1 // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
2 // (C) Copyright 2005-2007 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 // Note: bidirectional streams are not supported.
9
10 #ifndef BOOST_IOSTREAMS_COMPOSE_HPP_INCLUDED
11 #define BOOST_IOSTREAMS_COMPOSE_HPP_INCLUDED
12
13 #if defined(_MSC_VER)
14 # pragma once
15 #endif
16
17 #include <algorithm> // min.
18 #include <utility> // pair.
19 #include <boost/config.hpp> // DEDUCED_TYPENAME.
20 #include <boost/iostreams/categories.hpp>
21 #include <boost/iostreams/detail/adapter/direct_adapter.hpp>
22 #include <boost/iostreams/detail/call_traits.hpp>
23 #include <boost/iostreams/detail/enable_if_stream.hpp>
24 #include <boost/iostreams/detail/execute.hpp>
25 #include <boost/iostreams/detail/functional.hpp>
26 #include <boost/iostreams/operations.hpp>
27 #include <boost/iostreams/traits.hpp> // mode_of, is_direct.
28 #include <boost/mpl/if.hpp>
29 #include <boost/ref.hpp>
30 #include <boost/static_assert.hpp>
31 #include <boost/type_traits/is_convertible.hpp>
32
33 // Must come last.
34 #include <boost/iostreams/detail/config/disable_warnings.hpp> // MSVC.
35
36 namespace boost { namespace iostreams {
37
38 namespace detail {
39
40 template< typename First,
41 typename Second,
42 typename FirstMode =
43 BOOST_DEDUCED_TYPENAME mode_of<First>::type,
44 typename SecondMode =
45 BOOST_DEDUCED_TYPENAME mode_of<Second>::type >
46 struct composite_mode
47 : select<
48 is_convertible<SecondMode, FirstMode>, FirstMode,
49 is_convertible<FirstMode, SecondMode>, SecondMode,
50 is_convertible<SecondMode, input>, input,
51 else_, output
52 >
53 { };
54
55 //
56 // Template name: composite_device.
57 // Description: Provides a Device view of a Filter, Device pair.
58 // Template parameters:
59 // Filter - A model of Filter.
60 // Device - An indirect model of Device.
61 //
62 template< typename Filter,
63 typename Device,
64 typename Mode =
65 BOOST_DEDUCED_TYPENAME composite_mode<Filter, Device>::type >
66 class composite_device {
67 private:
68 typedef typename detail::param_type<Device>::type param_type;
69 typedef typename mode_of<Filter>::type filter_mode;
70 typedef typename mode_of<Device>::type device_mode;
71 typedef typename
72 iostreams::select< // Disambiguation for Tru64.
73 is_direct<Device>, direct_adapter<Device>,
74 is_std_io<Device>, Device&,
75 else_, Device
76 >::type value_type;
77 BOOST_STATIC_ASSERT(is_filter<Filter>::value);
78 BOOST_STATIC_ASSERT(is_device<Device>::value);
79 public:
80 typedef typename char_type_of<Filter>::type char_type;
81 struct category
82 : Mode,
83 device_tag,
84 closable_tag,
85 flushable_tag,
86 localizable_tag,
87 optimally_buffered_tag
88 { };
89 composite_device(const Filter& flt, param_type dev);
90 std::streamsize read(char_type* s, std::streamsize n);
91 std::streamsize write(const char_type* s, std::streamsize n);
92 std::streampos seek( stream_offset off, BOOST_IOS::seekdir way,
93 BOOST_IOS::openmode which =
94 BOOST_IOS::in | BOOST_IOS::out );
95
96 void close();
97 void close(BOOST_IOS::openmode which);
98 bool flush();
99 std::streamsize optimal_buffer_size() const;
100
101 template<typename Locale> // Avoid dependency on <locale>
imbue(const Locale & loc)102 void imbue(const Locale& loc)
103 {
104 iostreams::imbue(filter_, loc);
105 iostreams::imbue(device_, loc);
106 }
107
first()108 Filter& first() { return filter_; }
second()109 Device& second() { return device_; }
110 private:
111 Filter filter_;
112 value_type device_;
113 };
114
115 //
116 // Template name: composite_device.
117 // Description: Provides a Device view of a Filter, Device pair.
118 // Template parameters:
119 // Filter - A model of Filter.
120 // Device - An indirect model of Device.
