| // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) | |
| // (C) Copyright 2003-2007 Jonathan Turkanis | |
| // 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://www.boost.org/libs/iostreams for documentation. | |
| // Contains the metafunction select, which mimics the effect of a chain of | |
| // nested mpl if_'s. | |
| // | |
| // ----------------------------------------------------------------------------- | |
| // | |
| // Usage: | |
| // | |
| // typedef typename select< | |
| // case1, type1, | |
| // case2, type2, | |
| // ... | |
| // true_, typen | |
| // >::type selection; | |
| // | |
| // Here case1, case2, ... are models of MPL::IntegralConstant with value type | |
| // bool, and n <= 12. | |
| #ifndef BOOST_IOSTREAMS_SELECT_HPP_INCLUDED | |
| #define BOOST_IOSTREAMS_SELECT_HPP_INCLUDED | |
| #if defined(_MSC_VER) && (_MSC_VER >= 1020) | |
| # pragma once | |
| #endif | |
| #include <boost/type_traits/is_base_and_derived.hpp> | |
| #include <boost/mpl/eval_if.hpp> | |
| #include <boost/mpl/identity.hpp> | |
| #include <boost/mpl/if.hpp> | |
| #include <boost/mpl/void.hpp> | |
| namespace boost { namespace iostreams { | |
| typedef mpl::true_ else_; | |
| template< typename Case1 = mpl::true_, | |
| typename Type1 = mpl::void_, | |
| typename Case2 = mpl::true_, | |
| typename Type2 = mpl::void_, | |
| typename Case3 = mpl::true_, | |
| typename Type3 = mpl::void_, | |
| typename Case4 = mpl::true_, | |
| typename Type4 = mpl::void_, | |
| typename Case5 = mpl::true_, | |
| typename Type5 = mpl::void_, | |
| typename Case6 = mpl::true_, | |
| typename Type6 = mpl::void_, | |
| typename Case7 = mpl::true_, | |
| typename Type7 = mpl::void_, | |
| typename Case8 = mpl::true_, | |
| typename Type8 = mpl::void_, | |
| typename Case9 = mpl::true_, | |
| typename Type9 = mpl::void_, | |
| typename Case10 = mpl::true_, | |
| typename Type10 = mpl::void_, | |
| typename Case11 = mpl::true_, | |
| typename Type11 = mpl::void_, | |
| typename Case12 = mpl::true_, | |
| typename Type12 = mpl::void_ > | |
| struct select { | |
| typedef typename | |
| mpl::eval_if< | |
| Case1, mpl::identity<Type1>, mpl::eval_if< | |
| Case2, mpl::identity<Type2>, mpl::eval_if< | |
| Case3, mpl::identity<Type3>, mpl::eval_if< | |
| Case4, mpl::identity<Type4>, mpl::eval_if< | |
| Case5, mpl::identity<Type5>, mpl::eval_if< | |
| Case6, mpl::identity<Type6>, mpl::eval_if< | |
| Case7, mpl::identity<Type7>, mpl::eval_if< | |
| Case8, mpl::identity<Type8>, mpl::eval_if< | |
| Case9, mpl::identity<Type9>, mpl::eval_if< | |
| Case10, mpl::identity<Type10>, mpl::eval_if< | |
| Case11, mpl::identity<Type11>, mpl::if_< | |
| Case12, Type12, mpl::void_ > > > > > > > > > > > | |
| >::type type; | |
| }; | |
| } } // End namespaces iostreams, boost. | |
| #endif // #ifndef BOOST_IOSTREAMS_SELECT_HPP_INCLUDED |