sl@0: // (C) Copyright Jonathan Turkanis 2005.
sl@0: // Distributed under the Boost Software License, Version 1.0. (See accompanying
sl@0: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
sl@0: 
sl@0: // See http://www.boost.org/libs/iostreams for documentation.
sl@0: 
sl@0: // Note: bidirectional streams are not supported.
sl@0: 
sl@0: #ifndef BOOST_IOSTREAMS_COMPOSE_HPP_INCLUDED
sl@0: #define BOOST_IOSTREAMS_COMPOSE_HPP_INCLUDED
sl@0: 
sl@0: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
sl@0: # pragma once
sl@0: #endif
sl@0: 
sl@0: #include <algorithm>          // min.
sl@0: #include <utility>            // pair.
sl@0: #include <boost/config.hpp>   // DEDUCED_TYPENAME.
sl@0: #include <boost/iostreams/categories.hpp>
sl@0: #include <boost/iostreams/detail/adapter/direct_adapter.hpp>
sl@0: #include <boost/iostreams/detail/call_traits.hpp>
sl@0: #include <boost/iostreams/detail/closer.hpp>
sl@0: #include <boost/iostreams/detail/enable_if_stream.hpp>
sl@0: #include <boost/iostreams/operations.hpp>
sl@0: #include <boost/iostreams/traits.hpp>      // mode_of, is_direct.
sl@0: #include <boost/mpl/if.hpp>
sl@0: #include <boost/ref.hpp>
sl@0: #include <boost/static_assert.hpp>
sl@0: #include <boost/type_traits/is_convertible.hpp>
sl@0: 
sl@0: namespace boost { namespace iostreams {
sl@0: 
sl@0: namespace detail {
sl@0: 
sl@0: template<typename Filter, typename Device>
sl@0: struct composite_mode {
sl@0:     typedef typename mode_of<Filter>::type           filter_mode;
sl@0:     typedef typename mode_of<Device>::type           device_mode;
sl@0:     typedef is_convertible<filter_mode, dual_use>    is_dual_use;
sl@0:     typedef typename
sl@0:             mpl::if_<
sl@0:                 is_convertible<device_mode, input>,
sl@0:                 input,
sl@0:                 output
sl@0:             >::type                                  type;
sl@0: };
sl@0: 
sl@0: //
sl@0: // Template name: composite_device.
sl@0: // Description: Provides a Device view of a Filter, Device pair.
sl@0: // Template paramters:
sl@0: //      Filter - A model of Filter.
sl@0: //      Device - An indirect model of Device.
sl@0: //
sl@0: template< typename Filter,
sl@0:           typename Device,
sl@0:           typename Mode =
sl@0:               BOOST_DEDUCED_TYPENAME composite_mode<Filter, Device>::type >
sl@0: class composite_device {
sl@0: private:
sl@0:     typedef typename detail::param_type<Device>::type       param_type;
sl@0:     typedef typename
sl@0:             iostreams::select<  // Disambiguation for Tru64.
sl@0:                 is_direct<Device>,  direct_adapter<Device>,
sl@0:                 is_std_io<Device>,  Device&,
sl@0:                 else_,              Device
sl@0:             >::type                                         value_type;
sl@0: public:
sl@0:     typedef typename char_type_of<Filter>::type             char_type;
sl@0:     struct category
sl@0:         : Mode,
sl@0:           device_tag,
sl@0:           closable_tag,
sl@0:           flushable_tag,
sl@0:           localizable_tag,
sl@0:           optimally_buffered_tag
sl@0:         { };
sl@0:     composite_device(const Filter& flt, param_type dev);
sl@0:     std::streamsize read(char_type* s, std::streamsize n);
sl@0:     std::streamsize write(const char_type* s, std::streamsize n);
sl@0:     stream_offset seek( stream_offset off, BOOST_IOS::seekdir way,
sl@0:                         BOOST_IOS::openmode which =
sl@0:                             BOOST_IOS::in | BOOST_IOS::out );
sl@0: 
sl@0:     void close();
sl@0:     void close(BOOST_IOS::openmode which);
sl@0:     bool flush();
sl@0:     std::streamsize optimal_buffer_size() const;
sl@0: 
sl@0:     template<typename Locale> // Avoid dependency on <locale>
sl@0:     void imbue(const Locale& loc)
sl@0:     {
sl@0:         iostreams::imbue(filter_, loc);
sl@0:         iostreams::imbue(device_, loc);
sl@0:     }
sl@0: 
sl@0:     Filter& first() { return filter_; }
sl@0:     Device& second() { return device_; }
sl@0: private:
sl@0:     Filter      filter_;
sl@0:     value_type  device_;
sl@0: };
sl@0: 
sl@0: //
sl@0: // Template name: composite_device.
