some simplification and added type hints

PayloadBuilder.py

@@ -5,53 +5,53 @@ class PayloadBuilder:
     Utility for building binary payloads
     """
 
-    def __init__(self, endian='little'):
+    def __init__(self, endian:str='little'):
         self.buf = bytearray()
         self.endian = endian
 
-    def close(self):
+    def close(self) -> bytearray:
         """ Get the byte buffer """
         return self.buf
 
-    def u8(self, num):
+    def u8(self, num:int):
         """ Add a uint8_t """
         self.buf.extend(num.to_bytes(length=1, byteorder=self.endian, signed=False))
 
-    def u16(self, num):
+    def u16(self, num:int):
         """ Add a uint16_t """
         self.buf.extend(num.to_bytes(length=2, byteorder=self.endian, signed=False))
 
-    def u32(self, num):
+    def u32(self, num:int):
         """ Add a uint32_t """
         self.buf.extend(num.to_bytes(length=4, byteorder=self.endian, signed=False))
 
-    def i8(self, num):
+    def i8(self, num:int):
         """ Add a int8_t """
         self.buf.extend(num.to_bytes(length=1, byteorder=self.endian, signed=True))
 
-    def i16(self, num):
+    def i16(self, num:int):
         """ Add a int16_t """
         self.buf.extend(num.to_bytes(length=2, byteorder=self.endian, signed=True))
 
-    def i32(self, num):
+    def i32(self, num:int):
         """ Add a int32_t """
         self.buf.extend(num.to_bytes(length=4, byteorder=self.endian, signed=True))
 
-    def float(self, num):
+    def float(self, num:float):
         """ Add a float (4 bytes) """
         fmt = '<f' if self.endian == 'little' else '>f'
         self.buf.extend(struct.pack(fmt, num))
 
-    def double(self, num):
+    def double(self, num:float):
         """ Add a double (8 bytes) """
         fmt = '<d' if self.endian == 'little' else '>d'
         self.buf.extend(struct.pack(fmt, num))
 
-    def bool(self, num):
+    def bool(self, num:bool):
         """ Add a bool (0 or 1) """
         self.buf.append(1 if num != False else 0)
 
-    def str(self, string):
+    def str(self, string:str):
         """ Add a 0-terminated string """
         self.buf.extend(string.encode('utf-8'))
         self.buf.append(0)

PayloadParser.py

@@ -5,13 +5,13 @@ class PayloadParser:
     Utility for parsing a binary payload
     """
 
-    def __init__(self, buf, endian='little'):
+    def __init__(self, buf, endian:str='little'):
         """ buf - buffer to parse (bytearray or binary string) """
         self.buf = buf
         self.ptr = 0
         self.endian = endian
 
-    def _slice(self, n):
+    def _slice(self, n:int) -> bytearray:
         """ Extract a slice and advance the read pointer for the next slice """
         if self.ptr + n > len(self.buf):
             raise Exception("Out of bounds")
@@ -24,57 +24,57 @@ class PayloadParser:
         """ Reset the slice pointer to the beginning """
         self.ptr = 0
 
-    def tail(self):
+    def tail(self) -> bytearray:
         """ Get all remaining bytes """
         return self._slice(len(self.buf) - self.ptr)
 
-    def u8(self):
+    def u8(self) -> int:
         """ Read a uint8_t """
         slice = self._slice(1)
         return int.from_bytes(slice, byteorder=self.endian, signed=False)
 
-    def u16(self):
+    def u16(self) -> int:
         """ Read a uint16_t """
         slice = self._slice(2)
         return int.from_bytes(slice, byteorder=self.endian, signed=False)
 
-    def u32(self):
+    def u32(self) -> int:
         """ Read a uint32_t """
         slice = self._slice(4)
         return int.from_bytes(slice, byteorder=self.endian, signed=False)
 
-    def i8(self):
+    def i8(self) -> int:
         """ Read a int8_t """
         slice = self._slice(1)
         return int.from_bytes(slice, byteorder=self.endian, signed=True)
 
-    def i16(self):
+    def i16(self) -> int:
         """ Read a int16_t """
         slice = self._slice(2)
         return int.from_bytes(slice, byteorder=self.endian, signed=True)
 
-    def i32(self):
+    def i32(self) -> int:
         """ Read a int32_t """
         slice = self._slice(4)
         return int.from_bytes(slice, byteorder=self.endian, signed=True)
 
-    def float(self):
+    def float(self) -> float:
         """ Read a float (4 bytes) """
         slice = self._slice(4)
         fmt = '<f' if self.endian == 'little' else '>f'
         return struct.unpack(fmt, slice)[0]
 
-    def double(self):
+    def double(self) -> float:
         """ Read a double (8 bytes) """
         slice = self._slice(8)
         fmt = '<d' if self.endian == 'little' else '>d'
         return struct.unpack(fmt, slice)[0]
 
