mirror of
https://github.com/varun-r-mallya/py-libp2p.git
synced 2025-12-31 20:36:24 +00:00
79 lines
1.8 KiB
Python
79 lines
1.8 KiB
Python
import asyncio
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import struct
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from typing import Tuple
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from libp2p.typing import StreamReader
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TIMEOUT = 10
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def encode_uvarint(number: int) -> bytes:
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"""Pack `number` into varint bytes"""
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buf = b""
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while True:
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towrite = number & 0x7F
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number >>= 7
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if number:
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buf += bytes((towrite | 0x80,))
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else:
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buf += bytes((towrite,))
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break
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return buf
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def decode_uvarint(buff: bytes, index: int) -> Tuple[int, int]:
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shift = 0
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result = 0
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while True:
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i = buff[index]
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result |= (i & 0x7F) << shift
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shift += 7
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if not i & 0x80:
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break
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index += 1
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return result, index + 1
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async def decode_uvarint_from_stream(reader: StreamReader, timeout: float) -> int:
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shift = 0
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result = 0
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while True:
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byte = await asyncio.wait_for(reader.read(1), timeout=timeout)
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i = struct.unpack(">H", b"\x00" + byte)[0]
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result |= (i & 0x7F) << shift
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shift += 7
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if not i & 0x80:
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break
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return result
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# Varint-prefixed read/write
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def encode_varint_prefixed(msg_bytes: bytes) -> bytes:
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varint_len = encode_uvarint(len(msg_bytes))
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return varint_len + msg_bytes
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async def read_varint_prefixed_bytes(
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reader: StreamReader, timeout: int = TIMEOUT
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) -> bytes:
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len_msg = await decode_uvarint_from_stream(reader, timeout)
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return await reader.read(len_msg)
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# Delimited read/write
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def encode_delim(msg_str: str) -> bytes:
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delimited_msg = msg_str + "\n"
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return encode_varint_prefixed(delimited_msg.encode())
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async def read_delim(reader: StreamReader, timeout: int = TIMEOUT) -> str:
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msg_bytes = await read_varint_prefixed_bytes(reader, timeout)
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return msg_bytes.decode().rstrip()
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