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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 |