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1 | // |
2 | // Copyright (c) 2009-2011 Artyom Beilis (Tonkikh) | |
3 | // | |
4 | // Distributed under the Boost Software License, Version 1.0. (See | |
5 | // accompanying file LICENSE_1_0.txt or copy at | |
6 | // http://www.boost.org/LICENSE_1_0.txt) | |
7 | // | |
8 | #ifndef BOOST_LOCALE_COLLATOR_HPP_INCLUDED | |
9 | #define BOOST_LOCALE_COLLATOR_HPP_INCLUDED | |
10 | ||
11 | #include <boost/locale/config.hpp> | |
12 | #ifdef BOOST_MSVC | |
13 | # pragma warning(push) | |
14 | # pragma warning(disable : 4275 4251 4231 4660) | |
15 | #endif | |
16 | #include <locale> | |
17 | ||
18 | ||
19 | namespace boost { | |
20 | namespace locale { | |
21 | ||
22 | class info; | |
23 | ||
24 | /// | |
25 | /// \defgroup collation Collation | |
26 | /// | |
27 | /// This module introduces collation related classes | |
28 | /// | |
29 | /// @{ | |
30 | ||
31 | /// | |
32 | /// \brief a base class that includes collation level flags | |
33 | /// | |
34 | ||
35 | class collator_base { | |
36 | public: | |
37 | /// | |
38 | /// Unicode collation level types | |
39 | /// | |
40 | typedef enum { | |
41 | primary = 0, ///< 1st collation level: base letters | |
42 | secondary = 1, ///< 2nd collation level: letters and accents | |
43 | tertiary = 2, ///< 3rd collation level: letters, accents and case | |
44 | quaternary = 3, ///< 4th collation level: letters, accents, case and punctuation | |
45 | identical = 4 ///< identical collation level: include code-point comparison | |
46 | } level_type; | |
47 | }; | |
48 | ||
49 | /// | |
50 | /// \brief Collation facet. | |
51 | /// | |
52 | /// It reimplements standard C++ std::collate, | |
53 | /// allowing usage of std::locale for direct string comparison | |
54 | /// | |
55 | template<typename CharType> | |
56 | class collator : | |
57 | public std::collate<CharType>, | |
58 | public collator_base | |
59 | { | |
60 | public: | |
61 | /// | |
62 | /// Type of the underlying character | |
63 | /// | |
64 | typedef CharType char_type; | |
65 | /// | |
66 | /// Type of string used with this facet | |
67 | /// | |
68 | typedef std::basic_string<CharType> string_type; | |
69 | ||
70 | ||
71 | /// | |
72 | /// Compare two strings in rage [b1,e1), [b2,e2) according using a collation level \a level. Calls do_compare | |
73 | /// | |
74 | /// Returns -1 if the first of the two strings sorts before the seconds, returns 1 if sorts after and 0 if | |
75 | /// they considered equal. | |
76 | /// | |
77 | int compare(level_type level, | |
78 | char_type const *b1,char_type const *e1, | |
79 | char_type const *b2,char_type const *e2) const | |
80 | { | |
81 | return do_compare(level,b1,e1,b2,e2); | |
82 | } | |
83 | /// | |
84 | /// Create a binary string that can be compared to other in order to get collation order. The string is created | |
85 | /// for text in range [b,e). It is useful for collation of multiple strings for text. | |
86 | /// | |
87 | /// The transformation follows these rules: | |
88 | /// \code | |
89 | /// compare(level,b1,e1,b2,e2) == sign( transform(level,b1,e1).compare(transform(level,b2,e2)) ); | |
90 | /// \endcode | |
91 | /// | |
92 | /// Calls do_transform | |
93 | /// | |
94 | string_type transform(level_type level,char_type const *b,char_type const *e) const | |
95 | { | |
96 | return do_transform(level,b,e); | |
97 | } | |
98 | ||
99 | /// | |
100 | /// Calculate a hash of a text in range [b,e). The value can be used for collation sensitive string comparison. | |
101 | /// | |
102 | /// If compare(level,b1,e1,b2,e2) == 0 then hash(level,b1,e1) == hash(level,b2,e2) | |
103 | /// | |
104 | /// Calls do_hash | |
105 | /// | |
106 | long hash(level_type level,char_type const *b,char_type const *e) const | |
107 | { | |
108 | return do_hash(level,b,e); | |
109 | } | |
110 | ||
111 | /// | |
112 | /// Compare two strings \a l and \a r using collation level \a level | |
113 | /// | |
114 | /// Returns -1 if the first of the two strings sorts before the seconds, returns 1 if sorts after and 0 if | |
115 | /// they considered equal. | |
116 | /// | |
117 | /// | |
118 | int compare(level_type level,string_type const &l,string_type const &r) const | |
119 | { | |
120 | return do_compare(level,l.data(),l.data()+l.size(),r.data(),r.data()+r.size()); | |
121 | } | |
122 | ||
123 | /// | |
124 | /// Calculate a hash that can be used for collation sensitive string comparison of a string \a s | |
125 | /// | |
126 | /// If compare(level,s1,s2) == 0 then hash(level,s1) == hash(level,s2) | |
127 | /// | |
128 | ||
129 | long hash(level_type level,string_type const &s) const | |
130 | { | |
131 | return do_hash(level,s.data(),s.data()+s.size()); | |
