/* Ppmd8Enc.c -- Ppmd8 (PPMdI) Encoder

2023-09-07 : Igor Pavlov : Public domain

This code is based on:

  PPMd var.I (2002): Dmitry Shkarin : Public domain

  Carryless rangecoder (1999): Dmitry Subbotin : Public domain */

#include "Precomp.h"

#include "Ppmd8.h"

#define kTop ((UInt32)1 << 24)

#define kBot ((UInt32)1 << 15)

#define WRITE_BYTE(p) IByteOut_Write(p->Stream.Out, (Byte)(p->Low >> 24))

void Ppmd8_Flush_RangeEnc(CPpmd8 *p)

{

  unsigned i;

  for (i = 0; i < 4; i++, p->Low <<= 8 )

    WRITE_BYTE(p);

}

#define RC_NORM(p) \

  while ((p->Low ^ (p->Low + p->Range)) < kTop \

    || (p->Range < kBot && ((p->Range = (0 - p->Low) & (kBot - 1)), 1))) \

    { WRITE_BYTE(p); p->Range <<= 8; p->Low <<= 8; }

// we must use only one type of Normalization from two: LOCAL or REMOTE

#define RC_NORM_LOCAL(p)    // RC_NORM(p)

#define RC_NORM_REMOTE(p)   RC_NORM(p)

// #define RC_PRE(total) p->Range /= total;

// #define RC_PRE(total)

#define R p

Z7_FORCE_INLINE

// Z7_NO_INLINE

static void Ppmd8_RangeEnc_Encode(CPpmd8 *p, UInt32 start, UInt32 size, UInt32 total)

{

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

  R->Range *= size;

  RC_NORM_LOCAL(R)

}

#define RC_Encode(start, size, total)  Ppmd8_RangeEnc_Encode(p, start, size, total);

#define RC_EncodeFinal(start, size, total)  RC_Encode(start, size, total)  RC_NORM_REMOTE(p)

#define CTX(ref) ((CPpmd8_Context *)Ppmd8_GetContext(p, ref))

// typedef CPpmd8_Context * CTX_PTR;

#define SUCCESSOR(p) Ppmd_GET_SUCCESSOR(p)

void Ppmd8_UpdateModel(CPpmd8 *p);

#define MASK(sym)  ((Byte *)charMask)[sym]

// Z7_FORCE_INLINE

// static

void Ppmd8_EncodeSymbol(CPpmd8 *p, int symbol)

{

  size_t charMask[256 / sizeof(size_t)];

  if (p->MinContext->NumStats != 0)

  {

    CPpmd_State *s = Ppmd8_GetStats(p, p->MinContext);

    UInt32 sum;

    unsigned i;

    UInt32 summFreq = p->MinContext->Union2.SummFreq;

    PPMD8_CORRECT_SUM_RANGE(p, summFreq)

    // RC_PRE(summFreq);

    if (s->Symbol == symbol)

    {

      RC_EncodeFinal(0, s->Freq, summFreq)

      p->FoundState = s;

      Ppmd8_Update1_0(p);

      return;

    }

    p->PrevSuccess = 0;

    sum = s->Freq;

    i = p->MinContext->NumStats;

    do

    {

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

      {

        RC_EncodeFinal(sum, s->Freq, summFreq)

        p->FoundState = s;

        Ppmd8_Update1(p);

        return;

      }

      sum += s->Freq;

    }

    while (--i);

    RC_Encode(sum, summFreq - sum, summFreq)

    PPMD_SetAllBitsIn256Bytes(charMask)

    // MASK(s->Symbol) = 0;

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

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

    {

      CPpmd_State *s2 = Ppmd8_GetStats(p, p->MinContext);

      MASK(s->Symbol) = 0;

      do

      {

        const unsigned sym0 = s2[0].Symbol;

        const unsigned sym1 = s2[1].Symbol;

        s2 += 2;

        MASK(sym0) = 0;

        MASK(sym1) = 0;

      }

      while (s2 < s);

    }

  }

  else

  {

    UInt16 *prob = Ppmd8_GetBinSumm(p);

    CPpmd_State *s = Ppmd8Context_OneState(p->MinContext);

