dust3d/thirdparty/cgal/CGAL-5.1/include/CGAL/Rational_traits.h

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// Copyright (c) 2006-2007 Max-Planck-Institute Saarbruecken (Germany).
// All rights reserved.
//
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// This file is part of CGAL (www.cgal.org)
//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/Algebraic_foundations/include/CGAL/Rational_traits.h $
// $Id: Rational_traits.h 0779373 2020-03-26T13:31:46+01:00 Sébastien Loriot
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s) : Michael Hemmer <hemmer@mpi-inf.mpg.de>
//
// =============================================================================
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// This file is for backward compatibility
// Rational_traits will be replaced by Fraction_traits
#ifndef CGAL_RATIONAL_TRAITS_H
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#define CGAL_RATIONAL_TRAITS_H
#include <CGAL/number_type_basic.h>
#include <CGAL/Fraction_traits.h>
#include <CGAL/is_convertible.h>
#include <boost/utility/enable_if.hpp>
namespace CGAL {
namespace internal{
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template <class Rational, bool >
struct Rational_traits_base
{
typedef Rational RT;
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const RT& numerator (const Rational& r) const { return r; }
RT denominator (const Rational&) const { return RT(1); }
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template<class T>
Rational make_rational(const T & x) const
{ return x; }
template<class T, class U>
Rational make_rational(const std::pair<T, U> & x) const
{ return make_rational(x.first, x.second); }
Rational make_rational(const RT & n, const RT & d) const
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{ return n / d; }
};
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template <class Rational>
struct Rational_traits_base<Rational, true>
{
private:
typedef Fraction_traits<Rational> FT;
typedef typename FT::Decompose Decomose;
typedef typename FT::Compose Compose;
public:
typedef typename FT::Numerator_type RT;
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RT numerator (const Rational& r) const {
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RT num,den;
Decomose()(r,num,den);
return num;
}
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RT denominator (const Rational& r) const {
RT num,den;
Decomose()(r,num,den);
return den;
}
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template<class T>
Rational make_rational(const T & x) const
{ return x; }
template<class T, class U>
Rational make_rational(const std::pair<T, U> & x) const
{ return make_rational(x.first, x.second); }
template<class N,class D>
Rational make_rational(const N& n, const D& d,typename boost::enable_if_c<is_implicit_convertible<N,RT>::value&&is_implicit_convertible<D,RT>::value,int>::type=0) const
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{ return Compose()(n,d); }
template<class N,class D>
Rational make_rational(const N& n, const D& d,typename boost::enable_if_c<!is_implicit_convertible<N,RT>::value||!is_implicit_convertible<D,RT>::value,int>::type=0) const
{ return n/d; } // Assume that n or d is already a fraction
};
}// namespace internal
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// use Fraction_traits if Is_fraction && Num and Den are the same
template <class T>
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class Rational_traits
: public internal::Rational_traits_base<T,
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::boost::is_same<typename Fraction_traits<T>::Is_fraction,Tag_true>::value
&&
::boost::is_same<
typename Fraction_traits<T>::Numerator_type,
typename Fraction_traits<T>::Denominator_type
>::value >
{};
} //namespace CGAL
#endif // CGAL_RATIONAL_TRAITS_H
// EOF