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120 lines
3.6 KiB
120 lines
3.6 KiB
// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004 |
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// Use, modification, and distribution is subject to the Boost Software |
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// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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// http://www.boost.org/LICENSE_1_0.txt) |
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// See library home page at http://www.boost.org/libs/numeric/conversion |
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// |
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// Contact the author at: fernando_cacciola@hotmail.com |
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// |
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#ifndef BOOST_NUMERIC_CONVERSION_DETAIL_META_FLC_12NOV2002_HPP |
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#define BOOST_NUMERIC_CONVERSION_DETAIL_META_FLC_12NOV2002_HPP |
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#include "boost/type_traits/remove_cv.hpp" |
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#include "boost/mpl/if.hpp" |
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#include "boost/mpl/eval_if.hpp" |
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#include "boost/mpl/equal_to.hpp" |
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#include "boost/mpl/not.hpp" |
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#include "boost/mpl/and.hpp" |
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#include "boost/mpl/bool.hpp" |
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#include "boost/mpl/identity.hpp" |
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namespace boost { namespace numeric { namespace convdetail |
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{ |
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template< class T1, class T2> |
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struct equal_to |
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{ |
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#if !defined(__BORLANDC__) |
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enum { x = ( BOOST_MPL_AUX_VALUE_WKND(T1)::value == BOOST_MPL_AUX_VALUE_WKND(T2)::value ) }; |
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BOOST_STATIC_CONSTANT(bool, value = x); |
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typedef mpl::bool_<value> type; |
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#else |
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BOOST_STATIC_CONSTANT(bool, value = ( |
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BOOST_MPL_AUX_VALUE_WKND(T1)::value |
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== BOOST_MPL_AUX_VALUE_WKND(T2)::value |
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)); |
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typedef mpl::bool_<( |
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BOOST_MPL_AUX_VALUE_WKND(T1)::value |
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== BOOST_MPL_AUX_VALUE_WKND(T2)::value |
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)> type; |
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#endif |
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}; |
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// Metafunction: |
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// |
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// ct_switch4<Value,Case0Val,Case1Val,Case2Val,Case0Type,Case1Type,Case2Type,DefaultType>::type |
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// |
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// {Value,Case(X)Val} are Integral Constants (such as: mpl::int_<>) |
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// {Case(X)Type,DefaultType} are arbitrary types. (not metafunctions) |
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// |
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// Returns Case(X)Type if Val==Case(X)Val; DefaultType otherwise. |
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// |
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template<class Value, |
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class Case0Val, |
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class Case1Val, |
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class Case2Val, |
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class Case0Type, |
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class Case1Type, |
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class Case2Type, |
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class DefaultType |
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> |
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struct ct_switch4 |
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{ |
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typedef mpl::identity<Case0Type> Case0TypeQ ; |
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typedef mpl::identity<Case1Type> Case1TypeQ ; |
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typedef equal_to<Value,Case0Val> is_case0 ; |
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typedef equal_to<Value,Case1Val> is_case1 ; |
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typedef equal_to<Value,Case2Val> is_case2 ; |
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typedef mpl::if_<is_case2,Case2Type,DefaultType> choose_2_3Q ; |
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typedef mpl::eval_if<is_case1,Case1TypeQ,choose_2_3Q> choose_1_2_3Q ; |
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typedef typename |
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mpl::eval_if<is_case0,Case0TypeQ,choose_1_2_3Q>::type |
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type ; |
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} ; |
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// Metafunction: |
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// |
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// for_both<expr0,expr1,TT,TF,FT,FF>::type |
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// |
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// {exp0,expr1} are Boolean Integral Constants |
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// {TT,TF,FT,FF} are aribtrary types. (not metafunctions) |
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// |
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// According to the combined boolean value of 'expr0 && expr1', selects the corresponding type. |
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// |
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template<class expr0, class expr1, class TT, class TF, class FT, class FF> |
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struct for_both |
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{ |
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typedef mpl::identity<TF> TF_Q ; |
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typedef mpl::identity<TT> TT_Q ; |
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typedef typename mpl::not_<expr0>::type not_expr0 ; |
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typedef typename mpl::not_<expr1>::type not_expr1 ; |
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typedef typename mpl::and_<expr0,expr1>::type caseTT ; |
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typedef typename mpl::and_<expr0,not_expr1>::type caseTF ; |
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typedef typename mpl::and_<not_expr0,expr1>::type caseFT ; |
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typedef mpl::if_<caseFT,FT,FF> choose_FT_FF_Q ; |
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typedef mpl::eval_if<caseTF,TF_Q,choose_FT_FF_Q> choose_TF_FT_FF_Q ; |
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typedef typename mpl::eval_if<caseTT,TT_Q,choose_TF_FT_FF_Q>::type type ; |
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} ; |
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} } } // namespace boost::numeric::convdetail |
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#endif |
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