protected static uint LZ4_hashPosition(void *p, tableType_t tableType)
{
#if !BIT32
if (tableType != tableType_t.byU16)
{
return(LZ4_hash5(Mem.PeekW(p), tableType));
}
#endif
return(LZ4_hash4(Mem.Peek4(p), tableType));
}
protected static uint LZ4_count(byte *pIn, byte *pMatch, byte *pInLimit)
{
const int STEPSIZE = ALGORITHM_ARCH;
var pStart = pIn;
if (pIn < pInLimit - (STEPSIZE - 1))
{
var diff = Mem.PeekW(pMatch) ^ Mem.PeekW(pIn);
if (diff != 0)
{
return(LZ4_NbCommonBytes(diff));
}
pIn += STEPSIZE;
pMatch += STEPSIZE;
}
while (pIn < pInLimit - (STEPSIZE - 1))
{
var diff = Mem.PeekW(pMatch) ^ Mem.PeekW(pIn);
if (diff != 0)
{
return((uint)(pIn + LZ4_NbCommonBytes(diff) - pStart));
}
pIn += STEPSIZE;
pMatch += STEPSIZE;
}
#if !BIT32
if (pIn < pInLimit - 3 && Mem.Peek4(pMatch) == Mem.Peek4(pIn))
{
pIn += 4;
pMatch += 4;
}
#endif
if (pIn < pInLimit - 1 && Mem.Peek2(pMatch) == Mem.Peek2(pIn))
{
pIn += 2;
pMatch += 2;
}
if (pIn < pInLimit && *pMatch == *pIn)
{
pIn++;
}
return((uint)(pIn - pStart));
}
protected static int LZ4_compress_generic(
LZ4_stream_t *cctx,
byte *source,
byte *dest,
int inputSize,
int *inputConsumed, /* only written when outputDirective == fillOutput */
int maxOutputSize,
limitedOutput_directive outputDirective,
tableType_t tableType,
dict_directive dictDirective,
dictIssue_directive dictIssue,
int acceleration)
{
int result;
byte *ip = (byte *)source;
uint startIndex = cctx->currentOffset;
byte * @base = (byte *)source - startIndex;
byte * lowLimit;
LZ4_stream_t *dictCtx = (LZ4_stream_t *)cctx->dictCtx;
byte * dictionary =
dictDirective == dict_directive.usingDictCtx ? dictCtx->dictionary
: cctx->dictionary;
uint dictSize =
dictDirective == dict_directive.usingDictCtx ? dictCtx->dictSize : cctx->dictSize;
uint dictDelta = (dictDirective == dict_directive.usingDictCtx)
? startIndex - dictCtx->currentOffset : 0;
bool maybe_extMem = (dictDirective == dict_directive.usingExtDict) ||
(dictDirective == dict_directive.usingDictCtx);
uint prefixIdxLimit = startIndex - dictSize;
byte *dictEnd = dictionary + dictSize;
byte *anchor = (byte *)source;
byte *iend = ip + inputSize;
byte *mflimitPlusOne = iend - MFLIMIT + 1;
byte *matchlimit = iend - LASTLITERALS;
/* the dictCtx currentOffset is indexed on the start of the dictionary,
* while a dictionary in the current context precedes the currentOffset */
byte *dictBase = (dictDirective == dict_directive.usingDictCtx) ?
