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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 14:29:10 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 14:29:10 +0000
commit2aa4a82499d4becd2284cdb482213d541b8804dd (patch)
treeb80bf8bf13c3766139fbacc530efd0dd9d54394c /third_party/rust/cranelift-codegen/src/iterators.rs
parentInitial commit. (diff)
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Adding upstream version 86.0.1.upstream/86.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/cranelift-codegen/src/iterators.rs')
-rw-r--r--third_party/rust/cranelift-codegen/src/iterators.rs93
1 files changed, 93 insertions, 0 deletions
diff --git a/third_party/rust/cranelift-codegen/src/iterators.rs b/third_party/rust/cranelift-codegen/src/iterators.rs
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+++ b/third_party/rust/cranelift-codegen/src/iterators.rs
@@ -0,0 +1,93 @@
+//! Iterator utilities.
+
+/// Extra methods for iterators.
+pub trait IteratorExtras: Iterator {
+ /// Create an iterator that produces adjacent pairs of elements from the iterator.
+ fn adjacent_pairs(mut self) -> AdjacentPairs<Self>
+ where
+ Self: Sized,
+ Self::Item: Clone,
+ {
+ let elem = self.next();
+ AdjacentPairs { iter: self, elem }
+ }
+}
+
+impl<T> IteratorExtras for T where T: Iterator {}
+
+/// Adjacent pairs iterator returned by `adjacent_pairs()`.
+///
+/// This wraps another iterator and produces a sequence of adjacent pairs of elements.
+pub struct AdjacentPairs<I>
+where
+ I: Iterator,
+ I::Item: Clone,
+{
+ iter: I,
+ elem: Option<I::Item>,
+}
+
+impl<I> Iterator for AdjacentPairs<I>
+where
+ I: Iterator,
+ I::Item: Clone,
+{
+ type Item = (I::Item, I::Item);
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.elem.take().and_then(|e| {
+ self.elem = self.iter.next();
+ self.elem.clone().map(|n| (e, n))
+ })
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use alloc::vec::Vec;
+
+ #[test]
+ fn adjpairs() {
+ use super::IteratorExtras;
+
+ assert_eq!(
+ [1, 2, 3, 4]
+ .iter()
+ .cloned()
+ .adjacent_pairs()
+ .collect::<Vec<_>>(),
+ vec![(1, 2), (2, 3), (3, 4)]
+ );
+ assert_eq!(
+ [2, 3, 4]
+ .iter()
+ .cloned()
+ .adjacent_pairs()
+ .collect::<Vec<_>>(),
+ vec![(2, 3), (3, 4)]
+ );
+ assert_eq!(
+ [2, 3, 4]
+ .iter()
+ .cloned()
+ .adjacent_pairs()
+ .collect::<Vec<_>>(),
+ vec![(2, 3), (3, 4)]
+ );
+ assert_eq!(
+ [3, 4].iter().cloned().adjacent_pairs().collect::<Vec<_>>(),
+ vec![(3, 4)]
+ );
+ assert_eq!(
+ [4].iter().cloned().adjacent_pairs().collect::<Vec<_>>(),
+ vec![]
+ );
+ assert_eq!(
+ [].iter()
+ .cloned()
+ .adjacent_pairs()
+ .collect::<Vec<(i32, i32)>>(),
+ vec![]
+ );
+ }
+}