in MdeModulePkg/Library/LzmaCustomDecompressLib/Sdk/C/LzmaDec.c [220:587]
int MY_FAST_CALL LZMA_DECODE_REAL(CLzmaDec *p, SizeT limit, const Byte *bufLimit)
{
CLzmaProb *probs = GET_PROBS;
unsigned state = (unsigned)p->state;
UInt32 rep0 = p->reps[0], rep1 = p->reps[1], rep2 = p->reps[2], rep3 = p->reps[3];
unsigned pbMask = ((unsigned)1 << (p->prop.pb)) - 1;
unsigned lc = p->prop.lc;
unsigned lpMask = ((unsigned)0x100 << p->prop.lp) - ((unsigned)0x100 >> lc);
Byte *dic = p->dic;
SizeT dicBufSize = p->dicBufSize;
SizeT dicPos = p->dicPos;
UInt32 processedPos = p->processedPos;
UInt32 checkDicSize = p->checkDicSize;
unsigned len = 0;
const Byte *buf = p->buf;
UInt32 range = p->range;
UInt32 code = p->code;
do
{
CLzmaProb *prob;
UInt32 bound;
unsigned ttt;
unsigned posState = CALC_POS_STATE(processedPos, pbMask);
prob = probs + IsMatch + COMBINED_PS_STATE;
IF_BIT_0(prob)
{
unsigned symbol;
UPDATE_0(prob);
prob = probs + Literal;
if (processedPos != 0 || checkDicSize != 0)
prob += (UInt32)3 * ((((processedPos << 8) + dic[(dicPos == 0 ? dicBufSize : dicPos) - 1]) & lpMask) << lc);
processedPos++;
if (state < kNumLitStates)
{
state -= (state < 4) ? state : 3;
symbol = 1;
#ifdef _LZMA_SIZE_OPT
do { NORMAL_LITER_DEC } while (symbol < 0x100);
#else
NORMAL_LITER_DEC
NORMAL_LITER_DEC
NORMAL_LITER_DEC
NORMAL_LITER_DEC
NORMAL_LITER_DEC
NORMAL_LITER_DEC
NORMAL_LITER_DEC
NORMAL_LITER_DEC
#endif
}
else
{
unsigned matchByte = dic[dicPos - rep0 + (dicPos < rep0 ? dicBufSize : 0)];
unsigned offs = 0x100;
state -= (state < 10) ? 3 : 6;
symbol = 1;
#ifdef _LZMA_SIZE_OPT
do
{
unsigned bit;
CLzmaProb *probLit;
MATCHED_LITER_DEC
}
while (symbol < 0x100);
#else
{
unsigned bit;
CLzmaProb *probLit;
MATCHED_LITER_DEC
MATCHED_LITER_DEC
MATCHED_LITER_DEC
MATCHED_LITER_DEC
MATCHED_LITER_DEC
MATCHED_LITER_DEC
MATCHED_LITER_DEC
MATCHED_LITER_DEC
}
#endif
}
dic[dicPos++] = (Byte)symbol;
continue;
}
{
UPDATE_1(prob);
prob = probs + IsRep + state;
IF_BIT_0(prob)
{
UPDATE_0(prob);
state += kNumStates;
prob = probs + LenCoder;
}
else
{
UPDATE_1(prob);
/*
// that case was checked before with kBadRepCode
if (checkDicSize == 0 && processedPos == 0)
return SZ_ERROR_DATA;
*/
prob = probs + IsRepG0 + state;
IF_BIT_0(prob)
{
UPDATE_0(prob);
prob = probs + IsRep0Long + COMBINED_PS_STATE;
IF_BIT_0(prob)
{
UPDATE_0(prob);
dic[dicPos] = dic[dicPos - rep0 + (dicPos < rep0 ? dicBufSize : 0)];
dicPos++;
processedPos++;
state = state < kNumLitStates ? 9 : 11;
continue;
}
UPDATE_1(prob);
}
else
{
UInt32 distance;
UPDATE_1(prob);
prob = probs + IsRepG1 + state;
IF_BIT_0(prob)
{
UPDATE_0(prob);
distance = rep1;
}
else
{
UPDATE_1(prob);
prob = probs + IsRepG2 + state;
IF_BIT_0(prob)
{
UPDATE_0(prob);
distance = rep2;
}
else
{
UPDATE_1(prob);
distance = rep3;
rep3 = rep2;
}
rep2 = rep1;
}
rep1 = rep0;
rep0 = distance;
}
state = state < kNumLitStates ? 8 : 11;
prob = probs + RepLenCoder;
}
#ifdef _LZMA_SIZE_OPT
{
unsigned lim, offset;
CLzmaProb *probLen = prob + LenChoice;
IF_BIT_0(probLen)
{
UPDATE_0(probLen);
probLen = prob + LenLow + GET_LEN_STATE;
offset = 0;
lim = (1 << kLenNumLowBits);
}
else
{
UPDATE_1(probLen);
probLen = prob + LenChoice2;
IF_BIT_0(probLen)
{
UPDATE_0(probLen);
probLen = prob + LenLow + GET_LEN_STATE + (1 << kLenNumLowBits);
