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fix #198 : no longer requires to restart streaming decompression from where it stopped.

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It permits relocating remaining data into another memory space.
Still, the same content must be presented.
This commit is contained in:
Yann Collet 2016-11-03 18:34:54 -07:00
parent 4791cda04a
commit eda8c4eb1c
3 changed files with 110 additions and 134 deletions
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216
lib/lz4frame.c
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@ -171,28 +171,6 @@ typedef struct LZ4F_cctx_s
U32 lz4CtxLevel; /* 0: unallocated; 1: LZ4_stream_t; 3: LZ4_streamHC_t */
} LZ4F_cctx_t;
typedef struct LZ4F_dctx_s
{
LZ4F_frameInfo_t frameInfo;
U32 version;
U32 dStage;
U64 frameRemainingSize;
size_t maxBlockSize;
size_t maxBufferSize;
const BYTE* srcExpect;
BYTE* tmpIn;
size_t tmpInSize;
size_t tmpInTarget;
BYTE* tmpOutBuffer;
const BYTE* dict;
size_t dictSize;
BYTE* tmpOut;
size_t tmpOutSize;
size_t tmpOutStart;
XXH32_state_t xxh;
BYTE header[16];
} LZ4F_dctx_t;
/*-************************************
* Error management
@ -232,7 +210,7 @@ static size_t LZ4F_getBlockSize(unsigned blockSizeID)
static BYTE LZ4F_headerChecksum (const void* header, size_t length)
{
U32 xxh = XXH32(header, length, 0);
U32 const xxh = XXH32(header, length, 0);
return (BYTE)(xxh >> 8);
}
@ -283,16 +261,15 @@ size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* prefere
* The result of the function is the number of bytes written into dstBuffer.
* The function outputs an error code if it fails (can be tested using LZ4F_isError())
*/
size_t LZ4F_compressFrame(void* dstBuffer, size_t dstMaxSize, const void* srcBuffer, size_t srcSize, const LZ4F_preferences_t* preferencesPtr)
size_t LZ4F_compressFrame(void* dstBuffer, size_t dstCapacity, const void* srcBuffer, size_t srcSize, const LZ4F_preferences_t* preferencesPtr)
{
LZ4F_cctx_t cctxI;
LZ4_stream_t lz4ctx;
LZ4F_preferences_t prefs;
LZ4F_compressOptions_t options;
LZ4F_errorCode_t errorCode;
BYTE* const dstStart = (BYTE*) dstBuffer;
BYTE* dstPtr = dstStart;
BYTE* const dstEnd = dstStart + dstMaxSize;
BYTE* const dstEnd = dstStart + dstCapacity;
memset(&cctxI, 0, sizeof(cctxI)); /* works because no allocation */
memset(&options, 0, sizeof(options));
@ -319,22 +296,22 @@ size_t LZ4F_compressFrame(void* dstBuffer, size_t dstMaxSize, const void* srcBuf
options.stableSrc = 1;
if (dstMaxSize < LZ4F_compressFrameBound(srcSize, &prefs))
if (dstCapacity < LZ4F_compressFrameBound(srcSize, &prefs))
return (size_t)-LZ4F_ERROR_dstMaxSize_tooSmall;
errorCode = LZ4F_compressBegin(&cctxI, dstBuffer, dstMaxSize, &prefs); /* write header */
if (LZ4F_isError(errorCode)) return errorCode;
dstPtr += errorCode; /* header size */
{ size_t const headerSize = LZ4F_compressBegin(&cctxI, dstBuffer, dstCapacity, &prefs); /* write header */
if (LZ4F_isError(headerSize)) return headerSize;
dstPtr += headerSize; /* header size */ }
errorCode = LZ4F_compressUpdate(&cctxI, dstPtr, dstEnd-dstPtr, srcBuffer, srcSize, &options);
if (LZ4F_isError(errorCode)) return errorCode;
dstPtr += errorCode;
{ size_t const cSize = LZ4F_compressUpdate(&cctxI, dstPtr, dstEnd-dstPtr, srcBuffer, srcSize, &options);
if (LZ4F_isError(cSize)) return cSize;
