From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 7 Apr 2024 21:33:14 +0200
Subject: Adding upstream version 115.7.0esr.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 third_party/rust/rayon/src/iter/chunks.rs | 226 ++++++++++++++++++++++++++++++
 1 file changed, 226 insertions(+)
 create mode 100644 third_party/rust/rayon/src/iter/chunks.rs

(limited to 'third_party/rust/rayon/src/iter/chunks.rs')

diff --git a/third_party/rust/rayon/src/iter/chunks.rs b/third_party/rust/rayon/src/iter/chunks.rs
new file mode 100644
index 0000000000..ec48278d02
--- /dev/null
+++ b/third_party/rust/rayon/src/iter/chunks.rs
@@ -0,0 +1,226 @@
+use std::cmp::min;
+
+use super::plumbing::*;
+use super::*;
+use crate::math::div_round_up;
+
+/// `Chunks` is an iterator that groups elements of an underlying iterator.
+///
+/// This struct is created by the [`chunks()`] method on [`IndexedParallelIterator`]
+///
+/// [`chunks()`]: trait.IndexedParallelIterator.html#method.chunks
+/// [`IndexedParallelIterator`]: trait.IndexedParallelIterator.html
+#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
+#[derive(Debug, Clone)]
+pub struct Chunks<I>
+where
+    I: IndexedParallelIterator,
+{
+    size: usize,
+    i: I,
+}
+
+impl<I> Chunks<I>
+where
+    I: IndexedParallelIterator,
+{
+    /// Creates a new `Chunks` iterator
+    pub(super) fn new(i: I, size: usize) -> Self {
+        Chunks { i, size }
+    }
+}
+
+impl<I> ParallelIterator for Chunks<I>
+where
+    I: IndexedParallelIterator,
+{
+    type Item = Vec<I::Item>;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: Consumer<Vec<I::Item>>,
+    {
+        bridge(self, consumer)
+    }
+
+    fn opt_len(&self) -> Option<usize> {
+        Some(self.len())
+    }
+}
+
+impl<I> IndexedParallelIterator for Chunks<I>
+where
+    I: IndexedParallelIterator,
+{
+    fn drive<C>(self, consumer: C) -> C::Result
+    where
+        C: Consumer<Self::Item>,
+    {
+        bridge(self, consumer)
+    }
+
+    fn len(&self) -> usize {
+        div_round_up(self.i.len(), self.size)
+    }
+
+    fn with_producer<CB>(self, callback: CB) -> CB::Output
+    where
+        CB: ProducerCallback<Self::Item>,
+    {
+        let len = self.i.len();
+        return self.i.with_producer(Callback {
+            size: self.size,
+            len,
+            callback,
+        });
+
+        struct Callback<CB> {
+            size: usize,
+            len: usize,
+            callback: CB,
+        }
+
+        impl<T, CB> ProducerCallback<T> for Callback<CB>
+        where
+            CB: ProducerCallback<Vec<T>>,
+        {
+            type Output = CB::Output;
+
+            fn callback<P>(self, base: P) -> CB::Output
+            where
+                P: Producer<Item = T>,
+            {
+                let producer = ChunkProducer::new(self.size, self.len, base, Vec::from_iter);
+                self.callback.callback(producer)
+            }
+        }
+    }
+}
+
+pub(super) struct ChunkProducer<P, F> {
+    chunk_size: usize,
+    len: usize,
+    base: P,
+    map: F,
+}
+
+impl<P, F> ChunkProducer<P, F> {
+    pub(super) fn new(chunk_size: usize, len: usize, base: P, map: F) -> Self {
+        Self {
+            chunk_size,
+            len,
+            base,
+            map,
+        }
+    }
+}
+
+impl<P, F, T> Producer for ChunkProducer<P, F>
+where
+    P: Producer,
+    F: Fn(P::IntoIter) -> T + Send + Clone,
+{
+    type Item = T;
+    type IntoIter = std::iter::Map<ChunkSeq<P>, F>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        let chunks = ChunkSeq {
+            chunk_size: self.chunk_size,
+            len: self.len,
+            inner: if self.len > 0 { Some(self.base) } else { None },
+        };
+        chunks.map(self.map)
+    }
+
+    fn split_at(self, index: usize) -> (Self, Self) {
+        let elem_index = min(index * self.chunk_size, self.len);
+        let (left, right) = self.base.split_at(elem_index);
+        (
+            ChunkProducer {
+                chunk_size: self.chunk_size,
+                len: elem_index,
+                base: left,
+                map: self.map.clone(),
+            },
+            ChunkProducer {
+                chunk_size: self.chunk_size,
+                len: self.len - elem_index,
+                base: right,
+                map: self.map,
+            },
+        )
+    }
+
+    fn min_len(&self) -> usize {
+        div_round_up(self.base.min_len(), self.chunk_size)
+    }
+
+    fn max_len(&self) -> usize {
+        self.base.max_len() / self.chunk_size
+    }
+}
+
+pub(super) struct ChunkSeq<P> {
+    chunk_size: usize,
+    len: usize,
+    inner: Option<P>,
+}
+
+impl<P> Iterator for ChunkSeq<P>
+where
+    P: Producer,
+{
+    type Item = P::IntoIter;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let producer = self.inner.take()?;
+        if self.len > self.chunk_size {
+            let (left, right) = producer.split_at(self.chunk_size);
+            self.inner = Some(right);
+            self.len -= self.chunk_size;
+            Some(left.into_iter())
+        } else {
+            debug_assert!(self.len > 0);
+            self.len = 0;
+            Some(producer.into_iter())
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.len();
+        (len, Some(len))
+    }
+}
+
+impl<P> ExactSizeIterator for ChunkSeq<P>
+where
+    P: Producer,
+{
+    #[inline]
+    fn len(&self) -> usize {
+        div_round_up(self.len, self.chunk_size)
+    }
+}
+
+impl<P> DoubleEndedIterator for ChunkSeq<P>
+where
+    P: Producer,
+{
+    fn next_back(&mut self) -> Option<Self::Item> {
+        let producer = self.inner.take()?;
+        if self.len > self.chunk_size {
+            let mut size = self.len % self.chunk_size;
+            if size == 0 {
+                size = self.chunk_size;
+            }
+            let (left, right) = producer.split_at(self.len - size);
+            self.inner = Some(left);
+            self.len -= size;
+            Some(right.into_iter())
+        } else {
+            debug_assert!(self.len > 0);
+            self.len = 0;
+            Some(producer.into_iter())
+        }
+    }
+}
-- 
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