refactored

ubx/ubx.py

@@ -1,8 +1,6 @@
 import struct
 
-from msg_container import MsgContainer
-from msg_sink import MsgSink
-
+UBX_SYNC_WORD = b'\xb5\x62'
 
 def checksum(data: bytes) -> bytes:
 	ck_a = 0
@@ -22,59 +20,49 @@ def frame_create(_class: int, _id: int, _data: bytes) -> bytes:
 
 	return _sync + _hdr + _data + _check
 
+class Hdr:
+	def __init__(self, _class: int, _id: int, _length: int):
+		self.mclass = _class
+		self.mid = _id
+		self.length = _length
+
+
+def frame_parse_hdr(frame: bytes) -> Hdr|None:
+	hdr = Hdr(0,0,0)
+
+	if len(frame) < 4:
+		return None
+
+	hdr.mclass = struct.unpack('B', frame[0:1])[0]
+	hdr.mid = struct.unpack('B', frame[1:2])[0]
+	hdr.length = struct.unpack('<H', frame[2:4])[0]
+
+	return hdr
+
 def frame_parse(frame: bytes):
-	_class = 0
-	_id = 0
 	_data = None
+	_hdr = Hdr(0,0,0)
 
 	while True:
-		hdr = frame[0:2]
-		if hdr != b'\xb5\x62':
+		_hdr = frame_parse_hdr(frame[0:4])
+		if _hdr is None:
 			break
 
-		_class = struct.unpack('B', frame[2:3])[0]
-		_id = struct.unpack('B', frame[3:4])[0]
-		_length = struct.unpack('<H', frame[4:6])[0]
-		if (6+_length+2) != len(frame):
+		if (4+_hdr.length+2) != len(frame):
 			break
 
 		_check_soll = frame[-2:]
-		_check_ist = checksum(frame[2:-2])
+		_check_ist = checksum(frame[0:-2])
 		if _check_soll != _check_ist:
 			break
 
-		_data = frame[6:-2]
+		_data = frame[4:-2]
 		break
 
-	return _data, _class, _id
-
-class UbxReceiver(MsgSink):
-	def __init__(self, name: str, mid: int, mclass: int):
-		MsgSink.__init__(self)
-		self.name = name
-		self.mid = mid
-		self.mclass = mclass
-
-	def on_recv(self, msg: MsgContainer):
-		data, mclass, mid = frame_parse(msg.data)
-		print(f"{mclass}:{mid}:{data}")
-
-
-	def is_msg(self, msg: MsgContainer):
-		data, mclass, mid = frame_parse(msg.data)
-		if data is None:
-			return False
-
-		if mclass != self.mclass:
-			return False
-
-		if mid != self.mid:
-			return False
-
-		return True
+	return _data, _hdr
 
 if __name__ == "__main__":
 	result = frame_create(1, 2, b'Hallo')
 	print(result)
-	payload, msg_class, msg_id = frame_parse(result)
+	payload, hdr = frame_parse(result)
 	print(payload)