sl@0: // Description: Provides a Device view of a Filter, Device pair.
sl@0: // Template paramters:
sl@0: //      Filter - A model of Filter.
sl@0: //      Device - An indirect model of Device.
sl@0: //
sl@0: template<typename Filter1, typename Filter2>
sl@0: class composite_filter {
sl@0: private:
sl@0:      typedef reference_wrapper<Filter2>           filter_ref;
sl@0: public:
sl@0:     typedef typename char_type_of<Filter1>::type  char_type;
sl@0:     struct category
sl@0:         : mode_of<Filter1>::type,
sl@0:           filter_tag,
sl@0:           multichar_tag,
sl@0:           closable_tag,
sl@0:           flushable_tag,
sl@0:           localizable_tag,
sl@0:           optimally_buffered_tag
sl@0:         { };
sl@0:     composite_filter(const Filter1& filter1, const Filter2& filter2)
sl@0:         : filter1_(filter1), filter2_(filter2)
sl@0:         { }
sl@0: 
sl@0:     template<typename Source>
sl@0:     std::streamsize read(Source& src, char_type* s, std::streamsize n)
sl@0:     {
sl@0:         composite_device<filter_ref, Source> cmp(boost::ref(filter2_), src);
sl@0:         return iostreams::read(filter1_, cmp, s, n);
sl@0:     }
sl@0: 
sl@0:     template<typename Sink>
sl@0:     std::streamsize write(Sink& snk, const char_type* s, std::streamsize n)
sl@0:     {
sl@0:         composite_device<filter_ref, Sink> cmp(boost::ref(filter2_), snk);
sl@0:         return iostreams::write(filter1_, cmp, s, n);
sl@0:     }
sl@0: 
sl@0:     template<typename Device>
sl@0:     stream_offset seek( Device& dev, stream_offset off, BOOST_IOS::seekdir way,
sl@0:                         BOOST_IOS::openmode which =
sl@0:                             BOOST_IOS::in | BOOST_IOS::out )
sl@0:     {
sl@0:         composite_device<filter_ref, Device> cmp(boost::ref(filter2_), dev);
sl@0:         return iostreams::seek(filter1_, cmp, off, way, which);
sl@0:     }
sl@0: 
sl@0:     template<typename Device>
sl@0:     void close( Device& dev,
sl@0:                 BOOST_IOS::openmode which =
sl@0:                     BOOST_IOS::in | BOOST_IOS::out )
sl@0:     {
sl@0:         composite_device<filter_ref, Device> cmp(boost::ref(filter2_), dev);
sl@0:         iostreams::close(filter1_, cmp, which);
sl@0:     }
sl@0: 
sl@0:     template<typename Device>
sl@0:     bool flush(Device& dev)
sl@0:     {
sl@0:         composite_device<Filter2, Device> cmp(filter2_, dev);
sl@0:         return iostreams::flush(filter1_, cmp);
sl@0:     }
sl@0: 
sl@0:     std::streamsize optimal_buffer_size() const
sl@0:     {
sl@0:         std::streamsize first = iostreams::optimal_buffer_size(filter1_);
sl@0:         std::streamsize second = iostreams::optimal_buffer_size(filter2_);
sl@0:         return first < second ? second : first;
sl@0:     }
sl@0: 
sl@0:     template<typename Locale> // Avoid dependency on <locale>
sl@0:     void imbue(const Locale& loc)
sl@0:     {   // To do: consider using RAII.
sl@0:         iostreams::imbue(filter1_, loc);
sl@0:         iostreams::imbue(filter2_, loc);
sl@0:     }
sl@0: 
sl@0:     Filter1& first() { return filter1_; }
sl@0:     Filter2& second() { return filter2_; }
sl@0: private:
sl@0:     Filter1  filter1_;
sl@0:     Filter2  filter2_;
sl@0: };
sl@0: 
sl@0: template<typename Filter, typename FilterOrDevice>
sl@0: struct composite_traits
sl@0:     : mpl::if_<
sl@0:           is_device<FilterOrDevice>,
sl@0:           composite_device<Filter, FilterOrDevice>,
sl@0:           composite_filter<Filter, FilterOrDevice>
sl@0:       >
sl@0:     { };
sl@0: 
sl@0: } // End namespace detail.
