cd0e9e7078b38741e9e610d7b9a92a78369a3eb9
[sdc/sdc-distribution-client.git] /
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
28 import sys
29 from .mbcharsetprober import MultiByteCharSetProber
30 from .codingstatemachine import CodingStateMachine
31 from .chardistribution import SJISDistributionAnalysis
32 from .jpcntx import SJISContextAnalysis
33 from .mbcssm import SJISSMModel
34 from . import constants
35
36
37 class SJISProber(MultiByteCharSetProber):
38     def __init__(self):
39         MultiByteCharSetProber.__init__(self)
40         self._mCodingSM = CodingStateMachine(SJISSMModel)
41         self._mDistributionAnalyzer = SJISDistributionAnalysis()
42         self._mContextAnalyzer = SJISContextAnalysis()
43         self.reset()
44
45     def reset(self):
46         MultiByteCharSetProber.reset(self)
47         self._mContextAnalyzer.reset()
48
49     def get_charset_name(self):
50         return self._mContextAnalyzer.get_charset_name()
51
52     def feed(self, aBuf):
53         aLen = len(aBuf)
54         for i in range(0, aLen):
55             codingState = self._mCodingSM.next_state(aBuf[i])
56             if codingState == constants.eError:
57                 if constants._debug:
58                     sys.stderr.write(self.get_charset_name()
59                                      + ' prober hit error at byte ' + str(i)
60                                      + '\n')
61                 self._mState = constants.eNotMe
62                 break
63             elif codingState == constants.eItsMe:
64                 self._mState = constants.eFoundIt
65                 break
66             elif codingState == constants.eStart:
67                 charLen = self._mCodingSM.get_current_charlen()
68                 if i == 0:
69                     self._mLastChar[1] = aBuf[0]
70                     self._mContextAnalyzer.feed(self._mLastChar[2 - charLen:],
71                                                 charLen)
72                     self._mDistributionAnalyzer.feed(self._mLastChar, charLen)
73                 else:
74                     self._mContextAnalyzer.feed(aBuf[i + 1 - charLen:i + 3
75                                                      - charLen], charLen)
76                     self._mDistributionAnalyzer.feed(aBuf[i - 1:i + 1],
77                                                      charLen)
78
79         self._mLastChar[0] = aBuf[aLen - 1]
80
81         if self.get_state() == constants.eDetecting:
82             if (self._mContextAnalyzer.got_enough_data() and
83                (self.get_confidence() > constants.SHORTCUT_THRESHOLD)):
84                 self._mState = constants.eFoundIt
85
86         return self.get_state()
87
88     def get_confidence(self):
89         contxtCf = self._mContextAnalyzer.get_confidence()
90         distribCf = self._mDistributionAnalyzer.get_confidence()
91         return max(contxtCf, distribCf)