rayon/iter/
zip.rs

1use super::plumbing::*;
2use super::*;
3use std::cmp;
4use std::iter;
5
6/// `Zip` is an iterator that zips up `a` and `b` into a single iterator
7/// of pairs. This struct is created by the [`zip()`] method on
8/// [`IndexedParallelIterator`]
9///
10/// [`zip()`]: trait.IndexedParallelIterator.html#method.zip
11/// [`IndexedParallelIterator`]: trait.IndexedParallelIterator.html
12#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
13#[derive(Debug, Clone)]
14pub struct Zip<A: IndexedParallelIterator, B: IndexedParallelIterator> {
15    a: A,
16    b: B,
17}
18
19impl<A, B> Zip<A, B>
20where
21    A: IndexedParallelIterator,
22    B: IndexedParallelIterator,
23{
24    /// Creates a new `Zip` iterator.
25    pub(super) fn new(a: A, b: B) -> Self {
26        Zip { a, b }
27    }
28}
29
30impl<A, B> ParallelIterator for Zip<A, B>
31where
32    A: IndexedParallelIterator,
33    B: IndexedParallelIterator,
34{
35    type Item = (A::Item, B::Item);
36
37    fn drive_unindexed<C>(self, consumer: C) -> C::Result
38    where
39        C: UnindexedConsumer<Self::Item>,
40    {
41        bridge(self, consumer)
42    }
43
44    fn opt_len(&self) -> Option<usize> {
45        Some(self.len())
46    }
47}
48
49impl<A, B> IndexedParallelIterator for Zip<A, B>
50where
51    A: IndexedParallelIterator,
52    B: IndexedParallelIterator,
53{
54    fn drive<C>(self, consumer: C) -> C::Result
55    where
56        C: Consumer<Self::Item>,
57    {
58        bridge(self, consumer)
59    }
60
61    fn len(&self) -> usize {
62        cmp::min(self.a.len(), self.b.len())
63    }
64
65    fn with_producer<CB>(self, callback: CB) -> CB::Output
66    where
67        CB: ProducerCallback<Self::Item>,
68    {
69        return self.a.with_producer(CallbackA {
70            callback,
71            b: self.b,
72        });
73
74        struct CallbackA<CB, B> {
75            callback: CB,
76            b: B,
77        }
78
79        impl<CB, ITEM, B> ProducerCallback<ITEM> for CallbackA<CB, B>
80        where
81            B: IndexedParallelIterator,
82            CB: ProducerCallback<(ITEM, B::Item)>,
83        {
84            type Output = CB::Output;
85
86            fn callback<A>(self, a_producer: A) -> Self::Output
87            where
88                A: Producer<Item = ITEM>,
89            {
90                self.b.with_producer(CallbackB {
91                    a_producer,
92                    callback: self.callback,
93                })
94            }
95        }
96
97        struct CallbackB<CB, A> {
98            a_producer: A,
99            callback: CB,
100        }
101
102        impl<CB, A, ITEM> ProducerCallback<ITEM> for CallbackB<CB, A>
103        where
104            A: Producer,
105            CB: ProducerCallback<(A::Item, ITEM)>,
106        {
107            type Output = CB::Output;
108
109            fn callback<B>(self, b_producer: B) -> Self::Output
110            where
111                B: Producer<Item = ITEM>,
112            {
113                self.callback.callback(ZipProducer {
114                    a: self.a_producer,
115                    b: b_producer,
116                })
117            }
118        }
119    }
120}
121
122/// ////////////////////////////////////////////////////////////////////////
123
124struct ZipProducer<A: Producer, B: Producer> {
125    a: A,
126    b: B,
127}
128
129impl<A: Producer, B: Producer> Producer for ZipProducer<A, B> {
130    type Item = (A::Item, B::Item);
131    type IntoIter = iter::Zip<A::IntoIter, B::IntoIter>;
132
133    fn into_iter(self) -> Self::IntoIter {
134        self.a.into_iter().zip(self.b.into_iter())
135    }
136
137    fn min_len(&self) -> usize {
138        cmp::max(self.a.min_len(), self.b.min_len())
139    }
140
141    fn max_len(&self) -> usize {
142        cmp::min(self.a.max_len(), self.b.max_len())
143    }
144
145    fn split_at(self, index: usize) -> (Self, Self) {
146        let (a_left, a_right) = self.a.split_at(index);
147        let (b_left, b_right) = self.b.split_at(index);
148        (
149            ZipProducer {
150                a: a_left,
151                b: b_left,
152            },
153            ZipProducer {
154                a: a_right,
155                b: b_right,
156            },
157        )
158    }
159}
rayon/iter/zip.rs

rayon/iter/
zip.rs
