Compress-LZ4
view release on metacpan or search on metacpan
}
length += MINMATCH;
/* check external dictionary */
if ((dict==usingExtDict) && (match < lowPrefix)) {
if (unlikely(op+length > oend-LASTLITERALS)) goto _output_error; /* doesn't respect parsing restriction */
if (length <= (size_t)(lowPrefix-match)) {
/* match can be copied as a single segment from external dictionary */
memmove(op, dictEnd - (lowPrefix-match), length);
op += length;
} else {
/* match encompass external dictionary and current block */
size_t const copySize = (size_t)(lowPrefix-match);
size_t const restSize = length - copySize;
memcpy(op, dictEnd - copySize, copySize);
op += copySize;
if (restSize > (size_t)(op-lowPrefix)) { /* overlap copy */
BYTE* const endOfMatch = op + restSize;
const BYTE* copyFrom = lowPrefix;
while (op < endOfMatch) *op++ = *copyFrom++;
} else {
memcpy(op, lowPrefix, restSize);
op += restSize;
} }
continue;
}
/* copy match within block */
cpy = op + length;
if (unlikely(offset<8)) {
const int dec64 = dec64table[offset];
op[0] = match[0];
op[1] = match[1];
op[2] = match[2];
op[3] = match[3];
match += dec32table[offset];
memcpy(op+4, match, 4);
match -= dec64;
} else { LZ4_copy8(op, match); match+=8; }
op += 8;
if (unlikely(cpy>oend-12)) {
BYTE* const oCopyLimit = oend-(WILDCOPYLENGTH-1);
if (cpy > oend-LASTLITERALS) goto _output_error; /* Error : last LASTLITERALS bytes must be literals (uncompressed) */
if (op < oCopyLimit) {
LZ4_wildCopy(op, match, oCopyLimit);
match += oCopyLimit - op;
op = oCopyLimit;
}
while (op<cpy) *op++ = *match++;
} else {
LZ4_copy8(op, match);
if (length>16) LZ4_wildCopy(op+8, match+8, cpy);
}
op=cpy; /* correction */
}
/* end of decoding */
if (endOnInput)
return (int) (((char*)op)-dest); /* Nb of output bytes decoded */
else
return (int) (((const char*)ip)-source); /* Nb of input bytes read */
/* Overflow error detected */
_output_error:
return (int) (-(((const char*)ip)-source))-1;
}
int LZ4_decompress_safe(const char* source, char* dest, int compressedSize, int maxDecompressedSize)
{
return LZ4_decompress_generic(source, dest, compressedSize, maxDecompressedSize, endOnInputSize, full, 0, noDict, (BYTE*)dest, NULL, 0);
}
int LZ4_decompress_safe_partial(const char* source, char* dest, int compressedSize, int targetOutputSize, int maxDecompressedSize)
{
return LZ4_decompress_generic(source, dest, compressedSize, maxDecompressedSize, endOnInputSize, partial, targetOutputSize, noDict, (BYTE*)dest, NULL, 0);
}
int LZ4_decompress_fast(const char* source, char* dest, int originalSize)
{
return LZ4_decompress_generic(source, dest, 0, originalSize, endOnOutputSize, full, 0, withPrefix64k, (BYTE*)(dest - 64 KB), NULL, 64 KB);
}
/*===== streaming decompression functions =====*/
/*
* If you prefer dynamic allocation methods,
* LZ4_createStreamDecode()
* provides a pointer (void*) towards an initialized LZ4_streamDecode_t structure.
*/
LZ4_streamDecode_t* LZ4_createStreamDecode(void)
{
LZ4_streamDecode_t* lz4s = (LZ4_streamDecode_t*) ALLOCATOR(1, sizeof(LZ4_streamDecode_t));
return lz4s;
}
int LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream)
{
FREEMEM(LZ4_stream);
return 0;
}
/*!
* LZ4_setStreamDecode() :
* Use this function to instruct where to find the dictionary.
* This function is not necessary if previous data is still available where it was decoded.
* Loading a size of 0 is allowed (same effect as no dictionary).
* Return : 1 if OK, 0 if error
*/
int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dictionary, int dictSize)
{
LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
lz4sd->prefixSize = (size_t) dictSize;
lz4sd->prefixEnd = (const BYTE*) dictionary + dictSize;
lz4sd->externalDict = NULL;
lz4sd->extDictSize = 0;
return 1;
}
/*
*_continue() :
These decoding functions allow decompression of multiple blocks in "streaming" mode.
Previously decoded blocks must still be available at the memory position where they were decoded.
If it's not possible, save the relevant part of decoded data into a safe buffer,
and indicate where it stands using LZ4_setStreamDecode()
*/
int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int compressedSize, int maxOutputSize)
{
LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
int result;
if (lz4sd->prefixEnd == (BYTE*)dest) {
result = LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize,
endOnInputSize, full, 0,
usingExtDict, lz4sd->prefixEnd - lz4sd->prefixSize, lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0) return result;
lz4sd->prefixSize += result;
lz4sd->prefixEnd += result;
} else {
lz4sd->extDictSize = lz4sd->prefixSize;
lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
result = LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize,
endOnInputSize, full, 0,
usingExtDict, (BYTE*)dest, lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0) return result;
lz4sd->prefixSize = result;
lz4sd->prefixEnd = (BYTE*)dest + result;
}
return result;
}
int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int originalSize)
{
LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
int result;
if (lz4sd->prefixEnd == (BYTE*)dest) {
result = LZ4_decompress_generic(source, dest, 0, originalSize,
endOnOutputSize, full, 0,
usingExtDict, lz4sd->prefixEnd - lz4sd->prefixSize, lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0) return result;
lz4sd->prefixSize += originalSize;
lz4sd->prefixEnd += originalSize;
} else {
lz4sd->extDictSize = lz4sd->prefixSize;
lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
result = LZ4_decompress_generic(source, dest, 0, originalSize,
endOnOutputSize, full, 0,
usingExtDict, (BYTE*)dest, lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0) return result;
lz4sd->prefixSize = originalSize;
lz4sd->prefixEnd = (BYTE*)dest + originalSize;
}
return result;
}
/*
Advanced decoding functions :
*_usingDict() :
These decoding functions work the same as "_continue" ones,
the dictionary must be explicitly provided within parameters
( run in 0.779 second using v1.01-cache-2.11-cpan-7fcb06a456a )