boost/iostreams/pipeline.hpp

0001 // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
0002 // (C) Copyright 2003-2007 Jonathan Turkanis
0003 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0004 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
0005
0006 // See http://www.boost.org/libs/iostreams for documentation.
0007
0008 #ifndef BOOST_IOSTREAMS_PIPABLE_HPP_INCLUDED
0009 #define BOOST_IOSTREAMS_PIPABLE_HPP_INCLUDED
0010
0011 #if defined(_MSC_VER)
0012 # pragma once
0013 #endif
0014
0015 #include <boost/config.hpp> // BOOST_MSVC.
0016 #include <boost/detail/workaround.hpp>
0017 #include <boost/iostreams/detail/template_params.hpp>
0018 #include <boost/iostreams/traits.hpp>
0019 #include <boost/mpl/bool.hpp>
0020 #include <boost/preprocessor/punctuation/comma_if.hpp>
0021 #include <boost/preprocessor/repetition/enum_params.hpp>
0022 #include <boost/static_assert.hpp>
0023
0024 #define BOOST_IOSTREAMS_PIPABLE(filter, arity) \
0025     template< BOOST_PP_ENUM_PARAMS(arity, typename T) \
0026               BOOST_PP_COMMA_IF(arity) typename Component> \
0027     ::boost::iostreams::pipeline< \
0028         ::boost::iostreams::detail::pipeline_segment< \
0029             filter BOOST_IOSTREAMS_TEMPLATE_ARGS(arity, T) \
0030         >, \
0031         Component \
0032     > operator|( const filter BOOST_IOSTREAMS_TEMPLATE_ARGS(arity, T)& f, \
0033                  const Component& c ) \
0034     { \
0035         typedef ::boost::iostreams::detail::pipeline_segment< \
0036                     filter BOOST_IOSTREAMS_TEMPLATE_ARGS(arity, T) \
0037                 > segment; \
0038         return ::boost::iostreams::pipeline<segment, Component> \
0039                    (segment(f), c); \
0040     } \
0041     /**/
0042
0043 namespace boost { namespace iostreams {
0044
0045 template<typename Pipeline, typename Component>
0046 struct pipeline;
0047
0048 namespace detail {
0049
0050 #if BOOST_WORKAROUND(BOOST_BORLANDC, < 0x600)
0051     template<typename T>
0052     struct is_pipeline : mpl::false_ { };
0053
0054     template<typename Pipeline, typename Component>
0055     struct is_pipeline< pipeline<Pipeline, Component> > : mpl::true_ { };
0056 #endif
0057
0058 template<typename Component>
0059 class pipeline_segment
0060 {
0061 public:
0062     pipeline_segment(const Component& component)
0063         : component_(component)
0064         { }
0065     template<typename Fn>
0066     void for_each(Fn fn) const { fn(component_); }
0067     template<typename Chain>
0068     void push(Chain& chn) const { chn.push(component_); }
0069 private:
0070     pipeline_segment operator=(const pipeline_segment&);
0071     const Component& component_;
0072 };
0073
0074 } // End namespace detail.
0075
0076 //------------------Definition of Pipeline------------------------------------//
0077
0078 template<typename Pipeline, typename Component>
0079 struct pipeline : Pipeline {
0080     typedef Pipeline   pipeline_type;
0081     typedef Component  component_type;
0082     pipeline(const Pipeline& p, const Component& component)
0083         : Pipeline(p), component_(component)
0084         { }
0085     template<typename Fn>
0086     void for_each(Fn fn) const
0087     {
0088         Pipeline::for_each(fn);
0089         fn(component_);
0090     }
0091     template<typename Chain>
0092     void push(Chain& chn) const
0093     {
0094         Pipeline::push(chn);
0095         chn.push(component_);
0096     }
0097     const Pipeline& tail() const { return *this; }
0098     const Component& head() const { return component_; }
0099 private:
0100     pipeline operator=(const pipeline&);
0101     const Component& component_;
0102 };
0103
0104 template<typename Pipeline, typename Filter, typename Component>
0105 pipeline<pipeline<Pipeline, Filter>, Component>
0106 operator|(const pipeline<Pipeline, Filter>& p, const Component& cmp)
0107 {
0108     BOOST_STATIC_ASSERT(is_filter<Filter>::value);
0109     return pipeline<pipeline<Pipeline, Filter>, Component>(p, cmp);
0110 }
0111
0112 } } // End namespaces iostreams, boost.
0113
0114 #endif // #ifndef BOOST_IOSTREAMS_PIPABLE_HPP_INCLUDED