| ######################## 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 |
