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_HETEROGENEOUS_SYSTEM_HPP
Chris@16: #define BOOST_UNITS_HETEROGENEOUS_SYSTEM_HPP
Chris@16: 
Chris@16: /// \file
Chris@16: /// \brief A heterogeneous system is a sorted list of base unit/exponent pairs.
Chris@16: 
Chris@16: #include <boost/mpl/bool.hpp>
Chris@16: #include <boost/mpl/plus.hpp>
Chris@16: #include <boost/mpl/times.hpp>
Chris@16: #include <boost/mpl/divides.hpp>
Chris@16: #include <boost/mpl/negate.hpp>
Chris@16: #include <boost/mpl/less.hpp>
Chris@16: #include <boost/mpl/size.hpp>
Chris@16: #include <boost/mpl/begin.hpp>
Chris@16: #include <boost/mpl/next.hpp>
Chris@16: #include <boost/mpl/deref.hpp>
Chris@16: #include <boost/mpl/front.hpp>
Chris@16: #include <boost/mpl/push_front.hpp>
Chris@16: #include <boost/mpl/pop_front.hpp>
Chris@16: #include <boost/mpl/assert.hpp>
Chris@16: #include <boost/type_traits/is_same.hpp>
Chris@16: 
Chris@16: #include <boost/units/config.hpp>
Chris@16: #include <boost/units/static_rational.hpp>
Chris@16: #include <boost/units/dimension.hpp>
Chris@16: #include <boost/units/units_fwd.hpp>
Chris@16: #include <boost/units/detail/push_front_if.hpp>
Chris@16: #include <boost/units/detail/push_front_or_add.hpp>
Chris@16: #include <boost/units/detail/linear_algebra.hpp>
Chris@16: #include <boost/units/detail/unscale.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: namespace units {
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: // A normal system is a sorted list of base units.
Chris@16: // A heterogeneous system is a sorted list of base unit/exponent pairs.
Chris@16: // As long as we don't need to convert heterogeneous systems
Chris@16: // directly everything is cool.
Chris@16: 
Chris@16: template<class T>
Chris@16: struct is_zero : mpl::false_ {};
Chris@16: 
Chris@16: template<>
Chris@16: struct is_zero<static_rational<0> > : mpl::true_ {};
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<class L, class Dimensions, class Scale>
Chris@16: struct heterogeneous_system_impl
Chris@16: {
Chris@16:     typedef L type;
Chris@16:     typedef Dimensions dimensions;
Chris@16:     typedef Scale scale;
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: typedef dimensionless_type no_scale;
Chris@16: 
Chris@16: /// A system that can represent any possible combination
Chris@16: /// of units at the expense of not preserving information
Chris@16: /// about how it was created.  Do not create specializations
Chris@16: /// of this template directly. Instead use @c reduce_unit and
Chris@16: /// @c base_unit<...>::unit_type.
Chris@16: template<class T>
Chris@16: struct heterogeneous_system : T {};
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: struct heterogeneous_system_dim_tag {};
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<class Unit, class Exponent>
Chris@16: struct heterogeneous_system_dim
Chris@16: {
Chris@16:     typedef heterogeneous_system_dim_tag tag;
Chris@16:     typedef heterogeneous_system_dim type;
Chris@16:     typedef Unit tag_type;
Chris@16:     typedef Exponent value_type;
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: #define BOOST_UNITS_MAKE_HETEROGENEOUS_UNIT(BaseUnit, Dimensions)   \
Chris@16:     boost::units::unit<                                             \
Chris@16:         Dimensions,                                                 \
Chris@16:         boost::units::heterogeneous_system<                         \
Chris@16:             boost::units::heterogeneous_system_impl<                \
Chris@16:                 boost::units::list<                       \
Chris@16:                     boost::units::heterogeneous_system_dim<         \
Chris@16:                         BaseUnit,                                   \
Chris@16:                         boost::units::static_rational<1>            \
Chris@16:                     >,                                              \
Chris@16:                     boost::units::dimensionless_type                \
Chris@16:                 >,                                                  \
Chris@16:                 Dimensions,                                         \
Chris@16:                 boost::units::no_scale                              \
Chris@16:             >                                                       \
Chris@16:         >                                                           \
Chris@16:     >
Chris@16: 
Chris@16: } // namespace units
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
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::heterogeneous_system_impl, (class)(class)(class))
Chris@16: BOOST_TYPEOF_REGISTER_TEMPLATE(boost::units::heterogeneous_system, (class))
Chris@16: BOOST_TYPEOF_REGISTER_TEMPLATE(boost::units::heterogeneous_system_dim, (class)(class))
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: namespace mpl {
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<>
