production init

front/oscar/proto/tlv.py

@@ -0,0 +1,54 @@
+from . import buffer   # because of circular imports, would've prefered to do `from .buffer import ...` but oh well
+
+from dataclasses import dataclass
+from typing import Optional
+
+
+@dataclass
+class TLV:
+	__slots__ = ('type', 'data')
+
+	type: int
+	data: bytes
+
+	def __init__(self, type: int, data: bytes | str = b''):
+		self.type = type
+
+		if isinstance(data, str):
+			self.data = data.encode()
+		else:
+			self.data = data
+
+	def marshal(self) -> bytes:
+		buf = buffer.Buffer()
+		buf.write_u16(self.type)
+		buf.write_u16(len(self.data))
+		buf.write_bytes(self.data)
+
+		return buf.data
+
+
+def marshal_tlvs(tlvs: list[TLV]) -> bytes:
+	return b''.join([tlv.marshal() for tlv in tlvs])
+
+
+def unmarshal_tlvs(data: bytes) -> list[TLV]:
+	buf = buffer.Buffer(data)
+	tlvs = []
+
+	while len(buf) > 4:
+		type = buf.read_u16()
+		length = buf.read_u16()
+		value = buf.read_bytes(length)
+
+		tlvs.append(TLV(type, value))
+
+	return tlvs
+
+
+def find_tlv(tlvs: list[TLV], type: int) -> Optional[TLV]:
+	for tlv in tlvs:
+		if tlv.type == type:
+			return tlv
+
+	return None