Calculate free ranges of an IPv4Network

gistfile1.py

    blocked_ips = [ipv4Network[0], ipv4Router]
    ranges = [[ipv4Network[1], ipv4Network[-1]]]
    for ip in blocked_ips:
        index = 0 
        # Find range which includes the ip, i.e. 'start <= ip <= end'
        while (index < len(ranges)) and (not ((ranges[index][0] <= ip) and (ip <= ranges[index][1]))):
            index += 1
        if index == len(ranges):
            # IP address is already excluded
            pass
        else:
            if ip == ranges[index][0]:
                if ip == ranges[index][1]:
                    # The IP is already in an alone range, so just delete this range
                    ranges.pop(index)
                else:
                    # ip < ranges[index][1]
                    ranges[index][0] = ip + 1 
            else:
                # ranges[index][0] < ip
                if ip == ranges[index][1]:
                    # just remove the last ip
                    ranges[index][1] = ip - 1 
                else:
                    # ip is located inside a range, so split this range
                    old_range_end = ranges[index][1]
                    ranges[index][1] = ip - 1 
                    ranges.insert(index + 1, [ip + 1, old_range_end])
    for range in ranges:
        print('    range {0} {1};'.format(range[0], range[1]))