private static void LZ4_resetStream(LZ4_stream_t *state) => Mem.Zero((byte *)state, sizeof(LZ4_stream_t));
private static int LZ4_compress_fast_continue <TEndian, TArch>(LZ4_stream_t *stream, byte *source, byte *dest, int inputSize, int maxOutputSize, int acceleration = 1)
where TEndian : struct, IEndian
where TArch : unmanaged, IArch
{
var dictEnd = stream->dictionary + stream->dictSize;
Debug.WriteLine($"LZ4_compress_fast_continue (inputSize={inputSize})");
if (stream->initCheck != 0)
{
return(0); /* Uninitialized structure detected */
}
LZ4_renormDictT(stream, inputSize); /* avoid index overflow */
acceleration = Math.Max(acceleration, 1);
/* invalidate tiny dictionaries */
if (stream->dictSize - 1 < 4 && /* intentional underflow */
dictEnd != source)
{
Debug.WriteLine($"LZ4_compress_fast_continue: dictSize({stream->dictSize}) at addr:{(ulong)stream->dictionary} is too small");
stream->dictSize = 0;
stream->dictionary = source;
dictEnd = source;
}
/* Check overlapping input/dictionary space */
{
var sourceEnd = source + inputSize;
if ((sourceEnd > stream->dictionary) && (sourceEnd < dictEnd))
{
stream->dictSize = (uint)(dictEnd - sourceEnd);
if (stream->dictSize > _64KB)
{
stream->dictSize = _64KB;
}
if (stream->dictSize < 4)
{
stream->dictSize = 0;
}
stream->dictionary = dictEnd - stream->dictSize;
}
}
/* prefix mode : source data follows dictionary */
if (dictEnd == source)
{
var _ = 0;
if (stream->dictSize < _64KB && stream->dictSize < stream->currentOffset)
{
return(LZ4_compress_generic <LimitedOutput, ByU32, WithPrefix64K, DictSmall, TEndian, TArch>(stream, source, dest, inputSize, ref _, maxOutputSize, acceleration));
}
return(LZ4_compress_generic <LimitedOutput, ByU32, WithPrefix64K, NoDictIssue, TEndian, TArch>(stream, source, dest, inputSize, ref _, maxOutputSize, acceleration));
}
/* external dictionary mode */
{
int result;
var _ = 0;
if (stream->dictCtx != null)
{
/* We depend here on the fact that dictCtx'es (produced by
* LZ4_loadDict) guarantee that their tables contain no references
* to offsets between dictCtx->currentOffset - 64 KB and
* dictCtx->currentOffset - dictCtx->dictSize. This makes it safe
* to use noDictIssue even when the dict isn't a full 64 KB.
*/
if (inputSize > _4KB)
{
/* For compressing large blobs, it is faster to pay the setup
* cost to copy the dictionary's tables into the active context,
* so that the compression loop is only looking into one table.
*/
Unsafe.CopyBlock(stream, stream->dictCtx, (uint)sizeof(LZ4_stream_t));
result = LZ4_compress_generic <LimitedOutput, ByU32, UsingExtDict, NoDictIssue, TEndian, TArch>(stream, source, dest, inputSize, ref _, maxOutputSize, acceleration);
}
else
{
result = LZ4_compress_generic <LimitedOutput, ByU32, UsingDictCtx, NoDictIssue, TEndian, TArch>(stream, source, dest, inputSize, ref _, maxOutputSize, acceleration);
}
}
else
{
if ((stream->dictSize < _64KB) && (stream->dictSize < stream->currentOffset))
{
result = LZ4_compress_generic <LimitedOutput, ByU32, UsingExtDict, DictSmall, TEndian, TArch>(stream, source, dest, inputSize, ref _, maxOutputSize, acceleration);
}
else
{
result = LZ4_compress_generic <LimitedOutput, ByU32, UsingExtDict, NoDictIssue, TEndian, TArch>(stream, source, dest, inputSize, ref _, maxOutputSize, acceleration);
