1 | // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) |
2 | // (C) Copyright 2003-2007 Jonathan Turkanis |
3 | // Distributed under the Boost Software License, Version 1.0. (See accompanying |
4 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) |
5 | |
6 | // See http://www.boost.org/libs/iostreams for documentation. |
7 | |
8 | // |
9 | // Contains metafunctions char_type_of, category_of and mode_of used for |
10 | // deducing the i/o category and i/o mode of a model of Filter or Device. |
11 | // |
12 | // Also contains several utility metafunctions, functions and macros. |
13 | // |
14 | |
15 | #ifndef BOOST_IOSTREAMS_IO_TRAITS_HPP_INCLUDED |
16 | #define BOOST_IOSTREAMS_IO_TRAITS_HPP_INCLUDED |
17 | |
18 | #if defined(_MSC_VER) |
19 | # pragma once |
20 | #endif |
21 | |
22 | #include <iosfwd> // stream types, char_traits. |
23 | #include <boost/config.hpp> // partial spec, deduced typename. |
24 | #include <boost/detail/workaround.hpp> |
25 | #include <boost/iostreams/categories.hpp> |
26 | #include <boost/iostreams/detail/bool_trait_def.hpp> |
27 | #include <boost/iostreams/detail/config/wide_streams.hpp> |
28 | #include <boost/iostreams/detail/is_iterator_range.hpp> |
29 | #include <boost/iostreams/detail/select.hpp> |
30 | #include <boost/iostreams/detail/select_by_size.hpp> |
31 | #include <boost/iostreams/detail/wrap_unwrap.hpp> |
32 | #include <boost/iostreams/traits_fwd.hpp> |
33 | #include <boost/mpl/bool.hpp> |
34 | #include <boost/mpl/eval_if.hpp> |
35 | #include <boost/mpl/identity.hpp> |
36 | #include <boost/mpl/int.hpp> |
37 | #include <boost/mpl/or.hpp> |
38 | #include <boost/range/iterator_range.hpp> |
39 | #include <boost/range/value_type.hpp> |
40 | #include <boost/ref.hpp> |
41 | #include <boost/type_traits/is_convertible.hpp> |
42 | |
43 | // Must come last. |
44 | #include <boost/iostreams/detail/config/disable_warnings.hpp> |
45 | |
46 | namespace boost { namespace iostreams { |
47 | |
48 | //----------Definitions of predicates for streams and stream buffers----------// |
49 | |
50 | #ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //--------------------------------// |
51 | |
52 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_istream, std::basic_istream, 2) |
53 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_ostream, std::basic_ostream, 2) |
54 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_iostream, std::basic_iostream, 2) |
55 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_streambuf, std::basic_streambuf, 2) |
56 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_ifstream, std::basic_ifstream, 2) |
57 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_ofstream, std::basic_ofstream, 2) |
58 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_fstream, std::basic_fstream, 2) |
59 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_filebuf, std::basic_filebuf, 2) |
60 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_istringstream, std::basic_istringstream, 3) |
61 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_ostringstream, std::basic_ostringstream, 3) |
62 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_stringstream, std::basic_stringstream, 3) |
63 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_stringbuf, std::basic_stringbuf, 3) |
64 | |
65 | #else // #ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //-----------------------// |
66 | |
67 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_istream, std::istream, 0) |
68 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_ostream, std::ostream, 0) |
69 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_iostream, std::iostream, 0) |
70 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_streambuf, std::streambuf, 0) |
71 | |
72 | #endif // #ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //----------------------// |
73 | |
74 | template<typename T> |
75 | struct is_std_io |
76 | : mpl::or_< is_istream<T>, is_ostream<T>, is_streambuf<T> > |
77 | { }; |
78 | |
79 | template<typename T> |
80 | struct is_std_file_device |
81 | : mpl::or_< |
82 | is_ifstream<T>, |
83 | is_ofstream<T>, |
84 | is_fstream<T>, |
85 | is_filebuf<T> |
86 | > |
87 | { }; |
88 | |
89 | template<typename T> |
90 | struct is_std_string_device |
91 | : mpl::or_< |
92 | is_istringstream<T>, |
93 | is_ostringstream<T>, |
94 | is_stringstream<T>, |
95 | is_stringbuf<T> |
96 | > |
97 | { }; |
98 | |
99 | template<typename Device, typename Tr, typename Alloc> |
