itkBufferedImageNeighborhoodPixelAccessPolicy.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 itkBufferedImageNeighborhoodPixelAccessPolicy_h
#define itkBufferedImageNeighborhoodPixelAccessPolicy_h
 
#include "itkIndex.h"
#include "itkOffset.h"
#include "itkSize.h"
 
#include <cassert>
 
namespace itk
{
template <typename TImage>
class BufferedImageNeighborhoodPixelAccessPolicy final
{
private:
  using NeighborhoodAccessorFunctorType = typename TImage::NeighborhoodAccessorFunctorType;
  using PixelType = typename TImage::PixelType;
  using InternalPixelType = typename TImage::InternalPixelType;
 
  using ImageDimensionType = typename TImage::ImageDimensionType;
  static constexpr ImageDimensionType ImageDimension = TImage::ImageDimension;
 
  using IndexType = Index<ImageDimension>;
  using OffsetType = Offset<ImageDimension>;
  using ImageSizeType = Size<ImageDimension>;
 
  // Index value to the image buffer, indexing the current pixel.
  const IndexValueType m_PixelIndexValue;
 
  // A reference to the accessor of the image.
  const NeighborhoodAccessorFunctorType & m_NeighborhoodAccessor;
 
 
  // Private helper function. Calculates and returns the index value of the
  // current pixel within the image buffer.
  static IndexValueType
  CalculatePixelIndexValue(const ImageSizeType &
#if !defined(NDEBUG)
                             // Parameter that is only needed for debug assert.
                             imageSize
#endif
                           ,
                           const OffsetType & offsetTable,
                           const IndexType &  pixelIndex) noexcept
  {
    IndexValueType result = 0;
 
    for (ImageDimensionType i = 0; i < ImageDimension; ++i)
    {
      const auto pixelIndexValue = pixelIndex[i];
      assert((pixelIndexValue >= 0) && (static_cast<SizeValueType>(pixelIndexValue) < imageSize[i]));
      result += pixelIndexValue * offsetTable[i];
    }
    return result;
  }
 
public:
  // Deleted member functions:
  BufferedImageNeighborhoodPixelAccessPolicy() = delete;
  BufferedImageNeighborhoodPixelAccessPolicy &
  operator=(const BufferedImageNeighborhoodPixelAccessPolicy &) = delete;
 
  // Explicitly-defaulted functions:
  ~BufferedImageNeighborhoodPixelAccessPolicy() = default;
  BufferedImageNeighborhoodPixelAccessPolicy(const BufferedImageNeighborhoodPixelAccessPolicy &) noexcept = default;

  BufferedImageNeighborhoodPixelAccessPolicy(const ImageSizeType &                   imageSize,
                                             const OffsetType &                      offsetTable,
                                             const NeighborhoodAccessorFunctorType & neighborhoodAccessor,
                                             const IndexType &                       pixelIndex) noexcept
    : m_PixelIndexValue{ CalculatePixelIndexValue(imageSize, offsetTable, pixelIndex) }
    , m_NeighborhoodAccessor(neighborhoodAccessor)
  {}

  PixelType
  GetPixelValue(const InternalPixelType * const imageBufferPointer) const noexcept
  {
    return m_NeighborhoodAccessor.Get(imageBufferPointer + m_PixelIndexValue);
  }

  void
  SetPixelValue(InternalPixelType * const imageBufferPointer, const PixelType & pixelValue) const noexcept
  {
    m_NeighborhoodAccessor.Set(imageBufferPointer + m_PixelIndexValue, pixelValue);
  }
};
 
} // namespace itk
 
#endif