Chris@16: struct less_impl<boost::units::heterogeneous_system_dim_tag, boost::units::heterogeneous_system_dim_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply : mpl::less<typename T0::tag_type, typename T1::tag_type> {};
Chris@16: };
Chris@16: 
Chris@16: }
Chris@16: 
Chris@16: namespace units {
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: template<class Unit1, class Exponent1>
Chris@16: struct is_empty_dim<heterogeneous_system_dim<Unit1,Exponent1> > : detail::is_zero<Exponent1> {};
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: } // namespace units
Chris@16: 
Chris@16: namespace mpl {
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<>
Chris@16: struct plus_impl<boost::units::heterogeneous_system_dim_tag, boost::units::heterogeneous_system_dim_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef boost::units::heterogeneous_system_dim<
Chris@16:             typename T0::tag_type,
Chris@16:             typename mpl::plus<typename T0::value_type,typename T1::value_type>::type
Chris@16:         > type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<>
Chris@16: struct times_impl<boost::units::heterogeneous_system_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::heterogeneous_system_dim<
Chris@16:             typename T0::tag_type,
Chris@16:             typename mpl::times<typename T0::value_type,T1>::type
Chris@16:         > type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<>
Chris@16: struct divides_impl<boost::units::heterogeneous_system_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::heterogeneous_system_dim<
Chris@16:             typename T0::tag_type,
Chris@16:             typename mpl::divides<typename T0::value_type,T1>::type
Chris@16:         > type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<>
Chris@16: struct negate_impl<boost::units::heterogeneous_system_dim_tag>
Chris@16: {
Chris@16:     template<class T>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef boost::units::heterogeneous_system_dim<typename T::tag_type, typename mpl::negate<typename T::value_type>::type> type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: } // namespace mpl
Chris@16: 
Chris@16: namespace units {
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: template<int N>
Chris@16: struct make_heterogeneous_system_impl
Chris@16: {
Chris@16:     template<class UnitsBegin, class ExponentsBegin>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef typename push_front_if<!(is_zero<typename ExponentsBegin::item>::value)>::template apply<
Chris@16:             typename make_heterogeneous_system_impl<N-1>::template apply<
Chris@16:                 typename UnitsBegin::next,
Chris@16:                 typename ExponentsBegin::next
Chris@16:             >::type,
Chris@16:             heterogeneous_system_dim<typename UnitsBegin::item, typename ExponentsBegin::item>
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct make_heterogeneous_system_impl<0>
Chris@16: {
Chris@16:     template<class UnitsBegin, class ExponentsBegin>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef dimensionless_type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<class Dimensions, class System>
Chris@16: struct make_heterogeneous_system
Chris@16: {
Chris@16:     typedef typename calculate_base_unit_exponents<typename System::type, Dimensions>::type exponents;
Chris@16:     BOOST_MPL_ASSERT_MSG((!boost::is_same<exponents, inconsistent>::value), the_specified_dimension_is_not_representible_in_the_given_system, (types<Dimensions, System>));
Chris@16:     typedef typename make_heterogeneous_system_impl<System::type::size::value>::template apply<
Chris@16:         typename System::type,
Chris@16:         exponents
Chris@16:     >::type unit_list;
Chris@16:     typedef heterogeneous_system<heterogeneous_system_impl<unit_list, Dimensions, no_scale> > type;
Chris@16: };
Chris@16: 
Chris@16: template<class Dimensions, class T>
Chris@16: struct make_heterogeneous_system<Dimensions, heterogeneous_system<T> >
Chris@16: {
Chris@16:     typedef heterogeneous_system<T> type;
Chris@16: };
Chris@16: 
Chris@16: template<class T0, class T1>
Chris@16: struct multiply_systems
Chris@16: {
Chris@16:     typedef heterogeneous_system<
Chris@16:         heterogeneous_system_impl<
Chris@16:             typename mpl::times<typename T0::type, typename T1::type>::type,
Chris@16:             typename mpl::times<typename T0::dimensions, typename T1::dimensions>::type,
Chris@16:             typename mpl::times<typename T0::scale, typename T1::scale>::type
Chris@16:         >
Chris@16:     > type;
Chris@16: };
Chris@16: 
Chris@16: template<class T0, class T1>
Chris@16: struct divide_systems
Chris@16: {
Chris@16:     typedef heterogeneous_system<
Chris@16:         heterogeneous_system_impl<
Chris@16:             typename mpl::divides<typename T0::type, typename T1::type>::type,
Chris@16:             typename mpl::divides<typename T0::dimensions, typename T1::dimensions>::type,
