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Diffstat (limited to 'src/iter/map.rs')
| -rw-r--r-- | src/iter/map.rs | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/src/iter/map.rs b/src/iter/map.rs new file mode 100644 index 0000000..f2a35ff --- /dev/null +++ b/src/iter/map.rs @@ -0,0 +1,259 @@ +use super::plumbing::*; +use super::*; + +use std::fmt::{self, Debug}; +use std::iter; + +/// `Map` is an iterator that transforms the elements of an underlying iterator. +/// +/// This struct is created by the [`map()`] method on [`ParallelIterator`] +/// +/// [`map()`]: trait.ParallelIterator.html#method.map +/// [`ParallelIterator`]: trait.ParallelIterator.html +#[must_use = "iterator adaptors are lazy and do nothing unless consumed"] +#[derive(Clone)] +pub struct Map<I: ParallelIterator, F> { + base: I, + map_op: F, +} + +impl<I: ParallelIterator + Debug, F> Debug for Map<I, F> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Map").field("base", &self.base).finish() + } +} + +impl<I, F> Map<I, F> +where + I: ParallelIterator, +{ + /// Creates a new `Map` iterator. + pub(super) fn new(base: I, map_op: F) -> Self { + Map { base, map_op } + } +} + +impl<I, F, R> ParallelIterator for Map<I, F> +where + I: ParallelIterator, + F: Fn(I::Item) -> R + Sync + Send, + R: Send, +{ + type Item = F::Output; + + fn drive_unindexed<C>(self, consumer: C) -> C::Result + where + C: UnindexedConsumer<Self::Item>, + { + let consumer1 = MapConsumer::new(consumer, &self.map_op); + self.base.drive_unindexed(consumer1) + } + + fn opt_len(&self) -> Option<usize> { + self.base.opt_len() + } +} + +impl<I, F, R> IndexedParallelIterator for Map<I, F> +where + I: IndexedParallelIterator, + F: Fn(I::Item) -> R + Sync + Send, + R: Send, +{ + fn drive<C>(self, consumer: C) -> C::Result + where + C: Consumer<Self::Item>, + { + let consumer1 = MapConsumer::new(consumer, &self.map_op); + self.base.drive(consumer1) + } + + fn len(&self) -> usize { + self.base.len() + } + + fn with_producer<CB>(self, callback: CB) -> CB::Output + where + CB: ProducerCallback<Self::Item>, + { + return self.base.with_producer(Callback { + callback, + map_op: self.map_op, + }); + + struct Callback<CB, F> { + callback: CB, + map_op: F, + } + + impl<T, F, R, CB> ProducerCallback<T> for Callback<CB, F> + where + CB: ProducerCallback<R>, + F: Fn(T) -> R + Sync, + R: Send, + { + type Output = CB::Output; + + fn callback<P>(self, base: P) -> CB::Output + where + P: Producer<Item = T>, + { + let producer = MapProducer { + base, + map_op: &self.map_op, + }; + self.callback.callback(producer) + } + } + } +} + +/// //////////////////////////////////////////////////////////////////////// + +struct MapProducer<'f, P, F> { + base: P, + map_op: &'f F, +} + +impl<'f, P, F, R> Producer for MapProducer<'f, P, F> +where + P: Producer, + F: Fn(P::Item) -> R + Sync, + R: Send, +{ + type Item = F::Output; + type IntoIter = iter::Map<P::IntoIter, &'f F>; + + fn into_iter(self) -> Self::IntoIter { + self.base.into_iter().map(self.map_op) + } + + fn min_len(&self) -> usize { + self.base.min_len() + } + fn max_len(&self) -> usize { + self.base.max_len() + } + + fn split_at(self, index: usize) -> (Self, Self) { + let (left, right) = self.base.split_at(index); + ( + MapProducer { + base: left, + map_op: self.map_op, + }, + MapProducer { + base: right, + map_op: self.map_op, + }, + ) + } + + fn fold_with<G>(self, folder: G) -> G + where + G: Folder<Self::Item>, + { + let folder1 = MapFolder { + base: folder, + map_op: self.map_op, + }; + self.base.fold_with(folder1).base + } +} + +/// //////////////////////////////////////////////////////////////////////// +/// Consumer implementation + +struct MapConsumer<'f, C, F> { + base: C, + map_op: &'f F, +} + +impl<'f, C, F> MapConsumer<'f, C, F> { + fn new(base: C, map_op: &'f F) -> Self { + MapConsumer { base, map_op } + } +} + +impl<'f, T, R, C, F> Consumer<T> for MapConsumer<'f, C, F> +where + C: Consumer<F::Output>, + F: Fn(T) -> R + Sync, + R: Send, +{ + type Folder = MapFolder<'f, C::Folder, F>; + type Reducer = C::Reducer; + type Result = C::Result; + + fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) { + let (left, right, reducer) = self.base.split_at(index); + ( + MapConsumer::new(left, self.map_op), + MapConsumer::new(right, self.map_op), + reducer, + ) + } + + fn into_folder(self) -> Self::Folder { + MapFolder { + base: self.base.into_folder(), + map_op: self.map_op, + } + } + + fn full(&self) -> bool { + self.base.full() + } +} + +impl<'f, T, R, C, F> UnindexedConsumer<T> for MapConsumer<'f, C, F> +where + C: UnindexedConsumer<F::Output>, + F: Fn(T) -> R + Sync, + R: Send, +{ + fn split_off_left(&self) -> Self { + MapConsumer::new(self.base.split_off_left(), &self.map_op) + } + + fn to_reducer(&self) -> Self::Reducer { + self.base.to_reducer() + } +} + +struct MapFolder<'f, C, F> { + base: C, + map_op: &'f F, +} + +impl<'f, T, R, C, F> Folder<T> for MapFolder<'f, C, F> +where + C: Folder<F::Output>, + F: Fn(T) -> R, +{ + type Result = C::Result; + + fn consume(self, item: T) -> Self { + let mapped_item = (self.map_op)(item); + MapFolder { + base: self.base.consume(mapped_item), + map_op: self.map_op, + } + } + + fn consume_iter<I>(mut self, iter: I) -> Self + where + I: IntoIterator<Item = T>, + { + self.base = self.base.consume_iter(iter.into_iter().map(self.map_op)); + self + } + + fn complete(self) -> C::Result { + self.base.complete() + } + + fn full(&self) -> bool { + self.base.full() + } +} |