#![allow(clippy::type_complexity)]
use derive_new::new;
use educe::Educe;
use itertools::Itertools;
use replace_with::replace_with_or_default;
use serde::{Deserialize, Serialize};
use std::{collections::HashMap, hash::Hash, marker::PhantomData};
use super::{folder_par_sink, FolderSync, FolderSyncReducer, ParallelPipe, ParallelSink};
#[derive(new)]
#[must_use]
pub struct Histogram<P> {
pipe: P,
}
impl_par_dist! {
impl<P: ParallelPipe<Item>, Item> ParallelSink<Item> for Histogram<P>
where
P::Output: Hash + Ord + Send + 'static,
{
folder_par_sink!(HistogramFolder<P::Output, StepA>, HistogramFolder<P::Output, StepB>, self, HistogramFolder::new(), HistogramFolder::new());
}
}
#[derive(Educe, Serialize, Deserialize, new)]
#[educe(Clone)]
#[serde(bound = "")]
pub struct HistogramFolder<B, Step> {
marker: PhantomData<fn() -> (B, Step)>,
}
pub struct StepA;
pub struct StepB;
impl<Item> FolderSync<Item> for HistogramFolder<Item, StepA>
where
Item: Hash + Ord,
{
type State = HashMap<Item, usize>;
type Done = Self::State;
fn zero(&mut self) -> Self::State {
HashMap::new()
}
fn push(&mut self, state: &mut Self::Done, item: Item) {
*state.entry(item).or_insert(0) += 1;
}
fn done(&mut self, state: Self::State) -> Self::Done {
state
}
}
impl<B> FolderSync<HashMap<B, usize>> for HistogramFolder<B, StepB>
where
B: Hash + Ord,
{
type State = Vec<(B, usize)>;
type Done = Self::State;
fn zero(&mut self) -> Self::State {
Vec::new()
}
fn push(&mut self, state: &mut Self::State, b: HashMap<B, usize>) {
let mut b = b.into_iter().collect::<Vec<_>>();
b.sort_by(|a, b| a.0.cmp(&b.0));
replace_with_or_default(state, |state| {
state
.into_iter()
.merge(b)
.coalesce(|a, b| {
if a.0 == b.0 {
Ok((a.0, a.1 + b.1))
} else {
Err((a, b))
}
})
.collect()
})
}
fn done(&mut self, state: Self::State) -> Self::Done {
state
}
}
impl<B> FolderSync<Vec<(B, usize)>> for HistogramFolder<B, StepB>
where
B: Hash + Ord,
{
type State = Vec<(B, usize)>;
type Done = Self::State;
fn zero(&mut self) -> Self::State {
Vec::new()
}
fn push(&mut self, state: &mut Self::State, b: Vec<(B, usize)>) {
replace_with_or_default(state, |state| {
state
.into_iter()
.merge(b)
.coalesce(|a, b| {
if a.0 == b.0 {
Ok((a.0, a.1 + b.1))
} else {
Err((a, b))
}
})
.collect()
})
}
#[inline(always)]
fn done(&mut self, state: Self::State) -> Self::Done {
state
}
}