mwparserfromhell/mwparserfromhell/smart_list/utils.py

# -*- coding: utf-8  -*-
#
# Copyright (C) 2012-2016 Ben Kurtovic <ben.kurtovic@gmail.com>
#
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# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
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# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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"""
This module contains the :class:`.SmartList` type, as well as its
:class:`._ListProxy` child, which together implement a list whose sublists
reflect changes made to the main list, and vice-versa.
"""

from __future__ import unicode_literals

from sys import maxsize

__all__ = []


def inheritdoc(method):
    """Set __doc__ of *method* to __doc__ of *method* in its parent class.

    Since this is used on :class:`.SmartList`, the "parent class" used is
    ``list``. This function can be used as a decorator.
    """
    method.__doc__ = getattr(list, method.__name__).__doc__
    return method


class _SliceNormalizerMixIn(object):
    """MixIn that provides a private method to normalize slices."""

    def _normalize_slice(self, key, clamp=False):
        """Return a slice equivalent to the input *key*, standardized."""
        if key.start is None:
            start = 0
        else:
            start = (len(self) + key.start) if key.start < 0 else key.start
        if key.stop is None or key.stop == maxsize:
            stop = len(self) if clamp else None
        else:
            stop = (len(self) + key.stop) if key.stop < 0 else key.stop
        return slice(start, stop, key.step or 1)