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use super::plumbing::*;
use super::*;
use std::cmp;
use std::iter;
/// `Zip` is an iterator that zips up `a` and `b` into a single iterator
/// of pairs. This struct is created by the [`zip()`] method on
/// [`IndexedParallelIterator`]
///
/// [`zip()`]: trait.IndexedParallelIterator.html#method.zip
/// [`IndexedParallelIterator`]: trait.IndexedParallelIterator.html
#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
#[derive(Debug, Clone)]
pub struct Zip<A: IndexedParallelIterator, B: IndexedParallelIterator> {
a: A,
b: B,
}
impl<A, B> Zip<A, B>
where
A: IndexedParallelIterator,
B: IndexedParallelIterator,
{
/// Creates a new `Zip` iterator.
pub(super) fn new(a: A, b: B) -> Self {
Zip { a, b }
}
}
impl<A, B> ParallelIterator for Zip<A, B>
where
A: IndexedParallelIterator,
B: IndexedParallelIterator,
{
type Item = (A::Item, B::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<A, B> IndexedParallelIterator for Zip<A, B>
where
A: IndexedParallelIterator,
B: IndexedParallelIterator,
{
fn drive<C>(self, consumer: C) -> C::Result
where
C: Consumer<Self::Item>,
{
bridge(self, consumer)
}
fn len(&self) -> usize {
cmp::min(self.a.len(), self.b.len())
}
fn with_producer<CB>(self, callback: CB) -> CB::Output
where
CB: ProducerCallback<Self::Item>,
{
return self.a.with_producer(CallbackA {
callback,
b: self.b,
});
struct CallbackA<CB, B> {
callback: CB,
b: B,
}
impl<CB, ITEM, B> ProducerCallback<ITEM> for CallbackA<CB, B>
where
B: IndexedParallelIterator,
CB: ProducerCallback<(ITEM, B::Item)>,
{
type Output = CB::Output;
fn callback<A>(self, a_producer: A) -> Self::Output
where
A: Producer<Item = ITEM>,
{
self.b.with_producer(CallbackB {
a_producer,
callback: self.callback,
})
}
}
struct CallbackB<CB, A> {
a_producer: A,
callback: CB,
}
impl<CB, A, ITEM> ProducerCallback<ITEM> for CallbackB<CB, A>
where
A: Producer,
CB: ProducerCallback<(A::Item, ITEM)>,
{
type Output = CB::Output;
fn callback<B>(self, b_producer: B) -> Self::Output
where
B: Producer<Item = ITEM>,
{
self.callback.callback(ZipProducer {
a: self.a_producer,
b: b_producer,
})
}
}
}
}
/// ////////////////////////////////////////////////////////////////////////
struct ZipProducer<A: Producer, B: Producer> {
a: A,
b: B,
}
impl<A: Producer, B: Producer> Producer for ZipProducer<A, B> {
type Item = (A::Item, B::Item);
type IntoIter = iter::Zip<A::IntoIter, B::IntoIter>;
fn into_iter(self) -> Self::IntoIter {
self.a.into_iter().zip(self.b.into_iter())
}
fn min_len(&self) -> usize {
cmp::max(self.a.min_len(), self.b.min_len())
}
fn max_len(&self) -> usize {
cmp::min(self.a.max_len(), self.b.max_len())
}
fn split_at(self, index: usize) -> (Self, Self) {
let (a_left, a_right) = self.a.split_at(index);
let (b_left, b_right) = self.b.split_at(index);
(
ZipProducer {
a: a_left,
b: b_left,
},
ZipProducer {
a: a_right,
b: b_right,
},
)
}
}