121 //
122 template< typename Filter1,
123 typename Filter2,
124 typename Mode =
125 BOOST_DEDUCED_TYPENAME composite_mode<Filter1, Filter2>::type >
126 class composite_filter {
127 private:
128 typedef reference_wrapper<Filter2> filter_ref;
129 typedef typename mode_of<Filter1>::type first_mode;
130 typedef typename mode_of<Filter2>::type second_mode;
131
132 // A dual-use filter cannot be composed with a read-write filter
133 BOOST_STATIC_ASSERT(
134 !(is_convertible<first_mode, dual_use>::value) ||
135 !(is_convertible<second_mode, input>::value) ||
136 !(is_convertible<second_mode, output>::value) ||
137 (is_convertible<second_mode, dual_use>::value)
138 );
139 BOOST_STATIC_ASSERT(
140 !(is_convertible<second_mode, dual_use>::value) ||
141 !(is_convertible<first_mode, input>::value) ||
142 !(is_convertible<first_mode, output>::value) ||
143 (is_convertible<first_mode, dual_use>::value)
144 );
145 BOOST_STATIC_ASSERT(is_filter<Filter1>::value);
146 BOOST_STATIC_ASSERT(is_filter<Filter2>::value);
147 public:
148 typedef typename char_type_of<Filter1>::type char_type;
149 struct category
150 : Mode,
151 filter_tag,
152 multichar_tag,
153 closable_tag,
154 flushable_tag,
155 localizable_tag,
156 optimally_buffered_tag
157 { };
composite_filter(const Filter1 & filter1,const Filter2 & filter2)158 composite_filter(const Filter1& filter1, const Filter2& filter2)
159 : filter1_(filter1), filter2_(filter2)
160 { }
161
162 template<typename Source>
read(Source & src,char_type * s,std::streamsize n)163 std::streamsize read(Source& src, char_type* s, std::streamsize n)
164 {
165 composite_device<filter_ref, Source> cmp(boost::ref(filter2_), src);
166 return iostreams::read(filter1_, cmp, s, n);
167 }
168
169 template<typename Sink>
write(Sink & snk,const char_type * s,std::streamsize n)170 std::streamsize write(Sink& snk, const char_type* s, std::streamsize n)
171 {
172 composite_device<filter_ref, Sink> cmp(boost::ref(filter2_), snk);
173 return iostreams::write(filter1_, cmp, s, n);
174 }
175
176 template<typename Device>
seek(Device & dev,stream_offset off,BOOST_IOS::seekdir way,BOOST_IOS::openmode which=BOOST_IOS::in|BOOST_IOS::out)177 std::streampos seek( Device& dev, stream_offset off, BOOST_IOS::seekdir way,
178 BOOST_IOS::openmode which =
179 BOOST_IOS::in | BOOST_IOS::out )
180 {
181 composite_device<filter_ref, Device> cmp(boost::ref(filter2_), dev);
182 return iostreams::seek(filter1_, cmp, off, way, which);
183 }
184
185 template<typename Device>
close(Device & dev)186 void close(Device& dev)
187 {
188 BOOST_STATIC_ASSERT((!is_convertible<category, two_sequence>::value));
189 BOOST_STATIC_ASSERT((!is_convertible<category, dual_use>::value));
190
191 // Create a new device by composing the second filter2_ with dev.
192 composite_device<filter_ref, Device> cmp(boost::ref(filter2_), dev);
193
194 // Close input sequences in reverse order and output sequences in
195 // forward order
196 if (!is_convertible<first_mode, dual_use>::value) {
197 detail::execute_all(
198 detail::call_close(filter2_, dev, BOOST_IOS::in),
199 detail::call_close(filter1_, cmp, BOOST_IOS::in),
200 detail::call_close(filter1_, cmp, BOOST_IOS::out),
201 detail::call_close(filter2_, dev, BOOST_IOS::out)
202 );
203 } else if (is_convertible<second_mode, input>::value) {
204 detail::execute_all(
205 detail::call_close(filter2_, dev, BOOST_IOS::in),
206 detail::call_close(filter1_, cmp, BOOST_IOS::in)
207 );
208 } else {
209 detail::execute_all(
210 detail::call_close(filter1_, cmp, BOOST_IOS::out),
211 detail::call_close(filter2_, dev, BOOST_IOS::out)
212 );
213 }
214 }
215
216 template<typename Device>
close(Device & dev,BOOST_IOS::openmode which)217 void close(Device& dev, BOOST_IOS::openmode which)
218 {
219 BOOST_STATIC_ASSERT(
220 (is_convertible<category, two_sequence>::value) ||
221 (is_convertible<category, dual_use>::value)
222 );
223
224 // Create a new device by composing the second filter2_ with dev.
225 composite_device<filter_ref, Device> cmp(boost::ref(filter2_), dev);
226
227 // Close input sequences in reverse order
228 if ( which == BOOST_IOS::in &&
229 ( !is_convertible<first_mode, dual_use>::value ||
230 is_convertible<second_mode, input>::value ) )
231 {
232 detail::execute_all(
233 detail::call_close(filter2_, dev, BOOST_IOS::in),
234 detail::call_close(filter1_, cmp, BOOST_IOS::in)
235 );
236 }
237
238 // Close output sequences in forward order
239 if ( which == BOOST_IOS::out &&
240 ( !is_convertible<first_mode, dual_use>::value ||
241 is_convertible<second_mode, output>::value ) )
242 {
243 detail::execute_all(
244 detail::call_close(filter1_, cmp, BOOST_IOS::out),
245 detail::call_close(filter2_, dev, BOOST_IOS::out)
246 );
247 }
248 }
249
250 template<typename Device>
flush(Device & dev)251 bool flush(Device& dev)
252 {
253 composite_device<Filter2, Device> cmp(filter2_, dev);
254 return iostreams::flush(filter1_, cmp);
255 }
256
optimal_buffer_size() const257 std::streamsize optimal_buffer_size() const
258 {
259 std::streamsize first = iostreams::optimal_buffer_size(filter1_);
260 std::streamsize second = iostreams::optimal_buffer_size(filter2_);
261 return first < second ? second : first;
262 }
263
264 template<typename Locale> // Avoid dependency on <locale>
imbue(const Locale & loc)265 void imbue(const Locale& loc)
266 { // To do: consider using RAII.
267 iostreams::imbue(filter1_, loc);
268 iostreams::imbue(filter2_, loc);
269 }
270
first()271 Filter1& first() { return filter1_; }
second()272 Filter2& second() { return filter2_; }
273 private:
274 Filter1 filter1_;
275 Filter2 filter2_;
276 };
277
278 template<typename Filter, typename FilterOrDevice>
279 struct composite_traits
280 : mpl::if_<
281 is_device<FilterOrDevice>,
282 composite_device<Filter, FilterOrDevice>,
283 composite_filter<Filter, FilterOrDevice>
284 >
285 { };
286
287 } // End namespace detail.
288
289 template<typename Filter, typename FilterOrDevice>
290 struct composite : detail::composite_traits<Filter, FilterOrDevice>::type {
291 typedef typename detail::param_type<FilterOrDevice>::type param_type;
292 typedef typename detail::composite_traits<Filter, FilterOrDevice>::type base;
compositeboost::iostreams::composite293 composite(const Filter& flt, param_type dev)
294 : base(flt, dev)
295 { }
296 };
297
298 //--------------Implementation of compose-------------------------------------//
299
300 // Note: The following workarounds are patterned after resolve.hpp. It has not
301 // yet been confirmed that they are necessary.