offset = kLenNumLowSymbols;
lim = (1 << kLenNumLowBits);
}
else
{
UPDATE_1(probLen);
probLen = prob + LenHigh;
offset = kLenNumLowSymbols * 2;
lim = (1 << kLenNumHighBits);
}
}
TREE_DECODE(probLen, lim, len);
len += offset;
}
#else
{
CLzmaProb *probLen = prob + LenChoice;
IF_BIT_0(probLen)
{
UPDATE_0(probLen);
probLen = prob + LenLow + GET_LEN_STATE;
len = 1;
TREE_GET_BIT(probLen, len);
TREE_GET_BIT(probLen, len);
TREE_GET_BIT(probLen, len);
len -= 8;
}
else
{
UPDATE_1(probLen);
probLen = prob + LenChoice2;
IF_BIT_0(probLen)
{
UPDATE_0(probLen);
probLen = prob + LenLow + GET_LEN_STATE + (1 << kLenNumLowBits);
len = 1;
TREE_GET_BIT(probLen, len);
TREE_GET_BIT(probLen, len);
TREE_GET_BIT(probLen, len);
}
else
{
UPDATE_1(probLen);
probLen = prob + LenHigh;
TREE_DECODE(probLen, (1 << kLenNumHighBits), len);
len += kLenNumLowSymbols * 2;
}
}
}
#endif
if (state >= kNumStates)
{
UInt32 distance;
prob = probs + PosSlot +
((len < kNumLenToPosStates ? len : kNumLenToPosStates - 1) << kNumPosSlotBits);
TREE_6_DECODE(prob, distance);
if (distance >= kStartPosModelIndex)
{
unsigned posSlot = (unsigned)distance;
unsigned numDirectBits = (unsigned)(((distance >> 1) - 1));
distance = (2 | (distance & 1));
if (posSlot < kEndPosModelIndex)
{
distance <<= numDirectBits;
prob = probs + SpecPos;
{
UInt32 m = 1;
distance++;
do
{
REV_BIT_VAR(prob, distance, m);
}
while (--numDirectBits);
distance -= m;
}
}
else
{
numDirectBits -= kNumAlignBits;
do
{
NORMALIZE
range >>= 1;
{
UInt32 t;
code -= range;
t = (0 - ((UInt32)code >> 31)); /* (UInt32)((Int32)code >> 31) */
distance = (distance << 1) + (t + 1);
code += range & t;
}
/*
distance <<= 1;
if (code >= range)
{
code -= range;
distance |= 1;
}
*/
}
while (--numDirectBits);
prob = probs + Align;
distance <<= kNumAlignBits;
{
unsigned i = 1;
REV_BIT_CONST(prob, i, 1);
REV_BIT_CONST(prob, i, 2);
REV_BIT_CONST(prob, i, 4);
REV_BIT_LAST (prob, i, 8);
distance |= i;
}
if (distance == (UInt32)0xFFFFFFFF)
{
len = kMatchSpecLenStart;
state -= kNumStates;
break;
}
}
}
rep3 = rep2;
rep2 = rep1;
rep1 = rep0;
rep0 = distance + 1;
state = (state < kNumStates + kNumLitStates) ? kNumLitStates : kNumLitStates + 3;
if (distance >= (checkDicSize == 0 ? processedPos: checkDicSize))
{
p->dicPos = dicPos;
return SZ_ERROR_DATA;
}
}
len += kMatchMinLen;
{
SizeT rem;
unsigned curLen;
SizeT pos;
if ((rem = limit - dicPos) == 0)
{
p->dicPos = dicPos;
return SZ_ERROR_DATA;
}
curLen = ((rem < len) ? (unsigned)rem : len);
pos = dicPos - rep0 + (dicPos < rep0 ? dicBufSize : 0);
processedPos += (UInt32)curLen;
len -= curLen;
if (curLen <= dicBufSize - pos)
{
Byte *dest = dic + dicPos;
ptrdiff_t src = (ptrdiff_t)pos - (ptrdiff_t)dicPos;
const Byte *lim = dest + curLen;
dicPos += (SizeT)curLen;
do
*(dest) = (Byte)*(dest + src);
while (++dest != lim);
}
else
{
do
{
dic[dicPos++] = dic[pos];
if (++pos == dicBufSize)
pos = 0;
}
while (--curLen != 0);
}
}
}
}
while (dicPos < limit && buf < bufLimit);
NORMALIZE;
p->buf = buf;
p->range = range;
p->code = code;
p->remainLen = (UInt32)len;
p->dicPos = dicPos;
p->processedPos = processedPos;
p->reps[0] = rep0;
p->reps[1] = rep1;
p->reps[2] = rep2;
p->reps[3] = rep3;
p->state = (UInt32)state;
return SZ_OK;
}