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_STATIC_RATIONAL_POWER_HPP
Chris@16: #define BOOST_UNITS_DETAIL_STATIC_RATIONAL_POWER_HPP
Chris@16: 
Chris@16: #include <boost/config/no_tr1/cmath.hpp>
Chris@16: 
Chris@16: #include <boost/units/detail/one.hpp>
Chris@16: #include <boost/units/operators.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: namespace units {
Chris@16: 
Chris@16: template<long N,long D>
Chris@16: class static_rational;
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: namespace typeof_pow_adl_barrier {
Chris@16: 
Chris@16: using std::pow;
Chris@16: 
Chris@16: template<class Y>
Chris@16: struct typeof_pow
Chris@16: {
Chris@16: #if defined(BOOST_UNITS_HAS_BOOST_TYPEOF)
Chris@16:     BOOST_TYPEOF_NESTED_TYPEDEF_TPL(nested, pow(typeof_::make<Y>(), 0.0))
Chris@16:     typedef typename nested::type type;
Chris@16: #elif defined(BOOST_UNITS_HAS_MWERKS_TYPEOF)
Chris@16:     typedef __typeof__(pow(typeof_::make<Y>(), 0.0)) type;
Chris@16: #elif defined(BOOST_UNITS_HAS_GNU_TYPEOF)
Chris@16:     typedef typeof(pow(typeof_::make<Y>(), 0.0)) type;
Chris@16: #else
Chris@16:     typedef Y type;
Chris@16: #endif
Chris@16: };
Chris@16: 
Chris@16: }
Chris@16: 
Chris@16: template<class R, class Y>
Chris@16: struct static_rational_power_impl
Chris@16: {
Chris@16:     typedef typename typeof_pow_adl_barrier::typeof_pow<Y>::type type;
Chris@16:     static type call(const Y& y)
Chris@16:     {
Chris@16:         using std::pow;
Chris@16:         return(pow(y, static_cast<double>(R::Numerator) / static_cast<double>(R::Denominator)));
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template<class R>
Chris@16: struct static_rational_power_impl<R, one>
Chris@16: {
Chris@16:     typedef one type;
Chris@16:     static one call(const one&)
Chris@16:     {
Chris@16:         one result;
Chris@16:         return(result);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template<long N>
Chris@16: struct static_rational_power_impl<static_rational<N, 1>, one>
Chris@16: {
Chris@16:     typedef one type;
Chris@16:     static one call(const one&)
Chris@16:     {
Chris@16:         one result;
Chris@16:         return(result);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template<long N, bool = (N % 2 == 0)>
Chris@16: struct static_int_power_impl;
Chris@16: 
Chris@16: template<long N>
Chris@16: struct static_int_power_impl<N, true>
Chris@16: {
Chris@16:     template<class Y, class R>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef typename multiply_typeof_helper<Y, Y>::type square_type;
Chris@16:         typedef typename static_int_power_impl<(N >> 1)>::template apply<square_type, R> next;
Chris@16:         typedef typename next::type type;
Chris@16:         static type call(const Y& y, const R& r)
Chris@16:         {
Chris@16:             const square_type square = y * y;
Chris@16:             return(next::call(square, r));
Chris@16:         }
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<long N>
Chris@16: struct static_int_power_impl<N, false>
Chris@16: {
Chris@16:     template<class Y, class R>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef typename multiply_typeof_helper<Y, Y>::type square_type;
Chris@16:         typedef typename multiply_typeof_helper<Y, R>::type new_r;
Chris@16:         typedef typename static_int_power_impl<(N >> 1)>::template apply<square_type, new_r> next;
Chris@16:         typedef typename next::type type;
Chris@16:         static type call(const Y& y, const R& r)
Chris@16:         {
Chris@16:             const Y square = y * y;
Chris@16:             return(next::call(square, y * r));
Chris@16:         }
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct static_int_power_impl<1, false>
Chris@16: {
Chris@16:     template<class Y, class R>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef typename multiply_typeof_helper<Y, R>::type type;
Chris@16:         static type call(const Y& y, const R& r)
Chris@16:         {
Chris@16:             return(y * r);
Chris@16:         }
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct static_int_power_impl<0, true>
Chris@16: {
Chris@16:     template<class Y, class R>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef R type;
Chris@16:         static R call(const Y&, const R& r)
Chris@16:         {
Chris@16:             return(r);
Chris@16:         }
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<int N, bool = (N < 0)>
Chris@16: struct static_int_power_sign_impl;
Chris@16: 
Chris@16: template<int N>
Chris@16: struct static_int_power_sign_impl<N, false>
Chris@16: {
Chris@16:     template<class Y>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef typename static_int_power_impl<N>::template apply<Y, one> impl;
Chris@16:         typedef typename impl::type type;
Chris@16:         static type call(const Y& y)
Chris@16:         {
Chris@16:             one result;
Chris@16:             return(impl::call(y, result));
Chris@16:         }
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<int N>
Chris@16: struct static_int_power_sign_impl<N, true>
Chris@16: {
Chris@16:     template<class Y>
Chris@16:     struct apply
Chris@16:     {
Chris@16:         typedef typename static_int_power_impl<-N>::template apply<Y, one> impl;
Chris@16:         typedef typename divide_typeof_helper<one, typename impl::type>::type type;
Chris@16:         static type call(const Y& y)
Chris@16:         {
Chris@16:             one result;
Chris@16:             return(result/impl::call(y, result));
Chris@16:         }
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<long N, class Y>
Chris@16: struct static_rational_power_impl<static_rational<N, 1>, Y>
Chris@16: {
Chris@16:     typedef typename static_int_power_sign_impl<N>::template apply<Y> impl;
Chris@16:     typedef typename impl::type type;
Chris@16:     static type call(const Y& y)
Chris@16:     {
Chris@16:         return(impl::call(y));
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template<class R, class Y>
Chris@16: typename detail::static_rational_power_impl<R, Y>::type static_rational_power(const Y& y)
Chris@16: {
Chris@16:     return(detail::static_rational_power_impl<R, Y>::call(y));
Chris@16: }
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: } // namespace units
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif