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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()
}
}