/* Ppmd7.h -- PPMdH compression codec
2017-04-03 : Igor Pavlov : Public domain
This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */

/* This code supports the implementation of RangeCoder from 7z,
 * instead of RangeCoder from original PPMd var.H.
 */

#ifndef __PPMD7_H
#define __PPMD7_H

#include "Ppmd.h"

#define PPMD7_MIN_ORDER 2
#define PPMD7_MAX_ORDER 64

#define PPMD7_MIN_MEM_SIZE (1 << 11)
#define PPMD7_MAX_MEM_SIZE (0xFFFFFFFF - 12 * 3)

struct CPpmd7_Context_;

typedef
  #ifdef PPMD_32BIT
    struct CPpmd7_Context_ *
  #else
    UInt32
  #endif
  CPpmd7_Context_Ref;

typedef struct CPpmd7_Context_
{
  UInt16 NumStats;
  UInt16 SummFreq;
  CPpmd_State_Ref Stats;
  CPpmd7_Context_Ref Suffix;
} CPpmd7_Context;

#define Ppmd7Context_OneState(p) ((CPpmd_State *)&(p)->SummFreq)

typedef struct
{
  CPpmd7_Context *MinContext, *MaxContext;
  CPpmd_State *FoundState;
  unsigned OrderFall, InitEsc, PrevSuccess, MaxOrder, HiBitsFlag;
  Int32 RunLength, InitRL; /* must be 32-bit at least */

  UInt32 Size;
  UInt32 GlueCount;
  Byte *Base, *LoUnit, *HiUnit, *Text, *UnitsStart;
  UInt32 AlignOffset;

  Byte Indx2Units[PPMD_NUM_INDEXES];
  Byte Units2Indx[128];
  CPpmd_Void_Ref FreeList[PPMD_NUM_INDEXES];
  Byte NS2Indx[256], NS2BSIndx[256], HB2Flag[256];
  CPpmd_See DummySee, See[25][16];
  UInt16 BinSumm[128][64];
} CPpmd7;

void Ppmd7_Construct(CPpmd7 *p);
Bool Ppmd7_Alloc(CPpmd7 *p, UInt32 size, ISzAllocPtr alloc);
void Ppmd7_Free(CPpmd7 *p, ISzAllocPtr alloc);
void Ppmd7_Init(CPpmd7 *p, unsigned maxOrder);
#define Ppmd7_WasAllocated(p) ((p)->Base != NULL)


/* ---------- Internal Functions ---------- */

extern const Byte PPMD7_kExpEscape[16];

#ifdef PPMD_32BIT
  #define Ppmd7_GetPtr(p, ptr) (ptr)
  #define Ppmd7_GetContext(p, ptr) (ptr)
  #define Ppmd7_GetStats(p, ctx) ((ctx)->Stats)
#else
  #define Ppmd7_GetPtr(p, offs) ((void *)((p)->Base + (offs)))
  #define Ppmd7_GetContext(p, offs) ((CPpmd7_Context *)Ppmd7_GetPtr((p), (offs)))
  #define Ppmd7_GetStats(p, ctx) ((CPpmd_State *)Ppmd7_GetPtr((p), ((ctx)->Stats)))
#endif

void Ppmd7_Update1(CPpmd7 *p);
void Ppmd7_Update1_0(CPpmd7 *p);
void Ppmd7_Update2(CPpmd7 *p);
void Ppmd7_UpdateBin(CPpmd7 *p);

#define Ppmd7_GetBinSumm(p) \
    &p->BinSumm[(size_t)(unsigned)Ppmd7Context_OneState(p->MinContext)->Freq - 1][p->PrevSuccess + \
    p->NS2BSIndx[(size_t)Ppmd7_GetContext(p, p->MinContext->Suffix)->NumStats - 1] + \
    (p->HiBitsFlag = p->HB2Flag[p->FoundState->Symbol]) + \
    2 * p->HB2Flag[(unsigned)Ppmd7Context_OneState(p->MinContext)->Symbol] + \
    ((p->RunLength >> 26) & 0x20)]

CPpmd_See *Ppmd7_MakeEscFreq(CPpmd7 *p, unsigned numMasked, UInt32 *scale);


/* ---------- Decode ---------- */

typedef struct
{
  UInt32 Range;
  UInt32 Code;
  IByteIn *Stream;
} CPpmd7z_RangeDec;

void Ppmd7z_RangeDec_CreateVTable(CPpmd7z_RangeDec *p);
Bool Ppmd7z_RangeDec_Init(CPpmd7z_RangeDec *p);
#define Ppmd7z_RangeDec_IsFinishedOK(p) ((p)->Code == 0)

int Ppmd7_DecodeSymbol(CPpmd7 *p, CPpmd7z_RangeDec *rc);


/* ---------- Encode ---------- */

typedef struct
{
  UInt64 Low;
  UInt32 Range;
  Byte Cache;
  UInt64 CacheSize;
  IByteOut *Stream;
} CPpmd7z_RangeEnc;

void Ppmd7z_RangeEnc_Init(CPpmd7z_RangeEnc *p);
void Ppmd7z_RangeEnc_FlushData(CPpmd7z_RangeEnc *p);

void Ppmd7_EncodeSymbol(CPpmd7 *p, CPpmd7z_RangeEnc *rc, int symbol);

#endif
