moonycode/cpdetect.cpp at master · big-keva/moonycode · GitHub

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
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
# include "./codes.h"
# include <algorithm>

namespace codepages
{
  const unsigned char* GetUint( const unsigned char* src, unsigned& val )
  {
    unsigned  ushift = 0;

    for ( val = 0; ; ushift += 7 )
    {
      val |= ((*src & 0x7f) << ushift);

      if ( (*src++ & 0x80) == 0 )
        break;
    }

    return src;
  }

  template <class ... trigraph>
  unsigned  findtrig( const unsigned char*  tree, trigraph ... );

  template <class ... trigraph>
  unsigned  findtrig( const unsigned char*  tree, unsigned char next, trigraph... list )
  {
    for ( auto  size = *tree++; size-- > 0; )
    {
      auto  chtree = *tree++;

      if ( chtree <= next )
      {
        unsigned  uvalue;

        if ( chtree < next )
        {
          tree = GetUint( tree, uvalue );
          tree += uvalue;
        }
          else
        return findtrig( GetUint( tree, uvalue ), list... );
      }
        else
      break;
    }
    return 0;
  }

  template <>
  unsigned  findtrig( const unsigned char* tree )
  {
    unsigned  uvalue;

    return GetUint( tree, uvalue ), uvalue;
  }

  // detect methods

  auto  detect::codepage( const char* text, size_t size ) -> unsigned
  {
    struct  pagestat
    {
      unsigned              page;
      const unsigned char*  xlat;
      unsigned              stat = 0;
      unsigned              meet = 0;

    public:
      bool  operator < ( const pagestat& cp ) const
        {  return meet > cp.meet || (meet == cp.meet && stat > cp.stat);  }
    };

    pagestat  list[5] =
    {
      { codepage_1251, xlatOneToOne },
      { codepage_866,  xlatDosToWin },
      { codepage_iso,  xlatIsoToWin },
      { codepage_mac,  xlatMacToWin },
      { codepage_koi8, xlatKoiToWin }
    };

    unsigned  test = 0;

    if ( size == (size_t)-1 )
      for ( size = 0; text[size] != 0; ++size ) (void)NULL;

    // check for utf8
    if ( utf8::detect( text, size ) )
      return codepage_utf8;

    // build codepages stat
    for ( auto stop = text + size; text + 2 < stop; ++text )
    {
      bool  foundTrig = false;

      for ( auto& next: list )
      {
        auto  rate = findtrig( rus_trigraph,
          next.xlat[(unsigned char)text[0]],
          next.xlat[(unsigned char)text[1]],
          next.xlat[(unsigned char)text[2]]);

        if ( rate != 0 )
        {
          next.stat += rate;
          next.meet += 1;
          foundTrig = true;
        }
      }
      test += foundTrig ? 1 : 0;
    }

    // get best codepage
    std::sort( std::begin( list ), std::end( list ) );

    if ( test != 0 && list[0].meet > test / 2.0 )
      return list[0].page;

    return 0;
  }

  auto  detect::codepage( const std::string& s ) -> unsigned
  {
    return codepage( s.c_str(), s.length() );
  }

  auto  detect::trigraph( const char* trig, const unsigned char* xlat ) -> unsigned
  {
    return findtrig( rus_trigraph,
      xlat[(unsigned char)trig[0]],
      xlat[(unsigned char)trig[1]],
      xlat[(unsigned char)trig[2]] );
  }

  auto  detect::trigraph( const std::string& trig, const unsigned char* xlat ) -> unsigned
  {
    return trig.length() >= 3 ? trigraph( trig.c_str(), xlat ) : false;
  }

  auto  detect::trigraph( const widechar* trig ) -> unsigned int
  {
    return findtrig( rus_trigraph,
      (unsigned char)__impl__::utf_1251<>::translate( trig[0] ),
      (unsigned char)__impl__::utf_1251<>::translate( trig[1] ),
      (unsigned char)__impl__::utf_1251<>::translate( trig[2] ) );
  }

  bool  detect::coverage( const char* text, size_t size, const unsigned char* xlat )
  {
    if ( text == nullptr )
      return false;

    if ( size == (size_t)-1 )
      for ( size = 0; text[size] != 0; ++size ) (void)NULL;

    for ( auto stop = text + size - 2; text < stop; ++text )
      if ( !findtrig( rus_trigraph,
        xlat[(unsigned char)text[0]],
        xlat[(unsigned char)text[1]],
        xlat[(unsigned char)text[2]] ) )
      return false;

    return true;
  }

  bool  detect::coverage( const std::string& text, const unsigned char* xlat )
  {
    return coverage( text.c_str(), text.length(), xlat );
  }

  bool  detect::coverage( const widechar* text, size_t size )
  {
    if ( text == nullptr )
      return false;

    if ( size == (size_t)-1 )
      for ( size = 0; text[size] != 0; ++size ) (void)NULL;

    for ( auto stop = text + size - 2; text < stop; ++text )
      if ( !findtrig( rus_trigraph,
        (unsigned char)__impl__::utf_1251<>::translate( text[0] ),
        (unsigned char)__impl__::utf_1251<>::translate( text[1] ),
        (unsigned char)__impl__::utf_1251<>::translate( text[2] ) ) )
      return false;

    return true;
  }

}