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Make RangeMut::next_unchecked() output a mutable key reference

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This commit is contained in:
Charles Gleason 2019-11-21 22:09:10 -05:00
parent a916ac22b9
commit 293cdf7ac5
1 changed files with 15 additions and 7 deletions
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22
src/liballoc/collections/btree/map.rs
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@ -1328,7 +1328,10 @@ impl<'a, K: 'a, V: 'a> Iterator for IterMut<'a, K, V> {
None
} else {
self.length -= 1;
unsafe { Some(self.range.next_unchecked()) }
unsafe {
let (k, v) = self.range.next_unchecked();
Some((k, v)) // coerce k from `&mut K` to `&K`
}
}
}
@ -1707,7 +1710,14 @@ impl<'a, K, V> Iterator for RangeMut<'a, K, V> {
type Item = (&'a K, &'a mut V);
fn next(&mut self) -> Option<(&'a K, &'a mut V)> {
if self.front == self.back { None } else { unsafe { Some(self.next_unchecked()) } }
if self.front == self.back {
None
} else {
unsafe {
let (k, v) = self.next_unchecked();
Some((k, v)) // coerce k from `&mut K` to `&K`
}
}
}
fn last(mut self) -> Option<(&'a K, &'a mut V)> {
@ -1716,7 +1726,7 @@ impl<'a, K, V> Iterator for RangeMut<'a, K, V> {
}
impl<'a, K, V> RangeMut<'a, K, V> {
unsafe fn next_unchecked(&mut self) -> (&'a K, &'a mut V) {
unsafe fn next_unchecked(&mut self) -> (&'a mut K, &'a mut V) {
let handle = ptr::read(&self.front);
let mut cur_handle = match handle.right_kv() {
@ -1724,8 +1734,7 @@ impl<'a, K, V> RangeMut<'a, K, V> {
self.front = ptr::read(&kv).right_edge();
// Doing the descend invalidates the references returned by `into_kv_mut`,
// so we have to do this last.
let (k, v) = kv.into_kv_mut();
return (k, v); // coerce k from `&mut K` to `&K`
return kv.into_kv_mut();
}
Err(last_edge) => {
let next_level = last_edge.into_node().ascend().ok();
@ -1739,8 +1748,7 @@ impl<'a, K, V> RangeMut<'a, K, V> {
self.front = first_leaf_edge(ptr::read(&kv).right_edge().descend());
// Doing the descend invalidates the references returned by `into_kv_mut`,
// so we have to do this last.
let (k, v) = kv.into_kv_mut();
return (k, v); // coerce k from `&mut K` to `&K`
return kv.into_kv_mut();
}
Err(last_edge) => {
let next_level = last_edge.into_node().ascend().ok();