Compress-LZ4Frame
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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)-dst); /* Nb of output bytes decoded */
else
return (int) (((const char*)ip)-src); /* Nb of input bytes read */
/* Overflow error detected */
_output_error:
return (int) (-(((const char*)ip)-src))-1;
}
LZ4_FORCE_O2_GCC_PPC64LE
int LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream)
{
if (!LZ4_stream) return 0; /* support free on NULL */
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()
*/
LZ4_FORCE_O2_GCC_PPC64LE
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,
Use this function in trusted environment only (data to decode comes from a trusted source).
*/
LZ4LIB_API int LZ4_decompress_fast (const char* src, char* dst, int originalSize);
/*!
LZ4_decompress_safe_partial() :
This function decompress a compressed block of size 'srcSize' at position 'src'
into destination buffer 'dst' of size 'dstCapacity'.
The function will decompress a minimum of 'targetOutputSize' bytes, and stop after that.
However, it's not accurate, and may write more than 'targetOutputSize' (but <= dstCapacity).
@return : the number of bytes decoded in the destination buffer (necessarily <= dstCapacity)
Note : this number can be < 'targetOutputSize' should the compressed block contain less data.
Always control how many bytes were decoded.
If the source stream is detected malformed, the function will stop decoding and return a negative result.
This function never writes outside of output buffer, and never reads outside of input buffer. It is therefore protected against malicious data packets.
*/
LZ4LIB_API int LZ4_decompress_safe_partial (const char* src, char* dst, int srcSize, int targetOutputSize, int dstCapacity);
/*-*********************************************
* Streaming Compression Functions
***********************************************/
typedef union LZ4_stream_u LZ4_stream_t; /* incomplete type (defined later) */
* Use this function to start decompression of a new stream of blocks.
* A dictionary can optionnally be set. Use NULL or size 0 for a simple reset order.
* @return : 1 if OK, 0 if error
*/
LZ4LIB_API int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dictionary, int dictSize);
/*! LZ4_decompress_*_continue() :
* These decoding functions allow decompression of consecutive blocks in "streaming" mode.
* A block is an unsplittable entity, it must be presented entirely to a decompression function.
* Decompression functions only accept one block at a time.
* Previously decoded blocks *must* remain available at the memory position where they were decoded (up to 64 KB).
*
* Special : if application sets a ring buffer for decompression, it must respect one of the following conditions :
* - Exactly same size as encoding buffer, with same update rule (block boundaries at same positions)
* In which case, the decoding & encoding ring buffer can have any size, including very small ones ( < 64 KB).
* - Larger than encoding buffer, by a minimum of maxBlockSize more bytes.
* maxBlockSize is implementation dependent. It's the maximum size of any single block.
* In which case, encoding and decoding buffers do not need to be synchronized,
* and encoding ring buffer can have any size, including small ones ( < 64 KB).
* - _At least_ 64 KB + 8 bytes + maxBlockSize.
* In which case, encoding and decoding buffers do not need to be synchronized,
* and encoding ring buffer can have any size, including larger than decoding buffer.
* Whenever these conditions are not possible, save the last 64KB of decoded data into a safe buffer,
* and indicate where it is saved using LZ4_setStreamDecode() before decompressing next block.
*/
LZ4LIB_API int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* src, char* dst, int srcSize, int dstCapacity);
LZ4LIB_API int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* src, char* dst, int originalSize);
/*! LZ4_decompress_*_usingDict() :
* These decoding functions work the same as
* a combination of LZ4_setStreamDecode() followed by LZ4_decompress_*_continue()
* They are stand-alone, and don't need an LZ4_streamDecode_t structure.
* Decompression must resume from (srcBuffer + *srcSizePtr).
* @return : an hint about how many srcSize bytes LZ4F_decompress() expects for next call,
* or an error code which can be tested using LZ4F_isError()
* note 1 : in case of error, dctx is not modified. Decoding operations can resume from where they stopped.
* note 2 : frame parameters are *copied into* an already allocated LZ4F_frameInfo_t structure.
