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

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkAMRBox.h,v $

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/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 notice for more information.

=========================================================================*/
// .NAME vtkAMRBox - represents a 3D uniform region in space
// .SECTION Description
// vtkAMRBox is similar to Chombo's Box. It represents a 3D
// region by storing indices for two corners (LoCorner, HiCorner).
// A few utility methods are provided.

#ifndef __vtkAMRBox_h
#define __vtkAMRBox_h

#include "vtkObject.h"

#include <assert.h>

template<int dimension>
struct vtkAMRBoxInitializeHelp;

// Helper to unroll the loop
template<int dimension>
void vtkAMRBoxInitialize(int *LoCorner, int *HiCorner, // member
                         const int *loCorner, const int *hiCorner, // local
                         vtkAMRBoxInitializeHelp<dimension>* = 0) // dummy parameter for vs6
  {
  for(int i=0; i<dimension; ++i)
    {
    LoCorner[i] = loCorner[i];
    HiCorner[i] = hiCorner[i];
    }
  for(int i=dimension; i<(3-dimension); ++i)
    {
    LoCorner[i] = 0;
    HiCorner[i] = 0;
    }
  }

class VTK_FILTERING_EXPORT vtkAMRBox
{
public:
  // Public for quick access.
  
  // Description:
  // Cell position of the lower cell and higher cell defining the box.
  // Both cells are defined at the same level of refinement. The refinement
  // level itself is not specified.
  // Invariant: LoCorner<=HiCorner
  // Eg. LoCorner = {0,0,0}, HiCorner = {0,0,0} is an AMRBox with 1 cell
  int LoCorner[3];
  int HiCorner[3];

  // Description:
  // Default constructor: lower corner box made of one cell.
  vtkAMRBox()
    {
      vtkAMRBoxInitialize<0>(this->LoCorner, this->HiCorner, 0, 0);
    }
  
  // Description:
  // Constructor.
  // \pre dimensionality >= 2 && dimensionality <= 3
  vtkAMRBox(int dimensionality, const int* loCorner, const int* hiCorner)
    {
      switch(dimensionality)
        {
        case 2:
          vtkAMRBoxInitialize<2>(this->LoCorner, this->HiCorner,
                                 loCorner, hiCorner);
          break;
        case 3:
          vtkAMRBoxInitialize<3>(this->LoCorner, this->HiCorner,
                                 loCorner, hiCorner);
          break;
        default:
          vtkGenericWarningMacro( "Wrong dimensionality" );
        }
    }
  
  // Description:
  // Returns the number of cells (aka elements, zones etc.) in
  // the given region (for the specified refinement, see Coarsen()
  // and Refine() ).
  vtkIdType GetNumberOfCells()
    {
      vtkIdType numCells=1;
      for(int i=0; i<3; i++)
        {
        numCells *= HiCorner[i] - LoCorner[i] + 1;
        }
      return numCells;
    }
  
  // Description:
  // Modify LoCorner and HiCorner by coarsening with the given
  // refinement ratio.
  // \pre valid_refinement: refinement>=2
  void Coarsen(int refinement)
    {
      assert("pre: valid_refinement" && refinement>=2);
      
      for (int i=0; i<3; i++)
        {
        this->LoCorner[i] =
          ( this->LoCorner[i] < 0 ?
            -abs(this->LoCorner[i]+1)/refinement - 1 :
            this->LoCorner[i]/refinement );
        this->HiCorner[i] =
          ( this->HiCorner[i] < 0 ?
            -abs(this->HiCorner[i]+1)/refinement - 1 :
            this->HiCorner[i]/refinement );
        }
    }
  
  // Description:
  // Modify LoCorner and HiCorner by refining with the given
  // refinement ratio.
  // \pre valid_refinement: refinement>=2
  void Refine(int refinement)
    {
      assert("pre: valid_refinement" && refinement>=2);
      
      for (int i=0; i<3; i++)
        {
        this->LoCorner[i] = this->LoCorner[i]*refinement;
        this->HiCorner[i] = (this->HiCorner[i]+1)*refinement-1;
        }
    }
  
  // Description:
  // Returns non-zero if the box contains the cell with
  // given indices.
  int DoesContainCell(int i, int j, int k)
    {
      return
        i >= this->LoCorner[0] && i <= this->HiCorner[0] &&
        j >= this->LoCorner[1] && j <= this->HiCorner[1] &&
        k >= this->LoCorner[2] && k <= this->HiCorner[2];
    }
  
  // Description:
  // Returns non-zero if the box contains `box`
  int DoesContainBox(vtkAMRBox const & box) const
    {
      // return DoesContainCell(box.LoCorner) && DoesContainCell(box.HiCorner);
      return box.LoCorner[0] >= this->LoCorner[0]
        && box.LoCorner[1] >= this->LoCorner[1]
        && box.LoCorner[2] >= this->LoCorner[2]
        && box.HiCorner[0] <= this->HiCorner[0]
        && box.HiCorner[1] <= this->HiCorner[1]
        && box.HiCorner[2] <= this->HiCorner[2];
    }
  
  // Description:
  // Print LoCorner and HiCorner
  void Print(ostream &os)
    {
      os << "LoCorner: " << this->LoCorner[0] << "," << this->LoCorner[1]
         << "," << this->LoCorner[2] << "\n";
      os << "HiCorner: " << this->HiCorner[0] << "," << this->HiCorner[1]
         << "," << this->HiCorner[2] << "\n";
    }
  
  // Description:
  // Check if cell position is HiCorner
  bool IsHiCorner(const int pos[3]) const
    {
      return this->HiCorner[0] == pos[0]
        && this->HiCorner[1] == pos[1]
        && this->HiCorner[2] == pos[2];
    }
  
  // Description:
  // Check if cell position is LoCorner
  bool IsLoCorner(const int pos[3]) const
    {
      return this->LoCorner[0] == pos[0]
        && this->LoCorner[1] == pos[1]
        && this->LoCorner[2] == pos[2];
    }  
};

#endif
