Current File : //lib/python3/dist-packages/chardet/escprober.py
######################## 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 typing import Optional, Union
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,
)
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: LanguageFilter = LanguageFilter.NONE) -> 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 = 0
self._detected_charset: Optional[str] = None
self._detected_language: Optional[str] = None
self._state = ProbingState.DETECTING
self.reset()
def reset(self) -> None:
super().reset()
for coding_sm in self.coding_sm:
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) -> Optional[str]:
return self._detected_charset
@property
def language(self) -> Optional[str]:
return self._detected_language
def get_confidence(self) -> float:
return 0.99 if self._detected_charset else 0.00
def feed(self, byte_str: Union[bytes, bytearray]) -> ProbingState:
for c in byte_str:
for coding_sm in self.coding_sm:
if 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
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