/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkImageToListAdaptor.h,v $
  Language:  C++
  Date:      $Date: 2009-03-04 15:23:50 $
  Version:   $Revision: 1.39 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even 
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#ifndef __itkImageToListAdaptor_h
#define __itkImageToListAdaptor_h

#include <typeinfo>

#include "itkImage.h"
#include "itkPixelTraits.h"
#include "itkListSampleBase.h"
#include "itkSmartPointer.h"
#include "itkImageRegionIterator.h"
#include "itkFixedArray.h"
#include "itkMacro.h"

namespace itk { 
namespace Statistics {

/** \class ImageToListAdaptor
 *  \brief This class provides ListSampleBase interfaces to ITK Image
 *
 * After calling SetImage( const Image * ) method to plug in the image object,
 * users can use Sample interfaces to access Image data.
 * However, the resulting data are a list of measurement vectors. The type of
 * data is measurement vector. For example, if the pixel type of Image object 
 * is STL vector< float > and each pixel has two different types of 
 * measurements, intensity and gradient magnitude, this adaptor has
 * measurement vector of type ITK Point< float, 2>, and one element of the Point
 * is intensity and the other is gradient magnitude.
 *
 * There are two concepts of dimensions for this container. One is for Image 
 * object, and the other is for measurement vector dimension.
 * Only when using ITK Index to access data, the former concept is applicable
 * Otherwise, dimensions means dimensions of measurement vectors. 
 *
 * From the above example, there were two elements in a pixel and each pixel
 * provides [] operator for accessing its elements. However, in many cases,
 * The pixel might be a scalar value such as int or float. In this case,
 * The pixel doesn't support [] operator. To deal with this problem,
 * This class has two companion classes, ScalarAccessor and VectorAccessor.
 * If the pixel type is a scalar type, then you don't have change the third
 * template argument. If you have pixel type is vector one and supports
 * [] operator, then replace third argument with VectorAccessor
 *
 * \sa Sample, ListSampleBase
 */

template < class TImage,
           class TMeasurementVector = 
           ITK_TYPENAME TImage::PixelType >
class ITK_EXPORT ImageToListAdaptor : 
    public ListSampleBase< TMeasurementVector >
{
public:
  /** Standard class typedefs */
  typedef ImageToListAdaptor                   Self;
  typedef ListSampleBase< TMeasurementVector > Superclass;
  typedef SmartPointer< Self >                 Pointer;
  typedef SmartPointer<const Self>             ConstPointer;
  
  /** Run-time type information (and related methods). */
  itkTypeMacro(ImageToListAdaptor, ListSampleBase);
  
  /** Method for creation through the object factory. */
  itkNewMacro(Self);
  
  /** Image typedefs */
  typedef TImage                                         ImageType;
  typedef typename ImageType::Pointer                    ImagePointer;
  typedef typename ImageType::ConstPointer               ImageConstPointer;
  typedef typename ImageType::IndexType                  IndexType;
  typedef typename ImageType::PixelType                  PixelType;
  typedef typename ImageType::PixelContainerConstPointer PixelContainerConstPointer;
  typedef typename ImageType::PixelContainer::ElementIdentifier 
                                                         InstanceIdentifier;
  
  /** Image Iterator typedef support */
  typedef ImageRegionIterator< ImageType > IteratorType; 
  typedef PixelTraits< typename TImage::PixelType > PixelTraitsType;

  /** Superclass typedefs for Measurement vector, measurement, 
   * Instance Identifier, frequency, size, size element value */
  typedef typename PixelTraitsType::ValueType            MeasurementType;
  typedef typename Superclass::FrequencyType             FrequencyType;
  typedef typename Superclass::TotalFrequencyType        TotalFrequencyType;
  typedef typename Superclass::MeasurementVectorSizeType MeasurementVectorSizeType;

  /** the number of components in a measurement vector */
  itkStaticConstMacro(MeasurementVectorSize, unsigned int,
                      PixelTraitsType::Dimension);
  
  virtual void SetMeasurementVectorSize( const MeasurementVectorSizeType s )
    {
    // Measurement vector size for this class is fixed as the pixel's 
    // dimension. This method should throw an exception if the user tries to 
    // set the dimension to a different value. 
    if( s != MeasurementVectorSize )
      {
      itkExceptionMacro( << "Measurement vector size for the image adaptor obtained"
          << " from the pixel dimension is: " << MeasurementVectorSize << " but you "
          << "are setting it to " << s);
      }
    }

 unsigned int GetMeasurementVectorSize() const 
   {
   return MeasurementVectorSize;
   } 
    
  

  typedef TMeasurementVector    MeasurementVectorType;
  typedef MeasurementVectorType ValueType;

  /** Method to set the image */
  void SetImage(const TImage* image);

  /** Method to get the image */
  const TImage* GetImage() const;

  /** returns the number of measurement vectors in this container*/
  unsigned int Size() const;

  inline virtual const MeasurementVectorType & GetMeasurementVector(const InstanceIdentifier &id) const;

  inline FrequencyType GetFrequency(const InstanceIdentifier &id) const;

  TotalFrequencyType GetTotalFrequency() const;
  
 
  class Iterator
  {
  public:
    
