| // 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) 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_DIMENSION_IMPL_HPP |
| #define BOOST_UNITS_DIMENSION_IMPL_HPP |
| |
| #include <boost/mpl/begin_end.hpp> |
| #include <boost/mpl/deref.hpp> |
| #include <boost/mpl/if.hpp> |
| #include <boost/mpl/list.hpp> |
| #include <boost/mpl/next.hpp> |
| #include <boost/mpl/size.hpp> |
| #include <boost/mpl/less.hpp> |
| |
| #include <boost/units/config.hpp> |
| #include <boost/units/dimensionless_type.hpp> |
| #include <boost/units/static_rational.hpp> |
| #include <boost/units/units_fwd.hpp> |
| #include <boost/units/detail/dimension_list.hpp> |
| #include <boost/units/detail/push_front_if.hpp> |
| #include <boost/units/detail/push_front_or_add.hpp> |
| |
| /// \file |
| /// \brief Core class and metaprogramming utilities for compile-time dimensional analysis. |
| |
| namespace boost { |
| |
| namespace units { |
| |
| namespace detail { |
| |
| template<int N> |
| struct insertion_sort_dims_insert; |
| |
| template<bool is_greater> |
| struct insertion_sort_dims_comparison_impl; |
| |
| // have to recursively add the element to the next sequence. |
| template<> |
| struct insertion_sort_dims_comparison_impl<true> { |
| template<class Begin, int N, class T> |
| struct apply { |
| typedef list< |
| typename Begin::item, |
| typename insertion_sort_dims_insert<N - 1>::template apply< |
| typename Begin::next, |
| T |
| >::type |
| > type; |
| }; |
| }; |
| |
| // either prepend the current element or join it to |
| // the first remaining element of the sequence. |
| template<> |
| struct insertion_sort_dims_comparison_impl<false> { |
| template<class Begin, int N, class T> |
| struct apply { |
| typedef typename push_front_or_add<Begin, T>::type type; |
| }; |
| }; |
| |
| template<int N> |
| struct insertion_sort_dims_insert { |
| template<class Begin, class T> |
| struct apply { |
| typedef typename insertion_sort_dims_comparison_impl<mpl::less<typename Begin::item, T>::value>::template apply< |
| Begin, |
| N, |
| T |
| >::type type; |
| }; |
| }; |
| |
| template<> |
| struct insertion_sort_dims_insert<0> { |
| template<class Begin, class T> |
| struct apply { |
| typedef list<T, dimensionless_type> type; |
| }; |
| }; |
| |
| template<int N> |
| struct insertion_sort_dims_mpl_sequence { |
| template<class Begin> |
| struct apply { |
| typedef typename insertion_sort_dims_mpl_sequence<N - 1>::template apply<typename mpl::next<Begin>::type>::type next; |
| typedef typename insertion_sort_dims_insert<(next::size::value)>::template apply<next, typename mpl::deref<Begin>::type>::type type; |
| }; |
| }; |
| |
| template<> |
| struct insertion_sort_dims_mpl_sequence<0> { |
| template<class Begin> |
| struct apply { |
| typedef dimensionless_type type; |
| }; |
| }; |
| |
| template<int N> |
| struct insertion_sort_dims_impl { |
| template<class Begin> |
| struct apply { |
| typedef typename insertion_sort_dims_impl<N - 1>::template apply<typename Begin::next>::type next; |
| typedef typename insertion_sort_dims_insert<(next::size::value)>::template apply<next, typename Begin::item>::type type; |
| }; |
| }; |
| |
| template<> |
| struct insertion_sort_dims_impl<0> { |
| template<class Begin> |
| struct apply { |
| typedef dimensionless_type type; |
| }; |
| }; |
| |
| template<class T> |
| struct sort_dims |
| { |
| typedef typename insertion_sort_dims_mpl_sequence<mpl::size<T>::value>::template apply<typename mpl::begin<T>::type>::type type; |
| }; |
| |
| |
| template<class T, class Next> |
| struct sort_dims<list<T, Next> > |
| { |
| typedef typename insertion_sort_dims_impl<list<T, Next>::size::value>::template apply<list<T, Next> >::type type; |
| }; |
| |
| /// sorted sequences can be merged in linear time |
| template<bool less, bool greater> |
| struct merge_dimensions_func; |
| |
| template<int N1, int N2> |
| struct merge_dimensions_impl; |
| |
| template<> |
| struct merge_dimensions_func<true, false> |
| { |
| template<typename Begin1, typename Begin2, int N1, int N2> |
| struct apply |
| { |
| typedef list< |
| typename Begin1::item, |
| typename merge_dimensions_impl<N1 - 1, N2>::template apply< |
| typename Begin1::next, |
| Begin2 |
