This file is indexed.

/usr/lib/pypy/dist-packages/bs4/dammit.py is in pypy-bs4 4.6.0-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
# -*- coding: utf-8 -*-
"""Beautiful Soup bonus library: Unicode, Dammit

This library converts a bytestream to Unicode through any means
necessary. It is heavily based on code from Mark Pilgrim's Universal
Feed Parser. It works best on XML and HTML, but it does not rewrite the
XML or HTML to reflect a new encoding; that's the tree builder's job.
"""
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
__license__ = "MIT"

import codecs
from htmlentitydefs import codepoint2name
import re
import logging
import string

# Import a library to autodetect character encodings.
chardet_type = None
try:
    # First try the fast C implementation.
    #  PyPI package: cchardet
    import cchardet
    def chardet_dammit(s):
        return cchardet.detect(s)['encoding']
except ImportError:
    try:
        # Fall back to the pure Python implementation
        #  Debian package: python-chardet
        #  PyPI package: chardet
        import chardet
        def chardet_dammit(s):
            return chardet.detect(s)['encoding']
        #import chardet.constants
        #chardet.constants._debug = 1
    except ImportError:
        # No chardet available.
        def chardet_dammit(s):
            return None

# Available from http://cjkpython.i18n.org/.
try:
    import iconv_codec
except ImportError:
    pass

xml_encoding_re = re.compile(
    '^<\?.*encoding=[\'"](.*?)[\'"].*\?>'.encode(), re.I)
html_meta_re = re.compile(
    '<\s*meta[^>]+charset\s*=\s*["\']?([^>]*?)[ /;\'">]'.encode(), re.I)

class EntitySubstitution(object):

    """Substitute XML or HTML entities for the corresponding characters."""

    def _populate_class_variables():
        lookup = {}
        reverse_lookup = {}
        characters_for_re = []
        for codepoint, name in list(codepoint2name.items()):
            character = unichr(codepoint)
            if codepoint != 34:
                # There's no point in turning the quotation mark into
                # &quot;, unless it happens within an attribute value, which
                # is handled elsewhere.
                characters_for_re.append(character)
                lookup[character] = name
            # But we do want to turn &quot; into the quotation mark.
            reverse_lookup[name] = character
        re_definition = "[%s]" % "".join(characters_for_re)
        return lookup, reverse_lookup, re.compile(re_definition)
    (CHARACTER_TO_HTML_ENTITY, HTML_ENTITY_TO_CHARACTER,
     CHARACTER_TO_HTML_ENTITY_RE) = _populate_class_variables()

    CHARACTER_TO_XML_ENTITY = {
        "'": "apos",
        '"': "quot",
        "&": "amp",
        "<": "lt",
        ">": "gt",
        }

    BARE_AMPERSAND_OR_BRACKET = re.compile("([<>]|"
                                           "&(?!#\d+;|#x[0-9a-fA-F]+;|\w+;)"
                                           ")")

    AMPERSAND_OR_BRACKET = re.compile("([<>&])")

    @classmethod
    def _substitute_html_entity(cls, matchobj):
        entity = cls.CHARACTER_TO_HTML_ENTITY.get(matchobj.group(0))
        return "&%s;" % entity

    @classmethod
    def _substitute_xml_entity(cls, matchobj):
        """Used with a regular expression to substitute the
        appropriate XML entity for an XML special character."""
        entity = cls.CHARACTER_TO_XML_ENTITY[matchobj.group(0)]
        return "&%s;" % entity

    @classmethod
    def quoted_attribute_value(self, value):
        """Make a value into a quoted XML attribute, possibly escaping it.

         Most strings will be quoted using double quotes.

          Bob's Bar -> "Bob's Bar"

         If a string contains double quotes, it will be quoted using
         single quotes.

          Welcome to "my bar" -> 'Welcome to "my bar"'

         If a string contains both single and double quotes, the
         double quotes will be escaped, and the string will be quoted
         using double quotes.

