// Created on: 2014-01-10
// Created by: Denis BOGOLEPOV
// Copyright (c) 2013-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

// =======================================================================
// function : Perform
// purpose  :
// =======================================================================
template<class T, int N>
void BVH_Sorter<T, N>::Perform (BVH_Set<T, N>*         theSet,
                                const Standard_Integer theAxis)
{
  Perform (theSet, theAxis, 0, theSet->Size() - 1);
}

// =======================================================================
// function : Perform
// purpose  :
// =======================================================================
template<class T, int N>
void BVH_Sorter<T, N>::Perform (BVH_Set<T, N>*         theSet,
                                const Standard_Integer theAxis,
                                const Standard_Integer theBegElement,
                                const Standard_Integer theEndElement)
{
  Standard_Integer aLft = theBegElement;
  Standard_Integer aRgh = theEndElement;

  T aPivot = theSet->Center ((aRgh + aLft) / 2, theAxis);

  while (aLft < aRgh)
  {
    while (theSet->Center (aLft, theAxis) < aPivot && aLft < theEndElement)
    {
      ++aLft;
    }

    while (theSet->Center (aRgh, theAxis) > aPivot && aRgh > theBegElement)
    {
      --aRgh;
    }

    if (aLft <= aRgh)
    {
      if (aLft != aRgh)
      {
        theSet->Swap (aLft, aRgh);
      }

      ++aLft;
      --aRgh;
    }
  }

  if (aRgh > theBegElement)
  {
    Perform (theSet, theAxis, theBegElement, aRgh);
  }

  if (aLft < theEndElement)
  {
    Perform (theSet, theAxis, aLft, theEndElement);
  }
}