canonical.h

 
//          Copyright John McFarlane 2018.
// Distributed under the Boost Software License, Version 1.0.
//    (See accompanying file ../LICENSE_1_0.txt or copy at
//          http://www.boost.org/LICENSE_1_0.txt)
 
#if !defined(CNL_IMPL_FRACTION_CANONICAL_H)
#define CNL_IMPL_FRACTION_CANONICAL_H
 
#include "definition.h"
#include "reduce.h"
 
namespace cnl {
    namespace _impl {
        template<typename Numerator, typename Denominator>
        [[nodiscard]] constexpr auto negated(fraction<Numerator, Denominator> const& rhs)
        {
            return _impl::make_fraction(-rhs.numerator, -rhs.denominator);
        }
 
        template<typename Numerator, typename Denominator>
        [[nodiscard]] constexpr auto canonical_from_reduce(
                fraction<Numerator, Denominator> const& f)
        {
            return (f.denominator < Denominator(0.)) ? negated(f) : f;
        }
 
        template<typename Numerator, typename Denominator>
        [[nodiscard]] constexpr auto canonical(fraction<Numerator, Denominator> const& f)
        {
            return canonical_from_reduce(reduce(f));
        }
    }
}
 
#endif  // CNL_IMPL_FRACTION_CANONICAL_H