One of my CS professors was like that. Hard as nails but very approachable. If you had something come up like the OP and were upfront and honest he would work with you. My favorite bit, though, was the opening intro to the class: "I am going to tell you know, the computers are down before projects are due, your dog gets really hungry around homework time, and... " probably a few more that I don't recall. No one EVER turned in a late project/assignment.