//  © 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





