itkConstShapedNeighborhoodIterator.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 itkConstShapedNeighborhoodIterator_h
#define itkConstShapedNeighborhoodIterator_h
 
#include <vector>
#include <list>
#include <type_traits> // For remove_const_t.
 
#include "itkNeighborhoodIterator.h"
 
namespace itk
{
template <typename TImage, typename TBoundaryCondition = ZeroFluxNeumannBoundaryCondition<TImage>>
class ITK_TEMPLATE_EXPORT ConstShapedNeighborhoodIterator : private NeighborhoodIterator<TImage, TBoundaryCondition>
{
public:
  using InternalPixelType = typename TImage::InternalPixelType;
  using PixelType = typename TImage::PixelType;

  static constexpr unsigned int Dimension = TImage::ImageDimension;

  using Self = ConstShapedNeighborhoodIterator;
  using Superclass = NeighborhoodIterator<TImage, TBoundaryCondition>;

  using typename Superclass::OffsetType;
  using OffsetValueType = typename OffsetType::OffsetValueType;
  using typename Superclass::RadiusType;
  using typename Superclass::SizeType;
  using SizeValueType = typename SizeType::SizeValueType;

  using ImageType = TImage;
  using RegionType = typename TImage::RegionType;
  using IndexType = Index<Self::Dimension>;
  using IndexValueType = typename IndexType::IndexValueType;
  using NeighborhoodType = Neighborhood<PixelType, Self::Dimension>;
 
  using NeighborIndexType = typename NeighborhoodType::NeighborIndexType;

  using IndexListType = std::list<NeighborIndexType>;
 
  using IndexListIterator = typename IndexListType::iterator;
  using IndexListConstIterator = typename IndexListType::const_iterator;

  using BoundaryConditionType = TBoundaryCondition;

  using ImageBoundaryConditionPointerType = ImageBoundaryCondition<ImageType> *;

  struct ConstIterator
  {
    ConstIterator()
      : m_NeighborhoodIterator(nullptr)
    {}
    ConstIterator(Self * s)
      : m_NeighborhoodIterator(s)
    {
      this->GoToBegin();
    }
 
    ~ConstIterator() = default;
 
    ConstIterator &
    operator=(const ConstIterator & o) = default;
 
    ConstIterator(const ConstIterator & o)
      : m_NeighborhoodIterator(o.m_NeighborhoodIterator)
      , m_ListIterator(o.m_ListIterator)
    {}
 
    void
    operator++(int)
    {
      ++m_ListIterator;
    }
 
    void
    operator--(int)
    {
      --m_ListIterator;
    }
 
    const ConstIterator &
    operator++()
    {
      ++m_ListIterator;
      return *this;
    }
 
    const ConstIterator &
    operator--()
    {
      --m_ListIterator;
      return *this;
    }
 
    bool
    operator==(const ConstIterator & o) const
    {
      return m_ListIterator == o.m_ListIterator;
    }
 
    ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(ConstIterator);
 
    [[nodiscard]] bool
    IsAtEnd() const
    {
      if (m_ListIterator == m_NeighborhoodIterator->GetActiveIndexList().end())
      {
        return true;
      }
 
      return false;
    }
 
    void
    GoToBegin()
    {
      m_ListIterator = m_NeighborhoodIterator->GetActiveIndexList().begin();
    }
 
    void
    GoToEnd()
    {
      m_ListIterator = m_NeighborhoodIterator->GetActiveIndexList().end();
    }
 
    [[nodiscard]] PixelType
    Get() const
    {
      return m_NeighborhoodIterator->GetPixel(*m_ListIterator);
    }
 
    [[nodiscard]] OffsetType
    GetNeighborhoodOffset() const
    {
      return m_NeighborhoodIterator->GetOffset(*m_ListIterator);
    }
 
    [[nodiscard]] typename IndexListType::value_type
    GetNeighborhoodIndex() const
    {
      return *m_ListIterator;
    }
 
  protected:
    friend Self;
 
    ConstIterator(const Self * s, const typename IndexListType::const_iterator & li)
      : m_NeighborhoodIterator(const_cast<Self *>(s))
      , m_ListIterator(li)
    {}
 
    Self * m_NeighborhoodIterator;
 
    typename IndexListType::const_iterator m_ListIterator;
 
    void
    ProtectedSet(const PixelType & v) const
    {
      m_NeighborhoodIterator->SetPixel(*m_ListIterator, v);
    }
  };

  ConstIterator
  Begin() const
  {
    return ConstIterator(this, this->m_ActiveIndexList.begin());
  }

  ConstIterator
  End() const
  {
    return ConstIterator(this, this->m_ActiveIndexList.end());
  }

  ConstShapedNeighborhoodIterator() = default;

