private static void LZ4_memcpy_using_offset_base(
byte *dstPtr, byte *srcPtr, byte *dstEnd, uint offset)
{
if (offset < 8)
{
dstPtr[0] = srcPtr[0];
dstPtr[1] = srcPtr[1];
dstPtr[2] = srcPtr[2];
dstPtr[3] = srcPtr[3];
srcPtr += inc32table[offset];
Mem.Copy4(dstPtr + 4, srcPtr);
srcPtr -= dec64table[offset];
dstPtr += 8;
}
else
{
Mem.Copy8(dstPtr, srcPtr);
dstPtr += 8;
srcPtr += 8;
}
Mem.WildCopy8(dstPtr, srcPtr, dstEnd);
}
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);
}
public static int LZ4_decompress_generic(
byte *src,
byte *dst,
int srcSize,
int outputSize,
bool endOnInput, // endCondition_directive
bool partialDecoding, // earlyEnd_directive
dict_directive dict,
byte *lowPrefix,
byte *dictStart,
size_t dictSize)
{
if (src == null)
{
return(-1);
}
{
byte *ip = (byte *)src;
byte *iend = ip + srcSize;
byte *op = (byte *)dst;
byte *oend = op + outputSize;
byte *cpy;
byte *dictEnd = (dictStart == null) ? null : dictStart + dictSize;
bool safeDecode = endOnInput;
bool checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB)));
/* Set up the "end" pointers for the shortcut. */
byte *shortiend = iend - (endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/;
byte *shortoend = oend - (endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/;
byte * match;
size_t offset;
uint token;
size_t length;
/* Special cases */
Assert(lowPrefix <= op);
if ((endOnInput) && ((outputSize == 0)))
{
/* Empty output buffer */
if (partialDecoding)
{
return(0);
}
return(((srcSize == 1) && (*ip == 0)) ? 0 : -1);
}
if ((!endOnInput) && ((outputSize == 0)))
{
return(*ip == 0 ? 1 : -1);
}
if ((endOnInput) && (srcSize == 0))
{
return(-1);
}
/* Main Loop : decode remaining sequences where output < FASTLOOP_SAFE_DISTANCE */
while (true)
{
token = *ip++;
length = (size_t)(token >> ML_BITS); /* literal length */
Assert(!endOnInput || ip <= iend); /* ip < iend before the increment */
/* A two-stage shortcut for the most common case:
* 1) If the literal length is 0..14, and there is enough space,
* enter the shortcut and copy 16 bytes on behalf of the literals
* (in the fast mode, only 8 bytes can be safely copied this way).
* 2) Further if the match length is 4..18, copy 18 bytes in a similar
* manner; but we ensure that there's enough space in the output for
* those 18 bytes earlier, upon entering the shortcut (in other words,
* there is a combined check for both stages).
*/
if ((endOnInput ? length != RUN_MASK : length <= 8)
/* strictly "less than" on input, to re-enter the loop with at least one byte */
&& ((!endOnInput || ip < shortiend) & (op <= shortoend)))
{
/* Copy the literals */
if (endOnInput)
{
Mem.Copy16(op, ip);
}
else
{
Mem.Copy8(op, ip);
}
// Mem.Copy(op, ip, endOnInput ? 16 : 8);
op += length;
ip += length;
/* The second stage: prepare for match copying, decode full info.
* If it doesn't work out, the info won't be wasted. */
length = token & ML_MASK; /* match length */
offset = Mem.Peek2(ip);
ip += 2;
match = op - offset;
Assert(match <= op); /* check overflow */
/* Do not deal with overlapping matches. */
if ((length != ML_MASK) &&
(offset >= 8) &&
(dict == dict_directive.withPrefix64k || match >= lowPrefix))
{
/* Copy the match. */
Mem.Copy18(op, match);
op += length + MINMATCH;
/* Both stages worked, load the next token. */
continue;
}
/* The second stage didn't work out, but the info is ready.
* Propel it right to the point of match copying. */
goto _copy_match;
}
/* decode literal length */
if (length == RUN_MASK)
{
variable_length_error error = variable_length_error.ok;
length += LZ4_readVLE(&ip, iend - RUN_MASK, endOnInput, endOnInput, &error);
if (error == variable_length_error.initial_error)
{
goto _output_error;
}
if ((safeDecode) && ((op) + length < (op)))
{
goto _output_error;
} /* overflow detection */
if ((safeDecode) && ((ip) + length < (ip)))
{
goto _output_error;
} /* overflow detection */
}
/* copy literals */
cpy = op + length;
if (((endOnInput) && ((cpy > oend - MFLIMIT) ||
(ip + length > iend - (2 + 1 + LASTLITERALS)))) ||
((!endOnInput) && (cpy > oend - WILDCOPYLENGTH)))
{
/* We've either hit the input parsing restriction or the output parsing restriction.
* If we've hit the input parsing condition then this must be the last sequence.
* If we've hit the output parsing condition then we are either using partialDecoding
* or we've hit the output parsing condition.
*/
if (partialDecoding)
{
/* Since we are partial decoding we may be in this block because of the output parsing
* restriction, which is not valid since the output buffer is allowed to be undersized.
*/
Assert(endOnInput);
/* If we're in this block because of the input parsing condition, then we must be on the
* last sequence (or invalid), so we must check that we exactly consume the input.
