Method next_back

cranelift/bforest/src/map.rs:779–821

(&mut self)

    C: Comparator<K>,
{
    fn next_back(&mut self) -> Option<Self::Item> {
        let old_direction = mem::replace(&mut self.direction, Direction::NextBack);

        let key_val = (|| {
            if old_direction == Direction::NextBack {
                self.cursor.prev()
            } else {
                match self.end {
                    Bound::Included(k) => match self.cursor.goto(k) {
                        Some(_) => Some((self.cursor.key()?, self.cursor.value()?)),
                        None => self.cursor.prev(),
                    },
                    Bound::Excluded(k) => {
                        self.cursor.goto(k);
                        if self
                            .cursor
                            .key()
                            .is_some_and(|key| self.cursor.comp.cmp(k, key).is_eq())
                        {
                            self.cursor.prev()
                        } else {
                            Some((self.cursor.key()?, self.cursor.value()?))
                        }
                    }
                    Bound::Unbounded => {
                        self.cursor.goto_end();
                        self.cursor.prev()
                    }
                }
            }
        })();

        match key_val {
            Some((key, val)) if self.is_in_bounds(key) => {
                self.end = Bound::Excluded(key);
                Some((key, val))
            }
            _ => {
                self.cursor.goto_end();
                None
            }
        }
    }
}

impl<'a, K, V, C> MapRange<'a, K, V, C>