| >::type |
| > type; |
| }; |
| }; |
| |
| template<> |
| struct merge_dimensions_func<false, true> { |
| template<typename Begin1, typename Begin2, int N1, int N2> |
| struct apply |
| { |
| typedef list< |
| typename Begin2::item, |
| typename merge_dimensions_impl<N2 - 1, N1>::template apply< |
| typename Begin2::next, |
| Begin1 |
| >::type |
| > type; |
| }; |
| }; |
| |
| template<> |
| struct merge_dimensions_func<false, false> { |
| template<typename Begin1, typename Begin2, int N1, int N2> |
| struct apply |
| { |
| typedef typename mpl::plus<typename Begin1::item, typename Begin2::item>::type combined; |
| typedef typename push_front_if<!is_empty_dim<combined>::value>::template apply< |
| typename merge_dimensions_impl<N1 - 1, N2 - 1>::template apply< |
| typename Begin1::next, |
| typename Begin2::next |
| >::type, |
| combined |
| >::type type; |
| }; |
| }; |
| |
| template<int N1, int N2> |
| struct merge_dimensions_impl { |
| template<typename Begin1, typename Begin2> |
| struct apply |
| { |
| typedef typename Begin1::item dim1; |
| typedef typename Begin2::item dim2; |
| |
| typedef typename merge_dimensions_func<(mpl::less<dim1,dim2>::value == true), |
| (mpl::less<dim2,dim1>::value == true)>::template apply< |
| Begin1, |
| Begin2, |
| N1, |
| N2 |
| >::type type; |
| }; |
| }; |
| |
| template<typename Sequence1, typename Sequence2> |
| struct merge_dimensions |
| { |
| typedef typename detail::merge_dimensions_impl<Sequence1::size::value, |
| Sequence2::size::value>::template |
| apply< |
| Sequence1, |
| Sequence2 |
| >::type type; |
| }; |
| |
| template<int N> |
| struct iterator_to_list |
| { |
| template<typename Begin> |
| struct apply |
| { |
| typedef list< |
| typename Begin::item, |
| typename iterator_to_list<N - 1>::template apply< |
| typename Begin::next |
| >::type |
| > type; |
| }; |
| }; |
| |
| template<> |
| struct iterator_to_list<0> |
| { |
| template<typename Begin> |
| struct apply { |
| typedef dimensionless_type type; |
| }; |
| }; |
| |
| template<int N> |
| struct merge_dimensions_impl<N, 0> |
| { |
| template<typename Begin1, typename Begin2> |
| struct apply |
| { |
| typedef typename iterator_to_list<N>::template apply<Begin1>::type type; |
| }; |
| }; |
| |
| template<int N> |
| struct merge_dimensions_impl<0, N> |
| { |
| template<typename Begin1, typename Begin2> |
| struct apply |
| { |
| typedef typename iterator_to_list<N>::template apply<Begin2>::type type; |
| }; |
| }; |
| |
| template<> |
| struct merge_dimensions_impl<0, 0> |
| { |
| template<typename Begin1, typename Begin2> |
| struct apply |
| { |
| typedef dimensionless_type type; |
| }; |
| }; |
| |
| template<int N> |
| struct static_inverse_impl |
| { |
| template<typename Begin> |
| struct apply { |
| typedef list< |
| typename mpl::negate<typename Begin::item>::type, |
| typename static_inverse_impl<N - 1>::template apply< |
| typename Begin::next |
| >::type |
| > type; |
| }; |
| }; |
| |
| template<> |
| struct static_inverse_impl<0> |
| { |
| template<typename Begin> |
| struct apply |
| { |
| typedef dimensionless_type type; |
| }; |
| }; |
| |
| template<int N> |
| struct static_power_impl |
| { |
| template<typename Begin, typename Ex> |
| struct apply |
| { |
| typedef list< |
| typename mpl::times<typename Begin::item, Ex>::type, |
| typename detail::static_power_impl<N - 1>::template apply<typename Begin::next, Ex>::type |
| > type; |
| }; |
| }; |
| |
| template<> |
| struct static_power_impl<0> |
| { |
| template<typename Begin, typename Ex> |
| struct apply |
| { |
| typedef dimensionless_type type; |
| }; |
| }; |
| |
| template<int N> |
| struct static_root_impl { |
| template<class Begin, class Ex> |
| struct apply { |
| typedef list< |
| typename mpl::divides<typename Begin::item, Ex>::type, |
| typename detail::static_root_impl<N - 1>::template apply<typename Begin::next, Ex>::type |
| > type; |
| }; |
| }; |
| |
| template<> |
| struct static_root_impl<0> { |
| template<class Begin, class Ex> |
| struct apply |
| { |
| typedef dimensionless_type type; |
| }; |
| }; |
| |
| } // namespace detail |
| |
| } // namespace units |
| |
| } // namespace boost |
| |
| #endif // BOOST_UNITS_DIMENSION_IMPL_HPP |