| # Copyright 2023 Google LLC |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # https://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| |
| from dataclasses import dataclass |
| from typing import Tuple |
| |
| |
| @dataclass |
| class SizedCustomField: |
| |
| def __init__(self, value: int = 0): |
| self.value = value |
| |
| def parse(span: bytes) -> Tuple['SizedCustomField', bytes]: |
| return (SizedCustomField(span[0]), span[1:]) |
| |
| def parse_all(span: bytes) -> 'SizedCustomField': |
| assert (len(span) == 1) |
| return SizedCustomField(span[0]) |
| |
| @property |
| def size(self) -> int: |
| return 1 |
| |
| |
| @dataclass |
| class UnsizedCustomField: |
| |
| def __init__(self, value: int = 0): |
| self.value = value |
| |
| def parse(span: bytes) -> Tuple['UnsizedCustomField', bytes]: |
| return (UnsizedCustomField(span[0]), span[1:]) |
| |
| def parse_all(span: bytes) -> 'UnsizedCustomField': |
| assert (len(span) == 1) |
| return UnsizedCustomField(span[0]) |
| |
| @property |
| def size(self) -> int: |
| return 1 |
| |
| |
| def Checksum(span: bytes) -> int: |
| return sum(span) % 256 |