public static int LZ4_decompress_generic(
byte *src,
byte *dst,
int srcSize,
int outputSize,
endCondition_directive endOnInput,
earlyEnd_directive partialDecoding,
int targetOutputSize,
dict_directive dict,
byte *lowPrefix,
byte *dictStart,
int dictSize)
{
var ip = src;
var iend = ip + srcSize;
var op = dst;
var oend = op + outputSize;
var oexit = op + targetOutputSize;
var dictEnd = dictStart + dictSize;
var safeDecode = endOnInput == endCondition_directive.endOnInputSize;
var checkOffset = safeDecode && dictSize < 64 * KB;
if (partialDecoding != earlyEnd_directive.full && oexit > oend - MFLIMIT)
{
oexit = oend - MFLIMIT;
}
if (endOnInput == endCondition_directive.endOnInputSize && outputSize == 0)
{
return(srcSize == 1 && *ip == 0 ? 0 : -1);
}
if (endOnInput != endCondition_directive.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 << ML_BITS &&
(token & ML_MASK) != 15)
{
var ll = (int)(token >> ML_BITS);
int off = Mem.Peek16(ip + ll);
var matchPtr = op + ll - off;
if (off >= 18 && matchPtr >= lowPrefix)
{
var ml = (int)((token & ML_MASK) + MINMATCH);
Mem.Copy16(op, ip);
op += ll;
ip += ll + 2;
Mem.Copy18(op, matchPtr);
op += ml;
continue;
}
}
if ((length = (int)(token >> ML_BITS)) == RUN_MASK)
{
uint s;
do
{
s = *ip++;
length += (int)s;
}while (
(endOnInput != endCondition_directive.endOnInputSize || ip < iend - RUN_MASK) &&
s == 255);
if (safeDecode && op + length < op)
{
goto _output_error;
}
if (safeDecode && ip + length < ip)
{
goto _output_error;
}
}
var cpy = op + length;
if (endOnInput == endCondition_directive.endOnInputSize &&
(
cpy > (partialDecoding == earlyEnd_directive.partial ? oexit : oend - MFLIMIT) ||
ip + length > iend - (2 + 1 + LASTLITERALS)
) ||
endOnInput != endCondition_directive.endOnInputSize && cpy > oend - WILDCOPYLENGTH)
{
if (partialDecoding == earlyEnd_directive.partial)
{
if (cpy > oend)
{
goto _output_error;
}
if (endOnInput == endCondition_directive.endOnInputSize && ip + length > iend)
{
goto _output_error;
}
}
else
{
if (endOnInput != endCondition_directive.endOnInputSize && cpy != oend)
{
goto _output_error;
}
if (endOnInput == endCondition_directive.endOnInputSize &&
(ip + length != iend || cpy > oend))
{
goto _output_error;
}
}
Mem.Copy(op, ip, length);
ip += length;
op += length;
break;
}
Mem.WildCopy(op, ip, cpy);
ip += length;
op = cpy;
int offset = Mem.Peek16(ip);
ip += 2;
var match = op - offset;
if (checkOffset && match + dictSize < lowPrefix)
{
goto _output_error;
}
Mem.Poke32(op, (uint)offset);
length = (int)(token & ML_MASK);
if (length == ML_MASK)
{
uint s;
do
{
s = *ip++;
if ((endOnInput == endCondition_directive.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 == dict_directive.usingExtDict && match < lowPrefix)
{
if (op + length > oend - LASTLITERALS)
{
goto _output_error;
}
if (length <= lowPrefix - match)
{
Mem.Move(op, dictEnd - (lowPrefix - match), length);
op += length;
}
else
{
var copySize = (int)(lowPrefix - match);
var restSize = length - copySize;
Mem.Copy(op, dictEnd - copySize, copySize);
op += copySize;
if (restSize > (int)(op - lowPrefix))
{
var endOfMatch = op + restSize;
var copyFrom = lowPrefix;
while (op < endOfMatch)
{
*op++ = *copyFrom++;
}
}
else
{
Mem.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];
Mem.Copy(op + 4, match, 4);
match -= dec64table[offset];
}
else
{
Mem.Copy8(op, match);
match += 8;
}
op += 8;
if (cpy > oend - 12)
{
var oCopyLimit = oend - (WILDCOPYLENGTH - 1);
if (cpy > oend - LASTLITERALS)
{
goto _output_error;
}
if (op < oCopyLimit)
{
Mem.WildCopy(op, match, oCopyLimit);
match += oCopyLimit - op;
op = oCopyLimit;
}
while (op < cpy)
{
*op++ = *match++;
}
}
else
{
Mem.Copy8(op, match);
if (length > 16)
{
Mem.WildCopy(op + 8, match + 8, cpy);
}
}
op = cpy; /* correction */
}
/* end of decoding */
if (endOnInput == endCondition_directive.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);
}