          Welcome to "Bob's Bar" -> "Welcome to &quot;Bob's bar&quot;
        """
        quote_with = '"'
        if '"' in value:
            if "'" in value:
                # The string contains both single and double
                # quotes.  Turn the double quotes into
                # entities. We quote the double quotes rather than
                # the single quotes because the entity name is
                # "&quot;" whether this is HTML or XML.  If we
                # quoted the single quotes, we'd have to decide
                # between &apos; and &squot;.
                replace_with = "&quot;"
                value = value.replace('"', replace_with)
            else:
                # There are double quotes but no single quotes.
                # We can use single quotes to quote the attribute.
                quote_with = "'"
        return quote_with + value + quote_with

    @classmethod
    def substitute_xml(cls, value, make_quoted_attribute=False):
        """Substitute XML entities for special XML characters.

        :param value: A string to be substituted. The less-than sign
          will become &lt;, the greater-than sign will become &gt;,
          and any ampersands will become &amp;. If you want ampersands
          that appear to be part of an entity definition to be left
          alone, use substitute_xml_containing_entities() instead.

        :param make_quoted_attribute: If True, then the string will be
         quoted, as befits an attribute value.
        """
        # Escape angle brackets and ampersands.
        value = cls.AMPERSAND_OR_BRACKET.sub(
            cls._substitute_xml_entity, value)

        if make_quoted_attribute:
            value = cls.quoted_attribute_value(value)
        return value

    @classmethod
    def substitute_xml_containing_entities(
        cls, value, make_quoted_attribute=False):
        """Substitute XML entities for special XML characters.

        :param value: A string to be substituted. The less-than sign will
          become &lt;, the greater-than sign will become &gt;, and any
          ampersands that are not part of an entity defition will
          become &amp;.

        :param make_quoted_attribute: If True, then the string will be
         quoted, as befits an attribute value.
        """
        # Escape angle brackets, and ampersands that aren't part of
        # entities.
        value = cls.BARE_AMPERSAND_OR_BRACKET.sub(
            cls._substitute_xml_entity, value)

        if make_quoted_attribute:
            value = cls.quoted_attribute_value(value)
        return value

    @classmethod
    def substitute_html(cls, s):
        """Replace certain Unicode characters with named HTML entities.

        This differs from data.encode(encoding, 'xmlcharrefreplace')
        in that the goal is to make the result more readable (to those
        with ASCII displays) rather than to recover from
        errors. There's absolutely nothing wrong with a UTF-8 string
        containg a LATIN SMALL LETTER E WITH ACUTE, but replacing that
        character with "&eacute;" will make it more readable to some
        people.
        """
        return cls.CHARACTER_TO_HTML_ENTITY_RE.sub(
            cls._substitute_html_entity, s)


class EncodingDetector:
    """Suggests a number of possible encodings for a bytestring.

    Order of precedence:

    1. Encodings you specifically tell EncodingDetector to try first
    (the override_encodings argument to the constructor).

    2. An encoding declared within the bytestring itself, either in an
    XML declaration (if the bytestring is to be interpreted as an XML
    document), or in a <meta> tag (if the bytestring is to be
    interpreted as an HTML document.)

    3. An encoding detected through textual analysis by chardet,
    cchardet, or a similar external library.

    4. UTF-8.

    5. Windows-1252.
    """
    def __init__(self, markup, override_encodings=None, is_html=False,
                 exclude_encodings=None):
        self.override_encodings = override_encodings or []
        exclude_encodings = exclude_encodings or []
        self.exclude_encodings = set([x.lower() for x in exclude_encodings])
        self.chardet_encoding = None
        self.is_html = is_html
        self.declared_encoding = None

        # First order of business: strip a byte-order mark.
        self.markup, self.sniffed_encoding = self.strip_byte_order_mark(markup)

    def _usable(self, encoding, tried):
        if encoding is not None:
            encoding = encoding.lower()
            if encoding in self.exclude_encodings:
                return False
            if encoding not in tried:
                tried.add(encoding)
                return True
        return False

