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) 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_STATIC_RATIONAL_HPP 
Chris@16: #define BOOST_UNITS_STATIC_RATIONAL_HPP
Chris@16: 
Chris@101: #include <boost/integer/common_factor_ct.hpp>
Chris@16: #include <boost/mpl/less.hpp>
Chris@16: #include <boost/mpl/arithmetic.hpp>
Chris@16: 
Chris@16: #ifdef __BORLANDC__
Chris@16: #include <boost/mpl/eval_if.hpp>
Chris@16: #include <boost/mpl/integral_c.hpp>
Chris@16: #include <boost/mpl/identity.hpp>
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/units/config.hpp>
Chris@16: #include <boost/units/operators.hpp>
Chris@16: 
Chris@16: /// \file 
Chris@16: /// \brief Compile-time rational numbers and operators.
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: namespace units { 
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: struct static_rational_tag {};
Chris@16: 
Chris@16: }
Chris@16: 
Chris@16: typedef long   integer_type;
Chris@16: 
Chris@16: /// Compile time absolute value.
Chris@16: template<integer_type Value>
Chris@16: struct static_abs
Chris@16: {
Chris@16:     BOOST_STATIC_CONSTANT(integer_type,value = Value < 0 ? -Value : Value);
Chris@16: };
Chris@16: 
Chris@16: // Compile time rational number.
Chris@16: /** 
Chris@16: This is an implementation of a compile time rational number, where @c static_rational<N,D> represents
Chris@16: a rational number with numerator @c N and denominator @c D. Because of the potential for ambiguity arising 
Chris@16: from multiple equivalent values of @c static_rational (e.g. @c static_rational<6,2>==static_rational<3>), 
Chris@16: static rationals should always be accessed through @c static_rational<N,D>::type. Template specialization 
Chris@16: prevents instantiation of zero denominators (i.e. @c static_rational<N,0>). The following compile-time 
Chris@16: arithmetic operators are provided for static_rational variables only (no operators are defined between 
Chris@16: long and static_rational):
Chris@16:     - @c mpl::negate
Chris@16:     - @c mpl::plus
Chris@16:     - @c mpl::minus
Chris@16:     - @c mpl::times
Chris@16:     - @c mpl::divides
Chris@16: 
Chris@16: Neither @c static_power nor @c static_root are defined for @c static_rational. This is because template types 
Chris@16: may not be floating point values, while powers and roots of rational numbers can produce floating point 
Chris@16: values. 
Chris@16: */
Chris@16: #ifdef __BORLANDC__
Chris@16: 
Chris@16: template<integer_type X>
Chris@16: struct make_integral_c {
Chris@16:     typedef boost::mpl::integral_c<integer_type, X> type;
Chris@16: };
Chris@16: 
Chris@16: template<integer_type N,integer_type D = 1>
Chris@16: class static_rational
Chris@16: {
Chris@16:     public:
Chris@16: 
Chris@16:         typedef static_rational this_type;
Chris@16: 
Chris@16:         typedef boost::mpl::integral_c<integer_type, N> N_type;
Chris@16:         typedef boost::mpl::integral_c<integer_type, D> D_type;
Chris@16: 
Chris@16:         typedef typename make_integral_c<
Chris@101:             (::boost::integer::static_gcd<
Chris@16:                 ::boost::units::static_abs<N>::value,
Chris@16:                 ::boost::units::static_abs<D>::value
Chris@16:             >::value)>::type gcd_type;
Chris@16:         typedef typename boost::mpl::eval_if<
Chris@16:             boost::mpl::less<
Chris@16:                 D_type,
Chris@16:                 boost::mpl::integral_c<integer_type, 0>
Chris@16:             >,
Chris@16:             boost::mpl::negate<gcd_type>,
Chris@16:             gcd_type
Chris@16:         >::type den_type;
Chris@16:         
Chris@16:     public: 
Chris@16:         // for mpl arithmetic support
Chris@16:         typedef detail::static_rational_tag tag;
Chris@16:         
Chris@16:         BOOST_STATIC_CONSTANT(integer_type, Numerator =
Chris@16:             (::boost::mpl::divides<N_type, den_type>::value));
Chris@16:         BOOST_STATIC_CONSTANT(integer_type, Denominator =
Chris@16:             (::boost::mpl::divides<D_type, den_type>::value));
Chris@16:         
Chris@16:         /// INTERNAL ONLY
Chris@16:         typedef static_rational<N,D>    this_type;
Chris@16:         
Chris@16:         /// static_rational<N,D> reduced by GCD
Chris@16:         typedef static_rational<
Chris@16:             (::boost::mpl::divides<N_type, den_type>::value),
Chris@16:             (::boost::mpl::divides<D_type, den_type>::value)
Chris@16:         >  type;
Chris@16:                                  
Chris@16:         static integer_type numerator()      { return Numerator; }
Chris@16:         static integer_type denominator()    { return Denominator; }
Chris@16:         
Chris@16:         // INTERNAL ONLY
Chris@16:         static_rational() { }
Chris@16:         //~static_rational() { }
Chris@16: };
Chris@16: #else
Chris@16: template<integer_type N,integer_type D = 1>
Chris@16: class static_rational
Chris@16: {
Chris@16:     private:
Chris@16: 
Chris@16:         static const integer_type   nabs = static_abs<N>::value,
Chris@16:                                     dabs = static_abs<D>::value;
Chris@16:         
Chris@16:         /// greatest common divisor of N and D
Chris@16:         // need cast to signed because static_gcd returns unsigned long
Chris@16:         static const integer_type   den = 
Chris@101:             static_cast<integer_type>(boost::integer::static_gcd<nabs,dabs>::value) * ((D < 0) ? -1 : 1);
Chris@16:         
Chris@16:     public: 
Chris@16:         // for mpl arithmetic support
Chris@16:         typedef detail::static_rational_tag tag;
Chris@16:         
Chris@16:         static const integer_type   Numerator = N/den,
Chris@16:             Denominator = D/den;
Chris@16:         
Chris@16:         /// INTERNAL ONLY
