/src/lzma-fuzz/sdk/C/Ppmd7Dec.c
Line | Count | Source (jump to first uncovered line) |
1 | | /* Ppmd7Dec.c -- PPMdH Decoder |
2 | | 2018-07-04 : Igor Pavlov : Public domain |
3 | | This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */ |
4 | | |
5 | | #include "Precomp.h" |
6 | | |
7 | | #include "Ppmd7.h" |
8 | | |
9 | 13.5M | #define kTopValue (1 << 24) |
10 | | |
11 | | BoolInt Ppmd7z_RangeDec_Init(CPpmd7z_RangeDec *p) |
12 | 1.61k | { |
13 | 1.61k | unsigned i; |
14 | 1.61k | p->Code = 0; |
15 | 1.61k | p->Range = 0xFFFFFFFF; |
16 | 1.61k | if (IByteIn_Read(p->Stream) != 0) |
17 | 0 | return False; |
18 | 8.09k | for (i = 0; i < 4; i++) |
19 | 6.47k | p->Code = (p->Code << 8) | IByteIn_Read(p->Stream); |
20 | 1.61k | return (p->Code < 0xFFFFFFFF); |
21 | 1.61k | } |
22 | | |
23 | 15.1M | #define GET_Ppmd7z_RangeDec CPpmd7z_RangeDec *p = CONTAINER_FROM_VTBL(pp, CPpmd7z_RangeDec, vt); |
24 | | |
25 | | static UInt32 Range_GetThreshold(const IPpmd7_RangeDec *pp, UInt32 total) |
26 | 6.67M | { |
27 | 6.67M | GET_Ppmd7z_RangeDec |
28 | 6.67M | return p->Code / (p->Range /= total); |
29 | 6.67M | } |
30 | | |
31 | | static void Range_Normalize(CPpmd7z_RangeDec *p) |
32 | 8.50M | { |
33 | 8.50M | if (p->Range < kTopValue) |
34 | 5.00M | { |
35 | 5.00M | p->Code = (p->Code << 8) | IByteIn_Read(p->Stream); |
36 | 5.00M | p->Range <<= 8; |
37 | 5.00M | if (p->Range < kTopValue) |
38 | 667k | { |
39 | 667k | p->Code = (p->Code << 8) | IByteIn_Read(p->Stream); |
40 | 667k | p->Range <<= 8; |
41 | 667k | } |
42 | 5.00M | } |
43 | 8.50M | } |
44 | | |
45 | | static void Range_Decode(const IPpmd7_RangeDec *pp, UInt32 start, UInt32 size) |
46 | 6.67M | { |
47 | 6.67M | GET_Ppmd7z_RangeDec |
48 | 6.67M | p->Code -= start * p->Range; |
49 | 6.67M | p->Range *= size; |
50 | 6.67M | Range_Normalize(p); |
51 | 6.67M | } |
52 | | |
53 | | static UInt32 Range_DecodeBit(const IPpmd7_RangeDec *pp, UInt32 size0) |
54 | 1.83M | { |
55 | 1.83M | GET_Ppmd7z_RangeDec |
56 | 1.83M | UInt32 newBound = (p->Range >> 14) * size0; |
57 | 1.83M | UInt32 symbol; |
58 | 1.83M | if (p->Code < newBound) |
59 | 1.50M | { |
60 | 1.50M | symbol = 0; |
61 | 1.50M | p->Range = newBound; |
62 | 1.50M | } |
63 | 329k | else |
64 | 329k | { |
65 | 329k | symbol = 1; |
66 | 329k | p->Code -= newBound; |
67 | 329k | p->Range -= newBound; |
68 | 329k | } |
69 | 1.83M | Range_Normalize(p); |
70 | 1.83M | return symbol; |
71 | 1.83M | } |
72 | | |
73 | | void Ppmd7z_RangeDec_CreateVTable(CPpmd7z_RangeDec *p) |
74 | 1.61k | { |
75 | 1.61k | p->vt.GetThreshold = Range_GetThreshold; |
76 | 1.61k | p->vt.Decode = Range_Decode; |
77 | 1.61k | p->vt.DecodeBit = Range_DecodeBit; |
78 | 1.61k | } |
79 | | |
80 | | |
81 | 107M | #define MASK(sym) ((signed char *)charMask)[sym] |
82 | | |
83 | | int Ppmd7_DecodeSymbol(CPpmd7 *p, const IPpmd7_RangeDec *rc) |
84 | 7.95M | { |
85 | 7.95M | size_t charMask[256 / sizeof(size_t)]; |
86 | 7.95M | if (p->MinContext->NumStats != 1) |
87 | 6.12M | { |
88 | 6.12M | CPpmd_State *s = Ppmd7_GetStats(p, p->MinContext); |
89 | 6.12M | unsigned i; |
90 | 6.12M | UInt32 count, hiCnt; |
91 | 6.12M | if ((count = rc->GetThreshold(rc, p->MinContext->SummFreq)) < (hiCnt = s->Freq)) |
92 | 1.44M | { |
93 | 1.44M | Byte symbol; |
94 | 1.44M | rc->Decode(rc, 0, s->Freq); |
95 | 1.44M | p->FoundState = s; |
96 | 1.44M | symbol = s->Symbol; |
97 | 1.44M | Ppmd7_Update1_0(p); |
98 | 1.44M | return symbol; |
