itkSubsample.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 itkSubsample_h
#define itkSubsample_h
 
#include "itkSample.h"
#include "itkMacro.h"
#include "itkObjectFactory.h"
 
namespace itk
{
namespace Statistics
{
template <typename TSample>
class ITK_TEMPLATE_EXPORT Subsample : public TSample
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(Subsample);

  using Self = Subsample;
  using Superclass = TSample;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  itkOverrideGetNameOfClassMacro(Subsample);

  itkNewMacro(Self);

  using SamplePointer = typename TSample::Pointer;

  using MeasurementVectorType = typename TSample::MeasurementVectorType;
  using MeasurementType = typename TSample::MeasurementType;
  using InstanceIdentifier = typename TSample::InstanceIdentifier;
  using ValueType = MeasurementVectorType;
 
  using AbsoluteFrequencyType = typename TSample::AbsoluteFrequencyType;
  using TotalAbsoluteFrequencyType = typename TSample::TotalAbsoluteFrequencyType;

  using InstanceIdentifierHolder = std::vector<InstanceIdentifier>;

  const InstanceIdentifierHolder &
  GetIdHolder() const
  {
    return this->m_IdHolder;
  }

  void
  SetSample(const TSample * sample);
 
  const TSample *
  GetSample() const;

  void
  InitializeWithAllInstances();

  void
  AddInstance(InstanceIdentifier id);

  InstanceIdentifier
  Size() const override;

  void
  Clear();

  const MeasurementVectorType &
  GetMeasurementVector(InstanceIdentifier id) const override;

  AbsoluteFrequencyType
  GetFrequency(InstanceIdentifier id) const override;

  TotalAbsoluteFrequencyType
  GetTotalFrequency() const override;
 
  void
  Swap(unsigned int index1, unsigned int index2);
 
  InstanceIdentifier
  GetInstanceIdentifier(unsigned int index);
 
  const MeasurementVectorType &
  GetMeasurementVectorByIndex(unsigned int index) const;
 
  AbsoluteFrequencyType
  GetFrequencyByIndex(unsigned int index) const;

  void
  Graft(const DataObject * thatObject) override;
 
  class ConstIterator
  {
    friend class Subsample;
 
  public:
    ConstIterator(const Self * sample) { *this = sample->Begin(); }
 
    ConstIterator(const ConstIterator & iter)
    {
      m_Iter = iter.m_Iter;
      m_Subsample = iter.m_Subsample;
      m_Sample = iter.m_Sample;
    }
 
    ConstIterator &
    operator=(const ConstIterator & iter)
    {
      m_Iter = iter.m_Iter;
      m_Subsample = iter.m_Subsample;
      m_Sample = iter.m_Sample;
      return *this;
    }
 
    bool
    operator==(const ConstIterator & it) const
    {
      return (m_Iter == it.m_Iter);
    }
 
    ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(ConstIterator);
 
    ConstIterator &
    operator++()
    {
      ++m_Iter;
      return *this;
    }
 
    AbsoluteFrequencyType
    GetFrequency() const
    {
      return m_Sample->GetFrequency(*m_Iter);
    }
 
    const MeasurementVectorType &
    GetMeasurementVector() const
    {
      return m_Sample->GetMeasurementVector(*m_Iter);
    }
 
    InstanceIdentifier
    GetInstanceIdentifier() const
    {
      return (m_Iter - m_Subsample->GetIdHolder().begin());
    }
 
  protected:
    // Purposely not implemented
    ConstIterator();
 
    // Only to be called from the Subsample
    ConstIterator(typename InstanceIdentifierHolder::const_iterator iter, const Self * classSample)
      : m_Iter(iter)
      , m_Subsample(classSample)
      , m_Sample(classSample->GetSample())
    {}
 
    // ConstIterator pointing to ImageToListSampleAdaptor
    typename InstanceIdentifierHolder::const_iterator m_Iter;
 
    // Pointer to Subsample object
    const Self *    m_Subsample;
    const TSample * m_Sample;
 
  private:
  };
 
  class Iterator : public ConstIterator
  {
    friend class Subsample;
 
  public:
    Iterator(Self * sample)
      : ConstIterator(sample)
    {}
 
    Iterator(const Iterator & iter)
      : ConstIterator(iter)
    {}
 
    Iterator &
    operator=(const Iterator & iter)
    {
      this->ConstIterator::operator=(iter);
      return *this;
    }
 
  protected:
    // To ensure const-correctness these method must not be in the public API.
    // The are purposely not implemented, since they should never be called.
    Iterator();
    Iterator(const Self * sample);
    Iterator(typename InstanceIdentifierHolder::const_iterator iter, const Self * classSample);
    Iterator(const ConstIterator & it);
    ConstIterator &
    operator=(const ConstIterator & it);
 
    // Only to be called from the Subsample
    Iterator(typename InstanceIdentifierHolder::iterator iter, Self * classSample)
      : ConstIterator(iter, classSample)
    {}
 
  private:
  };

  Iterator
  Begin()
  {
    const Iterator iter(m_IdHolder.begin(), this);
 
    return iter;
  }

  Iterator
  End()
  {
    const Iterator iter(m_IdHolder.end(), this);
 
    return iter;
  }
 
  ConstIterator
  Begin() const
  {
    const ConstIterator iter(m_IdHolder.begin(), this);
 
    return iter;
  }
 
  ConstIterator
  End() const
  {
    const ConstIterator iter(m_IdHolder.end(), this);
 
    return iter;
  }
 
protected:
  Subsample();
  ~Subsample() override = default;
  void
  PrintSelf(std::ostream & os, Indent indent) const override;
 
private:
  const TSample *            m_Sample{};
  InstanceIdentifierHolder   m_IdHolder{};
  unsigned int               m_ActiveDimension{};
  TotalAbsoluteFrequencyType m_TotalFrequency{};
}; // end of class
} // end of namespace Statistics
} // end of namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkSubsample.hxx"
#endif
 
#endif