| ######################## 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 MachineState, ProbingState |
| from .mbcssm import UTF8_SM_MODEL |
| |
| |
| class UTF8Prober(CharSetProber): |
| ONE_CHAR_PROB = 0.5 |
| |
| def __init__(self): |
| super().__init__() |
| self.coding_sm = CodingStateMachine(UTF8_SM_MODEL) |
| self._num_mb_chars = None |
| self.reset() |
| |
| def reset(self): |
| super().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 |
| if coding_state == MachineState.ITS_ME: |
| self._state = ProbingState.FOUND_IT |
| break |
| if 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 |
| return unlike |
