1 // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) 2 // (C) Copyright 2003-2007 Jonathan Turkanis 3 // Distributed under the Boost Software License, Version 1.0. (See accompanying 4 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) 5 6 // See http://www.boost.org/libs/iostreams for documentation. 7 8 #ifndef BOOST_IOSTREAMS_DETAIL_BOOL_TRAIT_DEF_HPP_INCLUDED 9 #define BOOST_IOSTREAMS_DETAIL_BOOL_TRAIT_DEF_HPP_INCLUDED 10 11 #include <boost/config.hpp> // BOOST_STATIC_CONSTANT. 12 #include <boost/iostreams/detail/template_params.hpp> 13 #include <boost/mpl/aux_/lambda_support.hpp> 14 #include <boost/mpl/bool.hpp> 15 #include <boost/preprocessor/cat.hpp> 16 #include <boost/preprocessor/repetition/enum_params.hpp> 17 #include <boost/type_traits/detail/yes_no_type.hpp> 18 19 // 20 // Macro name: BOOST_IOSTREAMS_BOOL_TRAIT_DEF 21 // Description: Used to generate the traits classes is_istream, is_ostream, 22 // etc. 23 // 24 #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x582)) 25 # define BOOST_IOSTREAMS_TRAIT_NAMESPACE(trait) 26 #else 27 # define BOOST_IOSTREAMS_TRAIT_NAMESPACE(trait) BOOST_PP_CAT(trait, _impl_):: 28 #endif 29 #define BOOST_IOSTREAMS_BOOL_TRAIT_DEF(trait, type, arity) \ 30 namespace BOOST_PP_CAT(trait, _impl_) { \ 31 BOOST_IOSTREAMS_TEMPLATE_PARAMS(arity, T) \ 32 type_traits::yes_type helper \ 33 (const volatile type BOOST_IOSTREAMS_TEMPLATE_ARGS(arity, T)*); \ 34 type_traits::no_type helper(...); \ 35 template<typename T> \ 36 struct impl { \ 37 BOOST_STATIC_CONSTANT(bool, value = \ 38 (sizeof(BOOST_IOSTREAMS_TRAIT_NAMESPACE(trait) \ 39 helper(static_cast<T*>(0))) == \ 40 sizeof(type_traits::yes_type))); \ 41 }; \ 42 } \ 43 template<typename T> \ 44 struct trait \ 45 : mpl::bool_<BOOST_PP_CAT(trait, _impl_)::impl<T>::value> \ 46 { BOOST_MPL_AUX_LAMBDA_SUPPORT(1, trait, (T)) }; \ 47 /**/ 48 49 #endif // #ifndef BOOST_IOSTREAMS_DETAIL_BOOL_TRAIT_DEF_HPP_INCLUDED 50