//---------------------------------------------------------------------------// // Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@gmail.com> // // Distributed under the Boost Software License, Version 1.0 // See accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt // // See http://boostorg.github.com/compute for more information. //---------------------------------------------------------------------------// #ifndef BOOST_COMPUTE_FUNCTIONAL_GET_HPP #define BOOST_COMPUTE_FUNCTIONAL_GET_HPP #include <cstddef> #include <boost/compute/types/fundamental.hpp> #include <boost/compute/type_traits/scalar_type.hpp> namespace boost { namespace compute { namespace detail { // meta-function returning the result type for get<N>() template<size_t N, class Arg> struct get_result_type { typedef typename scalar_type<Arg>::type type; }; template<size_t N, class Arg, class T> struct invoked_get { typedef typename get_result_type<N, T>::type result_type; invoked_get(const Arg &arg) : m_arg(arg) { } Arg m_arg; }; } // end detail namespace /// Returns the \c N'th element of an aggregate type (e.g. scalarN, /// pair, tuple, etc.). /// /// \see \ref field "field<T>" template<size_t N> struct get { /// \internal_ template<class> struct result; /// \internal_ template<class F, class Arg> struct result<F(Arg)> { typedef typename detail::get_result_type<N, Arg>::type type; }; template<class Arg> detail::invoked_get< N, Arg, typename boost::remove_cv<typename Arg::result_type>::type > operator()(const Arg &arg) const { typedef typename boost::remove_cv<typename Arg::result_type>::type T; return detail::invoked_get<N, Arg, T>(arg); } }; } // end compute namespace } // end boost namespace #endif // BOOST_COMPUTE_FUNCTIONAL_GET_HPP