302
303 #ifndef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION //-------------------------//
304 # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //-------------------------------//
305
306 template<typename Filter, typename FilterOrDevice>
307 composite<Filter, FilterOrDevice>
compose(const Filter & filter,const FilterOrDevice & fod BOOST_IOSTREAMS_DISABLE_IF_STREAM (FilterOrDevice))308 compose( const Filter& filter, const FilterOrDevice& fod
309 BOOST_IOSTREAMS_DISABLE_IF_STREAM(FilterOrDevice) )
310 { return composite<Filter, FilterOrDevice>(filter, fod); }
311
312 template<typename Filter, typename Ch, typename Tr>
313 composite< Filter, std::basic_streambuf<Ch, Tr> >
compose(const Filter & filter,std::basic_streambuf<Ch,Tr> & sb)314 compose(const Filter& filter, std::basic_streambuf<Ch, Tr>& sb)
315 { return composite< Filter, std::basic_streambuf<Ch, Tr> >(filter, sb); }
316
317 template<typename Filter, typename Ch, typename Tr>
318 composite< Filter, std::basic_istream<Ch, Tr> >
compose(const Filter & filter,std::basic_istream<Ch,Tr> & is)319 compose(const Filter& filter, std::basic_istream<Ch, Tr>& is)
320 { return composite< Filter, std::basic_istream<Ch, Tr> >(filter, is); }
321
322 template<typename Filter, typename Ch, typename Tr>
323 composite< Filter, std::basic_ostream<Ch, Tr> >
compose(const Filter & filter,std::basic_ostream<Ch,Tr> & os)324 compose(const Filter& filter, std::basic_ostream<Ch, Tr>& os)
325 { return composite< Filter, std::basic_ostream<Ch, Tr> >(filter, os); }
326
327 template<typename Filter, typename Ch, typename Tr>
328 composite< Filter, std::basic_iostream<Ch, Tr> >
compose(const Filter & filter,std::basic_iostream<Ch,Tr> & io)329 compose(const Filter& filter, std::basic_iostream<Ch, Tr>& io)
330 { return composite< Filter, std::basic_iostream<Ch, Tr> >(filter, io); }
331
332 # else // # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //---------------------//
333
334 template<typename Filter, typename FilterOrDevice>
335 composite<Filter, FilterOrDevice>
compose(const Filter & filter,const FilterOrDevice & fod BOOST_IOSTREAMS_DISABLE_IF_STREAM (FilterOrDevice))336 compose( const Filter& filter, const FilterOrDevice& fod
337 BOOST_IOSTREAMS_DISABLE_IF_STREAM(FilterOrDevice) )
338 { return composite<Filter, FilterOrDevice>(filter, fod); }
339
340 template<typename Filter>
341 composite<Filter, std::streambuf>
compose(const Filter & filter,std::streambuf & sb)342 compose(const Filter& filter, std::streambuf& sb)
343 { return composite<Filter, std::streambuf>(filter, sb); }
344
345 template<typename Filter>
346 composite<Filter, std::istream>
compose(const Filter & filter,std::istream & is)347 compose(const Filter& filter, std::istream& is)
348 { return composite<Filter, std::istream>(filter, is); }
349
350 template<typename Filter>
351 composite<Filter, std::ostream>
compose(const Filter & filter,std::ostream & os)352 compose(const Filter& filter, std::ostream& os)
353 { return composite<Filter, std::ostream>(filter, os); }
354
355 template<typename Filter>
356 composite<Filter, std::iostream>
compose(const Filter & filter,std::iostream & io)357 compose(const Filter& filter, std::iostream& io)
358 { return composite<Filter, std::iostream>(filter, io); }
359
360 # endif // # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //--------------------//
361 #else // #ifndef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION //----------------//
362
363 template<typename Filter, typename Stream>
364 composite<Filter, Stream>
compose(const Filter & flt,const Stream & strm,mpl::true_)365 compose(const Filter& flt, const Stream& strm, mpl::true_)
366 { // Bad overload resolution.
367 return composite<Filter, Stream>(flt, const_cast<Stream&>(strm));
368 }
369
370 template<typename Filter, typename FilterOrDevice>
371 composite<Filter, FilterOrDevice>
compose(const Filter & flt,const FilterOrDevice & fod,mpl::false_)372 compose(const Filter& flt, const FilterOrDevice& fod, mpl::false_)
373 { return composite<Filter, FilterOrDevice>(flt, fod); }
374
375 template<typename Filter, typename FilterOrDevice>
376 composite<Filter, FilterOrDevice>
compose(const Filter & flt,const FilterOrDevice & fod BOOST_IOSTREAMS_DISABLE_IF_STREAM (T))377 compose( const Filter& flt, const FilterOrDevice& fod
378 BOOST_IOSTREAMS_DISABLE_IF_STREAM(T) )
379 { return compose(flt, fod, is_std_io<FilterOrDevice>()); }
380
381 # if !BOOST_WORKAROUND(BOOST_BORLANDC, < 0x600) && \
