projects / ceph.git / blame
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|---|---|---|
| 7c673cae FG |
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 | // Contains the metafunction select, which mimics the effect of a chain of | |
| 9 | // nested mpl if_'s. | |
| 10 | // | |
| 11 | // ----------------------------------------------------------------------------- | |
| 12 | // | |
| 13 | // Usage: | |
| 14 | // | |
| 15 | // typedef typename select< | |
| 16 | // case1, type1, | |
| 17 | // case2, type2, | |
| 18 | // ... | |
| 19 | // true_, typen | |
| 20 | // >::type selection; | |
| 21 | // | |
| 22 | // Here case1, case2, ... are models of MPL::IntegralConstant with value type | |
| 23 | // bool, and n <= 12. | |
| 24 | ||
| 25 | #ifndef BOOST_IOSTREAMS_SELECT_HPP_INCLUDED | |
| 26 | #define BOOST_IOSTREAMS_SELECT_HPP_INCLUDED | |
| 27 | ||
| 28 | #if defined(_MSC_VER) | |
| 29 | # pragma once | |
| 30 | #endif | |
| 31 | ||
| 32 | #include <boost/type_traits/is_base_and_derived.hpp> | |
| 33 | #include <boost/mpl/eval_if.hpp> | |
| 34 | #include <boost/mpl/identity.hpp> | |
| 35 | #include <boost/mpl/if.hpp> | |
| 36 | #include <boost/mpl/void.hpp> | |
| 37 | ||
| 38 | namespace boost { namespace iostreams { | |
| 39 | ||
| 40 | typedef mpl::true_ else_; | |
| 41 | ||
| 42 | template< typename Case1 = mpl::true_, | |
| 43 | typename Type1 = mpl::void_, | |
| 44 | typename Case2 = mpl::true_, | |
| 45 | typename Type2 = mpl::void_, | |
| 46 | typename Case3 = mpl::true_, | |
| 47 | typename Type3 = mpl::void_, | |
| 48 | typename Case4 = mpl::true_, | |
| 49 | typename Type4 = mpl::void_, | |
| 50 | typename Case5 = mpl::true_, | |
| 51 | typename Type5 = mpl::void_, | |
| 52 | typename Case6 = mpl::true_, | |
| 53 | typename Type6 = mpl::void_, | |
| 54 | typename Case7 = mpl::true_, | |
| 55 | typename Type7 = mpl::void_, | |
| 56 | typename Case8 = mpl::true_, | |
| 57 | typename Type8 = mpl::void_, | |
| 58 | typename Case9 = mpl::true_, | |
| 59 | typename Type9 = mpl::void_, | |
| 60 | typename Case10 = mpl::true_, | |
| 61 | typename Type10 = mpl::void_, | |
| 62 | typename Case11 = mpl::true_, | |
| 63 | typename Type11 = mpl::void_, | |
| 64 | typename Case12 = mpl::true_, | |
| 65 | typename Type12 = mpl::void_ > | |
| 66 | struct select { | |
| 67 | typedef typename | |
| 68 | mpl::eval_if< | |
| 69 | Case1, mpl::identity<Type1>, mpl::eval_if< | |
| 70 | Case2, mpl::identity<Type2>, mpl::eval_if< | |
| 71 | Case3, mpl::identity<Type3>, mpl::eval_if< | |
| 72 | Case4, mpl::identity<Type4>, mpl::eval_if< | |
| 73 | Case5, mpl::identity<Type5>, mpl::eval_if< | |
| 74 | Case6, mpl::identity<Type6>, mpl::eval_if< | |
| 75 | Case7, mpl::identity<Type7>, mpl::eval_if< | |
| 76 | Case8, mpl::identity<Type8>, mpl::eval_if< | |
| 77 | Case9, mpl::identity<Type9>, mpl::eval_if< | |
| 78 | Case10, mpl::identity<Type10>, mpl::eval_if< | |
| 79 | Case11, mpl::identity<Type11>, mpl::if_< | |
| 80 | Case12, Type12, mpl::void_ > > > > > > > > > > > | |
| 81 | >::type type; | |
| 82 | }; | |
| 83 | ||
| 84 | } } // End namespaces iostreams, boost. | |
| 85 | ||
| 86 | #endif // #ifndef BOOST_IOSTREAMS_SELECT_HPP_INCLUDED |