QuietUnrar/libunrar/model.hpp

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#ifndef _RAR_PPMMODEL_
#define _RAR_PPMMODEL_
#include "coder.hpp"
#include "suballoc.hpp"
#ifdef ALLOW_MISALIGNED
#pragma pack(1)
#endif
struct RARPPM_DEF
{
static 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;
};
struct RARPPM_SEE2_CONTEXT : RARPPM_DEF
{ // 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=GET_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 RARPPM_CONTEXT;
struct RARPPM_STATE
{
byte Symbol;
byte Freq;
RARPPM_CONTEXT* Successor;
};
struct RARPPM_CONTEXT : RARPPM_DEF
{
ushort NumStats;
struct FreqData
{
ushort SummFreq;
RARPPM_STATE RARPPM_PACK_ATTR * Stats;
};
union
{
FreqData U;
RARPPM_STATE OneState;
};
RARPPM_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,RARPPM_STATE* p); // CD suffix
inline void update2(ModelPPM *Model,RARPPM_STATE* p); // BCDE successor
void rescale(ModelPPM *Model);
inline RARPPM_CONTEXT* createChild(ModelPPM *Model,RARPPM_STATE* pStats,RARPPM_STATE& FirstState);
inline RARPPM_SEE2_CONTEXT* makeEscFreq2(ModelPPM *Model,int Diff);
};
#ifdef ALLOW_MISALIGNED
#ifdef _AIX
#pragma pack(pop)
#else
#pragma pack()
#endif
#endif
class ModelPPM : RARPPM_DEF
{
private:
friend struct RARPPM_CONTEXT;
RARPPM_SEE2_CONTEXT SEE2Cont[25][16], DummySEE2Cont;
struct RARPPM_CONTEXT *MinContext, *MedContext, *MaxContext;
RARPPM_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 RARPPM_CONTEXT* CreateSuccessors(bool Skip,RARPPM_STATE* p1);
inline void UpdateModel();
inline void ClearMask();
public:
ModelPPM();
void CleanUp(); // reset PPM variables after data error
bool DecodeInit(Unpack *UnpackRead,int &EscChar);
int DecodeChar();
};
#endif