    @property
    def encodings(self):
        """Yield a number of encodings that might work for this markup."""
        tried = set()
        for e in self.override_encodings:
            if self._usable(e, tried):
                yield e

        # Did the document originally start with a byte-order mark
        # that indicated its encoding?
        if self._usable(self.sniffed_encoding, tried):
            yield self.sniffed_encoding

        # Look within the document for an XML or HTML encoding
        # declaration.
        if self.declared_encoding is None:
            self.declared_encoding = self.find_declared_encoding(
                self.markup, self.is_html)
        if self._usable(self.declared_encoding, tried):
            yield self.declared_encoding

        # Use third-party character set detection to guess at the
        # encoding.
        if self.chardet_encoding is None:
            self.chardet_encoding = chardet_dammit(self.markup)
        if self._usable(self.chardet_encoding, tried):
            yield self.chardet_encoding

        # As a last-ditch effort, try utf-8 and windows-1252.
        for e in ('utf-8', 'windows-1252'):
            if self._usable(e, tried):
                yield e

    @classmethod
    def strip_byte_order_mark(cls, data):
        """If a byte-order mark is present, strip it and return the encoding it implies."""
        encoding = None
        if isinstance(data, unicode):
            # Unicode data cannot have a byte-order mark.
            return data, encoding
        if (len(data) >= 4) and (data[:2] == b'\xfe\xff') \
               and (data[2:4] != '\x00\x00'):
            encoding = 'utf-16be'
            data = data[2:]
        elif (len(data) >= 4) and (data[:2] == b'\xff\xfe') \
                 and (data[2:4] != '\x00\x00'):
            encoding = 'utf-16le'
            data = data[2:]
        elif data[:3] == b'\xef\xbb\xbf':
            encoding = 'utf-8'
            data = data[3:]
        elif data[:4] == b'\x00\x00\xfe\xff':
            encoding = 'utf-32be'
            data = data[4:]
        elif data[:4] == b'\xff\xfe\x00\x00':
            encoding = 'utf-32le'
            data = data[4:]
        return data, encoding

    @classmethod
    def find_declared_encoding(cls, markup, is_html=False, search_entire_document=False):
        """Given a document, tries to find its declared encoding.

        An XML encoding is declared at the beginning of the document.

        An HTML encoding is declared in a <meta> tag, hopefully near the
        beginning of the document.
        """
        if search_entire_document:
            xml_endpos = html_endpos = len(markup)
        else:
            xml_endpos = 1024
            html_endpos = max(2048, int(len(markup) * 0.05))

        declared_encoding = None
        declared_encoding_match = xml_encoding_re.search(markup, endpos=xml_endpos)
        if not declared_encoding_match and is_html:
            declared_encoding_match = html_meta_re.search(markup, endpos=html_endpos)
        if declared_encoding_match is not None:
            declared_encoding = declared_encoding_match.groups()[0].decode(
                'ascii', 'replace')
        if declared_encoding:
            return declared_encoding.lower()
        return None

class UnicodeDammit:
    """A class for detecting the encoding of a *ML document and
    converting it to a Unicode string. If the source encoding is
    windows-1252, can replace MS smart quotes with their HTML or XML
    equivalents."""

    # This dictionary maps commonly seen values for "charset" in HTML
    # meta tags to the corresponding Python codec names. It only covers
    # values that aren't in Python's aliases and can't be determined
    # by the heuristics in find_codec.
    CHARSET_ALIASES = {"macintosh": "mac-roman",
                       "x-sjis": "shift-jis"}

    ENCODINGS_WITH_SMART_QUOTES = [
        "windows-1252",
        "iso-8859-1",
        "iso-8859-2",
        ]

    def __init__(self, markup, override_encodings=[],
                 smart_quotes_to=None, is_html=False, exclude_encodings=[]):
        self.smart_quotes_to = smart_quotes_to
        self.tried_encodings = []
        self.contains_replacement_characters = False
        self.is_html = is_html
        self.log = logging.getLogger(__name__)
        self.detector = EncodingDetector(
            markup, override_encodings, is_html, exclude_encodings)

