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hashcat/deps/LZMA-SDK/C/Ppmd7Dec.c

298 lines
7.1 KiB
C

/* Ppmd7Dec.c -- Ppmd7z (PPMdH with 7z Range Coder) Decoder
2021-04-13 : 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)
#define READ_BYTE(p) IByteIn_Read((p)->Stream)
BoolInt Ppmd7z_RangeDec_Init(CPpmd7_RangeDec *p)
{
unsigned i;
p->Code = 0;
p->Range = 0xFFFFFFFF;
if (READ_BYTE(p) != 0)
return False;
for (i = 0; i < 4; i++)
p->Code = (p->Code << 8) | READ_BYTE(p);
return (p->Code < 0xFFFFFFFF);
}
#define RC_NORM_BASE(p) if ((p)->Range < kTopValue) \
{ (p)->Code = ((p)->Code << 8) | READ_BYTE(p); (p)->Range <<= 8;
#define RC_NORM_1(p) RC_NORM_BASE(p) }
#define RC_NORM(p) RC_NORM_BASE(p) RC_NORM_BASE(p) }}
// 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 R (&p->rc.dec)
MY_FORCE_INLINE
// MY_NO_INLINE
static void RangeDec_Decode(CPpmd7 *p, UInt32 start, UInt32 size)
{
R->Code -= start * R->Range;
R->Range *= size;
RC_NORM_LOCAL(R)
}
#define RC_Decode(start, size) RangeDec_Decode(p, start, size);
#define RC_DecodeFinal(start, size) RC_Decode(start, size) RC_NORM_REMOTE(R)
#define RC_GetThreshold(total) (R->Code / (R->Range /= (total)))
#define CTX(ref) ((CPpmd7_Context *)Ppmd7_GetContext(p, ref))
typedef CPpmd7_Context * CTX_PTR;
#define SUCCESSOR(p) Ppmd_GET_SUCCESSOR(p)
void Ppmd7_UpdateModel(CPpmd7 *p);
#define MASK(sym) ((unsigned char *)charMask)[sym]
// MY_FORCE_INLINE
// static
int Ppmd7z_DecodeSymbol(CPpmd7 *p)
{
size_t charMask[256 / sizeof(size_t)];
if (p->MinContext->NumStats != 1)
{
CPpmd_State *s = Ppmd7_GetStats(p, p->MinContext);
unsigned i;
UInt32 count, hiCnt;
UInt32 summFreq = p->MinContext->Union2.SummFreq;
count = RC_GetThreshold(summFreq);
hiCnt = count;
if ((Int32)(count -= s->Freq) < 0)
{
Byte sym;
RC_DecodeFinal(0, s->Freq);
p->FoundState = s;
sym = s->Symbol;
Ppmd7_Update1_0(p);
return sym;
}
p->PrevSuccess = 0;
i = (unsigned)p->MinContext->NumStats - 1;
do
{
if ((Int32)(count -= (++s)->Freq) < 0)
{
Byte sym;
RC_DecodeFinal((hiCnt - count) - s->Freq, s->Freq);
p->FoundState = s;
sym = s->Symbol;
Ppmd7_Update1(p);
return sym;
}
}
while (--i);
if (hiCnt >= summFreq)
return PPMD7_SYM_ERROR;
hiCnt -= count;
RC_Decode(hiCnt, summFreq - hiCnt);
p->HiBitsFlag = PPMD7_HiBitsFlag_3(p->FoundState->Symbol);
PPMD_SetAllBitsIn256Bytes(charMask);
// i = p->MinContext->NumStats - 1;
// do { MASK((--s)->Symbol) = 0; } while (--i);
{
CPpmd_State *s2 = Ppmd7_GetStats(p, p->MinContext);
MASK(s->Symbol) = 0;
do
{
unsigned sym0 = s2[0].Symbol;
unsigned sym1 = s2[1].Symbol;
s2 += 2;
MASK(sym0) = 0;
MASK(sym1) = 0;
}
while (s2 < s);
}
}
else
{
CPpmd_State *s = Ppmd7Context_OneState(p->MinContext);
UInt16 *prob = Ppmd7_GetBinSumm(p);
UInt32 pr = *prob;
UInt32 size0 = (R->Range >> 14) * pr;
pr = PPMD_UPDATE_PROB_1(pr);
if (R->Code < size0)
{
Byte sym;
