rayon/iter/
sum.rs

1use super::plumbing::*;
2use super::ParallelIterator;
3
4use std::iter::{self, Sum};
5use std::marker::PhantomData;
6
7pub(super) fn sum<PI, S>(pi: PI) -> S
8where
9    PI: ParallelIterator,
10    S: Send + Sum<PI::Item> + Sum,
11{
12    pi.drive_unindexed(SumConsumer::new())
13}
14
15fn add<T: Sum>(left: T, right: T) -> T {
16    [left, right].into_iter().sum()
17}
18
19struct SumConsumer<S: Send> {
20    _marker: PhantomData<*const S>,
21}
22
23unsafe impl<S: Send> Send for SumConsumer<S> {}
24
25impl<S: Send> SumConsumer<S> {
26    fn new() -> SumConsumer<S> {
27        SumConsumer {
28            _marker: PhantomData,
29        }
30    }
31}
32
33impl<S, T> Consumer<T> for SumConsumer<S>
34where
35    S: Send + Sum<T> + Sum,
36{
37    type Folder = SumFolder<S>;
38    type Reducer = Self;
39    type Result = S;
40
41    fn split_at(self, _index: usize) -> (Self, Self, Self) {
42        (SumConsumer::new(), SumConsumer::new(), SumConsumer::new())
43    }
44
45    fn into_folder(self) -> Self::Folder {
46        SumFolder {
47            sum: iter::empty::<T>().sum(),
48        }
49    }
50
51    fn full(&self) -> bool {
52        false
53    }
54}
55
56impl<S, T> UnindexedConsumer<T> for SumConsumer<S>
57where
58    S: Send + Sum<T> + Sum,
59{
60    fn split_off_left(&self) -> Self {
61        SumConsumer::new()
62    }
63
64    fn to_reducer(&self) -> Self::Reducer {
65        SumConsumer::new()
66    }
67}
68
69impl<S> Reducer<S> for SumConsumer<S>
70where
71    S: Send + Sum,
72{
73    fn reduce(self, left: S, right: S) -> S {
74        add(left, right)
75    }
76}
77
78struct SumFolder<S> {
79    sum: S,
80}
81
82impl<S, T> Folder<T> for SumFolder<S>
83where
84    S: Sum<T> + Sum,
85{
86    type Result = S;
87
88    fn consume(self, item: T) -> Self {
89        SumFolder {
90            sum: add(self.sum, iter::once(item).sum()),
91        }
92    }
93
94    fn consume_iter<I>(self, iter: I) -> Self
95    where
96        I: IntoIterator<Item = T>,
97    {
98        SumFolder {
99            sum: add(self.sum, iter.into_iter().sum()),
100        }
101    }
102
103    fn complete(self) -> S {
104        self.sum
105    }
106
107    fn full(&self) -> bool {
108        false
109    }
110}
rayon/iter/sum.rs

rayon/iter/
sum.rs
