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