dstPtr += cSize; }
errorCode = LZ4F_compressEnd(&cctxI, dstPtr, dstEnd-dstPtr, &options); /* flush last block, and generate suffix */
if (LZ4F_isError(errorCode)) return errorCode;
dstPtr += errorCode;
{ size_t const tailSize = LZ4F_compressEnd(&cctxI, dstPtr, dstEnd-dstPtr, &options); /* flush last block, and generate suffix */
if (LZ4F_isError(tailSize)) return tailSize;
dstPtr += tailSize; }
if (prefs.compressionLevel >= LZ4HC_MIN_CLEVEL) /* no allocation necessary with lz4 fast */
if (prefs.compressionLevel >= LZ4HC_MIN_CLEVEL) /* no allocation done with lz4 fast */
FREEMEM(cctxI.lz4CtxPtr);
return (dstPtr - dstStart);
@ -345,19 +322,17 @@ size_t LZ4F_compressFrame(void* dstBuffer, size_t dstMaxSize, const void* srcBuf
* Advanced compression functions
***********************************/
/* LZ4F_createCompressionContext() :
* The first thing to do is to create a compressionContext object, which will be used in all compression operations.
* This is achieved using LZ4F_createCompressionContext(), which takes as argument a version and an LZ4F_preferences_t structure.
* The version provided MUST be LZ4F_VERSION. It is intended to track potential version differences between different binaries.
* The function will provide a pointer to an allocated LZ4F_compressionContext_t object.
* If the result LZ4F_errorCode_t is not OK_NoError, there was an error during context creation.
* Object can release its memory using LZ4F_freeCompressionContext();
*/
/*! LZ4F_createCompressionContext() :
* The first thing to do is to create a compressionContext object, which will be used in all compression operations.
* This is achieved using LZ4F_createCompressionContext(), which takes as argument a version and an LZ4F_preferences_t structure.
* The version provided MUST be LZ4F_VERSION. It is intended to track potential version differences between different binaries.
* The function will provide a pointer to an allocated LZ4F_compressionContext_t object.
* If the result LZ4F_errorCode_t is not OK_NoError, there was an error during context creation.
* Object can release its memory using LZ4F_freeCompressionContext();
*/
LZ4F_errorCode_t LZ4F_createCompressionContext(LZ4F_compressionContext_t* LZ4F_compressionContextPtr, unsigned version)
{
LZ4F_cctx_t* cctxPtr;
cctxPtr = (LZ4F_cctx_t*)ALLOCATOR(sizeof(LZ4F_cctx_t));
LZ4F_cctx_t* const cctxPtr = (LZ4F_cctx_t*)ALLOCATOR(sizeof(LZ4F_cctx_t));
if (cctxPtr==NULL) return (LZ4F_errorCode_t)(-LZ4F_ERROR_allocation_failed);
cctxPtr->version = version;
@ -371,7 +346,7 @@ LZ4F_errorCode_t LZ4F_createCompressionContext(LZ4F_compressionContext_t* LZ4F_c
LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_compressionContext_t LZ4F_compressionContext)
{
LZ4F_cctx_t* cctxPtr = (LZ4F_cctx_t*)LZ4F_compressionContext;
LZ4F_cctx_t* const cctxPtr = (LZ4F_cctx_t*)LZ4F_compressionContext;
if (cctxPtr != NULL) { /* null pointers can be safely provided to this function, like free() */
FREEMEM(cctxPtr->lz4CtxPtr);
@ -384,15 +359,14 @@ LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_compressionContext_t LZ4F_comp
/*! LZ4F_compressBegin() :
* will write the frame header into dstBuffer.
* dstBuffer must be large enough to accommodate a header (dstMaxSize). Maximum header size is LZ4F_MAXHEADERFRAME_SIZE bytes.
