Compress-LZ4Frame
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dstPtr[2] = (BYTE)(value32 >> 16);
dstPtr[3] = (BYTE)(value32 >> 24);
}
static U64 LZ4F_readLE64 (const void* src)
{
const BYTE* const srcPtr = (const BYTE*)src;
U64 value64 = srcPtr[0];
value64 += ((U64)srcPtr[1]<<8);
value64 += ((U64)srcPtr[2]<<16);
value64 += ((U64)srcPtr[3]<<24);
value64 += ((U64)srcPtr[4]<<32);
value64 += ((U64)srcPtr[5]<<40);
value64 += ((U64)srcPtr[6]<<48);
value64 += ((U64)srcPtr[7]<<56);
return value64;
}
static void LZ4F_writeLE64 (void* dst, U64 value64)
{
BYTE* const dstPtr = (BYTE*)dst;
dstPtr[0] = (BYTE)value64;
dstPtr[1] = (BYTE)(value64 >> 8);
dstPtr[2] = (BYTE)(value64 >> 16);
dstPtr[3] = (BYTE)(value64 >> 24);
dstPtr[4] = (BYTE)(value64 >> 32);
dstPtr[5] = (BYTE)(value64 >> 40);
dstPtr[6] = (BYTE)(value64 >> 48);
dstPtr[7] = (BYTE)(value64 >> 56);
}
/*-************************************
* Constants
**************************************/
#define KB *(1<<10)
#define MB *(1<<20)
#define GB *(1<<30)
#define _1BIT 0x01
#define _2BITS 0x03
#define _3BITS 0x07
#define _4BITS 0x0F
#define _8BITS 0xFF
#define LZ4F_MAGIC_SKIPPABLE_START 0x184D2A50U
#define LZ4F_MAGICNUMBER 0x184D2204U
#define LZ4F_BLOCKUNCOMPRESSED_FLAG 0x80000000U
#define LZ4F_BLOCKSIZEID_DEFAULT LZ4F_max64KB
static const size_t minFHSize = 7;
static const size_t maxFHSize = LZ4F_HEADER_SIZE_MAX; /* 19 */
static const size_t BHSize = 4;
/*-************************************
* Structures and local types
**************************************/
typedef struct LZ4F_cctx_s
{
LZ4F_preferences_t prefs;
U32 version;
U32 cStage;
const LZ4F_CDict* cdict;
size_t maxBlockSize;
size_t maxBufferSize;
BYTE* tmpBuff;
BYTE* tmpIn;
size_t tmpInSize;
U64 totalInSize;
XXH32_state_t xxh;
void* lz4CtxPtr;
U32 lz4CtxLevel; /* 0: unallocated; 1: LZ4_stream_t; 3: LZ4_streamHC_t */
} LZ4F_cctx_t;
/*-************************************
* Error management
**************************************/
#define LZ4F_GENERATE_STRING(STRING) #STRING,
static const char* LZ4F_errorStrings[] = { LZ4F_LIST_ERRORS(LZ4F_GENERATE_STRING) };
unsigned LZ4F_isError(LZ4F_errorCode_t code)
{
return (code > (LZ4F_errorCode_t)(-LZ4F_ERROR_maxCode));
}
const char* LZ4F_getErrorName(LZ4F_errorCode_t code)
{
static const char* codeError = "Unspecified error code";
if (LZ4F_isError(code)) return LZ4F_errorStrings[-(int)(code)];
return codeError;
}
LZ4F_errorCodes LZ4F_getErrorCode(size_t functionResult)
{
if (!LZ4F_isError(functionResult)) return LZ4F_OK_NoError;
return (LZ4F_errorCodes)(-(ptrdiff_t)functionResult);
}
static LZ4F_errorCode_t err0r(LZ4F_errorCodes code)
{
/* A compilation error here means sizeof(ptrdiff_t) is not large enough */
LZ4F_STATIC_ASSERT(sizeof(ptrdiff_t) >= sizeof(size_t));
return (LZ4F_errorCode_t)-(ptrdiff_t)code;
}
unsigned LZ4F_getVersion(void) { return LZ4F_VERSION; }
int LZ4F_compressionLevel_max(void) { return LZ4HC_CLEVEL_MAX; }
/*-************************************
* Private functions
**************************************/
#define MIN(a,b) ( (a) < (b) ? (a) : (b) )
static size_t LZ4F_getBlockSize(unsigned blockSizeID)
{
static const size_t blockSizes[4] = { 64 KB, 256 KB, 1 MB, 4 MB };
if (blockSizeID == 0) blockSizeID = LZ4F_BLOCKSIZEID_DEFAULT;
blockSizeID -= 4;
if (blockSizeID > 3) return err0r(LZ4F_ERROR_maxBlockSize_invalid);
return blockSizes[blockSizeID];
}
static BYTE LZ4F_headerChecksum (const void* header, size_t length)
{
U32 const xxh = XXH32(header, length, 0);
return (BYTE)(xxh >> 8);
}
/*-************************************
* Simple-pass compression functions
**************************************/
static LZ4F_blockSizeID_t LZ4F_optimalBSID(const LZ4F_blockSizeID_t requestedBSID,
const size_t srcSize)
{
LZ4F_blockSizeID_t proposedBSID = LZ4F_max64KB;
size_t maxBlockSize = 64 KB;
while (requestedBSID > proposedBSID) {
if (srcSize <= maxBlockSize)
return proposedBSID;
proposedBSID = (LZ4F_blockSizeID_t)((int)proposedBSID + 1);
maxBlockSize <<= 2;
}
return requestedBSID;
}
/*! LZ4F_compressBound_internal() :
* Provides dstCapacity given a srcSize to guarantee operation success in worst case situations.
