tor-browser

The Tor Browser
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Ppmd7.h (3963B)

      1 /* Ppmd7.h -- PPMdH compression codec
      2 2017-04-03 : Igor Pavlov : Public domain
      3 This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */
      4 
      5 /* This code supports virtual RangeDecoder and includes the implementation
      6 of RangeCoder from 7z, instead of RangeCoder from original PPMd var.H.
      7 If you need the compatibility with original PPMd var.H, you can use external RangeDecoder */
      8 
      9 #ifndef __PPMD7_H
     10 #define __PPMD7_H
     11 
     12 #include "Ppmd.h"
     13 
     14 EXTERN_C_BEGIN
     15 
     16 #define PPMD7_MIN_ORDER 2
     17 #define PPMD7_MAX_ORDER 64
     18 
     19 #define PPMD7_MIN_MEM_SIZE (1 << 11)
     20 #define PPMD7_MAX_MEM_SIZE (0xFFFFFFFF - 12 * 3)
     21 
     22 struct CPpmd7_Context_;
     23 
     24 typedef
     25  #ifdef PPMD_32BIT
     26    struct CPpmd7_Context_ *
     27  #else
     28    UInt32
     29  #endif
     30  CPpmd7_Context_Ref;
     31 
     32 typedef struct CPpmd7_Context_
     33 {
     34  UInt16 NumStats;
     35  UInt16 SummFreq;
     36  CPpmd_State_Ref Stats;
     37  CPpmd7_Context_Ref Suffix;
     38 } CPpmd7_Context;
     39 
     40 #define Ppmd7Context_OneState(p) ((CPpmd_State *)&(p)->SummFreq)
     41 
     42 typedef struct
     43 {
     44  CPpmd7_Context *MinContext, *MaxContext;
     45  CPpmd_State *FoundState;
     46  unsigned OrderFall, InitEsc, PrevSuccess, MaxOrder, HiBitsFlag;
     47  Int32 RunLength, InitRL; /* must be 32-bit at least */
     48 
     49  UInt32 Size;
     50  UInt32 GlueCount;
     51  Byte *Base, *LoUnit, *HiUnit, *Text, *UnitsStart;
     52  UInt32 AlignOffset;
     53 
     54  Byte Indx2Units[PPMD_NUM_INDEXES];
     55  Byte Units2Indx[128];
     56  CPpmd_Void_Ref FreeList[PPMD_NUM_INDEXES];
     57  Byte NS2Indx[256], NS2BSIndx[256], HB2Flag[256];
     58  CPpmd_See DummySee, See[25][16];
     59  UInt16 BinSumm[128][64];
     60 } CPpmd7;
     61 
     62 void Ppmd7_Construct(CPpmd7 *p);
     63 Bool Ppmd7_Alloc(CPpmd7 *p, UInt32 size, ISzAllocPtr alloc);
     64 void Ppmd7_Free(CPpmd7 *p, ISzAllocPtr alloc);
     65 void Ppmd7_Init(CPpmd7 *p, unsigned maxOrder);
     66 #define Ppmd7_WasAllocated(p) ((p)->Base != NULL)
     67 
     68 
     69 /* ---------- Internal Functions ---------- */
     70 
     71 extern const Byte PPMD7_kExpEscape[16];
     72 
     73 #ifdef PPMD_32BIT
     74  #define Ppmd7_GetPtr(p, ptr) (ptr)
     75  #define Ppmd7_GetContext(p, ptr) (ptr)
     76  #define Ppmd7_GetStats(p, ctx) ((ctx)->Stats)
     77 #else
     78  #define Ppmd7_GetPtr(p, offs) ((void *)((p)->Base + (offs)))
     79  #define Ppmd7_GetContext(p, offs) ((CPpmd7_Context *)Ppmd7_GetPtr((p), (offs)))
     80  #define Ppmd7_GetStats(p, ctx) ((CPpmd_State *)Ppmd7_GetPtr((p), ((ctx)->Stats)))
     81 #endif
     82 
     83 void Ppmd7_Update1(CPpmd7 *p);
     84 void Ppmd7_Update1_0(CPpmd7 *p);
     85 void Ppmd7_Update2(CPpmd7 *p);
     86 void Ppmd7_UpdateBin(CPpmd7 *p);
     87 
     88 #define Ppmd7_GetBinSumm(p) \
     89    &p->BinSumm[(size_t)(unsigned)Ppmd7Context_OneState(p->MinContext)->Freq - 1][p->PrevSuccess + \
     90    p->NS2BSIndx[(size_t)Ppmd7_GetContext(p, p->MinContext->Suffix)->NumStats - 1] + \
     91    (p->HiBitsFlag = p->HB2Flag[p->FoundState->Symbol]) + \
     92    2 * p->HB2Flag[(unsigned)Ppmd7Context_OneState(p->MinContext)->Symbol] + \
     93    ((p->RunLength >> 26) & 0x20)]
     94 
     95 CPpmd_See *Ppmd7_MakeEscFreq(CPpmd7 *p, unsigned numMasked, UInt32 *scale);
     96 
     97 
     98 /* ---------- Decode ---------- */
     99 
    100 typedef struct IPpmd7_RangeDec IPpmd7_RangeDec;
    101 
    102 struct IPpmd7_RangeDec
    103 {
    104  UInt32 (*GetThreshold)(const IPpmd7_RangeDec *p, UInt32 total);
    105  void (*Decode)(const IPpmd7_RangeDec *p, UInt32 start, UInt32 size);
    106  UInt32 (*DecodeBit)(const IPpmd7_RangeDec *p, UInt32 size0);
    107 };
    108 
    109 typedef struct
    110 {
    111  IPpmd7_RangeDec vt;
    112  UInt32 Range;
    113  UInt32 Code;
    114  IByteIn *Stream;
    115 } CPpmd7z_RangeDec;
    116 
    117 void Ppmd7z_RangeDec_CreateVTable(CPpmd7z_RangeDec *p);
    118 Bool Ppmd7z_RangeDec_Init(CPpmd7z_RangeDec *p);
    119 #define Ppmd7z_RangeDec_IsFinishedOK(p) ((p)->Code == 0)
    120 
    121 int Ppmd7_DecodeSymbol(CPpmd7 *p, const IPpmd7_RangeDec *rc);
    122 
    123 
    124 /* ---------- Encode ---------- */
    125 
    126 typedef struct
    127 {
    128  UInt64 Low;
    129  UInt32 Range;
    130  Byte Cache;
    131  UInt64 CacheSize;
    132  IByteOut *Stream;
    133 } CPpmd7z_RangeEnc;
    134 
    135 void Ppmd7z_RangeEnc_Init(CPpmd7z_RangeEnc *p);
    136 void Ppmd7z_RangeEnc_FlushData(CPpmd7z_RangeEnc *p);
    137 
    138 void Ppmd7_EncodeSymbol(CPpmd7 *p, CPpmd7z_RangeEnc *rc, int symbol);
    139 
    140 EXTERN_C_END
    141 
    142 #endif