132 | } | |
133 | /// | |
134 | /// Create a binary string from string \a s, that can be compared to other, useful for collation of multiple | |
135 | /// strings. | |
136 | /// | |
137 | /// The transformation follows these rules: | |
138 | /// \code | |
139 | /// compare(level,s1,s2) == sign( transform(level,s1).compare(transform(level,s2)) ); | |
140 | /// \endcode | |
141 | /// | |
142 | string_type transform(level_type level,string_type const &s) const | |
143 | { | |
144 | return do_transform(level,s.data(),s.data()+s.size()); | |
145 | } | |
146 | ||
147 | protected: | |
148 | ||
149 | /// | |
150 | /// constructor of the collator object | |
151 | /// | |
152 | collator(size_t refs = 0) : std::collate<CharType>(refs) | |
153 | { | |
154 | } | |
155 | ||
156 | virtual ~collator() | |
157 | { | |
158 | } | |
159 | ||
160 | /// | |
161 | /// This function is used to override default collation function that does not take in account collation level. | |
162 | /// Uses primary level | |
163 | /// | |
164 | virtual int do_compare( char_type const *b1,char_type const *e1, | |
165 | char_type const *b2,char_type const *e2) const | |
166 | { | |
167 | return do_compare(identical,b1,e1,b2,e2); | |
168 | } | |
169 | /// | |
170 | /// This function is used to override default collation function that does not take in account collation level. | |
171 | /// Uses primary level | |
172 | /// | |
173 | virtual string_type do_transform(char_type const *b,char_type const *e) const | |
174 | { | |
175 | return do_transform(identical,b,e); | |
176 | } | |
177 | /// | |
178 | /// This function is used to override default collation function that does not take in account collation level. | |
179 | /// Uses primary level | |
180 | /// | |
181 | virtual long do_hash(char_type const *b,char_type const *e) const | |
182 | { | |
183 | return do_hash(identical,b,e); | |
184 | } | |
185 | ||
186 | /// | |
187 | /// Actual function that performs comparison between the strings. For details see compare member function. Can be overridden. | |
188 | /// | |
189 | virtual int do_compare( level_type level, | |
190 | char_type const *b1,char_type const *e1, | |
191 | char_type const *b2,char_type const *e2) const = 0; | |
192 | /// | |
193 | /// Actual function that performs transformation. For details see transform member function. Can be overridden. | |
194 | /// | |
195 | virtual string_type do_transform(level_type level,char_type const *b,char_type const *e) const = 0; | |
196 | /// | |
197 | /// Actual function that calculates hash. For details see hash member function. Can be overridden. | |
198 | /// | |
199 | virtual long do_hash(level_type level,char_type const *b,char_type const *e) const = 0; | |
200 | ||
201 | ||
202 | }; | |
203 | ||
204 | /// | |
205 | /// \brief This class can be used in STL algorithms and containers for comparison of strings | |
206 | /// with a level other than primary | |
207 | /// | |
208 | /// For example: | |
209 | /// | |
210 | /// \code | |
211 | /// std::map<std::string,std::string,comparator<char,collator_base::secondary> > data; | |
212 | /// \endcode | |
213 | /// | |
214 | /// Would create a map the keys of which are sorted using secondary collation level | |
215 | /// | |
216 | template<typename CharType,collator_base::level_type default_level = collator_base::identical> | |
217 | struct comparator | |
218 | { | |
219 | public: | |
220 | /// | |
221 | /// Create a comparator class for locale \a l and with collation leval \a level | |
222 | /// | |
223 | /// \note throws std::bad_cast if l does not have \ref collator facet installed | |
224 | /// | |
225 | comparator(std::locale const &l=std::locale(),collator_base::level_type level=default_level) : | |
226 | locale_(l), | |
227 | level_(level) | |
228 | { | |
229 | } | |
230 | ||
231 | /// | |
232 | /// Compare two strings -- equivalent to return left < right according to collation rules | |
233 | /// | |
234 | bool operator()(std::basic_string<CharType> const &left,std::basic_string<CharType> const &right) const | |
235 | { | |
236 | return std::use_facet<collator<CharType> >(locale_).compare(level_,left,right) < 0; | |
237 | } | |
238 | private: | |
239 | std::locale locale_; | |
240 | collator_base::level_type level_; | |
241 | }; | |
242 | ||
243 | ||
244 | /// | |
245 | ///@} | |
246 | /// | |
247 | ||
248 | } // locale | |
249 | } // boost | |
250 | ||
251 | #ifdef BOOST_MSVC | |
252 | #pragma warning(pop) | |
253 | #endif | |
254 | ||
255 | ||
256 | #endif | |
257 | /// | |
258 | /// \example collate.cpp | |
259 | /// Example of using collation functions | |
260 | /// | |
261 | // vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4 |