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1 cycrow 1 
/* Bcj2.c -- Converter for x86 code (BCJ2)
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2008-10-04 : Igor Pavlov : Public domain */
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#include "Bcj2.h"
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#ifdef _LZMA_PROB32
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#define CProb UInt32
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#else
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#define CProb UInt16
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#endif
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#define IsJcc(b0, b1) ((b0) == 0x0F && ((b1) & 0xF0) == 0x80)
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#define IsJ(b0, b1) ((b1 & 0xFE) == 0xE8 || IsJcc(b0, b1))
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#define kNumTopBits 24
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#define kTopValue ((UInt32)1 << kNumTopBits)
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#define kNumBitModelTotalBits 11
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#define kBitModelTotal (1 << kNumBitModelTotalBits)
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#define kNumMoveBits 5
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#define RC_READ_BYTE (*buffer++)
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#define RC_TEST { if (buffer == bufferLim) return SZ_ERROR_DATA; }
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#define RC_INIT2 code = 0; range = 0xFFFFFFFF; \
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  { int i; for (i = 0; i < 5; i++) { RC_TEST; code = (code << 8) | RC_READ_BYTE; }}
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#define NORMALIZE if (range < kTopValue) { RC_TEST; range <<= 8; code = (code << 8) | RC_READ_BYTE; }
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#define IF_BIT_0(p) ttt = *(p); bound = (range >> kNumBitModelTotalBits) * ttt; if (code < bound)
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#define UPDATE_0(p) range = bound; *(p) = (CProb)(ttt + ((kBitModelTotal - ttt) >> kNumMoveBits)); NORMALIZE;
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#define UPDATE_1(p) range -= bound; code -= bound; *(p) = (CProb)(ttt - (ttt >> kNumMoveBits)); NORMALIZE;
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int Bcj2_Decode(
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    const Byte *buf0, SizeT size0,
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    const Byte *buf1, SizeT size1,
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    const Byte *buf2, SizeT size2,
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    const Byte *buf3, SizeT size3,
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    Byte *outBuf, SizeT outSize)
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{
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  CProb p[256 + 2];
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  SizeT inPos = 0, outPos = 0;
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  const Byte *buffer, *bufferLim;
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  UInt32 range, code;
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  Byte prevByte = 0;
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  unsigned int i;
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  for (i = 0; i < sizeof(p) / sizeof(p[0]); i++)
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    p[i] = kBitModelTotal >> 1;
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  buffer = buf3;
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  bufferLim = buffer + size3;
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  RC_INIT2
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  if (outSize == 0)
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    return SZ_OK;
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  for (;;)
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  {
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    Byte b;
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    CProb *prob;
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    UInt32 bound;
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    UInt32 ttt;
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    SizeT limit = size0 - inPos;
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    if (outSize - outPos < limit)
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      limit = outSize - outPos;
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    while (limit != 0)
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    {
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      Byte b = buf0[inPos];
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      outBuf[outPos++] = b;
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      if (IsJ(prevByte, b))
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        break;
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      inPos++;
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      prevByte = b;
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      limit--;
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    }
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    if (limit == 0 || outPos == outSize)
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      break;
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    b = buf0[inPos++];
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    if (b == 0xE8)
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      prob = p + prevByte;
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    else if (b == 0xE9)
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      prob = p + 256;
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    else
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      prob = p + 257;
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    IF_BIT_0(prob)
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    {
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      UPDATE_0(prob)
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      prevByte = b;
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    }
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    else
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    {
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      UInt32 dest;
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      const Byte *v;
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      UPDATE_1(prob)
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      if (b == 0xE8)
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      {
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        v = buf1;
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        if (size1 < 4)
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          return SZ_ERROR_DATA;
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        buf1 += 4;
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        size1 -= 4;
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      }
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      else
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      {
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        v = buf2;
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        if (size2 < 4)
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          return SZ_ERROR_DATA;
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        buf2 += 4;
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        size2 -= 4;
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      }
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      dest = (((UInt32)v[0] << 24) | ((UInt32)v[1] << 16) |
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          ((UInt32)v[2] << 8) | ((UInt32)v[3])) - ((UInt32)outPos + 4);
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      outBuf[outPos++] = (Byte)dest;
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      if (outPos == outSize)
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        break;
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      outBuf[outPos++] = (Byte)(dest >> 8);
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      if (outPos == outSize)
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        break;
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      outBuf[outPos++] = (Byte)(dest >> 16);
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      if (outPos == outSize)
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        break;
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      outBuf[outPos++] = prevByte = (Byte)(dest >> 24);
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    }
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  }
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  return (outPos == outSize) ? SZ_OK : SZ_ERROR_DATA;
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}