*/
LZ4F_errorCode_t LZ4F_getFrameInfo(LZ4F_dctx* dctx, LZ4F_frameInfo_t* frameInfoPtr,
const void* srcBuffer, size_t* srcSizePtr)
{
if (dctx->dStage > dstage_storeFrameHeader) { /* assumption : dstage_* header enum at beginning of range */
/* frameInfo already decoded */
size_t o=0, i=0;
*srcSizePtr = 0;
*frameInfoPtr = dctx->frameInfo;
/* returns : recommended nb of bytes for LZ4F_decompress() */
return LZ4F_decompress(dctx, NULL, &o, NULL, &i, NULL);
} else {
if (dctx->dStage == dstage_storeFrameHeader) {
/* frame decoding already started, in the middle of header => automatic fail */
*srcSizePtr = 0;
return err0r(LZ4F_ERROR_frameDecoding_alreadyStarted);
* The number of bytes regenerated into dstBuffer will be provided within *dstSizePtr (necessarily <= original value).
*
* The number of bytes effectively read from srcBuffer will be provided within *srcSizePtr (necessarily <= original value).
* If number of bytes read is < number of bytes provided, then decompression operation is not complete.
* Remaining data will have to be presented again in a subsequent invocation.
*
* The function result is an hint of the better srcSize to use for next call to LZ4F_decompress.
* Schematically, it's the size of the current (or remaining) compressed block + header of next block.
* Respecting the hint provides a small boost to performance, since it allows less buffer shuffling.
* Note that this is just a hint, and it's always possible to any srcSize value.
* When a frame is fully decoded, @return will be 0.
* If decompression failed, @return is an error code which can be tested using LZ4F_isError().
*/
size_t LZ4F_decompress(LZ4F_dctx* dctx,
void* dstBuffer, size_t* dstSizePtr,
const void* srcBuffer, size_t* srcSizePtr,
const LZ4F_decompressOptions_t* decompressOptionsPtr)
{
LZ4F_decompressOptions_t optionsNull;
const BYTE* const srcStart = (const BYTE*)srcBuffer;
const BYTE* const srcEnd = srcStart + *srcSizePtr;
dctx->tmpInTarget -= 4;
assert(selectedIn != NULL); /* selectedIn is defined at this stage (either srcPtr, or dctx->tmpIn) */
{ U32 const readBlockCrc = LZ4F_readLE32(selectedIn + dctx->tmpInTarget);
U32 const calcBlockCrc = XXH32(selectedIn, dctx->tmpInTarget, 0);
if (readBlockCrc != calcBlockCrc)
return err0r(LZ4F_ERROR_blockChecksum_invalid);
} }
if ((size_t)(dstEnd-dstPtr) >= dctx->maxBlockSize) {
/* enough capacity in `dst` to decompress directly there */
int const decodedSize = LZ4_decompress_safe_usingDict(
(const char*)selectedIn, (char*)dstPtr,
(int)dctx->tmpInTarget, (int)dctx->maxBlockSize,
(const char*)dctx->dict, (int)dctx->dictSize);
if (decodedSize < 0) return err0r(LZ4F_ERROR_GENERIC); /* decompression failed */
if (dctx->frameInfo.contentChecksumFlag)
XXH32_update(&(dctx->xxh), dstPtr, decodedSize);
if (dctx->frameInfo.contentSize)
dctx->frameRemainingSize -= decodedSize;
/* dictionary management */
if (dctx->frameInfo.blockMode==LZ4F_blockLinked)
LZ4F_updateDict(dctx, dstPtr, decodedSize, dstStart, 0);
dstPtr += decodedSize;
dctx->dStage = dstage_getBlockHeader;
break;
}
/* not enough place into dst : decode into tmpOut */
/* ensure enough place for tmpOut */
if (dctx->frameInfo.blockMode == LZ4F_blockLinked) {
if (dctx->dict == dctx->tmpOutBuffer) {
if (dctx->dictSize > 128 KB) {
memcpy(dctx->tmpOutBuffer, dctx->dict + dctx->dictSize - 64 KB, 64 KB);
dctx->dictSize = 64 KB;
}
dctx->tmpOut = dctx->tmpOutBuffer + dctx->dictSize;
} else { /* dict not within tmp */
size_t const reservedDictSpace = MIN(dctx->dictSize, 64 KB);
dctx->tmpOut = dctx->tmpOutBuffer + reservedDictSpace;
}
}
/* Decode block */
{ int const decodedSize = LZ4_decompress_safe_usingDict(
(const char*)selectedIn, (char*)dctx->tmpOut,
(int)dctx->tmpInTarget, (int)dctx->maxBlockSize,
(const char*)dctx->dict, (int)dctx->dictSize);
if (decodedSize < 0) /* decompression failed */
