itkImageConstIteratorWithOnlyIndex.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 itkImageConstIteratorWithOnlyIndex_h
#define itkImageConstIteratorWithOnlyIndex_h
 
#include "itkIndex.h"
#include "itkImage.h"
#include <memory>
#include <type_traits> // For remove_const_t.
 
namespace itk
{
template <typename TImage>
class ITK_TEMPLATE_EXPORT ImageConstIteratorWithOnlyIndex
{
public:
  ITK_DEFAULT_COPY_AND_MOVE(ImageConstIteratorWithOnlyIndex);

  using Self = ImageConstIteratorWithOnlyIndex;

  static constexpr unsigned int ImageDimension = TImage::ImageDimension;

  using IndexType = typename TImage::IndexType;
  using IndexValueType = typename IndexType::IndexValueType;

  using SizeType = typename TImage::SizeType;
  using SizeValueType = typename SizeType::SizeValueType;

  using RegionType = typename TImage::RegionType;

  using ImageType = TImage;

  using OffsetType = typename TImage::OffsetType;
  using OffsetValueType = typename OffsetType::OffsetValueType;

  ImageConstIteratorWithOnlyIndex() = default;

  ImageConstIteratorWithOnlyIndex(const TImage * ptr, const RegionType & region);

  virtual ~ImageConstIteratorWithOnlyIndex() = default;

  static constexpr unsigned int
  GetImageDimension()
  {
    return ImageDimension;
  }

  bool
  operator==(const Self & it) const
  {
    // two iterators are the same if they "point to" the same memory location
    return (m_PositionIndex) == (it.m_PositionIndex);
  }
 
  ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(Self);

  bool
  operator<=(const Self & it) const
  {
    // an iterator is "less than" another if it "points to" a lower
    // memory location
    return (m_PositionIndex) <= (it.m_PositionIndex);
  }

  bool
  operator<(const Self & it) const
  {
    // an iterator is "less than" another if it "points to" a lower
    // memory location
    return (m_PositionIndex) < (it.m_PositionIndex);
  }

  bool
  operator>=(const Self & it) const
  {
    // an iterator is "greater than" another if it "points to" a higher
    // memory location
    return (m_PositionIndex) >= (it.m_PositionIndex);
  }

  bool
  operator>(const Self & it) const
  {
    // an iterator is "greater than" another if it "points to" a higher
    // memory location
    return (m_PositionIndex) > (it.m_PositionIndex);
  }

  [[nodiscard]] const IndexType &
  GetIndex() const
  {
    return m_PositionIndex;
  }

  [[nodiscard]] const RegionType &
  GetRegion() const
  {
    return m_Region;
  }

  void
  SetIndex(const IndexType & ind)
  {
    m_PositionIndex = ind;
  }

  void
  GoToBegin();

  void
  GoToReverseBegin();

  [[nodiscard]] bool
  IsAtReverseEnd() const
  {
    return !m_Remaining;
  }

  [[nodiscard]] bool
  IsAtEnd() const
  {
    return !m_Remaining;
  }

  bool
  Remaining()
  {
    return m_Remaining;
  }
 
protected:                            // made protected so other iterators can access
  IndexType m_PositionIndex{ { 0 } }; // Index where we currently are
  IndexType m_BeginIndex{ { 0 } };    // Index to start iterating over
  IndexType m_EndIndex{ { 0 } };      // Index to finish iterating:
                                      // one pixel past the end of each
                                      // row, col, slice, etc....
 
  RegionType m_Region{}; // region to iterate over
 
  bool m_Remaining{ false };
};
 
// Deduction guide for class template argument deduction (CTAD).
template <typename TImage>
ImageConstIteratorWithOnlyIndex(SmartPointer<TImage>, const typename TImage::RegionType &)
  -> ImageConstIteratorWithOnlyIndex<std::remove_const_t<TImage>>;
 
} // end namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkImageConstIteratorWithOnlyIndex.hxx"
#endif
 
#endif