41 lines
1.0 KiB
Python
41 lines
1.0 KiB
Python
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# -*- coding: utf-8 -*-
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"""
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hyperframe/flags
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~~~~~~~~~~~~~~~~
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Defines basic Flag and Flags data structures.
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"""
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import collections
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Flag = collections.namedtuple("Flag", ["name", "bit"])
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class Flags(collections.MutableSet):
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"""
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A simple MutableSet implementation that will only accept known flags as elements.
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Will behave like a regular set(), except that a ValueError will be thrown when .add()ing
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unexpected flags.
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"""
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def __init__(self, defined_flags):
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self._valid_flags = set(flag.name for flag in defined_flags)
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self._flags = set()
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def __contains__(self, x):
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return self._flags.__contains__(x)
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def __iter__(self):
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return self._flags.__iter__()
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def __len__(self):
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return self._flags.__len__()
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def discard(self, value):
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return self._flags.discard(value)
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def add(self, value):
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if value not in self._valid_flags:
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raise ValueError("Unexpected flag: {}".format(value))
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return self._flags.add(value)
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