Merging upstream version 1.76.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 220 insertions, 0 deletions

diff --git a/vendor/itertools-0.11.0/src/merge_join.rs b/vendor/itertools-0.11.0/src/merge_join.rs
new file mode 100644
index 000000000..84f7d0333
--- /dev/null
+++ b/vendor/itertools-0.11.0/src/merge_join.rs
@@ -0,0 +1,220 @@
+use std::cmp::Ordering;
+use std::iter::Fuse;
+use std::fmt;
+
+use either::Either;
+
+use super::adaptors::{PutBack, put_back};
+use crate::either_or_both::EitherOrBoth;
+use crate::size_hint::{self, SizeHint};
+#[cfg(doc)]
+use crate::Itertools;
+
+/// Return an iterator adaptor that merge-joins items from the two base iterators in ascending order.
+///
+/// [`IntoIterator`] enabled version of [`Itertools::merge_join_by`].
+pub fn merge_join_by<I, J, F, T>(left: I, right: J, cmp_fn: F)
+    -> MergeJoinBy<I::IntoIter, J::IntoIter, F>
+    where I: IntoIterator,
+          J: IntoIterator,
+          F: FnMut(&I::Item, &J::Item) -> T,
+          T: OrderingOrBool<I::Item, J::Item>,
+{
+    MergeJoinBy {
+        left: put_back(left.into_iter().fuse()),
+        right: put_back(right.into_iter().fuse()),
+        cmp_fn,
+    }
+}
+
+/// An iterator adaptor that merge-joins items from the two base iterators in ascending order.
+///
+/// See [`.merge_join_by()`](crate::Itertools::merge_join_by) for more information.
+#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
+pub struct MergeJoinBy<I: Iterator, J: Iterator, F> {
+    left: PutBack<Fuse<I>>,
+    right: PutBack<Fuse<J>>,
+    cmp_fn: F,
+}
+
+pub trait OrderingOrBool<L, R> {
+    type MergeResult;
+    fn left(left: L) -> Self::MergeResult;
+    fn right(right: R) -> Self::MergeResult;
+    // "merge" never returns (Some(...), Some(...), ...) so Option<Either<I::Item, J::Item>>
+    // is appealing but it is always followed by two put_backs, so we think the compiler is
+    // smart enough to optimize it. Or we could move put_backs into "merge".
+    fn merge(self, left: L, right: R) -> (Option<L>, Option<R>, Self::MergeResult);
+    fn size_hint(left: SizeHint, right: SizeHint) -> SizeHint;
+}
+
+impl<L, R> OrderingOrBool<L, R> for Ordering {
+    type MergeResult = EitherOrBoth<L, R>;
+    fn left(left: L) -> Self::MergeResult {
+        EitherOrBoth::Left(left)
+    }
+    fn right(right: R) -> Self::MergeResult {
+        EitherOrBoth::Right(right)
+    }
+    fn merge(self, left: L, right: R) -> (Option<L>, Option<R>, Self::MergeResult) {
+        match self {
+            Ordering::Equal => (None, None, EitherOrBoth::Both(left, right)),
+            Ordering::Less => (None, Some(right), EitherOrBoth::Left(left)),
+            Ordering::Greater => (Some(left), None, EitherOrBoth::Right(right)),
+        }
+    }
+    fn size_hint(left: SizeHint, right: SizeHint) -> SizeHint {
+        let (a_lower, a_upper) = left;
+        let (b_lower, b_upper) = right;
+        let lower = ::std::cmp::max(a_lower, b_lower);
+        let upper = match (a_upper, b_upper) {
+            (Some(x), Some(y)) => x.checked_add(y),
+            _ => None,
+        };
+        (lower, upper)
+    }
+}
+
+impl<L, R> OrderingOrBool<L, R> for bool {
+    type MergeResult = Either<L, R>;
+    fn left(left: L) -> Self::MergeResult {
+        Either::Left(left)
+    }
+    fn right(right: R) -> Self::MergeResult {
+        Either::Right(right)
+    }
+    fn merge(self, left: L, right: R) -> (Option<L>, Option<R>, Self::MergeResult) {
+        if self {
+            (None, Some(right), Either::Left(left))
+        } else {
+            (Some(left), None, Either::Right(right))
+        }
+    }
+    fn size_hint(left: SizeHint, right: SizeHint) -> SizeHint {
+        // Not ExactSizeIterator because size may be larger than usize
+        size_hint::add(left, right)
+    }
+}
+
+impl<I, J, F> Clone for MergeJoinBy<I, J, F>
+    where I: Iterator,
+          J: Iterator,
+          PutBack<Fuse<I>>: Clone,
+          PutBack<Fuse<J>>: Clone,
+          F: Clone,
+{
+    clone_fields!(left, right, cmp_fn);
+}
+
+impl<I, J, F> fmt::Debug for MergeJoinBy<I, J, F>