        # Short-circuit if the data is in Unicode to begin with.
        if isinstance(markup, unicode) or markup == '':
            self.markup = markup
            self.unicode_markup = unicode(markup)
            self.original_encoding = None
            return

        # The encoding detector may have stripped a byte-order mark.
        # Use the stripped markup from this point on.
        self.markup = self.detector.markup

        u = None
        for encoding in self.detector.encodings:
            markup = self.detector.markup
            u = self._convert_from(encoding)
            if u is not None:
                break

        if not u:
            # None of the encodings worked. As an absolute last resort,
            # try them again with character replacement.

            for encoding in self.detector.encodings:
                if encoding != "ascii":
                    u = self._convert_from(encoding, "replace")
                if u is not None:
                    self.log.warning(
                            "Some characters could not be decoded, and were "
                            "replaced with REPLACEMENT CHARACTER."
                    )
                    self.contains_replacement_characters = True
                    break

        # If none of that worked, we could at this point force it to
        # ASCII, but that would destroy so much data that I think
        # giving up is better.
        self.unicode_markup = u
        if not u:
            self.original_encoding = None

    def _sub_ms_char(self, match):
        """Changes a MS smart quote character to an XML or HTML
        entity, or an ASCII character."""
        orig = match.group(1)
        if self.smart_quotes_to == 'ascii':
            sub = self.MS_CHARS_TO_ASCII.get(orig).encode()
        else:
            sub = self.MS_CHARS.get(orig)
            if type(sub) == tuple:
                if self.smart_quotes_to == 'xml':
                    sub = '&#x'.encode() + sub[1].encode() + ';'.encode()
                else:
                    sub = '&'.encode() + sub[0].encode() + ';'.encode()
            else:
                sub = sub.encode()
        return sub

    def _convert_from(self, proposed, errors="strict"):
        proposed = self.find_codec(proposed)
        if not proposed or (proposed, errors) in self.tried_encodings:
            return None
        self.tried_encodings.append((proposed, errors))
        markup = self.markup
        # Convert smart quotes to HTML if coming from an encoding
        # that might have them.
        if (self.smart_quotes_to is not None
            and proposed in self.ENCODINGS_WITH_SMART_QUOTES):
            smart_quotes_re = b"([\x80-\x9f])"
            smart_quotes_compiled = re.compile(smart_quotes_re)
            markup = smart_quotes_compiled.sub(self._sub_ms_char, markup)

        try:
            #print "Trying to convert document to %s (errors=%s)" % (
            #    proposed, errors)
            u = self._to_unicode(markup, proposed, errors)
            self.markup = u
            self.original_encoding = proposed
        except Exception as e:
            #print "That didn't work!"
            #print e
            return None
        #print "Correct encoding: %s" % proposed
        return self.markup

    def _to_unicode(self, data, encoding, errors="strict"):
        '''Given a string and its encoding, decodes the string into Unicode.
        %encoding is a string recognized by encodings.aliases'''
        return unicode(data, encoding, errors)

    @property
    def declared_html_encoding(self):
        if not self.is_html:
            return None
        return self.detector.declared_encoding

    def find_codec(self, charset):
        value = (self._codec(self.CHARSET_ALIASES.get(charset, charset))
               or (charset and self._codec(charset.replace("-", "")))
               or (charset and self._codec(charset.replace("-", "_")))
               or (charset and charset.lower())
               or charset
                )
        if value:
            return value.lower()
        return None

    def _codec(self, charset):
        if not charset:
            return charset
        codec = None
        try:
            codecs.lookup(charset)
            codec = charset
        except (LookupError, ValueError):
            pass
        return codec