sl@0: 
sl@0: template<typename Filter, typename FilterOrDevice>
sl@0: struct composite : detail::composite_traits<Filter, FilterOrDevice>::type {
sl@0:     typedef typename detail::param_type<FilterOrDevice>::type param_type;
sl@0:     typedef typename detail::composite_traits<Filter, FilterOrDevice>::type base;
sl@0:     composite(const Filter& flt, param_type dev)
sl@0:         : base(flt, dev)
sl@0:         { }
sl@0: };
sl@0: 
sl@0: //--------------Implementation of compose-------------------------------------//
sl@0: 
sl@0: // Note: The following workarounds are patterned after resolve.hpp. It has not
sl@0: // yet been confirmed that they are necessary.
sl@0: 
sl@0: #ifndef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION //-------------------------//
sl@0: # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //-------------------------------//
sl@0: 
sl@0: template<typename Filter, typename FilterOrDevice>
sl@0: composite<Filter, FilterOrDevice>
sl@0: compose( const Filter& filter, const FilterOrDevice& fod
sl@0:          BOOST_IOSTREAMS_DISABLE_IF_STREAM(FilterOrDevice) )
sl@0: { return composite<Filter, FilterOrDevice>(filter, fod); }
sl@0: 
sl@0: template<typename Filter, typename Ch, typename Tr>
sl@0: composite< Filter, std::basic_streambuf<Ch, Tr> >
sl@0: compose(const Filter& filter, std::basic_streambuf<Ch, Tr>& sb)
sl@0: { return composite< Filter, std::basic_streambuf<Ch, Tr> >(filter, sb); }
sl@0: 
sl@0: template<typename Filter, typename Ch, typename Tr>
sl@0: composite< Filter, std::basic_istream<Ch, Tr> >
sl@0: compose(const Filter& filter, std::basic_istream<Ch, Tr>& is)
sl@0: { return composite< Filter, std::basic_istream<Ch, Tr> >(filter, is); }
sl@0: 
sl@0: template<typename Filter, typename Ch, typename Tr>
sl@0: composite< Filter, std::basic_ostream<Ch, Tr> >
sl@0: compose(const Filter& filter, std::basic_ostream<Ch, Tr>& os)
sl@0: { return composite< Filter, std::basic_ostream<Ch, Tr> >(filter, os); }
sl@0: 
sl@0: template<typename Filter, typename Ch, typename Tr>
sl@0: composite< Filter, std::basic_iostream<Ch, Tr> >
sl@0: compose(const Filter& filter, std::basic_iostream<Ch, Tr>& io)
sl@0: { return composite< Filter, std::basic_iostream<Ch, Tr> >(filter, io); }
sl@0: 
sl@0: # else // # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //---------------------//
sl@0: 
sl@0: template<typename Filter, typename FilterOrDevice>
sl@0: composite<Filter, FilterOrDevice>
sl@0: compose( const Filter& filter, const FilterOrDevice& fod
sl@0:          BOOST_IOSTREAMS_DISABLE_IF_STREAM(FilterOrDevice) )
sl@0: { return composite<Filter, FilterOrDevice>(filter, fod); }
sl@0: 
sl@0: template<typename Filter>
sl@0: composite<Filter, std::streambuf>
sl@0: compose(const Filter& filter, std::streambuf& sb)
sl@0: { return composite<Filter, std::streambuf>(filter, sb); }
sl@0: 
sl@0: template<typename Filter>
sl@0: composite<Filter, std::istream>
sl@0: compose(const Filter& filter, std::istream& is)
sl@0: { return composite<Filter, std::istream>(filter, is); }
sl@0: 
sl@0: template<typename Filter>
sl@0: composite<Filter, std::ostream>
sl@0: compose(const Filter& filter, std::ostream& os)
sl@0: { return composite<Filter, std::ostream>(filter, os); }
sl@0: 
sl@0: template<typename Filter>
sl@0: composite<Filter, std::iostream>
sl@0: compose(const Filter& filter, std::iostream& io)
sl@0: { return composite<Filter, std::iostream>(filter, io); }
sl@0: 
sl@0: # endif // # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //--------------------//
sl@0: #else // #ifndef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION //----------------//
sl@0: 
sl@0: template<typename Filter, typename Stream>
sl@0: composite<Filter, Stream>
sl@0: compose(const Filter& flt, const Stream& strm, mpl::true_)
sl@0: {   // Bad overload resolution.
