| repo sync | baa3858 | 2013-07-26 17:53:31 -0700 | [diff] [blame] | 1 | /* Bcj2.c -- Converter for x86 code (BCJ2)
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| 2 | 2008-10-04 : Igor Pavlov : Public domain */
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| 3 |
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| 4 | #include "Bcj2.h"
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| 5 |
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| 6 | #ifdef _LZMA_PROB32
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| 7 | #define CProb UInt32
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| 8 | #else
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| 9 | #define CProb UInt16
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| 10 | #endif
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| 11 |
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| 12 | #define IsJcc(b0, b1) ((b0) == 0x0F && ((b1) & 0xF0) == 0x80)
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| 13 | #define IsJ(b0, b1) ((b1 & 0xFE) == 0xE8 || IsJcc(b0, b1))
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| 14 |
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| 15 | #define kNumTopBits 24
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| 16 | #define kTopValue ((UInt32)1 << kNumTopBits)
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| 17 |
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| 18 | #define kNumBitModelTotalBits 11
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| 19 | #define kBitModelTotal (1 << kNumBitModelTotalBits)
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| 20 | #define kNumMoveBits 5
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| 21 |
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| 22 | #define RC_READ_BYTE (*buffer++)
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| 23 | #define RC_TEST { if (buffer == bufferLim) return SZ_ERROR_DATA; }
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| 24 | #define RC_INIT2 code = 0; range = 0xFFFFFFFF; \
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| 25 | { int i; for (i = 0; i < 5; i++) { RC_TEST; code = (code << 8) | RC_READ_BYTE; }}
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| 26 |
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| 27 | #define NORMALIZE if (range < kTopValue) { RC_TEST; range <<= 8; code = (code << 8) | RC_READ_BYTE; }
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| 28 |
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| 29 | #define IF_BIT_0(p) ttt = *(p); bound = (range >> kNumBitModelTotalBits) * ttt; if (code < bound)
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| 30 | #define UPDATE_0(p) range = bound; *(p) = (CProb)(ttt + ((kBitModelTotal - ttt) >> kNumMoveBits)); NORMALIZE;
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| 31 | #define UPDATE_1(p) range -= bound; code -= bound; *(p) = (CProb)(ttt - (ttt >> kNumMoveBits)); NORMALIZE;
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| 32 |
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| 33 | int Bcj2_Decode(
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| 34 | const Byte *buf0, SizeT size0,
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| 35 | const Byte *buf1, SizeT size1,
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| 36 | const Byte *buf2, SizeT size2,
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| 37 | const Byte *buf3, SizeT size3,
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| 38 | Byte *outBuf, SizeT outSize)
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| 39 | {
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| 40 | CProb p[256 + 2];
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| 41 | SizeT inPos = 0, outPos = 0;
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| 42 |
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| 43 | const Byte *buffer, *bufferLim;
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| 44 | UInt32 range, code;
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| 45 | Byte prevByte = 0;
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| 46 |
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| 47 | unsigned int i;
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| 48 | for (i = 0; i < sizeof(p) / sizeof(p[0]); i++)
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| 49 | p[i] = kBitModelTotal >> 1;
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| 50 |
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| 51 | buffer = buf3;
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| 52 | bufferLim = buffer + size3;
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| 53 | RC_INIT2
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| 54 |
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| 55 | if (outSize == 0)
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| 56 | return SZ_OK;
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| 57 |
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| 58 | for (;;)
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| 59 | {
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| 60 | Byte b;
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| 61 | CProb *prob;
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| 62 | UInt32 bound;
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| 63 | UInt32 ttt;
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| 64 |
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| 65 | SizeT limit = size0 - inPos;
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| 66 | if (outSize - outPos < limit)
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| 67 | limit = outSize - outPos;
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| 68 | while (limit != 0)
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| 69 | {
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| 70 | Byte b = buf0[inPos];
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| 71 | outBuf[outPos++] = b;
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| 72 | if (IsJ(prevByte, b))
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| 73 | break;
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| 74 | inPos++;
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| 75 | prevByte = b;
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| 76 | limit--;
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| 77 | }
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| 78 |
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| 79 | if (limit == 0 || outPos == outSize)
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| 80 | break;
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| 81 |
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| 82 | b = buf0[inPos++];
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| 83 |
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| 84 | if (b == 0xE8)
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| 85 | prob = p + prevByte;
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| 86 | else if (b == 0xE9)
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| 87 | prob = p + 256;
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| 88 | else
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| 89 | prob = p + 257;
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| 90 |
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| 91 | IF_BIT_0(prob)
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| 92 | {
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| 93 | UPDATE_0(prob)
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| 94 | prevByte = b;
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| 95 | }
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| 96 | else
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| 97 | {
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| 98 | UInt32 dest;
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| 99 | const Byte *v;
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| 100 | UPDATE_1(prob)
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| 101 | if (b == 0xE8)
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| 102 | {
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| 103 | v = buf1;
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| 104 | if (size1 < 4)
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| 105 | return SZ_ERROR_DATA;
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| 106 | buf1 += 4;
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| 107 | size1 -= 4;
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| 108 | }
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| 109 | else
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| 110 | {
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| 111 | v = buf2;
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| 112 | if (size2 < 4)
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| 113 | return SZ_ERROR_DATA;
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| 114 | buf2 += 4;
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| 115 | size2 -= 4;
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| 116 | }
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| 117 | dest = (((UInt32)v[0] << 24) | ((UInt32)v[1] << 16) |
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| 118 | ((UInt32)v[2] << 8) | ((UInt32)v[3])) - ((UInt32)outPos + 4);
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| 119 | outBuf[outPos++] = (Byte)dest;
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| 120 | if (outPos == outSize)
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| 121 | break;
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| 122 | outBuf[outPos++] = (Byte)(dest >> 8);
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| 123 | if (outPos == outSize)
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| 124 | break;
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| 125 | outBuf[outPos++] = (Byte)(dest >> 16);
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| 126 | if (outPos == outSize)
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| 127 | break;
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| 128 | outBuf[outPos++] = prevByte = (Byte)(dest >> 24);
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| 129 | }
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| 130 | }
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| 131 | return (outPos == outSize) ? SZ_OK : SZ_ERROR_DATA;
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| 132 | }
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