sl@0: // (C) Copyright Jonathan Turkanis 2003.
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: #ifndef BOOST_IOSTREAMS_INVERT_HPP_INCLUDED
sl@0: #define BOOST_IOSTREAMS_INVERT_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>                             // copy, min.  
sl@0: #include <cassert>
sl@0: #include <boost/config.hpp>                      // BOOST_DEDUCED_TYPENAME.       
sl@0: #include <boost/detail/workaround.hpp>           // default_filter_buffer_size.
sl@0: #include <boost/iostreams/char_traits.hpp>
sl@0: #include <boost/iostreams/compose.hpp>
sl@0: #include <boost/iostreams/constants.hpp>
sl@0: #include <boost/iostreams/device/array.hpp>
sl@0: #include <boost/iostreams/detail/buffer.hpp>
sl@0: #include <boost/iostreams/detail/counted_array.hpp>
sl@0: #include <boost/mpl/if.hpp>
sl@0: #include <boost/ref.hpp>
sl@0: #include <boost/shared_ptr.hpp>
sl@0: #include <boost/type_traits/is_convertible.hpp>
sl@0: 
sl@0: // Must come last.
sl@0: #include <boost/iostreams/detail/config/disable_warnings.hpp>  // MSVC.
sl@0: 
sl@0: namespace boost { namespace iostreams {
sl@0: 
sl@0: //
sl@0: // Template name: inverse.
sl@0: // Template paramters:
sl@0: //      Filter - A filter adapter which 
sl@0: // Description: Returns an instance of an appropriate specialization of inverse.
sl@0: //
sl@0: template<typename Filter>
sl@0: class inverse {
sl@0: private:
sl@0:     typedef typename category_of<Filter>::type   base_category;
sl@0:     typedef reference_wrapper<Filter>            filter_ref;
sl@0: public:
sl@0:     typedef typename char_type_of<Filter>::type  char_type;
sl@0:     typedef typename int_type_of<Filter>::type   int_type;
sl@0:     typedef char_traits<char_type>               traits_type;
sl@0:     typedef typename 
sl@0:             mpl::if_<
sl@0:                 is_convertible<
sl@0:                     base_category,
sl@0:                     input
sl@0:                 >,
sl@0:                 output,
sl@0:                 input
sl@0:             >::type                              mode;
sl@0:     struct category 
sl@0:         : mode, 
sl@0:           filter_tag, 
sl@0:           multichar_tag, 
sl@0:           closable_tag 
sl@0:         { };
sl@0:     explicit inverse( const Filter& filter, 
sl@0:                       std::streamsize buffer_size = 
sl@0:                           default_filter_buffer_size) 
sl@0:         : pimpl_(new impl(filter, buffer_size))
sl@0:         { }
sl@0: 
sl@0:     template<typename Source>
sl@0:     std::streamsize read(Source& src, char* s, std::streamsize n)
sl@0:     {
sl@0:         typedef detail::counted_array_sink<char_type>  array_sink;
sl@0:         typedef composite<filter_ref, array_sink>      filtered_array_sink;
sl@0: 
sl@0:         assert((flags() & f_write) == 0);
sl@0:         if (flags() == 0) {
sl@0:             flags() = f_read;
sl@0:             buf().set(0, 0);
sl@0:         }
sl@0: 
sl@0:         filtered_array_sink snk(filter(), array_sink(s, n));
sl@0:         int_type status;
sl@0:         for ( status = traits_type::good();
sl@0:               snk.second().count() < n && status == traits_type::good(); )
sl@0:         {
sl@0:             status = buf().fill(src);
sl@0:             buf().flush(snk);
sl@0:         }
sl@0:         return snk.second().count() == 0 &&
sl@0:                status == traits_type::eof() 
sl@0:                    ? 
sl@0:                -1
sl@0:                    : 
sl@0:                snk.second().count();
sl@0:     }
sl@0: 
sl@0:     template<typename Sink>
sl@0:     std::streamsize write(Sink& dest, const char* s, std::streamsize n)
sl@0:     {
sl@0:         typedef detail::counted_array_source<char_type>  array_source;
sl@0:         typedef composite<filter_ref, array_source>      filtered_array_source;
sl@0: 
sl@0:         assert((flags() & f_read) == 0);
sl@0:         if (flags() == 0) {
sl@0:             flags() = f_write;
sl@0:             buf().set(0, 0);
sl@0:         }
sl@0:         
sl@0:         filtered_array_source src(filter(), array_source(s, n));
sl@0:         for (bool good = true; src.second().count() < n && good; ) {
sl@0:             buf().fill(src);
sl@0:             good = buf().flush(dest);
sl@0:         }
sl@0:         return src.second().count();
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:         if ((which & BOOST_IOS::out) != 0 && (flags() & f_write) != 0)
sl@0:             buf().flush(dev);
sl@0:         flags() = 0;
sl@0:     }
sl@0: private:
sl@0:     filter_ref filter() { return boost::ref(pimpl_->filter_); }
sl@0:     detail::buffer<char_type>& buf() { return pimpl_->buf_; }
sl@0:     int& flags() { return pimpl_->flags_; }
sl@0:     
sl@0:     enum flags_ {
sl@0:         f_read = 1, f_write = 2
sl@0:     };
sl@0: 
sl@0:     struct impl {
sl@0:         impl(const Filter& filter, std::streamsize n) 
sl@0:             : filter_(filter), buf_(n), flags_(0)
sl@0:         { buf_.set(0, 0); }
sl@0:         Filter                     filter_;
sl@0:         detail::buffer<char_type>  buf_;
sl@0:         int                        flags_;
sl@0:     };
sl@0:     shared_ptr<impl> pimpl_;
sl@0: };
sl@0: 
sl@0: //
sl@0: // Template name: invert.
sl@0: // Template paramters:
sl@0: //      Filter - A model of InputFilter or OutputFilter.
sl@0: // Description: Returns an instance of an appropriate specialization of inverse.
sl@0: //
sl@0: template<typename Filter>
sl@0: inverse<Filter> invert(const Filter& f) { return inverse<Filter>(f); }
sl@0:                     
sl@0: //----------------------------------------------------------------------------//
sl@0: 
sl@0: } } // End namespaces iostreams, boost.
sl@0: 
sl@0: #include <boost/iostreams/detail/config/enable_warnings.hpp>  // MSVC.
sl@0: 
sl@0: #endif // #ifndef BOOST_IOSTREAMS_INVERT_HPP_INCLUDED