itkVectorImageNeighborhoodAccessorFunctor.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 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)
  {}
  VectorImageNeighborhoodAccessorFunctor() = default;

  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{ nullptr };   // Begin of the buffer.
};
} // end namespace itk
#endif