* The result of the function is the number of bytes written into dstBuffer for the header
* or an error code (can be tested using LZ4F_isError())
*/
size_t LZ4F_compressBegin(LZ4F_compressionContext_t compressionContext, void* dstBuffer, size_t dstMaxSize, const LZ4F_preferences_t* preferencesPtr)
* will write the frame header into dstBuffer.
* dstBuffer must be large enough to accommodate a header (dstMaxSize). Maximum header size is LZ4F_MAXHEADERFRAME_SIZE bytes.
* @return : number of bytes written into dstBuffer for the header
* or an error code (can be tested using LZ4F_isError())
*/
size_t LZ4F_compressBegin(LZ4F_cctx* cctxPtr, void* dstBuffer, size_t dstMaxSize, const LZ4F_preferences_t* preferencesPtr)
{
LZ4F_preferences_t prefNull;
LZ4F_cctx_t* cctxPtr = (LZ4F_cctx_t*)compressionContext;
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* dstPtr = dstStart;
BYTE* headerStart;
@ -475,13 +449,13 @@ size_t LZ4F_compressBound(size_t srcSize, const LZ4F_preferences_t* preferencesP
LZ4F_preferences_t prefsNull;
memset(&prefsNull, 0, sizeof(prefsNull));
prefsNull.frameInfo.contentChecksumFlag = LZ4F_contentChecksumEnabled; /* worst case */
{ const LZ4F_preferences_t* prefsPtr = (preferencesPtr==NULL) ? &prefsNull : preferencesPtr;
LZ4F_blockSizeID_t bid = prefsPtr->frameInfo.blockSizeID;
size_t blockSize = LZ4F_getBlockSize(bid);
unsigned nbBlocks = (unsigned)(srcSize / blockSize) + 1;
size_t lastBlockSize = prefsPtr->autoFlush ? srcSize % blockSize : blockSize;
size_t blockInfo = 4; /* default, without block CRC option */
size_t frameEnd = 4 + (prefsPtr->frameInfo.contentChecksumFlag*4);
{ const LZ4F_preferences_t* const prefsPtr = (preferencesPtr==NULL) ? &prefsNull : preferencesPtr;
LZ4F_blockSizeID_t const bid = prefsPtr->frameInfo.blockSizeID;
size_t const blockSize = LZ4F_getBlockSize(bid);
unsigned const nbBlocks = (unsigned)(srcSize / blockSize) + 1;
size_t const lastBlockSize = prefsPtr->autoFlush ? srcSize % blockSize : blockSize;
size_t const blockInfo = 4; /* default, without block CRC option */
size_t const frameEnd = 4 + (prefsPtr->frameInfo.contentChecksumFlag*4);
return (blockInfo * nbBlocks) + (blockSize * (nbBlocks-1)) + lastBlockSize + frameEnd;;
}
@ -493,9 +467,8 @@ typedef int (*compressFunc_t)(void* ctx, const char* src, char* dst, int srcSize
static size_t LZ4F_compressBlock(void* dst, const void* src, size_t srcSize, compressFunc_t compress, void* lz4ctx, int level)
{
/* compress one block */
BYTE* cSizePtr = (BYTE*)dst;
U32 cSize;
cSize = (U32)compress(lz4ctx, (const char*)src, (char*)(cSizePtr+4), (int)(srcSize), (int)(srcSize-1), level);
BYTE* const cSizePtr = (BYTE*)dst;
U32 cSize = (U32)compress(lz4ctx, (const char*)src, (char*)(cSizePtr+4), (int)(srcSize), (int)(srcSize-1), level);
LZ4F_writeLE32(cSizePtr, cSize);
if (cSize == 0) { /* compression failed */
cSize = (U32)srcSize;
@ -552,11 +525,10 @@ typedef enum { notDone, fromTmpBuffer, fromSrcBuffer } LZ4F_lastBlockStatus;
* The result of the function is the number of bytes written into dstBuffer : it can be zero, meaning input data was just buffered.