+    where I: Iterator + fmt::Debug,
+          I::Item: fmt::Debug,
+          J: Iterator + fmt::Debug,
+          J::Item: fmt::Debug,
+{
+    debug_fmt_fields!(MergeJoinBy, left, right);
+}
+
+impl<I, J, F, T> Iterator for MergeJoinBy<I, J, F>
+    where I: Iterator,
+          J: Iterator,
+          F: FnMut(&I::Item, &J::Item) -> T,
+          T: OrderingOrBool<I::Item, J::Item>,
+{
+    type Item = T::MergeResult;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match (self.left.next(), self.right.next()) {
+            (None, None) => None,
+            (Some(left), None) => Some(T::left(left)),
+            (None, Some(right)) => Some(T::right(right)),
+            (Some(left), Some(right)) => {
+                let (left, right, next) = (self.cmp_fn)(&left, &right).merge(left, right);
+                if let Some(left) = left {
+                    self.left.put_back(left);
+                }
+                if let Some(right) = right {
+                    self.right.put_back(right);
+                }
+                Some(next)
+            }
+        }
+    }
+
+    fn size_hint(&self) -> SizeHint {
+        T::size_hint(self.left.size_hint(), self.right.size_hint())
+    }
+
+    fn count(mut self) -> usize {
+        let mut count = 0;
+        loop {
+            match (self.left.next(), self.right.next()) {
+                (None, None) => break count,
+                (Some(_left), None) => break count + 1 + self.left.into_parts().1.count(),
+                (None, Some(_right)) => break count + 1 + self.right.into_parts().1.count(),
+                (Some(left), Some(right)) => {
+                    count += 1;
+                    let (left, right, _) = (self.cmp_fn)(&left, &right).merge(left, right);
+                    if let Some(left) = left {
+                        self.left.put_back(left);
+                    }
+                    if let Some(right) = right {
+                        self.right.put_back(right);
+                    }
+                }
+            }
+        }
+    }
+
+    fn last(mut self) -> Option<Self::Item> {
+        let mut previous_element = None;
+        loop {
+            match (self.left.next(), self.right.next()) {
+                (None, None) => break previous_element,
+                (Some(left), None) => {
+                    break Some(T::left(
+                        self.left.into_parts().1.last().unwrap_or(left),
+                    ))
+                }
+                (None, Some(right)) => {
+                    break Some(T::right(
+                        self.right.into_parts().1.last().unwrap_or(right),
+                    ))
+                }
+                (Some(left), Some(right)) => {
+                    let (left, right, elem) = (self.cmp_fn)(&left, &right).merge(left, right);
+                    if let Some(left) = left {
+                        self.left.put_back(left);
+                    }
+                    if let Some(right) = right {
+                        self.right.put_back(right);
+                    }
+                    previous_element = Some(elem);
+                }
+            }
+        }
+    }
+
+    fn nth(&mut self, mut n: usize) -> Option<Self::Item> {
+        loop {
+            if n == 0 {
+                break self.next();
+            }
+            n -= 1;
+            match (self.left.next(), self.right.next()) {
+                (None, None) => break None,
+                (Some(_left), None) => break self.left.nth(n).map(T::left),
+                (None, Some(_right)) => break self.right.nth(n).map(T::right),
+                (Some(left), Some(right)) => {
+                    let (left, right, _) = (self.cmp_fn)(&left, &right).merge(left, right);
+                    if let Some(left) = left {
+                        self.left.put_back(left);
+                    }
+                    if let Some(right) = right {
+                        self.right.put_back(right);
+                    }
+                }
+            }
+        }
+    }
+}