In short I am looking for something like google-diff-match-patch in PHP.
I have had a look at some similar questions at SO, and also at the algorithm provided here, but all of them fail:
diff("draßen", "da draußen")
should not give
<del>draßen</del> <ins>da draußen</ins>
(which is kind of stupid for my purpose, because I want to compare file names), but (try here)
<ins>da </ins>dra<ins>u</ins>ßen
Is there a code snippet in PHP that does this? Unfortunately, I cannot use (i.e. install) external packages.