itkIsConvertible.h

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/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef itkIsConvertible_h
#define itkIsConvertible_h
 
#include "itkMacro.h"
 
#if !defined(ITK_LEGACY_REMOVE)
 
#  include "itkMetaProgrammingLibrary.h"
 
namespace itk
{
 
namespace mpl
{
namespace Details
{
 
struct SfinaeTypes
{
  using TOne = char;
  struct TTwo
  {
    char arr__[2];
  };
};
} // namespace Details
 
template <typename TFrom, typename TTo>
struct IsConvertible : private Details::SfinaeTypes
{
private:
  static TOne Test(TTo);
  static TTwo
  Test(...);
  static TFrom
  MakeT();
public:
  static constexpr bool Value = sizeof(Test(MakeT())) == sizeof(TOne);
};
 
} // end namespace mpl
 
// itk::IsConvertible has moved to itk::mpl.
// Expect itk::IsConvertible to be deprecated.
using mpl::IsConvertible;
 
} // end namespace itk
 
#else // ITK_LEGACY_REMOVE
#  error Use C++ 11 std::is_convertible directly
#endif
 
#endif // itkIsConvertible_h