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- # The MIT License (MIT)
- #
- # Copyright (c) 2014 Richard Moore
- #
- # 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.
-
- # Why to_bufferable?
- # Python 3 is very different from Python 2.x when it comes to strings of text
- # and strings of bytes; in Python 3, strings of bytes do not exist, instead to
- # represent arbitrary binary data, we must use the "bytes" object. This method
- # ensures the object behaves as we need it to.
-
- def to_bufferable(binary):
- return binary
-
- def _get_byte(c):
- return ord(c)
-
- try:
- xrange
- except:
-
- def to_bufferable(binary):
- if isinstance(binary, bytes):
- return binary
- return bytes(ord(b) for b in binary)
-
- def _get_byte(c):
- return c
-
- def append_PKCS7_padding(data):
- pad = 16 - (len(data) % 16)
- return data + to_bufferable(chr(pad) * pad)
-
- def strip_PKCS7_padding(data):
- if len(data) % 16 != 0:
- raise ValueError("invalid length")
-
- pad = _get_byte(data[-1])
-
- if pad > 16:
- raise ValueError("invalid padding byte")
-
- return data[:-pad]
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