}
}
stream->dictionary = source;
stream->dictSize = (uint)inputSize;
return(result);
}
}
static int LZ4_compress_destSize_generic(
LZ4_stream_t *ctx, byte *src, byte *dst, int *srcSizePtr, int targetDstSize,
tableType_t tableType)
{
var ip = src;
var base_ = src;
var lowLimit = src;
var anchor = ip;
var iend = ip + *srcSizePtr;
var mflimit = iend - MFLIMIT;
var matchlimit = iend - LASTLITERALS;
var op = dst;
var oend = op + targetDstSize;
var oMaxLit = op + targetDstSize - 2 - 8 - 1;
var oMaxMatch = op + targetDstSize - (LASTLITERALS + 1);
var oMaxSeq = oMaxLit - 1;
if (targetDstSize < 1)
{
return(0);
}
if (*srcSizePtr > LZ4_MAX_INPUT_SIZE)
{
return(0);
}
if (tableType == tableType_t.byU16 && *srcSizePtr >= LZ4_64Klimit)
{
return(0);
}
if (*srcSizePtr < LZ4_minLength)
{
goto _last_literals; /* Input too small, no compression (all literals) */
}
*srcSizePtr = 0;
LZ4_putPosition(ip, ctx->hashTable, tableType, base_);
ip++;
var forwardH = LZ4_hashPosition(ip, tableType);
for (;;)
{
byte *match;
byte *token;
{
var forwardIp = ip;
var step = 1u;
var searchMatchNb = 1u << LZ4_skipTrigger;
do
{
var h = forwardH;
ip = forwardIp;
forwardIp += step;
step = searchMatchNb++ >> LZ4_skipTrigger;
if (forwardIp > mflimit)
{
goto _last_literals;
}
match = LZ4_getPositionOnHash(h, ctx->hashTable, tableType, base_);
forwardH = LZ4_hashPosition(forwardIp, tableType);
LZ4_putPositionOnHash(ip, h, ctx->hashTable, tableType, base_);
}while (
tableType != tableType_t.byU16 && match + MAX_DISTANCE < ip ||
Mem.Peek32(match) != Mem.Peek32(ip));
}
while (ip > anchor && match > lowLimit && ip[-1] == match[-1])
{
ip--;
match--;
}
{
var litLength = (uint)(ip - anchor);
token = op++;
if (op + (litLength + 240) / 255 + litLength > oMaxLit)
{
op--;
goto _last_literals;
}
if (litLength >= RUN_MASK)
{
var len = 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.WildCopy(op, anchor, op + litLength);
op += litLength;
}
_next_match:
Mem.Poke16(op, (ushort)(ip - match));
op += 2;
{
var matchLength = (int)LZ4_count(ip + MINMATCH, match + MINMATCH, matchlimit);
if (op + (matchLength + 240) / 255 > oMaxMatch)
{
matchLength = (int)(15 - 1 + (oMaxMatch - op) * 255);
}
ip += MINMATCH + matchLength;
if (matchLength >= ML_MASK)
{
*token += (byte)ML_MASK;
matchLength -= (int)ML_MASK;
while (matchLength >= 255)
{
matchLength -= 255;
*op++ = 255;
}
*op++ = (byte)matchLength;
}
else
{
*token += (byte)matchLength;
}
}
anchor = ip;
if (ip > mflimit)
{
break;
}
if (op > oMaxSeq)
{
break;
}
LZ4_putPosition(ip - 2, ctx->hashTable, tableType, base_);
match = LZ4_getPosition(ip, ctx->hashTable, tableType, base_);
LZ4_putPosition(ip, ctx->hashTable, tableType, base_);
if (match + MAX_DISTANCE >= ip && Mem.Peek32(match) == Mem.Peek32(ip))
{
token = op++;
*token = 0;
goto _next_match;
}
forwardH = LZ4_hashPosition(++ip, tableType);
}
_last_literals:
{
var lastRunSize = (int)(iend - anchor);
if (op + 1 + (lastRunSize + 240) / 255 + lastRunSize > oend)
{
lastRunSize = (int)(oend - op) - 1;
lastRunSize -= (lastRunSize + 240) / 255;
}
ip = anchor + lastRunSize;
if (lastRunSize >= RUN_MASK)
{
var accumulator = lastRunSize - RUN_MASK;
