boost/type_traits/floating_point_promotion.hpp

   1 // Copyright 2005 Alexander Nasonov.
   2 // Distributed under the Boost Software License, Version 1.0. (See
   3 // accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #ifndef FILE_boost_type_traits_floating_point_promotion_hpp_INCLUDED
   7 #define FILE_boost_type_traits_floating_point_promotion_hpp_INCLUDED
   8
   9 #include <boost/config.hpp>
  10
  11 #ifdef BOOST_NO_CV_SPECIALIZATIONS
  12 #include <boost/mpl/at.hpp>
  13 #include <boost/mpl/int.hpp>
  14 #include <boost/mpl/multiplies.hpp>
  15 #include <boost/mpl/plus.hpp>
  16 #include <boost/mpl/vector.hpp>
  17 #include <boost/type_traits/is_same.hpp>
  18 #endif
  19
  20 // Should be the last #include
  21 #include <boost/type_traits/detail/type_trait_def.hpp>
  22
  23 namespace boost {
  24
  25 namespace type_traits { namespace detail {
  26
  27 #ifndef BOOST_NO_CV_SPECIALIZATIONS
  28
  29 template<class T>
  30 struct floating_point_promotion
  31 {
  32     typedef T type;
  33 };
  34
  35 template<>
  36 struct floating_point_promotion<float>
  37 {
  38     typedef double type;
  39 };
  40
  41 template<>
  42 struct floating_point_promotion<float const>
  43 {
  44     typedef double const type;
  45 };
  46
  47 template<>
  48 struct floating_point_promotion<float volatile>
  49 {
  50     typedef double volatile type;
  51 };
  52
  53 template<>
  54 struct floating_point_promotion<float const volatile>
  55 {
  56     typedef double const volatile type;
  57 };
  58
  59 #else
  60
  61 template<class T>
  62 struct floating_point_promotion
  63   : mpl::at<
  64         mpl::vector< T, double, double const, double volatile,
  65                      double const volatile >
  66       , mpl::plus<
  67             is_same<T, float>
  68           , mpl::multiplies< is_same<T, float const>         , mpl::int_<2> >
  69           , mpl::multiplies< is_same<T, float volatile>      , mpl::int_<3> >
  70           , mpl::multiplies< is_same<T, float const volatile>, mpl::int_<4> >
  71           >
  72       >
  73 {
  74 };
  75
  76 #endif
  77
  78 } }
  79
  80 BOOST_TT_AUX_TYPE_TRAIT_DEF1(
  81       floating_point_promotion
  82     , T
  83     , BOOST_DEDUCED_TYPENAME
  84         boost::type_traits::detail::floating_point_promotion<T>::type
  85     )
  86 }
  87
  88 #include <boost/type_traits/detail/type_trait_undef.hpp>
  89
  90 #endif // #ifndef FILE_boost_type_traits_floating_point_promotion_hpp_INCLUDED
  91