boost/boost/multiprecision/traits/is_restricted_conversion.hpp

///////////////////////////////////////////////////////////////////////////////
//  Copyright Vicente J. Botet Escriba 2009-2011
//  Copyright 2012 John Maddock. Distributed under 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)

#ifndef BOOST_MP_RESTRICTED_CONVERSION_HPP
#define BOOST_MP_RESTRICTED_CONVERSION_HPP

#include <boost/multiprecision/traits/explicit_conversion.hpp>
#include <boost/mpl/if.hpp>
#include <boost/multiprecision/detail/number_base.hpp>

namespace boost{ namespace multiprecision{ namespace detail{


template <class From, class To>
struct is_lossy_conversion
{
   typedef typename mpl::if_c<
      ((number_category<From>::value == number_kind_floating_point) && (number_category<To>::value == number_kind_integer))
      /* || ((number_category<From>::value == number_kind_floating_point) && (number_category<To>::value == number_kind_rational))*/
      || ((number_category<From>::value == number_kind_rational) && (number_category<To>::value == number_kind_integer))
      || ((number_category<From>::value == number_kind_fixed_point) && (number_category<To>::value == number_kind_integer))
      || (number_category<From>::value == number_kind_unknown)
      || (number_category<To>::value == number_kind_unknown),
      mpl::true_,
      mpl::false_
   >::type type;
   static const bool value = type::value;
};

template<typename From, typename To>
struct is_restricted_conversion
{
   typedef typename mpl::if_c<
      ((is_explicitly_convertible<From, To>::value && !is_convertible<From, To>::value)
      || is_lossy_conversion<From, To>::value),
      mpl::true_,
      mpl::false_
   >::type type;
   static const bool value = type::value;
};

}}} // namespaces

#endif // BOOST_MP_RESTRICTED_CONVERSION_HPP