Chris@16: // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
Chris@16: // (C) Copyright 2003-2007 Jonathan Turkanis
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
Chris@16: 
Chris@16: // See http://www.boost.org/libs/iostreams for documentation.
Chris@16: 
Chris@16: #ifndef BOOST_IOSTREAMS_INVERT_HPP_INCLUDED
Chris@16: #define BOOST_IOSTREAMS_INVERT_HPP_INCLUDED
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
Chris@16: # pragma once
Chris@16: #endif              
Chris@16: 
Chris@16: #include <algorithm>                             // copy, min.  
Chris@16: #include <boost/assert.hpp>
Chris@16: #include <boost/config.hpp>                      // BOOST_DEDUCED_TYPENAME.       
Chris@16: #include <boost/detail/workaround.hpp>           // default_filter_buffer_size.
Chris@16: #include <boost/iostreams/char_traits.hpp>
Chris@16: #include <boost/iostreams/compose.hpp>
Chris@16: #include <boost/iostreams/constants.hpp>
Chris@16: #include <boost/iostreams/device/array.hpp>
Chris@16: #include <boost/iostreams/detail/buffer.hpp>
Chris@16: #include <boost/iostreams/detail/counted_array.hpp>
Chris@16: #include <boost/iostreams/detail/execute.hpp>
Chris@16: #include <boost/iostreams/detail/functional.hpp> // clear_flags, call_reset
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/ref.hpp>
Chris@16: #include <boost/shared_ptr.hpp>
Chris@16: #include <boost/type_traits/is_convertible.hpp>
Chris@16: 
Chris@16: // Must come last.
Chris@16: #include <boost/iostreams/detail/config/disable_warnings.hpp>  // MSVC.
Chris@16: 
Chris@16: namespace boost { namespace iostreams {
Chris@16: 
Chris@16: //
Chris@16: // Template name: inverse.
Chris@16: // Template parameters:
Chris@16: //      Filter - A model of InputFilter or OutputFilter.
Chris@16: // Description: Generates an InputFilter from an OutputFilter or
Chris@16: //      vice versa.
Chris@16: //
Chris@16: template<typename Filter>
Chris@16: class inverse {
Chris@16: private:
Chris@16:     BOOST_STATIC_ASSERT(is_filter<Filter>::value);
Chris@16:     typedef typename category_of<Filter>::type   base_category;
Chris@16:     typedef reference_wrapper<Filter>            filter_ref;
Chris@16: public:
Chris@16:     typedef typename char_type_of<Filter>::type  char_type;
Chris@16:     typedef typename int_type_of<Filter>::type   int_type;
Chris@16:     typedef char_traits<char_type>               traits_type;
Chris@16:     typedef typename 
Chris@16:             mpl::if_<
Chris@16:                 is_convertible<
Chris@16:                     base_category,
Chris@16:                     input
Chris@16:                 >,
Chris@16:                 output,
Chris@16:                 input
Chris@16:             >::type                              mode;
Chris@16:     struct category 
Chris@16:         : mode, 
Chris@16:           filter_tag, 
Chris@16:           multichar_tag, 
Chris@16:           closable_tag 
Chris@16:         { };
Chris@16:     explicit inverse( const Filter& filter, 
Chris@16:                       std::streamsize buffer_size = 
Chris@16:                           default_filter_buffer_size) 
Chris@16:         : pimpl_(new impl(filter, buffer_size))
Chris@16:         { }
Chris@16: 
Chris@16:     template<typename Source>
Chris@16:     std::streamsize read(Source& src, char* s, std::streamsize n)
Chris@16:     {
Chris@16:         typedef detail::counted_array_sink<char_type>  array_sink;
Chris@16:         typedef composite<filter_ref, array_sink>      filtered_array_sink;
Chris@16: 
Chris@16:         BOOST_ASSERT((flags() & f_write) == 0);
Chris@16:         if (flags() == 0) {
Chris@16:             flags() = f_read;
Chris@16:             buf().set(0, 0);
Chris@16:         }
Chris@16: 
Chris@16:         filtered_array_sink snk(filter(), array_sink(s, n));
Chris@16:         int_type status;
Chris@16:         for ( status = traits_type::good();
Chris@16:               snk.second().count() < n && status == traits_type::good(); )
Chris@16:         {
Chris@16:             status = buf().fill(src);
Chris@16:             buf().flush(snk);
Chris@16:         }
Chris@16:         return snk.second().count() == 0 &&
Chris@16:                status == traits_type::eof() 
Chris@16:                    ? 
Chris@16:                -1
Chris@16:                    : 
Chris@16:                snk.second().count();
Chris@16:     }
Chris@16: 
Chris@16:     template<typename Sink>
Chris@16:     std::streamsize write(Sink& dest, const char* s, std::streamsize n)
Chris@16:     {
Chris@16:         typedef detail::counted_array_source<char_type>  array_source;
Chris@16:         typedef composite<filter_ref, array_source>      filtered_array_source;
Chris@16: 
Chris@16:         BOOST_ASSERT((flags() & f_read) == 0);
Chris@16:         if (flags() == 0) {
Chris@16:             flags() = f_write;
Chris@16:             buf().set(0, 0);
Chris@16:         }
Chris@16:         
Chris@16:         filtered_array_source src(filter(), array_source(s, n));
Chris@16:         for (bool good = true; src.second().count() < n && good; ) {
Chris@16:             buf().fill(src);
Chris@16:             good = buf().flush(dest);
Chris@16:         }
Chris@16:         return src.second().count();
Chris@16:     }
Chris@16: 
Chris@16:     template<typename Device>
Chris@16:     void close(Device& dev)
Chris@16:     {
Chris@16:         detail::execute_all(
Chris@16:             detail::flush_buffer(buf(), dev, (flags() & f_write) != 0),
Chris@16:             detail::call_close_all(pimpl_->filter_, dev),
Chris@16:             detail::clear_flags(flags())
Chris@16:         );
Chris@16:     }
Chris@16: private:
Chris@16:     filter_ref filter() { return boost::ref(pimpl_->filter_); }
Chris@16:     detail::buffer<char_type>& buf() { return pimpl_->buf_; }
Chris@16:     int& flags() { return pimpl_->flags_; }
Chris@16:     
Chris@16:     enum flags_ {
Chris@16:         f_read = 1, f_write = 2
Chris@16:     };
Chris@16: 
Chris@16:     struct impl {
Chris@16:         impl(const Filter& filter, std::streamsize n) 
Chris@16:             : filter_(filter), buf_(n), flags_(0)
Chris@16:         { buf_.set(0, 0); }
Chris@16:         Filter                     filter_;
Chris@16:         detail::buffer<char_type>  buf_;
Chris@16:         int                        flags_;
Chris@16:     };
Chris@16:     shared_ptr<impl> pimpl_;
Chris@16: };
Chris@16: 
Chris@16: //
Chris@16: // Template name: invert.
Chris@16: // Template parameters:
Chris@16: //      Filter - A model of InputFilter or OutputFilter.
Chris@16: // Description: Returns an instance of an appropriate specialization of inverse.
Chris@16: //
Chris@16: template<typename Filter>
Chris@16: inverse<Filter> invert(const Filter& f) { return inverse<Filter>(f); }
Chris@16:                     
Chris@16: //----------------------------------------------------------------------------//
Chris@16: 
Chris@16: } } // End namespaces iostreams, boost.
Chris@16: 
Chris@16: #include <boost/iostreams/detail/config/enable_warnings.hpp>  // MSVC.
Chris@16: 
Chris@16: #endif // #ifndef BOOST_IOSTREAMS_INVERT_HPP_INCLUDED