itkVectorImageNeighborhoodAccessorFunctor.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 itkVectorImageNeighborhoodAccessorFunctor_h
#define itkVectorImageNeighborhoodAccessorFunctor_h

#include "itkVariableLengthVector.h"
#include "itkImageBoundaryCondition.h"
#include "itkImageBase.h"

namespace itk
{
template< typename TImage >
class VectorImageNeighborhoodAccessorFunctor
{
public:
  using ImageType = TImage;
  using PixelType = typename ImageType::PixelType;
  using InternalPixelType = typename ImageType::InternalPixelType;
  using VectorLengthType = unsigned int;
  using OffsetType = typename ImageType::OffsetType;

  using NeighborhoodType = Neighborhood< InternalPixelType *,
                         TImage ::ImageDimension >;

  template<typename TOutput=ImageType>
  using ImageBoundaryConditionType = ImageBoundaryCondition<ImageType, TOutput>;

  VectorImageNeighborhoodAccessorFunctor(VectorLengthType length):
    m_VectorLength(length), m_OffsetMultiplier(length - 1), m_Begin(nullptr) {}
  VectorImageNeighborhoodAccessorFunctor():
     m_Begin(nullptr) {}

  inline void SetBegin(const InternalPixelType *begin)
  { this->m_Begin = const_cast< InternalPixelType * >( begin ); }

  inline PixelType Get(const InternalPixelType *pixelPointer) const
  {
    return PixelType(pixelPointer + ( pixelPointer - m_Begin ) * m_OffsetMultiplier, m_VectorLength);
  }

  inline void Set(InternalPixelType * const pixelPointer, const PixelType & p) const
  {
    InternalPixelType * const truePixelPointer =
      pixelPointer + ( pixelPointer - m_Begin ) * m_OffsetMultiplier;

    for ( VectorLengthType i = 0; i < m_VectorLength; i++ )
      {
      truePixelPointer[i] = p[i];
      }
  }


  template <typename TOutput>
  inline typename ImageBoundaryConditionType<TOutput>::OutputPixelType
  BoundaryCondition(
    const OffsetType & point_index,
    const OffsetType & boundary_offset,
    const NeighborhoodType *data,
    const ImageBoundaryConditionType<TOutput> * boundaryCondition) const
  {
    return boundaryCondition->operator()(point_index, boundary_offset, data, *this);
  }

  void SetVectorLength(VectorLengthType length)
  {
    m_VectorLength = length;
    m_OffsetMultiplier = length - 1;
  }

  VectorLengthType GetVectorLength()
  {
    return m_VectorLength;
  }

private:
  VectorLengthType m_VectorLength{0};
  VectorLengthType m_OffsetMultiplier{0}; // m_OffsetMultiplier = m_VectorLength-1
                                       // (precomputed for speedup).
  InternalPixelType *m_Begin;          // Begin of the buffer.
};
} // end namespace itk
#endif