    # A partial mapping of ISO-Latin-1 to HTML entities/XML numeric entities.
    MS_CHARS = {b'\x80': ('euro', '20AC'),
                b'\x81': ' ',
                b'\x82': ('sbquo', '201A'),
                b'\x83': ('fnof', '192'),
                b'\x84': ('bdquo', '201E'),
                b'\x85': ('hellip', '2026'),
                b'\x86': ('dagger', '2020'),
                b'\x87': ('Dagger', '2021'),
                b'\x88': ('circ', '2C6'),
                b'\x89': ('permil', '2030'),
                b'\x8A': ('Scaron', '160'),
                b'\x8B': ('lsaquo', '2039'),
                b'\x8C': ('OElig', '152'),
                b'\x8D': '?',
                b'\x8E': ('#x17D', '17D'),
                b'\x8F': '?',
                b'\x90': '?',
                b'\x91': ('lsquo', '2018'),
                b'\x92': ('rsquo', '2019'),
                b'\x93': ('ldquo', '201C'),
                b'\x94': ('rdquo', '201D'),
                b'\x95': ('bull', '2022'),
                b'\x96': ('ndash', '2013'),
                b'\x97': ('mdash', '2014'),
                b'\x98': ('tilde', '2DC'),
                b'\x99': ('trade', '2122'),
                b'\x9a': ('scaron', '161'),
                b'\x9b': ('rsaquo', '203A'),
                b'\x9c': ('oelig', '153'),
                b'\x9d': '?',
                b'\x9e': ('#x17E', '17E'),
                b'\x9f': ('Yuml', ''),}

    # A parochial partial mapping of ISO-Latin-1 to ASCII. Contains
    # horrors like stripping diacritical marks to turn á into a, but also
    # contains non-horrors like turning “ into ".
    MS_CHARS_TO_ASCII = {
        b'\x80' : 'EUR',
        b'\x81' : ' ',
        b'\x82' : ',',
        b'\x83' : 'f',
        b'\x84' : ',,',
        b'\x85' : '...',
        b'\x86' : '+',
        b'\x87' : '++',
        b'\x88' : '^',
        b'\x89' : '%',
        b'\x8a' : 'S',
        b'\x8b' : '<',
        b'\x8c' : 'OE',
        b'\x8d' : '?',
        b'\x8e' : 'Z',
        b'\x8f' : '?',
        b'\x90' : '?',
        b'\x91' : "'",
        b'\x92' : "'",
        b'\x93' : '"',
        b'\x94' : '"',
        b'\x95' : '*',
        b'\x96' : '-',
        b'\x97' : '--',
        b'\x98' : '~',
        b'\x99' : '(TM)',
        b'\x9a' : 's',
        b'\x9b' : '>',
        b'\x9c' : 'oe',
        b'\x9d' : '?',
        b'\x9e' : 'z',
        b'\x9f' : 'Y',
        b'\xa0' : ' ',
        b'\xa1' : '!',
        b'\xa2' : 'c',
        b'\xa3' : 'GBP',
        b'\xa4' : '$', #This approximation is especially parochial--this is the
                       #generic currency symbol.
        b'\xa5' : 'YEN',
        b'\xa6' : '|',
        b'\xa7' : 'S',
        b'\xa8' : '..',
        b'\xa9' : '',
        b'\xaa' : '(th)',
        b'\xab' : '<<',
        b'\xac' : '!',
        b'\xad' : ' ',
        b'\xae' : '(R)',
        b'\xaf' : '-',
        b'\xb0' : 'o',
        b'\xb1' : '+-',
        b'\xb2' : '2',
        b'\xb3' : '3',
        b'\xb4' : ("'", 'acute'),
        b'\xb5' : 'u',
        b'\xb6' : 'P',
        b'\xb7' : '*',
        b'\xb8' : ',',
        b'\xb9' : '1',
        b'\xba' : '(th)',
        b'\xbb' : '>>',
        b'\xbc' : '1/4',
        b'\xbd' : '1/2',
        b'\xbe' : '3/4',
        b'\xbf' : '?',
        b'\xc0' : 'A',
        b'\xc1' : 'A',
        b'\xc2' : 'A',
        b'\xc3' : 'A',
        b'\xc4' : 'A',
        b'\xc5' : 'A',
        b'\xc6' : 'AE',
        b'\xc7' : 'C',
        b'\xc8' : 'E',
        b'\xc9' : 'E',
        b'\xca' : 'E',
        b'\xcb' : 'E',
        b'\xcc' : 'I',
        b'\xcd' : 'I',
        b'\xce' : 'I',
        b'\xcf' : 'I',
        b'\xd0' : 'D',
        b'\xd1' : 'N',
        b'\xd2' : 'O',
        b'\xd3' : 'O',
        b'\xd4' : 'O',
        b'\xd5' : 'O',
        b'\xd6' : 'O',
        b'\xd7' : '*',
        b'\xd8' : 'O',
        b'\xd9' : 'U',
        b'\xda' : 'U',
        b'\xdb' : 'U',
        b'\xdc' : 'U',
        b'\xdd' : 'Y',
        b'\xde' : 'b',
        b'\xdf' : 'B',
        b'\xe0' : 'a',
        b'\xe1' : 'a',
        b'\xe2' : 'a',
        b'\xe3' : 'a',
        b'\xe4' : 'a',
        b'\xe5' : 'a',
        b'\xe6' : 'ae',
        b'\xe7' : 'c',
        b'\xe8' : 'e',
        b'\xe9' : 'e',
        b'\xea' : 'e',
        b'\xeb' : 'e',
        b'\xec' : 'i',
        b'\xed' : 'i',
        b'\xee' : 'i',
        b'\xef' : 'i',
        b'\xf0' : 'o',
        b'\xf1' : 'n',
        b'\xf2' : 'o',
        b'\xf3' : 'o',
        b'\xf4' : 'o',
        b'\xf5' : 'o',
        b'\xf6' : 'o',
        b'\xf7' : '/',
        b'\xf8' : 'o',
        b'\xf9' : 'u',
        b'\xfa' : 'u',
        b'\xfb' : 'u',
        b'\xfc' : 'u',
        b'\xfd' : 'y',
        b'\xfe' : 'b',
        b'\xff' : 'y',
        }

