mhchia 86d4ce1da8 Add delim_encode and delim_read
- Add `StreamCommunicator` and `RawConnectionCommunicator`, read/write
messages with delim codec, with `IMuxedStream` and `IRawConnection`
respectively.
- Use it in `Multiselect` and `MultiselectClient`.
2019-08-18 19:51:04 +08:00

48 lines
1.0 KiB
Python

import asyncio
import struct
from typing import Tuple
from libp2p.typing import StreamReader
def encode_uvarint(number: int) -> bytes:
"""Pack `number` into varint bytes"""
buf = b""
while True:
towrite = number & 0x7F
number >>= 7
if number:
buf += bytes((towrite | 0x80,))
else:
buf += bytes((towrite,))
break
return buf
def decode_uvarint(buff: bytes, index: int) -> Tuple[int, int]:
shift = 0
result = 0
while True:
i = buff[index]
result |= (i & 0x7F) << shift
shift += 7
if not i & 0x80:
break
index += 1
return result, index + 1
async def decode_uvarint_from_stream(reader: StreamReader, timeout: float) -> int:
shift = 0
result = 0
while True:
byte = await asyncio.wait_for(reader.read(1), timeout=timeout)
i = struct.unpack(">H", b"\x00" + byte)[0]
result |= (i & 0x7F) << shift
shift += 7
if not i & 0x80:
break
return result