Chris@16: ////////////////////////////////////////////////////////////////////
Chris@16: //
Chris@16: // Copyright Vicente J. Botet Escriba 2010
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0.
Chris@16: // (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/mpl for documentation.
Chris@16: //
Chris@16: ////////////////////////////////////////////////////////////////////
Chris@16: #ifndef BOOST_MPL_GCD_HPP_INCLUDED
Chris@16: #define BOOST_MPL_GCD_HPP_INCLUDED
Chris@16: 
Chris@16: #include <boost/mpl/integral_c.hpp>
Chris@16: #include <boost/ratio/detail/mpl/abs.hpp>
Chris@16: #include <boost/mpl/aux_/largest_int.hpp>
Chris@16: #include <boost/mpl/aux_/na_spec.hpp>
Chris@16: #include <boost/mpl/aux_/lambda_support.hpp>
Chris@16: #include <boost/mpl/aux_/config/integral.hpp>
Chris@16: #include <boost/mpl/aux_/config/static_constant.hpp>
Chris@16: #include <boost/mpl/aux_/config/dependent_nttp.hpp>
Chris@16: #include <boost/cstdint.hpp>
Chris@16: 
Chris@16: #if    !defined(BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2) \
Chris@16:     && !defined(BOOST_MPL_PREPROCESSING_MODE) \
Chris@101:     && !defined(__CUDACC__) \
Chris@16:     && ( defined(BOOST_MSVC) \
Chris@16:         || BOOST_WORKAROUND(__EDG_VERSION__, <= 238) \
Chris@16:         )
Chris@16: 
Chris@16: #   define BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost { namespace mpl {
Chris@16: 
Chris@16: template< typename Tag1, typename Tag2 > struct gcd_impl;
Chris@16: 
Chris@16: template< typename T > struct gcd_tag
Chris@16: {
Chris@16:     typedef typename T::tag type;
Chris@16: };
Chris@16: 
Chris@16: template<
Chris@16:       typename BOOST_MPL_AUX_NA_PARAM(N1)
Chris@16:     , typename BOOST_MPL_AUX_NA_PARAM(N2)
Chris@16:     >
Chris@16: struct gcd
Chris@16:     : gcd_impl<
Chris@16:           typename gcd_tag<N1>::type
Chris@16:         , typename gcd_tag<N2>::type
Chris@16:         >::template apply<N1, N2>::type
Chris@16: {
Chris@16:     BOOST_MPL_AUX_LAMBDA_SUPPORT(2, gcd, (N1, N2))
Chris@16: };
Chris@16: 
Chris@16: BOOST_MPL_AUX_NA_SPEC(2, gcd)
Chris@16: 
Chris@16: template<
Chris@16:       typename T
Chris@16:     , T n1
Chris@16:     , T n2
Chris@16:     >
Chris@16: struct gcd_c
Chris@16:     : gcd<integral_c<T,n1>,integral_c<T,n2> >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: namespace aux {
Chris@16: 
Chris@16:   // Workaround for error: the type of partial specialization template parameter constant "n2"
Chris@16:     // depends on another template parameter
Chris@16:     // Note: this solution could be wrong for n1 or n2 = [2**63 .. 2**64-1]
Chris@16: #if defined(BOOST_MPL_CFG_NO_DEPENDENT_NONTYPE_PARAMETER_IN_PARTIAL_SPEC)
Chris@16: 
Chris@16:   template< typename T1, boost::intmax_t n1, bool n1_is_0
Chris@16:                   , typename T2, boost::intmax_t n2, bool n2_is_0 >
Chris@16:       struct gcd_aux
Chris@16:           : gcd_aux<T2, n2, n2==0, T1, (n1 % n2), (n1 % n2)==0>
Chris@16:       {};
Chris@16: 
Chris@16:       template <typename T1, boost::intmax_t n1, typename T2, boost::intmax_t n2>
Chris@16:       struct gcd_aux<T1, n1, false, T2, n2, true> : integral_c<T1, n1>
Chris@16:       {};
Chris@16: 
Chris@16:       template <typename T1, boost::intmax_t n1, typename T2, boost::intmax_t n2, bool C>
Chris@16:       struct gcd_aux<T1, n1, true, T2, n2, C> : integral_c<T2, n2>
Chris@16:       {};
Chris@16: 
Chris@16: #else // defined(BOOST_MPL_CFG_NO_DEPENDENT_NONTYPE_PARAMETER_IN_PARTIAL_SPEC)
Chris@16: 
Chris@16:     template< typename T1, T1 n1, bool n1_is_0, typename T2, T2 n2, bool n2_is_0 >
Chris@16:     struct gcd_aux
Chris@16: 
Chris@16:         : gcd_aux<T2, n2, n2==0,
Chris@16:                     typename aux::largest_int<T1, T2>::type,
Chris@16:                     //~ T1,
Chris@16:                     (n1 % n2), (n1 % n2)==0>
Chris@16:     {};
Chris@16: 
Chris@16:     template <typename T1, T1 n1, typename T2, T2 n2>
Chris@16:     struct gcd_aux<T1, n1, false, T2, n2, true> : integral_c<T1, n1>
Chris@16:     {};
Chris@16: 
Chris@16:     template <typename T1, T1 n1, typename T2, T2 n2, bool C>
Chris@16:     struct gcd_aux<T1, n1, true, T2, n2, C> : integral_c<T2, n2>
Chris@16:     {};
Chris@16: #endif // defined(BOOST_MPL_CFG_NO_DEPENDENT_NONTYPE_PARAMETER_IN_PARTIAL_SPEC)
Chris@16: }
Chris@16: 
Chris@16: template<>
Chris@16: struct gcd_impl<integral_c_tag, integral_c_tag>
Chris@16: {
Chris@16:     template< typename N1, typename N2 > struct apply
Chris@16:         : abs<aux::gcd_aux< typename N1::value_type, N1::value, N1::value==0,
Chris@16:                         typename N2::value_type, N2::value, N2::value==0  > >
Chris@16:     {
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: #endif // BOOST_MPL_GCD_HPP_INCLUDED