* The function outputs an error code if it fails (can be tested using LZ4F_isError())
*/
size_t LZ4F_compressUpdate(LZ4F_compressionContext_t compressionContext, void* dstBuffer, size_t dstMaxSize, const void* srcBuffer, size_t srcSize, const LZ4F_compressOptions_t* compressOptionsPtr)
size_t LZ4F_compressUpdate(LZ4F_cctx* cctxPtr, void* dstBuffer, size_t dstMaxSize, const void* srcBuffer, size_t srcSize, const LZ4F_compressOptions_t* compressOptionsPtr)
{
LZ4F_compressOptions_t cOptionsNull;
LZ4F_cctx_t* cctxPtr = (LZ4F_cctx_t*)compressionContext;
size_t blockSize = cctxPtr->maxBlockSize;
size_t const blockSize = cctxPtr->maxBlockSize;
const BYTE* srcPtr = (const BYTE*)srcBuffer;
const BYTE* const srcEnd = srcPtr + srcSize;
BYTE* const dstStart = (BYTE*)dstBuffer;
@ -575,7 +547,7 @@ size_t LZ4F_compressUpdate(LZ4F_compressionContext_t compressionContext, void* d
/* complete tmp buffer */
if (cctxPtr->tmpInSize > 0) { /* some data already within tmp buffer */
size_t sizeToCopy = blockSize - cctxPtr->tmpInSize;
size_t const sizeToCopy = blockSize - cctxPtr->tmpInSize;
if (sizeToCopy > srcSize) {
/* add src to tmpIn buffer */
memcpy(cctxPtr->tmpIn + cctxPtr->tmpInSize, srcBuffer, srcSize);
@ -631,7 +603,7 @@ size_t LZ4F_compressUpdate(LZ4F_compressionContext_t compressionContext, void* d
/* some input data left, necessarily < blockSize */
if (srcPtr < srcEnd) {
/* fill tmp buffer */
size_t sizeToCopy = srcEnd - srcPtr;
size_t const sizeToCopy = srcEnd - srcPtr;
memcpy(cctxPtr->tmpIn, srcPtr, sizeToCopy);
cctxPtr->tmpInSize = sizeToCopy;
}
@ -652,14 +624,12 @@ size_t LZ4F_compressUpdate(LZ4F_compressionContext_t compressionContext, void* d
* The function outputs an error code if it fails (can be tested using LZ4F_isError())
* The LZ4F_compressOptions_t structure is optional : you can provide NULL as argument.
*/
size_t LZ4F_flush(LZ4F_compressionContext_t compressionContext, void* dstBuffer, size_t dstMaxSize, const LZ4F_compressOptions_t* compressOptionsPtr)
size_t LZ4F_flush(LZ4F_cctx* cctxPtr, void* dstBuffer, size_t dstMaxSize, const LZ4F_compressOptions_t* compressOptionsPtr)
{
LZ4F_cctx_t* cctxPtr = (LZ4F_cctx_t*)compressionContext;
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* dstPtr = dstStart;
compressFunc_t compress;
if (cctxPtr->tmpInSize == 0) return 0; /* nothing to flush */
if (cctxPtr->cStage != 1) return (size_t)-LZ4F_ERROR_GENERIC;
if (dstMaxSize < (cctxPtr->tmpInSize + 8)) return (size_t)-LZ4F_ERROR_dstMaxSize_tooSmall; /* +8 : block header(4) + block checksum(4) */
@ -692,22 +662,20 @@ size_t LZ4F_flush(LZ4F_compressionContext_t compressionContext, void* dstBuffer,
* The LZ4F_compressOptions_t structure is optional : you can provide NULL as argument.
* compressionContext can then be used again, starting with LZ4F_compressBegin(). The preferences will remain the same.
