/rust/registry/src/index.crates.io-6f17d22bba15001f/rayon-1.10.0/src/iter/fold.rs

Source (jump to first uncovered line)
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()
    }
}

Coverage Report

Created: 2025-07-18 06:49

Line	Count	Source (jump to first uncovered line)
1		use super::plumbing::*;
2		use super::*;
3
4		use std::fmt::{self, Debug};
5
6		impl<U, I, ID, F> Fold<I, ID, F>
7		where
8		I: ParallelIterator,
9		F: Fn(U, I::Item) -> U + Sync + Send,
10		ID: Fn() -> U + Sync + Send,
11		U: Send,
12		{
13	0	pub(super) fn new(base: I, identity: ID, fold_op: F) -> Self {
14	0	Fold {
15	0	base,
16	0	identity,
17	0	fold_op,
18	0	}
19	0	}
20		}
21
22		/// `Fold` is an iterator that applies a function over an iterator producing a single value.
23		/// This struct is created by the [`fold()`] method on [`ParallelIterator`]
24		///
25		/// [`fold()`]: trait.ParallelIterator.html#method.fold
26		/// [`ParallelIterator`]: trait.ParallelIterator.html
27		#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
28		#[derive(Clone)]
29		pub struct Fold<I, ID, F> {
30		base: I,
31		identity: ID,
32		fold_op: F,
33		}
34
35		impl<I: ParallelIterator + Debug, ID, F> Debug for Fold<I, ID, F> {
36	0	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
37	0	f.debug_struct("Fold").field("base", &self.base).finish()
38	0	}
39		}
40
41		impl<U, I, ID, F> ParallelIterator for Fold<I, ID, F>
42		where
43		I: ParallelIterator,
44		F: Fn(U, I::Item) -> U + Sync + Send,
45		ID: Fn() -> U + Sync + Send,
46		U: Send,
47		{
48		type Item = U;
49
50	0	fn drive_unindexed<C>(self, consumer: C) -> C::Result
51	0	where
52	0	C: UnindexedConsumer<Self::Item>,
53	0	{
54	0	let consumer1 = FoldConsumer {
55	0	base: consumer,
56	0	fold_op: &self.fold_op,
57	0	identity: &self.identity,
58	0	};
59	0	self.base.drive_unindexed(consumer1)
60	0	}
61		}
62
63		struct FoldConsumer<'c, C, ID, F> {
64		base: C,
65		fold_op: &'c F,
66		identity: &'c ID,
67		}
68
69		impl<'r, U, T, C, ID, F> Consumer<T> for FoldConsumer<'r, C, ID, F>
70		where
71		C: Consumer<U>,
72		F: Fn(U, T) -> U + Sync,
73		ID: Fn() -> U + Sync,
74		U: Send,
75		{
76		type Folder = FoldFolder<'r, C::Folder, U, F>;
77		type Reducer = C::Reducer;
78		type Result = C::Result;
79
80	0	fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) {
81	0	let (left, right, reducer) = self.base.split_at(index);
82	0	(
83	0	FoldConsumer { base: left, ..self },
84	0	FoldConsumer {
85	0	base: right,
86	0	..self
87	0	},
88	0	reducer,
89	0	)
90	0	}
91
92	0	fn into_folder(self) -> Self::Folder {
93	0	FoldFolder {
94	0	base: self.base.into_folder(),
95	0	item: (self.identity)(),
96	0	fold_op: self.fold_op,
97	0	}
98	0	}
99
100	0	fn full(&self) -> bool {
101	0	self.base.full()
102	0	}
103		}
104
105		impl<'r, U, T, C, ID, F> UnindexedConsumer<T> for FoldConsumer<'r, C, ID, F>
106		where
107		C: UnindexedConsumer<U>,
108		F: Fn(U, T) -> U + Sync,
109		ID: Fn() -> U + Sync,
110		U: Send,
111		{
112	0	fn split_off_left(&self) -> Self {
113	0	FoldConsumer {
114	0	base: self.base.split_off_left(),
115	0	..*self
116	0	}
117	0	}
118
119	0	fn to_reducer(&self) -> Self::Reducer {
120	0	self.base.to_reducer()
121	0	}
122		}
123
124		struct FoldFolder<'r, C, ID, F> {
125		base: C,
126		fold_op: &'r F,
127		item: ID,
128		}
129
130		impl<'r, C, ID, F, T> Folder<T> for FoldFolder<'r, C, ID, F>
131		where
132		C: Folder<ID>,
133		F: Fn(ID, T) -> ID + Sync,
134		{
135		type Result = C::Result;
136
137	0	fn consume(self, item: T) -> Self {
138	0	let item = (self.fold_op)(self.item, item);
139	0	FoldFolder {
140	0	base: self.base,
141	0	fold_op: self.fold_op,
142	0	item,
143	0	}
144	0	}
145
146	0	fn consume_iter<I>(self, iter: I) -> Self
147	0	where