382 !defined(__GNUC__) // ---------------------------------------------------//
383
384 template<typename Filter, typename FilterOrDevice>
385 composite<Filter, FilterOrDevice>
compose(const Filter & filter,FilterOrDevice & fod)386 compose (const Filter& filter, FilterOrDevice& fod)
387 { return composite<Filter, FilterOrDevice>(filter, fod); }
388
389 # endif // Borland 5.x or GCC //--------------------------------//
390 #endif // #ifndef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION //---------------//
391
392 //----------------------------------------------------------------------------//
393
394 namespace detail {
395
396 //--------------Implementation of composite_device---------------------------//
397
398 template<typename Filter, typename Device, typename Mode>
composite_device(const Filter & flt,param_type dev)399 composite_device<Filter, Device, Mode>::composite_device
400 (const Filter& flt, param_type dev)
401 : filter_(flt), device_(dev)
402 { }
403
404 template<typename Filter, typename Device, typename Mode>
read(char_type * s,std::streamsize n)405 inline std::streamsize composite_device<Filter, Device, Mode>::read
406 (char_type* s, std::streamsize n)
407 { return iostreams::read(filter_, device_, s, n); }
408
409 template<typename Filter, typename Device, typename Mode>
write(const char_type * s,std::streamsize n)410 inline std::streamsize composite_device<Filter, Device, Mode>::write
411 (const char_type* s, std::streamsize n)
412 { return iostreams::write(filter_, device_, s, n); }
413
414 template<typename Filter, typename Device, typename Mode>
seek(stream_offset off,BOOST_IOS::seekdir way,BOOST_IOS::openmode which)415 std::streampos composite_device<Filter, Device, Mode>::seek
416 (stream_offset off, BOOST_IOS::seekdir way, BOOST_IOS::openmode which)
417 { return iostreams::seek(filter_, device_, off, way, which); }
418
419 template<typename Filter, typename Device, typename Mode>
close()420 void composite_device<Filter, Device, Mode>::close()
421 {
422 BOOST_STATIC_ASSERT((!is_convertible<Mode, two_sequence>::value));
423 BOOST_STATIC_ASSERT(
424 !(is_convertible<filter_mode, dual_use>::value) ||
425 !(is_convertible<device_mode, input>::value) ||
426 !(is_convertible<device_mode, output>::value)
427 );
428
429 // Close input sequences in reverse order and output sequences
430 // in forward order
431 if (!is_convertible<filter_mode, dual_use>::value) {
432 detail::execute_all(
433 detail::call_close(device_, BOOST_IOS::in),
434 detail::call_close(filter_, device_, BOOST_IOS::in),
435 detail::call_close(filter_, device_, BOOST_IOS::out),
436 detail::call_close(device_, BOOST_IOS::out)
437 );
438 } else if (is_convertible<device_mode, input>::value) {
439 detail::execute_all(
440 detail::call_close(device_, BOOST_IOS::in),
441 detail::call_close(filter_, device_, BOOST_IOS::in)
442 );
443 } else {
444 detail::execute_all(
445 detail::call_close(filter_, device_, BOOST_IOS::out),
446 detail::call_close(device_, BOOST_IOS::out)
447 );
448 }
449 }
450
451 template<typename Filter, typename Device, typename Mode>
close(BOOST_IOS::openmode which)452 void composite_device<Filter, Device, Mode>::close(BOOST_IOS::openmode which)
453 {
454 BOOST_STATIC_ASSERT((is_convertible<Mode, two_sequence>::value));
455 BOOST_STATIC_ASSERT(!(is_convertible<filter_mode, dual_use>::value));
456
457 // Close input sequences in reverse order
458 if (which == BOOST_IOS::in) {
459 detail::execute_all(
460 detail::call_close(device_, BOOST_IOS::in),
461 detail::call_close(filter_, device_, BOOST_IOS::in)
462 );
463 }
464
465 // Close output sequences in forward order
466 if (which == BOOST_IOS::out) {
467 detail::execute_all(
468 detail::call_close(filter_, device_, BOOST_IOS::out),
469 detail::call_close(device_, BOOST_IOS::out)
470 );
471 }
472 }
473
474 template<typename Filter, typename Device, typename Mode>
flush()475 bool composite_device<Filter, Device, Mode>::flush()
476 {
477 bool r1 = iostreams::flush(filter_, device_);
478 bool r2 = iostreams::flush(device_);
479 return r1 && r2;
480 }
481
482 template<typename Filter, typename Device, typename Mode>
483 std::streamsize
optimal_buffer_size() const484 composite_device<Filter, Device, Mode>::optimal_buffer_size() const
485 { return iostreams::optimal_buffer_size(device_); }
486
487 } // End namespace detail.
488
489 } } // End namespaces iostreams, boost.
490
491 #include <boost/iostreams/detail/config/enable_warnings.hpp>
492
493 #endif // #ifndef BOOST_IOSTREAMS_COMPOSE_HPP_INCLUDED
494