// (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 | |