sl@0:     return composite<Filter, Stream>(flt, const_cast<Stream&>(strm));
sl@0: }
sl@0: 
sl@0: template<typename Filter, typename FilterOrDevice>
sl@0: composite<Filter, FilterOrDevice>
sl@0: compose(const Filter& flt, const FilterOrDevice& fod, mpl::false_)
sl@0: { return composite<Filter, FilterOrDevice>(flt, fod); }
sl@0: 
sl@0: template<typename Filter, typename FilterOrDevice>
sl@0: composite<Filter, FilterOrDevice>
sl@0: compose( const Filter& flt, const FilterOrDevice& fod
sl@0:          BOOST_IOSTREAMS_DISABLE_IF_STREAM(T) )
sl@0: { return compose(flt, fod, is_std_io<FilterOrDevice>()); }
sl@0: 
sl@0: # if !BOOST_WORKAROUND(__BORLANDC__, < 0x600) && \
sl@0:      !BOOST_WORKAROUND(BOOST_MSVC, <= 1300) && \
sl@0:      !defined(__GNUC__) // ---------------------------------------------------//
sl@0: 
sl@0: template<typename Filter, typename FilterOrDevice>
sl@0: composite<Filter, FilterOrDevice>
sl@0: compose (const Filter& filter, FilterOrDevice& fod)
sl@0: { return composite<Filter, FilterOrDevice>(filter, fod); }
sl@0: 
sl@0: # endif // Borland 5.x, VC6-7.0 or GCC 2.9x //--------------------------------//
sl@0: #endif // #ifndef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION //---------------//
sl@0: 
sl@0: //----------------------------------------------------------------------------//
sl@0: 
sl@0: namespace detail {
sl@0: 
sl@0: //--------------Implementation of composite_device---------------------------//
sl@0: 
sl@0: template<typename Filter, typename Device, typename Mode>
sl@0: composite_device<Filter, Device, Mode>::composite_device
sl@0:     (const Filter& flt, param_type dev)
sl@0:     : filter_(flt), device_(dev)
sl@0:     { }
sl@0: 
sl@0: template<typename Filter, typename Device, typename Mode>
sl@0: inline std::streamsize composite_device<Filter, Device, Mode>::read
sl@0:     (char_type* s, std::streamsize n)
sl@0: { return iostreams::read(filter_, device_, s, n); }
sl@0: 
sl@0: template<typename Filter, typename Device, typename Mode>
sl@0: inline std::streamsize composite_device<Filter, Device, Mode>::write
sl@0:     (const char_type* s, std::streamsize n)
sl@0: { return iostreams::write(filter_, device_, s, n); }
sl@0: 
sl@0: template<typename Filter, typename Device, typename Mode>
sl@0: stream_offset composite_device<Filter, Device, Mode>::seek
sl@0:     (stream_offset off, BOOST_IOS::seekdir way, BOOST_IOS::openmode which)
sl@0: { return iostreams::seek(filter_, device_, off, way, which); }
sl@0: 
sl@0: template<typename Filter, typename Device, typename Mode>
sl@0: void composite_device<Filter, Device, Mode>::close()
sl@0: {
sl@0:     typedef typename mode_of<Device>::type device_mode;
sl@0:     BOOST_IOS::openmode which =
sl@0:         is_convertible<device_mode, input>() ?
sl@0:             BOOST_IOS::in :
sl@0:             BOOST_IOS::out;
sl@0:     close(which);
sl@0: }
sl@0: 
sl@0: template<typename Filter, typename Device, typename Mode>
sl@0: void composite_device<Filter, Device, Mode>::close(BOOST_IOS::openmode which)
sl@0: {
sl@0:     bool                                 nothrow = false;
sl@0:     external_closer<value_type>          close_device(device_, which, nothrow);
sl@0:     external_closer<Filter, value_type>  close_filter(filter_, device_, which, nothrow);
sl@0: }
sl@0: 
sl@0: template<typename Filter, typename Device, typename Mode>
sl@0: bool composite_device<Filter, Device, Mode>::flush()
sl@0: {   // To do: consider using RAII.
sl@0:     bool r1 = iostreams::flush(filter_, device_);
sl@0:     bool r2 = iostreams::flush(device_);
sl@0:     return r1 && r2;
sl@0: }
sl@0: 
sl@0: template<typename Filter, typename Device, typename Mode>
sl@0: std::streamsize
sl@0: composite_device<Filter, Device, Mode>::optimal_buffer_size() const
sl@0: { return iostreams::optimal_buffer_size(device_); }
sl@0: 
sl@0: } // End namespace detail.
sl@0: 
sl@0: } } // End namespaces iostreams, boost.
sl@0: 
sl@0: #endif // #ifndef BOOST_IOSTREAMS_COMPOSE_HPP_INCLUDED