//  © 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