1 /*
2 *
3 * Copyright (c) 1998-2002
4 * John Maddock
5 *
6 * Use, modification and distribution are subject to the
7 * Boost Software License, Version 1.0. (See accompanying file
8 * LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
9 *
10 */
11
12 /*
13 * LOCATION: see http://www.boost.org for most recent version.
14 * FILE: primary_transform.hpp
15 * VERSION: see <boost/version.hpp>
16 * DESCRIPTION: Heuristically determines the sort string format in use
17 * by the current locale.
18 */
19
20 #ifndef BOOST_REGEX_PRIMARY_TRANSFORM
21 #define BOOST_REGEX_PRIMARY_TRANSFORM
22
23 #ifdef BOOST_MSVC
24 #pragma warning(push)
25 #pragma warning(disable: 4103)
26 #endif
27 #ifdef BOOST_HAS_ABI_HEADERS
28 # include BOOST_ABI_PREFIX
29 #endif
30 #ifdef BOOST_MSVC
31 #pragma warning(pop)
32 #endif
33
34 namespace boost{
35 namespace re_detail{
36
37
38 enum{
39 sort_C,
40 sort_fixed,
41 sort_delim,
42 sort_unknown
43 };
44
45 template <class S, class charT>
count_chars(const S & s,charT c)46 unsigned count_chars(const S& s, charT c)
47 {
48 //
49 // Count how many occurances of character c occur
50 // in string s: if c is a delimeter between collation
51 // fields, then this should be the same value for all
52 // sort keys:
53 //
54 unsigned int count = 0;
55 for(unsigned pos = 0; pos < s.size(); ++pos)
56 {
57 if(s[pos] == c) ++count;
58 }
59 return count;
60 }
61
62
63 template <class traits, class charT>
find_sort_syntax(const traits * pt,charT * delim)64 unsigned find_sort_syntax(const traits* pt, charT* delim)
65 {
66 //
67 // compare 'a' with 'A' to see how similar they are,
68 // should really use a-accute but we can't portably do that,
69 //
70 typedef typename traits::string_type string_type;
71 typedef typename traits::char_type char_type;
72
73 // Suppress incorrect warning for MSVC
74 (void)pt;
75
76 char_type a[2] = {'a', '\0', };
77 string_type sa(pt->transform(a, a+1));
78 if(sa == a)
79 {
80 *delim = 0;
81 return sort_C;
82 }
83 char_type A[2] = { 'A', '\0', };
84 string_type sA(pt->transform(A, A+1));
85 char_type c[2] = { ';', '\0', };
86 string_type sc(pt->transform(c, c+1));
87
88 int pos = 0;
89 while((pos <= static_cast<int>(sa.size())) && (pos <= static_cast<int>(sA.size())) && (sa[pos] == sA[pos])) ++pos;
90 --pos;
91 if(pos < 0)
92 {
93 *delim = 0;
94 return sort_unknown;
95 }
96 //
97 // at this point sa[pos] is either the end of a fixed width field
98 // or the character that acts as a delimiter:
99 //
100 charT maybe_delim = sa[pos];
101 if((pos != 0) && (count_chars(sa, maybe_delim) == count_chars(sA, maybe_delim)) && (count_chars(sa, maybe_delim) == count_chars(sc, maybe_delim)))
102 {
103 *delim = maybe_delim;
104 return sort_delim;
105 }
106 //
107 // OK doen't look like a delimiter, try for fixed width field:
108 //
109 if((sa.size() == sA.size()) && (sa.size() == sc.size()))
110 {
111 // note assumes that the fixed width field is less than
112 // (numeric_limits<charT>::max)(), should be true for all types
113 // I can't imagine 127 character fields...
114 *delim = static_cast<charT>(++pos);
115 return sort_fixed;
116 }
117 //
118 // don't know what it is:
119 //
120 *delim = 0;
121 return sort_unknown;
122 }
123
124
125 } // namespace re_detail
126 } // namespace boost
127
128 #ifdef BOOST_MSVC
129 #pragma warning(push)
130 #pragma warning(disable: 4103)
131 #endif
132 #ifdef BOOST_HAS_ABI_HEADERS
133 # include BOOST_ABI_SUFFIX
134 #endif
135 #ifdef BOOST_MSVC
136 #pragma warning(pop)
137 #endif
138
139 #endif
140
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