def _decode_(self, decodePacket):
"""Decodes the provided packet snippet into a signed integer of length self.size.
decodePacket -- the ordered list of bytes to be converted into an unsigned integer.
"""
twosComplementInteger = utilities.bytesToUnsignedInteger(decodePacket)
return utilities.twosComplementToSignedInteger(twosComplementInteger, self.bitSize)
def _decode_(self, decodePacket):
"""Decodes the provided packet snippet into a fixed point signed decimal.
decodePacket -- the ordered list of bytes to be converted into a fixed point decimal.
"""
twosComplementRepresentation = utilities.bytesToUnsignedInteger(decodePacket)
twosComplementRepresentation = twosComplementRepresentation&(2**(self.bitSize) - 1) #mask off any unwanted bits
if self.integerBits > 0: #signed value
signedInteger = utilities.twosComplementToSignedInteger(twosComplementRepresentation, self.bitSize)
else: #no integer bits, unsigned value
signedInteger = twosComplementRepresentation
bitShiftedValue = float(signedInteger)/(2**self.fractionalBits)
return bitShiftedValue