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Reuse common prefix / common suffix functions

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This commit is contained in:
Armin Ronacher 2021-02-21 19:52:10 +01:00
parent b468bf94e3
commit 1a0aa9b142
3 changed files with 71 additions and 79 deletions
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49
src/algorithms/utils.rs
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@ -93,6 +93,55 @@ where
rv
}
/// Given two lookups and ranges calculates the length of the common prefix.
pub fn common_prefix_len<Old, New>(
old: &Old,
old_range: Range<usize>,
new: &New,
new_range: Range<usize>,
) -> usize
where
Old: Index<usize> + ?Sized,
New: Index<usize> + ?Sized,
New::Output: PartialEq<Old::Output>,
{
if is_empty_range(&old_range) || is_empty_range(&new_range) {
return 0;
}
new_range
.zip(old_range)
.take_while(
#[inline(always)]
|x| new[x.0] == old[x.1],
)
.count()
}
/// Given two lookups and ranges calculates the length of common suffix.
pub fn common_suffix_len<Old, New>(
old: &Old,
old_range: Range<usize>,
new: &New,
new_range: Range<usize>,
) -> usize
where
Old: Index<usize> + ?Sized,
New: Index<usize> + ?Sized,
New::Output: PartialEq<Old::Output>,
{
if is_empty_range(&old_range) || is_empty_range(&new_range) {
return 0;
}
new_range
.rev()
.zip(old_range.rev())
.take_while(
#[inline(always)]
|x| new[x.0] == old[x.1],
)
.count()
}
#[test]
fn test_unique() {
let u = unique(&vec!['a', 'b', 'c', 'd', 'd', 'b'], 0..6)