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use super::plumbing::*;
use super::*;
/// `InterleaveShortest` is an iterator that works similarly to
/// `Interleave`, but this version stops returning elements once one
/// of the iterators run out.
///
/// This struct is created by the [`interleave_shortest()`] method on
/// [`IndexedParallelIterator`].
///
/// [`interleave_shortest()`]: trait.IndexedParallelIterator.html#method.interleave_shortest
/// [`IndexedParallelIterator`]: trait.IndexedParallelIterator.html
#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
#[derive(Debug, Clone)]
pub struct InterleaveShortest<I, J>
where
I: IndexedParallelIterator,
J: IndexedParallelIterator<Item = I::Item>,
{
interleave: Interleave<Take<I>, Take<J>>,
}
impl<I, J> InterleaveShortest<I, J>
where
I: IndexedParallelIterator,
J: IndexedParallelIterator<Item = I::Item>,
{
/// Creates a new `InterleaveShortest` iterator
pub(super) fn new(i: I, j: J) -> Self {
InterleaveShortest {
interleave: if i.len() <= j.len() {
// take equal lengths from both iterators
let n = i.len();
i.take(n).interleave(j.take(n))
} else {
// take one extra item from the first iterator
let n = j.len();
i.take(n + 1).interleave(j.take(n))
},
}
}
}
impl<I, J> ParallelIterator for InterleaveShortest<I, J>
where
I: IndexedParallelIterator,
J: IndexedParallelIterator<Item = I::Item>,
{
type Item = I::Item;
fn drive_unindexed<C>(self, consumer: C) -> C::Result
where
C: Consumer<I::Item>,
{
bridge(self, consumer)
}
fn opt_len(&self) -> Option<usize> {
Some(self.len())
}
}
impl<I, J> IndexedParallelIterator for InterleaveShortest<I, J>
where
I: IndexedParallelIterator,
J: IndexedParallelIterator<Item = I::Item>,
{
fn drive<C>(self, consumer: C) -> C::Result
where
C: Consumer<Self::Item>,
{
bridge(self, consumer)
}
fn len(&self) -> usize {
self.interleave.len()
}
fn with_producer<CB>(self, callback: CB) -> CB::Output
where
CB: ProducerCallback<Self::Item>,
{
self.interleave.with_producer(callback)
}
}