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Simplify range comparison code

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Reword the `Kind` type so that the `cmp` function is simpler.
This commit is contained in:
Michael Wright 2021-11-09 05:44:02 +02:00
parent 949b25981c
commit f829523340
1 changed files with 25 additions and 42 deletions
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67
clippy_lints/src/matches.rs
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@ -1698,75 +1698,58 @@ pub fn overlapping<T>(ranges: &[SpannedRange<T>]) -> Option<(&SpannedRange<T>, &
where
T: Copy + Ord,
{
#[derive(Copy, Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
enum BoundKind {
EndExcluded,
Start,
EndIncluded,
}
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
enum Kind<'a, T> {
Start(T, &'a SpannedRange<T>),
End(EndBound<T>, &'a SpannedRange<T>),
}
struct RangeBound<'a, T>(T, BoundKind, &'a SpannedRange<T>);
impl<'a, T: Copy> Kind<'a, T> {
fn value(self) -> T {
match self {
Kind::Start(t, _) | Kind::End(EndBound::Included(t) | EndBound::Excluded(t), _) => t,
}
}
}
impl<'a, T: Copy + Ord> PartialOrd for Kind<'a, T> {
impl<'a, T: Copy + Ord> PartialOrd for RangeBound<'a, T> {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl<'a, T: Copy + Ord> Ord for Kind<'a, T> {
fn cmp(&self, other: &Self) -> Ordering {
match self.value().cmp(&other.value()) {
Ordering::Equal => match (self, other) {
// End excluded before start and end included
(Kind::End(EndBound::Excluded(_), _), Kind::Start(..) | Kind::End(EndBound::Included(_), _)) => {
Ordering::Less
},
(Kind::Start(..) | Kind::End(EndBound::Included(_), _), Kind::End(EndBound::Excluded(_), _)) => {
Ordering::Greater
},
// Start before end included
(Kind::Start(..), Kind::End(EndBound::Included(_), _)) => Ordering::Less,
(Kind::End(EndBound::Included(_), _), Kind::Start(..)) => Ordering::Greater,
_ => Ordering::Equal,
},
other => other,
}
impl<'a, T: Copy + Ord> Ord for RangeBound<'a, T> {
fn cmp(&self, RangeBound(other_value, other_kind, _): &Self) -> Ordering {
let RangeBound(self_value, self_kind, _) = *self;
(self_value, self_kind).cmp(&(*other_value, *other_kind))
}
}
let mut values = Vec::with_capacity(2 * ranges.len());
for r in ranges {
values.push(Kind::Start(r.node.0, r));
values.push(Kind::End(r.node.1, r));
for r @ SpannedRange { node: (start, end), .. } in ranges {
values.push(RangeBound(*start, BoundKind::Start, r));
values.push(match end {
EndBound::Excluded(val) => RangeBound(*val, BoundKind::EndExcluded, r),
EndBound::Included(val) => RangeBound(*val, BoundKind::EndIncluded, r),
});
}
values.sort();
let mut started = vec![];
for value in values {
match value {
Kind::Start(_, r) => started.push(r),
Kind::End(_, er) => {
for RangeBound(_, kind, r) in values {
match kind {
BoundKind::Start => started.push(r),
BoundKind::EndExcluded | BoundKind::EndIncluded => {
let mut overlap = None;
while let Some(sr) = started.pop() {
if sr == er {
if sr == r {
break;
}
overlap = Some(sr);
}
if let Some(sr) = overlap {
return Some((er, sr));
return Some((r, sr));
}
},
}