epoc32/include/stdapis/boost/numeric/conversion/detail/meta.hpp
author William Roberts <williamr@symbian.org>
Tue, 16 Mar 2010 16:12:26 +0000
branchSymbian2
changeset 2 2fe1408b6811
permissions -rw-r--r--
Final list of Symbian^2 public API header files
     1 //  © Copyright Fernando Luis Cacciola Carballal 2000-2004
     2 //  Use, modification, and distribution is subject to the Boost Software
     3 //  License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
     4 //  http://www.boost.org/LICENSE_1_0.txt)
     5 
     6 //  See library home page at http://www.boost.org/libs/numeric/conversion
     7 //
     8 // Contact the author at: fernando_cacciola@hotmail.com
     9 // 
    10 #ifndef BOOST_NUMERIC_CONVERSION_DETAIL_META_FLC_12NOV2002_HPP
    11 #define BOOST_NUMERIC_CONVERSION_DETAIL_META_FLC_12NOV2002_HPP
    12 
    13 #include "boost/type_traits/remove_cv.hpp"
    14 
    15 #include "boost/mpl/if.hpp"
    16 #include "boost/mpl/eval_if.hpp"
    17 #include "boost/mpl/equal_to.hpp"
    18 #include "boost/mpl/not.hpp"
    19 #include "boost/mpl/and.hpp"
    20 #include "boost/mpl/bool.hpp"
    21 #include "boost/mpl/identity.hpp"
    22 
    23 namespace boost { namespace numeric { namespace convdetail
    24 {
    25    template< class T1, class T2>
    26    struct equal_to
    27    {
    28    #if !defined(__BORLANDC__)
    29    
    30        enum { x = ( BOOST_MPL_AUX_VALUE_WKND(T1)::value == BOOST_MPL_AUX_VALUE_WKND(T2)::value ) };
    31            
    32        BOOST_STATIC_CONSTANT(bool, value = x);
    33            
    34        typedef mpl::bool_<value> type;
    35        
    36    #else
    37    
    38        BOOST_STATIC_CONSTANT(bool, value = (
    39              BOOST_MPL_AUX_VALUE_WKND(T1)::value 
    40                == BOOST_MPL_AUX_VALUE_WKND(T2)::value
    41            ));
    42            
    43        typedef mpl::bool_<(
    44              BOOST_MPL_AUX_VALUE_WKND(T1)::value 
    45                == BOOST_MPL_AUX_VALUE_WKND(T2)::value
    46            )> type;
    47    #endif
    48    };
    49     
    50 // Metafunction:
    51   //
    52   //   ct_switch4<Value,Case0Val,Case1Val,Case2Val,Case0Type,Case1Type,Case2Type,DefaultType>::type
    53   //
    54   // {Value,Case(X)Val} are Integral Constants (such as: mpl::int_<>)
    55   // {Case(X)Type,DefaultType} are arbitrary types. (not metafunctions)
    56   //
    57   // Returns Case(X)Type if Val==Case(X)Val; DefaultType otherwise.
    58   //
    59   template<class Value,
    60            class Case0Val,
    61            class Case1Val,
    62            class Case2Val,
    63            class Case0Type,
    64            class Case1Type,
    65            class Case2Type,
    66            class DefaultType
    67           >
    68   struct ct_switch4
    69   {
    70     typedef mpl::identity<Case0Type> Case0TypeQ ;
    71     typedef mpl::identity<Case1Type> Case1TypeQ ;
    72 
    73     typedef equal_to<Value,Case0Val> is_case0 ;
    74     typedef equal_to<Value,Case1Val> is_case1 ;
    75     typedef equal_to<Value,Case2Val> is_case2 ;
    76 
    77     typedef mpl::if_<is_case2,Case2Type,DefaultType> choose_2_3Q ;
    78     typedef mpl::eval_if<is_case1,Case1TypeQ,choose_2_3Q> choose_1_2_3Q ;
    79 
    80     typedef typename
    81       mpl::eval_if<is_case0,Case0TypeQ,choose_1_2_3Q>::type
    82         type ;
    83   } ;
    84 
    85 
    86 
    87 
    88   // Metafunction:
    89   //
    90   //   for_both<expr0,expr1,TT,TF,FT,FF>::type
    91   //
    92   // {exp0,expr1} are Boolean Integral Constants
    93   // {TT,TF,FT,FF} are aribtrary types. (not metafunctions)
    94   //
    95   // According to the combined boolean value of 'expr0 && expr1', selects the corresponding type.
    96   //
    97   template<class expr0, class expr1, class TT, class TF, class FT, class FF>
    98   struct for_both
    99   {
   100     typedef mpl::identity<TF> TF_Q ;
   101     typedef mpl::identity<TT> TT_Q ;
   102 
   103     typedef typename mpl::not_<expr0>::type not_expr0 ;
   104     typedef typename mpl::not_<expr1>::type not_expr1 ;
   105 
   106     typedef typename mpl::and_<expr0,expr1>::type     caseTT ;
   107     typedef typename mpl::and_<expr0,not_expr1>::type caseTF ;
   108     typedef typename mpl::and_<not_expr0,expr1>::type caseFT ;
   109 
   110     typedef mpl::if_<caseFT,FT,FF>                    choose_FT_FF_Q ;
   111     typedef mpl::eval_if<caseTF,TF_Q,choose_FT_FF_Q> choose_TF_FT_FF_Q ;
   112 
   113     typedef typename mpl::eval_if<caseTT,TT_Q,choose_TF_FT_FF_Q>::type type ;
   114   } ;
   115 
   116 } } } // namespace boost::numeric::convdetail
   117 
   118 #endif
   119 
   120