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-rw-r--r--boost/units/detail/heterogeneous_conversion.hpp309
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+// 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_DETAIL_HETEROGENEOUS_CONVERSION_HPP
+#define BOOST_UNITS_DETAIL_HETEROGENEOUS_CONVERSION_HPP
+
+#include <boost/mpl/minus.hpp>
+#include <boost/mpl/times.hpp>
+
+#include <boost/units/static_rational.hpp>
+#include <boost/units/homogeneous_system.hpp>
+#include <boost/units/detail/linear_algebra.hpp>
+
+namespace boost {
+
+namespace units {
+
+namespace detail {
+
+struct solve_end {
+ template<class Begin, class Y>
+ struct apply {
+ typedef dimensionless_type type;
+ };
+};
+
+struct no_solution {};
+
+template<class X1, class X2, class Next>
+struct solve_normal {
+ template<class Begin, class Y>
+ struct apply {
+ typedef typename Begin::next next;
+ typedef list<
+ typename mpl::minus<
+ typename mpl::times<X1, Y>::type,
+ typename mpl::times<X2, typename Begin::item>::type
+ >::type,
+ typename Next::template apply<next, Y>::type
+ > type;
+ };
+};
+
+template<class Next>
+struct solve_leading_zeroes {
+ template<class Begin>
+ struct apply {
+ typedef list<
+ typename Begin::item,
+ typename Next::template apply<typename Begin::next>::type
+ > type;
+ };
+ typedef solve_leading_zeroes type;
+};
+
+template<>
+struct solve_leading_zeroes<no_solution> {
+ typedef no_solution type;
+};
+
+template<class Next>
+struct solve_first_non_zero {
+ template<class Begin>
+ struct apply {
+ typedef typename Next::template apply<
+ typename Begin::next,
+ typename Begin::item
+ >::type type;
+ };
+};
+
+template<class Next>
+struct solve_internal_zero {
+ template<class Begin, class Y>
+ struct apply {
+ typedef list<
+ typename Begin::item,
+ typename Next::template apply<typename Begin::next, Y>::type
+ > type;
+ };
+};
+
+template<class T>
+struct make_solve_list_internal_zero {
+ template<class Next, class X>
+ struct apply {
+ typedef solve_normal<T, X, Next> type;
+ };
+};
+
+template<>
+struct make_solve_list_internal_zero<static_rational<0> > {
+ template<class Next, class X>
+ struct apply {
+ typedef solve_internal_zero<Next> type;
+ };
+};
+
+template<int N>
+struct make_solve_list_normal {
+ template<class Begin, class X>
+ struct apply {
+ typedef typename make_solve_list_internal_zero<
+ typename Begin::item
+ >::template apply<
+ typename make_solve_list_normal<N-1>::template apply<typename Begin::next, X>::type,
+ X
+ >::type type;
+ };
+};
+
+template<>
+struct make_solve_list_normal<0> {
+ template<class Begin, class X>
+ struct apply {
+ typedef solve_end type;
+ };
+};
+
+template<int N>
+struct make_solve_list_leading_zeroes;
+
+template<class T>
+struct make_solve_list_first_non_zero {
+ template<class Begin, int N>
+ struct apply {
+ typedef solve_first_non_zero<
+ typename make_solve_list_normal<N-1>::template apply<
+ typename Begin::next,
+ typename Begin::item
+ >::type
+ > type;
+ };
+};
+
+template<>
+struct make_solve_list_first_non_zero<static_rational<0> > {
+ template<class Begin, int N>
+ struct apply {
+ typedef typename solve_leading_zeroes<
+ typename make_solve_list_leading_zeroes<N-1>::template apply<
+ typename Begin::next
+ >::type
+ >::type type;
+ };
+};
+
+template<int N>
+struct make_solve_list_leading_zeroes {
+ template<class Begin>
+ struct apply {
+ typedef typename make_solve_list_first_non_zero<typename Begin::item>::template apply<Begin, N>::type type;
+ };
+};
+
+template<>
+struct make_solve_list_leading_zeroes<0> {
