use crate::TryReserveError;
use core::borrow::Borrow;
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, HashMap, Keys};
// 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 griddle::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 griddle::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 griddle::HashSet;
///
/// fn main() {
/// 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> {
pub(crate) map: HashMap<T, (), S>,
}
impl<T: Clone, S: Clone> Clone for HashSet<T, S> {
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: Hash + Eq> 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.
///
/// # Examples
///
/// ```
/// use griddle::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.
///
/// # Examples
///
/// ```
/// use griddle::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),
}
}
}
impl<T, S> HashSet<T, S> {
/// Returns the number of elements the set can hold without reallocating.
///
/// # Examples
///
/// ```
/// use griddle::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 griddle::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 griddle::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 griddle::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()
}
/// Retains only the elements specified by the predicate.
///
/// In other words, remove all elements `e` such that `f(&e)` returns `false`.
///
/// # Examples
///
/// ```
/// use griddle::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));
}
/// Clears the set, removing all values.
///
/// # Examples
///
/// ```
/// use griddle::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>
where
T: Eq + Hash,
S: BuildHasher,
{
/// Creates a new empty hash set which will use the given hasher to hash
/// keys.
///
/// The hash set is also created with the default initial capacity.
///
/// Warning: `hasher` is normally randomly generated, and
/// is designed to allow `HashSet`s to be resistant to attacks that
/// cause many collisions and very poor performance. Setting it
/// manually using this function can expose a DoS attack vector.
///
/// The `hash_builder` passed should implement the [`BuildHasher`] trait for
/// the HashMap to be useful, see its documentation for details.
///
///
/// # Examples
///
/// ```
/// use griddle::HashSet;
/// use griddle::hash_map::DefaultHashBuilder;
///
/// let s = DefaultHashBuilder::default();
/// let mut set = HashSet::with_hasher(s);
/// set.insert(2);
/// ```
///
/// [`BuildHasher`]: ../../std/hash/trait.BuildHasher.html
#[cfg_attr(feature = "inline-more", inline)]
pub 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.
///
/// Warning: `hasher` is normally randomly generated, and
/// is designed to allow `HashSet`s to be resistant to attacks that
/// cause many collisions and very poor performance. Setting it
/// manually using this function can expose a DoS attack vector.
///
/// The `hash_builder` passed should implement the [`BuildHasher`] trait for
/// the HashMap to be useful, see its documentation for details.
///
/// # Examples
///
/// ```
/// use griddle::HashSet;
/// use griddle::hash_map::DefaultHashBuilder;
///
/// let s = DefaultHashBuilder::default();
/// let mut set = HashSet::with_capacity_and_hasher(10, s);
/// set.insert(1);
/// ```
///
/// [`BuildHasher`]: ../../std/hash/trait.BuildHasher.html
#[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),
}
}
/// Returns a reference to the set's [`BuildHasher`].
///
/// [`BuildHasher`]: https://doc.rust-lang.org/std/hash/trait.BuildHasher.html
///
/// # Examples
///
/// ```
/// use griddle::HashSet;
/// use griddle::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()
}
/// 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 allocation size overflows `usize`.
///
/// # Examples
///
/// ```
/// use griddle::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 griddle::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 griddle::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 griddle::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 griddle::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> {
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 griddle::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> {
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 griddle::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> {
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 griddle::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> {
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 griddle::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
T: Borrow<Q>,
Q: Hash + Eq,
{
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 griddle::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
T: Borrow<Q>,
Q: Hash + Eq,
{
self.map.get_key_value(value).map(|(k, _)| k)
}
/// Returns `true` if `self` has no elements in common with `other`.
/// This is equivalent to checking for an empty intersection.
///
/// # Examples
///
/// ```
/// use griddle::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 griddle::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 griddle::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 griddle::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()
}
/// 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 griddle::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
T: Borrow<Q>,
Q: Hash + Eq,
{
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 griddle::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
T: Borrow<Q>,
Q: Hash + Eq,
{
self.map.remove_entry(value).map(|(k, _)| k)
}
}
impl<T, S> PartialEq for HashSet<T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
fn eq(&self, other: &Self) -> bool {
if self.len() != other.len() {
return false;
}
self.iter().all(|key| other.contains(key))
}
}
impl<T, S> Eq for HashSet<T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
}
impl<T, S> fmt::Debug for HashSet<T, S>
where
T: Eq + Hash + fmt::Debug,
S: BuildHasher,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_set().entries(self.iter()).finish()
}
}
impl<T, S> FromIterator<T> for HashSet<T, S>
where
T: Eq + Hash,
S: BuildHasher + Default,
{
#[cfg_attr(feature = "inline-more", inline)]
fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self {
let mut set = Self::with_hasher(Default::default());
set.extend(iter);
set
}
}
impl<T, S> Extend<T> for HashSet<T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
#[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> Extend<&'a T> for HashSet<T, S>
where
T: 'a + Eq + Hash + Copy,
S: BuildHasher,
{
#[cfg_attr(feature = "inline-more", inline)]
fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) {
self.extend(iter.into_iter().cloned());
}
#[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> Default for HashSet<T, S>
where
S: Default,
{
/// 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> BitOr<&HashSet<T, S>> for &HashSet<T, S>
where
T: Eq + Hash + Clone,
S: BuildHasher + Default,
{
type Output = HashSet<T, S>;
/// Returns the union of `self` and `rhs` as a new `HashSet<T, S>`.
