Also avoid potential heap overwrites in there.
Sadly I have no examples for OCT files and it doesn't seem like a very common format as I couldn't even find any examples online.
So just assuming my changes work.
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6291 dfc29bdd-3216-0410-991c-e03cc46cb475