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) && (_MSC_VER >= 1020)
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
36namespace boost { namespace iostreams {
37
38namespace detail {
39
40template< 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 >
46struct 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//
62template< typename Filter,
63 typename Device,
64 typename Mode =
65 BOOST_DEDUCED_TYPENAME composite_mode<Filter, Device>::type >
66class composite_device {
67private:
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);
79public:
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>
102 void imbue(const Locale& loc)
103 {
104 iostreams::imbue(filter_, loc);
105 iostreams::imbue(device_, loc);
106 }
107
108 Filter& first() { return filter_; }
109 Device& second() { return device_; }
110private:
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//
122template< typename Filter1,
123 typename Filter2,
124 typename Mode =
125 BOOST_DEDUCED_TYPENAME composite_mode<Filter1, Filter2>::type >
126class composite_filter {
127private:
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);
147public:
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 { };
158 composite_filter(const Filter1& filter1, const Filter2& filter2)
159 : filter1_(filter1), filter2_(filter2)
160 { }
161
162 template<typename Source>
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>
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>
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>
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>
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>
251 bool flush(Device& dev)
252 {
253 composite_device<Filter2, Device> cmp(filter2_, dev);
254 return iostreams::flush(filter1_, cmp);
255 }
256
257 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>
265 void imbue(const Locale& loc)
266 { // To do: consider using RAII.
267 iostreams::imbue(filter1_, loc);
268 iostreams::imbue(filter2_, loc);
269 }
270
271 Filter1& first() { return filter1_; }
272 Filter2& second() { return filter2_; }
273private:
274 Filter1 filter1_;
275 Filter2 filter2_;
276};
277
278template<typename Filter, typename FilterOrDevice>
279struct 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
289template<typename Filter, typename FilterOrDevice>
290struct 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;
293 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
306template<typename Filter, typename FilterOrDevice>
307composite<Filter, FilterOrDevice>
308compose( const Filter& filter, const FilterOrDevice& fod
309 BOOST_IOSTREAMS_DISABLE_IF_STREAM(FilterOrDevice) )
310{ return composite<Filter, FilterOrDevice>(filter, fod); }
311
312template<typename Filter, typename Ch, typename Tr>
313composite< Filter, std::basic_streambuf<Ch, Tr> >
314compose(const Filter& filter, std::basic_streambuf<Ch, Tr>& sb)
315{ return composite< Filter, std::basic_streambuf<Ch, Tr> >(filter, sb); }
316
317template<typename Filter, typename Ch, typename Tr>
318composite< Filter, std::basic_istream<Ch, Tr> >
319compose(const Filter& filter, std::basic_istream<Ch, Tr>& is)
320{ return composite< Filter, std::basic_istream<Ch, Tr> >(filter, is); }
321
322template<typename Filter, typename Ch, typename Tr>
323composite< Filter, std::basic_ostream<Ch, Tr> >
324compose(const Filter& filter, std::basic_ostream<Ch, Tr>& os)
325{ return composite< Filter, std::basic_ostream<Ch, Tr> >(filter, os); }
326
327template<typename Filter, typename Ch, typename Tr>
328composite< Filter, std::basic_iostream<Ch, Tr> >
329compose(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
334template<typename Filter, typename FilterOrDevice>
335composite<Filter, FilterOrDevice>
336compose( const Filter& filter, const FilterOrDevice& fod
337 BOOST_IOSTREAMS_DISABLE_IF_STREAM(FilterOrDevice) )
338{ return composite<Filter, FilterOrDevice>(filter, fod); }
339
340template<typename Filter>
341composite<Filter, std::streambuf>
342compose(const Filter& filter, std::streambuf& sb)
343{ return composite<Filter, std::streambuf>(filter, sb); }
344
345template<typename Filter>
346composite<Filter, std::istream>
347compose(const Filter& filter, std::istream& is)
348{ return composite<Filter, std::istream>(filter, is); }
349
350template<typename Filter>
351composite<Filter, std::ostream>
352compose(const Filter& filter, std::ostream& os)
353{ return composite<Filter, std::ostream>(filter, os); }
354
355template<typename Filter>
356composite<Filter, std::iostream>
357compose(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
363template<typename Filter, typename Stream>
364composite<Filter, Stream>
365compose(const Filter& flt, const Stream& strm, mpl::true_)
366{ // Bad overload resolution.
