Source code for chardet.escprober

######################## BEGIN LICENSE BLOCK ########################
# The Original Code is mozilla.org code.
#
# The Initial Developer of the Original Code is
# Netscape Communications Corporation.
# Portions created by the Initial Developer are Copyright (C) 1998
# the Initial Developer. All Rights Reserved.
#
# Contributor(s):
#   Mark Pilgrim - port to Python
#
# 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 .codingstatemachine import CodingStateMachine
from .enums import LanguageFilter, MachineState, ProbingState
from .escsm import (
    HZ_SM_MODEL,
    ISO2022CN_SM_MODEL,
    ISO2022JP_SM_MODEL,
    ISO2022KR_SM_MODEL,
)


[docs]class EscCharSetProber(CharSetProber): """ This CharSetProber uses a "code scheme" approach for detecting encodings, whereby easily recognizable escape or shift sequences are relied on to identify these encodings. """ def __init__(self, lang_filter=None): super().__init__(lang_filter=lang_filter) self.coding_sm = [] if self.lang_filter & LanguageFilter.CHINESE_SIMPLIFIED: self.coding_sm.append(CodingStateMachine(HZ_SM_MODEL)) self.coding_sm.append(CodingStateMachine(ISO2022CN_SM_MODEL)) if self.lang_filter & LanguageFilter.JAPANESE: self.coding_sm.append(CodingStateMachine(ISO2022JP_SM_MODEL)) if self.lang_filter & LanguageFilter.KOREAN: self.coding_sm.append(CodingStateMachine(ISO2022KR_SM_MODEL)) self.active_sm_count = None self._detected_charset = None self._detected_language = None self._state = None self.reset()
[docs] def reset(self): super().reset() for coding_sm in self.coding_sm: if not coding_sm: continue coding_sm.active = True coding_sm.reset() self.active_sm_count = len(self.coding_sm) self._detected_charset = None self._detected_language = None
@property def charset_name(self): return self._detected_charset @property def language(self): return self._detected_language
[docs] def get_confidence(self): if self._detected_charset: return 0.99 else: return 0.00
[docs] def feed(self, byte_str): for c in byte_str: for coding_sm in self.coding_sm: if not coding_sm or not coding_sm.active: continue coding_state = coding_sm.next_state(c) if coding_state == MachineState.ERROR: coding_sm.active = False self.active_sm_count -= 1 if self.active_sm_count <= 0: self._state = ProbingState.NOT_ME return self.state elif coding_state == MachineState.ITS_ME: self._state = ProbingState.FOUND_IT self._detected_charset = coding_sm.get_coding_state_machine() self._detected_language = coding_sm.language return self.state return self.state