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- ######################## BEGIN LICENSE BLOCK ########################
- # 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):
- # 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 .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
- CLASS_NUM = 8 # total classes
-
- Latin1_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
- OTH, UDF, OTH, ASO, OTH, OTH, OTH, OTH, # 80 - 87
- OTH, OTH, ACO, OTH, ACO, UDF, ACO, UDF, # 88 - 8F
- UDF, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # 90 - 97
- OTH, OTH, ASO, OTH, ASO, UDF, ASO, ACO, # 98 - 9F
- OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # A0 - A7
- OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # A8 - AF
- OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # B0 - B7
- OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH, # B8 - BF
- ACV, ACV, ACV, ACV, ACV, ACV, ACO, ACO, # C0 - C7
- ACV, ACV, ACV, ACV, ACV, ACV, ACV, ACV, # C8 - CF
- ACO, ACO, ACV, ACV, ACV, ACV, ACV, OTH, # D0 - D7
- ACV, ACV, ACV, ACV, ACV, ACO, ACO, ACO, # D8 - DF
- ASV, ASV, ASV, ASV, ASV, ASV, ASO, ASO, # E0 - E7
- ASV, ASV, ASV, ASV, ASV, ASV, ASV, ASV, # E8 - EF
- ASO, ASO, ASV, ASV, ASV, ASV, ASV, OTH, # F0 - F7
- ASV, ASV, ASV, ASV, ASV, ASO, ASO, ASO, # F8 - FF
- )
-
- # 0 : illegal
- # 1 : very unlikely
- # 2 : normal
- # 3 : very likely
- Latin1ClassModel = (
- # UDF OTH ASC ASS ACV ACO ASV ASO
- 0, 0, 0, 0, 0, 0, 0, 0, # UDF
- 0, 3, 3, 3, 3, 3, 3, 3, # OTH
- 0, 3, 3, 3, 3, 3, 3, 3, # ASC
- 0, 3, 3, 3, 1, 1, 3, 3, # ASS
- 0, 3, 3, 3, 1, 2, 1, 2, # ACV
- 0, 3, 3, 3, 3, 3, 3, 3, # ACO
- 0, 3, 1, 3, 1, 1, 1, 3, # ASV
- 0, 3, 1, 3, 1, 1, 3, 3, # ASO
- )
-
-
- class Latin1Prober(CharSetProber):
- def __init__(self):
- super(Latin1Prober, self).__init__()
- self._last_char_class = None
- self._freq_counter = None
- self.reset()
-
- def reset(self):
- self._last_char_class = OTH
- self._freq_counter = [0] * FREQ_CAT_NUM
- CharSetProber.reset(self)
-
- @property
- def charset_name(self):
- return "ISO-8859-1"
-
- @property
- def language(self):
- return ""
-
- def feed(self, byte_str):
- byte_str = self.filter_with_english_letters(byte_str)
- for c in byte_str:
- char_class = Latin1_CharToClass[c]
- freq = Latin1ClassModel[(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):
- if self.state == ProbingState.NOT_ME:
- return 0.01
-
- total = sum(self._freq_counter)
- if total < 0.01:
- confidence = 0.0
- else:
- confidence = ((self._freq_counter[3] - self._freq_counter[1] * 20.0)
- / total)
- if confidence < 0.0:
- confidence = 0.0
- # lower the confidence of latin1 so that other more accurate
- # detector can take priority.
- confidence = confidence * 0.73
- return confidence
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