Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/chardet/utf8prober.py: 95%

1######################## BEGIN LICENSE BLOCK ######################## 

2# The Original Code is mozilla.org code. 

3# 

4# The Initial Developer of the Original Code is 

5# Netscape Communications Corporation. 

6# Portions created by the Initial Developer are Copyright (C) 1998 

7# the Initial Developer. All Rights Reserved. 

8# 

9# Contributor(s): 

10# Mark Pilgrim - port to Python 

11# 

12# This library is free software; you can redistribute it and/or 

13# modify it under the terms of the GNU Lesser General Public 

14# License as published by the Free Software Foundation; either 

15# version 2.1 of the License, or (at your option) any later version. 

16# 

17# This library is distributed in the hope that it will be useful, 

18# but WITHOUT ANY WARRANTY; without even the implied warranty of 

19# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 

20# Lesser General Public License for more details. 

21# 

22# You should have received a copy of the GNU Lesser General Public 

23# License along with this library; if not, write to the Free Software 

24# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 

25# 02110-1301 USA 

26######################### END LICENSE BLOCK ######################### 

27 

28from typing import Union 

29 

30from .charsetprober import CharSetProber 

31from .codingstatemachine import CodingStateMachine 

32from .enums import MachineState, ProbingState 

33from .mbcssm import UTF8_SM_MODEL 

34 

35 

36class UTF8Prober(CharSetProber): 

37 ONE_CHAR_PROB = 0.5 

38 

39 def __init__(self) -> None: 

40 super().__init__() 

41 self.coding_sm = CodingStateMachine(UTF8_SM_MODEL) 

42 self._num_mb_chars = 0 

43 self.reset() 

44 

45 def reset(self) -> None: 

46 super().reset() 

47 self.coding_sm.reset() 

48 self._num_mb_chars = 0 

49 

50 @property 

51 def charset_name(self) -> str: 

52 return "utf-8" 

53 

54 @property 

55 def language(self) -> str: 

56 return "" 

57 

58 def feed(self, byte_str: Union[bytes, bytearray]) -> ProbingState: 

59 for c in byte_str: 

60 coding_state = self.coding_sm.next_state(c) 

61 if coding_state == MachineState.ERROR: 

62 self._state = ProbingState.NOT_ME 

63 break 

64 if coding_state == MachineState.ITS_ME: 

65 self._state = ProbingState.FOUND_IT 

66 break 

67 if coding_state == MachineState.START: 

68 if self.coding_sm.get_current_charlen() >= 2: 

69 self._num_mb_chars += 1 

70 

71 if self.state == ProbingState.DETECTING: 

72 if self.get_confidence() > self.SHORTCUT_THRESHOLD: 

73 self._state = ProbingState.FOUND_IT 

74 

75 return self.state 

76 

77 def get_confidence(self) -> float: 

78 unlike = 0.99 

79 if self._num_mb_chars < 6: 

80 unlike *= self.ONE_CHAR_PROB**self._num_mb_chars 

81 return 1.0 - unlike 

82 return unlike