160 lines
3.9 KiB
Rust
160 lines
3.9 KiB
Rust
//! This module contains the parallel iterator types for double-ended queues
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//! (`VecDeque<T>`). You will rarely need to interact with it directly
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//! unless you have need to name one of the iterator types.
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use std::collections::VecDeque;
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use std::ops::{Range, RangeBounds};
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use crate::iter::plumbing::*;
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use crate::iter::*;
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use crate::math::simplify_range;
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use crate::slice;
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use crate::vec;
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/// Parallel iterator over a double-ended queue
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#[derive(Debug, Clone)]
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pub struct IntoIter<T: Send> {
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inner: vec::IntoIter<T>,
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}
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impl<T: Send> IntoParallelIterator for VecDeque<T> {
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type Item = T;
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type Iter = IntoIter<T>;
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fn into_par_iter(self) -> Self::Iter {
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// NOTE: requires data movement if the deque doesn't start at offset 0.
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let inner = Vec::from(self).into_par_iter();
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IntoIter { inner }
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}
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}
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delegate_indexed_iterator! {
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IntoIter<T> => T,
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impl<T: Send>
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}
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/// Parallel iterator over an immutable reference to a double-ended queue
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#[derive(Debug)]
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pub struct Iter<'a, T> {
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inner: Chain<slice::Iter<'a, T>, slice::Iter<'a, T>>,
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}
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impl<T> Clone for Iter<'_, T> {
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fn clone(&self) -> Self {
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Iter {
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inner: self.inner.clone(),
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}
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}
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}
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impl<'a, T: Sync> IntoParallelIterator for &'a VecDeque<T> {
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type Item = &'a T;
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type Iter = Iter<'a, T>;
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fn into_par_iter(self) -> Self::Iter {
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let (a, b) = self.as_slices();
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Iter {
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inner: a.into_par_iter().chain(b),
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}
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}
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}
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delegate_indexed_iterator! {
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Iter<'a, T> => &'a T,
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impl<'a, T: Sync>
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}
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/// Parallel iterator over a mutable reference to a double-ended queue
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#[derive(Debug)]
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pub struct IterMut<'a, T> {
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inner: Chain<slice::IterMut<'a, T>, slice::IterMut<'a, T>>,
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}
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impl<'a, T: Send> IntoParallelIterator for &'a mut VecDeque<T> {
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type Item = &'a mut T;
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type Iter = IterMut<'a, T>;
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fn into_par_iter(self) -> Self::Iter {
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let (a, b) = self.as_mut_slices();
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IterMut {
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inner: a.into_par_iter().chain(b),
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}
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}
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}
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delegate_indexed_iterator! {
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IterMut<'a, T> => &'a mut T,
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impl<'a, T: Send>
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}
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/// Draining parallel iterator that moves a range out of a double-ended queue,
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/// but keeps the total capacity.
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#[derive(Debug)]
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pub struct Drain<'a, T> {
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deque: &'a mut VecDeque<T>,
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range: Range<usize>,
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orig_len: usize,
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}
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impl<'a, T: Send> ParallelDrainRange<usize> for &'a mut VecDeque<T> {
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type Iter = Drain<'a, T>;
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type Item = T;
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fn par_drain<R: RangeBounds<usize>>(self, range: R) -> Self::Iter {
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Drain {
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orig_len: self.len(),
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range: simplify_range(range, self.len()),
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deque: self,
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}
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}
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}
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impl<T: Send> ParallelIterator for Drain<'_, T> {
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type Item = T;
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fn drive_unindexed<C>(self, consumer: C) -> C::Result
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where
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C: UnindexedConsumer<Self::Item>,
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{
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bridge(self, consumer)
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}
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fn opt_len(&self) -> Option<usize> {
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Some(self.len())
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}
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}
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impl<T: Send> IndexedParallelIterator for Drain<'_, T> {
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fn drive<C>(self, consumer: C) -> C::Result
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where
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C: Consumer<Self::Item>,
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{
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bridge(self, consumer)
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}
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fn len(&self) -> usize {
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self.range.len()
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}
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fn with_producer<CB>(self, callback: CB) -> CB::Output
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where
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CB: ProducerCallback<Self::Item>,
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{
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// NOTE: requires data movement if the deque doesn't start at offset 0.
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super::DrainGuard::new(self.deque)
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.par_drain(self.range.clone())
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.with_producer(callback)
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}
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}
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impl<T> Drop for Drain<'_, T> {
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fn drop(&mut self) {
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if self.deque.len() != self.orig_len - self.range.len() {
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// We must not have produced, so just call a normal drain to remove the items.
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assert_eq!(self.deque.len(), self.orig_len);
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self.deque.drain(self.range.clone());
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}
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}
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}
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