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//! A hash set implemented using [`IndexMap`]
mod iter;
mod mutable;
mod slice;
#[cfg(test)]
mod tests;
pub use self::iter::{
Difference, Drain, Intersection, IntoIter, Iter, Splice, SymmetricDifference, Union,
};
pub use self::mutable::MutableValues;
pub use self::slice::Slice;
#[cfg(feature = "rayon")]
pub use crate::rayon::set as rayon;
use crate::TryReserveError;
#[cfg(feature = "std")]
use std::collections::hash_map::RandomState;
use crate::util::try_simplify_range;
use alloc::boxed::Box;
use alloc::vec::Vec;
use core::cmp::Ordering;
use core::fmt;
use core::hash::{BuildHasher, Hash};
use core::ops::{BitAnd, BitOr, BitXor, Index, RangeBounds, Sub};
use super::{Entries, Equivalent, IndexMap};
type Bucket<T> = super::Bucket<T, ()>;
/// A hash set where the iteration order of the values is independent of their
/// hash values.
///
/// The interface is closely compatible with the standard
/// [`HashSet`][std::collections::HashSet],
/// but also has additional features.
///
/// # Order
///
/// The values have a consistent order that is determined by the sequence of
/// insertion and removal calls on the set. The order does not depend on the
/// values or the hash function at all. Note that insertion order and value
/// are not affected if a re-insertion is attempted once an element is
/// already present.
///
/// All iterators traverse the set *in order*. Set operation iterators like
/// [`IndexSet::union`] produce a concatenated order, as do their matching "bitwise"
/// operators. See their documentation for specifics.
///
/// The insertion order is preserved, with **notable exceptions** like the
/// [`.remove()`][Self::remove] or [`.swap_remove()`][Self::swap_remove] methods.
/// Methods such as [`.sort_by()`][Self::sort_by] of
/// course result in a new order, depending on the sorting order.
///
/// # Indices
///
/// The values are indexed in a compact range without holes in the range
/// `0..self.len()`. For example, the method `.get_full` looks up the index for
/// a value, and the method `.get_index` looks up the value by index.
///
/// # Complexity
///
/// Internally, `IndexSet<T, S>` just holds an [`IndexMap<T, (), S>`](IndexMap). Thus the complexity
/// of the two are the same for most methods.
///
/// # Examples
///
/// ```
/// use indexmap::IndexSet;
///
/// // Collects which letters appear in a sentence.
/// let letters: IndexSet<_> = "a short treatise on fungi".chars().collect();
///
/// assert!(letters.contains(&'s'));
/// assert!(letters.contains(&'t'));
/// assert!(letters.contains(&'u'));
/// assert!(!letters.contains(&'y'));
/// ```
#[cfg(feature = "std")]
pub struct IndexSet<T, S = RandomState> {
pub(crate) map: IndexMap<T, (), S>,
}
#[cfg(not(feature = "std"))]
pub struct IndexSet<T, S> {
pub(crate) map: IndexMap<T, (), S>,
}
impl<T, S> Clone for IndexSet<T, S>
where
T: Clone,
S: Clone,
{
fn clone(&self) -> Self {
IndexSet {
map: self.map.clone(),
}
}
fn clone_from(&mut self, other: &Self) {
self.map.clone_from(&other.map);
}
}
impl<T, S> Entries for IndexSet<T, S> {
type Entry = Bucket<T>;
#[inline]
fn into_entries(self) -> Vec<Self::Entry> {
self.map.into_entries()
}
#[inline]
fn as_entries(&self) -> &[Self::Entry] {
self.map.as_entries()
}
#[inline]
fn as_entries_mut(&mut self) -> &mut [Self::Entry] {
self.map.as_entries_mut()
}
fn with_entries<F>(&mut self, f: F)
where
F: FnOnce(&mut [Self::Entry]),
{
self.map.with_entries(f);
}
}
impl<T, S> fmt::Debug for IndexSet<T, S>
where
T: fmt::Debug,
{
#[cfg(not(feature = "test_debug"))]
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_set().entries(self.iter()).finish()
}
#[cfg(feature = "test_debug")]
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
// Let the inner `IndexMap` print all of its details
f.debug_struct("IndexSet").field("map", &self.map).finish()
}
}
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
impl<T> IndexSet<T> {
/// Create a new set. (Does not allocate.)
pub fn new() -> Self {
IndexSet {
map: IndexMap::new(),
}
}
/// Create a new set with capacity for `n` elements.