+ template<class Begin>
+ struct apply {
+ typedef no_solution type;
+ };
+};
+
+template<int N>
+struct try_add_unit_impl {
+ template<class Begin, class L>
+ struct apply {
+ typedef typename try_add_unit_impl<N-1>::template apply<typename Begin::next, L>::type next;
+ typedef typename Begin::item::template apply<next>::type type;
+ BOOST_STATIC_ASSERT((next::size::value - 1 == type::size::value));
+ };
+};
+
+template<>
+struct try_add_unit_impl<0> {
+ template<class Begin, class L>
+ struct apply {
+ typedef L type;
+ };
+};
+
+template<int N>
+struct make_homogeneous_system_impl;
+
+template<class T, bool is_done>
+struct make_homogeneous_system_func;
+
+template<class T>
+struct make_homogeneous_system_func<T, false> {
+ template<class Begin, class Current, class Units, class Dimensions, int N>
+ struct apply {
+ typedef typename make_homogeneous_system_impl<N-1>::template apply<
+ typename Begin::next,
+ list<T, Current>,
+ list<typename Begin::item, Units>,
+ Dimensions
+ >::type type;
+ };
+};
+
+template<class T>
+struct make_homogeneous_system_func<T, true> {
+ template<class Begin, class Current, class Units, class Dimensions, int N>
+ struct apply {
+ typedef list<typename Begin::item, Units> type;
+ };
+};
+
+template<>
+struct make_homogeneous_system_func<no_solution, false> {
+ template<class Begin, class Current, class Units, class Dimensions, int N>
+ struct apply {
+ typedef typename make_homogeneous_system_impl<N-1>::template apply<
+ typename Begin::next,
+ Current,
+ Units,
+ Dimensions
+ >::type type;
+ };
+};
+
+template<>
+struct make_homogeneous_system_func<no_solution, true> {
+ template<class Begin, class Current, class Units, class Dimensions, int N>
+ struct apply {
+ typedef typename make_homogeneous_system_impl<N-1>::template apply<
+ typename Begin::next,
+ Current,
+ Units,
+ Dimensions
+ >::type type;
+ };
+};
+
+template<int N>
+struct make_homogeneous_system_impl {
+ template<class Begin, class Current, class Units, class Dimensions>
+ struct apply {
+ typedef typename expand_dimensions<Dimensions::size::value>::template apply<
+ Dimensions,
+ typename Begin::item::dimension_type
+ >::type dimensions;
+ typedef typename try_add_unit_impl<Current::size::value>::template apply<Current, dimensions>::type new_element;
+ typedef typename make_solve_list_leading_zeroes<new_element::size::value>::template apply<new_element>::type new_func;
+ typedef typename make_homogeneous_system_func<
+ new_func,
+ ((Current::size::value)+1) == (Dimensions::size::value)
+ >::template apply<Begin, Current, Units, Dimensions, N>::type type;
+ };
+};
+
+template<>
+struct make_homogeneous_system_impl<0> {
+ template<class Begin, class Current, class Units, class Dimensions>
+ struct apply {
+ typedef Units type;
+ };
+};
+
+template<class Units>
+struct make_homogeneous_system {
+ typedef typename find_base_dimensions<Units>::type base_dimensions;
+ typedef homogeneous_system<
+ typename insertion_sort<
+ typename make_homogeneous_system_impl<
+ Units::size::value
+ >::template apply<
+ Units,
+ dimensionless_type,
+ dimensionless_type,
+ base_dimensions
+ >::type
+ >::type
+ > type;
+};
+
+template<int N>
+struct extract_base_units {
+ template<class Begin, class T>
+ struct apply {
+ typedef list<
+ typename Begin::item::tag_type,
+ typename extract_base_units<N-1>::template apply<typename Begin::next, T>::type
+ > type;
+ };
+};
+
+template<>
+struct extract_base_units<0> {
+ template<class Begin, class T>
+ struct apply {
+ typedef T type;
+ };
+};
+
+}
+
+}
+
+}
+
+#endif