__slots__ = ["maxval", "midval"]
def __init__(self, underlying, bits):
Adapter.__init__(self, underlying)
self.maxval = 1 << bits
self.midval = self.maxval >> 1
def encode(self, obj, ctx):
return obj + self.maxval if obj < 0 else obj
def decode(self, obj, ctx):
return obj - self.maxval if obj & self.midval else obj
uint24b = Adapter(Sequence(uint8, uint16b),
decode=lambda obj, _: (obj[0] << 16) | obj[1],
encode=lambda obj, _: (obj >> 16, obj & 0xffff))
sint24b = TwosComplement(uint24b, 24)
uint24l = Adapter(uint24b,
decode=lambda obj, _:
((obj >> 16) & 0xff) | (obj & 0xff00) | ((obj & 0xff) << 16),
encode=lambda obj, _:
((obj >> 16) & 0xff) | (obj & 0xff00) | ((obj & 0xff) << 16))
sint24l = TwosComplement(uint24l, 24)
class MaskedInteger(Adapter):
r"""
>>> m = MaskedInteger(uint16l,
... bottom4 = (0, 4),
... upper12 = (4, 12),
