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: // 
sl@0: // Contains metafunctions char_type_of, category_of and mode_of used for
sl@0: // deducing the i/o category and i/o mode of a model of Filter or Device.
sl@0: //
sl@0: // Also contains several utility metafunctions, functions and macros.
sl@0: //
sl@0: 
sl@0: #ifndef BOOST_IOSTREAMS_IO_TRAITS_HPP_INCLUDED
sl@0: #define BOOST_IOSTREAMS_IO_TRAITS_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 <iosfwd>            // stream types, char_traits.
sl@0: #include <boost/config.hpp>  // partial spec, deduced typename.
sl@0: #include <boost/iostreams/categories.hpp>
sl@0: #include <boost/iostreams/detail/bool_trait_def.hpp> 
sl@0: #include <boost/iostreams/detail/config/wide_streams.hpp>
sl@0: #include <boost/iostreams/detail/is_iterator_range.hpp>    
sl@0: #include <boost/iostreams/detail/select.hpp>        
sl@0: #include <boost/iostreams/detail/select_by_size.hpp>      
sl@0: #include <boost/iostreams/detail/wrap_unwrap.hpp>       
sl@0: #include <boost/iostreams/traits_fwd.hpp> 
sl@0: #include <boost/mpl/bool.hpp>   
sl@0: #include <boost/mpl/eval_if.hpp>
sl@0: #include <boost/mpl/identity.hpp>      
sl@0: #include <boost/mpl/int.hpp>  
sl@0: #include <boost/mpl/or.hpp>                         
sl@0: #include <boost/range/iterator_range.hpp>
sl@0: #include <boost/range/value_type.hpp>
sl@0: #include <boost/type_traits/is_convertible.hpp>     
sl@0: 
sl@0: namespace boost { namespace iostreams {        
sl@0: 
sl@0: //------------------Definitions of predicates for streams and stream buffers--//
sl@0: 
sl@0: #ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //--------------------------------//
sl@0: 
sl@0: BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_istream, std::basic_istream, 2)
sl@0: BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_ostream, std::basic_ostream, 2)
sl@0: BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_iostream, std::basic_iostream, 2)
sl@0: BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_streambuf, std::basic_streambuf, 2)
sl@0: BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_stringstream, std::basic_stringstream, 3)
sl@0: BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_stringbuf, std::basic_stringbuf, 3)
sl@0: 
sl@0: #else // #ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //-----------------------//
sl@0: 
sl@0: BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_istream, std::istream, 0)
sl@0: BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_ostream, std::ostream, 0)
sl@0: BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_iostream, std::iostream, 0)
sl@0: BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_streambuf, std::streambuf, 0)
sl@0: 
sl@0: #endif // #ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //----------------------//
sl@0: 
sl@0: template<typename T>
sl@0: struct is_std_io
sl@0:     : mpl::or_< is_istream<T>, is_ostream<T>, is_streambuf<T> >
sl@0:     { };
sl@0: 
sl@0: namespace detail {
sl@0: 
sl@0: template<typename T, typename Tr>
sl@0: class linked_streambuf;
sl@0: 
sl@0: BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_linked, linked_streambuf, 2)
sl@0: 
sl@0: } // End namespace detail.
sl@0:                     
sl@0: //------------------Definitions of char_type_of-------------------------------//
sl@0: 
sl@0: namespace detail {
sl@0: 
sl@0: template<typename T>
sl@0: struct member_char_type { typedef typename T::char_type type; };
sl@0: 
sl@0: } // End namespace detail.
sl@0: 
sl@0: #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION //---------------------------//
sl@0: # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //-------------------------------//
sl@0: 
sl@0: template<typename T>
sl@0: struct char_type_of 
sl@0:     : detail::member_char_type<
sl@0:           typename detail::unwrapped_type<T>::type
sl@0:       > 
sl@0:     { };
sl@0: 
sl@0: # else // # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //---------------------//
sl@0: 
sl@0: template<typename T>
sl@0: struct char_type_of {
sl@0:     typedef typename detail::unwrapped_type<T>::type U;
sl@0:     typedef typename 
sl@0:             mpl::eval_if<
sl@0:                 is_std_io<U>,
sl@0:                 mpl::identity<char>,
sl@0:                 detail::member_char_type<U>
sl@0:             >::type type;
sl@0: };
sl@0: 
sl@0: # endif // # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //--------------------//
sl@0: 
sl@0: template<typename Iter>
sl@0: struct char_type_of< iterator_range<Iter> > {
sl@0:     typedef typename iterator_value<Iter>::type type;
sl@0: };
sl@0: 
sl@0: #else // #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION //------------------//
sl@0: 
sl@0: template<typename T>
sl@0: struct char_type_of {
sl@0:     template<typename U>
sl@0:     struct get_value_type {
sl@0:         typedef typename range_value<U>::type type;
sl@0:     };
sl@0:     typedef typename 
sl@0:             mpl::eval_if<
sl@0:                 is_iterator_range<T>,
sl@0:                 get_value_type<T>,
sl@0:                 detail::member_char_type<
sl@0:                     BOOST_DEDUCED_TYPENAME detail::unwrapped_type<T>::type
sl@0:                 >
sl@0:             >::type type;
sl@0: };
sl@0: 
sl@0: #endif // #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION //-----------------//
sl@0: 
sl@0: //------------------Definitions of category_of--------------------------------//
sl@0: 
sl@0: namespace detail {
sl@0: 
sl@0: template<typename T>
sl@0: struct member_category { typedef typename T::category type; };
sl@0: 
sl@0: } // End namespace detail.
