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# coding: utf-8
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"""
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Utilities for dealing with text encodings
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"""
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#-----------------------------------------------------------------------------
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# Copyright (C) 2008-2012 The IPython Development Team
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#
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# Distributed under the terms of the BSD License. The full license is in
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# the file COPYING, distributed as part of this software.
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#-----------------------------------------------------------------------------
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#-----------------------------------------------------------------------------
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# Imports
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#-----------------------------------------------------------------------------
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import sys
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import locale
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import warnings
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# to deal with the possibility of sys.std* not being a stream at all
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def get_stream_enc(stream, default=None):
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"""Return the given stream's encoding or a default.
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There are cases where ``sys.std*`` might not actually be a stream, so
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check for the encoding attribute prior to returning it, and return
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a default if it doesn't exist or evaluates as False. ``default``
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is None if not provided.
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"""
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if not hasattr(stream, 'encoding') or not stream.encoding:
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return default
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else:
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return stream.encoding
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# Less conservative replacement for sys.getdefaultencoding, that will try
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# to match the environment.
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# Defined here as central function, so if we find better choices, we
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# won't need to make changes all over IPython.
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def getdefaultencoding(prefer_stream=True):
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"""Return IPython's guess for the default encoding for bytes as text.
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If prefer_stream is True (default), asks for stdin.encoding first,
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to match the calling Terminal, but that is often None for subprocesses.
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Then fall back on locale.getpreferredencoding(),
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which should be a sensible platform default (that respects LANG environment),
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and finally to sys.getdefaultencoding() which is the most conservative option,
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and usually UTF8 as of Python 3.
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"""
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enc = None
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if prefer_stream:
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enc = get_stream_enc(sys.stdin)
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if not enc or enc=='ascii':
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try:
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# There are reports of getpreferredencoding raising errors
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# in some cases, which may well be fixed, but let's be conservative here.
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enc = locale.getpreferredencoding()
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except Exception:
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pass
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enc = enc or sys.getdefaultencoding()
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# On windows `cp0` can be returned to indicate that there is no code page.
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# Since cp0 is an invalid encoding return instead cp1252 which is the
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# Western European default.
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if enc == 'cp0':
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warnings.warn(
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"Invalid code page cp0 detected - using cp1252 instead."
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"If cp1252 is incorrect please ensure a valid code page "
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"is defined for the process.", RuntimeWarning)
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return 'cp1252'
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return enc
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DEFAULT_ENCODING = getdefaultencoding()
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