-    def bool(self):
+    def bool(self) -> bool:
         """ Read a bool (1 byte, True if != 0) """
         return 0 != self._slice(1)[0]
 
-    def str(self):
+    def str(self) -> str:
         """ Read a zero-terminated string """
         p = self.ptr
         while p < len(self.buf) and self.buf[p] != 0:
@@ -84,6 +84,6 @@ class PayloadParser:
         self.ptr += 1
         return bs.decode('utf-8')
 
-    def blob(self, length):
+    def blob(self, length) -> bytearray:
         """ Read a blob of given length """
         return self._slice(length)

TinyFrame.py

@@ -1,5 +1,5 @@
 class TinyFrame:
-    def __init__(self, peer=1):
+    def __init__(self, peer:int=1):
         self.write = None # the writer function should be attached here
 
         self.id_listeners = {}
@@ -38,6 +38,8 @@ class TinyFrame:
 
         self.reset_parser()
 
+        self._CKSUM_BYTES = None # will be updated on first compose / accept
+
     def reset_parser(self):
         # parser state: SOF, ID, LEN, TYPE, HCK, PLD, PCK
         self.ps = 'SOF'
@@ -50,8 +52,7 @@ class TinyFrame:
         # received frame
         self.rf = TF_Msg()
 
-    @property
-    def _CKSUM_BYTES(self):
+    def _calc_cksum_bytes(self):
         if self.CKSUM_TYPE == 'none' or self.CKSUM_TYPE is None:
             return 0
         elif self.CKSUM_TYPE == 'xor':
@@ -63,7 +64,7 @@ class TinyFrame:
         else:
             raise Exception("Bad cksum type!")
 
-    def _cksum(self, buffer):
+    def _cksum(self, buffer) -> int:
         if self.CKSUM_TYPE == 'none' or self.CKSUM_TYPE is None:
             return 0
 
@@ -84,11 +85,7 @@ class TinyFrame:
         else:
             raise Exception("Bad cksum type!")
 
-    @property
-    def _SOF_BYTES(self):
-        return 1 if self.USE_SOF_BYTE else 0
-
-    def _gen_frame_id(self):
+    def _gen_frame_id(self) -> int:
         """
         Get a new frame ID
         """
@@ -104,15 +101,15 @@ class TinyFrame:
 
         return frame_id
 
-    def _pack(self, num, bytes):
+    def _pack(self, num:int, bytes:int) -> bytes:
         """ Pack a number for a TF field """
         return num.to_bytes(bytes, byteorder='big', signed=False)
 
-    def _unpack(self, buf):
+    def _unpack(self, buf) -> int:
         """ Unpack a number from a TF field """
         return int.from_bytes(buf, byteorder='big', signed=False)
 
-    def query(self, type, listener, pld=None, id=None):
+    def query(self, type:int, listener, pld=None, id:int=None):
         """ Send a query """
         (id, buf) = self._compose(type=type, pld=pld, id=id)
 
@@ -121,19 +118,21 @@ class TinyFrame:
 
         self.write(buf)
 
-    def send(self, type, pld=None, id=None):
+    def send(self, type:int, pld=None, id:int=None):
         """ Like query, but with no listener """
         self.query(type=type, pld=pld, id=id, listener=None)
 
-    def _compose(self, type, pld=None, id=None):
+    def _compose(self, type:int, pld=None, id:int=None) -> tuple:
         """
         Compose a frame.
 
         frame_id can be an ID of an existing session, None for a new session.
         """
+        if self._CKSUM_BYTES is None:
+            self._CKSUM_BYTES = self._calc_cksum_bytes()
 
         if pld is None:
-            pld = b''
+            pld = bytearray()
 
         if id is None:
             id = self._gen_frame_id()
@@ -162,9 +161,12 @@ class TinyFrame:
         for b in bytes:
             self.accept_byte(b)
 
-    def accept_byte(self, b):
+    def accept_byte(self, b:int):
         # TODO this seems ripe for rewrite to avoid repetitive code
 
+        if self._CKSUM_BYTES is None:
+            self._CKSUM_BYTES = self._calc_cksum_bytes()
+
         if self.ps == 'SOF':
             if self.USE_SOF_BYTE:
                 if b != self.SOF_BYTE:
@@ -302,9 +304,9 @@ class TinyFrame:
             if rv == TF.CLOSE:
                 self.fallback_listener = None
 
-    def add_id_listener(self, id, lst, lifetime=None):
+    def add_id_listener(self, id:int, lst, lifetime:float=None):
         """
-        Add a ID listener that expires in "lifetime" ticks
+        Add a ID listener that expires in "lifetime" seconds
 
         listener function takes two arguments:
         tinyframe instance and a msg object
@@ -315,7 +317,7 @@ class TinyFrame:
             'age': 0,
         }
 
-    def add_type_listener(self, type, lst):
+    def add_type_listener(self, type:int, lst):
         """
         Add a type listener