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}
160