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Diffstat (limited to 'third_party/dnspython/dns/set.py')
| -rw-r--r-- | third_party/dnspython/dns/set.py | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/third_party/dnspython/dns/set.py b/third_party/dnspython/dns/set.py new file mode 100644 index 0000000000..14c76a05c4 --- /dev/null +++ b/third_party/dnspython/dns/set.py @@ -0,0 +1,263 @@ +# Copyright (C) 2003-2007, 2009-2011 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 |