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#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;
#pragma pack(1)
struct 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++;
}
}
} _PACK_ATTR;
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);
};
#ifdef _AIX
#pragma pack(pop)
#else
#pragma pack()
#endif
const uint UNIT_SIZE=sizeof(PPM_CONTEXT);
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;
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
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