1// BranchX86_2.c
2
3#include "BranchX86_2.h"
4
5#include "../../Alloc.h"
6
7#ifdef _LZMA_PROB32
8#define CProb UInt32
9#else
10#define CProb UInt16
11#endif
12
13#define IsJcc(b0, b1) ((b0) == 0x0F && ((b1) & 0xF0) == 0x80)
14#define IsJ(b0, b1) ((b1 & 0xFE) == 0xE8 || IsJcc(b0, b1))
15
16#define kNumTopBits 24
17#define kTopValue ((UInt32)1 << kNumTopBits)
18
19#define kNumBitModelTotalBits 11
20#define kBitModelTotal (1 << kNumBitModelTotalBits)
21#define kNumMoveBits 5
22
23#define RC_READ_BYTE (*Buffer++)
24
25#define RC_INIT2 Code = 0; Range = 0xFFFFFFFF; \
26  { int i; for(i = 0; i < 5; i++) { RC_TEST; Code = (Code << 8) | RC_READ_BYTE; }}
27
28#define RC_TEST { if (Buffer == BufferLim) return BCJ2_RESULT_DATA_ERROR; }
29
30#define RC_INIT(buffer, bufferSize) Buffer = buffer; BufferLim = buffer + bufferSize; RC_INIT2
31
32#define RC_NORMALIZE if (Range < kTopValue) { RC_TEST; Range <<= 8; Code = (Code << 8) | RC_READ_BYTE; }
33
34#define IfBit0(p) RC_NORMALIZE; bound = (Range >> kNumBitModelTotalBits) * *(p); if (Code < bound)
35#define UpdateBit0(p) Range = bound; *(p) += (kBitModelTotal - *(p)) >> kNumMoveBits;
36#define UpdateBit1(p) Range -= bound; Code -= bound; *(p) -= (*(p)) >> kNumMoveBits;
37// #define UpdateBit0(p) Range = bound; *(p) = (CProb)(*(p) + ((kBitModelTotal - *(p)) >> kNumMoveBits));
38// #define UpdateBit1(p) Range -= bound; Code -= bound; *(p) = (CProb)(*(p) - (*(p) >> kNumMoveBits));
39
40int x86_2_Decode(
41    const Byte *buf0, SizeT size0,
42    const Byte *buf1, SizeT size1,
43    const Byte *buf2, SizeT size2,
44    const Byte *buf3, SizeT size3,
45    Byte *outBuf, SizeT outSize)
46{
47  CProb p[256 + 2];
48  SizeT inPos = 0, outPos = 0;
49
50  const Byte *Buffer, *BufferLim;
51  UInt32 Range, Code;
52  Byte prevByte = 0;
53
54  unsigned int i;
55  for (i = 0; i < sizeof(p) / sizeof(p[0]); i++)
56    p[i] = kBitModelTotal >> 1;
57  RC_INIT(buf3, size3);
58
59  if (outSize == 0)
60    return BCJ2_RESULT_OK;
61
62  for (;;)
63  {
64    Byte b;
65    CProb *prob;
66    UInt32 bound;
67
68    SizeT limit = size0 - inPos;
69    if (outSize - outPos < limit)
70      limit = outSize - outPos;
71    while (limit != 0)
72    {
73      Byte b = buf0[inPos];
74      outBuf[outPos++] = b;
75      if (IsJ(prevByte, b))
76        break;
77      inPos++;
78      prevByte = b;
79      limit--;
80    }
81
82    if (limit == 0 || outPos == outSize)
83      break;
84
85    b = buf0[inPos++];
86
87    if (b == 0xE8)
88      prob = p + prevByte;
89    else if (b == 0xE9)
90      prob = p + 256;
91    else
92      prob = p + 257;
93
94    IfBit0(prob)
95    {
96      UpdateBit0(prob)
97      prevByte = b;
98    }
99    else
100    {
101      UInt32 dest;
102      const Byte *v;
103      UpdateBit1(prob)
104      if (b == 0xE8)
105      {
106        v = buf1;
107        if (size1 < 4)
108          return BCJ2_RESULT_DATA_ERROR;
109        buf1 += 4;
110        size1 -= 4;
111      }
112      else
113      {
114        v = buf2;
115        if (size2 < 4)
116          return BCJ2_RESULT_DATA_ERROR;
117        buf2 += 4;
118        size2 -= 4;
119      }
120      dest = (((UInt32)v[0] << 24) | ((UInt32)v[1] << 16) |
121          ((UInt32)v[2] << 8) | ((UInt32)v[3])) - ((UInt32)outPos + 4);
122      outBuf[outPos++] = (Byte)dest;
123      if (outPos == outSize)
124        break;
125      outBuf[outPos++] = (Byte)(dest >> 8);
126      if (outPos == outSize)
127        break;
128      outBuf[outPos++] = (Byte)(dest >> 16);
129      if (outPos == outSize)
130        break;
131      outBuf[outPos++] = prevByte = (Byte)(dest >> 24);
132    }
133  }
134  return (outPos == outSize) ? BCJ2_RESULT_OK : BCJ2_RESULT_DATA_ERROR;
135}
136