Chris@16: // Boost.Units - A C++ library for zero-overhead dimensional analysis and 
Chris@16: // unit/quantity manipulation and conversion
Chris@16: //
Chris@16: // Copyright (C) 2003-2008 Matthias Christian Schabel
Chris@16: // Copyright (C) 2007-2008 Steven Watanabe
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_UNITS_DETAIL_DIMENSIONLESS_UNIT_HPP
Chris@16: #define BOOST_UNITS_DETAIL_DIMENSIONLESS_UNIT_HPP
Chris@16: 
Chris@16: #include <boost/mpl/bool.hpp>
Chris@16: #include <boost/units/units_fwd.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace units {
Chris@16: 
Chris@16: template<class T>
Chris@16: struct heterogeneous_system;
Chris@16: 
Chris@16: template<class T>
Chris@16: struct homogeneous_system;
Chris@16: 
Chris@16: template<class T1, class T2, class Scale>
Chris@16: struct heterogeneous_system_impl;
Chris@16: 
Chris@16: typedef boost::units::heterogeneous_system<
Chris@16:     boost::units::heterogeneous_system_impl<
Chris@16:         boost::units::dimensionless_type,
Chris@16:         boost::units::dimensionless_type,
Chris@16:         boost::units::dimensionless_type
Chris@16:     >
Chris@16: > heterogeneous_dimensionless_system;
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: template<class System>
Chris@16: struct void_if_dimensionless {
Chris@16:     typedef int type;
Chris@16: };
Chris@16: 
Chris@16: template<class T>
Chris@16: struct void_if_dimensionless<boost::units::homogeneous_system<T> > {
Chris@16:     typedef void type;
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct void_if_dimensionless<heterogeneous_dimensionless_system> {
Chris@16:     typedef void type;
Chris@16: };
Chris@16: 
Chris@16: template<class System, class Test = void>
Chris@16: struct void_if_heterogeneous {
Chris@16:     typedef void type;
Chris@16: };
Chris@16: 
Chris@16: template<class System>
Chris@16: struct void_if_heterogeneous<System, typename void_if_dimensionless<System>::type> {
Chris@16:     typedef int type;
Chris@16: };
Chris@16: 
Chris@16: template<class System, class Enable=void>
Chris@16: struct is_dimensionless_system : mpl::false_ {};
Chris@16: 
Chris@16: template<class System>
Chris@16: struct is_dimensionless_system<System, typename void_if_dimensionless<System>::type> : mpl::true_ {};
Chris@16: 
Chris@16: #define BOOST_UNITS_DIMENSIONLESS_UNIT(T)\
Chris@16:     boost::units::unit<\
Chris@16:         boost::units::dimensionless_type,\
Chris@16:         T,\
Chris@16:         typename ::boost::units::detail::void_if_dimensionless<T>::type\
Chris@16:     >
Chris@16: 
Chris@16: #define BOOST_UNITS_HETEROGENEOUS_DIMENSIONLESS_UNIT(T)\
Chris@16:     boost::units::unit<\
Chris@16:         boost::units::dimensionless_type,\
Chris@16:         T,\
Chris@16:         typename ::boost::units::detail::void_if_heterogeneous<T>::type\
Chris@16:     >
Chris@16: 
Chris@16: }
Chris@16: }
Chris@16: }
Chris@16: 
Chris@16: #endif