104 lines
3.0 KiB
Python
104 lines
3.0 KiB
Python
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# -*- coding: utf-8 -*-
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# vi:tabstop=4:expandtab:sw=4
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"""Transliterate Unicode text into plain 7-bit ASCII.
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Example usage:
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>>> from unidecode import unidecode
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>>> unidecode(u"\u5317\u4EB0")
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"Bei Jing "
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The transliteration uses a straightforward map, and doesn't have alternatives
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for the same character based on language, position, or anything else.
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In Python 3, a standard string object will be returned. If you need bytes, use:
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>>> unidecode("Κνωσός").encode("ascii")
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b'Knosos'
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"""
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import warnings
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from sys import version_info
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Cache = {}
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def _warn_if_not_unicode(string):
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if version_info[0] < 3 and not isinstance(string, unicode):
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warnings.warn( "Argument %r is not an unicode object. "
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"Passing an encoded string will likely have "
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"unexpected results." % (type(string),),
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RuntimeWarning, 2)
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def unidecode_expect_ascii(string):
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"""Transliterate an Unicode object into an ASCII string
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>>> unidecode(u"\u5317\u4EB0")
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"Bei Jing "
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This function first tries to convert the string using ASCII codec.
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If it fails (because of non-ASCII characters), it falls back to
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transliteration using the character tables.
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This is approx. five times faster if the string only contains ASCII
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characters, but slightly slower than using unidecode directly if non-ASCII
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chars are present.
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"""
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_warn_if_not_unicode(string)
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try:
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bytestring = string.encode('ASCII')
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except UnicodeEncodeError:
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return _unidecode(string)
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if version_info[0] >= 3:
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return string
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else:
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return bytestring
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def unidecode_expect_nonascii(string):
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"""Transliterate an Unicode object into an ASCII string
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>>> unidecode(u"\u5317\u4EB0")
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"Bei Jing "
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"""
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_warn_if_not_unicode(string)
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return _unidecode(string)
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unidecode = unidecode_expect_ascii
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def _unidecode(string):
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retval = []
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for char in string:
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codepoint = ord(char)
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if codepoint < 0x80: # Basic ASCII
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retval.append(str(char))
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continue
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if codepoint > 0xeffff:
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continue # Characters in Private Use Area and above are ignored
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if 0xd800 <= codepoint <= 0xdfff:
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warnings.warn( "Surrogate character %r will be ignored. "
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"You might be using a narrow Python build." % (char,),
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RuntimeWarning, 2)
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section = codepoint >> 8 # Chop off the last two hex digits
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position = codepoint % 256 # Last two hex digits
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try:
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table = Cache[section]
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except KeyError:
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try:
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mod = __import__('unidecode.x%03x'%(section), globals(), locals(), ['data'])
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except ImportError:
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Cache[section] = None
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continue # No match: ignore this character and carry on.
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Cache[section] = table = mod.data
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if table and len(table) > position:
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retval.append( table[position] )
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return ''.join(retval)
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