    # A map used when removing rogue Windows-1252/ISO-8859-1
    # characters in otherwise UTF-8 documents.
    #
    # Note that \x81, \x8d, \x8f, \x90, and \x9d are undefined in
    # Windows-1252.
    WINDOWS_1252_TO_UTF8 = {
        0x80 : b'\xe2\x82\xac', # €
        0x82 : b'\xe2\x80\x9a', # ‚
        0x83 : b'\xc6\x92',     # ƒ
        0x84 : b'\xe2\x80\x9e', # „
        0x85 : b'\xe2\x80\xa6', # …
        0x86 : b'\xe2\x80\xa0', # †
        0x87 : b'\xe2\x80\xa1', # ‡
        0x88 : b'\xcb\x86',     # ˆ
        0x89 : b'\xe2\x80\xb0', # ‰
        0x8a : b'\xc5\xa0',     # Š
        0x8b : b'\xe2\x80\xb9', # ‹
        0x8c : b'\xc5\x92',     # Œ
        0x8e : b'\xc5\xbd',     # Ž
        0x91 : b'\xe2\x80\x98', # ‘
        0x92 : b'\xe2\x80\x99', # ’
        0x93 : b'\xe2\x80\x9c', # “
        0x94 : b'\xe2\x80\x9d', # ”
        0x95 : b'\xe2\x80\xa2', # •
        0x96 : b'\xe2\x80\x93', # –
        0x97 : b'\xe2\x80\x94', # —
        0x98 : b'\xcb\x9c',     # ˜
        0x99 : b'\xe2\x84\xa2', # ™
        0x9a : b'\xc5\xa1',     # š
        0x9b : b'\xe2\x80\xba', # ›
        0x9c : b'\xc5\x93',     # œ
        0x9e : b'\xc5\xbe',     # ž
        0x9f : b'\xc5\xb8',     # Ÿ
        0xa0 : b'\xc2\xa0',     #  
        0xa1 : b'\xc2\xa1',     # ¡
        0xa2 : b'\xc2\xa2',     # ¢
        0xa3 : b'\xc2\xa3',     # £
        0xa4 : b'\xc2\xa4',     # ¤
        0xa5 : b'\xc2\xa5',     # ¥
        0xa6 : b'\xc2\xa6',     # ¦
        0xa7 : b'\xc2\xa7',     # §
        0xa8 : b'\xc2\xa8',     # ¨
        0xa9 : b'\xc2\xa9',     # ©
        0xaa : b'\xc2\xaa',     # ª
        0xab : b'\xc2\xab',     # «
        0xac : b'\xc2\xac',     # ¬
        0xad : b'\xc2\xad',     # ­
        0xae : b'\xc2\xae',     # ®
        0xaf : b'\xc2\xaf',     # ¯
        0xb0 : b'\xc2\xb0',     # °
        0xb1 : b'\xc2\xb1',     # ±
        0xb2 : b'\xc2\xb2',     # ²
        0xb3 : b'\xc2\xb3',     # ³
        0xb4 : b'\xc2\xb4',     # ´
        0xb5 : b'\xc2\xb5',     # µ
        0xb6 : b'\xc2\xb6',     # ¶
        0xb7 : b'\xc2\xb7',     # ·
        0xb8 : b'\xc2\xb8',     # ¸
        0xb9 : b'\xc2\xb9',     # ¹
        0xba : b'\xc2\xba',     # º
        0xbb : b'\xc2\xbb',     # »
        0xbc : b'\xc2\xbc',     # ¼
        0xbd : b'\xc2\xbd',     # ½
        0xbe : b'\xc2\xbe',     # ¾
