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| 1 /* Bcj2.c -- Converter for x86 code (BCJ2) | |
| 2 2008-10-04 : Igor Pavlov : Public domain */ | |
| 3 | |
| 4 #include "Bcj2.h" | |
| 5 | |
| 6 #ifdef _LZMA_PROB32 | |
| 7 #define CProb UInt32 | |
| 8 #else | |
| 9 #define CProb UInt16 | |
| 10 #endif | |
| 11 | |
| 12 #define IsJcc(b0, b1) ((b0) == 0x0F && ((b1) & 0xF0) == 0x80) | |
| 13 #define IsJ(b0, b1) ((b1 & 0xFE) == 0xE8 || IsJcc(b0, b1)) | |
| 14 | |
| 15 #define kNumTopBits 24 | |
| 16 #define kTopValue ((UInt32)1 << kNumTopBits) | |
| 17 | |
| 18 #define kNumBitModelTotalBits 11 | |
| 19 #define kBitModelTotal (1 << kNumBitModelTotalBits) | |
| 20 #define kNumMoveBits 5 | |
| 21 | |
| 22 #define RC_READ_BYTE (*buffer++) | |
| 23 #define RC_TEST { if (buffer == bufferLim) return SZ_ERROR_DATA; } | |
| 24 #define RC_INIT2 code = 0; range = 0xFFFFFFFF; \ | |
| 25 { int i; for (i = 0; i < 5; i++) { RC_TEST; code = (code << 8) | RC_READ_BYTE;
}} | |
| 26 | |
| 27 #define NORMALIZE if (range < kTopValue) { RC_TEST; range <<= 8; code = (code <<
8) | RC_READ_BYTE; } | |
| 28 | |
| 29 #define IF_BIT_0(p) ttt = *(p); bound = (range >> kNumBitModelTotalBits) * ttt;
if (code < bound) | |
| 30 #define UPDATE_0(p) range = bound; *(p) = (CProb)(ttt + ((kBitModelTotal - ttt)
>> kNumMoveBits)); NORMALIZE; | |
| 31 #define UPDATE_1(p) range -= bound; code -= bound; *(p) = (CProb)(ttt - (ttt >>
kNumMoveBits)); NORMALIZE; | |
| 32 | |
| 33 int Bcj2_Decode( | |
| 34 const Byte *buf0, SizeT size0, | |
| 35 const Byte *buf1, SizeT size1, | |
| 36 const Byte *buf2, SizeT size2, | |
| 37 const Byte *buf3, SizeT size3, | |
| 38 Byte *outBuf, SizeT outSize) | |
| 39 { | |
| 40 CProb p[256 + 2]; | |
| 41 SizeT inPos = 0, outPos = 0; | |
| 42 | |
| 43 const Byte *buffer, *bufferLim; | |
| 44 UInt32 range, code; | |
| 45 Byte prevByte = 0; | |
| 46 | |
| 47 unsigned int i; | |
| 48 for (i = 0; i < sizeof(p) / sizeof(p[0]); i++) | |
| 49 p[i] = kBitModelTotal >> 1; | |
| 50 | |
| 51 buffer = buf3; | |
| 52 bufferLim = buffer + size3; | |
| 53 RC_INIT2 | |
| 54 | |
| 55 if (outSize == 0) | |
| 56 return SZ_OK; | |
| 57 | |
| 58 for (;;) | |
| 59 { | |
| 60 Byte b; | |
| 61 CProb *prob; | |
| 62 UInt32 bound; | |
| 63 UInt32 ttt; | |
| 64 | |
| 65 SizeT limit = size0 - inPos; | |
| 66 if (outSize - outPos < limit) | |
| 67 limit = outSize - outPos; | |
| 68 while (limit != 0) | |
| 69 { | |
| 70 Byte b = buf0[inPos]; | |
| 71 outBuf[outPos++] = b; | |
| 72 if (IsJ(prevByte, b)) | |
| 73 break; | |
| 74 inPos++; | |
| 75 prevByte = b; | |
| 76 limit--; | |
| 77 } | |
| 78 | |
| 79 if (limit == 0 || outPos == outSize) | |
| 80 break; | |
| 81 | |
| 82 b = buf0[inPos++]; | |
| 83 | |
| 84 if (b == 0xE8) | |
| 85 prob = p + prevByte; | |
| 86 else if (b == 0xE9) | |
| 87 prob = p + 256; | |
| 88 else | |
| 89 prob = p + 257; | |
| 90 | |
| 91 IF_BIT_0(prob) | |
| 92 { | |
| 93 UPDATE_0(prob) | |
| 94 prevByte = b; | |
| 95 } | |
| 96 else | |
| 97 { | |
| 98 UInt32 dest; | |
| 99 const Byte *v; | |
| 100 UPDATE_1(prob) | |
| 101 if (b == 0xE8) | |
| 102 { | |
| 103 v = buf1; | |
| 104 if (size1 < 4) | |
| 105 return SZ_ERROR_DATA; | |
| 106 buf1 += 4; | |
| 107 size1 -= 4; | |
| 108 } | |
| 109 else | |
| 110 { | |
| 111 v = buf2; | |
| 112 if (size2 < 4) | |
| 113 return SZ_ERROR_DATA; | |
| 114 buf2 += 4; | |
| 115 size2 -= 4; | |
| 116 } | |
| 117 dest = (((UInt32)v[0] << 24) | ((UInt32)v[1] << 16) | | |
| 118 ((UInt32)v[2] << 8) | ((UInt32)v[3])) - ((UInt32)outPos + 4); | |
| 119 outBuf[outPos++] = (Byte)dest; | |
| 120 if (outPos == outSize) | |
| 121 break; | |
| 122 outBuf[outPos++] = (Byte)(dest >> 8); | |
| 123 if (outPos == outSize) | |
| 124 break; | |
| 125 outBuf[outPos++] = (Byte)(dest >> 16); | |
| 126 if (outPos == outSize) | |
| 127 break; | |
| 128 outBuf[outPos++] = prevByte = (Byte)(dest >> 24); | |
| 129 } | |
| 130 } | |
| 131 return (outPos == outSize) ? SZ_OK : SZ_ERROR_DATA; | |
| 132 } | |
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Chromium Code Reviews
Issue 624713003:
Keep only base/extractor.[cc|h]. (Closed)
Base URL: https://chromium.googlesource.com/external/omaha.git@master