dictionary + dictSize - dictCtx->currentOffset :
dictionary + dictSize - startIndex;
byte *op = (byte *)dest;
byte *olimit = op + maxOutputSize;
uint offset = 0;
uint forwardH;
if (outputDirective == limitedOutput_directive.fillOutput && maxOutputSize < 1)
{
return(0);
}
if ((uint)inputSize > (uint)LZ4_MAX_INPUT_SIZE)
{
return(0);
}
if ((tableType == tableType_t.byU16) && (inputSize >= LZ4_64Klimit))
{
return(0);
}
if (tableType == tableType_t.byPtr)
{
Assert(dictDirective == dict_directive.noDict);
}
Assert(acceleration >= 1);
lowLimit = (byte *)source
- (dictDirective == dict_directive.withPrefix64k ? dictSize : 0);
/* Update context state */
if (dictDirective == dict_directive.usingDictCtx)
{
/* Subsequent linked blocks can't use the dictionary. */
/* Instead, they use the block we just compressed. */
cctx->dictCtx = null;
cctx->dictSize = (uint)inputSize;
}
else
{
cctx->dictSize += (uint)inputSize;
}
cctx->currentOffset += (uint)inputSize;
cctx->tableType = tableType;
if (inputSize < LZ4_minLength)
{
goto _last_literals;
}
/* First Byte */
LZ4_putPosition(ip, cctx->hashTable, tableType, @base);
ip++;
forwardH = LZ4_hashPosition(ip, tableType);
/* Main Loop */
for (;;)
{
byte *match;
byte *token;
byte *filledIp;
/* Find a match */
if (tableType == tableType_t.byPtr)
{
byte *forwardIp = ip;
int step = 1;
int searchMatchNb = acceleration << LZ4_skipTrigger;
do
{
uint h = forwardH;
ip = forwardIp;
forwardIp += step;
step = (searchMatchNb++ >> LZ4_skipTrigger);
if ((forwardIp > mflimitPlusOne))
{
goto _last_literals;
}
Assert(ip < mflimitPlusOne);
match = LZ4_getPositionOnHash(h, cctx->hashTable, tableType, @base);
forwardH = LZ4_hashPosition(forwardIp, tableType);
LZ4_putPositionOnHash(ip, h, cctx->hashTable, tableType, @base);
}while ((match + LZ4_DISTANCE_MAX < ip) || (Mem.Peek4(match) != Mem.Peek4(ip)));
}
else
{
/* byU32, byU16 */
byte *forwardIp = ip;
int step = 1;
int searchMatchNb = acceleration << LZ4_skipTrigger;
do
{
uint h = forwardH;
uint current = (uint)(forwardIp - @base);
uint matchIndex = LZ4_getIndexOnHash(h, cctx->hashTable, tableType);
Assert(matchIndex <= current);
Assert(forwardIp - @base < (2 * GB - 1));
ip = forwardIp;
forwardIp += step;
step = (searchMatchNb++ >> LZ4_skipTrigger);
if ((forwardIp > mflimitPlusOne))
{
goto _last_literals;
}
Assert(ip < mflimitPlusOne);
if (dictDirective == dict_directive.usingDictCtx)
{
if (matchIndex < startIndex)
{
Assert(tableType == tableType_t.byU32);
matchIndex = LZ4_getIndexOnHash(
h, dictCtx->hashTable, tableType_t.byU32);
match = dictBase + matchIndex;
matchIndex += dictDelta;
lowLimit = dictionary;
}
else
{
match = @base + matchIndex;
lowLimit = (byte *)source;
}
}
else if (dictDirective == dict_directive.usingExtDict)
{
if (matchIndex < startIndex)
{
Assert(startIndex - matchIndex >= MINMATCH);
match = dictBase + matchIndex;
lowLimit = dictionary;
}
else
{
match = @base + matchIndex;
lowLimit = (byte *)source;
}
}
else
{
match = @base + matchIndex;
}
forwardH = LZ4_hashPosition(forwardIp, tableType);
LZ4_putIndexOnHash(current, h, cctx->hashTable, tableType);
if ((dictIssue == dictIssue_directive.dictSmall) &&
(matchIndex < prefixIdxLimit))
{
continue;
}
Assert(matchIndex < current);
if (((tableType != tableType_t.byU16) ||
