Lib/ipaddress.py (part 2)

Source:

cpython 3.14 @ ab2d84fe1023/Lib/ipaddress.py ↗

This annotation covers IPv6 and network operations. See lib_ipaddress_detail for IPv4Address, ip_address(), ip_network(), and address/network basics.

Map

Lines	Symbol	Role
1-100	IPv6Address.__init__	Parse IPv6 string, bytes, or int
101-250	IPv6Address properties	compressed, exploded, ipv4_mapped, scope_id
251-400	IPv6Network	Network with prefix length; hosts(), subnets()
401-550	Containment	address in network — __contains__
551-700	supernet / subnets	Parent and child networks
701-900	collapse_addresses	Merge overlapping/adjacent networks
901-1100	Address comparison	__eq__, __lt__ based on packed integer
1101-2200	summarize_address_range	Minimal set of networks covering a range

Reading

IPv6Address.__init__

# CPython: Lib/ipaddress.py:1680 IPv6Address
class IPv6Address(_BaseAddress):
    def __init__(self, address):
        if isinstance(address, bytes):
            # 16-byte packed representation
            self._check_packed_address(address, 16)
            bvs = _compat_from_bytes(address, 'big')
        elif isinstance(address, int):
            self._check_int_address(address)
            bvs = address
        else:
            # String: parse with _check_ip_addresses
            addr_str = str(address)
            if '%' in addr_str:
                addr_str, self._scope_id = addr_str.split('%', 1)
            bvs = self._ip_int_from_string(addr_str)
        self._ip = bvs

IPv6Address.compressed

# CPython: Lib/ipaddress.py:1820 compressed
@property
def compressed(self):
    """Compress consecutive zero groups: 2001:db8::1."""
    return _compress_hextets(self._string_from_ip_int(self._ip))

RFC 5952 canonical compression: the longest run of consecutive zero groups is replaced with ::.

IPv6Network.__contains__

# CPython: Lib/ipaddress.py:2030 _BaseNetwork.__contains__
def __contains__(self, other):
    if not isinstance(other, _IPAddressBase):
        raise TypeError('%r is not an IP address or network' % other)
    if isinstance(other, _BaseNetwork):
        return (other.network_address >= self.network_address and
                other.broadcast_address <= self.broadcast_address)
    return (int(other) & int(self.netmask)) == int(self.network_address)

collapse_addresses

# CPython: Lib/ipaddress.py:2200 collapse_addresses
def collapse_addresses(addresses):
    """Return minimal set of networks that cover all input addresses/networks."""
    # Sort by (network_address, prefix_length desc)
    # Sweep: if current is a subnet of previous, skip; else emit previous
    addrs = sorted(set(addresses), key=lambda x: (x.network_address, x.prefixlen))
    i = addrs[0]
    for j in addrs[1:]:
        if i.supernet_of(j):
            continue  # j is contained in i
        elif i.network_address + (i.num_addresses - 1) + 1 == j.network_address \
             and i.prefixlen == j.prefixlen:
            i = i.supernet()  # merge adjacent same-size networks
        else:
            yield i
            i = j
    yield i

gopy notes

ipaddress is pure Python. IPv6Address._ip is a Python int (128-bit). IPv6Network.__contains__ uses int(other) & int(self.netmask) which uses Python's arbitrary-precision arithmetic backed by gopy's objects/longobject.go.