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# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2011,2017 Nominum, Inc.
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose with or without fee is hereby granted,
# provided that the above copyright notice and this permission notice
# appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""DNS Wire Data Helper"""
import dns.exception
class WireData(bytes):
# WireData is a binary type with stricter slicing
def __getitem__(self, key):
try:
if isinstance(key, slice):
# make sure we are not going outside of valid ranges,
# do stricter control of boundaries than python does
# by default
for index in (key.start, key.stop):
if index is None:
continue
elif abs(index) > len(self):
raise dns.exception.FormError
return WireData(super().__getitem__(key))
return self.unwrap()[key]
except IndexError:
raise dns.exception.FormError
def unwrap(self):
return bytes(self)
def maybe_wrap(wire):
if isinstance(wire, WireData):
return wire
elif isinstance(wire, bytes):
return WireData(wire)
elif isinstance(wire, str):
return WireData(wire.encode())
raise ValueError("unhandled type %s" % type(wire))
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