(LZ4_DISTANCE_MAX < LZ4_DISTANCE_ABSOLUTE_MAX)) &&
(matchIndex + LZ4_DISTANCE_MAX < current))
{
continue;
}
Assert((current - matchIndex) <= LZ4_DISTANCE_MAX);
if (Mem.Peek4(match) == Mem.Peek4(ip))
{
if (maybe_extMem)
{
offset = current - matchIndex;
}
break;
}
}while (true);
}
filledIp = ip;
while (((ip > anchor) & (match > lowLimit)) && ((ip[-1] == match[-1])))
{
ip--;
match--;
}
{
var litLength = (uint)(ip - anchor);
token = op++;
if ((outputDirective == limitedOutput_directive.limitedOutput) &&
((op + litLength + (2 + 1 + LASTLITERALS) + (litLength / 255) > olimit)))
{
return(0);
}
if ((outputDirective == limitedOutput_directive.fillOutput) &&
((op + (litLength + 240) / 255 + litLength + 2 + 1 + MFLIMIT - MINMATCH
> olimit)))
{
op--;
goto _last_literals;
}
if (litLength >= RUN_MASK)
{
int len = (int)(litLength - RUN_MASK);
*token = (byte)(RUN_MASK << ML_BITS);
for (; len >= 255; len -= 255)
{
*op++ = 255;
}
*op++ = (byte)len;
}
else
{
*token = (byte)(litLength << ML_BITS);
}
Mem.WildCopy8(op, anchor, op + litLength);
op += litLength;
}
_next_match:
/* at this stage, the following variables must be correctly set :
* - ip : at start of LZ operation
* - match : at start of previous pattern occurence; can be within current prefix, or within extDict
* - offset : if maybe_ext_memSegment==1 (constant)
* - lowLimit : must be == dictionary to mean "match is within extDict"; must be == source otherwise
* - token and *token : position to write 4-bits for match length; higher 4-bits for literal length supposed already written
*/
if ((outputDirective == limitedOutput_directive.fillOutput) &&
(op + 2 + 1 + MFLIMIT - MINMATCH > olimit))
{
/* the match was too close to the end, rewind and go to last literals */
op = token;
goto _last_literals;
}
/* Encode Offset */
if (maybe_extMem)
{
/* static test */
Assert(offset <= LZ4_DISTANCE_MAX && offset > 0);
Mem.Poke2(op, (ushort)offset);
op += 2;
}
else
{
Assert(ip - match <= LZ4_DISTANCE_MAX);
Mem.Poke2(op, (ushort)(ip - match));
op += 2;
}
/* Encode MatchLength */
{
uint matchCode;
if ((dictDirective == dict_directive.usingExtDict ||
dictDirective == dict_directive.usingDictCtx) &&
(lowLimit == dictionary) /* match within extDict */)
{
byte *limit = ip + (dictEnd - match);
Assert(dictEnd > match);
if (limit > matchlimit)
{
limit = matchlimit;
}
matchCode = LZ4_count(ip + MINMATCH, match + MINMATCH, limit);
ip += (uint)matchCode + MINMATCH;
if (ip == limit)
{
uint more = LZ4_count(limit, (byte *)source, matchlimit);
matchCode += more;
ip += more;
}
}
else
{
matchCode = LZ4_count(ip + MINMATCH, match + MINMATCH, matchlimit);
ip += (uint)matchCode + MINMATCH;
}
if ((outputDirective != 0) &&
((op + (1 + LASTLITERALS) + (matchCode + 240) / 255 > olimit)))
{
if (outputDirective == limitedOutput_directive.fillOutput)
{
/* Match description too long : reduce it */
uint newMatchCode =
15 - 1 + ((uint)(olimit - op) - 1 - LASTLITERALS) * 255;
ip -= matchCode - newMatchCode;
Assert(newMatchCode < matchCode);
matchCode = newMatchCode;
if ((ip <= filledIp))
{
/* We have already filled up to filledIp so if ip ends up less than filledIp
* we have positions in the hash table beyond the current position. This is
* a problem if we reuse the hash table. So we have to remove these positions
* from the hash table.
