Boost_1_39_0/boost/tr1/detail/math_overloads.hpp

   1 //  (C) Copyright John Maddock 2005.
   2 //  Use, modification and distribution are subject to the
   3 //  Boost Software License, Version 1.0. (See accompanying file
   4 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #ifndef BOOST_TR1_MATH_OVERLOADS_HPP_INCLUDED
   7 #  define BOOST_TR1_MATH_OVERLOADS_HPP_INCLUDED
   8 #  include <boost/config.hpp>
   9
  10 #  ifndef BOOST_NO_SFINAE
  11 #     include <boost/utility/enable_if.hpp>
  12 #     include <boost/type_traits/is_convertible.hpp>
  13 #     define BOOST_TR1_MATH_RETURN(RET) typename ::boost::enable_if< ::boost::is_convertible<T,double>, RET >::type
  14 #  else
  15 #     define BOOST_TR1_MATH_RETURN(RET) RET
  16 #  endif
  17
  18 #  include <boost/type_traits/is_floating_point.hpp>
  19 #  include <boost/type_traits/is_same.hpp>
  20 #  include <boost/mpl/if.hpp>
  21
  22 namespace boost{ namespace tr1_detail{
  23
  24 template <class T, class U>
  25 struct largest_real
  26 {
  27    typedef typename boost::mpl::if_<
  28       boost::is_same<long double, T>,
  29       long double,
  30       typename boost::mpl::if_<
  31          boost::is_same<long double, U>,
  32          long double,
  33          typename boost::mpl::if_<
  34             boost::is_same<double, T>,
  35             double,
  36             typename boost::mpl::if_<
  37                boost::is_same<double, U>,
  38                double,
  39                float
  40             >::type
  41          >::type
  42       >::type
  43    >::type type;
  44 };
  45
  46 template <class T, class U>
  47 struct promote_to_real
  48 {
  49    typedef typename largest_real<
  50       typename boost::mpl::if_< boost::is_floating_point<T>, T, double>::type,
  51       typename boost::mpl::if_< boost::is_floating_point<U>, U, double>::type
  52    >::type type;
  53 };
  54
  55 } }
  56
  57 #endif
  58