util.py 文件源码

def _get_available_subnets(prefix_or_prefixes, used_prefixes):
    """Get available prefixes within a list of CIDR addresses, based on what
    prefixes are in use. E.g. this is `get_available_subnets`, but with
    explicit dependency injection.

    Args:
        prefix_or_prefixes: a single or a list of prefixes ("10.0.0.0/8") or
                          IPy.IP objects
        used_prefixes: prefixes that are in use

    Returns:
           An iterable IPy.IPSet of available addresses within prefix_or_prefixes

    """
    if not isinstance(prefix_or_prefixes, list):
        prefix_or_prefixes = [prefix_or_prefixes]
    base_prefixes = [str(prefix) for prefix in prefix_or_prefixes]
    acc = IPSet([IP(prefix) for prefix in prefix_or_prefixes])
    used_prefixes = IPSet([IP(used) for used in used_prefixes])
    # remove used prefixes
    acc.discard(used_prefixes)
    # filter away original prefixes
    return sorted([ip for ip in acc if str(ip) not in base_prefixes])