99 | 1.44M | } |
100 | 4.68M | p->PrevSuccess = 0; |
101 | 4.68M | i = p->MinContext->NumStats - 1; |
102 | 4.68M | do |
103 | 597M | { |
104 | 597M | if ((hiCnt += (++s)->Freq) > count) |
105 | 4.53M | { |
106 | 4.53M | Byte symbol; |
107 | 4.53M | rc->Decode(rc, hiCnt - s->Freq, s->Freq); |
108 | 4.53M | p->FoundState = s; |
109 | 4.53M | symbol = s->Symbol; |
110 | 4.53M | Ppmd7_Update1(p); |
111 | 4.53M | return symbol; |
112 | 4.53M | } |
113 | 597M | } |
114 | 592M | while (--i); |
115 | 152k | if (count >= p->MinContext->SummFreq) |
116 | 0 | return -2; |
117 | 152k | p->HiBitsFlag = p->HB2Flag[p->FoundState->Symbol]; |
118 | 152k | rc->Decode(rc, hiCnt, p->MinContext->SummFreq - hiCnt); |
119 | 152k | PPMD_SetAllBitsIn256Bytes(charMask); |
120 | 152k | MASK(s->Symbol) = 0; |
121 | 152k | i = p->MinContext->NumStats - 1; |
122 | 486k | do { MASK((--s)->Symbol) = 0; } while (--i); |
123 | 152k | } |
124 | 1.83M | else |
125 | 1.83M | { |
126 | 1.83M | UInt16 *prob = Ppmd7_GetBinSumm(p); |
127 | 1.83M | if (rc->DecodeBit(rc, *prob) == 0) |
128 | 1.50M | { |
129 | 1.50M | Byte symbol; |
130 | 1.50M | *prob = (UInt16)PPMD_UPDATE_PROB_0(*prob); |
131 | 1.50M | symbol = (p->FoundState = Ppmd7Context_OneState(p->MinContext))->Symbol; |
132 | 1.50M | Ppmd7_UpdateBin(p); |
133 | 1.50M | return symbol; |
134 | 1.50M | } |
135 | 329k | *prob = (UInt16)PPMD_UPDATE_PROB_1(*prob); |
136 | 329k | p->InitEsc = PPMD7_kExpEscape[*prob >> 10]; |
137 | 329k | PPMD_SetAllBitsIn256Bytes(charMask); |
138 | 329k | MASK(Ppmd7Context_OneState(p->MinContext)->Symbol) = 0; |
139 | 329k | p->PrevSuccess = 0; |
140 | 329k | } |
141 | 481k | for (;;) |
142 | 549k | { |
143 | 549k | CPpmd_State *ps[256], *s; |
144 | 549k | UInt32 freqSum, count, hiCnt; |
145 | 549k | CPpmd_See *see; |
146 | 549k | unsigned i, num, numMasked = p->MinContext->NumStats; |
147 | 549k | do |
148 | 769k | { |
149 | 769k | p->OrderFall++; |
150 | 769k | if (!p->MinContext->Suffix) |
151 | 0 | return -1; |
152 | 769k | p->MinContext = Ppmd7_GetContext(p, p->MinContext->Suffix); |
153 | 769k | } |
154 | 769k | while (p->MinContext->NumStats == numMasked); |
155 | 549k | hiCnt = 0; |
156 | 549k | s = Ppmd7_GetStats(p, p->MinContext); |
157 | 549k | i = 0; |
158 | 549k | num = p->MinContext->NumStats - numMasked; |
159 | 549k | do |
160 | 105M | { |
161 | 105M | int k = (int)(MASK(s->Symbol)); |
162 | 105M | hiCnt += (s->Freq & k); |
163 | 105M | ps[i] = s++; |
164 | 105M | i -= k; |
165 | 105M | } |
166 | 105M | while (i != num); |
167 | | |
168 | 549k | see = Ppmd7_MakeEscFreq(p, numMasked, &freqSum); |
169 | 549k | freqSum += hiCnt; |
170 | 549k | count = rc->GetThreshold(rc, freqSum); |
171 | | |
172 | 549k | if (count < hiCnt) |
173 | 481k | { |
174 | 481k | Byte symbol; |
175 | 481k | CPpmd_State **pps = ps; |
176 | 39.9M | for (hiCnt = 0; (hiCnt += (*pps)->Freq) <= count; pps++); |
177 | 481k | s = *pps; |
178 | 481k | rc->Decode(rc, hiCnt - s->Freq, s->Freq); |
179 | 481k | Ppmd_See_Update(see); |
180 | 481k | p->FoundState = s; |
181 | 481k | symbol = s->Symbol; |
182 | 481k | Ppmd7_Update2(p); |
183 | 481k | return symbol; |
184 | 481k | } |
185 | 68.3k | if (count >= freqSum) |
186 | 0 | return -2; |
187 | 68.3k | rc->Decode(rc, hiCnt, freqSum - hiCnt); |
188 | 68.3k | see->Summ = (UInt16)(see->Summ + freqSum); |
189 | 163k | do { MASK(ps[--i]->Symbol) = 0; } while (i != 0); |
190 | 68.3k | } |
191 | 481k | } |