/// (Does not allocate if `n` is zero.)
///
/// Computes in **O(n)** time.
pub fn with_capacity(n: usize) -> Self {
IndexSet {
map: IndexMap::with_capacity(n),
}
}
}
impl<T, S> IndexSet<T, S> {
/// Create a new set with capacity for `n` elements.
/// (Does not allocate if `n` is zero.)
///
/// Computes in **O(n)** time.
pub fn with_capacity_and_hasher(n: usize, hash_builder: S) -> Self {
IndexSet {
map: IndexMap::with_capacity_and_hasher(n, hash_builder),
}
}
/// Create a new set with `hash_builder`.
///
/// This function is `const`, so it
/// can be called in `static` contexts.
pub const fn with_hasher(hash_builder: S) -> Self {
IndexSet {
map: IndexMap::with_hasher(hash_builder),
}
}
/// Return the number of elements the set can hold without reallocating.
///
/// This number is a lower bound; the set might be able to hold more,
/// but is guaranteed to be able to hold at least this many.
///
/// Computes in **O(1)** time.
pub fn capacity(&self) -> usize {
self.map.capacity()
}
/// Return a reference to the set's `BuildHasher`.
pub fn hasher(&self) -> &S {
self.map.hasher()
}
/// Return the number of elements in the set.
///
/// Computes in **O(1)** time.
pub fn len(&self) -> usize {
self.map.len()
}
/// Returns true if the set contains no elements.
///
/// Computes in **O(1)** time.
pub fn is_empty(&self) -> bool {
self.map.is_empty()
}
/// Return an iterator over the values of the set, in their order
pub fn iter(&self) -> Iter<'_, T> {
Iter::new(self.as_entries())
}
/// Remove all elements in the set, while preserving its capacity.
///
/// Computes in **O(n)** time.
pub fn clear(&mut self) {
self.map.clear();
}
/// Shortens the set, keeping the first `len` elements and dropping the rest.
///
/// If `len` is greater than the set's current length, this has no effect.
pub fn truncate(&mut self, len: usize) {
self.map.truncate(len);
}
/// Clears the `IndexSet` in the given index range, returning those values
/// as a drain iterator.
///
/// The range may be any type that implements [`RangeBounds<usize>`],
/// including all of the `std::ops::Range*` types, or even a tuple pair of
/// `Bound` start and end values. To drain the set entirely, use `RangeFull`
/// like `set.drain(..)`.
///
/// This shifts down all entries following the drained range to fill the
/// gap, and keeps the allocated memory for reuse.
///
/// ***Panics*** if the starting point is greater than the end point or if
/// the end point is greater than the length of the set.
pub fn drain<R>(&mut self, range: R) -> Drain<'_, T>
where
R: RangeBounds<usize>,
{
Drain::new(self.map.core.drain(range))
}
/// Splits the collection into two at the given index.
///
/// Returns a newly allocated set containing the elements in the range
/// `[at, len)`. After the call, the original set will be left containing
/// the elements `[0, at)` with its previous capacity unchanged.
///
/// ***Panics*** if `at > len`.
pub fn split_off(&mut self, at: usize) -> Self
where
S: Clone,
{
Self {
map: self.map.split_off(at),
}
}
/// Reserve capacity for `additional` more values.
///
/// Computes in **O(n)** time.
pub fn reserve(&mut self, additional: usize) {
self.map.reserve(additional);
}
/// Reserve capacity for `additional` more values, without over-allocating.
///
/// Unlike `reserve`, this does not deliberately over-allocate the entry capacity to avoid
/// frequent re-allocations. However, the underlying data structures may still have internal
/// capacity requirements, and the allocator itself may give more space than requested, so this
/// cannot be relied upon to be precisely minimal.
///
/// Computes in **O(n)** time.
pub fn reserve_exact(&mut self, additional: usize) {
self.map.reserve_exact(additional);
}
/// Try to reserve capacity for `additional` more values.
///
/// Computes in **O(n)** time.
pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
self.map.try_reserve(additional)
}
/// Try to reserve capacity for `additional` more values, without over-allocating.
///
/// Unlike `try_reserve`, this does not deliberately over-allocate the entry capacity to avoid
/// frequent re-allocations. However, the underlying data structures may still have internal
/// capacity requirements, and the allocator itself may give more space than requested, so this
/// cannot be relied upon to be precisely minimal.