* prefsPtr is optional : if NULL is provided, preferences will be set to cover worst case scenario.
* @return is always the same for a srcSize and prefsPtr, so it can be relied upon to size reusable buffers.
* When srcSize==0, LZ4F_compressBound() provides an upper bound for LZ4F_flush() and LZ4F_compressEnd() operations.
*/
static size_t LZ4F_compressBound_internal(size_t srcSize,
const LZ4F_preferences_t* preferencesPtr,
size_t alreadyBuffered)
{
LZ4F_preferences_t prefsNull;
memset(&prefsNull, 0, sizeof(prefsNull));
prefsNull.frameInfo.contentChecksumFlag = LZ4F_contentChecksumEnabled; /* worst case */
{ const LZ4F_preferences_t* const prefsPtr = (preferencesPtr==NULL) ? &prefsNull : preferencesPtr;
U32 const flush = prefsPtr->autoFlush | (srcSize==0);
LZ4F_blockSizeID_t const blockID = prefsPtr->frameInfo.blockSizeID;
size_t const blockSize = LZ4F_getBlockSize(blockID);
size_t const maxBuffered = blockSize - 1;
size_t const bufferedSize = MIN(alreadyBuffered, maxBuffered);
size_t const maxSrcSize = srcSize + bufferedSize;
unsigned const nbFullBlocks = (unsigned)(maxSrcSize / blockSize);
size_t const partialBlockSize = maxSrcSize & (blockSize-1);
size_t const lastBlockSize = flush ? partialBlockSize : 0;
unsigned const nbBlocks = nbFullBlocks + (lastBlockSize>0);
size_t const blockHeaderSize = 4;
size_t const blockCRCSize = 4 * prefsPtr->frameInfo.blockChecksumFlag;
size_t const frameEnd = 4 + (prefsPtr->frameInfo.contentChecksumFlag*4);
return ((blockHeaderSize + blockCRCSize) * nbBlocks) +
(blockSize * nbFullBlocks) + lastBlockSize + frameEnd;
}
}
size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr)
{
LZ4F_preferences_t prefs;
size_t const headerSize = maxFHSize; /* max header size, including optional fields */
if (preferencesPtr!=NULL) prefs = *preferencesPtr;
else memset(&prefs, 0, sizeof(prefs));
prefs.autoFlush = 1;
return headerSize + LZ4F_compressBound_internal(srcSize, &prefs, 0);;
}
/*! LZ4F_compressFrame_usingCDict() :
* Compress srcBuffer using a dictionary, in a single step.
* cdict can be NULL, in which case, no dictionary is used.
* dstBuffer MUST be >= LZ4F_compressFrameBound(srcSize, preferencesPtr).
* The LZ4F_preferences_t structure is optional : you may provide NULL as argument,
* however, it's the only way to provide a dictID, so it's not recommended.