100 | struct stream; |
101 | |
102 | template<typename T, typename Tr, typename Alloc, typename Mode> |
103 | class stream_buffer; |
104 | |
105 | template< typename Mode, typename Ch, typename Tr, |
106 | typename Alloc, typename Access > |
107 | class filtering_stream; |
108 | |
109 | template< typename Mode, typename Ch, typename Tr, |
110 | typename Alloc, typename Access > |
111 | class wfiltering_stream; |
112 | |
113 | template< typename Mode, typename Ch, typename Tr, |
114 | typename Alloc, typename Access > |
115 | class filtering_streambuf; |
116 | |
117 | template< typename Mode, typename Ch, typename Tr, |
118 | typename Alloc, typename Access > |
119 | class filtering_wstreambuf; |
120 | |
121 | namespace detail { |
122 | |
123 | template<typename T, typename Tr> |
124 | class linked_streambuf; |
125 | |
126 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF( is_boost_stream, |
127 | boost::iostreams::stream, |
128 | 3 ) |
129 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF( is_boost_stream_buffer, |
130 | boost::iostreams::stream_buffer, |
131 | 4 ) |
132 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF( is_filtering_stream_impl, |
133 | boost::iostreams::filtering_stream, |
134 | 5 ) |
135 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF( is_filtering_wstream_impl, |
136 | boost::iostreams::wfiltering_stream, |
137 | 5 ) |
138 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF( is_filtering_streambuf_impl, |
139 | boost::iostreams::filtering_streambuf, |
140 | 5 ) |
141 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF( is_filtering_wstreambuf_impl, |
142 | boost::iostreams::filtering_wstreambuf, |
143 | 5 ) |
144 | BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_linked, linked_streambuf, 2) |
145 | |
146 | template<typename T> |
147 | struct is_filtering_stream |
148 | : mpl::or_< |
149 | is_filtering_stream_impl<T>, |
150 | is_filtering_wstream_impl<T> |
151 | > |
152 | { }; |
153 | |
154 | template<typename T> |
155 | struct is_filtering_streambuf |
156 | : mpl::or_< |
157 | is_filtering_streambuf_impl<T>, |
158 | is_filtering_wstreambuf_impl<T> |
159 | > |
160 | { }; |
161 | |
162 | template<typename T> |
163 | struct is_boost |
164 | : mpl::or_< |
165 | is_boost_stream<T>, |
166 | is_boost_stream_buffer<T>, |
167 | is_filtering_stream<T>, |
168 | is_filtering_streambuf<T> |
169 | > |
170 | { }; |
171 | |
172 | } // End namespace detail. |
173 | |
174 | //------------------Definitions of char_type_of-------------------------------// |
175 | |
176 | namespace detail { |
177 | |
178 | template<typename T> |
179 | struct member_char_type { typedef typename T::char_type type; }; |
180 | |
181 | } // End namespace detail. |
182 | |
183 | # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //-------------------------------// |
184 | |
185 | template<typename T> |
186 | struct char_type_of |
187 | : detail::member_char_type< |
188 | typename detail::unwrapped_type<T>::type |
189 | > |
190 | { }; |
191 | |
192 | # else // # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //---------------------// |
193 | |
194 | template<typename T> |
195 | struct char_type_of { |
196 | typedef typename detail::unwrapped_type<T>::type U; |
197 | typedef typename |
198 | mpl::eval_if< |
199 | is_std_io<U>, |
200 | mpl::identity<char>, |
201 | detail::member_char_type<U> |
202 | >::type type; |
203 | }; |
204 | |
205 | # endif // # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //--------------------// |
206 | |
207 | template<typename Iter> |
208 | struct char_type_of< iterator_range<Iter> > { |
209 | typedef typename iterator_value<Iter>::type type; |
210 | }; |
211 | |
212 | |
213 | //------------------Definitions of category_of--------------------------------// |
214 | |
215 | namespace detail { |
216 | |
217 | template<typename T> |
218 | struct member_category { typedef typename T::category type; }; |
219 | |
220 | } // End namespace detail. |
221 | |
222 | template<typename T> |
223 | struct category_of { |
224 | template<typename U> |
225 | struct member_category { |
226 | typedef typename U::category type; |
227 | }; |
228 | typedef typename detail::unwrapped_type<T>::type U; |
229 | typedef typename |
230 | mpl::eval_if< |
231 | mpl::and_< |
232 | is_std_io<U>, |
233 | mpl::not_< detail::is_boost<U> > |
234 | >, |
235 | iostreams::select< // Disambiguation for Tru64 |
236 | is_filebuf<U>, filebuf_tag, |
237 | is_ifstream<U>, ifstream_tag, |