        0xbf : b'\xc2\xbf',     # ¿
        0xc0 : b'\xc3\x80',     # À
        0xc1 : b'\xc3\x81',     # Á
        0xc2 : b'\xc3\x82',     # Â
        0xc3 : b'\xc3\x83',     # Ã
        0xc4 : b'\xc3\x84',     # Ä
        0xc5 : b'\xc3\x85',     # Å
        0xc6 : b'\xc3\x86',     # Æ
        0xc7 : b'\xc3\x87',     # Ç
        0xc8 : b'\xc3\x88',     # È
        0xc9 : b'\xc3\x89',     # É
        0xca : b'\xc3\x8a',     # Ê
        0xcb : b'\xc3\x8b',     # Ë
        0xcc : b'\xc3\x8c',     # Ì
        0xcd : b'\xc3\x8d',     # Í
        0xce : b'\xc3\x8e',     # Î
        0xcf : b'\xc3\x8f',     # Ï
        0xd0 : b'\xc3\x90',     # Ð
        0xd1 : b'\xc3\x91',     # Ñ
        0xd2 : b'\xc3\x92',     # Ò
        0xd3 : b'\xc3\x93',     # Ó
        0xd4 : b'\xc3\x94',     # Ô
        0xd5 : b'\xc3\x95',     # Õ
        0xd6 : b'\xc3\x96',     # Ö
        0xd7 : b'\xc3\x97',     # ×
        0xd8 : b'\xc3\x98',     # Ø
        0xd9 : b'\xc3\x99',     # Ù
        0xda : b'\xc3\x9a',     # Ú
        0xdb : b'\xc3\x9b',     # Û
        0xdc : b'\xc3\x9c',     # Ü
        0xdd : b'\xc3\x9d',     # Ý
        0xde : b'\xc3\x9e',     # Þ
        0xdf : b'\xc3\x9f',     # ß
        0xe0 : b'\xc3\xa0',     # à
        0xe1 : b'\xa1',         # á
        0xe2 : b'\xc3\xa2',     # â
        0xe3 : b'\xc3\xa3',     # ã
        0xe4 : b'\xc3\xa4',     # ä
        0xe5 : b'\xc3\xa5',     # å
        0xe6 : b'\xc3\xa6',     # æ
        0xe7 : b'\xc3\xa7',     # ç
        0xe8 : b'\xc3\xa8',     # è
        0xe9 : b'\xc3\xa9',     # é
        0xea : b'\xc3\xaa',     # ê
        0xeb : b'\xc3\xab',     # ë
        0xec : b'\xc3\xac',     # ì
        0xed : b'\xc3\xad',     # í
        0xee : b'\xc3\xae',     # î
        0xef : b'\xc3\xaf',     # ï
        0xf0 : b'\xc3\xb0',     # ð
        0xf1 : b'\xc3\xb1',     # ñ
        0xf2 : b'\xc3\xb2',     # ò
        0xf3 : b'\xc3\xb3',     # ó
        0xf4 : b'\xc3\xb4',     # ô
        0xf5 : b'\xc3\xb5',     # õ
        0xf6 : b'\xc3\xb6',     # ö
        0xf7 : b'\xc3\xb7',     # ÷
        0xf8 : b'\xc3\xb8',     # ø
        0xf9 : b'\xc3\xb9',     # ù
        0xfa : b'\xc3\xba',     # ú
        0xfb : b'\xc3\xbb',     # û
        0xfc : b'\xc3\xbc',     # ü
        0xfd : b'\xc3\xbd',     # ý
        0xfe : b'\xc3\xbe',     # þ
        }

