101 lines
3.5 KiB
Python
101 lines
3.5 KiB
Python
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# Copyright 2009-2017 Wander Lairson Costa
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# Copyright 2009-2021 PyUSB contributors
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met:
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#
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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#
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the distribution.
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#
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# 3. Neither the name of the copyright holder nor the names of its
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# contributors may be used to endorse or promote products derived from
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# this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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# All the hacks necessary to assure compatibility across all
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# supported versions come here.
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# Please, note that there is one version check for each
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# hack we need to do, this makes maintenance easier... ^^
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import sys
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import array
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__all__ = ['_reduce', '_set', '_next', '_update_wrapper']
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# we support Python >= 2.4
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assert sys.hexversion >= 0x020400f0
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# On Python 3, reduce became a functools module function
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try:
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import functools
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_reduce = functools.reduce
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except (ImportError, AttributeError):
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_reduce = reduce
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# all, introduced in Python 2.5
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try:
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_all = all
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except NameError:
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_all = lambda iter_ : _reduce( lambda x, y: x and y, iter_, True )
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# we only have the builtin set type since 2.5 version
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try:
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_set = set
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except NameError:
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import sets
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_set = sets.Set
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# On Python >= 2.6, we have the builtin next() function
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# On Python 2.5 and before, we have to call the iterator method next()
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def _next(iter):
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try:
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return next(iter)
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except NameError:
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return iter.next()
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# functools appeared in 2.5
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try:
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import functools
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_update_wrapper = functools.update_wrapper
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except (ImportError, AttributeError):
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def _update_wrapper(wrapper, wrapped):
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wrapper.__name__ = wrapped.__name__
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wrapper.__module__ = wrapped.__module__
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wrapper.__doc__ = wrapped.__doc__
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wrapper.__dict__ = wrapped.__dict__
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# this is used (as of May 2015) twice in core, once in backend/openusb, and in
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# some unit test code. It would probably be clearer if written in terms of some
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# definite 3.2+ API (bytearrays?) with a fallback provided for 2.4+.
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def as_array(data=None):
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if data is None:
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return array.array('B')
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if isinstance(data, array.array):
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return data
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try:
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return array.array('B', data)
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except TypeError:
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# When you pass a unicode string or a character sequence,
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# you get a TypeError if the first parameter does not match
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a = array.array('B')
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a.frombytes(data.encode('utf-8'))
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return a
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