///
/// Computes in **O(n)** time.
pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError> {
self.map.try_reserve_exact(additional)
}
/// Shrink the capacity of the set as much as possible.
///
/// Computes in **O(n)** time.
pub fn shrink_to_fit(&mut self) {
self.map.shrink_to_fit();
}
/// Shrink the capacity of the set with a lower limit.
///
/// Computes in **O(n)** time.
pub fn shrink_to(&mut self, min_capacity: usize) {
self.map.shrink_to(min_capacity);
}
}
impl<T, S> IndexSet<T, S>
where
T: Hash + Eq,
S: BuildHasher,
{
/// Insert the value into the set.
///
/// If an equivalent item already exists in the set, it returns
/// `false` leaving the original value in the set and without
/// altering its insertion order. Otherwise, it inserts the new
/// item and returns `true`.
///
/// Computes in **O(1)** time (amortized average).
pub fn insert(&mut self, value: T) -> bool {
self.map.insert(value, ()).is_none()
}
/// Insert the value into the set, and get its index.
///
/// If an equivalent item already exists in the set, it returns
/// the index of the existing item and `false`, leaving the
/// original value in the set and without altering its insertion
/// order. Otherwise, it inserts the new item and returns the index
/// of the inserted item and `true`.
///
/// Computes in **O(1)** time (amortized average).
pub fn insert_full(&mut self, value: T) -> (usize, bool) {
let (index, existing) = self.map.insert_full(value, ());
(index, existing.is_none())
}
/// Insert the value into the set at its ordered position among sorted values.
///
/// This is equivalent to finding the position with
/// [`binary_search`][Self::binary_search], and if needed calling
/// [`shift_insert`][Self::shift_insert] for a new value.
///
/// If the sorted item is found in the set, it returns the index of that
/// existing item and `false`, without any change. Otherwise, it inserts the
/// new item and returns its sorted index and `true`.
///
/// If the existing items are **not** already sorted, then the insertion
/// index is unspecified (like [`slice::binary_search`]), but the value
/// is moved to or inserted at that position regardless.
///
/// Computes in **O(n)** time (average). Instead of repeating calls to
/// `insert_sorted`, it may be faster to call batched [`insert`][Self::insert]
/// or [`extend`][Self::extend] and only call [`sort`][Self::sort] or
/// [`sort_unstable`][Self::sort_unstable] once.
pub fn insert_sorted(&mut self, value: T) -> (usize, bool)
where
T: Ord,
{
let (index, existing) = self.map.insert_sorted(value, ());
(index, existing.is_none())
}
/// Insert the value into the set at the given index.
///
/// If an equivalent item already exists in the set, it returns
/// `false` leaving the original value in the set, but moving it to
/// the new position in the set. Otherwise, it inserts the new
/// item at the given index and returns `true`.
///
/// ***Panics*** if `index` is out of bounds.
///
/// Computes in **O(n)** time (average).
pub fn shift_insert(&mut self, index: usize, value: T) -> bool {
self.map.shift_insert(index, value, ()).is_none()
}
/// Adds a value to the set, replacing the existing value, if any, that is
/// equal to the given one, without altering its insertion order. Returns
/// the replaced value.
///
/// Computes in **O(1)** time (average).
pub fn replace(&mut self, value: T) -> Option<T> {
self.replace_full(value).1
}
/// Adds a value to the set, replacing the existing value, if any, that is
/// equal to the given one, without altering its insertion order. Returns
/// the index of the item and its replaced value.
///
/// Computes in **O(1)** time (average).
pub fn replace_full(&mut self, value: T) -> (usize, Option<T>) {
let hash = self.map.hash(&value);
match self.map.core.replace_full(hash, value, ()) {
(i, Some((replaced, ()))) => (i, Some(replaced)),
(i, None) => (i, None),
}
}
/// Return an iterator over the values that are in `self` but not `other`.
///
/// Values are produced in the same order that they appear in `self`.
pub fn difference<'a, S2>(&'a self, other: &'a IndexSet<T, S2>) -> Difference<'a, T, S2>
where
S2: BuildHasher,
{
Difference::new(self, other)
}
/// Return an iterator over the values that are in `self` or `other`,
/// but not in both.