*/
byte *ptr;
for (ptr = ip; ptr <= filledIp; ++ptr)
{
uint h = LZ4_hashPosition(ptr, tableType);
LZ4_clearHash(h, cctx->hashTable, tableType);
}
}
}
else
{
Assert(outputDirective == limitedOutput_directive.limitedOutput);
return(0);
}
}
if (matchCode >= ML_MASK)
{
*token += (byte)ML_MASK; //!!!
matchCode -= ML_MASK;
Mem.Poke4(op, 0xFFFFFFFF);
while (matchCode >= 4 * 255)
{
op += 4;
Mem.Poke4(op, 0xFFFFFFFF);
matchCode -= 4 * 255;
}
op += matchCode / 255;
*op++ = (byte)(matchCode % 255);
}
else
{
*token += (byte)(matchCode);
}
}
/* Ensure we have enough space for the last literals. */
Assert(
!(outputDirective == limitedOutput_directive.fillOutput &&
op + 1 + LASTLITERALS > olimit));
anchor = ip;
/* Test end of chunk */
if (ip >= mflimitPlusOne)
{
break;
}
/* Fill table */
LZ4_putPosition(ip - 2, cctx->hashTable, tableType, @base);
/* Test next position */
if (tableType == tableType_t.byPtr)
{
match = LZ4_getPosition(ip, cctx->hashTable, tableType, @base);
LZ4_putPosition(ip, cctx->hashTable, tableType, @base);
if ((match + LZ4_DISTANCE_MAX >= ip) && (Mem.Peek4(match) == Mem.Peek4(ip)))
{
token = op++;
*token = 0;
goto _next_match;
}
}
else
{
/* byU32, byU16 */
uint h = LZ4_hashPosition(ip, tableType);
uint current = (uint)(ip - @base);
uint matchIndex = LZ4_getIndexOnHash(h, cctx->hashTable, tableType);
Assert(matchIndex < current);
if (dictDirective == dict_directive.usingDictCtx)
{
if (matchIndex < startIndex)
{
matchIndex = LZ4_getIndexOnHash(
h, dictCtx->hashTable, tableType_t.byU32);
match = dictBase + matchIndex;
lowLimit = dictionary;
matchIndex += dictDelta;
}
else
{
match = @base + matchIndex;
lowLimit = (byte *)source;
}
}
else if (dictDirective == dict_directive.usingExtDict)
{
if (matchIndex < startIndex)
{
match = dictBase + matchIndex;
lowLimit = dictionary;
}
else
{
match = @base + matchIndex;
lowLimit = (byte *)source;
}
}
else
{
match = @base + matchIndex;
}
LZ4_putIndexOnHash(current, h, cctx->hashTable, tableType);
Assert(matchIndex < current);
if (((dictIssue != dictIssue_directive.dictSmall) ||
(matchIndex >= prefixIdxLimit)) &&
(((tableType == tableType_t.byU16) &&
(LZ4_DISTANCE_MAX == LZ4_DISTANCE_ABSOLUTE_MAX)) ||
(matchIndex + LZ4_DISTANCE_MAX >= current)) &&
(Mem.Peek4(match) == Mem.Peek4(ip)))
{
token = op++;
*token = 0;
if (maybe_extMem)
{
offset = current - matchIndex;
}
goto _next_match;
}
}
forwardH = LZ4_hashPosition(++ip, tableType);
}
_last_literals:
{
var lastRun = (size_t)(iend - anchor);
if ((outputDirective != 0) &&
(op + lastRun + 1 + ((lastRun + 255 - RUN_MASK) / 255) > olimit))
{
if (outputDirective == limitedOutput_directive.fillOutput)
{
Assert(olimit >= op);
lastRun = (size_t)(olimit - op) - 1;
lastRun -= (lastRun + 240) / 255;
}
else
{
Assert(outputDirective == limitedOutput_directive.limitedOutput);
return(0);
}
}
if (lastRun >= RUN_MASK)
{
var accumulator = (size_t)(lastRun - RUN_MASK);
*op++ = (byte)(RUN_MASK << ML_BITS);
for (; accumulator >= 255; accumulator -= 255)
{
*op++ = 255;
}
*op++ = (byte)accumulator;
}
else
{
*op++ = (byte)(lastRun << ML_BITS);
}
Mem.Copy(op, anchor, (int)lastRun);
ip = anchor + lastRun;
op += lastRun;
}
if (outputDirective == limitedOutput_directive.fillOutput)
{
*inputConsumed = (int)(((byte *)ip) - source);
}
result = (int)(((byte *)op) - dest);
Assert(result > 0);
return(result);
}