* @return : number of bytes written into dstBuffer,
* or an error code if it fails (can be tested using LZ4F_isError())
*/
size_t LZ4F_compressFrame_usingCDict(void* dstBuffer, size_t dstCapacity,
const void* srcBuffer, size_t srcSize,
const LZ4F_CDict* cdict,
const LZ4F_preferences_t* preferencesPtr)
{
LZ4F_cctx_t cctxI;
LZ4_stream_t lz4ctx; /* pretty large on stack */
LZ4F_preferences_t prefs;
LZ4F_compressOptions_t options;
BYTE* const dstStart = (BYTE*) dstBuffer;
BYTE* dstPtr = dstStart;
BYTE* const dstEnd = dstStart + dstCapacity;
memset(&cctxI, 0, sizeof(cctxI));
cctxI.version = LZ4F_VERSION;
cctxI.maxBufferSize = 5 MB; /* mess with real buffer size to prevent dynamic allocation; works only because autoflush==1 & stableSrc==1 */
if (preferencesPtr!=NULL)
prefs = *preferencesPtr;
else
memset(&prefs, 0, sizeof(prefs));
if (prefs.frameInfo.contentSize != 0)
prefs.frameInfo.contentSize = (U64)srcSize; /* auto-correct content size if selected (!=0) */
prefs.frameInfo.blockSizeID = LZ4F_optimalBSID(prefs.frameInfo.blockSizeID, srcSize);
prefs.autoFlush = 1;
if (srcSize <= LZ4F_getBlockSize(prefs.frameInfo.blockSizeID))
prefs.frameInfo.blockMode = LZ4F_blockIndependent; /* only one block => no need for inter-block link */
if (prefs.compressionLevel < LZ4HC_CLEVEL_MIN) {
cctxI.lz4CtxPtr = &lz4ctx;
cctxI.lz4CtxLevel = 1;
} /* fast compression context pre-created on stack */
memset(&options, 0, sizeof(options));
options.stableSrc = 1;
if (dstCapacity < LZ4F_compressFrameBound(srcSize, &prefs)) /* condition to guarantee success */
return err0r(LZ4F_ERROR_dstMaxSize_tooSmall);
{ size_t const headerSize = LZ4F_compressBegin_usingCDict(&cctxI, dstBuffer, dstCapacity, cdict, &prefs); /* write header */
if (LZ4F_isError(headerSize)) return headerSize;
dstPtr += headerSize; /* header size */ }
{ size_t const cSize = LZ4F_compressUpdate(&cctxI, dstPtr, dstEnd-dstPtr, srcBuffer, srcSize, &options);
if (LZ4F_isError(cSize)) return cSize;
dstPtr += cSize; }
{ 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_CLEVEL_MIN) /* Ctx allocation only for lz4hc */
FREEMEM(cctxI.lz4CtxPtr);
return (dstPtr - dstStart);
}
/*! LZ4F_compressFrame() :
* Compress an entire srcBuffer into a valid LZ4 frame, in a single step.
* dstBuffer MUST be >= LZ4F_compressFrameBound(srcSize, preferencesPtr).
* The LZ4F_preferences_t structure is optional : you can provide NULL as argument. All preferences will be set to default.
* @return : number of bytes written into dstBuffer.
* or an error code if it fails (can be tested using LZ4F_isError())
*/
size_t LZ4F_compressFrame(void* dstBuffer, size_t dstCapacity,
const void* srcBuffer, size_t srcSize,
const LZ4F_preferences_t* preferencesPtr)
{
return LZ4F_compressFrame_usingCDict(dstBuffer, dstCapacity,
srcBuffer, srcSize,
NULL, preferencesPtr);
}
/*-***************************************************
* Dictionary compression
*****************************************************/
struct LZ4F_CDict_s {
void* dictContent;
LZ4_stream_t* fastCtx;
LZ4_streamHC_t* HCCtx;
}; /* typedef'd to LZ4F_CDict within lz4frame_static.h */
/*! LZ4F_createCDict() :
* When compressing multiple messages / blocks with the same dictionary, it's recommended to load it just once.
* LZ4F_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay.
* LZ4F_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only.
