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Diffstat (limited to 'src/external_trait_impls/rayon/set.rs')
| -rw-r--r-- | src/external_trait_impls/rayon/set.rs | 646 |
1 files changed, 646 insertions, 0 deletions
diff --git a/src/external_trait_impls/rayon/set.rs b/src/external_trait_impls/rayon/set.rs new file mode 100644 index 0000000..53d2660 --- /dev/null +++ b/src/external_trait_impls/rayon/set.rs @@ -0,0 +1,646 @@ +//! Rayon extensions for `HashSet`. + +use crate::hash_set::HashSet; +use core::hash::{BuildHasher, Hash}; +use rayon::iter::plumbing::UnindexedConsumer; +use rayon::iter::{FromParallelIterator, IntoParallelIterator, ParallelExtend, ParallelIterator}; + +/// Parallel iterator over elements of a consumed set. +/// +/// This iterator is created by the [`into_par_iter`] method on [`HashSet`] +/// (provided by the [`IntoParallelIterator`] trait). +/// See its documentation for more. +/// +/// [`into_par_iter`]: /hashbrown/struct.HashSet.html#method.into_par_iter +/// [`HashSet`]: /hashbrown/struct.HashSet.html +/// [`IntoParallelIterator`]: https://docs.rs/rayon/1.0/rayon/iter/trait.IntoParallelIterator.html +pub struct IntoParIter<T, S> { + set: HashSet<T, S>, +} + +impl<T: Send, S: Send> ParallelIterator for IntoParIter<T, S> { + type Item = T; + + fn drive_unindexed<C>(self, consumer: C) -> C::Result + where + C: UnindexedConsumer<Self::Item>, + { + self.set + .map + .into_par_iter() + .map(|(k, _)| k) + .drive_unindexed(consumer) + } +} + +/// Parallel draining iterator over entries of a set. +/// +/// This iterator is created by the [`par_drain`] method on [`HashSet`]. +/// See its documentation for more. +/// +/// [`par_drain`]: /hashbrown/struct.HashSet.html#method.par_drain +/// [`HashSet`]: /hashbrown/struct.HashSet.html +pub struct ParDrain<'a, T, S> { + set: &'a mut HashSet<T, S>, +} + +impl<T: Send, S: Send> ParallelIterator for ParDrain<'_, T, S> { + type Item = T; + + fn drive_unindexed<C>(self, consumer: C) -> C::Result + where + C: UnindexedConsumer<Self::Item>, + { + self.set + .map + .par_drain() + .map(|(k, _)| k) + .drive_unindexed(consumer) + } +} + +/// Parallel iterator over shared references to elements in a set. +/// +/// This iterator is created by the [`par_iter`] method on [`HashSet`] +/// (provided by the [`IntoParallelRefIterator`] trait). +/// See its documentation for more. +/// +/// [`par_iter`]: /hashbrown/struct.HashSet.html#method.par_iter +/// [`HashSet`]: /hashbrown/struct.HashSet.html +/// [`IntoParallelRefIterator`]: https://docs.rs/rayon/1.0/rayon/iter/trait.IntoParallelRefIterator.html +pub struct ParIter<'a, T, S> { + set: &'a HashSet<T, S>, +} + +impl<'a, T: Sync, S: Sync> ParallelIterator for ParIter<'a, T, S> { + type Item = &'a T; + + fn drive_unindexed<C>(self, consumer: C) -> C::Result + where + C: UnindexedConsumer<Self::Item>, + { + self.set.map.par_keys().drive_unindexed(consumer) + } +} + +/// Parallel iterator over shared references to elements in the difference of +/// sets. +/// +/// This iterator is created by the [`par_difference`] method on [`HashSet`]. +/// See its documentation for more. +/// +/// [`par_difference`]: /hashbrown/struct.HashSet.html#method.par_difference +/// [`HashSet`]: /hashbrown/struct.HashSet.html +pub struct ParDifference<'a, T, S> { + a: &'a HashSet<T, S>, + b: &'a HashSet<T, S>, +} + +impl<'a, T, S> ParallelIterator for ParDifference<'a, T, S> +where + T: Eq + Hash + Sync, + S: BuildHasher + Sync, +{ + type Item = &'a T; + + fn drive_unindexed<C>(self, consumer: C) -> C::Result + where + C: UnindexedConsumer<Self::Item>, + { + self.a + .into_par_iter() + .filter(|&x| !self.b.contains(x)) + .drive_unindexed(consumer) + } +} + +/// Parallel iterator over shared references to elements in the symmetric +/// difference of sets. +/// +/// This iterator is created by the [`par_symmetric_difference`] method on +/// [`HashSet`]. +/// See its documentation for more. +/// +/// [`par_symmetric_difference`]: /hashbrown/struct.HashSet.html#method.par_symmetric_difference +/// [`HashSet`]: /hashbrown/struct.HashSet.html +pub struct ParSymmetricDifference<'a, T, S> { + a: &'a HashSet<T, S>, + b: &'a HashSet<T, S>, +} + +impl<'a, T, S> ParallelIterator for ParSymmetricDifference<'a, T, S> +where + T: Eq + Hash + Sync, + S: BuildHasher + Sync, +{ + type Item = &'a T; + + fn drive_unindexed<C>(self, consumer: C) -> C::Result + where + C: UnindexedConsumer<Self::Item>, + { + self.a + .par_difference(self.b) + .chain(self.b.par_difference(self.a)) + .drive_unindexed(consumer) + } +} + +/// Parallel iterator over shared references to elements in the intersection of +/// sets. +/// +/// This iterator is created by the [`par_intersection`] method on [`HashSet`]. +/// See its documentation for more. +/// +/// [`par_intersection`]: /hashbrown/struct.HashSet.html#method.par_intersection +/// [`HashSet`]: /hashbrown/struct.HashSet.html +pub struct ParIntersection<'a, T, S> { + a: &'a HashSet<T, S>, + b: &'a HashSet<T, S>, +} + +impl<'a, T, S> ParallelIterator for ParIntersection<'a, T, S> +where + T: Eq + Hash + Sync, + S: BuildHasher + Sync, +{ + type Item = &'a T; + + fn drive_unindexed<C>(self, consumer: C) -> C::Result + where + C: UnindexedConsumer<Self::Item>, + { + self.a + .into_par_iter() + .filter(|&x| self.b.contains(x)) + .drive_unindexed(consumer) + } +} + +/// Parallel iterator over shared references to elements in the union of sets. +/// +/// This iterator is created by the [`par_union`] method on [`HashSet`]. +/// See its documentation for more. +/// +/// [`par_union`]: /hashbrown/struct.HashSet.html#method.par_union +/// [`HashSet`]: /hashbrown/struct.HashSet.html +pub struct ParUnion<'a, T, S> { + a: &'a HashSet<T, S>, + b: &'a HashSet<T, S>, +} + +impl<'a, T, S> ParallelIterator for ParUnion<'a, T, S> +where + T: Eq + Hash + Sync, + S: BuildHasher + Sync, +{ + type Item = &'a T; + + fn drive_unindexed<C>(self, consumer: C) -> C::Result + where + C: UnindexedConsumer<Self::Item>, + { + self.a + .into_par_iter() + .chain(self.b.par_difference(self.a)) + .drive_unindexed(consumer) + } +} + +impl<T, S> HashSet<T, S> +where + T: Eq + Hash + Sync, + S: BuildHasher + Sync, +{ + /// Visits (potentially in parallel) the values representing the difference, + /// i.e. the values that are in `self` but not in `other`. + #[cfg_attr(feature = "inline-more", inline)] + pub fn par_difference<'a>(&'a self, other: &'a Self) -> ParDifference<'a, T, S> { + ParDifference { a: self, b: other } + } + + /// Visits (potentially in parallel) the values representing the symmetric + /// difference, i.e. the values that are in `self` or in `other` but not in both. + #[cfg_attr(feature = "inline-more", inline)] + pub fn par_symmetric_difference<'a>( + &'a self, + other: &'a Self, + ) -> ParSymmetricDifference<'a, T, S> { + ParSymmetricDifference { a: self, b: other } + } + + /// Visits (potentially in parallel) the values representing the + /// intersection, i.e. the