*/
size_t LZ4F_compressEnd(LZ4F_compressionContext_t compressionContext, void* dstBuffer, size_t dstMaxSize, const LZ4F_compressOptions_t* compressOptionsPtr)
size_t LZ4F_compressEnd(LZ4F_cctx* cctxPtr, void* dstBuffer, size_t dstMaxSize, const LZ4F_compressOptions_t* compressOptionsPtr)
{
LZ4F_cctx_t* cctxPtr = (LZ4F_cctx_t*)compressionContext;
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* dstPtr = dstStart;
size_t errorCode;
errorCode = LZ4F_flush(compressionContext, dstBuffer, dstMaxSize, compressOptionsPtr);
if (LZ4F_isError(errorCode)) return errorCode;
dstPtr += errorCode;
size_t const flushSize = LZ4F_flush(cctxPtr, dstBuffer, dstMaxSize, compressOptionsPtr);
if (LZ4F_isError(flushSize)) return flushSize;
dstPtr += flushSize;
LZ4F_writeLE32(dstPtr, 0);
dstPtr+=4; /* endMark */
if (cctxPtr->prefs.frameInfo.contentChecksumFlag == LZ4F_contentChecksumEnabled) {
U32 xxh = XXH32_digest(&(cctxPtr->xxh));
U32 const xxh = XXH32_digest(&(cctxPtr->xxh));
LZ4F_writeLE32(dstPtr, xxh);
dstPtr+=4; /* content Checksum */
}
@ -728,7 +696,26 @@ size_t LZ4F_compressEnd(LZ4F_compressionContext_t compressionContext, void* dstB
* Frame Decompression
*****************************************************/
/* Resource management */
struct LZ4F_dctx_s {
LZ4F_frameInfo_t frameInfo;
U32 version;
U32 dStage;
U64 frameRemainingSize;
size_t maxBlockSize;
size_t maxBufferSize;
BYTE* tmpIn;
size_t tmpInSize;
size_t tmpInTarget;
BYTE* tmpOutBuffer;
const BYTE* dict;
size_t dictSize;
BYTE* tmpOut;
size_t tmpOutSize;
size_t tmpOutStart;
XXH32_state_t xxh;
BYTE header[16];
}; /* typedef'd to LZ4F_dctx in lz4frame.h */
/*! LZ4F_createDecompressionContext() :
* Create a decompressionContext object, which will track all decompression operations.
@ -736,20 +723,19 @@ size_t LZ4F_compressEnd(LZ4F_compressionContext_t compressionContext, void* dstB
* Object can later be released using LZ4F_freeDecompressionContext().
* @return : if != 0, there was an error during context creation.
*/
LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_decompressionContext_t* LZ4F_decompressionContextPtr, unsigned versionNumber)
LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_dctx** LZ4F_decompressionContextPtr, unsigned versionNumber)
{
LZ4F_dctx_t* const dctxPtr = (LZ4F_dctx_t*)ALLOCATOR(sizeof(LZ4F_dctx_t));
LZ4F_dctx* const dctxPtr = (LZ4F_dctx*)ALLOCATOR(sizeof(LZ4F_dctx));
if (dctxPtr==NULL) return (LZ4F_errorCode_t)-LZ4F_ERROR_GENERIC;
dctxPtr->version = versionNumber;
*LZ4F_decompressionContextPtr = (LZ4F_decompressionContext_t)dctxPtr;
*LZ4F_decompressionContextPtr = dctxPtr;
return LZ4F_OK_NoError;
}
LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_decompressionContext_t LZ4F_decompressionContext)
LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* const dctxPtr)
{
LZ4F_errorCode_t result = LZ4F_OK_NoError;
LZ4F_dctx_t* const dctxPtr = (LZ4F_dctx_t*)LZ4F_decompressionContext;
if (dctxPtr != NULL) { /* can accept NULL input, like free() */
result = (LZ4F_errorCode_t)dctxPtr->dStage;
FREEMEM(dctxPtr->tmpIn);
@ -760,9 +746,7 @@ LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_decompressionContext_t LZ4F_
}
/* ******************************************************************** */
/* ********************* Decompression ******************************** */
/* ******************************************************************** */
/*==--- Streaming Decompression operations ---==*/
typedef enum { dstage_getHeader=0, dstage_storeHeader,
dstage_getCBlockSize, dstage_storeCBlockSize,
@ -800,20 +784,20 @@ static size_t LZ4F_headerSize(const void* src, size_t srcSize)
/*! LZ4F_decodeHeader() :
input : `srcVoidPtr` points at the **beginning of the frame**
input : `src` points at the **beginning of the frame**
output : set internal values of dctx, such as
dctxPtr->frameInfo and dctxPtr->dStage.
