Link truncation can break validation

The link truncation function works on an entitized version of the URL, which can occasionally cause an entity to get cut apart in an invalid way.  For example:

http://www.example.com/form.php?id=7&am … mp;where=4

http://validator.w3.org/check?uri=referer

I know this code is kind of quick and dirty ("Ok, not very pretty :-)") and that it's really a minor issue, but shouldn't it be easy to fix by de-entitizing the displayed URI before truncation and then re-entitizing it?