diff options
Diffstat (limited to '.venv/lib/python3.12/site-packages/dns/wire.py')
-rw-r--r-- | .venv/lib/python3.12/site-packages/dns/wire.py | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/dns/wire.py b/.venv/lib/python3.12/site-packages/dns/wire.py new file mode 100644 index 00000000..9f9b1573 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/dns/wire.py @@ -0,0 +1,89 @@ +# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license + +import contextlib +import struct +from typing import Iterator, Optional, Tuple + +import dns.exception +import dns.name + + +class Parser: + def __init__(self, wire: bytes, current: int = 0): + self.wire = wire + self.current = 0 + self.end = len(self.wire) + if current: + self.seek(current) + self.furthest = current + + def remaining(self) -> int: + return self.end - self.current + + def get_bytes(self, size: int) -> bytes: + assert size >= 0 + if size > self.remaining(): + raise dns.exception.FormError + output = self.wire[self.current : self.current + size] + self.current += size + self.furthest = max(self.furthest, self.current) + return output + + def get_counted_bytes(self, length_size: int = 1) -> bytes: + length = int.from_bytes(self.get_bytes(length_size), "big") + return self.get_bytes(length) + + def get_remaining(self) -> bytes: + return self.get_bytes(self.remaining()) + + def get_uint8(self) -> int: + return struct.unpack("!B", self.get_bytes(1))[0] + + def get_uint16(self) -> int: + return struct.unpack("!H", self.get_bytes(2))[0] + + def get_uint32(self) -> int: + return struct.unpack("!I", self.get_bytes(4))[0] + + def get_uint48(self) -> int: + return int.from_bytes(self.get_bytes(6), "big") + + def get_struct(self, format: str) -> Tuple: + return struct.unpack(format, self.get_bytes(struct.calcsize(format))) + + def get_name(self, origin: Optional["dns.name.Name"] = None) -> "dns.name.Name": + name = dns.name.from_wire_parser(self) + if origin: + name = name.relativize(origin) + return name + + def seek(self, where: int) -> None: + # Note that seeking to the end is OK! (If you try to read + # after such a seek, you'll get an exception as expected.) + if where < 0 or where > self.end: + raise dns.exception.FormError + self.current = where + + @contextlib.contextmanager + def restrict_to(self, size: int) -> Iterator: + assert size >= 0 + if size > self.remaining(): + raise dns.exception.FormError + saved_end = self.end + try: + self.end = self.current + size + yield + # We make this check here and not in the finally as we + # don't want to raise if we're already raising for some + # other reason. + if self.current != self.end: + raise dns.exception.FormError + finally: + self.end = saved_end + + @contextlib.contextmanager + def restore_furthest(self) -> Iterator: + try: + yield None + finally: + self.current = self.furthest |