///
/// Values from `self` are produced in their original order, followed by
/// values from `other` in their original order.
pub fn symmetric_difference<'a, S2>(
&'a self,
other: &'a IndexSet<T, S2>,
) -> SymmetricDifference<'a, T, S, S2>
where
S2: BuildHasher,
{
SymmetricDifference::new(self, other)
}
/// Return an iterator over the values that are in both `self` and `other`.
///
/// Values are produced in the same order that they appear in `self`.
pub fn intersection<'a, S2>(&'a self, other: &'a IndexSet<T, S2>) -> Intersection<'a, T, S2>
where
S2: BuildHasher,
{
Intersection::new(self, other)
}
/// Return an iterator over all values that are in `self` or `other`.
///
/// Values from `self` are produced in their original order, followed by
/// values that are unique to `other` in their original order.
pub fn union<'a, S2>(&'a self, other: &'a IndexSet<T, S2>) -> Union<'a, T, S>
where
S2: BuildHasher,
{
Union::new(self, other)
}
/// Creates a splicing iterator that replaces the specified range in the set
/// with the given `replace_with` iterator and yields the removed items.
/// `replace_with` does not need to be the same length as `range`.
///
/// The `range` is removed even if the iterator is not consumed until the
/// end. It is unspecified how many elements are removed from the set if the
/// `Splice` value is leaked.
///
/// The input iterator `replace_with` is only consumed when the `Splice`
/// value is dropped. If a value from the iterator matches an existing entry
/// in the set (outside of `range`), then the original will be unchanged.
/// Otherwise, the new value will be inserted in the replaced `range`.
///
/// ***Panics*** if the starting point is greater than the end point or if
/// the end point is greater than the length of the set.
///
/// # Examples
///
/// ```
/// use indexmap::IndexSet;
///
/// let mut set = IndexSet::from([0, 1, 2, 3, 4]);
/// let new = [5, 4, 3, 2, 1];
/// let removed: Vec<_> = set.splice(2..4, new).collect();
///
/// // 1 and 4 kept their positions, while 5, 3, and 2 were newly inserted.
/// assert!(set.into_iter().eq([0, 1, 5, 3, 2, 4]));
/// assert_eq!(removed, &[2, 3]);
/// ```
pub fn splice<R, I>(&mut self, range: R, replace_with: I) -> Splice<'_, I::IntoIter, T, S>
where
R: RangeBounds<usize>,
I: IntoIterator<Item = T>,
{
Splice::new(self, range, replace_with.into_iter())
}
}
impl<T, S> IndexSet<T, S>
where
S: BuildHasher,
{
/// Return `true` if an equivalent to `value` exists in the set.
///
/// Computes in **O(1)** time (average).
pub fn contains<Q>(&self, value: &Q) -> bool
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.map.contains_key(value)
}
/// Return a reference to the value stored in the set, if it is present,
/// else `None`.
///
/// Computes in **O(1)** time (average).
pub fn get<Q>(&self, value: &Q) -> Option<&T>
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.map.get_key_value(value).map(|(x, &())| x)
}
/// Return item index and value
pub fn get_full<Q>(&self, value: &Q) -> Option<(usize, &T)>
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.map.get_full(value).map(|(i, x, &())| (i, x))
}
/// Return item index, if it exists in the set
///
/// Computes in **O(1)** time (average).
pub fn get_index_of<Q>(&self, value: &Q) -> Option<usize>
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.map.get_index_of(value)
}
/// Remove the value from the set, and return `true` if it was present.
///
/// **NOTE:** This is equivalent to [`.swap_remove(value)`][Self::swap_remove], replacing this
/// value's position with the last element, and it is deprecated in favor of calling that
/// explicitly. If you need to preserve the relative order of the values in the set, use
/// [`.shift_remove(value)`][Self::shift_remove] instead.
#[deprecated(note = "`remove` disrupts the set order -- \
use `swap_remove` or `shift_remove` for explicit behavior.")]
pub fn remove<Q>(&mut self, value: &Q) -> bool
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.swap_remove(value)
}
/// Remove the value from the set, and return `true` if it was present.
///
/// Like [`Vec::swap_remove`], the value is removed by swapping it with the
/// last element of the set and popping it off. **This perturbs
/// the position of what used to be the last element!**
///
/// Return `false` if `value` was not in the set.
