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import itertools
import operator
class EnumValueBase(object):
# XXX: Horrible?
def __int__(self):
return self.value
def __str__(self):
return self.name
def __or__(self, enumValue):
# XXX: Don't support mixing enum types.
return EnumValueGroup(
[self, enumValue],
' | ',
operator.or_)
def __and__(self, enumValue):
# XXX: Don't support mixing enum types.
return EnumValueGroup(
[self, enumValue],
' & ',
operator.and_)
def __xor__(self, enumValue):
# XXX: Don't support mixing enum types.
return EnumValueGroup(
[self, enumValue],
' ^ ',
operator.xor)
class EnumValue(EnumValueBase):
def __init__(self, name, value):
self.name = name
self.value = value
def __repr__(self):
return '<%s %s: %r>' % (
type(self).__name__, self.name, self.value)
def __contains__(self, enumValue):
if isinstance(enumValue, EnumValue):
return self is enumValue
return enumValue == self.value
class EnumValueGroup(EnumValueBase):
def __init__(self, enumValues, opName, op):
self.enumValues = enumValues
self.opName = opName
self.op = op
def __repr__(self):
return '<%s %r: %r>' % (
type(self).__name__, self.opName.strip(), self.enumValues)
def __contains__(self, enumValue):
for e in self.enumValues:
if enumValue in e:
return True
return False
def value(self):
values = (e.value for e in self.enumValues)
return reduce(self.op, values)
value = property(value)
def name(self):
names = (e.name for e in self.enumValues)
return '(%s)' % (self.opName.join(names),)
name = property(name)
class EnumMetaclass(type):
def __init__(cls, name, bases, attrs):
super(EnumMetaclass, cls).__init__(name, bases, attrs)
cls._reverseLookup = {}
for basecls in bases:
cls._reverseLookup.update(getattr(basecls, '_reverseLookup', {}))
for attrname, attrvalue in attrs.iteritems():
# XXX: Maybe not the best way of determining the enumeration values.
if attrname.isupper():
enumValue = EnumValue('%s.%s' % (cls.__name__, attrname), attrvalue)
if attrvalue in cls._reverseLookup:
raise ValueError(
'Duplicate enumeration value %r (%s) in %r' % (
attrvalue, attrname, cls))
cls._reverseLookup[attrvalue] = enumValue
setattr(cls, attrname, enumValue)
def __repr__(cls):
return '<%s %r>' % (cls.__name__, sorted(cls._reverseLookup.values(), key=int))
def __contains__(cls, enumValue):
if not isinstance(enumValue, EnumValue):
return enumValue in cls._reverseLookup
for v in cls._reverseLookup.itervalues():
if v is enumValue:
return True
return False
class Enum(object):
__metaclass__ = EnumMetaclass
def fromValue(cls, value):
result = cls._reverseLookup.get(value)
if result is None:
target = value
for v, enumValue in sorted(cls._reverseLookup.iteritems(), reverse=True):
if target - v < 0:
continue
if result is None:
result = enumValue
else:
result |= enumValue
target -= v
if target != 0:
raise ValueError('Impossible value: %r' % (value,))
return result
fromValue = classmethod(fromValue)
class SomeFlags(Enum):
FOO = 0x01
BAR = 0x02
QUUX = 0x04
class MoreFlags(SomeFlags):
BAZ = 0x08
class Words(Enum):
AYE = 'a'
BEE = 'b'
print SomeFlags.FOO
print SomeFlags.BAR
both = SomeFlags.FOO | SomeFlags.BAR
print repr(both), both, both.value
print SomeFlags.QUUX in both, SomeFlags.FOO in both
all = both & SomeFlags.QUUX
print repr(all), all, all.value
some = both ^ SomeFlags.QUUX
print repr(some), some, some.value
print SomeFlags.fromValue(2), SomeFlags.fromValue(3)
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