generate packing for python messages (#1535)

Generate packet serialization in Python, too.

photon-lib/py/photonlibpy/packet.py

@@ -22,7 +22,7 @@ import wpilib
 
 
 class Packet:
-    def __init__(self, data: bytes):
+    def __init__(self, data: bytes = b""):
         """
         * Constructs an empty packet.
         *
@@ -198,3 +198,110 @@ class Packet:
             return serde.unpack(self)
         else:
             return None
+
+    def _encodeGeneric(self, packFormat, value):
+        """
+        Append bytes to the packet data buffer.
+        """
+        self.packetData = self.packetData + struct.pack(packFormat, value)
+        self.size = len(self.packetData)
+
+    def encode8(self, value: int):
+        """
+        Encodes a single byte and appends it to the packet.
+        """
+        self._encodeGeneric("<b", value)
+
+    def encode16(self, value: int):
+        """
+        Encodes a short (2 bytes) and appends it to the packet.
+        """
+        self._encodeGeneric("<h", value)
+
+    def encodeInt(self, value: int):
+        """
+        Encodes an int (4 bytes) and appends it to the packet.
+        """
+        self._encodeGeneric("<l", value)
+
+    def encodeFloat(self, value: float):
+        """
+        Encodes a float (4 bytes) and appends it to the packet.
+        """
+        self._encodeGeneric("<f", value)
+
+    def encodeLong(self, value: int):
+        """
+        Encodes a long (8 bytes) and appends it to the packet.
+        """
+        self._encodeGeneric("<q", value)
+
+    def encodeDouble(self, value: float):
+        """
+        Encodes a double (8 bytes) and appends it to the packet.
+        """
+        self._encodeGeneric("<d", value)
+
+    def encodeBoolean(self, value: bool):
+        """
+        Encodes a boolean as a single byte and appends it to the packet.
+        """
+        self.encode8(1 if value else 0)
+
+    def encodeDoubleArray(self, values: list[float]):
+        """
+        Encodes an array of doubles and appends it to the packet.
+        """
+        self.encode8(len(values))
+        for value in values:
+            self.encodeDouble(value)
+
+    def encodeShortList(self, values: list[int]):
+        """
+        Encodes a list of shorts, with length prefixed as a single byte.
+        """
+        self.encode8(len(values))
+        for value in values:
+            self.encode16(value)
+
+    def encodeTransform(self, transform: Transform3d):
+        """
+        Encodes a Transform3d (translation and rotation) and appends it to the packet.
+        """
+        # Encode Translation3d part (x, y, z)
+        self.encodeDouble(transform.translation().x)
+        self.encodeDouble(transform.translation().y)
+        self.encodeDouble(transform.translation().z)
+
+        # Encode Rotation3d as Quaternion (w, x, y, z)
+        quaternion = transform.rotation().getQuaternion()
+        self.encodeDouble(quaternion.W())
+        self.encodeDouble(quaternion.X())
+        self.encodeDouble(quaternion.Y())
+        self.encodeDouble(quaternion.Z())
+
+    def encodeList(self, values: list[Any], serde: Type):
+        """
+        Encodes a list of items using a specific serializer and appends it to the packet.
+        """
+        self.encode8(len(values))
+        for item in values:
+            packed = serde.pack(item)
+            self.packetData = self.packetData + packed.getData()
+            self.size = len(self.packetData)
+
+    def encodeOptional(self, value: Optional[Any], serde: Type):
+        """
+        Encodes an optional value using a specific serializer.
+        """
+        if value is None:
+            self.encodeBoolean(False)
+        else:
+            self.encodeBoolean(True)
+            packed = serde.pack(value)
+            self.packetData = self.packetData + packed.getData()
+            self.size = len(self.packetData)
+
+    def encodeBytes(self, value: bytes):
+        self.packetData = self.packetData + value
+        self.size = len(self.packetData)