boost/iostreams/combine.hpp
// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) // (C) Copyright 2003-2007 Jonathan Turkanis // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) // See http://www.boost.org/libs/iostreams for documentation. // To do: add support for random-access. #ifndef BOOST_IOSTREAMS_COMBINE_HPP_INCLUDED #define BOOST_IOSTREAMS_COMBINE_HPP_INCLUDED #if defined(_MSC_VER) && (_MSC_VER >= 1020) # pragma once #endif #include <boost/config.hpp> // NO_STD_LOCALE, DEDUCED_TYPENAME. #ifndef BOOST_NO_STD_LOCALE # include <locale> #endif #include <boost/iostreams/detail/ios.hpp> #include <boost/iostreams/detail/wrap_unwrap.hpp> #include <boost/iostreams/traits.hpp> #include <boost/iostreams/operations.hpp> #include <boost/mpl/if.hpp> #include <boost/static_assert.hpp> #include <boost/type_traits/is_convertible.hpp> #include <boost/type_traits/is_same.hpp> // Must come last. #include <boost/iostreams/detail/config/disable_warnings.hpp> namespace boost { namespace iostreams { namespace detail { // // Template name: combined_device. // Description: Model of Device defined in terms of a Source/Sink pair. // Template paramters: // Source - A model of Source, with the same char_type and traits_type // as Sink. // Sink - A model of Sink, with the same char_type and traits_type // as Source. // template<typename Source, typename Sink> class combined_device { private: typedef typename category_of<Source>::type in_category; typedef typename category_of<Sink>::type out_category; typedef typename char_type_of<Sink>::type sink_char_type; public: typedef typename char_type_of<Source>::type char_type; struct category : bidirectional, device_tag, closable_tag, localizable_tag { }; BOOST_STATIC_ASSERT(is_device<Source>::value); BOOST_STATIC_ASSERT(is_device<Sink>::value); BOOST_STATIC_ASSERT((is_convertible<in_category, input>::value)); BOOST_STATIC_ASSERT((is_convertible<out_category, output>::value)); BOOST_STATIC_ASSERT((is_same<char_type, sink_char_type>::value)); combined_device(const Source& src, const Sink& snk); std::streamsize read(char_type* s, std::streamsize n); std::streamsize write(const char_type* s, std::streamsize n); void close(BOOST_IOS::openmode); #ifndef BOOST_NO_STD_LOCALE void imbue(const std::locale& loc); #endif private: Source src_; Sink sink_; }; // // Template name: combined_filter. // Description: Model of Device defined in terms of a Source/Sink pair. // Template paramters: // InputFilter - A model of InputFilter, with the same char_type as // OutputFilter. // OutputFilter - A model of OutputFilter, with the same char_type as // InputFilter. // template<typename InputFilter, typename OutputFilter> class combined_filter { private: typedef typename category_of<InputFilter>::type in_category; typedef typename category_of<OutputFilter>::type out_category; typedef typename char_type_of<OutputFilter>::type output_char_type; public: typedef typename char_type_of<InputFilter>::type char_type; struct category : multichar_bidirectional_filter_tag, closable_tag, localizable_tag { }; BOOST_STATIC_ASSERT(is_filter<InputFilter>::value); BOOST_STATIC_ASSERT(is_filter<OutputFilter>::value); BOOST_STATIC_ASSERT((is_convertible<in_category, input>::value)); BOOST_STATIC_ASSERT((is_convertible<out_category, output>::value)); BOOST_STATIC_ASSERT((is_same<char_type, output_char_type>::value)); combined_filter(const InputFilter& in, const OutputFilter& out); template<typename Source> std::streamsize read(Source& src, char_type* s, std::streamsize n) { return boost::iostreams::read(in_, src, s, n); } template<typename Sink> std::streamsize write(Sink& snk, const char_type* s, std::streamsize n) { return boost::iostreams::write(out_, snk, s, n); } template<typename Sink> void close(Sink& snk, BOOST_IOS::openmode which) { if (which == BOOST_IOS::in) { if (is_convertible<in_category, dual_use>::value) { iostreams::close(in_, snk, BOOST_IOS::in); } else { detail::close_all(in_, snk); } } if (which == BOOST_IOS::out) { if (is_convertible<out_category, dual_use>::value) { iostreams::close(out_, snk, BOOST_IOS::out); } else { detail::close_all(out_, snk); } } } #ifndef BOOST_NO_STD_LOCALE void imbue(const std::locale& loc); #endif private: InputFilter in_; OutputFilter out_; }; template<typename In, typename Out> struct combination_traits : mpl::if_< is_device<In>, combined_device< typename wrapped_type<In>::type, typename wrapped_type<Out>::type >, combined_filter< typename wrapped_type<In>::type, typename wrapped_type<Out>::type > > { }; } // End namespace detail. template<typename In, typename Out> struct combination : detail::combination_traits<In, Out>::type { typedef typename detail::combination_traits<In, Out>::type base_type; typedef typename detail::wrapped_type<In>::type in_type; typedef typename detail::wrapped_type<Out>::type out_type; combination(const in_type& in, const out_type& out) : base_type(in, out) { } }; namespace detail { // Workaround for VC6 ETI bug. template<typename In, typename Out> struct combine_traits { typedef combination< BOOST_DEDUCED_TYPENAME detail::unwrapped_type<In>::type, BOOST_DEDUCED_TYPENAME detail::unwrapped_type<Out>::type > type; }; } // End namespace detail. // // Template name: combine. // Description: Takes a Source/Sink pair or InputFilter/OutputFilter pair and // returns a Reource or Filter which performs input using the first member // of the pair and output using the second member of the pair. // Template paramters: // In - A model of Source or InputFilter, with the same char_type as Out. // Out - A model of Sink or OutputFilter, with the same char_type as In. // template<typename In, typename Out> typename detail::combine_traits<In, Out>::type combine(const In& in, const Out& out) { typedef typename detail::combine_traits<In, Out>::type return_type; return return_type(in, out); } //----------------------------------------------------------------------------// namespace detail { //--------------Implementation of combined_device-----------------------------// template<typename Source, typename Sink> inline combined_device<Source, Sink>::combined_device (const Source& src, const Sink& snk) : src_(src), sink_(snk) { } template<typename Source, typename Sink> inline std::streamsize combined_device<Source, Sink>::read(char_type* s, std::streamsize n) { return iostreams::read(src_, s, n); } template<typename Source, typename Sink> inline std::streamsize combined_device<Source, Sink>::write(const char_type* s, std::streamsize n) { return iostreams::write(sink_, s, n); } template<typename Source, typename Sink> inline void combined_device<Source, Sink>::close(BOOST_IOS::openmode which) { if (which == BOOST_IOS::in) detail::close_all(src_); if (which == BOOST_IOS::out) detail::close_all(sink_); } #ifndef BOOST_NO_STD_LOCALE template<typename Source, typename Sink> void combined_device<Source, Sink>::imbue(const std::locale& loc) { iostreams::imbue(src_, loc); iostreams::imbue(sink_, loc); } #endif //--------------Implementation of filter_pair---------------------------------// template<typename InputFilter, typename OutputFilter> inline combined_filter<InputFilter, OutputFilter>::combined_filter (const InputFilter& in, const OutputFilter& out) : in_(in), out_(out) { } #ifndef BOOST_NO_STD_LOCALE template<typename InputFilter, typename OutputFilter> void combined_filter<InputFilter, OutputFilter>::imbue (const std::locale& loc) { iostreams::imbue(in_, loc); iostreams::imbue(out_, loc); } #endif } // End namespace detail. } } // End namespaces iostreams, boost. #include <boost/iostreams/detail/config/enable_warnings.hpp> #endif // #ifndef BOOST_IOSTREAMS_COMBINE_HPP_INCLUDED