read/write WPE spt files

spt.py

import bson
import struct

from enum import Enum

class SPT:
    def __init__(self):
        pass

    class Packet:
        def __init__(self, name, data):
            self.name = name
            self.data = data

    class State(Enum):
        HEAD = 1
        NAME = 2
        DATA = 3

    def read_int(self, bytes, index):
        return index + 4, struct.unpack('i', bytes[index:index+4])[0]

    def read_str(self, bytes, index, count):
        return index + count, struct.unpack(str(count) + 's', bytes[index:index+count])[0]

    def read_bytes(self, bytes, index, count):
        return index + count, bytearray(struct.unpack(str(count) + 's', bytes[index:index+count])[0])

    def deserialize(self, input_bytes):
        input_bytes = bytearray(input_bytes)
        packets = []
        
        index, capacity, = self.read_int(input_bytes, 0)

        for i in range(0, capacity):
            index, name_length, = self.read_int(input_bytes, index)
            index, name, = self.read_str(input_bytes, index, name_length)
            index, data_length, = self.read_int(input_bytes, index)
            index, data, = self.read_bytes(input_bytes, index, data_length);

            packets.append(Packet(name, data))
        pass
        
        return packets

    def serialize(self, packet):
        bytes = bytearray()

        bytes += struct.pack('i', len(packets))

        bytes += struct.pack('i', len(packet.name))
        bytes += struct.pack(str(len(packet.name)) + 's', packet.name)

        bytes += struct.pack('i', len(packet.data))
        bytes += struct.pack(str(len(packet.data)) + 's', packet.data)

        return bytes