "inline-more", inline)]
fn fold<B, F>(self, init: B, mut f: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
self.iter.fold(init, |acc, (k, ())| f(acc, k))
}
}
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> {
self.inner
.next(|&mut (ref k, ())| (self.f)(k))
.map(|(k, ())| 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)
}
#[cfg_attr(feature = "inline-more", inline)]
fn fold<B, F>(self, init: B, mut f: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
self.iter.fold(init, |acc, elt| {
if self.other.contains(elt) {
f(acc, elt)
} else {
acc
}
})
}
}
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)
}
#[cfg_attr(feature = "inline-more", inline)]
fn fold<B, F>(self, init: B, mut f: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
self.iter.fold(init, |acc, elt| {
if self.other.contains(elt) {
acc
} else {
f(acc, elt)
}
})
}
}
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()
}
#[cfg_attr(feature = "inline-more", inline)]
fn fold<B, F>(self, init: B, f: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
self.iter.fold(init, f)
}
}
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()
}
#[cfg_attr(feature = "inline-more", inline)]
fn fold<B, F>(self, init: B, f: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
self.iter.fold(init, f)
}
}
/// 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(_) => { }
/// }
--> --------------------
--> maximum size reached
--> --------------------