*prob = (UInt16)(pr + (1 << PPMD_INT_BITS));
// RangeDec_DecodeBit0(size0);
R->Range = size0;
RC_NORM_1(R)
/* we can use single byte normalization here because of
(min(BinSumm[][]) = 95) > (1 << (14 - 8)) */
// sym = (p->FoundState = Ppmd7Context_OneState(p->MinContext))->Symbol;
// Ppmd7_UpdateBin(p);
{
unsigned freq = s->Freq;
CTX_PTR c = CTX(SUCCESSOR(s));
sym = s->Symbol;
p->FoundState = s;
p->PrevSuccess = 1;
p->RunLength++;
s->Freq = (Byte)(freq + (freq < 128));
// NextContext(p);
if (p->OrderFall == 0 && (const Byte *)c > p->Text)
p->MaxContext = p->MinContext = c;
else
Ppmd7_UpdateModel(p);
}
return sym;
}
*prob = (UInt16)pr;
p->InitEsc = p->ExpEscape[pr >> 10];
// RangeDec_DecodeBit1(size0);
R->Code -= size0;
R->Range -= size0;
RC_NORM_LOCAL(R)
PPMD_SetAllBitsIn256Bytes(charMask);
MASK(Ppmd7Context_OneState(p->MinContext)->Symbol) = 0;
p->PrevSuccess = 0;
}
for (;;)
{
CPpmd_State *s, *s2;
UInt32 freqSum, count, hiCnt;
CPpmd_See *see;
CPpmd7_Context *mc;
unsigned numMasked;
RC_NORM_REMOTE(R)
mc = p->MinContext;
numMasked = mc->NumStats;
do
{
p->OrderFall++;
if (!mc->Suffix)
return PPMD7_SYM_END;
mc = Ppmd7_GetContext(p, mc->Suffix);
}
while (mc->NumStats == numMasked);
s = Ppmd7_GetStats(p, mc);
{
unsigned num = mc->NumStats;
unsigned num2 = num / 2;
num &= 1;
hiCnt = (s->Freq & (unsigned)(MASK(s->Symbol))) & (0 - (UInt32)num);
s += num;
p->MinContext = mc;
do
{
unsigned sym0 = s[0].Symbol;
unsigned sym1 = s[1].Symbol;
s += 2;
hiCnt += (s[-2].Freq & (unsigned)(MASK(sym0)));
hiCnt += (s[-1].Freq & (unsigned)(MASK(sym1)));
}
while (--num2);
}
see = Ppmd7_MakeEscFreq(p, numMasked, &freqSum);
freqSum += hiCnt;
count = RC_GetThreshold(freqSum);
if (count < hiCnt)
{
Byte sym;
s = Ppmd7_GetStats(p, p->MinContext);
hiCnt = count;
// count -= s->Freq & (unsigned)(MASK(s->Symbol));
// if ((Int32)count >= 0)
{
for (;;)
{
count -= s->Freq & (unsigned)(MASK((s)->Symbol)); s++; if ((Int32)count < 0) break;
// count -= s->Freq & (unsigned)(MASK((s)->Symbol)); s++; if ((Int32)count < 0) break;
};
}
s--;
RC_DecodeFinal((hiCnt - count) - s->Freq, s->Freq);
// new (see->Summ) value can overflow over 16-bits in some rare cases
Ppmd_See_Update(see);
p->FoundState = s;
sym = s->Symbol;
Ppmd7_Update2(p);
return sym;
}
if (count >= freqSum)
return PPMD7_SYM_ERROR;
RC_Decode(hiCnt, freqSum - hiCnt);
// We increase (see->Summ) for sum of Freqs of all non_Masked symbols.
// new (see->Summ) value can overflow over 16-bits in some rare cases
see->Summ = (UInt16)(see->Summ + freqSum);
s = Ppmd7_GetStats(p, p->MinContext);
s2 = s + p->MinContext->NumStats;
do
{
MASK(s->Symbol) = 0;
s++;
}
while (s != s2);
}
}
/*
Byte *Ppmd7z_DecodeSymbols(CPpmd7 *p, Byte *buf, const Byte *lim)
{
int sym = 0;
if (buf != lim)
do
{
sym = Ppmd7z_DecodeSymbol(p);
if (sym < 0)
break;
*buf = (Byte)sym;
}
while (++buf < lim);
p->LastSymbol = sym;
return buf;
}
*/