/* Bra86.c -- Converter for x86 code (BCJ) | |
2013-11-12 : Igor Pavlov : Public domain */ | |
#include "Precomp.h" | |
#include "Bra.h" | |
#define Test86MSByte(b) ((((b) + 1) & 0xFE) == 0) | |
SizeT x86_Convert(Byte *data, SizeT size, UInt32 ip, UInt32 *state, int encoding) | |
{ | |
SizeT pos = 0; | |
UInt32 mask = *state & 7; | |
if (size < 5) | |
return 0; | |
size -= 4; | |
ip += 5; | |
for (;;) | |
{ | |
Byte *p = data + pos; | |
const Byte *limit = data + size; | |
for (; p < limit; p++) | |
if ((*p & 0xFE) == 0xE8) | |
break; | |
{ | |
SizeT d = (SizeT)(p - data - pos); | |
pos = (SizeT)(p - data); | |
if (p >= limit) | |
{ | |
*state = (d > 2 ? 0 : mask >> (unsigned)d); | |
return pos; | |
} | |
if (d > 2) | |
mask = 0; | |
else | |
{ | |
mask >>= (unsigned)d; | |
if (mask != 0 && (mask > 4 || mask == 3 || Test86MSByte(p[(mask >> 1) + 1]))) | |
{ | |
mask = (mask >> 1) | 4; | |
pos++; | |
continue; | |
} | |
} | |
} | |
if (Test86MSByte(p[4])) | |
{ | |
UInt32 v = ((UInt32)p[4] << 24) | ((UInt32)p[3] << 16) | ((UInt32)p[2] << 8) | ((UInt32)p[1]); | |
UInt32 cur = ip + (UInt32)pos; | |
pos += 5; | |
if (encoding) | |
v += cur; | |
else | |
v -= cur; | |
if (mask != 0) | |
{ | |
unsigned sh = (mask & 6) << 2; | |
if (Test86MSByte((Byte)(v >> sh))) | |
{ | |
v ^= (((UInt32)0x100 << sh) - 1); | |
if (encoding) | |
v += cur; | |
else | |
v -= cur; | |
} | |
mask = 0; | |
} | |
p[1] = (Byte)v; | |
p[2] = (Byte)(v >> 8); | |
p[3] = (Byte)(v >> 16); | |
p[4] = (Byte)(0 - ((v >> 24) & 1)); | |
} | |
else | |
{ | |
mask = (mask >> 1) | 4; | |
pos++; | |
} | |
} | |
} |