*op++ = (byte)(RUN_MASK << ML_BITS);
for (; accumulator >= 255; accumulator -= 255)
{
*op++ = 255;
}
*op++ = (byte)accumulator;
}
else
{
*op++ = (byte)(lastRunSize << ML_BITS);
}
Mem.Copy(op, anchor, lastRunSize);
op += lastRunSize;
}
*srcSizePtr = (int)(ip - src);
return((int)(op - dst));
}
public static int LZ4_compress_fast_continue(
LZ4_stream_t *streamPtr, byte *source, byte *dest, int inputSize, int maxOutputSize,
int acceleration)
{
var dictEnd = streamPtr->dictionary + streamPtr->dictSize;
var smallest = source;
if (streamPtr->initCheck != 0)
{
return(0); /* Uninitialized structure detected */
}
if (streamPtr->dictSize > 0 && smallest > dictEnd)
{
smallest = dictEnd;
}
LZ4_renormDictT(streamPtr, smallest);
if (acceleration < 1)
{
acceleration = ACCELERATION_DEFAULT;
}
/* Check overlapping input/dictionary space */
{
var sourceEnd = source + inputSize;
if (sourceEnd > streamPtr->dictionary && sourceEnd < dictEnd)
{
streamPtr->dictSize = (uint)(dictEnd - sourceEnd);
if (streamPtr->dictSize > 64 * KB)
{
streamPtr->dictSize = 64 * KB;
}
if (streamPtr->dictSize < 4)
{
streamPtr->dictSize = 0;
}
streamPtr->dictionary = dictEnd - streamPtr->dictSize;
}
}
var dictIssue =
streamPtr->dictSize < 64 * KB && streamPtr->dictSize < streamPtr->currentOffset
? dictIssue_directive.dictSmall
: dictIssue_directive.noDictIssue;
var dictMode =
dictEnd == source
? dict_directive.withPrefix64k
: dict_directive.usingExtDict;
var result = LZ4_compress_generic(
streamPtr,
source,
dest,
inputSize,
maxOutputSize,
limitedOutput_directive.limitedOutput,
tableType_t.byU32,
dictMode,
dictIssue,
(uint)acceleration);
if (dictMode == dict_directive.withPrefix64k)
{
/* prefix mode : source data follows dictionary */
streamPtr->dictSize += (uint)inputSize;
streamPtr->currentOffset += (uint)inputSize;
}
else
{
/* external dictionary mode */
streamPtr->dictionary = source;
streamPtr->dictSize = (uint)inputSize;
streamPtr->currentOffset += (uint)inputSize;
}
return(result);
}
public static int LZ4_compress_generic(
LZ4_stream_t *cctx,
byte *source,
byte *dest,
int inputSize,
int maxOutputSize,
limitedOutput_directive outputLimited,
tableType_t tableType,
dict_directive dict,
dictIssue_directive dictIssue,
uint acceleration)
{
var ip = source;
byte *ibase;
byte *lowLimit;
var lowRefLimit = ip - cctx->dictSize;
var dictionary = cctx->dictionary;
var dictEnd = dictionary + cctx->dictSize;
var dictDelta = dictEnd - source;
var anchor = source;
var iend = ip + inputSize;
var mflimit = iend - MFLIMIT;
var matchlimit = iend - LASTLITERALS;
var op = dest;
var olimit = op + maxOutputSize;
if (inputSize > LZ4_MAX_INPUT_SIZE)
{
return(0);
}
switch (dict)
{
case dict_directive.withPrefix64k:
ibase = source - cctx->currentOffset;
lowLimit = source - cctx->dictSize;
break;
case dict_directive.usingExtDict:
ibase = source - cctx->currentOffset;
lowLimit = source;
break;
default:
ibase = source;
lowLimit = source;
break;
}
if (tableType == tableType_t.byU16 && inputSize >= LZ4_64Klimit)
{
return(0);
}
if (inputSize < LZ4_minLength)
{
goto _last_literals;
}
LZ4_putPosition(ip, cctx->hashTable, tableType, ibase);
ip++;
var forwardH = LZ4_hashPosition(ip, tableType);
for (;;)
{
var refDelta = 0L;
byte *match;
