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use crate::indexmap::{self, IndexMap};
use core::{
borrow::Borrow,
fmt,
hash::{BuildHasher, Hash},
iter::FromIterator,
};
use hash32::{BuildHasherDefault, FnvHasher};
/// A [`IndexSet`] using the
/// default FNV hasher.
/// A list of all Methods and Traits available for `FnvIndexSet` can be found in
/// the [`IndexSet`] documentation.
///
/// # Examples
/// ```
/// use heapless::FnvIndexSet;
///
/// // A hash set with a capacity of 16 elements allocated on the stack
/// let mut books = FnvIndexSet::<_, 16>::new();
///
/// // Add some books.
/// books.insert("A Dance With Dragons").unwrap();
/// books.insert("To Kill a Mockingbird").unwrap();
/// books.insert("The Odyssey").unwrap();
/// books.insert("The Great Gatsby").unwrap();
///
/// // 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);
/// }
/// ```
pub type FnvIndexSet<T, const N: usize> = IndexSet<T, BuildHasherDefault<FnvHasher>, N>;
/// Fixed capacity [`IndexSet`](https://docs.rs/indexmap/2/indexmap/set/struct.IndexSet.html).
///
/// Note that you cannot use `IndexSet` directly, since it is generic around the hashing algorithm
/// in use. Pick a concrete instantiation like [`FnvIndexSet`] instead
/// or create your own.
///
/// Note that the capacity of the `IndexSet` must be a power of 2.
///
/// # Examples
/// Since `IndexSet` cannot be used directly, we're using its `FnvIndexSet` instantiation
/// for this example.
///
/// ```
/// use heapless::FnvIndexSet;
///
/// // A hash set with a capacity of 16 elements allocated on the stack
/// let mut books = FnvIndexSet::<_, 16>::new();
///
/// // Add some books.
/// books.insert("A Dance With Dragons").unwrap();
/// books.insert("To Kill a Mockingbird").unwrap();
/// books.insert("The Odyssey").unwrap();
/// books.insert("The Great Gatsby").unwrap();
///
/// // 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);
/// }
/// ```
pub struct IndexSet<T, S, const N: usize> {
map: IndexMap<T, (), S, N>,
}
impl<T, S, const N: usize> IndexSet<T, BuildHasherDefault<S>, N> {
/// Creates an empty `IndexSet`
pub const fn new() -> Self {
IndexSet {
map: IndexMap::new(),
}
}
}
impl<T, S, const N: usize> IndexSet<T, S, N> {
/// Returns the number of elements the set can hold
///
/// # Examples
///
/// ```
/// use heapless::FnvIndexSet;
///
/// let set = FnvIndexSet::<i32, 16>::new();
/// assert_eq!(set.capacity(), 16);
/// ```
pub fn capacity(&self) -> usize {
self.map.capacity()
}
/// Return an iterator over the values of the set, in insertion order
///
/// # Examples
///
/// ```
/// use heapless::FnvIndexSet;
///
/// let mut set = FnvIndexSet::<_, 16>::new();
/// set.insert("a").unwrap();
/// set.insert("b").unwrap();
///
/// // Will print in insertion order: a, b
/// for x in set.iter() {
/// println!("{}", x);
/// }
/// ```
pub fn iter(&self) -> Iter<'_, T> {
Iter {
iter: self.map.iter(),
}
}
/// Get the first value
///
/// Computes in **O(1)** time
pub fn first(&self) -> Option<&T> {
self.map.first().map(|(k, _v)| k)
}
/// Get the last value
///
/// Computes in **O(1)** time
pub fn last(&self) -> Option<&T> {
self.map.last().map(|(k, _v)| k)
}
/// Returns the number of elements in the set.
///
/// # Examples
///
/// ```
/// use heapless::FnvIndexSet;
///
/// let mut v: FnvIndexSet<_, 16> = FnvIndexSet::new();
/// assert_eq!(v.len(), 0);
/// v.insert(1).unwrap();
/// assert_eq!(v.len(), 1);
/// ```
pub fn len(&self) -> usize {
self.map.len()
}
/// Returns `true` if the set contains no elements.