    MULTIBYTE_MARKERS_AND_SIZES = [
        (0xc2, 0xdf, 2), # 2-byte characters start with a byte C2-DF
        (0xe0, 0xef, 3), # 3-byte characters start with E0-EF
        (0xf0, 0xf4, 4), # 4-byte characters start with F0-F4
        ]

    FIRST_MULTIBYTE_MARKER = MULTIBYTE_MARKERS_AND_SIZES[0][0]
    LAST_MULTIBYTE_MARKER = MULTIBYTE_MARKERS_AND_SIZES[-1][1]

    @classmethod
    def detwingle(cls, in_bytes, main_encoding="utf8",
                  embedded_encoding="windows-1252"):
        """Fix characters from one encoding embedded in some other encoding.

        Currently the only situation supported is Windows-1252 (or its
        subset ISO-8859-1), embedded in UTF-8.

        The input must be a bytestring. If you've already converted
        the document to Unicode, you're too late.

        The output is a bytestring in which `embedded_encoding`
        characters have been converted to their `main_encoding`
        equivalents.
        """
        if embedded_encoding.replace('_', '-').lower() not in (
            'windows-1252', 'windows_1252'):
            raise NotImplementedError(
                "Windows-1252 and ISO-8859-1 are the only currently supported "
                "embedded encodings.")

        if main_encoding.lower() not in ('utf8', 'utf-8'):
            raise NotImplementedError(
                "UTF-8 is the only currently supported main encoding.")

        byte_chunks = []

        chunk_start = 0
        pos = 0
        while pos < len(in_bytes):
            byte = in_bytes[pos]
            if not isinstance(byte, int):
                # Python 2.x
                byte = ord(byte)
            if (byte >= cls.FIRST_MULTIBYTE_MARKER
                and byte <= cls.LAST_MULTIBYTE_MARKER):
                # This is the start of a UTF-8 multibyte character. Skip
                # to the end.
                for start, end, size in cls.MULTIBYTE_MARKERS_AND_SIZES:
                    if byte >= start and byte <= end:
                        pos += size
                        break
            elif byte >= 0x80 and byte in cls.WINDOWS_1252_TO_UTF8:
                # We found a Windows-1252 character!
                # Save the string up to this point as a chunk.
                byte_chunks.append(in_bytes[chunk_start:pos])

                # Now translate the Windows-1252 character into UTF-8
                # and add it as another, one-byte chunk.
                byte_chunks.append(cls.WINDOWS_1252_TO_UTF8[byte])
                pos += 1
                chunk_start = pos
            else:
                # Go on to the next character.
                pos += 1
        if chunk_start == 0:
            # The string is unchanged.
            return in_bytes
        else:
            # Store the final chunk.
            byte_chunks.append(in_bytes[chunk_start:])
        return b''.join(byte_chunks)