71 lines
1.9 KiB
Python
71 lines
1.9 KiB
Python
# Copyright (C) 2014 Andrey Golovizin
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import functools
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import itertools
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from collections import defaultdict
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from threading import Lock
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def cached_property(fun):
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"""A memoize decorator for class properties."""
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lock = Lock()
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@functools.wraps(fun)
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def get(self):
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with lock:
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try:
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obj_locks = self._locks
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except AttributeError:
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obj_locks = self._locks = defaultdict(Lock)
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obj_lock = obj_locks[fun]
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with obj_lock:
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try:
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cache = self._cache
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except AttributeError:
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cache = self._cache = {}
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try:
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ret = cache[fun]
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except KeyError:
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ret = cache[fun] = fun(self)
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return ret
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return property(get)
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def collect_iterable(func):
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@functools.wraps(func)
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def collect(*args, **kwargs):
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return list(func(*args, **kwargs))
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return collect
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def pairwise(iterable):
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a, b = itertools.tee(iterable)
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next(b, None)
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return itertools.zip_longest(a, b)
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def neighbourhood(lst, index, window=5):
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"""Return adjacent list items."""
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before = lst[:index]
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after = lst[index + 1:]
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return before[-window:] + after[:window]
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def pipe(value, *funcs):
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for func in funcs:
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value = func(value)
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return value
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