///
/// # Examples
///
/// ```
/// use heapless::FnvIndexSet;
///
/// let mut v: FnvIndexSet<_, 16> = FnvIndexSet::new();
/// assert!(v.is_empty());
/// v.insert(1).unwrap();
/// assert!(!v.is_empty());
/// ```
pub fn is_empty(&self) -> bool {
self.map.is_empty()
}
/// Clears the set, removing all values.
///
/// # Examples
///
/// ```
/// use heapless::FnvIndexSet;
///
/// let mut v: FnvIndexSet<_, 16> = FnvIndexSet::new();
/// v.insert(1).unwrap();
/// v.clear();
/// assert!(v.is_empty());
/// ```
pub fn clear(&mut self) {
self.map.clear()
}
}
impl<T, S, const N: usize> IndexSet<T, S, N>
where
T: Eq + Hash,
S: BuildHasher,
{
/// Visits the values representing the difference, i.e. the values that are in `self` but not in
/// `other`.
///
/// # Examples
///
/// ```
/// use heapless::FnvIndexSet;
///
/// let mut a: FnvIndexSet<_, 16> = [1, 2, 3].iter().cloned().collect();
/// let mut b: FnvIndexSet<_, 16> = [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: FnvIndexSet<_, 16> = a.difference(&b).collect();
/// assert_eq!(diff, [1].iter().collect::<FnvIndexSet<_, 16>>());
///
/// // Note that difference is not symmetric,
/// // and `b - a` means something else:
/// let diff: FnvIndexSet<_, 16> = b.difference(&a).collect();
/// assert_eq!(diff, [4].iter().collect::<FnvIndexSet<_, 16>>());
/// ```
pub fn difference<'a, S2, const N2: usize>(
&'a self,
other: &'a IndexSet<T, S2, N2>,
) -> Difference<'a, T, S2, N2>
where
S2: BuildHasher,
{
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 heapless::FnvIndexSet;
///
/// let mut a: FnvIndexSet<_, 16> = [1, 2, 3].iter().cloned().collect();
/// let mut b: FnvIndexSet<_, 16> = [4, 2, 3, 4].iter().cloned().collect();
///
/// // Print 1, 4 in that order.
/// for x in a.symmetric_difference(&b) {
/// println!("{}", x);
/// }
///
/// let diff1: FnvIndexSet<_, 16> = a.symmetric_difference(&b).collect();
/// let diff2: FnvIndexSet<_, 16> = b.symmetric_difference(&a).collect();
///
/// assert_eq!(diff1, diff2);
/// assert_eq!(diff1, [1, 4].iter().collect::<FnvIndexSet<_, 16>>());
/// ```
pub fn symmetric_difference<'a, S2, const N2: usize>(
&'a self,
other: &'a IndexSet<T, S2, N2>,
) -> impl Iterator<Item = &'a T>
where
S2: BuildHasher,
{
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 heapless::FnvIndexSet;
///
/// let mut a: FnvIndexSet<_, 16> = [1, 2, 3].iter().cloned().collect();
/// let mut b: FnvIndexSet<_, 16> = [4, 2, 3, 4].iter().cloned().collect();
///
/// // Print 2, 3 in that order.
/// for x in a.intersection(&b) {
/// println!("{}", x);
/// }
///
/// let intersection: FnvIndexSet<_, 16> = a.intersection(&b).collect();
/// assert_eq!(intersection, [2, 3].iter().collect::<FnvIndexSet<_, 16>>());
/// ```
pub fn intersection<'a, S2, const N2: usize>(
&'a self,
other: &'a IndexSet<T, S2, N2>,
) -> Intersection<'a, T, S2, N2>
where
S2: BuildHasher,
{
Intersection {
iter: self.iter(),
other,
}
}
/// Visits the values representing the union, i.e. all the values in `self` or `other`, without
/// duplicates.
///
/// # Examples
///
/// ```
/// use heapless::FnvIndexSet;
///
/// let mut a: FnvIndexSet<_, 16> = [1, 2, 3].iter().cloned().collect();
/// let mut b: FnvIndexSet<_, 16> = [4, 2, 3, 4].iter().cloned().collect();
///
/// // Print 1, 2, 3, 4 in that order.