* `dictBuffer` can be released after LZ4F_CDict creation, since its content is copied within CDict
* @return : digested dictionary for compression, or NULL if failed */
LZ4F_CDict* LZ4F_createCDict(const void* dictBuffer, size_t dictSize)
{
const char* dictStart = (const char*)dictBuffer;
LZ4F_CDict* cdict = (LZ4F_CDict*) malloc(sizeof(*cdict));
if (!cdict) return NULL;
if (dictSize > 64 KB) {
dictStart += dictSize - 64 KB;
dictSize = 64 KB;
}
cdict->dictContent = ALLOCATOR(dictSize);
cdict->fastCtx = LZ4_createStream();
cdict->HCCtx = LZ4_createStreamHC();
if (!cdict->dictContent || !cdict->fastCtx || !cdict->HCCtx) {
LZ4F_freeCDict(cdict);
return NULL;
}
memcpy(cdict->dictContent, dictStart, dictSize);
LZ4_resetStream(cdict->fastCtx);
LZ4_loadDict (cdict->fastCtx, (const char*)cdict->dictContent, (int)dictSize);
LZ4_resetStreamHC(cdict->HCCtx, LZ4HC_CLEVEL_DEFAULT);
LZ4_loadDictHC(cdict->HCCtx, (const char*)cdict->dictContent, (int)dictSize);
/*-*********************************
* 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 incompatible 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* const cctxPtr = (LZ4F_cctx_t*)ALLOCATOR(sizeof(LZ4F_cctx_t));
if (cctxPtr==NULL) return err0r(LZ4F_ERROR_allocation_failed);
cctxPtr->version = version;
cctxPtr->cStage = 0; /* Next stage : init stream */
*LZ4F_compressionContextPtr = (LZ4F_compressionContext_t)cctxPtr;
return LZ4F_OK_NoError;
}
LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_compressionContext_t LZ4F_compressionContext)
{
LZ4F_cctx_t* const cctxPtr = (LZ4F_cctx_t*)LZ4F_compressionContext;
if (cctxPtr != NULL) { /* support free on NULL */
FREEMEM(cctxPtr->lz4CtxPtr); /* works because LZ4_streamHC_t and LZ4_stream_t are simple POD types */
FREEMEM(cctxPtr->tmpBuff);
FREEMEM(LZ4F_compressionContext);
}
return LZ4F_OK_NoError;
}
/*! LZ4F_compressBegin_usingCDict() :
* init streaming compression and writes frame header into dstBuffer.
* dstBuffer must be >= LZ4F_HEADER_SIZE_MAX 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_usingCDict(LZ4F_cctx* cctxPtr,
void* dstBuffer, size_t dstCapacity,
const LZ4F_CDict* cdict,
const LZ4F_preferences_t* preferencesPtr)
{
LZ4F_preferences_t prefNull;
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* dstPtr = dstStart;
BYTE* headerStart;
if (dstCapacity < maxFHSize) return err0r(LZ4F_ERROR_dstMaxSize_tooSmall);
memset(&prefNull, 0, sizeof(prefNull));
if (preferencesPtr == NULL) preferencesPtr = &prefNull;
cctxPtr->prefs = *preferencesPtr;
/* Ctx Management */
{ U32 const ctxTypeID = (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN) ? 1 : 2; /* 0:nothing ; 1:LZ4 table ; 2:HC tables */
if (cctxPtr->lz4CtxLevel < ctxTypeID) {
FREEMEM(cctxPtr->lz4CtxPtr);
if (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN)
cctxPtr->lz4CtxPtr = (void*)LZ4_createStream();
else
cctxPtr->lz4CtxPtr = (void*)LZ4_createStreamHC();
if (cctxPtr->lz4CtxPtr == NULL) return err0r(LZ4F_ERROR_allocation_failed);
cctxPtr->lz4CtxLevel = ctxTypeID;
} }
/* Buffer Management */
if (cctxPtr->prefs.frameInfo.blockSizeID == 0)
cctxPtr->prefs.frameInfo.blockSizeID = LZ4F_BLOCKSIZEID_DEFAULT;
cctxPtr->maxBlockSize = LZ4F_getBlockSize(cctxPtr->prefs.frameInfo.blockSizeID);
{ size_t const requiredBuffSize = preferencesPtr->autoFlush ?
