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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177

use super::{Consumer, Driver, Executor, IntoParallelIterator, ParallelIterator, Reducer};

/// `ParallelExtend` extends an existing collection with items from a [`ParallelIterator`].
///
/// [`ParallelIterator`]: trait.ParallelIterator.html
///
/// # Examples
///
/// Implementing `ParallelExtend` for your type:
///
/// ```
/// use asparit::*;
/// use std::mem;
///
/// struct BlackHole {
///     mass: usize,
/// }
///
/// impl<'a, I> ParallelExtend<'a, I, BlackHoleFolder<'a>> for &'a mut BlackHole
/// where
///     I: Send + 'a,
/// {
///     type Consumer = BlackHoleConsumer<'a>;
///
///     fn into_consumer(self) -> Self::Consumer {
///         BlackHoleConsumer(Some(self))
///     }
///
///     fn map_result(ret: BlackHoleFolder<'a>) -> Self {
///         let bh = ret.bh.unwrap();
///
///         bh.mass += ret.mass;
///
///         bh
///     }
/// }
///
/// struct BlackHoleConsumer<'a>(Option<&'a mut BlackHole>);
///
/// impl WithSetup for BlackHoleConsumer<'_> {}
///
/// impl<'a, I> Consumer<I> for BlackHoleConsumer<'a> {
///     type Folder = BlackHoleFolder<'a>;
///     type Reducer = BlackHoleReducer;
///     type Result = BlackHoleFolder<'a>;
///
///     fn split(self) -> (Self, Self, Self::Reducer) {
///         (
///             BlackHoleConsumer(self.0),
///             BlackHoleConsumer(None),
///             BlackHoleReducer,
///         )
///     }
///
///     fn split_at(self, _index: usize) -> (Self, Self, Self::Reducer) {
///         (
///             BlackHoleConsumer(self.0),
///             BlackHoleConsumer(None),
///             BlackHoleReducer,
///         )
///     }
///
///     fn into_folder(self) -> Self::Folder {
///         BlackHoleFolder {
///             bh: self.0,
///             mass: 0,
///         }
///     }
/// }
///
/// struct BlackHoleFolder<'a> {
///     bh: Option<&'a mut BlackHole>,
///     mass: usize,
/// }
///
/// impl<'a, I> Folder<I> for BlackHoleFolder<'a> {
///     type Result = Self;
///
///     fn consume(mut self, _item: I) -> Self {
///         self.mass += std::mem::size_of::<I>();
///
///         self
///     }
///
///     fn consume_iter<X>(mut self, iter: X) -> Self
///     where
///         X: IntoIterator<Item = I>,
///     {
///         self.mass += iter.into_iter().count() * std::mem::size_of::<I>();
///
///         self
///     }
///
///     fn complete(self) -> Self::Result {
///         self
///     }
/// }
///
/// struct BlackHoleReducer;
///
/// impl<'a> Reducer<BlackHoleFolder<'a>> for BlackHoleReducer {
///     fn reduce(
///         self,
///         left: BlackHoleFolder<'a>,
///         right: BlackHoleFolder<'a>,
///     ) -> BlackHoleFolder<'a> {
///         BlackHoleFolder {
///             bh: left.bh.or(right.bh),
///             mass: left.mass + right.mass,
///         }
///     }
/// }
///
/// let mut bh = BlackHole { mass: 0 };
///
/// bh.par_extend(0i32..1000).exec();
/// assert_eq!(bh.mass, 4000);
///
/// bh.par_extend(0i64..10).exec();
/// assert_eq!(bh.mass, 4080);
/// ```
pub trait ParallelExtend<'a, I, T>: Send + Sized
where
    I: Send + 'a,
    T: Send,
    <Self::Consumer as Consumer<I>>::Reducer: Reducer<T>,
{
    type Consumer: Consumer<I, Result = T> + 'a;

    fn par_extend<X>(self, iter: X) -> ParallelExtendDriver<'a, X::Iter, Self, T>
    where
        X: IntoParallelIterator<'a, Item = I>,
    {
        ParallelExtendDriver {
            iterator: iter.into_par_iter(),
            consumer: self.into_consumer(),
        }
    }

    /// Creates a consumer that is used to handle the items from the iterator.
    fn into_consumer(self) -> Self::Consumer;

    /// Converts the result of the consumer into the final type
    fn map_result(inner: <Self::Consumer as Consumer<I>>::Result) -> Self;
}

pub struct ParallelExtendDriver<'a, X, S, T>
where
    X: ParallelIterator<'a>,
    S: ParallelExtend<'a, X::Item, T>,
    <S::Consumer as Consumer<X::Item>>::Reducer: Reducer<T>,
    T: Send,
{
    iterator: X,
    consumer: S::Consumer,
}

impl<'a, X, S, T> Driver<'a, S, T> for ParallelExtendDriver<'a, X, S, T>
where
    X: ParallelIterator<'a>,
    S: ParallelExtend<'a, X::Item, T> + Send + 'a,
    <S::Consumer as Consumer<X::Item>>::Reducer: Reducer<T> + Send,
    T: Send + 'a,
{
    fn exec_with<E>(self, executor: E) -> E::Result
    where
        E: Executor<'a, S, T>,
    {
        let iterator = self.iterator;
        let consumer = self.consumer;
        let executor = executor.into_inner();

        let ret = iterator.drive(executor, consumer);

        E::map(ret, S::map_result)
    }
}