148	0	I: IntoIterator<Item = T>,
149	0	{
150	0	fn not_full<C, ID, T>(base: &C) -> impl Fn(&T) -> bool + '_
151	0	where
152	0	C: Folder<ID>,
153	0	{
154	0	move \|_\| !base.full()
155	0	}
156
157	0	let base = self.base;
158	0	let item = iter
159	0	.into_iter()
160	0	// stop iterating if another thread has finished
161	0	.take_while(not_full(&base))
162	0	.fold(self.item, self.fold_op);
163	0
164	0	FoldFolder {
165	0	base,
166	0	item,
167	0	fold_op: self.fold_op,
168	0	}
169	0	}
170
171	0	fn complete(self) -> C::Result {
172	0	self.base.consume(self.item).complete()
173	0	}
174
175	0	fn full(&self) -> bool {
176	0	self.base.full()
177	0	}
178		}
179
180		// ///////////////////////////////////////////////////////////////////////////
181
182		impl<U, I, F> FoldWith<I, U, F>
183		where
184		I: ParallelIterator,
185		F: Fn(U, I::Item) -> U + Sync + Send,
186		U: Send + Clone,
187		{
188	0	pub(super) fn new(base: I, item: U, fold_op: F) -> Self {
189	0	FoldWith {
190	0	base,
191	0	item,
192	0	fold_op,
193	0	}
194	0	}
195		}
196
197		/// `FoldWith` is an iterator that applies a function over an iterator producing a single value.
198		/// This struct is created by the [`fold_with()`] method on [`ParallelIterator`]
199		///
200		/// [`fold_with()`]: trait.ParallelIterator.html#method.fold_with
201		/// [`ParallelIterator`]: trait.ParallelIterator.html
202		#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
203		#[derive(Clone)]
204		pub struct FoldWith<I, U, F> {
205		base: I,
206		item: U,
207		fold_op: F,
208		}
209
210		impl<I: ParallelIterator + Debug, U: Debug, F> Debug for FoldWith<I, U, F> {
211	0	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
212	0	f.debug_struct("FoldWith")
213	0	.field("base", &self.base)
214	0	.field("item", &self.item)
215	0	.finish()
216	0	}
217		}
218
219		impl<U, I, F> ParallelIterator for FoldWith<I, U, F>
220		where
221		I: ParallelIterator,
222		F: Fn(U, I::Item) -> U + Sync + Send,
223		U: Send + Clone,
224		{
225		type Item = U;
226
227	0	fn drive_unindexed<C>(self, consumer: C) -> C::Result
228	0	where
229	0	C: UnindexedConsumer<Self::Item>,
230	0	{
231	0	let consumer1 = FoldWithConsumer {
232	0	base: consumer,
233	0	item: self.item,
234	0	fold_op: &self.fold_op,
235	0	};
236	0	self.base.drive_unindexed(consumer1)
237	0	}
238		}
239
240		struct FoldWithConsumer<'c, C, U, F> {
241		base: C,
242		item: U,
243		fold_op: &'c F,
244		}
245
246		impl<'r, U, T, C, F> Consumer<T> for FoldWithConsumer<'r, C, U, F>
247		where
248		C: Consumer<U>,
249		F: Fn(U, T) -> U + Sync,
250		U: Send + Clone,
251		{
252		type Folder = FoldFolder<'r, C::Folder, U, F>;
253		type Reducer = C::Reducer;
254		type Result = C::Result;
255
256	0	fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) {
257	0	let (left, right, reducer) = self.base.split_at(index);
258	0	(
259	0	FoldWithConsumer {
260	0	base: left,
261	0	item: self.item.clone(),
262	0	..self
263	0	},
264	0	FoldWithConsumer {
265	0	base: right,
266	0	..self
267	0	},
268	0	reducer,
269	0	)
270	0	}
271
272	0	fn into_folder(self) -> Self::Folder {
273	0	FoldFolder {
274	0	base: self.base.into_folder(),
275	0	item: self.item,
276	0	fold_op: self.fold_op,
277	0	}
278	0	}
279
280	0	fn full(&self) -> bool {
281	0	self.base.full()
282	0	}
283		}
284
285		impl<'r, U, T, C, F> UnindexedConsumer<T> for FoldWithConsumer<'r, C, U, F>
286		where
287		C: UnindexedConsumer<U>,
288		F: Fn(U, T) -> U + Sync,
289		U: Send + Clone,
290		{
291	0	fn split_off_left(&self) -> Self {
292	0	FoldWithConsumer {
293	0	base: self.base.split_off_left(),
294	0	item: self.item.clone(),
295	0	..*self
296	0	}
297	0	}
298
299	0	fn to_reducer(&self) -> Self::Reducer {
300	0	self.base.to_reducer()
301	0	}
302		}