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_HOMOGENEOUS_SYSTEM_HPP_INCLUDED 12 #define BOOST_UNITS_HOMOGENEOUS_SYSTEM_HPP_INCLUDED 13 14 #include <boost/mpl/bool.hpp> 15 16 #include <boost/units/config.hpp> 17 #include <boost/units/static_rational.hpp> 18 19 #ifdef BOOST_UNITS_CHECK_HOMOGENEOUS_UNITS 20 21 #include <boost/type_traits/is_same.hpp> 22 #include <boost/mpl/not.hpp> 23 24 #include <boost/units/detail/linear_algebra.hpp> 25 26 #endif 27 28 namespace boost { 29 30 namespace units { 31 32 /// A system that can uniquely represent any unit 33 /// which can be composed from a linearly independent set 34 /// of base units. It is safe to rebind a unit with 35 /// such a system to different dimensions. 36 /// 37 /// Do not construct this template directly. Use 38 /// make_system instead. 39 template<class L> 40 struct homogeneous_system { 41 /// INTERNAL ONLY 42 typedef L type; 43 }; 44 45 template<class T, class E> 46 struct static_power; 47 48 template<class T, class R> 49 struct static_root; 50 51 /// INTERNAL ONLY 52 template<class L, long N, long D> 53 struct static_power<homogeneous_system<L>, static_rational<N,D> > 54 { 55 typedef homogeneous_system<L> type; 56 }; 57 58 /// INTERNAL ONLY 59 template<class L, long N, long D> 60 struct static_root<homogeneous_system<L>, static_rational<N,D> > 61 { 62 typedef homogeneous_system<L> type; 63 }; 64 65 namespace detail { 66 67 template<class System, class Dimensions> 68 struct check_system; 69 70 #ifdef BOOST_UNITS_CHECK_HOMOGENEOUS_UNITS 71 72 template<class L, class Dimensions> 73 struct check_system<homogeneous_system<L>, Dimensions> : 74 boost::mpl::not_< 75 boost::is_same< 76 typename calculate_base_unit_exponents< 77 L, 78 Dimensions 79 >::type, 80 inconsistent 81 > 82 > {}; 83 84 #else 85 86 template<class L, class Dimensions> 87 struct check_system<homogeneous_system<L>, Dimensions> : mpl::true_ {}; 88 89 #endif 90 91 } // namespace detail 92 93 } // namespace units 94 95 } // namespace boost 96 97 #if BOOST_UNITS_HAS_BOOST_TYPEOF 98 99 #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP() 100 101 BOOST_TYPEOF_REGISTER_TEMPLATE(boost::units::homogeneous_system, (class)) 102 103 #endif 104 105 #endif 106