public static int DecompressGeneric(byte *src, byte *dst, int srcSize, int outputSize,
EndConditionDirective endOnInput, EarlyEndDirective partialDecoding,
int targetOutputSize, DictDirective dict, byte *lowPrefix, byte *dictStart, int dictSize)
{
byte *ip = src;
byte *iend = ip + srcSize;
byte *op = dst;
byte *oend = op + outputSize;
byte *oexit = op + targetOutputSize;
byte *dictEnd = dictStart + dictSize;
bool safeDecode = endOnInput == EndConditionDirective.EndOnInputSize;
bool checkOffset = safeDecode && dictSize < 64 * KB;
if ((partialDecoding != EarlyEndDirective.Full) && (oexit > oend - MFLimit))
{
oexit = oend - MFLimit;
}
if ((endOnInput == EndConditionDirective.EndOnInputSize) && (outputSize == 0))
{
return(srcSize == 1 && *ip == 0 ? 0 : -1);
}
if ((endOnInput != EndConditionDirective.EndOnInputSize) && (outputSize == 0))
{
return(*ip == 0 ? 1 : -1);
}
for (; ;)
{
int length;
uint token = *ip++;
if ((ip + 14 + 2 <= iend) &&
(op + 14 + 18 <= oend) &&
(token < 15 << MLBits) &&
((token & MLMask) != 15))
{
int ll = (int)(token >> MLBits);
int off = LZ4MemoryHelper.Peek16(ip + ll);
byte *matchPtr = op + ll - off;
if (off >= 18 && matchPtr >= lowPrefix)
{
int ml = (int)((token & MLMask) + MinMatch);
LZ4MemoryHelper.Copy16(op, ip);
op += ll;
ip += ll + 2;
LZ4MemoryHelper.Copy18(op, matchPtr);
op += ml;
continue;
}
}
if ((length = (int)(token >> MLBits)) == RunMask)
{
uint s;
do
{
s = *ip++;
length += (int)s;
}while (
(endOnInput != EndConditionDirective.EndOnInputSize || ip < iend - RunMask) &&
(s == 255));
if (safeDecode && op + length < op)
{
goto _output_error;
}
if (safeDecode && ip + length < ip)
{
goto _output_error;
}
}
byte *cpy = op + length;
if ((endOnInput == EndConditionDirective.EndOnInputSize) &&
((cpy > (partialDecoding == EarlyEndDirective.Partial ? oexit : oend - MFLimit)) ||
(ip + length > iend - (2 + 1 + LastLiterals))) ||
(endOnInput != EndConditionDirective.EndOnInputSize) && (cpy > oend - WildCopyLength))
{
if (partialDecoding == EarlyEndDirective.Partial)
{
if (cpy > oend)
{
goto _output_error;
}
if ((endOnInput == EndConditionDirective.EndOnInputSize) && (ip + length > iend))
{
goto _output_error;
}
}
else
{
if ((endOnInput != EndConditionDirective.EndOnInputSize) && (cpy != oend))
{
goto _output_error;
}
if ((endOnInput == EndConditionDirective.EndOnInputSize) &&
(ip + length != iend || cpy > oend))
{
goto _output_error;
}
}
LZ4MemoryHelper.Copy(op, ip, length);
ip += length;
op += length;
break;
}
LZ4MemoryHelper.WildCopy(op, ip, cpy);
ip += length;
op = cpy;
int offset = LZ4MemoryHelper.Peek16(ip);
ip += 2;
byte *match = op - offset;
if (checkOffset && match + dictSize < lowPrefix)
{
goto _output_error;
}
LZ4MemoryHelper.Poke32(op, (uint)offset);
length = (int)(token & MLMask);
if (length == MLMask)
{
uint s;
do
{
s = *ip++;
if ((endOnInput == EndConditionDirective.EndOnInputSize) && (ip > iend - LastLiterals))
{
goto _output_error;
}
length += (int)s;
}while (s == 255);
if (safeDecode && (op + length < op))
{
goto _output_error;
}
}
length += MinMatch;
if ((dict == DictDirective.UsingExtDict) && (match < lowPrefix))
{
if (op + length > oend - LastLiterals)
{
goto _output_error;
}
if (length <= lowPrefix - match)
{
LZ4MemoryHelper.Move(op, dictEnd - (lowPrefix - match), length);
op += length;
}
else
{
int copySize = (int)(lowPrefix - match);
int restSize = length - copySize;
LZ4MemoryHelper.Copy(op, dictEnd - copySize, copySize);
op += copySize;
if (restSize > (int)(op - lowPrefix))
{
byte *endOfMatch = op + restSize;
byte *copyFrom = lowPrefix;
while (op < endOfMatch)
{
*op++ = *copyFrom++;
}
}
else
{
LZ4MemoryHelper.Copy(op, lowPrefix, restSize);
op += restSize;
}
}
continue;
}
cpy = op + length;
if (offset < 8)
{
op[0] = match[0];
op[1] = match[1];
op[2] = match[2];
op[3] = match[3];
match += _inc32table[offset];
LZ4MemoryHelper.Copy(op + 4, match, 4);
match -= _dec64table[offset];
}
else
{
LZ4MemoryHelper.Copy8(op, match);
match += 8;
}
op += 8;
if (cpy > oend - 12)
{
byte *oCopyLimit = oend - (WildCopyLength - 1);
if (cpy > oend - LastLiterals)
{
goto _output_error;
}
if (op < oCopyLimit)
{
LZ4MemoryHelper.WildCopy(op, match, oCopyLimit);
match += oCopyLimit - op;
op = oCopyLimit;
}
while (op < cpy)
{
*op++ = *match++;
}
}
else
{
LZ4MemoryHelper.Copy8(op, match);
if (length > 16)
{
LZ4MemoryHelper.WildCopy(op + 8, match + 8, cpy);
}
}
op = cpy; // correction
}
// end of decoding
if (endOnInput == EndConditionDirective.EndOnInputSize)
{
return((int)(op - dst)); // Nb of output bytes decoded
}
return((int)(ip - src)); // Nb of input bytes read
// Overflow error detected
_output_error:
return((int)-(ip - src) - 1);
}