/// for x in a.union(&b) {
/// println!("{}", x);
/// }
///
/// let union: FnvIndexSet<_, 16> = a.union(&b).collect();
/// assert_eq!(union, [1, 2, 3, 4].iter().collect::<FnvIndexSet<_, 16>>());
/// ```
pub fn union<'a, S2, const N2: usize>(
&'a self,
other: &'a IndexSet<T, S2, N2>,
) -> impl Iterator<Item = &'a T>
where
S2: BuildHasher,
{
self.iter().chain(other.difference(self))
}
/// 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 heapless::FnvIndexSet;
///
/// let set: FnvIndexSet<_, 16> = [1, 2, 3].iter().cloned().collect();
/// assert_eq!(set.contains(&1), true);
/// assert_eq!(set.contains(&4), false);
/// ```
pub fn contains<Q>(&self, value: &Q) -> bool
where
T: Borrow<Q>,
Q: ?Sized + Eq + Hash,
{
self.map.contains_key(value)
}
/// Returns `true` if `self` has no elements in common with `other`. This is equivalent to
/// checking for an empty intersection.
///
/// # Examples
///
/// ```
/// use heapless::FnvIndexSet;
///
/// let a: FnvIndexSet<_, 16> = [1, 2, 3].iter().cloned().collect();
/// let mut b = FnvIndexSet::<_, 16>::new();
///
/// assert_eq!(a.is_disjoint(&b), true);
/// b.insert(4).unwrap();
/// assert_eq!(a.is_disjoint(&b), true);
/// b.insert(1).unwrap();
/// assert_eq!(a.is_disjoint(&b), false);
/// ```
pub fn is_disjoint<S2, const N2: usize>(&self, other: &IndexSet<T, S2, N2>) -> bool
where
S2: BuildHasher,
{
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 heapless::FnvIndexSet;
///
/// let sup: FnvIndexSet<_, 16> = [1, 2, 3].iter().cloned().collect();
/// let mut set = FnvIndexSet::<_, 16>::new();
///
/// assert_eq!(set.is_subset(&sup), true);
/// set.insert(2).unwrap();
/// assert_eq!(set.is_subset(&sup), true);
/// set.insert(4).unwrap();
/// assert_eq!(set.is_subset(&sup), false);
/// ```
pub fn is_subset<S2, const N2: usize>(&self, other: &IndexSet<T, S2, N2>) -> bool
where
S2: BuildHasher,
{
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 heapless::FnvIndexSet;
///
/// let sub: FnvIndexSet<_, 16> = [1, 2].iter().cloned().collect();
/// let mut set = FnvIndexSet::<_, 16>::new();
///
/// assert_eq!(set.is_superset(&sub), false);
///
/// set.insert(0).unwrap();
/// set.insert(1).unwrap();
/// assert_eq!(set.is_superset(&sub), false);
///
/// set.insert(2).unwrap();
/// assert_eq!(set.is_superset(&sub), true);
/// ```
pub fn is_superset<S2, const N2: usize>(&self, other: &IndexSet<T, S2, N2>) -> bool
where
S2: BuildHasher,
{
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 heapless::FnvIndexSet;
///
/// let mut set = FnvIndexSet::<_, 16>::new();
///
/// assert_eq!(set.insert(2).unwrap(), true);
/// assert_eq!(set.insert(2).unwrap(), false);
/// assert_eq!(set.len(), 1);
/// ```
pub fn insert(&mut self, value: T) -> Result<bool, T> {
self.map
.insert(value, ())
.map(|old| old.is_none())
.map_err(|(k, _)| k)
}
/// Removes a value from the set. Returns `true` if 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 heapless::FnvIndexSet;
///
/// let mut set = FnvIndexSet::<_, 16>::new();
///
/// set.insert(2).unwrap();
/// assert_eq!(set.remove(&2), true);
/// assert_eq!(set.remove(&2), false);
/// ```
pub fn remove<Q>(&mut self, value: &Q) -> bool
where
T: Borrow<Q>,
Q: ?Sized + Eq + Hash,
{
self.map.remove(value).is_some()
}
/// Retains only the elements specified by the predicate.
