stridedstepper.cc

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#define AFF_STRIDEDSTEPPER_CC_VERSION \
  "AFF_STRIDEDSTEPPER_DEF_H   V1.2"

#include<aff/lib/stridedstepper.h>

namespace aff {

namespace util {

  StridedStepper::StridedStepper(const Strided& strided):
    Mshape(strided), Mcurrent(strided.first_offset()),
    Mindex(strided.first()), Mcarry(0), Mvalid(true),
    Mfirst_offset(strided.first_offset()),
    Mlast_offset(strided.last_offset())
    { 
      // calculate Mcarry
      for (Tsubscript i=0; i<(Tshape::Mmax_dimen); i++)
      { Mcarry[i]=strided.size(i)*strided.stride(i); }
    }

  /*----------------------------------------------------------------------*/

  StridedStepper& StridedStepper::incr()
    {
      if (!this->more()) Mvalid=false;
      Tsubscript i=0;
      while (i<Tshape::Mmax_dimen)
      {
        ++Mindex[i];
        Mcurrent+=Mshape.stride(i);
        if (Mindex[i]>Mshape.last(i)) 
        {
          Mindex[i]=Mshape.first(i);
          Mcurrent-=Mcarry[i];
          ++i;
        }
        else
        {
          i=Tshape::Mmax_dimen;
        }
      }
      return(*this);
    }

  /*----------------------------------------------------------------------*/

  StridedStepper& StridedStepper::decr()
    {
      if (!this->less()) Mvalid=false;
      Tsubscript i=0;
      while (i<Tshape::Mmax_dimen)
      {
        --Mindex[i];
        Mcurrent-=Mshape.stride(i);
        if (Mindex[i]<Mshape.first(i)) 
        {
          Mindex[i]=Mshape.last(i);
          Mcurrent+=Mcarry[i];
          ++i;
        }
        else
        {
          i=Tshape::Mmax_dimen;
        }
      }
      return(*this);
    }

} // namespace util

} // namespace aff

/* ----- END OF stridedstepper.cc ----- */