byte *token;
{
var forwardIp = ip;
var step = 1u;
var searchMatchNb = acceleration << LZ4_skipTrigger;
do
{
var h = forwardH;
ip = forwardIp;
forwardIp += step;
step = searchMatchNb++ >> LZ4_skipTrigger;
if (forwardIp > mflimit)
{
goto _last_literals;
}
match = LZ4_getPositionOnHash(h, cctx->hashTable, tableType, ibase);
if (dict == dict_directive.usingExtDict)
{
if (match < source)
{
refDelta = dictDelta;
lowLimit = dictionary;
}
else
{
refDelta = 0;
lowLimit = source;
}
}
forwardH = LZ4_hashPosition(forwardIp, tableType);
LZ4_putPositionOnHash(ip, h, cctx->hashTable, tableType, ibase);
}while (
dictIssue == dictIssue_directive.dictSmall && match < lowRefLimit ||
tableType != tableType_t.byU16 && match + MAX_DISTANCE < ip ||
Mem.Peek32(match + refDelta) != Mem.Peek32(ip));
}
while (ip > anchor && match + refDelta > lowLimit && ip[-1] == match[refDelta - 1])
{
ip--;
match--;
}
{
var litLength = (uint)(ip - anchor);
token = op++;
if (outputLimited == limitedOutput_directive.limitedOutput &&
op + litLength + (2 + 1 + LASTLITERALS) + litLength / 255 > olimit)
{
return(0);
}
if (litLength >= RUN_MASK)
{
var 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.WildCopy(op, anchor, op + litLength);
op += litLength;
}
_next_match:
Mem.Poke16(op, (ushort)(ip - match));
op += 2;
{
uint matchCode;
if (dict == dict_directive.usingExtDict && lowLimit == dictionary)
{
match += refDelta;
var limit = ip + (dictEnd - match);
if (limit > matchlimit)
{
limit = matchlimit;
}
matchCode = LZ4_count(ip + MINMATCH, match + MINMATCH, limit);
ip += MINMATCH + matchCode;
if (ip == limit)
{
var more = LZ4_count(ip, source, matchlimit);
matchCode += more;
ip += more;
}
}
else
{
matchCode = LZ4_count(ip + MINMATCH, match + MINMATCH, matchlimit);
ip += MINMATCH + matchCode;
}
if (outputLimited == limitedOutput_directive.limitedOutput &&
op + (1 + LASTLITERALS) + (matchCode >> 8) > olimit)
{
return(0);
}
if (matchCode >= ML_MASK)
{
*token += (byte)ML_MASK;
matchCode -= ML_MASK;
Mem.Poke32(op, 0xFFFFFFFF);
while (matchCode >= 4 * 255)
{
op += 4;
Mem.Poke32(op, 0xFFFFFFFF);
matchCode -= 4 * 255;
}
op += matchCode / 255;
*op++ = (byte)(matchCode % 255);
}
else
{
*token += (byte)matchCode;
}
}
anchor = ip;
if (ip > mflimit)
{
break;
}
LZ4_putPosition(ip - 2, cctx->hashTable, tableType, ibase);
match = LZ4_getPosition(ip, cctx->hashTable, tableType, ibase);
if (dict == dict_directive.usingExtDict)
{
if (match < source)
{
refDelta = dictDelta;
lowLimit = dictionary;
}
else
{
refDelta = 0;
lowLimit = source;
}
}
LZ4_putPosition(ip, cctx->hashTable, tableType, ibase);
if ((dictIssue != dictIssue_directive.dictSmall || match >= lowRefLimit) &&
match + MAX_DISTANCE >= ip &&
Mem.Peek32(match + refDelta) == Mem.Peek32(ip))
{
token = op++;
*token = 0;
goto _next_match;
}
forwardH = LZ4_hashPosition(++ip, tableType);
}
_last_literals:
{
var lastRun = (int)(iend - anchor);
if (outputLimited == limitedOutput_directive.limitedOutput &&
op - dest + lastRun + 1 + (lastRun + 255 - RUN_MASK) / 255 > (uint)maxOutputSize)
{
return(0);
}
if (lastRun >= RUN_MASK)
{
var accumulator = (int)(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, lastRun);
op += lastRun;
}
return((int)(op - dest));
}
