1 files changed, 159 insertions, 0 deletions
diff --git a/src/iter/zip.rs b/src/iter/zip.rs
new file mode 100644
index 0000000..33823db
--- /dev/null
+++ b/src/iter/zip.rs
@@ -0,0 +1,159 @@
+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,
+            },
+        )
+    }
+}