61 lines
2.0 KiB
Python
61 lines
2.0 KiB
Python
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# The MIT License (MIT)
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#
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# Copyright (c) 2014 Richard Moore
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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# Why to_bufferable?
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# Python 3 is very different from Python 2.x when it comes to strings of text
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# and strings of bytes; in Python 3, strings of bytes do not exist, instead to
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# represent arbitrary binary data, we must use the "bytes" object. This method
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# ensures the object behaves as we need it to.
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def to_bufferable(binary):
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return binary
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def _get_byte(c):
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return ord(c)
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try:
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xrange
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except:
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def to_bufferable(binary):
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if isinstance(binary, bytes):
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return binary
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return bytes(ord(b) for b in binary)
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def _get_byte(c):
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return c
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def append_PKCS7_padding(data):
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pad = 16 - (len(data) % 16)
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return data + to_bufferable(chr(pad) * pad)
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def strip_PKCS7_padding(data):
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if len(data) % 16 != 0:
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raise ValueError("invalid length")
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pad = _get_byte(data[-1])
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if pad > 16:
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raise ValueError("invalid padding byte")
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return data[:-pad]
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