*/
if ((ip + length > iend - (2 + 1 + LASTLITERALS)) &&
(ip + length != iend))
{
goto _output_error;
}
Assert(ip + length <= iend);
/* We are finishing in the middle of a literals segment.
* Break after the copy.
*/
if (cpy > oend)
{
cpy = oend;
Assert(op <= oend);
length = (size_t)(oend - op);
}
Assert(ip + length <= iend);
}
else
{
/* We must be on the last sequence because of the parsing limitations so check
* that we exactly regenerate the original size (must be exact when !endOnInput).
*/
if ((!endOnInput) && (cpy != oend))
{
goto _output_error;
}
/* We must be on the last sequence (or invalid) because of the parsing limitations
* so check that we exactly consume the input and don't overrun the output buffer.
*/
if ((endOnInput) && ((ip + length != iend) || (cpy > oend)))
{
goto _output_error;
}
}
Mem.Move(op, ip, (int)length); /* supports overlapping memory regions, which only matters for in-place decompression scenarios */
ip += length;
op += length;
/* Necessarily EOF when !partialDecoding. When partialDecoding
* it is EOF if we've either filled the output buffer or hit
* the input parsing restriction.
*/
if (!partialDecoding || (cpy == oend) || (ip == iend))
{
break;
}
}
else
{
Mem.WildCopy8(
op, ip, cpy); /* may overwrite up to WILDCOPYLENGTH beyond cpy */
ip += length;
op = cpy;
}
/* get offset */
offset = Mem.Peek2(ip);
ip += 2;
match = op - offset;
/* get matchlength */
length = token & ML_MASK;
_copy_match:
if (length == ML_MASK)
{
variable_length_error error = variable_length_error.ok;
length += LZ4_readVLE(
&ip, iend - LASTLITERALS + 1, endOnInput, false, &error);
if (error != variable_length_error.ok)
{
goto _output_error;
}
if ((safeDecode) && ((op) + length < op))
{
goto _output_error; /* overflow detection */
}
}
length += MINMATCH;
if ((checkOffset) && ((match + dictSize < lowPrefix)))
{
goto _output_error; /* Error : offset outside buffers */
}
/* match starting within external dictionary */
if ((dict == dict_directive.usingExtDict) && (match < lowPrefix))
{
if ((op + length > oend - LASTLITERALS))
{
if (partialDecoding)
{
length = MIN(length, (size_t)(oend - op));
}
else
{
goto _output_error; /* doesn't respect parsing restriction */
}
}
if (length <= (size_t)(lowPrefix - match))
{
/* match fits entirely within external dictionary : just copy */
Mem.Move(op, dictEnd - (lowPrefix - match), (int)length);
op += length;
}
else
{
/* match stretches into both external dictionary and current block */
size_t copySize = (size_t)(lowPrefix - match);
size_t restSize = length - copySize;
Mem.Copy(op, dictEnd - copySize, (int)copySize);
op += copySize;
if (restSize > (size_t)(op - lowPrefix))
{
/* overlap copy */
byte *endOfMatch = op + restSize;
byte *copyFrom = lowPrefix;
while (op < endOfMatch)
{
*op++ = *copyFrom++;
}
}
else
{
Mem.Copy(op, lowPrefix, (int)restSize);
op += restSize;
}
}
continue;
}
Assert(match >= lowPrefix);
/* copy match within block */
cpy = op + length;
/* partialDecoding : may end anywhere within the block */
Assert(op <= oend);
if (partialDecoding && (cpy > oend - MATCH_SAFEGUARD_DISTANCE))
{
size_t mlen = MIN(length, (size_t)(oend - op));
byte * matchEnd = match + mlen;
byte * copyEnd = op + mlen;
if (matchEnd > op)
{
/* overlap copy */
while (op < copyEnd)
{
*op++ = *match++;
}
}
else
{
Mem.Copy(op, match, (int)mlen);
}
op = copyEnd;
if (op == oend)
{
break;
}
continue;
}
if ((offset < 8))
{
// Mem.Poke4(op, 0); /* silence msan warning when offset==0 */
op[0] = match[0];
op[1] = match[1];
op[2] = match[2];
op[3] = match[3];
match += inc32table[offset];
Mem.Copy4(op + 4, match);
match -= dec64table[offset];
}
else
{
Mem.Copy8(op, match);
match += 8;
}
op += 8;
if ((cpy > oend - MATCH_SAFEGUARD_DISTANCE))
{
byte *oCopyLimit = oend - (WILDCOPYLENGTH - 1);
if (cpy > oend - LASTLITERALS)
{
goto _output_error;
} /* Error : last LASTLITERALS bytes must be literals (uncompressed) */
if (op < oCopyLimit)
{
Mem.WildCopy8(op, match, oCopyLimit);
match += oCopyLimit - op;
op = oCopyLimit;
}
while (op < cpy)
{
*op++ = *match++;
}
}
else
{
Mem.Copy8(op, match);
if (length > 16)
{
Mem.WildCopy8(op + 8, match + 8, cpy);
}
}
op = cpy; /* wildcopy correction */
}
/* end of decoding */
if (endOnInput)
{
return((int)(((byte *)op) - dst)); /* Nb of output bytes decoded */
}
else
{
return((int)(((byte *)ip) - src)); /* Nb of input bytes read */
}
/* Overflow error detected */
_output_error:
return((int)(-(((byte *)ip) - src)) - 1);
}
}