summaryrefslogtreecommitdiff
path: root/requests-0.14.0/build/lib.linux-x86_64-2.6/requests/packages/chardet/latin1prober.py
blob: b46129ba8292c2b2baa7611ccdd5b0f7615cb195 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
######################## BEGIN LICENSE BLOCK ########################
# The Original Code is Mozilla Universal charset detector code.
#
# The Initial Developer of the Original Code is
# Netscape Communications Corporation.
# Portions created by the Initial Developer are Copyright (C) 2001
# the Initial Developer. All Rights Reserved.
#
# Contributor(s):
#   Mark Pilgrim - port to Python
#   Shy Shalom - original C code
#
# 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
import constants
import operator

FREQ_CAT_NUM = 4

UDF = 0 # undefined
OTH = 1 # other
ASC = 2 # ascii capital letter
ASS = 3 # ascii small letter
ACV = 4 # accent capital vowel
ACO = 5 # accent capital other
ASV = 6 # accent small vowel
ASO = 7 # accent small other
CLASS_NUM = 8 # total classes

Latin1_CharToClass = ( \
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # 00 - 07
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # 08 - 0F
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # 10 - 17
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # 18 - 1F
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # 20 - 27
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # 28 - 2F
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # 30 - 37
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # 38 - 3F
  OTH, ASC, ASC, ASC, ASC, ASC, ASC, ASC,   # 40 - 47
  ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,   # 48 - 4F
  ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,   # 50 - 57
  ASC, ASC, ASC, OTH, OTH, OTH, OTH, OTH,   # 58 - 5F
  OTH, ASS, ASS, ASS, ASS, ASS, ASS, ASS,   # 60 - 67
  ASS, ASS, ASS, ASS, ASS, ASS, ASS, ASS,   # 68 - 6F
  ASS, ASS, ASS, ASS, ASS, ASS, ASS, ASS,   # 70 - 77
  ASS, ASS, ASS, OTH, OTH, OTH, OTH, OTH,   # 78 - 7F
  OTH, UDF, OTH, ASO, OTH, OTH, OTH, OTH,   # 80 - 87
  OTH, OTH, ACO, OTH, ACO, UDF, ACO, UDF,   # 88 - 8F
  UDF, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # 90 - 97
  OTH, OTH, ASO, OTH, ASO, UDF, ASO, ACO,   # 98 - 9F
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # A0 - A7
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # A8 - AF
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # B0 - B7
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   # B8 - BF
  ACV, ACV, ACV, ACV, ACV, ACV, ACO, ACO,   # C0 - C7
  ACV, ACV, ACV, ACV, ACV, ACV, ACV, ACV,   # C8 - CF
  ACO, ACO, ACV, ACV, ACV, ACV, ACV, OTH,   # D0 - D7
  ACV, ACV, ACV, ACV, ACV, ACO, ACO, ACO,   # D8 - DF
  ASV, ASV, ASV, ASV, ASV, ASV, ASO, ASO,   # E0 - E7
  ASV, ASV, ASV, ASV, ASV, ASV, ASV, ASV,   # E8 - EF
  ASO, ASO, ASV, ASV, ASV, ASV, ASV, OTH,   # F0 - F7
  ASV, ASV, ASV, ASV, ASV, ASO, ASO, ASO,   # F8 - FF
)

# 0 : illegal 
# 1 : very unlikely 
# 2 : normal 
# 3 : very likely
Latin1ClassModel = ( \
# UDF OTH ASC ASS ACV ACO ASV ASO
   0,  0,  0,  0,  0,  0,  0,  0,  # UDF
   0,  3,  3,  3,  3,  3,  3,  3,  # OTH
   0,  3,  3,  3,  3,  3,  3,  3,  # ASC
   0,  3,  3,  3,  1,  1,  3,  3,  # ASS
   0,  3,  3,  3,  1,  2,  1,  2,  # ACV
   0,  3,  3,  3,  3,  3,  3,  3,  # ACO
   0,  3,  1,  3,  1,  1,  1,  3,  # ASV
   0,  3,  1,  3,  1,  1,  3,  3,  # ASO
)

class Latin1Prober(CharSetProber):
    def __init__(self):
        CharSetProber.__init__(self)
        self.reset()

    def reset(self):
        self._mLastCharClass = OTH
        self._mFreqCounter = [0] * FREQ_CAT_NUM
        CharSetProber.reset(self)

    def get_charset_name(self):
        return "windows-1252"

    def feed(self, aBuf):
        aBuf = self.filter_with_english_letters(aBuf)
        for c in aBuf:
            charClass = Latin1_CharToClass[ord(c)]
            freq = Latin1ClassModel[(self._mLastCharClass * CLASS_NUM) + charClass]
            if freq == 0:
                self._mState = constants.eNotMe
                break
            self._mFreqCounter[freq] += 1
            self._mLastCharClass = charClass

        return self.get_state()

    def get_confidence(self):
        if self.get_state() == constants.eNotMe:
            return 0.01
  
        total = reduce(operator.add, self._mFreqCounter)
        if total < 0.01:
            confidence = 0.0
        else:
            confidence = (self._mFreqCounter[3] / total) - (self._mFreqCounter[1] * 20.0 / total)
        if confidence < 0.0:
            confidence = 0.0
        # lower the confidence of latin1 so that other more accurate detector 
        # can take priority.
        confidence = confidence * 0.5
        return confidence