AMReX_BoxIterator.H

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#ifndef AMREX_BOXITERATOR_H_
#define AMREX_BOXITERATOR_H_
#include <AMReX_Config.H>
 
#include <AMReX_BLassert.H>
#include <AMReX_Box.H>
#include <AMReX_REAL.H>
#include <AMReX_SPACE.H>
#include <AMReX_IntVect.H>
 
#include <cstdlib>
 
namespace amrex
{
  class BoxIterator
  {
  public:
 
    BoxIterator () noexcept = default;
 
 
    explicit BoxIterator (const Box& a_bx) noexcept;
 
    void setBox (const Box& a_bx) noexcept;
 
 
    void define (const Box& a_bx) noexcept;
 
 
    void begin () noexcept;
 
 
    void reset () noexcept;
 
 
    void operator ++ () noexcept;
 
    void next () noexcept;
 
 
    [[nodiscard]] const IntVect& operator () () const noexcept;
 
 
    [[nodiscard]] bool ok () noexcept;
 
  protected:
    IntVect m_current = IntVect::TheUnitVector();
    IntVect m_boxLo   = IntVect::TheUnitVector();
    IntVect m_boxHi   = IntVect::TheZeroVector();
  };
 
  inline
  BoxIterator::BoxIterator (const Box& a_bx) noexcept
  {
    define(a_bx);
  }
 
  inline
  void BoxIterator::begin () noexcept
  {
    if (m_boxLo <= m_boxHi) { m_current = m_boxLo; }
  }
 
  inline
  void BoxIterator::reset () noexcept
  {
    begin();
  }
 
  inline
  void BoxIterator::operator ++ () noexcept
  {
    next();
  }
 
  inline
  void BoxIterator::next () noexcept
  {
    m_current[0]++;
#if AMREX_SPACEDIM >= 2
    if (m_current[0] > m_boxHi[0])
      {
        m_current[0] = m_boxLo[0];
        m_current[1]++;
#if AMREX_SPACEDIM >= 3
        if (m_current[1] > m_boxHi[1])
          {
            m_current[1] = m_boxLo[1];
            m_current[2]++;
          }
#endif
      }
#endif
  }
 
  inline
  const IntVect& BoxIterator::operator () () const noexcept
  {
    BL_ASSERT(m_current <= m_boxHi);
    BL_ASSERT(m_current >= m_boxLo);
    return m_current;
  }
 
  inline
  bool BoxIterator::ok () noexcept
  {
    return (m_current  <= m_boxHi);
  }
}
#endif