/* Bcj2.c -- Converter for x86 code (BCJ2)

2008-10-04 : Igor Pavlov : Public domain */

#include "Precomp.h"

#include "Bcj2.h"

#ifdef _LZMA_PROB32

#define CProb UInt32

#else

#define CProb UInt16

#endif

#define IsJcc(b0, b1) ((b0) == 0x0F && ((b1) & 0xF0) == 0x80)

#define IsJ(b0, b1) ((b1 & 0xFE) == 0xE8 || IsJcc(b0, b1))

#define kNumTopBits 24

#define kTopValue ((UInt32)1 << kNumTopBits)

#define kNumBitModelTotalBits 11

#define kBitModelTotal (1 << kNumBitModelTotalBits)

#define kNumMoveBits 5

#define RC_READ_BYTE (*buffer++)

#define RC_TEST { if (buffer == bufferLim) return SZ_ERROR_DATA; }

#define RC_INIT2 code = 0; range = 0xFFFFFFFF; \

{ int i; for (i = 0; i < 5; i++) { RC_TEST; code = (code << 8) | RC_READ_BYTE; }}

#define NORMALIZE if (range < kTopValue) { RC_TEST; range <<= 8; code = (code << 8) | RC_READ_BYTE; }

#define IF_BIT_0(p) ttt = *(p); bound = (range >> kNumBitModelTotalBits) * ttt; if (code < bound)

#define UPDATE_0(p) range = bound; *(p) = (CProb)(ttt + ((kBitModelTotal - ttt) >> kNumMoveBits)); NORMALIZE;

#define UPDATE_1(p) range -= bound; code -= bound; *(p) = (CProb)(ttt - (ttt >> kNumMoveBits)); NORMALIZE;

int Bcj2_Decode(

Byte *outBuf, SizeT outSize)

{

CProb p[256 + 2];

SizeT inPos = 0, outPos = 0;

const Byte *buffer, *bufferLim;

UInt32 range, code;

Byte prevByte = 0;

unsigned int i;

for (i = 0; i < sizeof(p) / sizeof(p[0]); i++)

p[i] = kBitModelTotal >> 1;

buffer = buf3;

bufferLim = buffer + size3;

RC_INIT2

if (outSize == 0)

return SZ_OK;

for (;;)

{

Byte b;

CProb *prob;

UInt32 bound;

UInt32 ttt;

SizeT limit = size0 - inPos;

if (outSize - outPos < limit)

limit = outSize - outPos;

while (limit != 0)

{

Byte b = buf0[inPos];

outBuf[outPos++] = b;

if (IsJ(prevByte, b))

break;

inPos++;

prevByte = b;

limit--;

}

if (limit == 0 || outPos == outSize)

break;

b = buf0[inPos++];

if (b == 0xE8)

prob = p + prevByte;

else if (b == 0xE9)

prob = p + 256;

else

prob = p + 257;

IF_BIT_0(prob)

{

UPDATE_0(prob)

prevByte = b;

}

else

{

UInt32 dest;

const Byte *v;

UPDATE_1(prob)

if (b == 0xE8)

{

v = buf1;

if (size1 < 4)

return SZ_ERROR_DATA;

buf1 += 4;

size1 -= 4;

}

else

{

v = buf2;

if (size2 < 4)

return SZ_ERROR_DATA;

buf2 += 4;

size2 -= 4;

}

dest = (((UInt32)v[0] << 24) | ((UInt32)v[1] << 16) |

((UInt32)v[2] << 8) | ((UInt32)v[3])) - ((UInt32)outPos + 4);

outBuf[outPos++] = (Byte)dest;

if (outPos == outSize)

break;

outBuf[outPos++] = (Byte)(dest >> 8);

if (outPos == outSize)

break;

outBuf[outPos++] = (Byte)(dest >> 16);

if (outPos == outSize)

break;

outBuf[outPos++] = prevByte = (Byte)(dest >> 24);

}

}

return (outPos == outSize) ? SZ_OK : SZ_ERROR_DATA;

}