Chris@16:         typedef static_rational<N,D>    this_type;
Chris@16:         
Chris@16:         /// static_rational<N,D> reduced by GCD
Chris@16:         typedef static_rational<Numerator,Denominator>  type;
Chris@16:                                  
Chris@16:         static integer_type numerator()      { return Numerator; }
Chris@16:         static integer_type denominator()    { return Denominator; }
Chris@16:         
Chris@16:         // INTERNAL ONLY
Chris@16:         static_rational() { }
Chris@16:         //~static_rational() { }   
Chris@16: };
Chris@16: #endif
Chris@16: 
Chris@16: }
Chris@16: 
Chris@16: }
Chris@16: 
Chris@16: #if BOOST_UNITS_HAS_BOOST_TYPEOF
Chris@16: 
Chris@16: #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP()
Chris@16: 
Chris@16: BOOST_TYPEOF_REGISTER_TEMPLATE(boost::units::static_rational, (long)(long))
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: namespace units {
Chris@16: 
Chris@16: // prohibit zero denominator
Chris@16: template<integer_type N> class static_rational<N,0>;
Chris@16: 
Chris@16: /// get decimal value of @c static_rational
Chris@16: template<class T,integer_type N,integer_type D>
Chris@16: inline typename divide_typeof_helper<T,T>::type 
Chris@16: value(const static_rational<N,D>&)
Chris@16: {
Chris@16:     return T(N)/T(D);
Chris@16: }
Chris@16: 
Chris@16: } // namespace units
Chris@16: 
Chris@16: #ifndef BOOST_UNITS_DOXYGEN
Chris@16: 
Chris@16: namespace mpl {
Chris@16: 
Chris@16: #ifdef __BORLANDC__
Chris@16: 
Chris@16: template<>
Chris@16: struct plus_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply {
Chris@16:         typedef typename boost::units::static_rational<
Chris@16:             ::boost::mpl::plus<
Chris@16:                 boost::mpl::times<typename T0::N_type, typename T1::D_type>,
Chris@16:                 boost::mpl::times<typename T1::N_type, typename T0::D_type>
Chris@16:             >::value,
Chris@16:             ::boost::mpl::times<typename T0::D_type, typename T1::D_type>::value
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct minus_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply {
Chris@16:         typedef typename boost::units::static_rational<
Chris@16:             ::boost::mpl::minus<
Chris@16:                 boost::mpl::times<typename T0::N_type, typename T1::D_type>,
Chris@16:                 boost::mpl::times<typename T1::N_type, typename T0::D_type>
Chris@16:             >::value,
Chris@16:             ::boost::mpl::times<typename T0::D_type, typename T1::D_type>::value
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct times_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply {
Chris@16:         typedef typename boost::units::static_rational<
Chris@16:             ::boost::mpl::times<typename T0::N_type, typename T1::N_type>::value,
Chris@16:             ::boost::mpl::times<typename T0::D_type, typename T1::D_type>::value
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct divides_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply {
Chris@16:         typedef typename boost::units::static_rational<
Chris@16:             ::boost::mpl::times<typename T0::N_type, typename T1::D_type>::value,
Chris@16:             ::boost::mpl::times<typename T0::D_type, typename T1::N_type>::value
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct negate_impl<boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0>
Chris@16:     struct apply {
Chris@16:         typedef typename boost::units::static_rational<
Chris@16:             ::boost::mpl::negate<typename T0::N_type>::value,
Chris@16:             ::boost::mpl::identity<T0>::type::Denominator
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct less_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef mpl::bool_<((mpl::minus<T0, T1>::type::Numerator) < 0)> type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16: template<>
Chris@16: struct plus_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply {
Chris@16:         typedef typename boost::units::static_rational<
Chris@16:             T0::Numerator*T1::Denominator+T1::Numerator*T0::Denominator,
Chris@16:             T0::Denominator*T1::Denominator
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct minus_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply {
Chris@16:         typedef typename boost::units::static_rational<
Chris@16:             T0::Numerator*T1::Denominator-T1::Numerator*T0::Denominator,
Chris@16:             T0::Denominator*T1::Denominator
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct times_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply {
Chris@16:         typedef typename boost::units::static_rational<
Chris@16:             T0::Numerator*T1::Numerator,
Chris@16:             T0::Denominator*T1::Denominator
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct divides_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply {
Chris@16:         typedef typename boost::units::static_rational<
Chris@16:             T0::Numerator*T1::Denominator,
Chris@16:             T0::Denominator*T1::Numerator
Chris@16:         >::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct negate_impl<boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0>
Chris@16:     struct apply {
Chris@16:         typedef typename boost::units::static_rational<-T0::Numerator,T0::Denominator>::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct less_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag>
Chris@16: {
Chris@16:     template<class T0, class T1>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef mpl::bool_<((mpl::minus<T0, T1>::type::Numerator) < 0)> type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: 
Chris@16: }
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif // BOOST_UNITS_STATIC_RATIONAL_HPP