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class Bit(object):
"""
Represents a single Bit.
"""
def __init__(self, number, is_set=True):
self.number = number
self.is_set = bool(is_set)
self.mask = 2 ** int(number)
if not self.is_set:
self.mask = ~self.mask
def __repr__(self):
return '<%s: number=%d, is_set=%s>' % (self.__class__.__name__, self.number, self.is_set)
# def __str__(self):
# if self.is_set:
# return 'Yes'
# return 'No'
def __int__(self):
return self.mask
def __nonzero__(self):
return self.is_set
def __eq__(self, value):
if isinstance(value, Bit):
return value.number == self.number and value.is_set == self.is_set
elif isinstance(value, bool):
return value == self.is_set
elif isinstance(value, int):
return value == self.mask
return value == self.is_set
def __ne__(self, value):
return not self == value
def __coerce__(self, value):
return (self.is_set, bool(value))
def __invert__(self):
return self.__class__(self.number, not self.is_set)
def __and__(self, value):
if isinstance(value, Bit):
value = value.mask
return value & self.mask
def __rand__(self, value):
if isinstance(value, Bit):
value = value.mask
return self.mask & value
def __or__(self, value):
if isinstance(value, Bit):
value = value.mask
return value | self.mask
def __ror__(self, value):
if isinstance(value, Bit):
value = value.mask
return self.mask | value
def __lshift__(self, value):
if isinstance(value, Bit):
value = value.mask
return value << self.mask
def __rlshift__(self, value):
if isinstance(value, Bit):
value = value.mask
return self.mask << value
def __rshift__(self, value):
if isinstance(value, Bit):
value = value.mask
return value >> self.mask
def __rrshift__(self, value):
if isinstance(value, Bit):
value = value.mask
return self.mask >> value
def __xor__(self, value):
if isinstance(value, Bit):
value = value.mask
return value ^ self.mask
def __rxor__(self, value):
if isinstance(value, Bit):
value = value.mask
return self.mask ^ value
def __sentry__(self):
return repr(self)
def prepare(self, evaluator, query, allow_joins):
return self
def evaluate(self, evaluator, qn, connection):
return self.mask, []
class BitHandler(object):
"""
Represents an array of bits, each as a ``Bit`` object.
"""
def __init__(self, value, keys):
# TODO: change to bitarray?
if value:
self._value = int(value)
else:
self._value = 0
self._keys = keys
def __eq__(self, other):
if not isinstance(other, BitHandler):
return False
return self._value == other._value
def __repr__(self):
return '<%s: %s>' % (self.__class__.__name__, ', '.join('%s=%s' % (k, self.get_bit(n).is_set) for n, k in enumerate(self._keys)),)
def __str__(self):
return str(self._value)
def __int__(self):
return self._value
def __nonzero__(self):
return bool(self._value)
def __and__(self, value):
return BitHandler(self._value & int(value), self._keys)
def __or__(self, value):
return BitHandler(self._value | int(value), self._keys)
def __add__(self, value):
return BitHandler(self._value + int(value), self._keys)
def __sub__(self, value):
return BitHandler(self._value - int(value), self._keys)
def __lshift__(self, value):
return BitHandler(self._value << int(value), self._keys)
def __rshift__(self, value):
return BitHandler(self._value >> int(value), self._keys)
def __xor__(self, value):
return BitHandler(self._value ^ int(value), self._keys)
def __contains__(self, key):
bit_number = self._keys.index(key)
return bool(self.get_bit(bit_number))
def __getattr__(self, key):
if key.startswith('_'):
return object.__getattribute__(self, key)
if key not in self._keys:
raise AttributeError('%s is not a valid flag' % key)
return self.get_bit(self._keys.index(key))
def __setattr__(self, key, value):
if key.startswith('_'):
return object.__setattr__(self, key, value)
if key not in self._keys:
raise AttributeError('%s is not a valid flag' % key)
self.set_bit(self._keys.index(key), value)
def __iter__(self):
return self.iteritems()
def __sentry__(self):
return repr(self)
def _get_mask(self):
return self._value
mask = property(_get_mask)
def prepare(self, evaluator, query, allow_joins):
return self
def evaluate(self, evaluator, qn, connection):
return self.mask, []
def get_bit(self, bit_number):
mask = 2 ** int(bit_number)
return Bit(bit_number, self._value & mask != 0)
def set_bit(self, bit_number, true_or_false):
mask = 2 ** int(bit_number)
if true_or_false:
self._value |= mask
else:
self._value &= (~mask)
return Bit(bit_number, self._value & mask != 0)
def keys(self):
return self._keys
def iterkeys(self):
return iter(self._keys)
def items(self):
return list(self.iteritems())
def iteritems(self):
for k in self._keys:
yield (k, getattr(self, k).is_set)
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