367 return composite<Filter, Stream>(flt, const_cast<Stream&>(strm));
368}
369
370template<typename Filter, typename FilterOrDevice>
371composite<Filter, FilterOrDevice>
372compose(const Filter& flt, const FilterOrDevice& fod, mpl::false_)
373{ return composite<Filter, FilterOrDevice>(flt, fod); }
374
375template<typename Filter, typename FilterOrDevice>
376composite<Filter, FilterOrDevice>
377compose( 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(__BORLANDC__, < 0x600) && \
382 !BOOST_WORKAROUND(BOOST_MSVC, <= 1300) && \
383 !defined(__GNUC__) // ---------------------------------------------------//
384
385template<typename Filter, typename FilterOrDevice>
386composite<Filter, FilterOrDevice>
387compose (const Filter& filter, FilterOrDevice& fod)
388{ return composite<Filter, FilterOrDevice>(filter, fod); }
389
390# endif // Borland 5.x, VC6-7.0 or GCC 2.9x //--------------------------------//
391#endif // #ifndef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION //---------------//
392
393//----------------------------------------------------------------------------//
394
395namespace detail {
396
397//--------------Implementation of composite_device---------------------------//
398
399template<typename Filter, typename Device, typename Mode>
400composite_device<Filter, Device, Mode>::composite_device
401 (const Filter& flt, param_type dev)
402 : filter_(flt), device_(dev)
403 { }
404
405template<typename Filter, typename Device, typename Mode>
406inline std::streamsize composite_device<Filter, Device, Mode>::read
407 (char_type* s, std::streamsize n)
408{ return iostreams::read(filter_, device_, s, n); }
409
410template<typename Filter, typename Device, typename Mode>
411inline std::streamsize composite_device<Filter, Device, Mode>::write
412 (const char_type* s, std::streamsize n)
413{ return iostreams::write(filter_, device_, s, n); }
414
415template<typename Filter, typename Device, typename Mode>
416std::streampos composite_device<Filter, Device, Mode>::seek
417 (stream_offset off, BOOST_IOS::seekdir way, BOOST_IOS::openmode which)
418{ return iostreams::seek(filter_, device_, off, way, which); }
419
420template<typename Filter, typename Device, typename Mode>
421void composite_device<Filter, Device, Mode>::close()
422{
423 BOOST_STATIC_ASSERT((!is_convertible<Mode, two_sequence>::value));
424 BOOST_STATIC_ASSERT(
425 !(is_convertible<filter_mode, dual_use>::value) ||
426 !(is_convertible<device_mode, input>::value) ||
427 !(is_convertible<device_mode, output>::value)
428 );
429
430 // Close input sequences in reverse order and output sequences
431 // in forward order
432 if (!is_convertible<filter_mode, dual_use>::value) {
433 detail::execute_all(
434 detail::call_close(device_, BOOST_IOS::in),
435 detail::call_close(filter_, device_, BOOST_IOS::in),
436 detail::call_close(filter_, device_, BOOST_IOS::out),
437 detail::call_close(device_, BOOST_IOS::out)
438 );
439 } else if (is_convertible<device_mode, input>::value) {
440 detail::execute_all(
441 detail::call_close(device_, BOOST_IOS::in),
442 detail::call_close(filter_, device_, BOOST_IOS::in)
443 );
444 } else {
445 detail::execute_all(
446 detail::call_close(filter_, device_, BOOST_IOS::out),
447 detail::call_close(device_, BOOST_IOS::out)
448 );
449 }
450}
451
452template<typename Filter, typename Device, typename Mode>
453void composite_device<Filter, Device, Mode>::close(BOOST_IOS::openmode which)
454{
455 BOOST_STATIC_ASSERT((is_convertible<Mode, two_sequence>::value));
456 BOOST_STATIC_ASSERT(!(is_convertible<filter_mode, dual_use>::value));
457
458 // Close input sequences in reverse order
459 if (which == BOOST_IOS::in) {
460 detail::execute_all(
461 detail::call_close(device_, BOOST_IOS::in),
462 detail::call_close(filter_, device_, BOOST_IOS::in)
463 );
464 }
465
466 // Close output sequences in forward order
467 if (which == BOOST_IOS::out) {
468 detail::execute_all(
469 detail::call_close(filter_, device_, BOOST_IOS::out),
470 detail::call_close(device_, BOOST_IOS::out)
471 );
472 }
473}
474
475template<typename Filter, typename Device, typename Mode>
476bool composite_device<Filter, Device, Mode>::flush()
477{
478 bool r1 = iostreams::flush(filter_, device_);
479 bool r2 = iostreams::flush(device_);
480 return r1 && r2;
481}
482
483template<typename Filter, typename Device, typename Mode>
484std::streamsize
485composite_device<Filter, Device, Mode>::optimal_buffer_size() const
486{ return iostreams::optimal_buffer_size(device_); }
487
488} // End namespace detail.
489
490} } // End namespaces iostreams, boost.
491
492#include <boost/iostreams/detail/config/enable_warnings.hpp>
493
494#endif // #ifndef BOOST_IOSTREAMS_COMPOSE_HPP_INCLUDED
495

source code of boost/boost/iostreams/compose.hpp