Justin
105 lines
3.9 KiB
Python
105 lines
3.9 KiB
Python
"""BTD 700 control protocol. No updater transport or arbitrary commands."""
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from dataclasses import dataclass
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from enum import IntEnum
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import re
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REPORT_ID = 0x34
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REPORT_SIZE = 64
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class ProtocolError(Exception):
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pass
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class Command(IntEnum):
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GET_MODE = 0x01
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SET_MODE = 0x02
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GET_CODECS = 0x03
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SET_CODEC = 0x04
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GET_CODEC = 0x05
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GET_STATE = 0x06
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GET_LE_STATE = 0x07
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GET_QUALITY = 0x08
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GET_BROADCAST = 0x09
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SET_BROADCAST = 0x0A
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GET_KEY = 0x0B
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SET_KEY = 0x0C
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GET_NAME = 0x0D
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SET_NAME = 0x0E
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GET_VERSION = 0x12
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FACTORY_RESET = 0x13
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SET_CONNECTION = 0x14
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GET_TRANSPORTS = 0x15
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GET_GAMING = 0x17
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READ_COMMANDS = frozenset(c for c in Command if c.name.startswith('GET_'))
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EVENTS = frozenset((2, 3, 4, 15, 16, 17, 22, 23))
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CODECS = {1: 'SBC', 2: 'aptX Classic', 4: 'aptX Adaptive', 8: 'aptX Lossless',
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16: 'aptX Lite (QMAP)', 32: 'LC3'}
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MODES = {0: 'Standard', 1: 'Gaming', 2: 'Auracast'}
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TRANSPORTS = {0: 'Nicht verbunden', 1: 'Bluetooth Classic', 2: 'LE Audio', 3: 'Automatisch'}
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STATES = {0: 'Bereit', 1: 'Kopfhörer getrennt', 2: 'Kopfhörer verbunden',
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3: 'Musikwiedergabe', 4: 'Sprachanruf'}
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MIN_LENGTHS = {Command.GET_MODE: 2, Command.GET_CODECS: 1, Command.GET_CODEC: 1,
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Command.GET_STATE: 1, Command.GET_LE_STATE: 1, Command.GET_QUALITY: 2,
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Command.GET_BROADCAST: 3, Command.GET_VERSION: 3,
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Command.GET_TRANSPORTS: 1, Command.GET_GAMING: 1}
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def validate_text(value: str, *, key: bool = False) -> bytes:
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"""Match the original app's 4–16 ASCII character input bounds; empty resets."""
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pattern = r'[A-Za-z0-9]{4,16}' if key else r'[A-Za-z0-9 ]{4,16}'
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if value and (not re.fullmatch(pattern, value) or value != value.strip()):
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what = 'Passwort: 4–16 Buchstaben oder Ziffern.' if key else (
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'Name: 4–16 Buchstaben, Ziffern oder innere Leerzeichen.')
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raise ValueError(what)
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return value.encode('ascii')
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def encode(command: Command, payload: bytes = b'') -> bytes:
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try:
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command = Command(command)
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except ValueError as exc:
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raise ValueError('Unbekannter Steuerbefehl; kein Zugriff auf Update-Befehle.') from exc
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if command in READ_COMMANDS or command == Command.FACTORY_RESET:
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valid = not payload
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elif command == Command.SET_MODE:
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valid = len(payload) == 2 and payload[0] in MODES and payload[1] in (1, 2, 3)
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elif command == Command.SET_CODEC:
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valid = len(payload) == 1 and payload[0] in CODECS
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elif command == Command.SET_CONNECTION:
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valid = payload in (b'\0', b'\1')
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elif command == Command.SET_BROADCAST:
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valid = len(payload) == 3 and payload[0] in (0, 1) and payload[1] in (0, 1, 2) and payload[2] in (0, 1)
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elif command in (Command.SET_NAME, Command.SET_KEY):
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# Existing device names can contain an underscore. New user input is
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# validated more narrowly by validate_text, preserving originals on undo.
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valid = len(payload) <= 16 and all(32 <= b <= 126 for b in payload)
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else:
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valid = False
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if not valid:
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raise ValueError(f'Ungültige Parameter für {command.name}.')
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return bytes((REPORT_ID, 0xFE, command, len(payload))) + payload + bytes(60 - len(payload))
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def acknowledge(event: int) -> bytes:
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if event not in EVENTS:
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raise ProtocolError(f'Unbekannte Benachrichtigung: {event:#x}')
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return bytes((REPORT_ID, 0xFD, event, 0)) + bytes(60)
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@dataclass(frozen=True)
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class Message:
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kind: int
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command: int
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payload: bytes
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def decode(report: bytes) -> Message | None:
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if not report or report[0] != REPORT_ID:
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return None # Media keys share the same interface.
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if len(report) < 4 or report[1] not in (0xFC, 0xFF) or report[3] > 60 or len(report) < 4 + report[3]:
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raise ProtocolError('Ungültige Antwort des Dongles.')
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return Message(report[1], report[2], report[4:4 + report[3]])
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