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- ######################## 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 .enums import ProbingState, MachineState
- from .codingstatemachine import CodingStateMachine
- from .mbcssm import UTF8_SM_MODEL
-
-
-
- class UTF8Prober(CharSetProber):
- ONE_CHAR_PROB = 0.5
-
- def __init__(self):
- super(UTF8Prober, self).__init__()
- self.coding_sm = CodingStateMachine(UTF8_SM_MODEL)
- self._num_mb_chars = None
- self.reset()
-
- def reset(self):
- super(UTF8Prober, self).reset()
- self.coding_sm.reset()
- self._num_mb_chars = 0
-
- @property
- def charset_name(self):
- return "utf-8"
-
- @property
- def language(self):
- return ""
-
- def feed(self, byte_str):
- for c in byte_str:
- coding_state = self.coding_sm.next_state(c)
- if coding_state == MachineState.ERROR:
- self._state = ProbingState.NOT_ME
- break
- elif coding_state == MachineState.ITS_ME:
- self._state = ProbingState.FOUND_IT
- break
- elif coding_state == MachineState.START:
- if self.coding_sm.get_current_charlen() >= 2:
- self._num_mb_chars += 1
-
- if self.state == ProbingState.DETECTING:
- if self.get_confidence() > self.SHORTCUT_THRESHOLD:
- self._state = ProbingState.FOUND_IT
-
- return self.state
-
- def get_confidence(self):
- unlike = 0.99
- if self._num_mb_chars < 6:
- unlike *= self.ONE_CHAR_PROB ** self._num_mb_chars
- return 1.0 - unlike
- else:
- return unlike
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