Merge crates

src/utils/common_suffix_len.rs

@@ -0,0 +1,48 @@
+use core::ops::{Index, Range};
+
+/// Given two lookups and ranges calculates the length of common suffix.
+/// Copied from <https://github.com/mitsuhiko/similar/blob/7e15c44de11a1cd61e1149189929e189ef977fd8/src/algorithms/utils.rs>
+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
+        );
+    }
+}