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use core::ops::{Bound, Range, RangeBounds};
pub(crate) fn third<A, B, C>(t: (A, B, C)) -> C {
t.2
}
pub(crate) fn simplify_range<R>(range: R, len: usize) -> Range<usize>
where
R: RangeBounds<usize>,
{
let start = match range.start_bound() {
Bound::Unbounded => 0,
Bound::Included(&i) if i <= len => i,
Bound::Excluded(&i) if i < len => i + 1,
bound => panic!("range start {:?} should be <= length {}", bound, len),
};
let end = match range.end_bound() {
Bound::Unbounded => len,
Bound::Excluded(&i) if i <= len => i,
Bound::Included(&i) if i < len => i + 1,
bound => panic!("range end {:?} should be <= length {}", bound, len),
};
if start > end {
panic!(
"range start {:?} should be <= range end {:?}",
range.start_bound(),
range.end_bound()
);
}
start..end
}
pub(crate) fn try_simplify_range<R>(range: R, len: usize) -> Option<Range<usize>>
where
R: RangeBounds<usize>,
{
let start = match range.start_bound() {
Bound::Unbounded => 0,
Bound::Included(&i) if i <= len => i,
Bound::Excluded(&i) if i < len => i + 1,
_ => return None,
};
let end = match range.end_bound() {
Bound::Unbounded => len,
Bound::Excluded(&i) if i <= len => i,
Bound::Included(&i) if i < len => i + 1,
_ => return None,
};
if start > end {
return None;
}
Some(start..end)
}