///
/// Computes in **O(1)** time (average).
pub fn swap_remove<Q>(&mut self, value: &Q) -> bool
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.map.swap_remove(value).is_some()
}
/// Remove the value from the set, and return `true` if it was present.
///
/// Like [`Vec::remove`], the value is removed by shifting all of the
/// elements that follow it, preserving their relative order.
/// **This perturbs the index of all of those elements!**
///
/// Return `false` if `value` was not in the set.
///
/// Computes in **O(n)** time (average).
pub fn shift_remove<Q>(&mut self, value: &Q) -> bool
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.map.shift_remove(value).is_some()
}
/// Removes and returns the value in the set, if any, that is equal to the
/// given one.
///
/// **NOTE:** This is equivalent to [`.swap_take(value)`][Self::swap_take], replacing this
/// value's position with the last element, and it is deprecated in favor of calling that
/// explicitly. If you need to preserve the relative order of the values in the set, use
/// [`.shift_take(value)`][Self::shift_take] instead.
#[deprecated(note = "`take` disrupts the set order -- \
use `swap_take` or `shift_take` for explicit behavior.")]
pub fn take<Q>(&mut self, value: &Q) -> Option<T>
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.swap_take(value)
}
/// Removes and returns the value in the set, if any, that is equal to the
/// given one.
///
/// Like [`Vec::swap_remove`], the value is removed by swapping it with the
/// last element of the set and popping it off. **This perturbs
/// the position of what used to be the last element!**
///
/// Return `None` if `value` was not in the set.
///
/// Computes in **O(1)** time (average).
pub fn swap_take<Q>(&mut self, value: &Q) -> Option<T>
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.map.swap_remove_entry(value).map(|(x, ())| x)
}
/// Removes and returns the value in the set, if any, that is equal to the
/// given one.
///
/// Like [`Vec::remove`], the value is removed by shifting all of the
/// elements that follow it, preserving their relative order.
/// **This perturbs the index of all of those elements!**
///
/// Return `None` if `value` was not in the set.
///
/// Computes in **O(n)** time (average).
pub fn shift_take<Q>(&mut self, value: &Q) -> Option<T>
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.map.shift_remove_entry(value).map(|(x, ())| x)
}
/// Remove the value from the set return it and the index it had.
///
/// Like [`Vec::swap_remove`], the value is removed by swapping it with the
/// last element of the set and popping it off. **This perturbs
/// the position of what used to be the last element!**
///
/// Return `None` if `value` was not in the set.
pub fn swap_remove_full<Q>(&mut self, value: &Q) -> Option<(usize, T)>
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.map.swap_remove_full(value).map(|(i, x, ())| (i, x))
}
/// Remove the value from the set return it and the index it had.
///
/// Like [`Vec::remove`], the value is removed by shifting all of the
/// elements that follow it, preserving their relative order.
/// **This perturbs the index of all of those elements!**
///
/// Return `None` if `value` was not in the set.
pub fn shift_remove_full<Q>(&mut self, value: &Q) -> Option<(usize, T)>
where
Q: ?Sized + Hash + Equivalent<T>,
{
self.map.shift_remove_full(value).map(|(i, x, ())| (i, x))
}
}
impl<T, S> IndexSet<T, S> {
/// Remove the last value
///
/// This preserves the order of the remaining elements.
///
/// Computes in **O(1)** time (average).
pub fn pop(&mut self) -> Option<T> {
self.map.pop().map(|(x, ())| x)
}
/// Scan through each value in the set and keep those where the
/// closure `keep` returns `true`.
///
/// The elements are visited in order, and remaining elements keep their
/// order.
///
/// Computes in **O(n)** time (average).
pub fn retain<F>(&mut self, mut keep: F)
where
F: FnMut(&T) -> bool,
{
self.map.retain(move |x, &mut ()| keep(x))
}
/// Sort the set’s values by their default ordering.
///
/// This is a stable sort -- but equivalent values should not normally coexist in
/// a set at all, so [`sort_unstable`][Self::sort_unstable] is preferred
/// because it is generally faster and doesn't allocate auxiliary memory.
///
/// See [`sort_by`](Self::sort_by) for details.
pub fn sort(&mut self)
where
T: Ord,
{
self.map.sort_keys()
}
/// Sort the set’s values in place using the comparison function `cmp`.
