use serde::{Deserialize, Serialize};
use std::marker::PhantomData;
use super::{
DistributedIteratorMulti, DistributedReducer, ReduceFactory, Reducer, ReducerA, SumReducer
};
#[must_use]
pub struct Count<I> {
i: I,
}
impl<I> Count<I> {
pub(super) fn new(i: I) -> Self {
Self { i }
}
}
impl<I: DistributedIteratorMulti<Source>, Source> DistributedReducer<I, Source, usize> for Count<I>
where
I::Item: 'static,
{
type ReduceAFactory = CountReducerFactory<I::Item>;
type ReduceA = CountReducer<I::Item>;
type ReduceB = SumReducer<usize, usize>;
fn reducers(self) -> (I, Self::ReduceAFactory, Self::ReduceB) {
(
self.i,
CountReducerFactory(PhantomData),
SumReducer(0, PhantomData),
)
}
}
pub struct CountReducerFactory<A>(PhantomData<fn(A)>);
impl<A> ReduceFactory for CountReducerFactory<A> {
type Reducer = CountReducer<A>;
fn make(&self) -> Self::Reducer {
CountReducer(0, PhantomData)
}
}
#[derive(Serialize, Deserialize)]
#[serde(bound = "")]
pub struct CountReducer<A>(usize, PhantomData<fn(A)>);
impl<A> Reducer for CountReducer<A> {
type Item = A;
type Output = usize;
#[inline(always)]
fn push(&mut self, _item: Self::Item) -> bool {
self.0 += 1;
true
}
fn ret(self) -> Self::Output {
self.0
}
}
impl<A> ReducerA for CountReducer<A>
where
A: 'static,
{
type Output = usize;
}