| 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() |
| } |
| } |