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use super::plumbing::*;
use super::*;
use std::fmt::{self, Debug};
impl<U, I, ID, F> Fold<I, ID, F>
where
I: ParallelIterator,
F: Fn(U, I::Item) -> U + Sync + Send,
ID: Fn() -> U + Sync + Send,
U: Send,
{
pub(super) fn new(base: I, identity: ID, fold_op: F) -> Self {
Fold {
base,
identity,
fold_op,
}
}
}
/// `Fold` is an iterator that applies a function over an iterator producing a single value.
/// This struct is created by the [`fold()`] method on [`ParallelIterator`]
///
/// [`fold()`]: trait.ParallelIterator.html#method.fold
/// [`ParallelIterator`]: trait.ParallelIterator.html
#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
#[derive(Clone)]
pub struct Fold<I, ID, F> {
base: I,
identity: ID,
fold_op: F,
}
impl<I: ParallelIterator + Debug, ID, F> Debug for Fold<I, ID, F> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Fold").field("base", &self.base).finish()
}
}
impl<U, I, ID, F> ParallelIterator for Fold<I, ID, F>
where
I: ParallelIterator,
F: Fn(U, I::Item) -> U + Sync + Send,
ID: Fn() -> U + Sync + Send,
U: Send,
{
type Item = U;
fn drive_unindexed<C>(self, consumer: C) -> C::Result
where
C: UnindexedConsumer<Self::Item>,
{
let consumer1 = FoldConsumer {
base: consumer,
fold_op: &self.fold_op,
identity: &self.identity,
};
self.base.drive_unindexed(consumer1)
}
}
struct FoldConsumer<'c, C, ID, F> {
base: C,
fold_op: &'c F,
identity: &'c ID,
}
impl<'r, U, T, C, ID, F> Consumer<T> for FoldConsumer<'r, C, ID, F>
where
C: Consumer<U>,
F: Fn(U, T) -> U + Sync,
ID: Fn() -> U + Sync,
U: Send,
{
type Folder = FoldFolder<'r, C::Folder, U, F>;
type Reducer = C::Reducer;
type Result = C::Result;
fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) {
let (left, right, reducer) = self.base.split_at(index);
(
FoldConsumer { base: left, ..self },
FoldConsumer {
base: right,
..self
},
reducer,
)
}
fn into_folder(self) -> Self::Folder {
FoldFolder {
base: self.base.into_folder(),
item: (self.identity)(),
fold_op: self.fold_op,
}
}
fn full(&self) -> bool {
self.base.full()
}
}
impl<'r, U, T, C, ID, F> UnindexedConsumer<T> for FoldConsumer<'r, C, ID, F>
where
C: UnindexedConsumer<U>,
F: Fn(U, T) -> U + Sync,
ID: Fn() -> U + Sync,
U: Send,
{
fn split_off_left(&self) -> Self {
FoldConsumer {
base: self.base.split_off_left(),
..*self
}
}
fn to_reducer(&self) -> Self::Reducer {
self.base.to_reducer()
}
}
struct FoldFolder<'r, C, ID, F> {
base: C,
fold_op: &'r F,
item: ID,
}
impl<'r, C, ID, F, T> Folder<T> for FoldFolder<'r, C, ID, F>
where
C: Folder<ID>,
F: Fn(ID, T) -> ID + Sync,
{
type Result = C::Result;
fn consume(self, item: T) -> Self {
let item = (self.fold_op)(self.item, item);
FoldFolder {
base: self.base,
fold_op: self.fold_op,
item,
}
}
fn consume_iter<I>(self, iter: I) -> Self
where
I: IntoIterator<Item = T>,
{
fn not_full<C, ID, T>(base: &C) -> impl Fn(&T) -> bool + '_
where
C: Folder<ID>,
{
move |_| !base.full()
}
let base = self.base;
let item = iter
.into_iter()
// stop iterating if another thread has finished
.take_while(not_full(&base))
.fold(self.item, self.fold_op);
FoldFolder {
base,
item,
fold_op: self.fold_op,
}
}
fn complete(self) -> C::Result {
self.base.consume(self.item).complete()
}
fn full(&self) -> bool {
self.base.full()
}
}
// ///////////////////////////////////////////////////////////////////////////
impl<U, I, F> FoldWith<I, U, F>
where
I: ParallelIterator,
F: Fn(U, I::Item) -> U + Sync + Send,
U: Send + Clone,
{
pub(super) fn new(base: I, item: U, fold_op: F) -> Self {
FoldWith {
base,
item,
fold_op,
}
}
}
/// `FoldWith` is an iterator that applies a function over an iterator producing a single value.
/// This struct is created by the [`fold_with()`] method on [`ParallelIterator`]
///
/// [`fold_with()`]: trait.ParallelIterator.html#method.fold_with
/// [`ParallelIterator`]: trait.ParallelIterator.html
#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
#[derive(Clone)]
pub struct FoldWith<I, U, F> {
base: I,
item: U,
fold_op: F,
}
impl<I: ParallelIterator + Debug, U: Debug, F> Debug for FoldWith<I, U, F> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("FoldWith")
.field("base", &self.base)
.field("item", &self.item)
.finish()
}
}
impl<U, I, F> ParallelIterator for FoldWith<I, U, F>
where
I: ParallelIterator,
F: Fn(U, I::Item) -> U + Sync + Send,
U: Send + Clone,
{
type Item = U;
fn drive_unindexed<C>(self, consumer: C) -> C::Result
where
C: UnindexedConsumer<Self::Item>,
{
let consumer1 = FoldWithConsumer {
base: consumer,
item: self.item,
fold_op: &self.fold_op,
};
self.base.drive_unindexed(consumer1)
}
}
struct FoldWithConsumer<'c, C, U, F> {
base: C,
item: U,
fold_op: &'c F,
}
impl<'r, U, T, C, F> Consumer<T> for FoldWithConsumer<'r, C, U, F>
where
C: Consumer<U>,
F: Fn(U, T) -> U + Sync,
U: Send + Clone,
{
type Folder = FoldFolder<'r, C::Folder, U, F>;
type Reducer = C::Reducer;
type Result = C::Result;
fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) {
let (left, right, reducer) = self.base.split_at(index);
(
FoldWithConsumer {
base: left,
item: self.item.clone(),
..self
},
FoldWithConsumer {
base: right,
..self
},
reducer,
)
}
fn into_folder(self) -> Self::Folder {
FoldFolder {
base: self.base.into_folder(),
item: self.item,
fold_op: self.fold_op,
}
}
fn full(&self) -> bool {
self.base.full()
}
}
impl<'r, U, T, C, F> UnindexedConsumer<T> for FoldWithConsumer<'r, C, U, F>
where
C: UnindexedConsumer<U>,
F: Fn(U, T) -> U + Sync,
U: Send + Clone,
{
fn split_off_left(&self) -> Self {
FoldWithConsumer {
base: self.base.split_off_left(),
item: self.item.clone(),
..*self
}
}
fn to_reducer(&self) -> Self::Reducer {
self.base.to_reducer()
}
}