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			4.8 KiB
		
	
	
	
		
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			168 lines
		
	
	
		
			4.8 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
| // 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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| 
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| #ifndef BOOST_UNITS_DIM_HPP
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| #define BOOST_UNITS_DIM_HPP
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| 
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| #include <boost/static_assert.hpp>
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| 
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| #include <boost/type_traits/is_same.hpp>
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| 
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| #include <boost/mpl/arithmetic.hpp>
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| 
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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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| 
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| /// \file dim.hpp
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| /// \brief Handling of fundamental dimension/exponent pairs.
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| 
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| namespace boost {
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| 
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| namespace units {
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| 
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| namespace detail {
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| 
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| struct dim_tag { };
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| 
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| }
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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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| 
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| } // namespace units
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| 
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| } // namespace boost
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| 
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| #if BOOST_UNITS_HAS_BOOST_TYPEOF
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| 
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| #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP()
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| 
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| BOOST_TYPEOF_REGISTER_TEMPLATE(boost::units::dim, 2)
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| 
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| #endif
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| 
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| #ifndef BOOST_UNITS_DOXYGEN
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| 
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| namespace boost {
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| 
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| namespace mpl {
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| 
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| // define MPL operators acting on dim<T,V>
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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| } // namespace mpl
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| 
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| } // namespace boost
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| 
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| #endif
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| 
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| #endif // BOOST_UNITS_DIM_HPP
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