# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license # Copyright (C) 2003-2017 Nominum, Inc. # # Permission to use, copy, modify, and distribute this software and its # documentation for any purpose with or without fee is hereby granted, # provided that the above copyright notice and this permission notice # appear in all copies. # # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. import enum from typing import Type, TypeVar, Union TIntEnum = TypeVar("TIntEnum", bound="IntEnum") class IntEnum(enum.IntEnum): @classmethod def _missing_(cls, value): cls._check_value(value) val = int.__new__(cls, value) val._name_ = cls._extra_to_text(value, None) or f"{cls._prefix()}{value}" val._value_ = value return val @classmethod def _check_value(cls, value): max = cls._maximum() if not isinstance(value, int): raise TypeError if value < 0 or value > max: name = cls._short_name() raise ValueError(f"{name} must be an int between >= 0 and <= {max}") @classmethod def from_text(cls: Type[TIntEnum], text: str) -> TIntEnum: text = text.upper() try: return cls[text] except KeyError: pass value = cls._extra_from_text(text) if value: return value prefix = cls._prefix() if text.startswith(prefix) and text[len(prefix) :].isdigit(): value = int(text[len(prefix) :]) cls._check_value(value) try: return cls(value) except ValueError: return value raise cls._unknown_exception_class() @classmethod def to_text(cls: Type[TIntEnum], value: int) -> str: cls._check_value(value) try: text = cls(value).name except ValueError: text = None text = cls._extra_to_text(value, text) if text is None: text = f"{cls._prefix()}{value}" return text @classmethod def make(cls: Type[TIntEnum], value: Union[int, str]) -> TIntEnum: """Convert text or a value into an enumerated type, if possible. *value*, the ``int`` or ``str`` to convert. Raises a class-specific exception if a ``str`` is provided that cannot be converted. Raises ``ValueError`` if the value is out of range. Returns an enumeration from the calling class corresponding to the value, if one is defined, or an ``int`` otherwise. """ if isinstance(value, str): return cls.from_text(value) cls._check_value(value) return cls(value) @classmethod def _maximum(cls): raise NotImplementedError # pragma: no cover @classmethod def _short_name(cls): return cls.__name__.lower() @classmethod def _prefix(cls): return "" @classmethod def _extra_from_text(cls, text): # pylint: disable=W0613 return None @classmethod def _extra_to_text(cls, value, current_text): # pylint: disable=W0613 return current_text @classmethod def _unknown_exception_class(cls): return ValueError