###############################################################################
#
# The MIT License (MIT)
#
# Copyright (c) Crossbar.io Technologies GmbH
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
###############################################################################
try:
# use Cython implementation of XorMasker validator if available
from wsaccel.xormask import XorMaskerNull
# noinspection PyUnresolvedReferences
from wsaccel.xormask import createXorMasker
create_xor_masker = createXorMasker
except ImportError:
# fallback to pure Python implementation (this is faster on PyPy than above!)
# http://stackoverflow.com/questions/15014310/python3-xrange-lack-hurts
try:
# noinspection PyUnresolvedReferences
xrange
except NameError:
# Python 3
# noinspection PyShadowingBuiltins
xrange = range
from array import array
class XorMaskerNull(object):
__slots__ = ('_ptr',)
# noinspection PyUnusedLocal
def __init__(self, mask=None):
self._ptr = 0
def pointer(self):
return self._ptr
def reset(self):
self._ptr = 0
def process(self, data):
self._ptr += len(data)
return data
class XorMaskerSimple(object):
__slots__ = ('_ptr', '_msk')
def __init__(self, mask):
assert len(mask) == 4
self._ptr = 0
self._msk = array('B', mask)
def pointer(self):
return self._ptr
def reset(self):
self._ptr = 0
def process(self, data):
dlen = len(data)
payload = array('B', data)
for k in xrange(dlen):
payload[k] ^= self._msk[self._ptr & 3]
self._ptr += 1
return payload.tobytes()
class XorMaskerShifted1(object):
__slots__ = ('_ptr', '_mskarray')
def __init__(self, mask):
assert len(mask) == 4
self._ptr = 0
self._mskarray = [array('B'), array('B'), array('B'), array('B')]
for j in xrange(4):
self._mskarray[0].append(mask[j & 3])
self._mskarray[1].append(mask[(j + 1) & 3])
self._mskarray[2].append(mask[(j + 2) & 3])
self._mskarray[3].append(mask[(j + 3) & 3])
def pointer(self):
return self._ptr
def reset(self):
self._ptr = 0
def process(self, data):
dlen = len(data)
payload = array('B', data)
msk = self._mskarray[self._ptr & 3]
for k in xrange(dlen):
payload[k] ^= msk[k & 3]
self._ptr += dlen
return payload.tobytes()
[docs] def create_xor_masker(mask, length=None):
if length is None or length < 128:
return XorMaskerSimple(mask)
else:
return XorMaskerShifted1(mask)