def get_payload(self):
payload_bits = BitArray(length=8 * 8) # 8 Byte Message
field_index = 0
for fieldConfig in sorted(self.field_config['Fields'],
key=lambda f: f['Order']):
logger.debug(fieldConfig)
length = fieldConfig['BitLength']
offset = fieldConfig['BitOffset']
signed = fieldConfig['Signed']
start = fieldConfig['BitStart']
if fieldConfig['BitStart'] == 0:
if length < 8:
position = offset + 8 - length
else:
position = offset
else:
position = offset - start
logger.debug("Field {name} starts at: {position}".format(
name=fieldConfig['Name'], position=position))
logger.debug("Field {name} length is: {length}".format(
name=fieldConfig['Name'], length=length))
try:
resolution = fieldConfig['Resolution']
except KeyError:
resolution = None
value = self.field_data[field_index]
logger.debug("Value before conversion is: %s" % value)
if value is not None:
if resolution is not None:
value = int(float(value) / float(resolution))
if not signed:
logger.debug("Field {name} is unsigned".format(
name=fieldConfig['Name']))
value = Bits(uint=value, length=length)
else:
logger.debug("Field {name} is signed".format(
name=fieldConfig['Name']))
value = Bits(int=value, length=length)
else:
value = BitArray(length=length)
value.invert()
if signed:
value[0] = False
value = Bits(value)
logger.debug("Field {name} value post conversion: {value}".format(
name=fieldConfig['Name'], value=value))
if length % 8 == 0:
value = Bits(bytes=reversed(value.bytes))
payload_bits.overwrite(value, position)
field_index += 1
pad = 8 * 8 - len(payload_bits)
if (pad > 0):
payload_bits.append(Bits(length=pad))
data = list(payload_bits.bytes)
logger.debug("Payload data is: %s" % data)
return data