///
/// Computes in **O(n log n)** time and **O(n)** space. The sort is stable.
pub fn sort_by<F>(&mut self, mut cmp: F)
where
F: FnMut(&T, &T) -> Ordering,
{
self.map.sort_by(move |a, _, b, _| cmp(a, b));
}
/// Sort the values of the set and return a by-value iterator of
/// the values with the result.
///
/// The sort is stable.
pub fn sorted_by<F>(self, mut cmp: F) -> IntoIter<T>
where
F: FnMut(&T, &T) -> Ordering,
{
let mut entries = self.into_entries();
entries.sort_by(move |a, b| cmp(&a.key, &b.key));
IntoIter::new(entries)
}
/// Sort the set's values by their default ordering.
///
/// See [`sort_unstable_by`](Self::sort_unstable_by) for details.
pub fn sort_unstable(&mut self)
where
T: Ord,
{
self.map.sort_unstable_keys()
}
/// Sort the set's values in place using the comparison function `cmp`.
///
/// Computes in **O(n log n)** time. The sort is unstable.
pub fn sort_unstable_by<F>(&mut self, mut cmp: F)
where
F: FnMut(&T, &T) -> Ordering,
{
self.map.sort_unstable_by(move |a, _, b, _| cmp(a, b))
}
/// Sort the values of the set and return a by-value iterator of
/// the values with the result.
pub fn sorted_unstable_by<F>(self, mut cmp: F) -> IntoIter<T>
where
F: FnMut(&T, &T) -> Ordering,
{
let mut entries = self.into_entries();
entries.sort_unstable_by(move |a, b| cmp(&a.key, &b.key));
IntoIter::new(entries)
}
/// Sort the set’s values in place using a key extraction function.
///
/// During sorting, the function is called at most once per entry, by using temporary storage
/// to remember the results of its evaluation. The order of calls to the function is
/// unspecified and may change between versions of `indexmap` or the standard library.
///
/// Computes in **O(m n + n log n + c)** time () and **O(n)** space, where the function is
/// **O(m)**, *n* is the length of the map, and *c* the capacity. The sort is stable.
pub fn sort_by_cached_key<K, F>(&mut self, mut sort_key: F)
where
K: Ord,
F: FnMut(&T) -> K,
{
self.with_entries(move |entries| {
entries.sort_by_cached_key(move |a| sort_key(&a.key));
});
}
/// Search over a sorted set for a value.
///
/// Returns the position where that value is present, or the position where it can be inserted
/// to maintain the sort. See [`slice::binary_search`] for more details.
///
/// Computes in **O(log(n))** time, which is notably less scalable than looking the value up
/// using [`get_index_of`][IndexSet::get_index_of], but this can also position missing values.
pub fn binary_search(&self, x: &T) -> Result<usize, usize>
where
T: Ord,
{
self.as_slice().binary_search(x)
}
/// Search over a sorted set with a comparator function.
///
/// Returns the position where that value is present, or the position where it can be inserted
/// to maintain the sort. See [`slice::binary_search_by`] for more details.
///
/// Computes in **O(log(n))** time.
#[inline]
pub fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize>
where
F: FnMut(&'a T) -> Ordering,
{
self.as_slice().binary_search_by(f)
}
/// Search over a sorted set with an extraction function.
///
/// Returns the position where that value is present, or the position where it can be inserted
/// to maintain the sort. See [`slice::binary_search_by_key`] for more details.
///
/// Computes in **O(log(n))** time.
#[inline]
pub fn binary_search_by_key<'a, B, F>(&'a self, b: &B, f: F) -> Result<usize, usize>
where
F: FnMut(&'a T) -> B,
B: Ord,
{
self.as_slice().binary_search_by_key(b, f)
}
/// Returns the index of the partition point of a sorted set according to the given predicate
/// (the index of the first element of the second partition).
///
/// See [`slice::partition_point`] for more details.
///
/// Computes in **O(log(n))** time.
#[must_use]
pub fn partition_point<P>(&self, pred: P) -> usize
where
P: FnMut(&T) -> bool,
{
self.as_slice().partition_point(pred)
}
/// Reverses the order of the set’s values in place.
///
/// Computes in **O(n)** time and **O(1)** space.
pub fn reverse(&mut self) {
self.map.reverse()
}
/// Returns a slice of all the values in the set.
///
/// Computes in **O(1)** time.
pub fn as_slice(&self) -> &Slice<T> {
Slice::from_slice(self.as_entries())
}
/// Converts into a boxed slice of all the values in the set.