Also allocates internal buffers.
@return : nb Bytes read from srcVoidPtr (necessarily <= srcSize)
or an error code (testable with LZ4F_isError())
*/
static size_t LZ4F_decodeHeader(LZ4F_dctx_t* dctxPtr, const void* srcVoidPtr, size_t srcSize)
static size_t LZ4F_decodeHeader(LZ4F_dctx* dctxPtr, const void* src, size_t srcSize)
{
BYTE FLG, BD, HC;
unsigned version, blockMode, blockChecksumFlag, contentSizeFlag, contentChecksumFlag, blockSizeID;
size_t bufferNeeded;
size_t frameHeaderSize;
const BYTE* srcPtr = (const BYTE*)srcVoidPtr;
const BYTE* srcPtr = (const BYTE*)src;
/* need to decode header to get frameInfo */
if (srcSize < minFHSize) return (size_t)-LZ4F_ERROR_frameHeader_incomplete; /* minimal frame header size */
@ -822,7 +806,7 @@ static size_t LZ4F_decodeHeader(LZ4F_dctx_t* dctxPtr, const void* srcVoidPtr, si
/* special case : skippable frames */
if ((LZ4F_readLE32(srcPtr) & 0xFFFFFFF0U) == LZ4F_MAGIC_SKIPPABLE_START) {
dctxPtr->frameInfo.frameType = LZ4F_skippableFrame;
if (srcVoidPtr == (void*)(dctxPtr->header)) {
if (src == (void*)(dctxPtr->header)) {
dctxPtr->tmpInSize = srcSize;
dctxPtr->tmpInTarget = 8;
dctxPtr->dStage = dstage_storeSFrameSize;
@ -910,26 +894,23 @@ static size_t LZ4F_decodeHeader(LZ4F_dctx_t* dctxPtr, const void* srcVoidPtr, si
/*! LZ4F_getFrameInfo() :
* Decodes frame header information, such as blockSize.
* It is optional : you could start by calling directly LZ4F_decompress() instead.
* Decodes frame header information, such as blockSize. Usage is optional.
* The objective is to extract header information without starting decompression, typically for allocation purposes.
* LZ4F_getFrameInfo() can also be used *after* starting decompression, on a valid LZ4F_decompressionContext_t.
* The number of bytes read from srcBuffer will be provided within *srcSizePtr (necessarily <= original value).
* You are expected to resume decompression from where it stopped (srcBuffer + *srcSizePtr)
* The number of bytes consumed from srcBuffer will be provided within *srcSizePtr (necessarily <= original value).
* Decompression must resume from where it stopped (srcBuffer + *srcSizePtr)
* @return : hint of the better `srcSize` to use for next call to LZ4F_decompress,
* or an error code which can be tested using LZ4F_isError().
