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 an unsigned integer ostensibly representing a checksum.
decodePacket -- the ordered list of bytes to be converted into an unsigned integer.
Note that no checksum validation is performed here.
"""
return utilities.bytesToUnsignedInteger(decodePacket)
def _decode_(self, decodePacket):
"""Decodes the provided packet snippet into a dictionary of bitfield names and values.
decodePacket -- the ordered list of bytes to be converted into a dictionary.
"""
inputValue = utilities.bytesToUnsignedInteger(decodePacket)
decodeDictionary = {} #stores bitName:bitValue pairs
for bitPosition in self.bitPositionBitNameDictionary: #iterate over all bit positions in bitfield definition
bitName = self.bitPositionBitNameDictionary[bitPosition] #grab bit name
bitValue = bool(inputValue&(1<<bitPosition)) #test if bit in inputValue is set
decodeDictionary.update({bitName:bitValue}) #update the decode dictionary
return decodeDictionary
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
def _decode_(self, decodePacket):
"""Decodes the provided packet snippet into an unsigned integer.
decodePacket -- the ordered list of bytes to be converted into an unsigned integer.
"""
return utilities.bytesToUnsignedInteger(decodePacket)