///
/// Note that this will drop the inner hash table and any excess capacity.
pub fn into_boxed_slice(self) -> Box<Slice<T>> {
Slice::from_boxed(self.into_entries().into_boxed_slice())
}
/// Get a value by index
///
/// Valid indices are *0 <= index < self.len()*
///
/// Computes in **O(1)** time.
pub fn get_index(&self, index: usize) -> Option<&T> {
self.as_entries().get(index).map(Bucket::key_ref)
}
/// Returns a slice of values in the given range of indices.
///
/// Valid indices are *0 <= index < self.len()*
///
/// Computes in **O(1)** time.
pub fn get_range<R: RangeBounds<usize>>(&self, range: R) -> Option<&Slice<T>> {
let entries = self.as_entries();
let range = try_simplify_range(range, entries.len())?;
entries.get(range).map(Slice::from_slice)
}
/// Get the first value
///
/// Computes in **O(1)** time.
pub fn first(&self) -> Option<&T> {
self.as_entries().first().map(Bucket::key_ref)
}
/// Get the last value
///
/// Computes in **O(1)** time.
pub fn last(&self) -> Option<&T> {
self.as_entries().last().map(Bucket::key_ref)
}
/// Remove the value by index
///
/// Valid indices are *0 <= index < self.len()*
///
/// Like [`Vec::swap_remove`], the value is removed by swapping it with the
/// last element of the set and popping it off. **This perturbs
/// the position of what used to be the last element!**
///
/// Computes in **O(1)** time (average).
pub fn swap_remove_index(&mut self, index: usize) -> Option<T> {
self.map.swap_remove_index(index).map(|(x, ())| x)
}
/// Remove the value by index
///
/// Valid indices are *0 <= index < self.len()*
///
/// Like [`Vec::remove`], the value is removed by shifting all of the
/// elements that follow it, preserving their relative order.
/// **This perturbs the index of all of those elements!**
///
/// Computes in **O(n)** time (average).
pub fn shift_remove_index(&mut self, index: usize) -> Option<T> {
self.map.shift_remove_index(index).map(|(x, ())| x)
}
/// Moves the position of a value from one index to another
/// by shifting all other values in-between.
///
/// * If `from < to`, the other values will shift down while the targeted value moves up.
/// * If `from > to`, the other values will shift up while the targeted value moves down.
///
/// ***Panics*** if `from` or `to` are out of bounds.
///
/// Computes in **O(n)** time (average).
pub fn move_index(&mut self, from: usize, to: usize) {
self.map.move_index(from, to)
}
/// Swaps the position of two values in the set.
///
/// ***Panics*** if `a` or `b` are out of bounds.
///
/// Computes in **O(1)** time (average).
pub fn swap_indices(&mut self, a: usize, b: usize) {
self.map.swap_indices(a, b)
}
}
/// Access [`IndexSet`] values at indexed positions.
///
/// # Examples
///
/// ```
/// use indexmap::IndexSet;
///
/// let mut set = IndexSet::new();
/// for word in "Lorem ipsum dolor sit amet".split_whitespace() {
/// set.insert(word.to_string());
/// }
/// assert_eq!(set[0], "Lorem");
/// assert_eq!(set[1], "ipsum");
/// set.reverse();
/// assert_eq!(set[0], "amet");
/// assert_eq!(set[1], "sit");
/// set.sort();
/// assert_eq!(set[0], "Lorem");
/// assert_eq!(set[1], "amet");
/// ```
///
/// ```should_panic
/// use indexmap::IndexSet;
///
/// let mut set = IndexSet::new();
/// set.insert("foo");
/// println!("{:?}", set[10]); // panics!
/// ```
impl<T, S> Index<usize> for IndexSet<T, S> {
type Output = T;
/// Returns a reference to the value at the supplied `index`.