*/
LZ4F_errorCode_t LZ4F_getFrameInfo(LZ4F_decompressionContext_t dCtx, LZ4F_frameInfo_t* frameInfoPtr,
LZ4F_errorCode_t LZ4F_getFrameInfo(LZ4F_dctx* dctxPtr, LZ4F_frameInfo_t* frameInfoPtr,
const void* srcBuffer, size_t* srcSizePtr)
{
LZ4F_dctx_t* dctxPtr = (LZ4F_dctx_t*)dCtx;
if (dctxPtr->dStage > dstage_storeHeader) { /* note : requires dstage_* header related to be at beginning of enum */
/* frameInfo already decoded */
size_t o=0, i=0;
*srcSizePtr = 0;
*frameInfoPtr = dctxPtr->frameInfo;
return LZ4F_decompress(dCtx, NULL, &o, NULL, &i, NULL); /* returns : recommended nb of bytes for LZ4F_decompress() */
return LZ4F_decompress(dctxPtr, NULL, &o, NULL, &i, NULL); /* returns : recommended nb of bytes for LZ4F_decompress() */
} else {
size_t nextSrcSize, o=0;
size_t const hSize = LZ4F_headerSize(srcBuffer, *srcSizePtr);
@ -937,7 +918,7 @@ LZ4F_errorCode_t LZ4F_getFrameInfo(LZ4F_decompressionContext_t dCtx, LZ4F_frameI
if (*srcSizePtr < hSize) { *srcSizePtr=0; return (size_t)-LZ4F_ERROR_frameHeader_incomplete; }
*srcSizePtr = hSize;
nextSrcSize = LZ4F_decompress(dCtx, NULL, &o, srcBuffer, srcSizePtr, NULL);
nextSrcSize = LZ4F_decompress(dctxPtr, NULL, &o, srcBuffer, srcSizePtr, NULL);
if (dctxPtr->dStage <= dstage_storeHeader) return (size_t)-LZ4F_ERROR_frameHeader_incomplete; /* should not happen, already checked */
*frameInfoPtr = dctxPtr->frameInfo;
return nextSrcSize;
@ -953,7 +934,7 @@ static int LZ4F_decompress_safe (const char* source, char* dest, int compressedS
}
static void LZ4F_updateDict(LZ4F_dctx_t* dctxPtr, const BYTE* dstPtr, size_t dstSize, const BYTE* dstPtr0, unsigned withinTmp)
static void LZ4F_updateDict(LZ4F_dctx* dctxPtr, const BYTE* dstPtr, size_t dstSize, const BYTE* dstPtr0, unsigned withinTmp)
{
if (dctxPtr->dictSize==0)
dctxPtr->dict = (const BYTE*)dstPtr; /* priority to dictionary continuity */
@ -1014,27 +995,26 @@ static void LZ4F_updateDict(LZ4F_dctx_t* dctxPtr, const BYTE* dstPtr, size_t dst
/*! LZ4F_decompress() :
* Call this function repetitively to regenerate data compressed within srcBuffer.
* The function will attempt to decode *srcSizePtr from srcBuffer, into dstBuffer of maximum size *dstSizePtr.
* The function will attempt to decode up to *srcSizePtr bytes from srcBuffer, into dstBuffer of capacity *dstSizePtr.
*
* 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 the number of bytes read is < number of bytes provided, then the decompression operation is not complete.
* You will have to call it again, continuing from where it stopped.
* 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.
* Basically, it's the size of the current (or remaining) compressed block + header of next block.
* Respecting the hint provides some boost to performance, since it allows less buffer shuffling.
* Note that this is just a hint, you can always provide any srcSize you want.
* When a frame is fully decoded, the function result will be 0.
* If decompression failed, function result is an error code which can be tested using LZ4F_isError().
* Note that this is just a hint, 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_decompressionContext_t decompressionContext,
size_t LZ4F_decompress(LZ4F_dctx* dctxPtr,
void* dstBuffer, size_t* dstSizePtr,
const void* srcBuffer, size_t* srcSizePtr,
const LZ4F_decompressOptions_t* decompressOptionsPtr)
{
LZ4F_dctx_t* dctxPtr = (LZ4F_dctx_t*)decompressionContext;
LZ4F_decompressOptions_t optionsNull;
const BYTE* const srcStart = (const BYTE*)srcBuffer;
const BYTE* const srcEnd = srcStart + *srcSizePtr;
@ -1052,11 +1032,6 @@ size_t LZ4F_decompress(LZ4F_decompressionContext_t decompressionContext,
*srcSizePtr = 0;
*dstSizePtr = 0;
/* expect to continue decoding src buffer where it left previously */
if (dctxPtr->srcExpect != NULL) {
if (srcStart != dctxPtr->srcExpect) return (size_t)-LZ4F_ERROR_srcPtr_wrong;
}
/* programmed as a state machine */
while (doAnotherStage) {
@ -1105,8 +1080,7 @@ size_t LZ4F_decompress(LZ4F_decompressionContext_t decompressionContext,
if (dctxPtr->dStage == dstage_storeCBlockSize) /* can be skipped */
case dstage_storeCBlockSize:
{
size_t sizeToCopy = BHSize - dctxPtr->tmpInSize;
{ size_t sizeToCopy = BHSize - dctxPtr->tmpInSize;
if (sizeToCopy > (size_t)(srcEnd - srcPtr)) sizeToCopy = srcEnd - srcPtr;
memcpy(dctxPtr->tmpIn + dctxPtr->tmpInSize, srcPtr, sizeToCopy);
srcPtr += sizeToCopy;
@ -1402,12 +1376,6 @@ size_t LZ4F_decompress(LZ4F_decompressionContext_t decompressionContext,
}
}
/* require function to be called again from position where it stopped */
if (srcPtr<srcEnd)
dctxPtr->srcExpect = srcPtr;
else
dctxPtr->srcExpect = NULL;
*srcSizePtr = (srcPtr - srcStart);
*dstSizePtr = (dstPtr - dstStart);
return nextSrcSizeHint;

19
lib/lz4frame.h
View File

@ -276,13 +276,13 @@ LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* dctx);
* This function decodes frame header information (such as max blockSize, frame checksum, etc.).