238 | is_ofstream<U>, ofstream_tag, |
239 | is_fstream<U>, fstream_tag, |
240 | is_stringbuf<U>, stringbuf_tag, |
241 | is_istringstream<U>, istringstream_tag, |
242 | is_ostringstream<U>, ostringstream_tag, |
243 | is_stringstream<U>, stringstream_tag, |
244 | is_streambuf<U>, generic_streambuf_tag, |
245 | is_iostream<U>, generic_iostream_tag, |
246 | is_istream<U>, generic_istream_tag, |
247 | is_ostream<U>, generic_ostream_tag |
248 | >, |
249 | detail::member_category<U> |
250 | >::type type; |
251 | }; |
252 | |
253 | // Partial specialization for reference wrappers |
254 | |
255 | template<typename T> |
256 | struct category_of< reference_wrapper<T> > |
257 | : category_of<T> |
258 | { }; |
259 | |
260 | |
261 | //------------------Definition of get_category--------------------------------// |
262 | |
263 | // |
264 | // Returns an object of type category_of<T>::type. |
265 | // |
266 | template<typename T> |
267 | inline typename category_of<T>::type get_category(const T&) |
268 | { typedef typename category_of<T>::type category; return category(); } |
269 | |
270 | //------------------Definition of int_type_of---------------------------------// |
271 | |
272 | template<typename T> |
273 | struct int_type_of { |
274 | #ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES |
275 | typedef std::char_traits< |
276 | BOOST_DEDUCED_TYPENAME char_type_of<T>::type |
277 | > traits_type; |
278 | typedef typename traits_type::int_type type; |
279 | #else |
280 | typedef int type; |
281 | #endif |
282 | }; |
283 | |
284 | //------------------Definition of mode_of-------------------------------------// |
285 | |
286 | namespace detail { |
287 | |
288 | template<int N> struct io_mode_impl; |
289 | |
290 | #define BOOST_IOSTREAMS_MODE_HELPER(tag_, id_) \ |
291 | case_<id_> io_mode_impl_helper(tag_); \ |
292 | template<> struct io_mode_impl<id_> { typedef tag_ type; }; \ |
293 | /**/ |
294 | BOOST_IOSTREAMS_MODE_HELPER(input, 1) |
295 | BOOST_IOSTREAMS_MODE_HELPER(output, 2) |
296 | BOOST_IOSTREAMS_MODE_HELPER(bidirectional, 3) |
297 | BOOST_IOSTREAMS_MODE_HELPER(input_seekable, 4) |
298 | BOOST_IOSTREAMS_MODE_HELPER(output_seekable, 5) |
299 | BOOST_IOSTREAMS_MODE_HELPER(seekable, 6) |
300 | BOOST_IOSTREAMS_MODE_HELPER(dual_seekable, 7) |
301 | BOOST_IOSTREAMS_MODE_HELPER(bidirectional_seekable, 8) |
302 | BOOST_IOSTREAMS_MODE_HELPER(dual_use, 9) |
303 | #undef BOOST_IOSTREAMS_MODE_HELPER |
304 | |
305 | template<typename T> |
306 | struct io_mode_id { |
307 | typedef typename category_of<T>::type category; |
308 | BOOST_SELECT_BY_SIZE(int, value, detail::io_mode_impl_helper(category())); |
309 | }; |
310 | |
311 | } // End namespace detail. |
312 | |
313 | template<typename T> // Borland 5.6.4 requires this circumlocution. |
314 | struct mode_of : detail::io_mode_impl< detail::io_mode_id<T>::value > { }; |
315 | |
316 | // Partial specialization for reference wrappers |
317 | |
318 | template<typename T> |
319 | struct mode_of< reference_wrapper<T> > |
320 | : mode_of<T> |
321 | { }; |
322 | |
323 | |
324 | //------------------Definition of is_device, is_filter and is_direct----------// |
325 | |
326 | namespace detail { |
327 | |
328 | template<typename T, typename Tag> |
329 | struct has_trait_impl { |
330 | typedef typename category_of<T>::type category; |
331 | BOOST_STATIC_CONSTANT(bool, value = (is_convertible<category, Tag>::value)); |
332 | }; |
333 | |
334 | template<typename T, typename Tag> |
335 | struct has_trait |
336 | : mpl::bool_<has_trait_impl<T, Tag>::value> |
337 | { }; |
338 | |
339 | } // End namespace detail. |
340 | |
341 | template<typename T> |
342 | struct is_device : detail::has_trait<T, device_tag> { }; |
343 | |
344 | template<typename T> |
345 | struct is_filter : detail::has_trait<T, filter_tag> { }; |
346 | |
347 | template<typename T> |
348 | struct is_direct : detail::has_trait<T, direct_tag> { }; |
349 | |
350 | //------------------Definition of BOOST_IOSTREAMS_STREAMBUF_TYPEDEFS----------// |
351 | |
352 | #define BOOST_IOSTREAMS_STREAMBUF_TYPEDEFS(Tr) \ |
353 | typedef Tr traits_type; \ |
354 | typedef typename traits_type::int_type int_type; \ |
355 | typedef typename traits_type::off_type off_type; \ |
356 | typedef typename traits_type::pos_type pos_type; \ |
357 | /**/ |
358 | |
359 | } } // End namespaces iostreams, boost. |
360 | |
361 | #include <boost/iostreams/detail/config/enable_warnings.hpp> |
362 | |
363 | #endif // #ifndef BOOST_IOSTREAMS_IO_TRAITS_HPP_INCLUDED |
364 | |