return err0r(LZ4F_ERROR_decompressionFailed);
if (dctx->frameInfo.contentChecksumFlag)
XXH32_update(&(dctx->xxh), dctx->tmpOut, decodedSize);
if (dctx->frameInfo.contentSize)
dctx->frameRemainingSize -= decodedSize;
dctx->tmpOutSize = decodedSize;
dctx->tmpOutStart = 0;
dctx->dStage = dstage_flushOut;
}
/* fall-through */
case dstage_flushOut: /* flush decoded data from tmpOut to dstBuffer */
{ size_t const sizeToCopy = MIN(dctx->tmpOutSize - dctx->tmpOutStart, (size_t)(dstEnd-dstPtr));
memcpy(dstPtr, dctx->tmpOut + dctx->tmpOutStart, sizeToCopy);
/* dictionary management */
if (dctx->frameInfo.blockMode==LZ4F_blockLinked)
LZ4F_updateDict(dctx, dstPtr, sizeToCopy, dstStart, 1);
dctx->tmpOutStart += sizeToCopy;
dstPtr += sizeToCopy;
dctx->dStage = dstage_getBlockHeader; /* get next block */
break;
}
nextSrcSizeHint = BHSize;
doAnotherStage = 0; /* still some data to flush */
break;
}
case dstage_getSuffix:
if (dctx->frameRemainingSize)
return err0r(LZ4F_ERROR_frameSize_wrong); /* incorrect frame size decoded */
if (!dctx->frameInfo.contentChecksumFlag) { /* no checksum, frame is completed */
nextSrcSizeHint = 0;
LZ4F_resetDecompressionContext(dctx);
doAnotherStage = 0;
break;
}
if ((srcEnd - srcPtr) < 4) { /* not enough size for entire CRC */
dctx->tmpInSize = 0;
dctx->dStage = dstage_storeSuffix;
} else {
LZ4FLIB_API size_t LZ4F_compressEnd(LZ4F_cctx* cctx, void* dstBuffer, size_t dstCapacity, const LZ4F_compressOptions_t* cOptPtr);
/*-*********************************
* Decompression functions
***********************************/
typedef struct LZ4F_dctx_s LZ4F_dctx; /* incomplete type */
typedef LZ4F_dctx* LZ4F_decompressionContext_t; /* compatibility with previous API versions */
typedef struct {
unsigned stableDst; /* pledge that at least 64KB+64Bytes of previously decompressed data remain unmodifed where it was decoded. This optimization skips storage operations in tmp buffers */
unsigned reserved[3]; /* must be set to zero for forward compatibility */
} LZ4F_decompressOptions_t;
/* Resource management */
/*! LZ4F_createDecompressionContext() :
* Create an LZ4F_dctx object, to track all decompression operations.
* The version provided MUST be LZ4F_VERSION.
* The function provides a pointer to an allocated and initialized LZ4F_dctx object.
* Unconsumed source data must be presented again in subsequent invocations.
*
* `dstBuffer` can freely change between each consecutive function invocation.
* `dstBuffer` content will be overwritten.
*
* @return : an hint of how many `srcSize` bytes LZ4F_decompress() expects for next call.
* Schematically, it's the size of the current (or remaining) compressed block + header of next block.
* Respecting the hint provides some small speed benefit, because it skips intermediate buffers.
* This is just a hint though, it's always possible to provide any srcSize.
*
* When a frame is fully decoded, @return will be 0 (no more data expected).
* When provided with more bytes than necessary to decode a frame,
* LZ4F_decompress() will stop reading exactly at end of current frame, and @return 0.
*
* If decompression failed, @return is an error code, which can be tested using LZ4F_isError().
* After a decompression error, the `dctx` context is not resumable.
* Use LZ4F_resetDecompressionContext() to return to clean state.
*
* After a frame is fully decoded, dctx can be used again to decompress another frame.
*/
LZ4FLIB_API size_t LZ4F_decompress(LZ4F_dctx* dctx,
void* dstBuffer, size_t* dstSizePtr,
const void* srcBuffer, size_t* srcSizePtr,
const LZ4F_decompressOptions_t* dOptPtr);
/*! LZ4F_resetDecompressionContext() : added in v1.8.0
* In case of an error, the context is left in "undefined" state.
* In which case, it's necessary to reset it, before re-using it.
( run in 0.329 second using v1.01-cache-2.11-cpan-a9ef4e587e4 )