1 // © Copyright Fernando Luis Cacciola Carballal 2000-2004
2 // Use, modification, and distribution is subject to the Boost Software
3 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
4 // http://www.boost.org/LICENSE_1_0.txt)
6 // See library home page at http://www.boost.org/libs/numeric/conversion
8 // Contact the author at: fernando_cacciola@hotmail.com
10 #ifndef BOOST_NUMERIC_CONVERSION_DETAIL_META_FLC_12NOV2002_HPP
11 #define BOOST_NUMERIC_CONVERSION_DETAIL_META_FLC_12NOV2002_HPP
13 #include "boost/type_traits/remove_cv.hpp"
15 #include "boost/mpl/if.hpp"
16 #include "boost/mpl/eval_if.hpp"
17 #include "boost/mpl/equal_to.hpp"
18 #include "boost/mpl/not.hpp"
19 #include "boost/mpl/and.hpp"
20 #include "boost/mpl/bool.hpp"
21 #include "boost/mpl/identity.hpp"
23 namespace boost { namespace numeric { namespace convdetail
25 template< class T1, class T2>
28 #if !defined(__BORLANDC__)
30 enum { x = ( BOOST_MPL_AUX_VALUE_WKND(T1)::value == BOOST_MPL_AUX_VALUE_WKND(T2)::value ) };
32 BOOST_STATIC_CONSTANT(bool, value = x);
34 typedef mpl::bool_<value> type;
38 BOOST_STATIC_CONSTANT(bool, value = (
39 BOOST_MPL_AUX_VALUE_WKND(T1)::value
40 == BOOST_MPL_AUX_VALUE_WKND(T2)::value
44 BOOST_MPL_AUX_VALUE_WKND(T1)::value
45 == BOOST_MPL_AUX_VALUE_WKND(T2)::value
52 // ct_switch4<Value,Case0Val,Case1Val,Case2Val,Case0Type,Case1Type,Case2Type,DefaultType>::type
54 // {Value,Case(X)Val} are Integral Constants (such as: mpl::int_<>)
55 // {Case(X)Type,DefaultType} are arbitrary types. (not metafunctions)
57 // Returns Case(X)Type if Val==Case(X)Val; DefaultType otherwise.
70 typedef mpl::identity<Case0Type> Case0TypeQ ;
71 typedef mpl::identity<Case1Type> Case1TypeQ ;
73 typedef equal_to<Value,Case0Val> is_case0 ;
74 typedef equal_to<Value,Case1Val> is_case1 ;
75 typedef equal_to<Value,Case2Val> is_case2 ;
77 typedef mpl::if_<is_case2,Case2Type,DefaultType> choose_2_3Q ;
78 typedef mpl::eval_if<is_case1,Case1TypeQ,choose_2_3Q> choose_1_2_3Q ;
81 mpl::eval_if<is_case0,Case0TypeQ,choose_1_2_3Q>::type
90 // for_both<expr0,expr1,TT,TF,FT,FF>::type
92 // {exp0,expr1} are Boolean Integral Constants
93 // {TT,TF,FT,FF} are aribtrary types. (not metafunctions)
95 // According to the combined boolean value of 'expr0 && expr1', selects the corresponding type.
97 template<class expr0, class expr1, class TT, class TF, class FT, class FF>
100 typedef mpl::identity<TF> TF_Q ;
101 typedef mpl::identity<TT> TT_Q ;
103 typedef typename mpl::not_<expr0>::type not_expr0 ;
104 typedef typename mpl::not_<expr1>::type not_expr1 ;
106 typedef typename mpl::and_<expr0,expr1>::type caseTT ;
107 typedef typename mpl::and_<expr0,not_expr1>::type caseTF ;
108 typedef typename mpl::and_<not_expr0,expr1>::type caseFT ;
110 typedef mpl::if_<caseFT,FT,FF> choose_FT_FF_Q ;
111 typedef mpl::eval_if<caseTF,TF_Q,choose_FT_FF_Q> choose_TF_FT_FF_Q ;
113 typedef typename mpl::eval_if<caseTT,TT_Q,choose_TF_FT_FF_Q>::type type ;
116 } } } // namespace boost::numeric::convdetail