| /* 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++; |
| } |
| } |
| } |