def _send(self, packet):
'''
Send a packet over the connection
'''
raw = protocols.to8bit( packet.getPacketRawBytes() )
self._getConnection().write(protocols.toBinaryString(raw))
self._getConnection().flushOutput()
# Log packet hex
self._debug('Packet sent to Serial comms connection: %s' % ','.join(protocols.toHex(raw)))
def recieve(self):
'''Check for and recieve packets waiting in the connection'''
# If nothing in buffer
if not len(self._buffer):
return
# Get protocol
protocol = protocols.getProtocol()
# Check for any complete packets
cache = copy.copy(self._buffer)
try:
packet = protocol.processRecieveBuffer(self._buffer)
except Exception, msg:
raise
logger.error(msg)
logger.error('processRecieveBuffer failed to parse packet from buffer: %s' % join(protocols.toHex(cache)))
self._buffer = []
return
def getPacketHex(self):
'''Return a packet as hex strings'''
packet = self.getEscaped()
return protocols.toHex(packet)
def recieve(self):
'''Check for and recieve packets waiting in the connection'''
conn = self.getConnection()
buffer_size = conn.inWaiting()
# If nothing in serial buffer, and nothing unprocessed
# don't hold up the UI any longer than we have to
if not buffer_size and not len(self._buffer):
return
# If anything new in the buffer, convert to bytes and
# append to what we have left unprocessed
if buffer_size:
buffer = conn.read(buffer_size)
for char in buffer:
self._buffer.append(ord(char))
# Get protocol
protocol = protocols.getProtocol()
# Check for any complete packets
try:
cache = copy.copy(self._buffer)
packet = protocol.processRecieveBuffer(self._buffer)
except Exception, msg:
logger.error(msg)
logger.error('processRecieveBuffer failed to parse packet from buffer: %s' % join(protocols.toHex(cache)))
self._buffer = []
return
def processRecieveBuffer(self, buffer):
'''Check for any incoming packets and return if found'''
# Check to make sure the first byte is a start byte
# If not, clean up bad bytes
if buffer[0] != START_BYTE:
# Remove everything before
start = buffer.index(START_BYTE)
logger.debug('Bad/incomplete data found in buffer before start byte: %s' % ','.join(protocols.toHex(buffer[0:start])))
del buffer[0:start]
# If no end byte, try again later when the rest of the packet has arrived
if END_BYTE not in buffer:
# Quick check to make sure there isn't another packet banked up after
# an incomplete one
if not buffer.index(START_BYTE, 1):
return
start = buffer.index(START_BYTE, 1)
logger.debug('Bad/incomplete packet found in buffer before a legitimate packet: %s' % ','.join(protocols.toHex(buffer[0:start])))
del buffer[0:start]
return
# Begin state control machine :-)
state = STATE_NOT_PACKET
index = 0
packet = []
bad_bytes = []
complete = False
# Loop through buffer_copy, delete from buffer
buffer_copy = copy.copy(buffer)
for byte in buffer_copy:
# If have not started a packet yet check for start_byte
if state == STATE_NOT_PACKET:
# If not a start byte, we should never have got here
if byte != START_BYTE:
raise Exception, 'Should never have got here, expecting a start byte'
# Otherwise, start packet
else:
state = STATE_IN_PACKET
packet.append(START_BYTE)
# We are in a packet, save byte unless we find an end byte
elif state == STATE_IN_PACKET:
if byte == END_BYTE:
state = STATE_NOT_PACKET
packet.append(END_BYTE)
elif byte == ESCAPE_BYTE:
state = STATE_ESCAPE_BYTE
else:
packet.append(byte)
# If we are in escape mode (previous byte was an escape), escape byte
elif state == STATE_ESCAPE_BYTE:
esc_byte = byte ^ 0xFF
# Check it is a legitimately escaped byte
if esc_byte in (START_BYTE, ESCAPE_BYTE, END_BYTE):
packet.append(esc_byte)
else:
logger.error('Wrongly escaped byte found in buffer: %X' % byte)
# Remove this byte from buffer as it has been processed
del buffer[0]
index += 1
# Check if we have a complete packet
if len(packet) and state == STATE_NOT_PACKET:
complete = self.processIncomingPacket(packet)
break
# Process bad_bytes buffer
if len(bad_bytes):
logger.debug('Bad/incomplete data found in buffer before start byte: %s' % ','.join(protocols.toHex(bad_bytes)))
return complete
