#ifndef _RAR_PPMMODEL_#define _RAR_PPMMODEL_#include "coder.hpp"#include "suballoc.hpp"const int MAX_O=64;                   /* maximum allowed model order */const int INT_BITS=7, PERIOD_BITS=7, TOT_BITS=INT_BITS+PERIOD_BITS,          INTERVAL=1 << INT_BITS, BIN_SCALE=1 << TOT_BITS, MAX_FREQ=124;#ifndef STRICT_ALIGNMENT_REQUIRED#pragma pack(1)#endifstruct SEE2_CONTEXT{ // SEE-contexts for PPM-contexts with masked symbols  ushort Summ;  byte Shift, Count;  void init(int InitVal)  {    Summ=InitVal << (Shift=PERIOD_BITS-4);    Count=4;  }  uint getMean()  {    uint RetVal=SHORT16(Summ) >> Shift;    Summ -= RetVal;    return RetVal+(RetVal == 0);  }  void update()  {    if (Shift < PERIOD_BITS && --Count == 0)    {      Summ += Summ;      Count=3 << Shift++;    }  }};class ModelPPM;struct PPM_CONTEXT;struct STATE{  byte Symbol;  byte Freq;  PPM_CONTEXT* Successor;};struct FreqData{  ushort SummFreq;  STATE _PACK_ATTR * Stats;};struct PPM_CONTEXT {    ushort NumStats;    union    {      FreqData U;      STATE OneState;    };    PPM_CONTEXT* Suffix;    inline void encodeBinSymbol(ModelPPM *Model,int symbol);  // MaxOrder:    inline void encodeSymbol1(ModelPPM *Model,int symbol);    //  ABCD    context    inline void encodeSymbol2(ModelPPM *Model,int symbol);    //   BCD    suffix    inline void decodeBinSymbol(ModelPPM *Model);  //   BCDE   successor    inline bool decodeSymbol1(ModelPPM *Model);    // other orders:    inline bool decodeSymbol2(ModelPPM *Model);    //   BCD    context    inline void update1(ModelPPM *Model,STATE* p); //    CD    suffix    inline void update2(ModelPPM *Model,STATE* p); //   BCDE   successor    void rescale(ModelPPM *Model);    inline PPM_CONTEXT* createChild(ModelPPM *Model,STATE* pStats,STATE& FirstState);    inline SEE2_CONTEXT* makeEscFreq2(ModelPPM *Model,int Diff);};#ifndef STRICT_ALIGNMENT_REQUIRED#ifdef _AIX#pragma pack(pop)#else#pragma pack()#endif#endifconst uint UNIT_SIZE=Max(sizeof(PPM_CONTEXT),sizeof(RAR_MEM_BLK));const uint FIXED_UNIT_SIZE=12;/*inline PPM_CONTEXT::PPM_CONTEXT(STATE* pStats,PPM_CONTEXT* ShorterContext):        NumStats(1), Suffix(ShorterContext) { pStats->Successor=this; }inline PPM_CONTEXT::PPM_CONTEXT(): NumStats(0) {}*/template <class T>inline void _PPMD_SWAP(T& t1,T& t2) { T tmp=t1; t1=t2; t2=tmp; }class ModelPPM{  private:    friend struct PPM_CONTEXT;        _PACK_ATTR SEE2_CONTEXT SEE2Cont[25][16], DummySEE2Cont;        struct PPM_CONTEXT *MinContext, *MedContext, *MaxContext;    STATE* FoundState;      // found next state transition    int NumMasked, InitEsc, OrderFall, MaxOrder, RunLength, InitRL;    byte CharMask[256], NS2Indx[256], NS2BSIndx[256], HB2Flag[256];    byte EscCount, PrevSuccess, HiBitsFlag;    ushort BinSumm[128][64];               // binary SEE-contexts    RangeCoder Coder;    SubAllocator SubAlloc;    void RestartModelRare();    void StartModelRare(int MaxOrder);    inline PPM_CONTEXT* CreateSuccessors(bool Skip,STATE* p1);    inline void UpdateModel();    inline void ClearMask();  public:    ModelPPM();    bool DecodeInit(Unpack *UnpackRead,int &EscChar);    int DecodeChar();};#endif