itkIsConvertible.h

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/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  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
 *
 *         http://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 "itkMetaProgrammingLibrary.h"

namespace itk
{

namespace mpl
{
namespace Details
{

struct SfinaeTypes
  {
  typedef char                       TOne;
  typedef struct  { char arr__[2]; } TTwo;
  };
} // Details namespace

template <typename TFrom, typename TTo>
struct IsConvertible
: private Details::SfinaeTypes
{
private:
  static TOne Test(TTo);
  static TTwo Test(...);
  static TFrom MakeT();
public:
  static ITK_CONSTEXPR_VAR bool Value = sizeof(Test(MakeT())) == sizeof(TOne);
};

} // itk::mpl namespace

// itk::IsConvertible has moved to itk::mpl.
// Expect itk::IsConvertible to be deprecated.
using mpl::IsConvertible;

} // itk namespace
#endif // itkIsConvertible_h