96 lines
3.6 KiB
Python
96 lines
3.6 KiB
Python
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######################## 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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# Proofpoint, Inc.
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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 typing import Optional, Union
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from .chardistribution import CharDistributionAnalysis
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from .charsetprober import CharSetProber
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from .codingstatemachine import CodingStateMachine
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from .enums import LanguageFilter, MachineState, ProbingState
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class MultiByteCharSetProber(CharSetProber):
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"""
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MultiByteCharSetProber
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"""
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def __init__(self, lang_filter: LanguageFilter = LanguageFilter.NONE) -> None:
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super().__init__(lang_filter=lang_filter)
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self.distribution_analyzer: Optional[CharDistributionAnalysis] = None
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self.coding_sm: Optional[CodingStateMachine] = None
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self._last_char = bytearray(b"\0\0")
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def reset(self) -> None:
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super().reset()
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if self.coding_sm:
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self.coding_sm.reset()
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if self.distribution_analyzer:
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self.distribution_analyzer.reset()
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self._last_char = bytearray(b"\0\0")
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def feed(self, byte_str: Union[bytes, bytearray]) -> ProbingState:
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assert self.coding_sm is not None
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assert self.distribution_analyzer is not None
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for i, byte in enumerate(byte_str):
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coding_state = self.coding_sm.next_state(byte)
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if coding_state == MachineState.ERROR:
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self.logger.debug(
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"%s %s prober hit error at byte %s",
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self.charset_name,
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self.language,
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i,
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)
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self._state = ProbingState.NOT_ME
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break
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if coding_state == MachineState.ITS_ME:
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self._state = ProbingState.FOUND_IT
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break
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if coding_state == MachineState.START:
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char_len = self.coding_sm.get_current_charlen()
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if i == 0:
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self._last_char[1] = byte
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self.distribution_analyzer.feed(self._last_char, char_len)
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else:
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self.distribution_analyzer.feed(byte_str[i - 1 : i + 1], char_len)
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self._last_char[0] = byte_str[-1]
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if self.state == ProbingState.DETECTING:
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if self.distribution_analyzer.got_enough_data() and (
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self.get_confidence() > self.SHORTCUT_THRESHOLD
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):
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self._state = ProbingState.FOUND_IT
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return self.state
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def get_confidence(self) -> float:
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assert self.distribution_analyzer is not None
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return self.distribution_analyzer.get_confidence()
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