Implement PEP 3144 (the ipaddress module)

Lib/ipaddress.py

 # Copyright 2007 Google Inc.
 #  Licensed to PSF under a Contributor Agreement.
 
 """A fast, lightweight IPv4/IPv6 manipulation library in Python.
 
 This library is used to create/poke/manipulate IPv4 and IPv6 addresses
 and networks.
 
 """
 
@@ skipping 1972 matching lines @@
         _BaseV6.__init__(self, address)
         _BaseNetwork.__init__(self, address)
 
         # Efficient constructor from integer.
         if isinstance(address, int):
             if address < 0 or address > self._ALL_ONES:
                 raise AddressValueError(address)
             self.network_address = IPv6Address(address)
             self._prefixlen = self._max_prefixlen
             self.netmask = IPv6Address(self._ALL_ONES)
-            if strict:
-                if (IPv6Address(int(self.network_address) &
-                                int(self.netmask)) != self.network_address):
-                    raise ValueError('%s has host bits set' % str(self))
             self.network_address = IPv6Address(int(self.network_address) &
                                                int(self.netmask))

[Nick Coghlan, 2012/06/08 14:50:18]

The second assignment of network_address can go away, too.

             return
 
         # Constructing from a packed address
         if isinstance(address, bytes) and len(address) == 16:
             tmp = struct.unpack('!QQ', address)
             self.network_address = IPv6Address((tmp[0] << 64) | tmp[1])
             self._prefixlen = self._max_prefixlen
             self.netmask = IPv6Address(self._ALL_ONES)
-            if strict:
-                if (IPv6Address(int(self.network_address) &
-                                int(self.netmask)) != self.network_address):
-                    raise ValueError('%s has host bits set' % str(self))
-                self.network_address = IPv6Address(int(self.network_address) &
-                                                   int(self.netmask))
-                return
+            self.network_address = IPv6Address(int(self.network_address) &

[Nick Coghlan, 2012/06/08 14:50:18]

As above - with the netmask set to all ones, no need to reassign the network
address to a masked version.

+                                                int(self.netmask))
+            return
 
         # Assume input argument to be string or any object representation
         # which converts into a formatted IP prefix string.
         addr = str(address).split('/')
 
         if len(addr) > 2:
             raise AddressValueError(address)
 
         self.network_address = IPv6Address(self._ip_int_from_string(addr[0]))
 
@@ skipping 25 matching lines @@
         Returns:
             A boolean, True if the prefix represents a valid IPv6
             netmask.
 
         """
         try:
             prefixlen = int(prefixlen)
         except ValueError:
             return False
         return 0 <= prefixlen <= self._max_prefixlen