Used IP addresses

Anyone got some C code that loops over all used IP addresses?  Can you come up with any special optimizations?  (I need to handle them in the "%u.%u.%u.%u"-form; computations are independant and can be run in parallel)

>>40
This problem was caused by the popularity of IBM's System/360 architecture, which had standardized on 8 bits per byte. This led to IP networking standards using these as a basic component in designing the structure of protocols.

Some computers at the time had 9 bits in a byte, and 36-bit words. Just think if our IP addresses were made up of four nonets instead - we'd have 68 billion addresses available and all this talk of IPv6 migration wouldn't be happening!