mirror of
https://github.com/KevinMidboe/python-gpiozero.git
synced 2025-10-29 17:50:37 +00:00
141 lines
3.8 KiB
Python
141 lines
3.8 KiB
Python
# vim: set fileencoding=utf-8:
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from __future__ import (
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unicode_literals,
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absolute_import,
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print_function,
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division,
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)
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str = type('')
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import cmath
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import weakref
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import collections
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import operator
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import functools
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# Back-ported from python 3.5; see
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# github.com/PythonCHB/close_pep/blob/master/is_close.py for original
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# implementation
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def isclose(a, b, rel_tol=1e-9, abs_tol=0.0):
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if rel_tol < 0.0 or abs_tol < 0.0:
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raise ValueError('error tolerances must be non-negative')
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if a == b: # fast-path for exact equality
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return True
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if cmath.isinf(a) or cmath.isinf(b):
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return False
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diff = abs(b - a)
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return (
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(diff <= abs(rel_tol * b)) or
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(diff <= abs(rel_tol * a)) or
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(diff <= abs_tol)
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)
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# Backported from py3.4
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def mean(data):
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if iter(data) is data:
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data = list(data)
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n = len(data)
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if not n:
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raise ValueError('cannot calculate mean of empty data')
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return sum(data) / n
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# Backported from py3.4
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def median(data):
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data = sorted(data)
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n = len(data)
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if not n:
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raise ValueError('cannot calculate median of empty data')
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elif n % 2:
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return data[n // 2]
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else:
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i = n // 2
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return (data[i - 1] + data[i]) / 2
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# Copied from the MIT-licensed https://github.com/slezica/python-frozendict
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class frozendict(collections.Mapping):
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def __init__(self, *args, **kwargs):
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self.__dict = dict(*args, **kwargs)
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self.__hash = None
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def __getitem__(self, key):
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return self.__dict[key]
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def copy(self, **add_or_replace):
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return frozendict(self, **add_or_replace)
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def __iter__(self):
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return iter(self.__dict)
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def __len__(self):
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return len(self.__dict)
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def __repr__(self):
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return '<frozendict %s>' % repr(self.__dict)
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def __hash__(self):
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if self.__hash is None:
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hashes = map(hash, self.items())
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self.__hash = functools.reduce(operator.xor, hashes, 0)
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return self.__hash
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# Backported from py3.4
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class WeakMethod(weakref.ref):
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"""
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A custom `weakref.ref` subclass which simulates a weak reference to
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a bound method, working around the lifetime problem of bound methods.
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"""
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__slots__ = "_func_ref", "_meth_type", "_alive", "__weakref__"
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def __new__(cls, meth, callback=None):
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try:
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obj = meth.__self__
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func = meth.__func__
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except AttributeError:
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raise TypeError("argument should be a bound method, not {0}"
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.format(type(meth)))
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def _cb(arg):
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# The self-weakref trick is needed to avoid creating a reference
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# cycle.
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self = self_wr()
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if self._alive:
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self._alive = False
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if callback is not None:
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callback(self)
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self = weakref.ref.__new__(cls, obj, _cb)
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self._func_ref = weakref.ref(func, _cb)
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self._meth_type = type(meth)
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self._alive = True
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self_wr = weakref.ref(self)
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return self
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def __call__(self):
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obj = super(WeakMethod, self).__call__()
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func = self._func_ref()
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if obj is None or func is None:
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return None
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return self._meth_type(func, obj)
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def __eq__(self, other):
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if isinstance(other, WeakMethod):
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if not self._alive or not other._alive:
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return self is other
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return weakref.ref.__eq__(self, other) and self._func_ref == other._func_ref
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return False
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def __ne__(self, other):
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if isinstance(other, WeakMethod):
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if not self._alive or not other._alive:
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return self is not other
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return weakref.ref.__ne__(self, other) or self._func_ref != other._func_ref
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return True
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__hash__ = weakref.ref.__hash__
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