mirror of
https://github.com/ZDoom/gzdoom.git
synced 2024-11-05 12:30:32 +00:00
132 lines
3.2 KiB
C
132 lines
3.2 KiB
C
/* 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;
|
|
}
|