Source code for spinnman.messages.sdp.sdp_message
# Copyright (c) 2014 The University of Manchester
#
# 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 typing import Optional
from .sdp_header import SDPHeader
class SDPMessage(object):
"""
Wraps up an SDP message with a header and optional data.
"""
__slots__ = (
"_data",
"_offset",
"_sdp_header")
def __init__(self, sdp_header: SDPHeader,
data: Optional[bytes] = None, offset: int = 0):
"""
:param SDPHeader sdp_header: The header of the message
:param data: The data of the SDP packet, or `None` if no data
:type data: bytes or bytearray or None
:param int offset: The offset where the valid data starts
"""
self._sdp_header = sdp_header
self._data = data
self._offset = offset
@property
def bytestring(self) -> bytes:
"""
The byte-string of the message.
:rtype: bytes
"""
if self._data is not None:
return self._sdp_header.bytestring + self._data[self._offset:]
return self._sdp_header.bytestring
[docs]
@staticmethod
def from_bytestring(data: bytes, offset: int) -> 'SDPMessage':
"""
:param bytes data:
:param int offset:
:rtype: SDPMessage
"""
sdp_header = SDPHeader.from_bytestring(data, offset)
return SDPMessage(sdp_header, data, offset + 8)
@property
def sdp_header(self) -> SDPHeader:
"""
The header of the packet.
:rtype: SDPHeader
"""
return self._sdp_header
@property
def data(self) -> Optional[bytes]:
"""
The data in the packet.
:rtype: bytes or bytearray or None
"""
return self._data
@property
def offset(self) -> int:
"""
The offset where the valid data starts.
:rtype: int
"""
return self._offset