"""Drop-in replacement for collections.OrderedDict by Raymond Hettinger
http://code.activestate.com/recipes/576693/
"""
from UserDict import DictMixin
class OrderedDict(dict, DictMixin):
def __init__(self, *args, **kwds):
if len(args) > 1:
raise TypeError('expected at most 1 arguments, got %d' % len(args))
try:
self.__end
except AttributeError:
self.clear()
self.update(*args, **kwds)
def clear(self):
self.__end = end = []
end += [None, end, end] # sentinel node for doubly linked list
self.__map = {} # key --> [key, prev, next]
dict.clear(self)
def __setitem__(self, key, value):
if key not in self:
end = self.__end
curr = end[1]
curr[2] = end[1] = self.__map[key] = [key, curr, end]
dict.__setitem__(self, key, value)
def __delitem__(self, key):
dict.__delitem__(self, key)
key, prev, next = self.__map.pop(key)
prev[2] = next
next[1] = prev
def __iter__(self):
end = self.__end
curr = end[2]
while curr is not end:
yield curr[0]
curr = curr[2]
def __reversed__(self):
end = self.__end
curr = end[1]
while curr is not end:
yield curr[0]
curr = curr[1]
def popitem(self, last=True):
if not self:
raise KeyError('dictionary is empty')
key = reversed(self).next() if last else iter(self).next()
value = self.pop(key)
return key, value
def __reduce__(self):
items = [[k, self[k]] for k in self]
tmp = self.__map, self.__end
del self.__map, self.__end
inst_dict = vars(self).copy()
self.__map, self.__end = tmp
if inst_dict:
return (self.__class__, (items,), inst_dict)
return self.__class__, (items,)
def keys(self):
return list(self)
setdefault = DictMixin.setdefault
update = DictMixin.update
pop = DictMixin.pop
values = DictMixin.values
items = DictMixin.items
iterkeys = DictMixin.iterkeys
itervalues = DictMixin.itervalues
iteritems = DictMixin.iteritems
def __repr__(self):
if not self:
return '%s()' % (self.__class__.__name__,)
return '%s(%r)' % (self.__class__.__name__, self.items())
def copy(self):
return self.__class__(self)
@classmethod
def fromkeys(cls, iterable, value=None):
d = cls()
for key in iterable:
d[key] = value
return d
def __eq__(self, other):
if isinstance(other, OrderedDict):
return len(self)==len(other) and \
all(p==q for p, q in zip(self.items(), other.items()))
return dict.__eq__(self, other)
def __ne__(self, other):
return not self == other
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