// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004 // Use, modification, and distribution is subject to 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 library home page at http://www.boost.org/libs/numeric/conversion // // Contact the author at: fernando_cacciola@hotmail.com // #ifndef BOOST_NUMERIC_CONVERSION_DETAIL_META_FLC_12NOV2002_HPP #define BOOST_NUMERIC_CONVERSION_DETAIL_META_FLC_12NOV2002_HPP #include "boost/type_traits/remove_cv.hpp" #include "boost/mpl/if.hpp" #include "boost/mpl/eval_if.hpp" #include "boost/mpl/equal_to.hpp" #include "boost/mpl/not.hpp" #include "boost/mpl/and.hpp" #include "boost/mpl/bool.hpp" #include "boost/mpl/identity.hpp" namespace boost { namespace numeric { namespace convdetail { template< class T1, class T2> struct equal_to { #if !defined(__BORLANDC__) enum { x = ( BOOST_MPL_AUX_VALUE_WKND(T1)::value == BOOST_MPL_AUX_VALUE_WKND(T2)::value ) }; BOOST_STATIC_CONSTANT(bool, value = x); typedef mpl::bool_<value> type; #else BOOST_STATIC_CONSTANT(bool, value = ( BOOST_MPL_AUX_VALUE_WKND(T1)::value == BOOST_MPL_AUX_VALUE_WKND(T2)::value )); typedef mpl::bool_<( BOOST_MPL_AUX_VALUE_WKND(T1)::value == BOOST_MPL_AUX_VALUE_WKND(T2)::value )> type; #endif }; // Metafunction: // // ct_switch4<Value,Case0Val,Case1Val,Case2Val,Case0Type,Case1Type,Case2Type,DefaultType>::type // // {Value,Case(X)Val} are Integral Constants (such as: mpl::int_<>) // {Case(X)Type,DefaultType} are arbitrary types. (not metafunctions) // // Returns Case(X)Type if Val==Case(X)Val; DefaultType otherwise. // template<class Value, class Case0Val, class Case1Val, class Case2Val, class Case0Type, class Case1Type, class Case2Type, class DefaultType > struct ct_switch4 { typedef mpl::identity<Case0Type> Case0TypeQ ; typedef mpl::identity<Case1Type> Case1TypeQ ; typedef equal_to<Value,Case0Val> is_case0 ; typedef equal_to<Value,Case1Val> is_case1 ; typedef equal_to<Value,Case2Val> is_case2 ; typedef mpl::if_<is_case2,Case2Type,DefaultType> choose_2_3Q ; typedef mpl::eval_if<is_case1,Case1TypeQ,choose_2_3Q> choose_1_2_3Q ; typedef typename mpl::eval_if<is_case0,Case0TypeQ,choose_1_2_3Q>::type type ; } ; // Metafunction: // // for_both<expr0,expr1,TT,TF,FT,FF>::type // // {exp0,expr1} are Boolean Integral Constants // {TT,TF,FT,FF} are aribtrary types. (not metafunctions) // // According to the combined boolean value of 'expr0 && expr1', selects the corresponding type. // template<class expr0, class expr1, class TT, class TF, class FT, class FF> struct for_both { typedef mpl::identity<TF> TF_Q ; typedef mpl::identity<TT> TT_Q ; typedef typename mpl::not_<expr0>::type not_expr0 ; typedef typename mpl::not_<expr1>::type not_expr1 ; typedef typename mpl::and_<expr0,expr1>::type caseTT ; typedef typename mpl::and_<expr0,not_expr1>::type caseTF ; typedef typename mpl::and_<not_expr0,expr1>::type caseFT ; typedef mpl::if_<caseFT,FT,FF> choose_FT_FF_Q ; typedef mpl::eval_if<caseTF,TF_Q,choose_FT_FF_Q> choose_TF_FT_FF_Q ; typedef typename mpl::eval_if<caseTT,TT_Q,choose_TF_FT_FF_Q>::type type ; } ; } } } // namespace boost::numeric::convdetail #endif