--- /dev/null
+# Copyright (C) 2003-2007, 2009, 2010 Nominum, Inc.
+#
+# Permission to use, copy, modify, and distribute this software and its
+# documentation for any purpose with or without fee is hereby granted,
+# provided that the above copyright notice and this permission notice
+# appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
+# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+"""A simple Set class."""
+
+class Set(object):
+ """A simple set class.
+
+ Sets are not in Python until 2.3, and rdata are not immutable so
+ we cannot use sets.Set anyway. This class implements subset of
+ the 2.3 Set interface using a list as the container.
+
+ @ivar items: A list of the items which are in the set
+ @type items: list"""
+
+ __slots__ = ['items']
+
+ def __init__(self, items=None):
+ """Initialize the set.
+
+ @param items: the initial set of items
+ @type items: any iterable or None
+ """
+
+ self.items = []
+ if not items is None:
+ for item in items:
+ self.add(item)
+
+ def __repr__(self):
+ return "dns.simpleset.Set(%s)" % repr(self.items)
+
+ def add(self, item):
+ """Add an item to the set."""
+ if not item in self.items:
+ self.items.append(item)
+
+ def remove(self, item):
+ """Remove an item from the set."""
+ self.items.remove(item)
+
+ def discard(self, item):
+ """Remove an item from the set if present."""
+ try:
+ self.items.remove(item)
+ except ValueError:
+ pass
+
+ def _clone(self):
+ """Make a (shallow) copy of the set.
+
+ There is a 'clone protocol' that subclasses of this class
+ should use. To make a copy, first call your super's _clone()
+ method, and use the object returned as the new instance. Then
+ make shallow copies of the attributes defined in the subclass.
+
+ This protocol allows us to write the set algorithms that
+ return new instances (e.g. union) once, and keep using them in
+ subclasses.
+ """
+
+ cls = self.__class__
+ obj = cls.__new__(cls)
+ obj.items = list(self.items)
+ return obj
+
+ def __copy__(self):
+ """Make a (shallow) copy of the set."""
+ return self._clone()
+
+ def copy(self):
+ """Make a (shallow) copy of the set."""
+ return self._clone()
+
+ def union_update(self, other):
+ """Update the set, adding any elements from other which are not
+ already in the set.
+ @param other: the collection of items with which to update the set
+ @type other: Set object
+ """
+ if not isinstance(other, Set):
+ raise ValueError('other must be a Set instance')
+ if self is other:
+ return
+ for item in other.items:
+ self.add(item)
+
+ def intersection_update(self, other):
+ """Update the set, removing any elements from other which are not
+ in both sets.
+ @param other: the collection of items with which to update the set
+ @type other: Set object
+ """
+ if not isinstance(other, Set):
+ raise ValueError('other must be a Set instance')
+ if self is other:
+ return
+ # we make a copy of the list so that we can remove items from
+ # the list without breaking the iterator.
+ for item in list(self.items):
+ if item not in other.items:
+ self.items.remove(item)
+
+ def difference_update(self, other):
+ """Update the set, removing any elements from other which are in
+ the set.
+ @param other: the collection of items with which to update the set
+ @type other: Set object
+ """
+ if not isinstance(other, Set):
+ raise ValueError('other must be a Set instance')
+ if self is other:
+ self.items = []
+ else:
+ for item in other.items:
+ self.discard(item)
+
+ def union(self, other):
+ """Return a new set which is the union of I{self} and I{other}.
+
+ @param other: the other set
+ @type other: Set object
+ @rtype: the same type as I{self}
+ """
+
+ obj = self._clone()
+ obj.union_update(other)
+ return obj
+
+ def intersection(self, other):
+ """Return a new set which is the intersection of I{self} and I{other}.
+
+ @param other: the other set
+ @type other: Set object
+ @rtype: the same type as I{self}
+ """
+
+ obj = self._clone()
+ obj.intersection_update(other)
+ return obj
+
+ def difference(self, other):
+ """Return a new set which I{self} - I{other}, i.e. the items
+ in I{self} which are not also in I{other}.
+
+ @param other: the other set
+ @type other: Set object
+ @rtype: the same type as I{self}
+ """
+
+ obj = self._clone()
+ obj.difference_update(other)
+ return obj
+
+ def __or__(self, other):
+ return self.union(other)
+
+ def __and__(self, other):
+ return self.intersection(other)
+
+ def __add__(self, other):
+ return self.union(other)
+
+ def __sub__(self, other):
+ return self.difference(other)
+
+ def __ior__(self, other):
+ self.union_update(other)
+ return self
+
+ def __iand__(self, other):
+ self.intersection_update(other)
+ return self
+
+ def __iadd__(self, other):
+ self.union_update(other)
+ return self
+
+ def __isub__(self, other):
+ self.difference_update(other)
+ return self
+
+ def update(self, other):
+ """Update the set, adding any elements from other which are not
+ already in the set.
+ @param other: the collection of items with which to update the set
+ @type other: any iterable type"""
+ for item in other:
+ self.add(item)
+
+ def clear(self):
+ """Make the set empty."""
+ self.items = []
+
+ def __eq__(self, other):
+ # Yes, this is inefficient but the sets we're dealing with are
+ # usually quite small, so it shouldn't hurt too much.
+ for item in self.items:
+ if not item in other.items:
+ return False
+ for item in other.items:
+ if not item in self.items:
+ return False
+ return True
+
+ def __ne__(self, other):
+ return not self.__eq__(other)
+
+ def __len__(self):
+ return len(self.items)
+
+ def __iter__(self):
+ return iter(self.items)
+
+ def __getitem__(self, i):
+ return self.items[i]
+
+ def __delitem__(self, i):
+ del self.items[i]
+
+ def __getslice__(self, i, j):
+ return self.items[i:j]
+
+ def __delslice__(self, i, j):
+ del self.items[i:j]
+
+ def issubset(self, other):
+ """Is I{self} a subset of I{other}?
+
+ @rtype: bool
+ """
+
+ if not isinstance(other, Set):
+ raise ValueError('other must be a Set instance')
+ for item in self.items:
+ if not item in other.items:
+ return False
+ return True
+
+ def issuperset(self, other):
+ """Is I{self} a superset of I{other}?
+
+ @rtype: bool
+ """
+
+ if not isinstance(other, Set):
+ raise ValueError('other must be a Set instance')
+ for item in other.items:
+ if not item in self.items:
+ return False
+ return True
git.samba.org / samba.git / blobdiff