(cctxPtr->prefs.frameInfo.blockMode == LZ4F_blockLinked) * 64 KB : /* only needs windows size */
cctxPtr->maxBlockSize + ((cctxPtr->prefs.frameInfo.blockMode == LZ4F_blockLinked) * 128 KB);
if (cctxPtr->maxBufferSize < requiredBuffSize) {
cctxPtr->maxBufferSize = 0;
FREEMEM(cctxPtr->tmpBuff);
cctxPtr->tmpBuff = (BYTE*)ALLOCATOR(requiredBuffSize);
if (cctxPtr->tmpBuff == NULL) return err0r(LZ4F_ERROR_allocation_failed);
cctxPtr->maxBufferSize = requiredBuffSize;
} }
cctxPtr->tmpIn = cctxPtr->tmpBuff;
cctxPtr->tmpInSize = 0;
XXH32_reset(&(cctxPtr->xxh), 0);
/* context init */
cctxPtr->cdict = cdict;
if (cctxPtr->prefs.frameInfo.blockMode == LZ4F_blockLinked) {
/* frame init only for blockLinked : blockIndependent will be init at each block */
if (cdict) {
if (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN) {
memcpy(cctxPtr->lz4CtxPtr, cdict->fastCtx, sizeof(*cdict->fastCtx));
} else {
memcpy(cctxPtr->lz4CtxPtr, cdict->HCCtx, sizeof(*cdict->HCCtx));
LZ4_setCompressionLevel((LZ4_streamHC_t*)cctxPtr->lz4CtxPtr, cctxPtr->prefs.compressionLevel);
}
} else {
if (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN)
LZ4_resetStream((LZ4_stream_t*)(cctxPtr->lz4CtxPtr));
else
LZ4_resetStreamHC((LZ4_streamHC_t*)(cctxPtr->lz4CtxPtr), cctxPtr->prefs.compressionLevel);
}
}
/* Magic Number */
LZ4F_writeLE32(dstPtr, LZ4F_MAGICNUMBER);
dstPtr += 4;
headerStart = dstPtr;
/* FLG Byte */
*dstPtr++ = (BYTE)(((1 & _2BITS) << 6) /* Version('01') */
+ ((cctxPtr->prefs.frameInfo.blockMode & _1BIT ) << 5)
+ ((cctxPtr->prefs.frameInfo.blockChecksumFlag & _1BIT ) << 4)
+ ((cctxPtr->prefs.frameInfo.contentSize > 0) << 3)
+ ((cctxPtr->prefs.frameInfo.contentChecksumFlag & _1BIT ) << 2)
+ (cctxPtr->prefs.frameInfo.dictID > 0) );
/* BD Byte */
*dstPtr++ = (BYTE)((cctxPtr->prefs.frameInfo.blockSizeID & _3BITS) << 4);
/* Optional Frame content size field */
if (cctxPtr->prefs.frameInfo.contentSize) {
LZ4F_writeLE64(dstPtr, cctxPtr->prefs.frameInfo.contentSize);
dstPtr += 8;
cctxPtr->totalInSize = 0;
}
/* Optional dictionary ID field */
if (cctxPtr->prefs.frameInfo.dictID) {
LZ4F_writeLE32(dstPtr, cctxPtr->prefs.frameInfo.dictID);
dstPtr += 4;
}
/* Header CRC Byte */
*dstPtr = LZ4F_headerChecksum(headerStart, dstPtr - headerStart);
dstPtr++;
cctxPtr->cStage = 1; /* header written, now request input data block */
return (dstPtr - dstStart);
}
/*! LZ4F_compressBegin() :
* init streaming compression and writes frame header into dstBuffer.
* dstBuffer must be >= LZ4F_HEADER_SIZE_MAX bytes.
* preferencesPtr can be NULL, in which case default parameters are selected.
* @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 dstCapacity,
const LZ4F_preferences_t* preferencesPtr)
{
return LZ4F_compressBegin_usingCDict(cctxPtr, dstBuffer, dstCapacity,
NULL, preferencesPtr);
}
/* LZ4F_compressBound() :
* @return minimum capacity of dstBuffer for a given srcSize to handle worst case scenario.
* LZ4F_preferences_t structure is optional : if NULL, preferences will be set to cover worst case scenario.
* This function cannot fail.
