/*=========================================================================
 *
 *  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 itkBinaryOperationConcept_h
#define itkBinaryOperationConcept_h

#include "itkPromoteType.h"

/// \cond HIDE_META_PROGRAMMING
namespace itk
{
namespace Details
{
namespace op
{
/** Root Binary Operation Concept.
 * All binary operations are expected to inherit from this type.
 * These types will help to implement binary operations between arrays (\c
 * VariableLengthVector) through Expression Template technique.
 *
 * \c BinaryOperationConcept subclasses are expected to provide a template
 * function \c apply() that implements the actual binary operation (addition,
 * subtraction, ...).
 * \ingroup ITKCommon
 * \sa \c itk::VariableLengthVector
 * \sa \c itk::VariableLengthVectorExpression
 */
struct BinaryOperationConcept
{};

/** Addition operation.
 * The result type will be automatically promoted to the best type.
 * \ingroup ITKCommon
 */
struct Plus : BinaryOperationConcept
{
  template <typename T1, typename T2>
  static typename mpl::PromoteType<T1, T2>::Type
  Apply(T1 const & lhs, T2 const & rhs)
  {
    return lhs + rhs;
  }
};

/** Subtraction operation.
 * The result type will be automatically promoted to the best type.
 * \ingroup ITKCommon
 */
struct Sub : BinaryOperationConcept
{
  template <typename T1, typename T2>
  static typename mpl::PromoteType<T1, T2>::Type
  Apply(T1 const & lhs, T2 const & rhs)
  {
    return lhs - rhs;
  }
};

/** Multiplication operation.
 * The result type will be automatically promoted to the best type.
 * \ingroup ITKCommon
 */
struct Mult : BinaryOperationConcept
{
  template <typename T1, typename T2>
  static typename mpl::PromoteType<T1, T2>::Type
  Apply(T1 const & lhs, T2 const & rhs)
  {
    return lhs * rhs;
  }
};

/** Division operation.
 * The result type will be automatically promoted to the best type.
 * \ingroup ITKCommon
 */
struct Div : BinaryOperationConcept
{
  template <typename T1, typename T2>
  static typename mpl::PromoteType<T1, T2>::Type
  Apply(T1 const & lhs, T2 const & rhs)
  {
    return lhs / rhs;
  }
};

} // namespace op
} // namespace Details
} // namespace itk
/// \endcond

#endif // itkBinaryOperationConcept_h
