def dissectResponse(frame):
buf = utils.makeBuffer(frame)
arr = utils.makeArray(buf)
crc = Crc(0xffff)
actualValue = 0
sd = arr[defs.START_DELIMITER]
length = arr[defs.LENGTH]
da = arr[defs.DESTINATION_ADRESS]
sa = arr[defs.SOURCE_ADDRESS]
crc.update(length)
crc.update(da)
crc.update(sa)
dissectingState = APDU_HEADER0
numberOfDataBytes = 0
byteCount = 0
result = []
if not (length == len(arr) - 4):
raise FramingError("Frame length doesn't match length byte.")
assert(frame == arr)
for idx in range(defs.PDU_START, length + 2):
ch = arr[idx]
crc.update(ch)
if dissectingState == APDU_HEADER0:
klass = ch & 0x0f
if klass not in defs.SUPPORTED_CLASSES:
# Well, to be precise, these classes are not really documented by the GENIBus spec...
raise ADPUClassNotSupportedError("APDU class '%u' not supported by GeniControl." % klass)
dissectingState = APDU_HEADER1
data = []
elif dissectingState == APDU_HEADER1:
numberOfDataBytes = ch & 0x3F
opAck = (ch & 0xC0) >> 6
byteCount = numberOfDataBytes
if byteCount:
dissectingState = APDU_DATA
else:
dissectingState = APDU_HEADER0
result.append(APDU(klass, opAck, data))
elif dissectingState == APDU_DATA:
byteCount -= 1
if byteCount <= 0:
dissectingState = APDU_HEADER0
result.append(APDU(klass, opAck, data))
else:
data.append(ch)
frameCrc = utils.makeWord(arr[defs.CRC_HIGH], arr[defs.CRC_LOW])
if crc.get() != frameCrc:
raise CrcError("Frame CRC doesn't match calculated CRC.")
return DissectionResult(sd, da, sa, result)
def expectedCrc(frame):
return utils.makeWord(frame[defs.CRC_HIGH], frame[defs.CRC_LOW])