*/
size_t LZ4F_compressBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr)
{
return LZ4F_compressBound_internal(srcSize, preferencesPtr, (size_t)-1);
}
typedef int (*compressFunc_t)(void* ctx, const char* src, char* dst, int srcSize, int dstSize, int level, const LZ4F_CDict* cdict);
/*! LZ4F_makeBlock():
* compress a single block, add header and checksum
* assumption : dst buffer capacity is >= srcSize */
static size_t LZ4F_makeBlock(void* dst, const void* src, size_t srcSize,
compressFunc_t compress, void* lz4ctx, int level,
const LZ4F_CDict* cdict, LZ4F_blockChecksum_t crcFlag)
{
BYTE* const cSizePtr = (BYTE*)dst;
U32 cSize = (U32)compress(lz4ctx, (const char*)src, (char*)(cSizePtr+4),
(int)(srcSize), (int)(srcSize-1),
level, cdict);
LZ4F_writeLE32(cSizePtr, cSize);
if (cSize == 0) { /* compression failed */
cSize = (U32)srcSize;
LZ4F_writeLE32(cSizePtr, cSize | LZ4F_BLOCKUNCOMPRESSED_FLAG);
memcpy(cSizePtr+4, src, srcSize);
}
if (crcFlag) {
U32 const crc32 = XXH32(cSizePtr+4, cSize, 0); /* checksum of compressed data */
LZ4F_writeLE32(cSizePtr+4+cSize, crc32);
}
return 4 + cSize + ((U32)crcFlag)*4;
}
static int LZ4F_compressBlock(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)
{
int const acceleration = (level < -1) ? -level : 1;
if (cdict) {
memcpy(ctx, cdict->fastCtx, sizeof(*cdict->fastCtx));
return LZ4_compress_fast_continue((LZ4_stream_t*)ctx, src, dst, srcSize, dstCapacity, acceleration);
}
return LZ4_compress_fast_extState(ctx, src, dst, srcSize, dstCapacity, acceleration);
}
static int LZ4F_compressBlock_continue(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)
{
int const acceleration = (level < -1) ? -level : 1;
(void)cdict; /* init once at beginning of frame */
return LZ4_compress_fast_continue((LZ4_stream_t*)ctx, src, dst, srcSize, dstCapacity, acceleration);
}
static int LZ4F_compressBlockHC(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)
{
if (cdict) {
memcpy(ctx, cdict->HCCtx, sizeof(*cdict->HCCtx));
LZ4_setCompressionLevel((LZ4_streamHC_t*)ctx, level);
return LZ4_compress_HC_continue((LZ4_streamHC_t*)ctx, src, dst, srcSize, dstCapacity);
}
return LZ4_compress_HC_extStateHC(ctx, src, dst, srcSize, dstCapacity, level);
}
static int LZ4F_compressBlockHC_continue(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)
{
(void)level; (void)cdict; /* init once at beginning of frame */
return LZ4_compress_HC_continue((LZ4_streamHC_t*)ctx, src, dst, srcSize, dstCapacity);
}
static compressFunc_t LZ4F_selectCompression(LZ4F_blockMode_t blockMode, int level)
{
if (level < LZ4HC_CLEVEL_MIN) {
if (blockMode == LZ4F_blockIndependent) return LZ4F_compressBlock;
return LZ4F_compressBlock_continue;
}
if (blockMode == LZ4F_blockIndependent) return LZ4F_compressBlockHC;
return LZ4F_compressBlockHC_continue;
}
static int LZ4F_localSaveDict(LZ4F_cctx_t* cctxPtr)
{
if (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN)
return LZ4_saveDict ((LZ4_stream_t*)(cctxPtr->lz4CtxPtr), (char*)(cctxPtr->tmpBuff), 64 KB);
return LZ4_saveDictHC ((LZ4_streamHC_t*)(cctxPtr->lz4CtxPtr), (char*)(cctxPtr->tmpBuff), 64 KB);
}
typedef enum { notDone, fromTmpBuffer, fromSrcBuffer } LZ4F_lastBlockStatus;
/*! LZ4F_compressUpdate() :
* LZ4F_compressUpdate() can be called repetitively to compress as much data as necessary.
* dstBuffer MUST be >= LZ4F_compressBound(srcSize, preferencesPtr).
* LZ4F_compressOptions_t structure is optional : you can provide NULL as argument.
* @return : the number of bytes written into dstBuffer. It can be zero, meaning input data was just buffered.