    Iterator(){}
    
    Iterator(InstanceIdentifier id, Pointer pContainer)
      :m_Id(id),m_Container(pContainer) {}
    
    FrequencyType GetFrequency() const
      { return 1;}

    const MeasurementVectorType & GetMeasurementVector() const
      { return m_Container->GetMeasurementVector(m_Id);} 

    InstanceIdentifier GetInstanceIdentifier() const
      { return m_Id;}

    Iterator& operator++()
      { ++m_Id; return *this;}
    
    Iterator& operator+(int n)
      { m_Id += n; return *this;}
    
    Iterator& operator-(int n)
      { m_Id -= n; return *this;}

    bool operator!=(const Iterator &it)
      {
      if (m_Id != it.m_Id)
        {return true;}

      if (m_Container != it.m_Container)
        { return true;}

      return false;
      } 
    
    bool operator==(const Iterator &it)
      { return !(*this != it);}
    
    Iterator& operator = (const Iterator &iter)
      { 
      m_Id = iter.m_Id; 
      m_Container = iter.m_Container; 
      return *this;
      }

    Iterator(const Iterator &iter)
      {   
      m_Id = iter.m_Id; 
      m_Container = iter.m_Container; 
      }
    
  private:
    InstanceIdentifier m_Id;  // Current id 
    Pointer m_Container;
  };


  class ConstIterator
    {
    public:
    
    ConstIterator(){}
    
    ConstIterator(InstanceIdentifier id, ConstPointer pContainer)
      :m_Id(id),m_Container(pContainer) {}
    
    FrequencyType GetFrequency() const
      { return 1;}

    const MeasurementVectorType & GetMeasurementVector() const
      { return m_Container->GetMeasurementVector(m_Id);} 

    InstanceIdentifier GetInstanceIdentifier() const
      { return m_Id;}

    ConstIterator& operator++()
      { ++m_Id; return *this;}
    
    ConstIterator& operator+(int n)
      { m_Id += n; return *this;}
    
    ConstIterator& operator-(int n)
      { m_Id -= n; return *this;}

    bool operator!=(const ConstIterator &it)
      {
      if (m_Id != it.m_Id)
        {return true;}

      if (m_Container != it.m_Container)
        { return true;}

      return false;
      }
    
    bool operator==(const ConstIterator &it)
      { return !(*this != it);}
    
    ConstIterator& operator = (const ConstIterator &iter)
      {
      m_Id = iter.m_Id; 
      m_Container = iter.m_Container; 
      return *this;
      }

    ConstIterator(const ConstIterator &iter)
      { 
      m_Id = iter.m_Id; 
      m_Container = iter.m_Container; 
      }
    
  private:
    InstanceIdentifier m_Id;  // Current id 
    ConstPointer m_Container;
  };

  Iterator Begin()
    { 
    Iterator iter(0, this);
    return iter; 
    }
  
  Iterator End()
    {
    Iterator iter(this->Size(), this); 
    return iter; 
    }

  ConstIterator Begin() const
    { 
    ConstIterator iter(0, this);
    return iter; 
    }
  
  ConstIterator End() const
    {
    ConstIterator iter(this->Size(), this); 
    return iter; 
    }
 
protected:
  ImageToListAdaptor();
  virtual ~ImageToListAdaptor() {}
  void PrintSelf(std::ostream& os, Indent indent) const;  

  itkGetConstReferenceMacro(PixelContainer,PixelContainerConstPointer);
  itkGetConstReferenceMacro(UseBuffer,bool);
  itkGetConstReferenceMacro(ImageBeginIndex,IndexType);
  itkGetConstReferenceMacro(ImageEndIndex,IndexType);


private:
  ImageToListAdaptor(const Self&); //purposely not implemented
  void operator=(const Self&); //purposely not implemented

  PixelContainerConstPointer m_PixelContainer;
  bool                       m_UseBuffer;
  IndexType                  m_ImageBeginIndex;
  IndexType                  m_ImageEndIndex;

  ImageConstPointer m_Image;
}; // end of class ImageToListAdaptor

template < class TImage, class TMeasurementVector >
inline const TMeasurementVector &
ImageToListAdaptor< TImage, TMeasurementVector >
::GetMeasurementVector(const InstanceIdentifier &id) const
{
  if ( m_UseBuffer )
    {
    return *( reinterpret_cast< const MeasurementVectorType* >(&(*m_PixelContainer)[id]) );
    }
  else
    {
    return *(reinterpret_cast< const MeasurementVectorType* >
             ( &(m_Image->GetPixel( m_Image->ComputeIndex( id ) ) ) ) );
    }
}

/** returns the number of measurement vectors in this container*/
template < class TImage, class TMeasurementVector >
inline unsigned int
ImageToListAdaptor< TImage, TMeasurementVector >
::Size() const
{
  return m_PixelContainer->Size();
}

template < class TImage, class TMeasurementVector >
inline typename ImageToListAdaptor< TImage, TMeasurementVector >::FrequencyType
ImageToListAdaptor< TImage, TMeasurementVector >
::GetFrequency(const InstanceIdentifier &) const 
{
  return NumericTraits< FrequencyType >::One;
}

} // end of namespace Statistics
} // end of namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkImageToListAdaptor.txx"
#endif

#endif