| Jeff Thompson | f7d4994 | 2013-08-01 16:47:40 -0700 | [diff] [blame^] | 1 | |
| 2 | #ifndef BOOST_MPL_IF_HPP_INCLUDED |
| 3 | #define BOOST_MPL_IF_HPP_INCLUDED |
| 4 | |
| 5 | // Copyright Aleksey Gurtovoy 2000-2004 |
| 6 | // |
| 7 | // Distributed under the Boost Software License, Version 1.0. |
| 8 | // (See accompanying file LICENSE_1_0.txt or copy at |
| 9 | // http://www.boost.org/LICENSE_1_0.txt) |
| 10 | // |
| 11 | // See http://www.boost.org/libs/mpl for documentation. |
| 12 | |
| 13 | // $Id: if.hpp 49267 2008-10-11 06:19:02Z agurtovoy $ |
| 14 | // $Date: 2008-10-10 23:19:02 -0700 (Fri, 10 Oct 2008) $ |
| 15 | // $Revision: 49267 $ |
| 16 | |
| 17 | #include <boost/mpl/aux_/value_wknd.hpp> |
| 18 | #include <boost/mpl/aux_/static_cast.hpp> |
| 19 | #include <boost/mpl/aux_/na_spec.hpp> |
| 20 | #include <boost/mpl/aux_/lambda_support.hpp> |
| 21 | #include <boost/mpl/aux_/config/integral.hpp> |
| 22 | #include <boost/mpl/aux_/config/ctps.hpp> |
| 23 | #include <boost/mpl/aux_/config/workaround.hpp> |
| 24 | |
| 25 | namespace ndnboost { namespace mpl { |
| 26 | |
| 27 | #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
| 28 | |
| 29 | template< |
| 30 | bool C |
| 31 | , typename T1 |
| 32 | , typename T2 |
| 33 | > |
| 34 | struct if_c |
| 35 | { |
| 36 | typedef T1 type; |
| 37 | }; |
| 38 | |
| 39 | template< |
| 40 | typename T1 |
| 41 | , typename T2 |
| 42 | > |
| 43 | struct if_c<false,T1,T2> |
| 44 | { |
| 45 | typedef T2 type; |
| 46 | }; |
| 47 | |
| 48 | // agurt, 05/sep/04: nondescriptive parameter names for the sake of DigitalMars |
| 49 | // (and possibly MWCW < 8.0); see http://article.gmane.org/gmane.comp.lib.boost.devel/108959 |
| 50 | template< |
| 51 | typename BOOST_MPL_AUX_NA_PARAM(T1) |
| 52 | , typename BOOST_MPL_AUX_NA_PARAM(T2) |
| 53 | , typename BOOST_MPL_AUX_NA_PARAM(T3) |
| 54 | > |
| 55 | struct if_ |
| 56 | { |
| 57 | private: |
| 58 | // agurt, 02/jan/03: two-step 'type' definition for the sake of aCC |
| 59 | typedef if_c< |
| 60 | #if defined(BOOST_MPL_CFG_BCC_INTEGRAL_CONSTANTS) |
| 61 | BOOST_MPL_AUX_VALUE_WKND(T1)::value |
| 62 | #else |
| 63 | BOOST_MPL_AUX_STATIC_CAST(bool, BOOST_MPL_AUX_VALUE_WKND(T1)::value) |
| 64 | #endif |
| 65 | , T2 |
| 66 | , T3 |
| 67 | > almost_type_; |
| 68 | |
| 69 | public: |
| 70 | typedef typename almost_type_::type type; |
| 71 | |
| 72 | BOOST_MPL_AUX_LAMBDA_SUPPORT(3,if_,(T1,T2,T3)) |
| 73 | }; |
| 74 | |
| 75 | #else |
| 76 | |
| 77 | // no partial class template specialization |
| 78 | |
| 79 | namespace aux { |
| 80 | |
| 81 | template< bool C > |
| 82 | struct if_impl |
| 83 | { |
| 84 | template< typename T1, typename T2 > struct result_ |
| 85 | { |
| 86 | typedef T1 type; |
| 87 | }; |
| 88 | }; |
| 89 | |
| 90 | template<> |
| 91 | struct if_impl<false> |
| 92 | { |
| 93 | template< typename T1, typename T2 > struct result_ |
| 94 | { |
| 95 | typedef T2 type; |
| 96 | }; |
| 97 | }; |
| 98 | |
| 99 | } // namespace aux |
| 100 | |
| 101 | template< |
| 102 | bool C_ |
| 103 | , typename T1 |
| 104 | , typename T2 |
| 105 | > |
| 106 | struct if_c |
| 107 | { |
| 108 | typedef typename aux::if_impl< C_ > |
| 109 | ::template result_<T1,T2>::type type; |
| 110 | }; |
| 111 | |
| 112 | // (almost) copy & paste in order to save one more |
| 113 | // recursively nested template instantiation to user |
| 114 | template< |
| 115 | typename BOOST_MPL_AUX_NA_PARAM(C_) |
| 116 | , typename BOOST_MPL_AUX_NA_PARAM(T1) |
| 117 | , typename BOOST_MPL_AUX_NA_PARAM(T2) |
| 118 | > |
| 119 | struct if_ |
| 120 | { |
| 121 | enum { msvc_wknd_ = BOOST_MPL_AUX_MSVC_VALUE_WKND(C_)::value }; |
| 122 | |
| 123 | typedef typename aux::if_impl< BOOST_MPL_AUX_STATIC_CAST(bool, msvc_wknd_) > |
| 124 | ::template result_<T1,T2>::type type; |
| 125 | |
| 126 | BOOST_MPL_AUX_LAMBDA_SUPPORT(3,if_,(C_,T1,T2)) |
| 127 | }; |
| 128 | |
| 129 | #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
| 130 | |
| 131 | BOOST_MPL_AUX_NA_SPEC(3, if_) |
| 132 | |
| 133 | }} |
| 134 | |
| 135 | #endif // BOOST_MPL_IF_HPP_INCLUDED |