///
/// ***Panics*** if `index` is out of bounds.
fn index(&self, index: usize) -> &T {
self.get_index(index)
.expect("IndexSet: index out of bounds")
}
}
impl<T, S> FromIterator<T> for IndexSet<T, S>
where
T: Hash + Eq,
S: BuildHasher + Default,
{
fn from_iter<I: IntoIterator<Item = T>>(iterable: I) -> Self {
let iter = iterable.into_iter().map(|x| (x, ()));
IndexSet {
map: IndexMap::from_iter(iter),
}
}
}
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
impl<T, const N: usize> From<[T; N]> for IndexSet<T, RandomState>
where
T: Eq + Hash,
{
/// # Examples
///
/// ```
/// use indexmap::IndexSet;
///
/// let set1 = IndexSet::from([1, 2, 3, 4]);
/// let set2: IndexSet<_> = [1, 2, 3, 4].into();
/// assert_eq!(set1, set2);
/// ```
fn from(arr: [T; N]) -> Self {
Self::from_iter(arr)
}
}
impl<T, S> Extend<T> for IndexSet<T, S>
where
T: Hash + Eq,
S: BuildHasher,
{
fn extend<I: IntoIterator<Item = T>>(&mut self, iterable: I) {
let iter = iterable.into_iter().map(|x| (x, ()));
self.map.extend(iter);
}
}
impl<'a, T, S> Extend<&'a T> for IndexSet<T, S>
where
T: Hash + Eq + Copy + 'a,
S: BuildHasher,
{
fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iterable: I) {
let iter = iterable.into_iter().copied();
self.extend(iter);
}
}
impl<T, S> Default for IndexSet<T, S>
where
S: Default,
{
/// Return an empty [`IndexSet`]
fn default() -> Self {
IndexSet {
map: IndexMap::default(),
}
}
}
impl<T, S1, S2> PartialEq<IndexSet<T, S2>> for IndexSet<T, S1>
where
T: Hash + Eq,
S1: BuildHasher,
S2: BuildHasher,
{
fn eq(&self, other: &IndexSet<T, S2>) -> bool {
self.len() == other.len() && self.is_subset(other)
}
}
impl<T, S> Eq for IndexSet<T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
}
impl<T, S> IndexSet<T, S>
where
T: Eq + Hash,
S: BuildHasher,
{
/// Returns `true` if `self` has no elements in common with `other`.
pub fn is_disjoint<S2>(&self, other: &IndexSet<T, S2>) -> bool
where
S2: BuildHasher,
{
if self.len() <= other.len() {
self.iter().all(move |value| !other.contains(value))
} else {
other.iter().all(move |value| !self.contains(value))
}
}
/// Returns `true` if all elements of `self` are contained in `other`.
pub fn is_subset<S2>(&self, other: &IndexSet<T, S2>) -> bool
where
S2: BuildHasher,
{
self.len() <= other.len() && self.iter().all(move |value| other.contains(value))
}
/// Returns `true` if all elements of `other` are contained in `self`.
pub fn is_superset<S2>(&self, other: &IndexSet<T, S2>) -> bool
where
S2: BuildHasher,
{
other.is_subset(self)
}
}
impl<T, S1, S2> BitAnd<&IndexSet<T, S2>> for &IndexSet<T, S1>
where
T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
{
type Output = IndexSet<T, S1>;
/// Returns the set intersection, cloned into a new set.
///
/// Values are collected in the same order that they appear in `self`.
fn bitand(self, other: &IndexSet<T, S2>) -> Self::Output {
self.intersection(other).cloned().collect()
}
}
impl<T, S1, S2> BitOr<&IndexSet<T, S2>> for &IndexSet<T, S1>
where
T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
{
type Output = IndexSet<T, S1>;
/// Returns the set union, cloned into a new set.
///
/// Values from `self` are collected in their original order, followed by
/// values that are unique to `other` in their original order.
fn bitor(self, other: &IndexSet<T, S2>) -> Self::Output {
self.union(other).cloned().collect()
}
}
impl<T, S1, S2> BitXor<&IndexSet<T, S2>> for &IndexSet<T, S1>
where
T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
{
type Output = IndexSet<T, S1>;
/// Returns the set symmetric-difference, cloned into a new set.
///
/// Values from `self` are collected in their original order, followed by
/// values from `other` in their original order.
fn bitxor(self, other: &IndexSet<T, S2>) -> Self::Output {
self.symmetric_difference(other).cloned().collect()
}
}
impl<T, S1, S2> Sub<&IndexSet<T, S2>> for &IndexSet<T, S1>
where
T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
{
type Output = IndexSet<T, S1>;
/// Returns the set difference, cloned into a new set.
///
/// Values are collected in the same order that they appear in `self`.
fn sub(self, other: &IndexSet<T, S2>) -> Self::Output {
self.difference(other).cloned().collect()
}
}