Serialization & Deserialization

import struct

# SOME/IP serialisation: big-endian (network byte order) by default per PRS_SOMEIP_00077
# Data types: uint8/16/32/64, sint8/16/32/64, float32/64, string (4B length + UTF-8), array (4B length + elements)

class SomeIpSerializer:
    def __init__(self):
        self.buf = bytearray()

    def write_uint8(self, v):   self.buf += struct.pack(">B", v)
    def write_uint16(self, v):  self.buf += struct.pack(">H", v)
    def write_uint32(self, v):  self.buf += struct.pack(">I", v)
    def write_float32(self, v): self.buf += struct.pack(">f", v)

    def write_string(self, s: str):
        encoded = s.encode("utf-8")
        self.buf += struct.pack(">I", len(encoded))  # 4-byte length prefix
        self.buf += encoded

    def write_array_uint16(self, arr):
        self.buf += struct.pack(">I", len(arr) * 2)  # 4-byte length prefix in bytes
        for v in arr: self.write_uint16(v)

    def bytes(self): return bytes(self.buf)

# Example: serialise a VehicleData struct
ser = SomeIpSerializer()
ser.write_float32(100.0)   # speed_kmh
ser.write_uint8(3)          # gear
ser.write_string("ECU_01")  # ecu_name
print(f"Serialised: {ser.bytes().hex()}")
# → 42c80000 (100.0f) 03 (gear) 00000006 (len=6) 454355_3031 (ECU_01)

  SomeIpProps_VehicleSpeed
  MOST-SIGNIFICANT-BYTE-FIRST  
  1
  NOTIFICATION
  4