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| ######################## BEGIN LICENSE BLOCK ########################
| # This code was modified from latin1prober.py by Rob Speer <rob@lumino.so>.
| # The Original Code is Mozilla Universal charset detector code.
| #
| # The Initial Developer of the Original Code is
| # Netscape Communications Corporation.
| # Portions created by the Initial Developer are Copyright (C) 2001
| # the Initial Developer. All Rights Reserved.
| #
| # Contributor(s):
| # Rob Speer - adapt to MacRoman encoding
| # Mark Pilgrim - port to Python
| # Shy Shalom - original C code
| #
| # This library is free software; you can redistribute it and/or
| # modify it under the terms of the GNU Lesser General Public
| # License as published by the Free Software Foundation; either
| # version 2.1 of the License, or (at your option) any later version.
| #
| # This library is distributed in the hope that it will be useful,
| # but WITHOUT ANY WARRANTY; without even the implied warranty of
| # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
| # Lesser General Public License for more details.
| #
| # You should have received a copy of the GNU Lesser General Public
| # License along with this library; if not, write to the Free Software
| # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
| # 02110-1301 USA
| ######################### END LICENSE BLOCK #########################
|
| from typing import List, Union
|
| from .charsetprober import CharSetProber
| from .enums import ProbingState
|
| FREQ_CAT_NUM = 4
|
| UDF = 0 # undefined
| OTH = 1 # other
| ASC = 2 # ascii capital letter
| ASS = 3 # ascii small letter
| ACV = 4 # accent capital vowel
| ACO = 5 # accent capital other
| ASV = 6 # accent small vowel
| ASO = 7 # accent small other
| ODD = 8 # character that is unlikely to appear
| CLASS_NUM = 9 # total classes
|
| # The change from Latin1 is that we explicitly look for extended characters
| # that are infrequently-occurring symbols, and consider them to always be
| # improbable. This should let MacRoman get out of the way of more likely
| # encodings in most situations.
|
| # fmt: off
| MacRoman_CharToClass = (
| OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # 00 - 07
| OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # 08 - 0F
| OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # 10 - 17
| OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # 18 - 1F
| OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # 20 - 27
| OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # 28 - 2F
| OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # 30 - 37
| OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # 38 - 3F
| OTH, ASC, ASC, ASC, ASC, ASC, ASC, ASC, # 40 - 47
| ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC, # 48 - 4F
| ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC, # 50 - 57
| ASC, ASC, ASC, OTH, OTH, OTH, OTH, OTH, # 58 - 5F
| OTH, ASS, ASS, ASS, ASS, ASS, ASS, ASS, # 60 - 67
| ASS, ASS, ASS, ASS, ASS, ASS, ASS, ASS, # 68 - 6F
| ASS, ASS, ASS, ASS, ASS, ASS, ASS, ASS, # 70 - 77
| ASS, ASS, ASS, OTH, OTH, OTH, OTH, OTH, # 78 - 7F
| ACV, ACV, ACO, ACV, ACO, ACV, ACV, ASV, # 80 - 87
| ASV, ASV, ASV, ASV, ASV, ASO, ASV, ASV, # 88 - 8F
| ASV, ASV, ASV, ASV, ASV, ASV, ASO, ASV, # 90 - 97
| ASV, ASV, ASV, ASV, ASV, ASV, ASV, ASV, # 98 - 9F
| OTH, OTH, OTH, OTH, OTH, OTH, OTH, ASO, # A0 - A7
| OTH, OTH, ODD, ODD, OTH, OTH, ACV, ACV, # A8 - AF
| OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # B0 - B7
| OTH, OTH, OTH, OTH, OTH, OTH, ASV, ASV, # B8 - BF
| OTH, OTH, ODD, OTH, ODD, OTH, OTH, OTH, # C0 - C7
| OTH, OTH, OTH, ACV, ACV, ACV, ACV, ASV, # C8 - CF
| OTH, OTH, OTH, OTH, OTH, OTH, OTH, ODD, # D0 - D7
| ASV, ACV, ODD, OTH, OTH, OTH, OTH, OTH, # D8 - DF
| OTH, OTH, OTH, OTH, OTH, ACV, ACV, ACV, # E0 - E7
| ACV, ACV, ACV, ACV, ACV, ACV, ACV, ACV, # E8 - EF
| ODD, ACV, ACV, ACV, ACV, ASV, ODD, ODD, # F0 - F7
| ODD, ODD, ODD, ODD, ODD, ODD, ODD, ODD, # F8 - FF
| )
|
| # 0 : illegal
| # 1 : very unlikely
| # 2 : normal
| # 3 : very likely
| MacRomanClassModel = (
| # UDF OTH ASC ASS ACV ACO ASV ASO ODD
| 0, 0, 0, 0, 0, 0, 0, 0, 0, # UDF
| 0, 3, 3, 3, 3, 3, 3, 3, 1, # OTH
| 0, 3, 3, 3, 3, 3, 3, 3, 1, # ASC
| 0, 3, 3, 3, 1, 1, 3, 3, 1, # ASS
| 0, 3, 3, 3, 1, 2, 1, 2, 1, # ACV
| 0, 3, 3, 3, 3, 3, 3, 3, 1, # ACO
| 0, 3, 1, 3, 1, 1, 1, 3, 1, # ASV
| 0, 3, 1, 3, 1, 1, 3, 3, 1, # ASO
| 0, 1, 1, 1, 1, 1, 1, 1, 1, # ODD
| )
| # fmt: on
|
|
| class MacRomanProber(CharSetProber):
| def __init__(self) -> None:
| super().__init__()
| self._last_char_class = OTH
| self._freq_counter: List[int] = []
| self.reset()
|
| def reset(self) -> None:
| self._last_char_class = OTH
| self._freq_counter = [0] * FREQ_CAT_NUM
|
| # express the prior that MacRoman is a somewhat rare encoding;
| # this can be done by starting out in a slightly improbable state
| # that must be overcome
| self._freq_counter[2] = 10
|
| super().reset()
|
| @property
| def charset_name(self) -> str:
| return "MacRoman"
|
| @property
| def language(self) -> str:
| return ""
|
| def feed(self, byte_str: Union[bytes, bytearray]) -> ProbingState:
| byte_str = self.remove_xml_tags(byte_str)
| for c in byte_str:
| char_class = MacRoman_CharToClass[c]
| freq = MacRomanClassModel[(self._last_char_class * CLASS_NUM) + char_class]
| if freq == 0:
| self._state = ProbingState.NOT_ME
| break
| self._freq_counter[freq] += 1
| self._last_char_class = char_class
|
| return self.state
|
| def get_confidence(self) -> float:
| if self.state == ProbingState.NOT_ME:
| return 0.01
|
| total = sum(self._freq_counter)
| confidence = (
| 0.0
| if total < 0.01
| else (self._freq_counter[3] - self._freq_counter[1] * 20.0) / total
| )
| confidence = max(confidence, 0.0)
| # lower the confidence of MacRoman so that other more accurate
| # detector can take priority.
| confidence *= 0.73
| return confidence
|
|
