1/* Ppmd7Enc.c -- PPMdH Encoder
22010-03-12 : Igor Pavlov : Public domain
3This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */
4
5#include "Ppmd7.h"
6
7#define kTopValue (1 << 24)
8
9void Ppmd7z_RangeEnc_Init(CPpmd7z_RangeEnc *p)
10{
11  p->Low = 0;
12  p->Range = 0xFFFFFFFF;
13  p->Cache = 0;
14  p->CacheSize = 1;
15}
16
17static void RangeEnc_ShiftLow(CPpmd7z_RangeEnc *p)
18{
19  if ((UInt32)p->Low < (UInt32)0xFF000000 || (unsigned)(p->Low >> 32) != 0)
20  {
21    Byte temp = p->Cache;
22    do
23    {
24      p->Stream->Write(p->Stream, (Byte)(temp + (Byte)(p->Low >> 32)));
25      temp = 0xFF;
26    }
27    while(--p->CacheSize != 0);
28    p->Cache = (Byte)((UInt32)p->Low >> 24);
29  }
30  p->CacheSize++;
31  p->Low = (UInt32)p->Low << 8;
32}
33
34static void RangeEnc_Encode(CPpmd7z_RangeEnc *p, UInt32 start, UInt32 size, UInt32 total)
35{
36  p->Low += start * (p->Range /= total);
37  p->Range *= size;
38  while (p->Range < kTopValue)
39  {
40    p->Range <<= 8;
41    RangeEnc_ShiftLow(p);
42  }
43}
44
45static void RangeEnc_EncodeBit_0(CPpmd7z_RangeEnc *p, UInt32 size0)
46{
47  p->Range = (p->Range >> 14) * size0;
48  while (p->Range < kTopValue)
49  {
50    p->Range <<= 8;
51    RangeEnc_ShiftLow(p);
52  }
53}
54
55static void RangeEnc_EncodeBit_1(CPpmd7z_RangeEnc *p, UInt32 size0)
56{
57  UInt32 newBound = (p->Range >> 14) * size0;
58  p->Low += newBound;
59  p->Range -= newBound;
60  while (p->Range < kTopValue)
61  {
62    p->Range <<= 8;
63    RangeEnc_ShiftLow(p);
64  }
65}
66
67void Ppmd7z_RangeEnc_FlushData(CPpmd7z_RangeEnc *p)
68{
69  unsigned i;
70  for (i = 0; i < 5; i++)
71    RangeEnc_ShiftLow(p);
72}
73
74
75#define MASK(sym) ((signed char *)charMask)[sym]
76
77void Ppmd7_EncodeSymbol(CPpmd7 *p, CPpmd7z_RangeEnc *rc, int symbol)
78{
79  size_t charMask[256 / sizeof(size_t)];
80  if (p->MinContext->NumStats != 1)
81  {
82    CPpmd_State *s = Ppmd7_GetStats(p, p->MinContext);
83    UInt32 sum;
84    unsigned i;
85    if (s->Symbol == symbol)
86    {
87      RangeEnc_Encode(rc, 0, s->Freq, p->MinContext->SummFreq);
88      p->FoundState = s;
89      Ppmd7_Update1_0(p);
90      return;
91    }
92    p->PrevSuccess = 0;
93    sum = s->Freq;
94    i = p->MinContext->NumStats - 1;
95    do
96    {
97      if ((++s)->Symbol == symbol)
98      {
99        RangeEnc_Encode(rc, sum, s->Freq, p->MinContext->SummFreq);
100        p->FoundState = s;
101        Ppmd7_Update1(p);
102        return;
103      }
104      sum += s->Freq;
105    }
106    while (--i);
107
108    p->HiBitsFlag = p->HB2Flag[p->FoundState->Symbol];
109    PPMD_SetAllBitsIn256Bytes(charMask);
110    MASK(s->Symbol) = 0;
111    i = p->MinContext->NumStats - 1;
112    do { MASK((--s)->Symbol) = 0; } while (--i);
113    RangeEnc_Encode(rc, sum, p->MinContext->SummFreq - sum, p->MinContext->SummFreq);
114  }
115  else
116  {
117    UInt16 *prob = Ppmd7_GetBinSumm(p);
118    CPpmd_State *s = Ppmd7Context_OneState(p->MinContext);
119    if (s->Symbol == symbol)
120    {
121      RangeEnc_EncodeBit_0(rc, *prob);
122      *prob = (UInt16)PPMD_UPDATE_PROB_0(*prob);
123      p->FoundState = s;
124      Ppmd7_UpdateBin(p);
125      return;
126    }
127    else
128    {
129      RangeEnc_EncodeBit_1(rc, *prob);
130      *prob = (UInt16)PPMD_UPDATE_PROB_1(*prob);
131      p->InitEsc = PPMD7_kExpEscape[*prob >> 10];
132      PPMD_SetAllBitsIn256Bytes(charMask);
133      MASK(s->Symbol) = 0;
134      p->PrevSuccess = 0;
135    }
136  }
137  for (;;)
138  {
139    UInt32 escFreq;
140    CPpmd_See *see;
141    CPpmd_State *s;
142    UInt32 sum;
143    unsigned i, numMasked = p->MinContext->NumStats;
144    do
145    {
146      p->OrderFall++;
147      if (!p->MinContext->Suffix)
148        return; /* EndMarker (symbol = -1) */
149      p->MinContext = Ppmd7_GetContext(p, p->MinContext->Suffix);
150    }
151    while (p->MinContext->NumStats == numMasked);
152
153    see = Ppmd7_MakeEscFreq(p, numMasked, &escFreq);
154    s = Ppmd7_GetStats(p, p->MinContext);
155    sum = 0;
156    i = p->MinContext->NumStats;
157    do
158    {
159      int cur = s->Symbol;
160      if (cur == symbol)
161      {
162        UInt32 low = sum;
163        CPpmd_State *s1 = s;
164        do
165        {
166          sum += (s->Freq & (int)(MASK(s->Symbol)));
167          s++;
168        }
169        while (--i);
170        RangeEnc_Encode(rc, low, s1->Freq, sum + escFreq);
171        Ppmd_See_Update(see);
172        p->FoundState = s1;
173        Ppmd7_Update2(p);
174        return;
175      }
176      sum += (s->Freq & (int)(MASK(cur)));
177      MASK(cur) = 0;
178      s++;
179    }
180    while (--i);
181
182    RangeEnc_Encode(rc, sum, escFreq, sum + escFreq);
183    see->Summ = (UInt16)(see->Summ + sum + escFreq);
184  }
185}
186