///
/// # Examples
///
/// ```
/// use griddle::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>) -> HashSet<T, S> {
self.union(rhs).cloned().collect()
}
}
impl<T, S> BitAnd<&HashSet<T, S>> for &HashSet<T, S>
where
T: Eq + Hash + Clone,
S: BuildHasher + Default,
{
type Output = HashSet<T, S>;
/// Returns the intersection of `self` and `rhs` as a new `HashSet<T, S>`.
///
/// # Examples
///
/// ```
/// use griddle::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>) -> 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 griddle::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 griddle::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> {
iter: map::IntoIter<K, ()>,
}
/// 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> {
// iterator of the first set
iter: Iter<'a, T>,
// the second set
other: &'a HashSet<T, S>,
}
/// 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> {
// iterator of the first set
iter: Iter<'a, T>,
// the second set
other: &'a HashSet<T, S>,
}
/// 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> {
iter: Chain<Difference<'a, T, S>, Difference<'a, T, S>>,
}
/// 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> {
iter: Chain<Iter<'a, T>, Difference<'a, T, S>>,
}
impl<'a, T, S> IntoIterator for &'a HashSet<T, S> {
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> IntoIterator for HashSet<T, S> {
type Item = T;
type IntoIter = IntoIter<T>;
/// 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 griddle::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> {
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> Iterator for IntoIter<K> {
type Item = K;
#[cfg_attr(feature = "inline-more", inline)]
fn next(&mut self) -> Option<K> {
self.iter.next().map(|(k, _)| k)
}
#[cfg_attr(feature = "inline-more", inline)]
fn size_hint(&self) -> (usize, Option<usize>) {
self.iter.size_hint()
}
}
impl<K> ExactSizeIterator for IntoIter<K> {
#[cfg_attr(feature = "inline-more", inline)]
fn len(&self) -> usize {
self.iter.len()
}
}
impl<K> FusedIterator for IntoIter<K> {}
impl<K: fmt::Debug> fmt::Debug for IntoIter<K> {
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<T, S> Clone for Intersection<'_, T, S> {
#[cfg_attr(feature = "inline-more", inline)]
fn clone(&self) -> Self {
Intersection {
iter: self.iter.clone(),
..*self
}
}
}
impl<'a, T, S> Iterator for Intersection<'a, T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
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> fmt::Debug for Intersection<'_, T, S>
where
T: fmt::Debug + Eq + Hash,
S: BuildHasher,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_list().entries(self.clone()).finish()
}
}
impl<T, S> FusedIterator for Intersection<'_, T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
}
impl<T, S> Clone for Difference<'_, T, S> {
#[cfg_attr(feature = "inline-more", inline)]
fn clone(&self) -> Self {
Difference {
iter: self.iter.clone(),
..*self
}
}
}
impl<'a, T, S> Iterator for Difference<'a, T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
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> FusedIterator for Difference<'_, T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
}
impl<T, S> fmt::Debug for Difference<'_, T, S>
where
T: fmt::Debug + Eq + Hash,
S: BuildHasher,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_list().entries(self.clone()).finish()
}
}
impl<T, S> Clone for SymmetricDifference<'_, T, S> {
#[cfg_attr(feature = "inline-more", inline)]
fn clone(&self) -> Self {
SymmetricDifference {
iter: self.iter.clone(),
}
}
}
impl<'a, T, S> Iterator for SymmetricDifference<'a, T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
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> FusedIterator for SymmetricDifference<'_, T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
}
impl<T, S> fmt::Debug for SymmetricDifference<'_, T, S>
where
T: fmt::Debug + Eq + Hash,
S: BuildHasher,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_list().entries(self.clone()).finish()
}
}
impl<T, S> Clone for Union<'_, T, S> {
#[cfg_attr(feature = "inline-more", inline)]
fn clone(&self) -> Self {
Union {
iter: self.iter.clone(),
}
}
}
impl<T, S> FusedIterator for Union<'_, T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
}
impl<T, S> fmt::Debug for Union<'_, T, S>
where
T: fmt::Debug + Eq + Hash,
S: BuildHasher,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_list().entries(self.clone()).finish()
}
}
impl<'a, T, S> Iterator for Union<'a, T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
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()
}
}
#[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>(v: IntoIter<&'static str>) -> IntoIter<&'new str> {
v
}
fn difference<'a, 'new>(
v: Difference<'a, &'static str, DefaultHashBuilder>,
) -> Difference<'a, &'new str, DefaultHashBuilder> {
v
}
fn symmetric_difference<'a, 'new>(
v: SymmetricDifference<'a, &'static str, DefaultHashBuilder>,
) -> SymmetricDifference<'a, &'new str, DefaultHashBuilder> {
v
}
fn intersection<'a, 'new>(
v: Intersection<'a, &'static str, DefaultHashBuilder>,
) -> Intersection<'a, &'new str, DefaultHashBuilder> {
v
}
fn union<'a, 'new>(
v: Union<'a, &'static str, DefaultHashBuilder>,
) -> Union<'a, &'new str, DefaultHashBuilder> {
v
}
}
#[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_iter() {
let xs = [1, 2, 2, 3, 4, 5, 6, 7, 8, 9];
let set: HashSet<_> = xs.iter().cloned().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_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().cloned().collect();
set.retain(|&k| k % 2 == 0);
assert_eq!(set.len(), 3);
assert!(set.contains(&2));
assert!(set.contains(&4));
assert!(set.contains(&6));
}
}