rayon/iter/
zip.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
use super::plumbing::*;
use super::*;
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 {
        Ord::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 {
        Ord::max(self.a.min_len(), self.b.min_len())
    }

    fn max_len(&self) -> usize {
        Ord::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,
            },
        )
    }
}