* or an error code if it fails (which can be tested using LZ4F_isError())
*/
size_t LZ4F_compressUpdate(LZ4F_cctx* cctxPtr,
void* dstBuffer, size_t dstCapacity,
const void* srcBuffer, size_t srcSize,
const LZ4F_compressOptions_t* compressOptionsPtr)
{
LZ4F_compressOptions_t cOptionsNull;
size_t const blockSize = cctxPtr->maxBlockSize;
const BYTE* srcPtr = (const BYTE*)srcBuffer;
const BYTE* const srcEnd = srcPtr + srcSize;
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* dstPtr = dstStart;
LZ4F_lastBlockStatus lastBlockCompressed = notDone;
compressFunc_t const compress = LZ4F_selectCompression(cctxPtr->prefs.frameInfo.blockMode, cctxPtr->prefs.compressionLevel);
if (cctxPtr->cStage != 1) return err0r(LZ4F_ERROR_GENERIC);
if (dstCapacity < LZ4F_compressBound_internal(srcSize, &(cctxPtr->prefs), cctxPtr->tmpInSize)) return err0r(LZ4F_ERROR_dstMaxSize_tooSmall);
memset(&cOptionsNull, 0, sizeof(cOptionsNull));
if (compressOptionsPtr == NULL) compressOptionsPtr = &cOptionsNull;
/* complete tmp buffer */
if (cctxPtr->tmpInSize > 0) { /* some data already within tmp buffer */
size_t const sizeToCopy = blockSize - cctxPtr->tmpInSize;
if (sizeToCopy > srcSize) {
/* add src to tmpIn buffer */
memcpy(cctxPtr->tmpIn + cctxPtr->tmpInSize, srcBuffer, srcSize);
srcPtr = srcEnd;
cctxPtr->tmpInSize += srcSize;
/* still needs some CRC */
} else {
/* complete tmpIn block and then compress it */
lastBlockCompressed = fromTmpBuffer;
memcpy(cctxPtr->tmpIn + cctxPtr->tmpInSize, srcBuffer, sizeToCopy);
srcPtr += sizeToCopy;
dstPtr += LZ4F_makeBlock(dstPtr, cctxPtr->tmpIn, blockSize,
compress, cctxPtr->lz4CtxPtr, cctxPtr->prefs.compressionLevel,
cctxPtr->cdict, cctxPtr->prefs.frameInfo.blockChecksumFlag);
if (cctxPtr->prefs.frameInfo.blockMode==LZ4F_blockLinked) cctxPtr->tmpIn += blockSize;
cctxPtr->tmpInSize = 0;
}
}
while ((size_t)(srcEnd - srcPtr) >= blockSize) {
/* compress full blocks */
lastBlockCompressed = fromSrcBuffer;
dstPtr += LZ4F_makeBlock(dstPtr, srcPtr, blockSize,
compress, cctxPtr->lz4CtxPtr, cctxPtr->prefs.compressionLevel,
cctxPtr->cdict, cctxPtr->prefs.frameInfo.blockChecksumFlag);
srcPtr += blockSize;
}
if ((cctxPtr->prefs.autoFlush) && (srcPtr < srcEnd)) {
/* compress remaining input < blockSize */
lastBlockCompressed = fromSrcBuffer;
dstPtr += LZ4F_makeBlock(dstPtr, srcPtr, srcEnd - srcPtr,
compress, cctxPtr->lz4CtxPtr, cctxPtr->prefs.compressionLevel,
cctxPtr->cdict, cctxPtr->prefs.frameInfo.blockChecksumFlag);
srcPtr = srcEnd;
}
/* preserve dictionary if necessary */
if ((cctxPtr->prefs.frameInfo.blockMode==LZ4F_blockLinked) && (lastBlockCompressed==fromSrcBuffer)) {
if (compressOptionsPtr->stableSrc) {
cctxPtr->tmpIn = cctxPtr->tmpBuff;
} else {
int const realDictSize = LZ4F_localSaveDict(cctxPtr);
if (realDictSize==0) return err0r(LZ4F_ERROR_GENERIC);
cctxPtr->tmpIn = cctxPtr->tmpBuff + realDictSize;
}
}
/* keep tmpIn within limits */
if ((cctxPtr->tmpIn + blockSize) > (cctxPtr->tmpBuff + cctxPtr->maxBufferSize) /* necessarily LZ4F_blockLinked && lastBlockCompressed==fromTmpBuffer */
&& !(cctxPtr->prefs.autoFlush))
{
int const realDictSize = LZ4F_localSaveDict(cctxPtr);
cctxPtr->tmpIn = cctxPtr->tmpBuff + realDictSize;
}
/* some input data left, necessarily < blockSize */
if (srcPtr < srcEnd) {
/* fill tmp buffer */
size_t const sizeToCopy = srcEnd - srcPtr;
memcpy(cctxPtr->tmpIn, srcPtr, sizeToCopy);
cctxPtr->tmpInSize = sizeToCopy;
}
if (cctxPtr->prefs.frameInfo.contentChecksumFlag == LZ4F_contentChecksumEnabled)
XXH32_update(&(cctxPtr->xxh), srcBuffer, srcSize);
cctxPtr->totalInSize += srcSize;
return dstPtr - dstStart;
}
/*! LZ4F_flush() :
* Should you need to create compressed data immediately, without waiting for a block to be filled,
* you can call LZ4_flush(), which will immediately compress any remaining data stored within compressionContext.