* Its usage is optional. The objective is to extract frame header information, typically for allocation purposes.
* A header size is variable and can length from 7 to 15 bytes. It's possible to provide more input bytes than that.
* The number of bytes read from srcBuffer will be updated within *srcSizePtr (necessarily <= original value).
* (note that LZ4F_getFrameInfo() can also be used anytime *after* decompression is started, in which case 0 input byte is enough)
* The number of bytes consumed from srcBuffer will be updated within *srcSizePtr (necessarily <= original value).
* Decompression must resume from this point (srcBuffer + *srcSizePtr).
* Note that LZ4F_getFrameInfo() can also be used anytime *after* decompression is started, in which case 0 input byte can be enough.
* Frame header info is *copied into* an already allocated LZ4F_frameInfo_t structure.
* @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()
* (typically, when there is not enough src bytes to fully decode the frame header)
* Decompression is expected to resume from where it stopped (srcBuffer + *srcSizePtr)
*/
LZ4FLIB_API size_t LZ4F_getFrameInfo(LZ4F_dctx* dctx,
LZ4F_frameInfo_t* frameInfoPtr,
@ -297,18 +297,17 @@ LZ4FLIB_API size_t LZ4F_getFrameInfo(LZ4F_dctx* dctx,
* The number of bytes read from srcBuffer will be provided within *srcSizePtr (necessarily <= original value).
* Number of bytes read can be < number of bytes provided, meaning there is some more data to decode.
* It typically happens when dstBuffer is not large enough to contain all decoded data.
* In which case, LZ4F_decompress() must be called again, starting from where it stopped (srcBuffer + *srcSizePtr)
* The function will check this condition, and refuse to continue if it is not respected.
* Remaining data will have to be presented again in a subsequent invocation.
*
* `dstBuffer` is expected to be flushed between each call to the function, its content will be overwritten.
* `dst` arguments can be changed at will at each consecutive call to the function.
* `dstBuffer` content is expected to be flushed between each invocation, as its content will be overwritten.
* `dstBuffer` can be changed at will between each consecutive function invocation.
*
* The function result is an hint of how many `srcSize` bytes LZ4F_decompress() expects for next call.
* @return is 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 boost to performance, since it does skip intermediate buffers.
* This is just a hint though, it's always possible to provide any srcSize.
* When a frame is fully decoded, the function result will be 0 (no more data expected).
* If decompression failed, function result is an error code, which can be tested using LZ4F_isError().
* When a frame is fully decoded, @return will be 0 (no more data expected).
* If decompression failed, @return is an error code, which can be tested using LZ4F_isError().
*
* After a frame is fully decoded, dctx can be used again to decompress another frame.
*/

9
tests/.gitignore vendored Normal file
View File

@ -0,0 +1,9 @@
# test build artefacts
datagen
frametest
frametest32
fullbench
fullbench32
fuzzer
fuzzer32