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