Chris@16:             typename mpl::divides<typename T0::scale, typename T1::scale>::type
Chris@16:         >
Chris@16:     > type;
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<class S, long N, long D>
Chris@16: struct static_power<heterogeneous_system<S>, static_rational<N,D> >
Chris@16: {
Chris@16:     typedef heterogeneous_system<
Chris@16:         heterogeneous_system_impl<
Chris@16:             typename static_power<typename S::type, static_rational<N,D> >::type,
Chris@16:             typename static_power<typename S::dimensions, static_rational<N,D> >::type,
Chris@16:             typename static_power<typename S::scale, static_rational<N,D> >::type
Chris@16:         >
Chris@16:     > type;
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<class S, long N, long D>
Chris@16: struct static_root<heterogeneous_system<S>, static_rational<N,D> >
Chris@16: {
Chris@16:     typedef heterogeneous_system<
Chris@16:         heterogeneous_system_impl<
Chris@16:             typename static_root<typename S::type, static_rational<N,D> >::type,
Chris@16:             typename static_root<typename S::dimensions, static_rational<N,D> >::type,
Chris@16:             typename static_root<typename S::scale, static_rational<N,D> >::type
Chris@16:         >
Chris@16:     > type;
Chris@16: };
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: template<int N>
Chris@16: struct unscale_heterogeneous_system_impl
Chris@16: {
Chris@16:     template<class Begin>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef typename push_front_or_add<
Chris@16:             typename unscale_heterogeneous_system_impl<N-1>::template apply<
Chris@16:                 typename Begin::next
Chris@16:             >::type,
Chris@16:             typename unscale<typename Begin::item>::type
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct unscale_heterogeneous_system_impl<0>
Chris@16: {
Chris@16:     template<class Begin>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef dimensionless_type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: /// Unscale all the base units. e.g
Chris@16: /// km s -> m s
Chris@16: /// cm km -> m^2
Chris@16: /// INTERNAL ONLY
Chris@16: template<class T>
Chris@16: struct unscale<heterogeneous_system<T> >
Chris@16: {
Chris@16:     typedef heterogeneous_system<
Chris@16:         heterogeneous_system_impl<
Chris@16:             typename detail::unscale_heterogeneous_system_impl<
Chris@16:                 T::type::size::value
Chris@16:             >::template apply<
Chris@16:                 typename T::type
Chris@16:             >::type,
Chris@16:             typename T::dimensions,
Chris@16:             no_scale
Chris@16:         >
Chris@16:     > type;
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<class Unit, class Exponent>
Chris@16: struct unscale<heterogeneous_system_dim<Unit, Exponent> >
Chris@16: {
Chris@16:     typedef heterogeneous_system_dim<typename unscale<Unit>::type, Exponent> type;
Chris@16: };
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: template<int N>
Chris@16: struct get_scale_list_of_heterogeneous_system_impl
Chris@16: {
Chris@16:     template<class Begin>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef typename mpl::times<
Chris@16:             typename get_scale_list_of_heterogeneous_system_impl<N-1>::template apply<
Chris@16:                 typename Begin::next
Chris@16:             >::type,
Chris@16:             typename get_scale_list<typename Begin::item>::type
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct get_scale_list_of_heterogeneous_system_impl<0>
Chris@16: {
Chris@16:     template<class Begin>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef dimensionless_type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<class T>
Chris@16: struct get_scale_list<heterogeneous_system<T> >
Chris@16: {
Chris@16:     typedef typename mpl::times<
Chris@16:         typename detail::get_scale_list_of_heterogeneous_system_impl<
Chris@16:             T::type::size::value
Chris@16:         >::template apply<typename T::type>::type,
Chris@16:         typename T::scale
Chris@16:     >::type type;
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<class Unit, class Exponent>
Chris@16: struct get_scale_list<heterogeneous_system_dim<Unit, Exponent> >
Chris@16: {
Chris@16:     typedef typename static_power<typename get_scale_list<Unit>::type, Exponent>::type type;
Chris@16: };
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: template<class System, class Dimension>
Chris@16: struct check_system : mpl::false_ {};
Chris@16: 
Chris@16: template<class System, class Dimension, class Scale>
Chris@16: struct check_system<heterogeneous_system<heterogeneous_system_impl<System, Dimension, Scale> >, Dimension> : mpl::true_ {};
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: } // namespace units
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif