Method rescale

Libraries/unrar/model.cpp:119–168

void RARPPM_CONTEXT::rescale(ModelPPM *Model)
{
  int OldNS=NumStats, i=NumStats-1, Adder, EscFreq;
  RARPPM_STATE* p1, * p;
  for (p=Model->FoundState;p != U.Stats;p--)
    _PPMD_SWAP(p[0],p[-1]);
  U.Stats->Freq += 4;
  U.SummFreq += 4;
  EscFreq=U.SummFreq-p->Freq;
  Adder=(Model->OrderFall != 0);
  U.SummFreq = (p->Freq=(p->Freq+Adder) >> 1);
  do 
  {
    EscFreq -= (++p)->Freq;
    U.SummFreq += (p->Freq=(p->Freq+Adder) >> 1);
    if (p[0].Freq > p[-1].Freq) 
    {
      RARPPM_STATE tmp=*(p1=p);
      do 
      { 
        p1[0]=p1[-1]; 
      } while (--p1 != U.Stats && tmp.Freq > p1[-1].Freq);
      *p1=tmp;
    }
  } while ( --i );
  if (p->Freq == 0) 
  {
    do 
    { 
      i++; 
    } while ((--p)->Freq == 0);
    EscFreq += i;
    if ((NumStats -= i) == 1) 
    {
      RARPPM_STATE tmp=*U.Stats;
      do 
      { 
        tmp.Freq-=(tmp.Freq >> 1); 
        EscFreq>>=1; 
      } while (EscFreq > 1);
      Model->SubAlloc.FreeUnits(U.Stats,(OldNS+1) >> 1);
      *(Model->FoundState=&OneState)=tmp;  return;
    }
  }
  U.SummFreq += (EscFreq -= (EscFreq >> 1));
  int n0=(OldNS+1) >> 1, n1=(NumStats+1) >> 1;
  if (n0 != n1)
    U.Stats = (RARPPM_STATE*) Model->SubAlloc.ShrinkUnits(U.Stats,n0,n1);
  Model->FoundState=U.Stats;
}


inline RARPPM_CONTEXT* ModelPPM::CreateSuccessors(bool Skip,RARPPM_STATE* p1)