diff options
author | Jakub Kotur <qtr@google.com> | 2021-03-16 20:22:30 +0000 |
---|---|---|
committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | 2021-03-16 20:22:30 +0000 |
commit | 4c0b8e0ef78bcd80a4facc34c6a2158d83f96802 (patch) | |
tree | 13641ab7afc7aa43b586606c18d53084dedf7ace /src/iter/filter.rs | |
parent | a679e9b8b7e4ae27a19b81f216e375ea8a9cdb8e (diff) | |
parent | 7522a9ba008ac88224e0990932bdd298a43a2336 (diff) | |
download | rayon-4c0b8e0ef78bcd80a4facc34c6a2158d83f96802.tar.gz |
Initial import of rayon-1.5.0. am: 041839ceab am: d836dd6404 am: 7522a9ba00
Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/rayon/+/1622436
Change-Id: I94b0e06d9da131d6f98db436ad1a178dfff2ec90
Diffstat (limited to 'src/iter/filter.rs')
-rw-r--r-- | src/iter/filter.rs | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/src/iter/filter.rs b/src/iter/filter.rs new file mode 100644 index 0000000..38627f7 --- /dev/null +++ b/src/iter/filter.rs @@ -0,0 +1,141 @@ +use super::plumbing::*; +use super::*; + +use std::fmt::{self, Debug}; + +/// `Filter` takes a predicate `filter_op` and filters out elements that match. +/// This struct is created by the [`filter()`] method on [`ParallelIterator`] +/// +/// [`filter()`]: trait.ParallelIterator.html#method.filter +/// [`ParallelIterator`]: trait.ParallelIterator.html +#[must_use = "iterator adaptors are lazy and do nothing unless consumed"] +#[derive(Clone)] +pub struct Filter<I: ParallelIterator, P> { + base: I, + filter_op: P, +} + +impl<I: ParallelIterator + Debug, P> Debug for Filter<I, P> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Filter").field("base", &self.base).finish() + } +} + +impl<I, P> Filter<I, P> +where + I: ParallelIterator, +{ + /// Creates a new `Filter` iterator. + pub(super) fn new(base: I, filter_op: P) -> Self { + Filter { base, filter_op } + } +} + +impl<I, P> ParallelIterator for Filter<I, P> +where + I: ParallelIterator, + P: Fn(&I::Item) -> bool + Sync + Send, +{ + type Item = I::Item; + + fn drive_unindexed<C>(self, consumer: C) -> C::Result + where + C: UnindexedConsumer<Self::Item>, + { + let consumer1 = FilterConsumer::new(consumer, &self.filter_op); + self.base.drive_unindexed(consumer1) + } +} + +/// //////////////////////////////////////////////////////////////////////// +/// Consumer implementation + +struct FilterConsumer<'p, C, P> { + base: C, + filter_op: &'p P, +} + +impl<'p, C, P> FilterConsumer<'p, C, P> { + fn new(base: C, filter_op: &'p P) -> Self { + FilterConsumer { base, filter_op } + } +} + +impl<'p, T, C, P: 'p> Consumer<T> for FilterConsumer<'p, C, P> +where + C: Consumer<T>, + P: Fn(&T) -> bool + Sync, +{ + type Folder = FilterFolder<'p, C::Folder, P>; + type Reducer = C::Reducer; + type Result = C::Result; + + fn split_at(self, index: usize) -> (Self, Self, C::Reducer) { + let (left, right, reducer) = self.base.split_at(index); + ( + FilterConsumer::new(left, self.filter_op), + FilterConsumer::new(right, self.filter_op), + reducer, + ) + } + + fn into_folder(self) -> Self::Folder { + FilterFolder { + base: self.base.into_folder(), + filter_op: self.filter_op, + } + } + + fn full(&self) -> bool { + self.base.full() + } +} + +impl<'p, T, C, P: 'p> UnindexedConsumer<T> for FilterConsumer<'p, C, P> +where + C: UnindexedConsumer<T>, + P: Fn(&T) -> bool + Sync, +{ + fn split_off_left(&self) -> Self { + FilterConsumer::new(self.base.split_off_left(), &self.filter_op) + } + + fn to_reducer(&self) -> Self::Reducer { + self.base.to_reducer() + } +} + +struct FilterFolder<'p, C, P> { + base: C, + filter_op: &'p P, +} + +impl<'p, C, P, T> Folder<T> for FilterFolder<'p, C, P> +where + C: Folder<T>, + P: Fn(&T) -> bool + 'p, +{ + type Result = C::Result; + + fn consume(self, item: T) -> Self { + let filter_op = self.filter_op; + if filter_op(&item) { + let base = self.base.consume(item); + FilterFolder { base, filter_op } + } else { + self + } + } + + // This cannot easily specialize `consume_iter` to be better than + // the default, because that requires checking `self.base.full()` + // during a call to `self.base.consume_iter()`. (#632) + + fn complete(self) -> Self::Result { + self.base.complete() + } + + fn full(&self) -> bool { + self.base.full() + } +} |