sl@0: 
sl@0: template<typename T>
sl@0: struct category_of {
sl@0:     template<typename U>
sl@0:     struct member_category { 
sl@0:         typedef typename U::category type; 
sl@0:     };
sl@0:     typedef typename detail::unwrapped_type<T>::type U;
sl@0:     typedef typename  
sl@0:             mpl::eval_if<
sl@0:                 is_std_io<U>,
sl@0:                 iostreams::select<  // Disambiguation for Tru64
sl@0:                     is_iostream<U>,   iostream_tag, 
sl@0:                     is_istream<U>,    istream_tag, 
sl@0:                     is_ostream<U>,    ostream_tag,
sl@0:                     is_streambuf<U>,  streambuf_tag
sl@0:                 >,
sl@0:                 detail::member_category<U>
sl@0:             >::type type;      
sl@0: };
sl@0: 
sl@0: //------------------Definition of get_category--------------------------------//
sl@0: 
sl@0: // 
sl@0: // Returns an object of type category_of<T>::type.
sl@0: // 
sl@0: template<typename T>
sl@0: inline typename category_of<T>::type get_category(const T&) 
sl@0: { typedef typename category_of<T>::type category; return category(); }
sl@0: 
sl@0: //------------------Definition of int_type_of---------------------------------//
sl@0: 
sl@0: template<typename T>
sl@0: struct int_type_of { 
sl@0: #ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES
sl@0:     typedef std::char_traits<
sl@0:                 BOOST_DEDUCED_TYPENAME char_type_of<T>::type
sl@0:             > traits_type;      
sl@0:     typedef typename traits_type::int_type type; 
sl@0: #else  
sl@0:     typedef int                            type; 
sl@0: #endif
sl@0: };
sl@0: 
sl@0: //------------------Definition of mode----------------------------------------//
sl@0: 
sl@0: namespace detail {
sl@0: 
sl@0: template<int N> struct io_mode_impl;
sl@0: 
sl@0: #define BOOST_IOSTREAMS_MODE_HELPER(tag_, id_) \
sl@0:     case_<id_> io_mode_impl_helper(tag_); \
sl@0:     template<> struct io_mode_impl<id_> { typedef tag_ type; }; \
sl@0:     /**/
sl@0: BOOST_IOSTREAMS_MODE_HELPER(input, 1)
sl@0: BOOST_IOSTREAMS_MODE_HELPER(output, 2)
sl@0: BOOST_IOSTREAMS_MODE_HELPER(bidirectional, 3)
sl@0: BOOST_IOSTREAMS_MODE_HELPER(input_seekable, 4)
sl@0: BOOST_IOSTREAMS_MODE_HELPER(output_seekable, 5)
sl@0: BOOST_IOSTREAMS_MODE_HELPER(seekable, 6)
sl@0: BOOST_IOSTREAMS_MODE_HELPER(dual_seekable, 7)
sl@0: BOOST_IOSTREAMS_MODE_HELPER(bidirectional_seekable, 8)
sl@0: BOOST_IOSTREAMS_MODE_HELPER(dual_use, 9)
sl@0: #undef BOOST_IOSTREAMS_MODE_HELPER
sl@0: 
sl@0: template<typename T>
sl@0: struct io_mode_id {
sl@0:     typedef typename category_of<T>::type category;
sl@0:     BOOST_SELECT_BY_SIZE(int, value, detail::io_mode_impl_helper(category()));
sl@0: };
sl@0: 
sl@0: } // End namespace detail.
sl@0: 
sl@0: template<typename T> // Borland 5.6.4 requires this circumlocution.
sl@0: struct mode_of : detail::io_mode_impl< detail::io_mode_id<T>::value > { };
sl@0:                     
sl@0: //------------------Definition of is_device, is_filter and is_direct----------//
sl@0: 
sl@0: namespace detail {
sl@0: 
sl@0: template<typename T, typename Tag>
sl@0: struct has_trait_impl {
sl@0:     typedef typename category_of<T>::type category;
sl@0:     BOOST_STATIC_CONSTANT(bool, value = (is_convertible<category, Tag>::value));
sl@0: };
sl@0: 
sl@0: template<typename T, typename Tag>
sl@0: struct has_trait 
sl@0:     : mpl::bool_<has_trait_impl<T, Tag>::value>
sl@0:     { }; 
sl@0: 
sl@0: } // End namespace detail.
sl@0: 
sl@0: template<typename T>
sl@0: struct is_device : detail::has_trait<T, device_tag> { };
sl@0: 
sl@0: template<typename T>
sl@0: struct is_filter : detail::has_trait<T, filter_tag> { };
sl@0: 
sl@0: template<typename T>
sl@0: struct is_direct : detail::has_trait<T, direct_tag> { };
sl@0:                     
sl@0: //------------------Definition of BOOST_IOSTREAMS_STREAMBUF_TYPEDEFS----------//
sl@0: 
sl@0: #define BOOST_IOSTREAMS_STREAMBUF_TYPEDEFS(Tr) \
sl@0:     typedef Tr                              traits_type; \
sl@0:     typedef typename traits_type::int_type  int_type; \
sl@0:     typedef typename traits_type::off_type  off_type; \
sl@0:     typedef typename traits_type::pos_type  pos_type; \
sl@0:     /**/
sl@0: 
sl@0: } } // End namespaces iostreams, boost.
sl@0: 
sl@0: #endif // #ifndef BOOST_IOSTREAMS_IO_TRAITS_HPP_INCLUDED