1 // Boost.Units - A C++ library for zero-overhead dimensional analysis and 2 // unit/quantity manipulation and conversion 3 // 4 // Copyright (C) 2003-2008 Matthias Christian Schabel 5 // Copyright (C) 2008 Steven Watanabe 6 // 7 // Distributed under the Boost Software License, Version 1.0. (See 8 // accompanying file LICENSE_1_0.txt or copy at 9 // http://www.boost.org/LICENSE_1_0.txt) 10 11 #ifndef BOOST_UNITS_ABSOLUTE_IMPL_HPP 12 #define BOOST_UNITS_ABSOLUTE_IMPL_HPP 13 14 #include <iosfwd> 15 16 #include <boost/units/config.hpp> 17 #include <boost/units/conversion.hpp> 18 #include <boost/units/heterogeneous_system.hpp> 19 #include <boost/units/units_fwd.hpp> 20 21 namespace boost { 22 23 namespace units { 24 25 /// INTERNAL ONLY 26 template<class D, class S> 27 struct reduce_unit<absolute<unit<D, S> > > 28 { 29 typedef absolute<typename reduce_unit<unit<D, S> >::type> type; 30 }; 31 32 namespace detail { 33 34 struct undefined_affine_conversion_base { 35 static const bool is_defined = false; 36 }; 37 38 } // namespace detail 39 40 /// INTERNAL ONLY 41 template<class From, class To> 42 struct affine_conversion_helper : detail::undefined_affine_conversion_base { }; 43 44 namespace detail { 45 46 template<bool IsDefined, bool ReverseIsDefined> 47 struct affine_conversion_impl; 48 49 template<bool ReverseIsDefined> 50 struct affine_conversion_impl<true, ReverseIsDefined> 51 { 52 template<class Unit1, class Unit2, class T0, class T1> 53 struct apply { valueboost::units::detail::affine_conversion_impl::apply54 static T1 value(const T0& t0) 55 { 56 return( 57 t0 * 58 conversion_factor(Unit1(), Unit2()) + 59 affine_conversion_helper<typename reduce_unit<Unit1>::type, typename reduce_unit<Unit2>::type>::value()); 60 } 61 }; 62 }; 63 64 template<> 65 struct affine_conversion_impl<false, true> 66 { 67 template<class Unit1, class Unit2, class T0, class T1> 68 struct apply 69 { valueboost::units::detail::affine_conversion_impl::apply70 static T1 value(const T0& t0) 71 { 72 return( 73 (t0 - affine_conversion_helper<typename reduce_unit<Unit2>::type, typename reduce_unit<Unit1>::type>::value()) * 74 conversion_factor(Unit1(), Unit2())); 75 } 76 }; 77 }; 78 79 } // namespace detail 80 81 /// INTERNAL ONLY 82 template<class Unit1, class T1, class Unit2, class T2> 83 struct conversion_helper<quantity<absolute<Unit1>, T1>, quantity<absolute<Unit2>, T2> > 84 { 85 typedef quantity<absolute<Unit1>, T1> from_quantity_type; 86 typedef quantity<absolute<Unit2>, T2> to_quantity_type; convertboost::units::conversion_helper87 static to_quantity_type convert(const from_quantity_type& source) 88 { 89 return( 90 to_quantity_type::from_value( 91 detail::affine_conversion_impl< 92 affine_conversion_helper<typename reduce_unit<Unit1>::type, typename reduce_unit<Unit2>::type>::is_defined, 93 affine_conversion_helper<typename reduce_unit<Unit2>::type, typename reduce_unit<Unit1>::type>::is_defined 94 >::template apply<Unit1, Unit2, T1, T2>::value(source.value()) 95 ) 96 ); 97 } 98 }; 99 100 } // namespace units 101 102 } // namespace boost 103 104 #endif // BOOST_UNITS_ABSOLUTE_IMPL_HPP 105