1 // Copyright (c) 2023 Huawei Device Co., Ltd.
2 // Licensed under the Apache License, Version 2.0 (the "License");
3 // you may not use this file except in compliance with the License.
4 // You may obtain a copy of the License at
5 //
6 // http://www.apache.org/licenses/LICENSE-2.0
7 //
8 // Unless required by applicable law or agreed to in writing, software
9 // distributed under the License is distributed on an "AS IS" BASIS,
10 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 // See the License for the specific language governing permissions and
12 // limitations under the License.
13
14 use std::iter;
15
16 use super::ParallelIterator;
17
map<P, F>(par_iter: P, map_op: F) -> Map<P, F>18 pub fn map<P, F>(par_iter: P, map_op: F) -> Map<P, F> {
19 Map {
20 base: par_iter,
21 map_op,
22 }
23 }
24
25 #[must_use = "iterators are lazy and do nothing unless consumed"]
26 pub struct Map<P, F> {
27 base: P,
28 map_op: F,
29 }
30
31 impl<P, F, B> ParallelIterator for Map<P, F>
32 where
33 P: ParallelIterator,
34 F: Fn(P::Item) -> B + Copy + Send,
35 {
36 type Item = B;
37 type Iter = iter::Map<P::Iter, F>;
38
len(&self) -> usize39 fn len(&self) -> usize {
40 self.base.len()
41 }
42
reduce(self, len: usize) -> Self43 fn reduce(self, len: usize) -> Self {
44 Self {
45 base: self.base.reduce(len),
46 map_op: self.map_op,
47 }
48 }
49
split(self) -> (Self, Option<Self>)50 fn split(self) -> (Self, Option<Self>) {
51 let map_op = self.map_op;
52 let (left, right) = self.base.split();
53 (
54 Map { base: left, map_op },
55 right.map(|right| Map {
56 base: right,
57 map_op,
58 }),
59 )
60 }
61
iter(self) -> Self::Iter62 fn iter(self) -> Self::Iter {
63 self.base.iter().map(self.map_op)
64 }
65 }
66