| /* Bcj2.c -- Converter for x86 code (BCJ2) |
| 2008-10-04 : Igor Pavlov : Public domain */ |
| |
| #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( |
| const Byte *buf0, SizeT size0, |
| const Byte *buf1, SizeT size1, |
| const Byte *buf2, SizeT size2, |
| const Byte *buf3, SizeT size3, |
| 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; |
| } |