diff src/win32/7zip/7z/C/Bra86.c @ 1:f9f4f1b99eed

importing src directory
author Robert McIntyre <rlm@mit.edu>
date Sat, 03 Mar 2012 10:31:27 -0600
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     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/win32/7zip/7z/C/Bra86.c	Sat Mar 03 10:31:27 2012 -0600
     1.3 @@ -0,0 +1,85 @@
     1.4 +/* Bra86.c -- Converter for x86 code (BCJ)
     1.5 +2008-10-04 : Igor Pavlov : Public domain */
     1.6 +
     1.7 +#include "Bra.h"
     1.8 +
     1.9 +#define Test86MSByte(b) ((b) == 0 || (b) == 0xFF)
    1.10 +
    1.11 +const Byte kMaskToAllowedStatus[8] = {1, 1, 1, 0, 1, 0, 0, 0};
    1.12 +const Byte kMaskToBitNumber[8] = {0, 1, 2, 2, 3, 3, 3, 3};
    1.13 +
    1.14 +SizeT x86_Convert(Byte *data, SizeT size, UInt32 ip, UInt32 *state, int encoding)
    1.15 +{
    1.16 +  SizeT bufferPos = 0, prevPosT;
    1.17 +  UInt32 prevMask = *state & 0x7;
    1.18 +  if (size < 5)
    1.19 +    return 0;
    1.20 +  ip += 5;
    1.21 +  prevPosT = (SizeT)0 - 1;
    1.22 +
    1.23 +  for (;;)
    1.24 +  {
    1.25 +    Byte *p = data + bufferPos;
    1.26 +    Byte *limit = data + size - 4;
    1.27 +    for (; p < limit; p++)
    1.28 +      if ((*p & 0xFE) == 0xE8)
    1.29 +        break;
    1.30 +    bufferPos = (SizeT)(p - data);
    1.31 +    if (p >= limit)
    1.32 +      break;
    1.33 +    prevPosT = bufferPos - prevPosT;
    1.34 +    if (prevPosT > 3)
    1.35 +      prevMask = 0;
    1.36 +    else
    1.37 +    {
    1.38 +      prevMask = (prevMask << ((int)prevPosT - 1)) & 0x7;
    1.39 +      if (prevMask != 0)
    1.40 +      {
    1.41 +        Byte b = p[4 - kMaskToBitNumber[prevMask]];
    1.42 +        if (!kMaskToAllowedStatus[prevMask] || Test86MSByte(b))
    1.43 +        {
    1.44 +          prevPosT = bufferPos;
    1.45 +          prevMask = ((prevMask << 1) & 0x7) | 1;
    1.46 +          bufferPos++;
    1.47 +          continue;
    1.48 +        }
    1.49 +      }
    1.50 +    }
    1.51 +    prevPosT = bufferPos;
    1.52 +
    1.53 +    if (Test86MSByte(p[4]))
    1.54 +    {
    1.55 +      UInt32 src = ((UInt32)p[4] << 24) | ((UInt32)p[3] << 16) | ((UInt32)p[2] << 8) | ((UInt32)p[1]);
    1.56 +      UInt32 dest;
    1.57 +      for (;;)
    1.58 +      {
    1.59 +        Byte b;
    1.60 +        int index;
    1.61 +        if (encoding)
    1.62 +          dest = (ip + (UInt32)bufferPos) + src;
    1.63 +        else
    1.64 +          dest = src - (ip + (UInt32)bufferPos);
    1.65 +        if (prevMask == 0)
    1.66 +          break;
    1.67 +        index = kMaskToBitNumber[prevMask] * 8;
    1.68 +        b = (Byte)((dest >> (24 - index)) & 0xFF);
    1.69 +        if (!Test86MSByte(b))
    1.70 +          break;
    1.71 +        src = dest ^ ((1 << (32 - index)) - 1);
    1.72 +      }
    1.73 +      p[4] = (Byte)((~(((dest >> 24) & 1) - 1)) & 0xFF);
    1.74 +      p[3] = (Byte)((dest >> 16) & 0xFF);
    1.75 +      p[2] = (Byte)((dest >> 8) & 0xFF);
    1.76 +      p[1] = (Byte)(dest & 0xFF);
    1.77 +      bufferPos += 5;
    1.78 +    }
    1.79 +    else
    1.80 +    {
    1.81 +      prevMask = ((prevMask << 1) & 0x7) | 1;
    1.82 +      bufferPos++;
    1.83 +    }
    1.84 +  }
    1.85 +  prevPosT = bufferPos - prevPosT;
    1.86 +  *state = ((prevPosT > 3) ? 0 : ((prevMask << ((int)prevPosT - 1)) & 0x7));
    1.87 +  return bufferPos;
    1.88 +}