Chris@16: // Boost.Units - A C++ library for zero-overhead dimensional analysis and 
Chris@16: // unit/quantity manipulation and conversion
Chris@16: //
Chris@16: // Copyright (C) 2003-2008 Matthias Christian Schabel
Chris@16: // Copyright (C) 2007-2008 Steven Watanabe
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_UNITS_DIM_HPP
Chris@16: #define BOOST_UNITS_DIM_HPP
Chris@16: 
Chris@16: #include <boost/static_assert.hpp>
Chris@16: 
Chris@16: #include <boost/type_traits/is_same.hpp>
Chris@16: 
Chris@16: #include <boost/mpl/arithmetic.hpp>
Chris@16: 
Chris@16: #include <boost/units/config.hpp>
Chris@16: #include <boost/units/static_rational.hpp>
Chris@16: #include <boost/units/detail/dim_impl.hpp>
Chris@16: 
Chris@16: /// \file dim.hpp
Chris@16: /// \brief Handling of fundamental dimension/exponent pairs.
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: namespace units {
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: struct dim_tag { };
Chris@16: 
Chris@16: }
Chris@16: 
Chris@16: /// \brief Dimension tag/exponent pair for a single fundamental dimension.
Chris@16: ///
Chris@16: /// \details 
Chris@16: /// The dim class represents a single dimension tag/dimension exponent pair.
Chris@16: /// That is, @c dim<tag_type,value_type> is a pair where @c tag_type represents the
Chris@16: /// fundamental dimension being represented and @c value_type represents the 
Chris@16: /// exponent of that fundamental dimension as a @c static_rational. @c tag_type must 
Chris@16: /// be a derived from a specialization of @c base_dimension.
Chris@16: /// Specialization of the following Boost.MPL metafunctions are provided
Chris@16: ///
Chris@16: ///     - @c mpl::plus for two @c dims
Chris@16: ///     - @c mpl::minus for two @c dims
Chris@16: ///     - @c mpl::negate for a @c dim
Chris@16: ///
Chris@16: /// These metafunctions all operate on the exponent, and require
Chris@16: /// that the @c dim operands have the same base dimension tag.
Chris@16: /// In addition, multiplication and division by @c static_rational
Chris@16: /// is supported.
Chris@16: ///
Chris@16: ///     - @c mpl::times for a @c static_rational and a @c dim in either order
Chris@16: ///     - @c mpl::divides for a @c static_rational and a @c dim in either order
Chris@16: ///
Chris@16: /// These metafunctions likewise operate on the exponent only.
Chris@16: template<typename T,typename V> 
Chris@16: struct dim
Chris@16: {
Chris@16:     typedef dim             type;
Chris@16:     typedef detail::dim_tag tag;
Chris@16:     typedef T               tag_type;
Chris@16:     typedef V               value_type;
Chris@16: };
Chris@16: 
Chris@16: } // namespace units
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #if BOOST_UNITS_HAS_BOOST_TYPEOF
Chris@16: 
Chris@16: #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP()
Chris@16: 
Chris@16: BOOST_TYPEOF_REGISTER_TEMPLATE(boost::units::dim, 2)
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: #ifndef BOOST_UNITS_DOXYGEN
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: namespace mpl {
Chris@16: 
Chris@16: // define MPL operators acting on dim<T,V>
Chris@16: 
Chris@16: template<>
Chris@16: struct plus_impl<boost::units::detail::dim_tag,boost::units::detail::dim_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         BOOST_STATIC_ASSERT((boost::is_same<typename T0::tag_type,typename T1::tag_type>::value == true));
Chris@16:         typedef boost::units::dim<typename T0::tag_type, typename mpl::plus<typename T0::value_type, typename T1::value_type>::type> type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct minus_impl<boost::units::detail::dim_tag,boost::units::detail::dim_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         BOOST_STATIC_ASSERT((boost::is_same<typename T0::tag_type,typename T1::tag_type>::value == true));
Chris@16:         typedef boost::units::dim<typename T0::tag_type, typename mpl::minus<typename T0::value_type, typename T1::value_type>::type> type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct times_impl<boost::units::detail::dim_tag,boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef boost::units::dim<typename T0::tag_type, typename mpl::times<typename T0::value_type, T1>::type> type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct times_impl<boost::units::detail::static_rational_tag,boost::units::detail::dim_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef boost::units::dim<typename T1::tag_type, typename mpl::times<T0, typename T1::value_type>::type> type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct divides_impl<boost::units::detail::dim_tag,boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef boost::units::dim<typename T0::tag_type, typename mpl::divides<typename T0::value_type, T1>::type> type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct divides_impl<boost::units::detail::static_rational_tag,boost::units::detail::dim_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef boost::units::dim<typename T1::tag_type, typename mpl::divides<T0, typename T1::value_type>::type> type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct negate_impl<boost::units::detail::dim_tag>
Chris@16: {
Chris@16:     template<class T0>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef boost::units::dim<typename T0::tag_type,typename mpl::negate<typename T0::value_type>::type> type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: } // namespace mpl
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: #endif // BOOST_UNITS_DIM_HPP