The author helpfully explains the code by way of un-optimizing it to something readable: http://pastes.archbsd.net/graphitemaster/hashtable_explinati...

see why couldn't the code be written this way by default! then they would've been understandable from the beginning!

That un-optimized version also helpfully lacks the buffer overflow bug.

The "clockwise spiral rule" is wrong in general, as Linus Torvalds helpfully explains here:

http://webcache.googleusercontent.com/search?q=cache:V51nbJE...

(Cache link since original post is 500.)

or http://cdecl.org