values that are both in `self` and `other`. + #[cfg_attr(feature = "inline-more", inline)] + pub fn par_intersection<'a>(&'a self, other: &'a Self) -> ParIntersection<'a, T, S> { + ParIntersection { a: self, b: other } + } + + /// Visits (potentially in parallel) the values representing the union, + /// i.e. all the values in `self` or `other`, without duplicates. + #[cfg_attr(feature = "inline-more", inline)] + pub fn par_union<'a>(&'a self, other: &'a Self) -> ParUnion<'a, T, S> { + ParUnion { a: self, b: other } + } + + /// Returns `true` if `self` has no elements in common with `other`. + /// This is equivalent to checking for an empty intersection. + /// + /// This method runs in a potentially parallel fashion. + pub fn par_is_disjoint(&self, other: &Self) -> bool { + self.into_par_iter().all(|x| !other.contains(x)) + } + + /// Returns `true` if the set is a subset of another, + /// i.e. `other` contains at least all the values in `self`. + /// + /// This method runs in a potentially parallel fashion. + pub fn par_is_subset(&self, other: &Self) -> bool { + if self.len() <= other.len() { + self.into_par_iter().all(|x| other.contains(x)) + } else { + false + } + } + + /// Returns `true` if the set is a superset of another, + /// i.e. `self` contains at least all the values in `other`. + /// + /// This method runs in a potentially parallel fashion. + pub fn par_is_superset(&self, other: &Self) -> bool { + other.par_is_subset(self) + } + + /// Returns `true` if the set is equal to another, + /// i.e. both sets contain the same values. + /// + /// This method runs in a potentially parallel fashion. + pub fn par_eq(&self, other: &Self) -> bool { + self.len() == other.len() && self.par_is_subset(other) + } +} + +impl<T, S> HashSet<T, S> +where + T: Eq + Hash + Send, + S: BuildHasher + Send, +{ + /// Consumes (potentially in parallel) all values in an arbitrary order, + /// while preserving the set's allocated memory for reuse. + #[cfg_attr(feature = "inline-more", inline)] + pub fn par_drain(&mut self) -> ParDrain<'_, T, S> { + ParDrain { set: self } + } +} + +impl<T: Send, S: Send> IntoParallelIterator for HashSet<T, S> { + type Item = T; + type Iter = IntoParIter<T, S>; + + #[cfg_attr(feature = "inline-more", inline)] + fn into_par_iter(self) -> Self::Iter { + IntoParIter { set: self } + } +} + +impl<'a, T: Sync, S: Sync> IntoParallelIterator for &'a HashSet<T, S> { + type Item = &'a T; + type Iter = ParIter<'a, T, S>; + + #[cfg_attr(feature = "inline-more", inline)] + fn into_par_iter(self) -> Self::Iter { + ParIter { set: self } + } +} + +/// Collect values from a parallel iterator into a hashset. +impl<T, S> FromParallelIterator<T> for HashSet<T, S> +where + T: Eq + Hash + Send, + S: BuildHasher + Default, +{ + fn from_par_iter<P>(par_iter: P) -> Self + where + P: IntoParallelIterator<Item = T>, + { + let mut set = HashSet::default(); + set.par_extend(par_iter); + set + } +} + +/// Extend a hash set with items from a parallel iterator. +impl<T, S> ParallelExtend<T> for HashSet<T, S> +where + T: Eq + Hash + Send, + S: BuildHasher, +{ + fn par_extend<I>(&mut self, par_iter: I) + where + I: IntoParallelIterator<Item = T>, + { + extend(self, par_iter); + } +} + +/// Extend a hash set with copied items from a parallel iterator. +impl<'a, T, S> ParallelExtend<&'a T> for HashSet<T, S> +where + T: 'a + Copy + Eq + Hash + Sync, + S: BuildHasher, +{ + fn par_extend<I>(&mut self, par_iter: I) + where + I: IntoParallelIterator<Item = &'a T>, + { + extend(self, par_iter); + } +} + +// This is equal to the normal `HashSet` -- no custom advantage. +fn extend<T, S, I>(set: &mut HashSet<T, S>, par_iter: I) +where + T: Eq + Hash, + S: BuildHasher, + I: IntoParallelIterator, + HashSet<T, S>: Extend<I::Item>, +{ + let (list, len) = super::helpers::collect(par_iter); + + // Values may be already present or show multiple times in the iterator. + // Reserve the entire length if the set is empty. + // Otherwise reserve half the length (rounded up), so the set + // will only resize twice in the worst case. + let reserve = if set.is_empty() { len } else { (len + 1) / 2 }; + set.reserve(reserve); + for vec in list { + set.extend(vec); + } +} + +#[cfg(test)] +mod test_par_set { + use alloc::vec::Vec; + use core::sync::atomic::{AtomicUsize, Ordering}; + + use rayon::prelude::*; + + use crate::hash_set::HashSet; + + #[test] + fn test_disjoint() { + let mut xs = HashSet::new(); + let mut ys = HashSet::new(); + assert!(xs.par_is_disjoint(&ys)); + assert!(ys.par_is_disjoint(&xs)); + assert!(xs.insert(5)); + assert!(ys.insert(11)); + assert!(xs.par_is_disjoint(&ys)); + assert!(ys.par_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.par_is_disjoint(&ys)); + assert!(ys.par_is_disjoint(&xs)); + assert!(ys.insert(7)); + assert!(!xs.par_is_disjoint(&ys)); + assert!(!ys.par_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.par_is_subset(&b)); + assert!(!a.par_is_superset(&b)); + assert!(!b.par_is_subset(&a)); + assert!(!b.par_is_superset(&a)); + + assert!(b.insert(5)); + + assert!(a.par_is_subset(&b)); + assert!(!a.par_is_superset(&b)); + assert!(!b.par_is_subset(&a)); + assert!(b.par_is_superset(&a)); + } + + #[test] + fn test_iterate() { + let mut a = HashSet::new(); + for i in 0..32 { + assert!(a.insert(i)); + } + let observed = AtomicUsize::new(0); + a.par_iter().for_each(|k| { + observed.fetch_or(1 << *k, Ordering::Relaxed); + }); + assert_eq!(observed.into_inner(), 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 expected = [3, 5, 11, 77]; + let i = a + .par_intersection(&b) + .map(|x| { + assert!(expected.contains(x)); + 1 + }) + .sum::<usize>(); + 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 expected = [1, 5, 11]; + let i = a + .par_difference(&b) + .map(|x| { + assert!(expected.contains(x)); + 1 + }) + .sum::<usize>(); + 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 expected = [-2, 1, 5, 11, 14, 22]; + let i = a + .par_symmetric_difference(&b) + .map(|x| { + assert!(expected.contains(x)); + 1 + }) + .sum::<usize>(); + 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 expected = [-2, 1, 3, 5, 9, 11, 13, 16, 19, 24]; + let i = a + .par_union(&b) + .map(|x| { + assert!(expected.contains(x)); + 1 + }) + .sum::<usize>(); + assert_eq!(i, expected.len()); + } + + #[test] + fn test_from_iter() { + let xs = [1, 2, 3, 4, 5, 6, 7, 8, 9]; + + let set: HashSet<_> = xs.par_iter().cloned().collect(); + + for x in &xs { + assert!(set.contains(x)); + } + } + + #[test] + fn test_move_iter() { + let hs = { + let mut hs = HashSet::new(); + + hs.insert('a'); + hs.insert('b'); + + hs + }; + + let v = hs.into_par_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.par_eq(&s2)); + + s2.insert(3); + + assert!(s1.par_eq(&s2)); + } + + #[test] + fn test_extend_ref() { + let mut a = HashSet::new(); + a.insert(1); + + a.par_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.par_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)); + } +} |