python iterator that returns IP addresses (as strings) for given ip/cidr string

cidrator.py

class cidrator():
    def __init__(self, mask ="192.168.1.1/16", skip255=True, skip0=True):
	self.skip255 = skip255
	self.skip0 = skip0
	
	addr, rng = mask.split("/")
	addr_int = sum((256**(3-i) * int(b)) for i,b in enumerate(addr.split (".")))
	self.start = addr_int & int("0b"+("1"*int(rng)) + "0"*(32-int(rng)),2)
	self.stop = addr_int | int("0b"+("0"*int(rng)) + "1"*(32-int(rng)),2)
	self.current = self.start
	

    def int2ipstr(self, s):
	s = hex(s)[2:]
	return '.'.join(('%s' % int(x,16) for x in (s[i:2+i] for i in xrange(0,8,2))))
	
    def ipstr2int(self, addr):
	return 

    def __iter__(self):
        return self

    def next(self):
        if self.current > self.stop:
            raise StopIteration
        else:
            self.current += 1
	    res = self.int2ipstr(self.current - 1)
	    if res.endswith(".0") and self.skip0:
		res = self.next()
	    if res.endswith('.255') and self.skip255:
		res = self.next()
            return res

Example: for ip in cidrator("172.16.0.0/12"): print ip

It's an iterator, that means you never have to sore the actual list of all IP addresses in memory :)