/* Ppmd7Enc.c -- PPMdH Encoder

2017-04-03 : Igor Pavlov : Public domain

This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */

#include "Precomp.h"

#include "Ppmd7.h"

#define kTopValue (1 << 24)

void Ppmd7z_RangeEnc_Init(CPpmd7z_RangeEnc *p)

{

  p->Low = 0;

  p->Range = 0xFFFFFFFF;

  p->Cache = 0;

  p->CacheSize = 1;

}

static void RangeEnc_ShiftLow(CPpmd7z_RangeEnc *p)

{

  if ((UInt32)p->Low < (UInt32)0xFF000000 || (unsigned)(p->Low >> 32) != 0)

  {

    Byte temp = p->Cache;

    do

    {

      IByteOut_Write(p->Stream, (Byte)(temp + (Byte)(p->Low >> 32)));

      temp = 0xFF;

    }

    while (--p->CacheSize != 0);

    p->Cache = (Byte)((UInt32)p->Low >> 24);

  }

  p->CacheSize++;

  p->Low = (UInt32)p->Low << 8;

}

static void RangeEnc_Encode(CPpmd7z_RangeEnc *p, UInt32 start, UInt32 size, UInt32 total)

{

  p->Low += start * (p->Range /= total);

  p->Range *= size;

  while (p->Range < kTopValue)

  {

    p->Range <<= 8;

    RangeEnc_ShiftLow(p);

  }

}

static void RangeEnc_EncodeBit_0(CPpmd7z_RangeEnc *p, UInt32 size0)

{

  p->Range = (p->Range >> 14) * size0;

  while (p->Range < kTopValue)

  {

    p->Range <<= 8;

    RangeEnc_ShiftLow(p);

  }

}

static void RangeEnc_EncodeBit_1(CPpmd7z_RangeEnc *p, UInt32 size0)

{

  UInt32 newBound = (p->Range >> 14) * size0;

  p->Low += newBound;

  p->Range -= newBound;

  while (p->Range < kTopValue)

  {

    p->Range <<= 8;

    RangeEnc_ShiftLow(p);

  }

}

void Ppmd7z_RangeEnc_FlushData(CPpmd7z_RangeEnc *p)

{

  unsigned i;

  for (i = 0; i < 5; i++)

    RangeEnc_ShiftLow(p);

}

#define MASK(sym) ((signed char *)charMask)[sym]

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

{

  size_t charMask[256 / sizeof(size_t)];

  if (p->MinContext->NumStats != 1)

  {

    CPpmd_State *s = Ppmd7_GetStats(p, p->MinContext);

    UInt32 sum;

    unsigned i;

    if (s->Symbol == symbol)

    {

      RangeEnc_Encode(rc, 0, s->Freq, p->MinContext->SummFreq);

      p->FoundState = s;

      Ppmd7_Update1_0(p);

      return;

    }

    p->PrevSuccess = 0;

    sum = s->Freq;

    i = p->MinContext->NumStats - 1;

    do

    {

      if ((++s)->Symbol == symbol)

      {

        RangeEnc_Encode(rc, sum, s->Freq, p->MinContext->SummFreq);

        p->FoundState = s;

        Ppmd7_Update1(p);

        return;

      }

      sum += s->Freq;

    }

    while (--i);

    p->HiBitsFlag = p->HB2Flag[p->FoundState->Symbol];

    PPMD_SetAllBitsIn256Bytes(charMask);

    MASK(s->Symbol) = 0;

    i = p->MinContext->NumStats - 1;

    do { MASK((--s)->Symbol) = 0; } while (--i);

    RangeEnc_Encode(rc, sum, p->MinContext->SummFreq - sum, p->MinContext->SummFreq);

  }

  else

  {

    UInt16 *prob = Ppmd7_GetBinSumm(p);

    CPpmd_State *s = Ppmd7Context_OneState(p->MinContext);

    if (s->Symbol == symbol)

    {

      RangeEnc_EncodeBit_0(rc, *prob);

      *prob = (UInt16)PPMD_UPDATE_PROB_0(*prob);

      p->FoundState = s;

      Ppmd7_UpdateBin(p);

      return;

    }

    else

    {

      RangeEnc_EncodeBit_1(rc, *prob);

      *prob = (UInt16)PPMD_UPDATE_PROB_1(*prob);

      p->InitEsc = PPMD7_kExpEscape[*prob >> 10];

      PPMD_SetAllBitsIn256Bytes(charMask);

      MASK(s->Symbol) = 0;

      p->PrevSuccess = 0;

    }

  }

  for (;;)

  {

    UInt32 escFreq;

    CPpmd_See *see;

    CPpmd_State *s;

    UInt32 sum;

    unsigned i, numMasked = p->MinContext->NumStats;

    do

    {

      p->OrderFall++;

      if (!p->MinContext->Suffix)

        return; /* EndMarker (symbol = -1) */

      p->MinContext = Ppmd7_GetContext(p, p->MinContext->Suffix);

    }

    while (p->MinContext->NumStats == numMasked);

    see = Ppmd7_MakeEscFreq(p, numMasked, &escFreq);

    s = Ppmd7_GetStats(p, p->MinContext);

    sum = 0;

    i = p->MinContext->NumStats;

    do

    {

      int cur = s->Symbol;

      if (cur == symbol)

      {

        UInt32 low = sum;

        CPpmd_State *s1 = s;

        do

        {

          sum += (s->Freq & (int)(MASK(s->Symbol)));

          s++;

        }

        while (--i);

        RangeEnc_Encode(rc, low, s1->Freq, sum + escFreq);

        Ppmd_See_Update(see);

        p->FoundState = s1;

        Ppmd7_Update2(p);

        return;

      }

      sum += (s->Freq & (int)(MASK(cur)));

      MASK(cur) = 0;

      s++;

    }

    while (--i);

    RangeEnc_Encode(rc, sum, escFreq, sum + escFreq);

    see->Summ = (UInt16)(see->Summ + sum + escFreq);

  }

}