    UInt32 pr = *prob;

    const UInt32 bound = (R->Range >> 14) * pr;

    pr = PPMD_UPDATE_PROB_1(pr);

    if (s->Symbol == symbol)

    {

      *prob = (UInt16)(pr + (1 << PPMD_INT_BITS));

      // RangeEnc_EncodeBit_0(p, bound);

      R->Range = bound;

      RC_NORM(R)

      // p->FoundState = s;

      // Ppmd8_UpdateBin(p);

      {

        const unsigned freq = s->Freq;

        CPpmd8_Context *c = CTX(SUCCESSOR(s));

        p->FoundState = s;

        p->PrevSuccess = 1;

        p->RunLength++;

        s->Freq = (Byte)(freq + (freq < 196)); // Ppmd8 (196)

        // NextContext(p);

        if (p->OrderFall == 0 && (const Byte *)c >= p->UnitsStart)

          p->MaxContext = p->MinContext = c;

        else

          Ppmd8_UpdateModel(p);

      }

      return;

    }

    *prob = (UInt16)pr;

    p->InitEsc = p->ExpEscape[pr >> 10];

    // RangeEnc_EncodeBit_1(p, bound);

    R->Low += bound;

    R->Range = (R->Range & ~((UInt32)PPMD_BIN_SCALE - 1)) - bound;

    RC_NORM_LOCAL(R)

    PPMD_SetAllBitsIn256Bytes(charMask)

    MASK(s->Symbol) = 0;

    p->PrevSuccess = 0;

  }

  for (;;)

  {

    CPpmd_See *see;

    CPpmd_State *s;

    UInt32 sum, escFreq;

    CPpmd8_Context *mc;

    unsigned i, numMasked;

    RC_NORM_REMOTE(p)

    mc = p->MinContext;

    numMasked = mc->NumStats;

    do

    {

      p->OrderFall++;

      if (!mc->Suffix)

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

      mc = Ppmd8_GetContext(p, mc->Suffix);

    }

    while (mc->NumStats == numMasked);

    p->MinContext = mc;

    see = Ppmd8_MakeEscFreq(p, numMasked, &escFreq);

    s = Ppmd8_GetStats(p, p->MinContext);

    sum = 0;

    i = (unsigned)p->MinContext->NumStats + 1;

    do

    {

      const unsigned cur = s->Symbol;

      if ((int)cur == symbol)

      {

        const UInt32 low = sum;

        const UInt32 freq = s->Freq;

        unsigned num2;

        Ppmd_See_UPDATE(see)

        p->FoundState = s;

        sum += escFreq;

        num2 = i / 2;

        i &= 1;

        sum += freq & (0 - (UInt32)i);

        if (num2 != 0)

        {

          s += i;

          do

          {

            const unsigned sym0 = s[0].Symbol;

            const unsigned sym1 = s[1].Symbol;

            s += 2;

            sum += (s[-2].Freq & (unsigned)(MASK(sym0)));

            sum += (s[-1].Freq & (unsigned)(MASK(sym1)));

          }

          while (--num2);

        }

        PPMD8_CORRECT_SUM_RANGE(p, sum)

        RC_EncodeFinal(low, freq, sum)

        Ppmd8_Update2(p);

        return;

      }

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

      s++;

    }

    while (--i);

    {

      UInt32 total = sum + escFreq;

      see->Summ = (UInt16)(see->Summ + total);

      PPMD8_CORRECT_SUM_RANGE(p, total)

      RC_Encode(sum, total - sum, total)

    }

    {

      const CPpmd_State *s2 = Ppmd8_GetStats(p, p->MinContext);

      s--;

      MASK(s->Symbol) = 0;

      do

      {

        const unsigned sym0 = s2[0].Symbol;

        const unsigned sym1 = s2[1].Symbol;

        s2 += 2;

        MASK(sym0) = 0;

        MASK(sym1) = 0;

      }

      while (s2 < s);

    }

  }

}

#undef kTop

#undef kBot

#undef WRITE_BYTE

#undef RC_NORM_BASE

#undef RC_NORM_1

#undef RC_NORM

#undef RC_NORM_LOCAL

#undef RC_NORM_REMOTE

#undef R

#undef RC_Encode

#undef RC_EncodeFinal

#undef CTX

#undef SUCCESSOR

#undef MASK