///
/// In other words, remove all elements `e` for which `f(&e)` returns `false`.
pub fn retain<F>(&mut self, mut f: F)
where
F: FnMut(&T) -> bool,
{
self.map.retain(move |k, _| f(k));
}
}
impl<T, S, const N: usize> Clone for IndexSet<T, S, N>
where
T: Clone,
S: Clone,
{
fn clone(&self) -> Self {
Self {
map: self.map.clone(),
}
}
}
impl<T, S, const N: usize> fmt::Debug for IndexSet<T, S, N>
where
T: fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_set().entries(self.iter()).finish()
}
}
impl<T, S, const N: usize> Default for IndexSet<T, S, N>
where
S: Default,
{
fn default() -> Self {
IndexSet {
map: <_>::default(),
}
}
}
impl<T, S1, S2, const N1: usize, const N2: usize> PartialEq<IndexSet<T, S2, N2>>
for IndexSet<T, S1, N1>
where
T: Eq + Hash,
S1: BuildHasher,
S2: BuildHasher,
{
fn eq(&self, other: &IndexSet<T, S2, N2>) -> bool {
self.len() == other.len() && self.is_subset(other)
}
}
impl<T, S, const N: usize> Extend<T> for IndexSet<T, S, N>
where
T: Eq + Hash,
S: BuildHasher,
{
fn extend<I>(&mut self, iterable: I)
where
I: IntoIterator<Item = T>,
{
self.map.extend(iterable.into_iter().map(|k| (k, ())))
}
}
impl<'a, T, S, const N: usize> Extend<&'a T> for IndexSet<T, S, N>
where
T: 'a + Eq + Hash + Copy,
S: BuildHasher,
{
fn extend<I>(&mut self, iterable: I)
where
I: IntoIterator<Item = &'a T>,
{
self.extend(iterable.into_iter().cloned())
}
}
impl<T, S, const N: usize> FromIterator<T> for IndexSet<T, S, N>
where
T: Eq + Hash,
S: BuildHasher + Default,
{
fn from_iter<I>(iter: I) -> Self
where
I: IntoIterator<Item = T>,
{
let mut set = IndexSet::default();
set.extend(iter);
set
}
}
impl<'a, T, S, const N: usize> IntoIterator for &'a IndexSet<T, S, N>
where
T: Eq + Hash,
S: BuildHasher,
{
type Item = &'a T;
type IntoIter = Iter<'a, T>;
fn into_iter(self) -> Self::IntoIter {
self.iter()
}
}
/// An iterator over the items of a [`IndexSet`].
///
/// This `struct` is created by the [`iter`](IndexSet::iter) method on [`IndexSet`]. See its
/// documentation for more.
pub struct Iter<'a, T> {
iter: indexmap::Iter<'a, T, ()>,
}
impl<'a, T> Iterator for Iter<'a, T> {
type Item = &'a T;
fn next(&mut self) -> Option<Self::Item> {
self.iter.next().map(|(k, _)| k)
}
}
impl<'a, T> Clone for Iter<'a, T> {
fn clone(&self) -> Self {
Self {
iter: self.iter.clone(),
}
}
}
pub struct Difference<'a, T, S, const N: usize>
where
S: BuildHasher,
T: Eq + Hash,
{
iter: Iter<'a, T>,
other: &'a IndexSet<T, S, N>,
}
impl<'a, T, S, const N: usize> Iterator for Difference<'a, T, S, N>
where
S: BuildHasher,
T: Eq + Hash,
{
type Item = &'a T;
fn next(&mut self) -> Option<Self::Item> {
loop {
let elt = self.iter.next()?;
if !self.other.contains(elt) {
return Some(elt);
}
}
}
}
pub struct Intersection<'a, T, S, const N: usize>
where
S: BuildHasher,
T: Eq + Hash,
{
iter: Iter<'a, T>,
other: &'a IndexSet<T, S, N>,
}
impl<'a, T, S, const N: usize> Iterator for Intersection<'a, T, S, N>
where
S: BuildHasher,
T: Eq + Hash,
{
type Item = &'a T;
fn next(&mut self) -> Option<Self::Item> {
loop {
let elt = self.iter.next()?;
if self.other.contains(elt) {
return Some(elt);
}
}
}
}