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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /vendor/rayon/src/iter/step_by.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'vendor/rayon/src/iter/step_by.rs')
-rw-r--r-- | vendor/rayon/src/iter/step_by.rs | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/vendor/rayon/src/iter/step_by.rs b/vendor/rayon/src/iter/step_by.rs new file mode 100644 index 000000000..863de3cf0 --- /dev/null +++ b/vendor/rayon/src/iter/step_by.rs @@ -0,0 +1,144 @@ +#![cfg(has_step_by_rev)] +use std::cmp::min; + +use super::plumbing::*; +use super::*; +use crate::math::div_round_up; +use std::iter; +use std::usize; + +/// `StepBy` is an iterator that skips `n` elements between each yield, where `n` is the given step. +/// This struct is created by the [`step_by()`] method on [`IndexedParallelIterator`] +/// +/// [`step_by()`]: trait.IndexedParallelIterator.html#method.step_by +/// [`IndexedParallelIterator`]: trait.IndexedParallelIterator.html +#[must_use = "iterator adaptors are lazy and do nothing unless consumed"] +#[derive(Debug, Clone)] +pub struct StepBy<I: IndexedParallelIterator> { + base: I, + step: usize, +} + +impl<I> StepBy<I> +where + I: IndexedParallelIterator, +{ + /// Creates a new `StepBy` iterator. + pub(super) fn new(base: I, step: usize) -> Self { + StepBy { base, step } + } +} + +impl<I> ParallelIterator for StepBy<I> +where + I: IndexedParallelIterator, +{ + type Item = I::Item; + + fn drive_unindexed<C>(self, consumer: C) -> C::Result + where + C: UnindexedConsumer<Self::Item>, + { + bridge(self, consumer) + } + + fn opt_len(&self) -> Option<usize> { + Some(self.len()) + } +} + +impl<I> IndexedParallelIterator for StepBy<I> +where + I: IndexedParallelIterator, +{ + fn drive<C: Consumer<Self::Item>>(self, consumer: C) -> C::Result { + bridge(self, consumer) + } + + fn len(&self) -> usize { + div_round_up(self.base.len(), self.step) + } + + fn with_producer<CB>(self, callback: CB) -> CB::Output + where + CB: ProducerCallback<Self::Item>, + { + let len = self.base.len(); + return self.base.with_producer(Callback { + callback, + step: self.step, + len, + }); + + struct Callback<CB> { + callback: CB, + step: usize, + len: usize, + } + + impl<T, CB> ProducerCallback<T> for Callback<CB> + where + CB: ProducerCallback<T>, + { + type Output = CB::Output; + fn callback<P>(self, base: P) -> CB::Output + where + P: Producer<Item = T>, + { + let producer = StepByProducer { + base, + step: self.step, + len: self.len, + }; + self.callback.callback(producer) + } + } + } +} + +/// //////////////////////////////////////////////////////////////////////// +/// Producer implementation + +struct StepByProducer<P> { + base: P, + step: usize, + len: usize, +} + +impl<P> Producer for StepByProducer<P> +where + P: Producer, +{ + type Item = P::Item; + type IntoIter = iter::StepBy<P::IntoIter>; + + fn into_iter(self) -> Self::IntoIter { + self.base.into_iter().step_by(self.step) + } + + fn split_at(self, index: usize) -> (Self, Self) { + let elem_index = min(index * self.step, self.len); + + let (left, right) = self.base.split_at(elem_index); + ( + StepByProducer { + base: left, + step: self.step, + len: elem_index, + }, + StepByProducer { + base: right, + step: self.step, + len: self.len - elem_index, + }, + ) + } + + fn min_len(&self) -> usize { + div_round_up(self.base.min_len(), self.step) + } + + fn max_len(&self) -> usize { + self.base.max_len() / self.step + } +} |