| """ |
| Copyright (c) 2024, The OpenThread Authors. |
| All rights reserved. |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions are met: |
| 1. Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| 2. Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| 3. Neither the name of the copyright holder nor the |
| names of its contributors may be used to endorse or promote products |
| derived from this software without specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE |
| LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| POSSIBILITY OF SUCH DAMAGE. |
| """ |
| |
| from __future__ import annotations |
| from typing import List |
| |
| |
| class TLV(): |
| |
| def __init__(self, type: int = None, value: bytes = None): |
| self.type: int = type |
| self.value: bytes = value |
| |
| def __str__(self): |
| return f'TLV\n\tTYPE:\t0x{self.type:02x}\n\tVALUE:\t{self.value}' |
| |
| @staticmethod |
| def parse_tlvs(data: bytes) -> List[TLV]: |
| res: List[TLV] = [] |
| while data: |
| next_tlv = TLV.from_bytes(data) |
| next_tlv_size = len(next_tlv.to_bytes()) |
| data = data[next_tlv_size:] |
| res.append(next_tlv) |
| return res |
| |
| @staticmethod |
| def from_bytes(data: bytes) -> TLV: |
| res = TLV() |
| res.set_from_bytes(data) |
| return res |
| |
| def set_from_bytes(self, data: bytes): |
| self.type = data[0] |
| header_len = 2 |
| if data[1] == 0xFF: |
| header_len = 4 |
| length = int.from_bytes(data[1:header_len], byteorder='big') |
| self.value = data[header_len:header_len + length] |
| |
| def to_bytes(self) -> bytes: |
| has_long_header = len(self.value) >= 255 |
| header_len = 4 if has_long_header else 2 |
| len_bytes = len(self.value).to_bytes(header_len - 1, byteorder='big') |
| header = bytes([self.type]) + len_bytes |
| return header + self.value |