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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/rayon/src/iter/positions.rs | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/rayon/src/iter/positions.rs')
-rw-r--r-- | third_party/rust/rayon/src/iter/positions.rs | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/third_party/rust/rayon/src/iter/positions.rs b/third_party/rust/rayon/src/iter/positions.rs new file mode 100644 index 0000000000..f584bb28e2 --- /dev/null +++ b/third_party/rust/rayon/src/iter/positions.rs @@ -0,0 +1,137 @@ +use super::plumbing::*; +use super::*; + +use std::fmt::{self, Debug}; + +/// `Positions` takes a predicate `predicate` and filters out elements that match, +/// yielding their indices. +/// +/// This struct is created by the [`positions()`] method on [`IndexedParallelIterator`] +/// +/// [`positions()`]: trait.IndexedParallelIterator.html#method.positions +/// [`IndexedParallelIterator`]: trait.IndexedParallelIterator.html +#[must_use = "iterator adaptors are lazy and do nothing unless consumed"] +#[derive(Clone)] +pub struct Positions<I: IndexedParallelIterator, P> { + base: I, + predicate: P, +} + +impl<I: IndexedParallelIterator + Debug, P> Debug for Positions<I, P> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Positions") + .field("base", &self.base) + .finish() + } +} + +impl<I, P> Positions<I, P> +where + I: IndexedParallelIterator, +{ + /// Create a new `Positions` iterator. + pub(super) fn new(base: I, predicate: P) -> Self { + Positions { base, predicate } + } +} + +impl<I, P> ParallelIterator for Positions<I, P> +where + I: IndexedParallelIterator, + P: Fn(I::Item) -> bool + Sync + Send, +{ + type Item = usize; + + fn drive_unindexed<C>(self, consumer: C) -> C::Result + where + C: UnindexedConsumer<Self::Item>, + { + let consumer1 = PositionsConsumer::new(consumer, &self.predicate, 0); + self.base.drive(consumer1) + } +} + +/// //////////////////////////////////////////////////////////////////////// +/// Consumer implementation + +struct PositionsConsumer<'p, C, P> { + base: C, + predicate: &'p P, + offset: usize, +} + +impl<'p, C, P> PositionsConsumer<'p, C, P> { + fn new(base: C, predicate: &'p P, offset: usize) -> Self { + PositionsConsumer { + base, + predicate, + offset, + } + } +} + +impl<'p, T, C, P> Consumer<T> for PositionsConsumer<'p, C, P> +where + C: Consumer<usize>, + P: Fn(T) -> bool + Sync, +{ + type Folder = PositionsFolder<'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); + ( + PositionsConsumer::new(left, self.predicate, self.offset), + PositionsConsumer::new(right, self.predicate, self.offset + index), + reducer, + ) + } + + fn into_folder(self) -> Self::Folder { + PositionsFolder { + base: self.base.into_folder(), + predicate: self.predicate, + offset: self.offset, + } + } + + fn full(&self) -> bool { + self.base.full() + } +} + +struct PositionsFolder<'p, F, P> { + base: F, + predicate: &'p P, + offset: usize, +} + +impl<F, P, T> Folder<T> for PositionsFolder<'_, F, P> +where + F: Folder<usize>, + P: Fn(T) -> bool, +{ + type Result = F::Result; + + fn consume(mut self, item: T) -> Self { + let index = self.offset; + self.offset += 1; + if (self.predicate)(item) { + self.base = self.base.consume(index); + } + 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() + } +} |