def read_length_delimited(stream: io.BufferedIOBase) -> Optional[bytes]:
length = read_varint(stream)
if length is None:
return None
data = stream.read1(length)
return data if len(data) == length else None
def read_fixed(stream: io.BufferedIOBase,
wire_type: WireType) -> Optional[bytes]:
fixed_width = {WireType.Fixed32: 4, WireType.Fixed64: 8}
data = stream.read1(fixed_width[WireType(wire_type)])
if len(data) == 0 or len(data) != fixed_width[wire_type]:
return None
return data
def hash_file(fobj: io.BufferedIOBase,
blake2b_salt: str = None,
hash_size_bytes: int = DEFAULT_FILE_HASH_SIZE) -> (str, str):
if blake2b_salt is None:
salt = os.urandom(blake2b.SALT_SIZE)
blake2b_salt = salt.hex()
else:
salt = bytes.fromhex(blake2b_salt)
h = blake2b(digest_size=hash_size_bytes, salt=salt)
MAX_BUFFER = 1024 * 1024
while True:
buf = fobj.read1(MAX_BUFFER)
if not buf:
break
h.update(buf)
return h.hexdigest(), blake2b_salt
def _iter_bytes(stream: io.BufferedIOBase) -> Iterable[bytes]:
byte = stream.read1(1)
while len(byte) != 0:
yield byte
byte = stream.read1(1)
