itkSliceIterator.h

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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkSliceIterator.h,v $
  Language:  C++
  Date:      $Date: 2009-03-03 15:09:26 $
  Version:   $Revision: 1.13 $

  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 __itkSliceIterator_h
#define __itkSliceIterator_h

#include "itkMacro.h"
#include "itkExceptionObject.h"
#include <valarray>
namespace itk {

template<class TPixel, class TContainer>
class ITK_EXPORT SliceIterator
{
public:
  SliceIterator(TContainer *n, std::slice s)
    : m_ContainerPointer(n), m_Pos(0), m_Slice(s) {}

  SliceIterator Begin()
    {
    SliceIterator ans = *this;
    ans.m_Pos = 0;
    return ans;
    }
  
  SliceIterator End()
    {
    SliceIterator ans = *this;
    ans.m_Pos = static_cast<unsigned long>(m_Slice.size());
    return ans;
    }

  SliceIterator operator++()
    {
    m_Pos++;
    return *this;
    }

  SliceIterator operator++(int)
    {
    SliceIterator ans  = *this;
    m_Pos++;
    return ans;
    }

  TPixel& operator[](unsigned long n)
    { return this->Loc(m_Pos=n); }

  TPixel& operator*()
    { return Loc(m_Pos); }

  bool operator==(const SliceIterator &orig)
    {
    return orig.m_Pos == this->m_Pos
      &&   orig.m_Slice.stride() == this->m_Slice.stride()
      &&   orig.m_Slice.start() == this->m_Slice.start();
    }
  
  bool operator!=(const SliceIterator &orig)
    {
      return ! operator==(orig);
    }

  bool operator<(const SliceIterator &orig)
    {
    return this->m_Pos < orig.m_Pos
      &&   this->m_Slice.stride() == orig.m_Slice.stride()
      &&   this->m_Slice.start() == orig.m_Slice.start();
    }
  
private:
  TPixel& Loc(unsigned long n) const
    {
    const unsigned long start  = static_cast<unsigned long>( m_Slice.start() );
    const unsigned long stride = static_cast<unsigned long>( m_Slice.stride() );
    return (*m_ContainerPointer)[ start + n * stride ];
    }  

  TContainer *m_ContainerPointer;

  unsigned long m_Pos;

  std::slice m_Slice;
};
  
} // end namespace itk

#endif