  ~ConstShapedNeighborhoodIterator() override = default;

  ConstShapedNeighborhoodIterator(const SizeType & radius, const TImage * ptr, const RegionType & region)
    : Superclass(radius, const_cast<ImageType *>(ptr), region)
  {}

  ConstShapedNeighborhoodIterator(const ConstShapedNeighborhoodIterator &) = delete;
 
  // Expose the following methods from the superclass.  This is a
  // restricted subset of the methods available for
  // ConstNeighborhoodIterator.
  using Superclass::GetImagePointer;
  using Superclass::GetRadius;
  using Superclass::GetIndex;
  using Superclass::GetNeighborhoodIndex;
  using Superclass::GetCenterNeighborhoodIndex;
  using Superclass::GetRegion;
  using Superclass::GetBeginIndex;
  using Superclass::GoToBegin;
  using Superclass::GoToEnd;
  using Superclass::IsAtBegin;
  using Superclass::IsAtEnd;
  using Superclass::GetOffset;
  using Superclass::operator==;
#ifndef ITK_EXPERIMENTAL_CXX20_REWRITTEN_UNEQUAL_OPERATOR
  using Superclass::operator!=;
#endif
  using Superclass::operator<;
  using Superclass::operator>;
  using Superclass::operator>=;
  using Superclass::operator<=;
  using Superclass::operator[];
  using Superclass::GetElement;
  using Superclass::SetLocation;
  using Superclass::GetCenterPointer;
  using Superclass::GetCenterPixel;
  using Superclass::OverrideBoundaryCondition;
  using Superclass::ResetBoundaryCondition;
  using Superclass::GetBoundaryCondition;
  using Superclass::SetBoundaryCondition;
  using Superclass::GetNeedToUseBoundaryCondition;
  using Superclass::SetNeedToUseBoundaryCondition;
  using Superclass::NeedToUseBoundaryConditionOn;
  using Superclass::NeedToUseBoundaryConditionOff;
  using Superclass::Print;
  using Superclass::operator-;
  using Superclass::GetPixel;
  using Superclass::SetRegion;

  Self &
  operator=(const Self & orig)
  {
    if (this != &orig)
    {
      Superclass::operator=(orig);
      m_ActiveIndexList = orig.m_ActiveIndexList;
      m_CenterIsActive = orig.m_CenterIsActive;
    }
    return *this;
  }

  void
  PrintSelf(std::ostream &, Indent) const override;

  void
  ActivateOffset(const OffsetType & off)
  {
    this->ActivateIndex(Superclass::GetNeighborhoodIndex(off));
  }
  void
  DeactivateOffset(const OffsetType & off)
  {
    this->DeactivateIndex(Superclass::GetNeighborhoodIndex(off));
  }

  template <typename TOffsets>
  void
  ActivateOffsets(const TOffsets & offsets)
  {
    for (const auto & offset : offsets)
    {
      this->ActivateOffset(offset);
    }
  }

  void
  ClearActiveList()
  {
    m_ActiveIndexList.clear();
    m_CenterIsActive = false;
  }

  const IndexListType &
  GetActiveIndexList() const
  {
    return m_ActiveIndexList;
  }

  typename IndexListType::size_type
  GetActiveIndexListSize() const
  {
    return m_ActiveIndexList.size();
  }

  template <typename TNeighborPixel>
  void
  CreateActiveListFromNeighborhood(const Neighborhood<TNeighborPixel, Self::Dimension> &);
  void
  CreateActiveListFromNeighborhood(const NeighborhoodType & neighborhood)
  {
    // just delegate to the templated version
    this->CreateActiveListFromNeighborhood<PixelType>(neighborhood);
  }

  Self &
  operator++();

  Self &
  operator--();

  Self &
  operator+=(const OffsetType &);

  Self &
  operator-=(const OffsetType &);
 
protected:
  using Superclass::SetPixel;
  using Superclass::SetCenterPixel;
 
  friend struct ConstIterator;

  //  Superclass::SetPixel;
  //  Superclass::SetCenterPixel;

  void ActivateIndex(NeighborIndexType);
 
  void DeactivateIndex(NeighborIndexType);
 
 
  bool          m_CenterIsActive{ false };
  IndexListType m_ActiveIndexList{};
};
 
// Deduction guide for class template argument deduction (CTAD).
template <typename TImage>
ConstShapedNeighborhoodIterator(const typename TImage::SizeType &,
                                SmartPointer<TImage>,
                                const typename TImage::RegionType &)
  -> ConstShapedNeighborhoodIterator<std::remove_const_t<TImage>>;
 
} // namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkConstShapedNeighborhoodIterator.hxx"
#endif
 
#endif