171 lines
6.7 KiB
Python
171 lines
6.7 KiB
Python
######################## BEGIN LICENSE BLOCK ########################
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# The Original Code is Mozilla Universal charset detector code.
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#
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# The Initial Developer of the Original Code is
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# Netscape Communications Corporation.
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# Portions created by the Initial Developer are Copyright (C) 2001
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# the Initial Developer. All Rights Reserved.
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#
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# Contributor(s):
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# Mark Pilgrim - port to Python
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# Shy Shalom - original C code
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#
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# This library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this library; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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# 02110-1301 USA
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######################### END LICENSE BLOCK #########################
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from . import constants
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import sys
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import codecs
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from .latin1prober import Latin1Prober # windows-1252
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from .mbcsgroupprober import MBCSGroupProber # multi-byte character sets
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from .sbcsgroupprober import SBCSGroupProber # single-byte character sets
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from .escprober import EscCharSetProber # ISO-2122, etc.
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import re
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MINIMUM_THRESHOLD = 0.20
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ePureAscii = 0
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eEscAscii = 1
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eHighbyte = 2
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class UniversalDetector:
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def __init__(self):
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self._highBitDetector = re.compile(b'[\x80-\xFF]')
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self._escDetector = re.compile(b'(\033|~{)')
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self._mEscCharSetProber = None
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self._mCharSetProbers = []
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self.reset()
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def reset(self):
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self.result = {'encoding': None, 'confidence': 0.0}
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self.done = False
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self._mStart = True
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self._mGotData = False
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self._mInputState = ePureAscii
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self._mLastChar = b''
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if self._mEscCharSetProber:
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self._mEscCharSetProber.reset()
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for prober in self._mCharSetProbers:
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prober.reset()
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def feed(self, aBuf):
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if self.done:
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return
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aLen = len(aBuf)
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if not aLen:
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return
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if not self._mGotData:
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# If the data starts with BOM, we know it is UTF
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if aBuf[:3] == codecs.BOM_UTF8:
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# EF BB BF UTF-8 with BOM
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self.result = {'encoding': "UTF-8-SIG", 'confidence': 1.0}
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elif aBuf[:4] == codecs.BOM_UTF32_LE:
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# FF FE 00 00 UTF-32, little-endian BOM
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self.result = {'encoding': "UTF-32LE", 'confidence': 1.0}
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elif aBuf[:4] == codecs.BOM_UTF32_BE:
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# 00 00 FE FF UTF-32, big-endian BOM
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self.result = {'encoding': "UTF-32BE", 'confidence': 1.0}
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elif aBuf[:4] == b'\xFE\xFF\x00\x00':
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# FE FF 00 00 UCS-4, unusual octet order BOM (3412)
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self.result = {
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'encoding': "X-ISO-10646-UCS-4-3412",
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'confidence': 1.0
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}
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elif aBuf[:4] == b'\x00\x00\xFF\xFE':
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# 00 00 FF FE UCS-4, unusual octet order BOM (2143)
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self.result = {
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'encoding': "X-ISO-10646-UCS-4-2143",
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'confidence': 1.0
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}
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elif aBuf[:2] == codecs.BOM_LE:
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# FF FE UTF-16, little endian BOM
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self.result = {'encoding': "UTF-16LE", 'confidence': 1.0}
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elif aBuf[:2] == codecs.BOM_BE:
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# FE FF UTF-16, big endian BOM
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self.result = {'encoding': "UTF-16BE", 'confidence': 1.0}
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self._mGotData = True
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if self.result['encoding'] and (self.result['confidence'] > 0.0):
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self.done = True
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return
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if self._mInputState == ePureAscii:
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if self._highBitDetector.search(aBuf):
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self._mInputState = eHighbyte
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elif ((self._mInputState == ePureAscii) and
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self._escDetector.search(self._mLastChar + aBuf)):
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self._mInputState = eEscAscii
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self._mLastChar = aBuf[-1:]
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if self._mInputState == eEscAscii:
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if not self._mEscCharSetProber:
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self._mEscCharSetProber = EscCharSetProber()
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if self._mEscCharSetProber.feed(aBuf) == constants.eFoundIt:
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self.result = {'encoding': self._mEscCharSetProber.get_charset_name(),
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'confidence': self._mEscCharSetProber.get_confidence()}
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self.done = True
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elif self._mInputState == eHighbyte:
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if not self._mCharSetProbers:
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self._mCharSetProbers = [MBCSGroupProber(), SBCSGroupProber(),
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Latin1Prober()]
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for prober in self._mCharSetProbers:
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if prober.feed(aBuf) == constants.eFoundIt:
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self.result = {'encoding': prober.get_charset_name(),
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'confidence': prober.get_confidence()}
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self.done = True
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break
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def close(self):
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if self.done:
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return
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if not self._mGotData:
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if constants._debug:
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sys.stderr.write('no data received!\n')
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return
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self.done = True
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if self._mInputState == ePureAscii:
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self.result = {'encoding': 'ascii', 'confidence': 1.0}
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return self.result
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if self._mInputState == eHighbyte:
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proberConfidence = None
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maxProberConfidence = 0.0
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maxProber = None
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for prober in self._mCharSetProbers:
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if not prober:
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continue
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proberConfidence = prober.get_confidence()
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if proberConfidence > maxProberConfidence:
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maxProberConfidence = proberConfidence
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maxProber = prober
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if maxProber and (maxProberConfidence > MINIMUM_THRESHOLD):
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self.result = {'encoding': maxProber.get_charset_name(),
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'confidence': maxProber.get_confidence()}
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return self.result
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if constants._debug:
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sys.stderr.write('no probers hit minimum threshhold\n')
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for prober in self._mCharSetProbers[0].mProbers:
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if not prober:
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continue
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sys.stderr.write('%s confidence = %s\n' %
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(prober.get_charset_name(),
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prober.get_confidence()))
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