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qzdoom/lzma/C/Bcj2.c

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/* 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;
}