use core::ops::{Index, Range};
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>,
{
new_range
.rev()
.zip(old_range.rev())
.take_while(|x| new[x.0] == old[x.1])
.count()
}
#[cfg(test)]
mod tests {
use pretty_assertions::assert_eq;
use super::*;
#[test]
fn test_common_suffix_len() {
assert_eq!(
common_suffix_len("".as_bytes(), 0..0, "".as_bytes(), 0..0),
0
);
assert_eq!(
common_suffix_len("1234".as_bytes(), 0..4, "X0001234".as_bytes(), 0..8),
4
);
assert_eq!(
common_suffix_len("1234".as_bytes(), 0..4, "Xxxx".as_bytes(), 0..4),
0
);
assert_eq!(
common_suffix_len("1234".as_bytes(), 2..4, "01234".as_bytes(), 2..5),
2
);
}
}