123 lines
3.0 KiB
C++
123 lines
3.0 KiB
C++
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#ifndef _RAR_PPMMODEL_
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#define _RAR_PPMMODEL_
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#include "coder.hpp"
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#include "suballoc.hpp"
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#ifdef ALLOW_MISALIGNED
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#pragma pack(1)
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#endif
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struct RARPPM_DEF
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{
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static const int INT_BITS=7, PERIOD_BITS=7, TOT_BITS=INT_BITS+PERIOD_BITS,
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INTERVAL=1 << INT_BITS, BIN_SCALE=1 << TOT_BITS, MAX_FREQ=124;
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};
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struct RARPPM_SEE2_CONTEXT : RARPPM_DEF
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{ // SEE-contexts for PPM-contexts with masked symbols
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ushort Summ;
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byte Shift, Count;
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void init(int InitVal)
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{
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Summ=InitVal << (Shift=PERIOD_BITS-4);
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Count=4;
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}
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uint getMean()
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{
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uint RetVal=GET_SHORT16(Summ) >> Shift;
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Summ -= RetVal;
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return RetVal+(RetVal == 0);
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}
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void update()
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{
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if (Shift < PERIOD_BITS && --Count == 0)
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{
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Summ += Summ;
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Count=3 << Shift++;
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}
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}
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};
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class ModelPPM;
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struct RARPPM_CONTEXT;
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struct RARPPM_STATE
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{
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byte Symbol;
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byte Freq;
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RARPPM_CONTEXT* Successor;
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};
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struct RARPPM_CONTEXT : RARPPM_DEF
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{
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ushort NumStats;
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struct FreqData
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{
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ushort SummFreq;
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RARPPM_STATE RARPPM_PACK_ATTR * Stats;
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};
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union
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{
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FreqData U;
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RARPPM_STATE OneState;
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};
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RARPPM_CONTEXT* Suffix;
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inline void encodeBinSymbol(ModelPPM *Model,int symbol); // MaxOrder:
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inline void encodeSymbol1(ModelPPM *Model,int symbol); // ABCD context
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inline void encodeSymbol2(ModelPPM *Model,int symbol); // BCD suffix
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inline void decodeBinSymbol(ModelPPM *Model); // BCDE successor
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inline bool decodeSymbol1(ModelPPM *Model); // other orders:
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inline bool decodeSymbol2(ModelPPM *Model); // BCD context
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inline void update1(ModelPPM *Model,RARPPM_STATE* p); // CD suffix
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inline void update2(ModelPPM *Model,RARPPM_STATE* p); // BCDE successor
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void rescale(ModelPPM *Model);
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inline RARPPM_CONTEXT* createChild(ModelPPM *Model,RARPPM_STATE* pStats,RARPPM_STATE& FirstState);
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inline RARPPM_SEE2_CONTEXT* makeEscFreq2(ModelPPM *Model,int Diff);
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};
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#ifdef ALLOW_MISALIGNED
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#ifdef _AIX
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#pragma pack(pop)
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#else
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#pragma pack()
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#endif
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#endif
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class ModelPPM : RARPPM_DEF
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{
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private:
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friend struct RARPPM_CONTEXT;
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RARPPM_SEE2_CONTEXT SEE2Cont[25][16], DummySEE2Cont;
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struct RARPPM_CONTEXT *MinContext, *MedContext, *MaxContext;
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RARPPM_STATE* FoundState; // found next state transition
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int NumMasked, InitEsc, OrderFall, MaxOrder, RunLength, InitRL;
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byte CharMask[256], NS2Indx[256], NS2BSIndx[256], HB2Flag[256];
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byte EscCount, PrevSuccess, HiBitsFlag;
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ushort BinSumm[128][64]; // binary SEE-contexts
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RangeCoder Coder;
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SubAllocator SubAlloc;
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void RestartModelRare();
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void StartModelRare(int MaxOrder);
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inline RARPPM_CONTEXT* CreateSuccessors(bool Skip,RARPPM_STATE* p1);
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inline void UpdateModel();
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inline void ClearMask();
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public:
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ModelPPM();
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void CleanUp(); // reset PPM variables after data error
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bool DecodeInit(Unpack *UnpackRead,int &EscChar);
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int DecodeChar();
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};
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#endif
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