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

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C++

// Copyright (c) 2017 GeometryFactory (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org)
//
// $URL: https://github.com/CGAL/cgal/blob/v5.1/Kernel_23/include/CGAL/Has_conversion.h $
// $Id: Has_conversion.h 52164b1 2019-10-19T15:34:59+02:00 Sébastien Loriot
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
// Author(s) : Mael Rouxel-Labbé
#ifndef CGAL_HAS_CONVERSION_H
#define CGAL_HAS_CONVERSION_H
#include <CGAL/Cartesian_converter.h>
#include <CGAL/Homogeneous_converter.h>
#include <CGAL/representation_tags.h>
namespace CGAL {
namespace internal {
template<typename K1, typename K2, typename Rep = typename K1::Rep_tag /* Cartesian_tag */>
struct Converter_selector
{
CGAL_static_assertion_msg((boost::is_same<typename K1::Rep_tag,
typename K2::Rep_tag>::value),
"Kernels must have the same representation");
typedef CGAL::Cartesian_converter<K1, K2> type;
};
template<typename K1, typename K2>
struct Converter_selector<K1, K2, Homogeneous_tag>
{
CGAL_static_assertion_msg((boost::is_same<typename K1::Rep_tag,
typename K2::Rep_tag>::value),
"Kernels must have the same representation");
typedef CGAL::Homogeneous_converter<K1, K2> type;
};
} // namespace internal
/// Check whether Cartesian/Homogeneous_converter<K1, K2> provides either
/// of the following conversions:
///
/// -- K2T operator()(const K1T& ) const
/// -- const K2T& operator()(const K1T& ) const
///
/// \pre K1 and K2 are kernels with the same representation tag
/// \pre K1T is a typedef in K1
/// \pre K2T is a typedef in K2
template<typename K1, typename K2, typename K1T, typename K2T>
class Has_conversion
{
typedef char one;
typedef struct { char arr[2]; } two;
template<typename U, U>
struct Wrapper { };
template<typename CC, typename T1, typename T2>
static one test(Wrapper<T2 (CC::*)(const T1&) const, &CC::operator()>*);
template<typename CC, typename T1, typename T2>
static one test(Wrapper<const T2& (CC::*)(const T1&) const, &CC::operator()>*);
template<typename CC, typename T1, typename T2>
static two test(...);
public:
static const bool value =
sizeof(test<typename internal::Converter_selector<K1, K2>::type, K1T, K2T >(0)) == 1;
};
} // namespace CGAL
#endif // CGAL_HAS_CONVERSION_H