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167 lines
4.6 KiB
167 lines
4.6 KiB
// Boost.Units - A C++ library for zero-overhead dimensional analysis and |
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// unit/quantity manipulation and conversion |
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// |
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// Copyright (C) 2003-2008 Matthias Christian Schabel |
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// Copyright (C) 2007-2008 Steven Watanabe |
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// |
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// Distributed under the Boost Software License, Version 1.0. (See |
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// accompanying file LICENSE_1_0.txt or copy at |
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// http://www.boost.org/LICENSE_1_0.txt) |
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#ifndef BOOST_UNITS_DIM_HPP |
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#define BOOST_UNITS_DIM_HPP |
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#include <boost/static_assert.hpp> |
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#include <boost/type_traits/is_same.hpp> |
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#include <boost/mpl/arithmetic.hpp> |
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#include <boost/units/config.hpp> |
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#include <boost/units/static_rational.hpp> |
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#include <boost/units/detail/dim_impl.hpp> |
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/// \file dim.hpp |
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/// \brief Handling of fundamental dimension/exponent pairs. |
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namespace boost { |
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namespace units { |
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namespace detail { |
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struct dim_tag { }; |
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} |
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/// \brief Dimension tag/exponent pair for a single fundamental dimension. |
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/// |
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/// \details |
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/// The dim class represents a single dimension tag/dimension exponent pair. |
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/// That is, @c dim<tag_type,value_type> is a pair where @c tag_type represents the |
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/// fundamental dimension being represented and @c value_type represents the |
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/// exponent of that fundamental dimension as a @c static_rational. @c tag_type must |
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/// be a derived from a specialization of @c base_dimension. |
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/// Specialization of the following Boost.MPL metafunctions are provided |
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/// |
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/// - @c mpl::plus for two @c dims |
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/// - @c mpl::minus for two @c dims |
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/// - @c mpl::negate for a @c dim |
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/// |
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/// These metafunctions all operate on the exponent, and require |
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/// that the @c dim operands have the same base dimension tag. |
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/// In addition, multiplication and division by @c static_rational |
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/// is supported. |
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/// |
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/// - @c mpl::times for a @c static_rational and a @c dim in either order |
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/// - @c mpl::divides for a @c static_rational and a @c dim in either order |
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/// |
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/// These metafunctions likewise operate on the exponent only. |
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template<typename T,typename V> |
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struct dim |
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{ |
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typedef dim type; |
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typedef detail::dim_tag tag; |
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typedef T tag_type; |
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typedef V value_type; |
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}; |
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} // namespace units |
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} // namespace boost |
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#if BOOST_UNITS_HAS_BOOST_TYPEOF |
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#include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP() |
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BOOST_TYPEOF_REGISTER_TEMPLATE(boost::units::dim, 2) |
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#endif |
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#ifndef BOOST_UNITS_DOXYGEN |
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namespace boost { |
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namespace mpl { |
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// define MPL operators acting on dim<T,V> |
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template<> |
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struct plus_impl<boost::units::detail::dim_tag,boost::units::detail::dim_tag> |
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{ |
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template<class T0, class T1> |
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struct apply |
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{ |
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BOOST_STATIC_ASSERT((boost::is_same<typename T0::tag_type,typename T1::tag_type>::value == true)); |
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typedef boost::units::dim<typename T0::tag_type, typename mpl::plus<typename T0::value_type, typename T1::value_type>::type> type; |
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}; |
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}; |
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template<> |
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struct minus_impl<boost::units::detail::dim_tag,boost::units::detail::dim_tag> |
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{ |
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template<class T0, class T1> |
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struct apply |
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{ |
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BOOST_STATIC_ASSERT((boost::is_same<typename T0::tag_type,typename T1::tag_type>::value == true)); |
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typedef boost::units::dim<typename T0::tag_type, typename mpl::minus<typename T0::value_type, typename T1::value_type>::type> type; |
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}; |
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}; |
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template<> |
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struct times_impl<boost::units::detail::dim_tag,boost::units::detail::static_rational_tag> |
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{ |
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template<class T0, class T1> |
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struct apply |
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{ |
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typedef boost::units::dim<typename T0::tag_type, typename mpl::times<typename T0::value_type, T1>::type> type; |
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}; |
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}; |
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template<> |
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struct times_impl<boost::units::detail::static_rational_tag,boost::units::detail::dim_tag> |
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{ |
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template<class T0, class T1> |
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struct apply |
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{ |
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typedef boost::units::dim<typename T1::tag_type, typename mpl::times<T0, typename T1::value_type>::type> type; |
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}; |
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}; |
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template<> |
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struct divides_impl<boost::units::detail::dim_tag,boost::units::detail::static_rational_tag> |
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{ |
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template<class T0, class T1> |
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struct apply |
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{ |
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typedef boost::units::dim<typename T0::tag_type, typename mpl::divides<typename T0::value_type, T1>::type> type; |
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}; |
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}; |
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template<> |
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struct divides_impl<boost::units::detail::static_rational_tag,boost::units::detail::dim_tag> |
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{ |
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template<class T0, class T1> |
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struct apply |
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{ |
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typedef boost::units::dim<typename T1::tag_type, typename mpl::divides<T0, typename T1::value_type>::type> type; |
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}; |
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}; |
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template<> |
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struct negate_impl<boost::units::detail::dim_tag> |
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{ |
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template<class T0> |
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struct apply |
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{ |
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typedef boost::units::dim<typename T0::tag_type,typename mpl::negate<typename T0::value_type>::type> type; |
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}; |
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}; |
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} // namespace mpl |
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} // namespace boost |
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#endif |
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#endif // BOOST_UNITS_DIM_HPP
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