aboutsummaryrefslogtreecommitdiff
path: root/vendor/rayon/src/iter/enumerate.rs
diff options
context:
space:
mode:
Diffstat (limited to 'vendor/rayon/src/iter/enumerate.rs')
-rw-r--r--vendor/rayon/src/iter/enumerate.rs133
1 files changed, 133 insertions, 0 deletions
diff --git a/vendor/rayon/src/iter/enumerate.rs b/vendor/rayon/src/iter/enumerate.rs
new file mode 100644
index 0000000..980ee7c
--- /dev/null
+++ b/vendor/rayon/src/iter/enumerate.rs
@@ -0,0 +1,133 @@
+use super::plumbing::*;
+use super::*;
+use std::iter;
+use std::ops::Range;
+use std::usize;
+
+/// `Enumerate` is an iterator that returns the current count along with the element.
+/// This struct is created by the [`enumerate()`] method on [`IndexedParallelIterator`]
+///
+/// [`enumerate()`]: trait.IndexedParallelIterator.html#method.enumerate
+/// [`IndexedParallelIterator`]: trait.IndexedParallelIterator.html
+#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
+#[derive(Debug, Clone)]
+pub struct Enumerate<I: IndexedParallelIterator> {
+ base: I,
+}
+
+impl<I> Enumerate<I>
+where
+ I: IndexedParallelIterator,
+{
+ /// Creates a new `Enumerate` iterator.
+ pub(super) fn new(base: I) -> Self {
+ Enumerate { base }
+ }
+}
+
+impl<I> ParallelIterator for Enumerate<I>
+where
+ I: IndexedParallelIterator,
+{
+ type Item = (usize, I::Item);
+
+ fn drive_unindexed<C>(self, consumer: C) -> C::Result
+ where
+ C: UnindexedConsumer<Self::Item>,
+ {
+ bridge(self, consumer)
+ }
+
+ fn opt_len(&self) -> Option<usize> {
+ Some(self.len())
+ }
+}
+
+impl<I> IndexedParallelIterator for Enumerate<I>
+where
+ I: IndexedParallelIterator,
+{
+ fn drive<C: Consumer<Self::Item>>(self, consumer: C) -> C::Result {
+ bridge(self, consumer)
+ }
+
+ fn len(&self) -> usize {
+ self.base.len()
+ }
+
+ fn with_producer<CB>(self, callback: CB) -> CB::Output
+ where
+ CB: ProducerCallback<Self::Item>,
+ {
+ return self.base.with_producer(Callback { callback });
+
+ struct Callback<CB> {
+ callback: CB,
+ }
+
+ impl<I, CB> ProducerCallback<I> for Callback<CB>
+ where
+ CB: ProducerCallback<(usize, I)>,
+ {
+ type Output = CB::Output;
+ fn callback<P>(self, base: P) -> CB::Output
+ where
+ P: Producer<Item = I>,
+ {
+ let producer = EnumerateProducer { base, offset: 0 };
+ self.callback.callback(producer)
+ }
+ }
+ }
+}
+
+/// ////////////////////////////////////////////////////////////////////////
+/// Producer implementation
+
+struct EnumerateProducer<P> {
+ base: P,
+ offset: usize,
+}
+
+impl<P> Producer for EnumerateProducer<P>
+where
+ P: Producer,
+{
+ type Item = (usize, P::Item);
+ type IntoIter = iter::Zip<Range<usize>, P::IntoIter>;
+
+ fn into_iter(self) -> Self::IntoIter {
+ // Enumerate only works for IndexedParallelIterators. Since those
+ // have a max length of usize::MAX, their max index is
+ // usize::MAX - 1, so the range 0..usize::MAX includes all
+ // possible indices.
+ //
+ // However, we should to use a precise end to the range, otherwise
+ // reversing the iterator may have to walk back a long ways before
+ // `Zip::next_back` can produce anything.
+ let base = self.base.into_iter();
+ let end = self.offset + base.len();
+ (self.offset..end).zip(base)
+ }
+
+ fn min_len(&self) -> usize {
+ self.base.min_len()
+ }
+ fn max_len(&self) -> usize {
+ self.base.max_len()
+ }
+
+ fn split_at(self, index: usize) -> (Self, Self) {
+ let (left, right) = self.base.split_at(index);
+ (
+ EnumerateProducer {
+ base: left,
+ offset: self.offset,
+ },
+ EnumerateProducer {
+ base: right,
+ offset: self.offset + index,
+ },
+ )
+ }
+}