* The result of the function is the number of bytes written into dstBuffer
* (it can be zero, this means there was no data left within compressionContext)
* 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_cctx* cctxPtr, void* dstBuffer, size_t dstCapacity, const LZ4F_compressOptions_t* compressOptionsPtr)
{
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 err0r(LZ4F_ERROR_GENERIC);
if (dstCapacity < (cctxPtr->tmpInSize + 4)) return err0r(LZ4F_ERROR_dstMaxSize_tooSmall); /* +4 : block header(4) */
(void)compressOptionsPtr; /* not yet useful */
/* select compression function */
compress = LZ4F_selectCompression(cctxPtr->prefs.frameInfo.blockMode, cctxPtr->prefs.compressionLevel);
/* compress tmp buffer */
dstPtr += LZ4F_makeBlock(dstPtr, cctxPtr->tmpIn, cctxPtr->tmpInSize,
compress, cctxPtr->lz4CtxPtr, cctxPtr->prefs.compressionLevel,
cctxPtr->cdict, cctxPtr->prefs.frameInfo.blockChecksumFlag);
if (cctxPtr->prefs.frameInfo.blockMode==LZ4F_blockLinked) cctxPtr->tmpIn += cctxPtr->tmpInSize;
cctxPtr->tmpInSize = 0;
/* keep tmpIn within limits */
if ((cctxPtr->tmpIn + cctxPtr->maxBlockSize) > (cctxPtr->tmpBuff + cctxPtr->maxBufferSize)) { /* necessarily LZ4F_blockLinked */
int realDictSize = LZ4F_localSaveDict(cctxPtr);
cctxPtr->tmpIn = cctxPtr->tmpBuff + realDictSize;
}
return dstPtr - dstStart;
}
/*! LZ4F_compressEnd() :
* When you want to properly finish the compressed frame, just call LZ4F_compressEnd().
* It will flush whatever data remained within compressionContext (like LZ4_flush())
* but also properly finalize the frame, with an endMark and a checksum.
* The result of the function is the number of bytes written into dstBuffer (necessarily >= 4 (endMark size))
* 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.
* compressionContext can then be used again, starting with LZ4F_compressBegin(). The preferences will remain the same.
*/
size_t LZ4F_compressEnd(LZ4F_cctx* cctxPtr, void* dstBuffer, size_t dstMaxSize, const LZ4F_compressOptions_t* compressOptionsPtr)
{
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* dstPtr = dstStart;
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 const xxh = XXH32_digest(&(cctxPtr->xxh));
LZ4F_writeLE32(dstPtr, xxh);
dstPtr+=4; /* content Checksum */
}
cctxPtr->cStage = 0; /* state is now re-usable (with identical preferences) */
cctxPtr->maxBufferSize = 0; /* reuse HC context */
if (cctxPtr->prefs.frameInfo.contentSize) {
if (cctxPtr->prefs.frameInfo.contentSize != cctxPtr->totalInSize)
return err0r(LZ4F_ERROR_frameSize_wrong);
}
return dstPtr - dstStart;
}
/*-***************************************************
* Frame Decompression
*****************************************************/
typedef enum {
dstage_getFrameHeader=0, dstage_storeFrameHeader,
dstage_init,
dstage_getBlockHeader, dstage_storeBlockHeader,
dstage_copyDirect, dstage_getBlockChecksum,
dstage_getCBlock, dstage_storeCBlock,
dstage_flushOut,
dstage_getSuffix, dstage_storeSuffix,
dstage_getSFrameSize, dstage_storeSFrameSize,
dstage_skipSkippable
} dStage_t;
struct LZ4F_dctx_s {
LZ4F_frameInfo_t frameInfo;
U32 version;
dStage_t 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;
XXH32_state_t blockChecksum;
BYTE header[LZ4F_HEADER_SIZE_MAX];
}; /* typedef'd to LZ4F_dctx in lz4frame.h */
/*! LZ4F_createDecompressionContext() :
* Create a decompressionContext object, which will track all decompression operations.
* Provides a pointer to a fully allocated and initialized LZ4F_decompressionContext object.
* Object can later be released using LZ4F_freeDecompressionContext().
* @return : if != 0, there was an error during context creation.
*/
LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_dctx** LZ4F_decompressionContextPtr, unsigned versionNumber)
{
LZ4F_dctx* const dctx = (LZ4F_dctx*)ALLOCATOR(sizeof(LZ4F_dctx));
if (dctx==NULL) return err0r(LZ4F_ERROR_GENERIC);
dctx->version = versionNumber;
*LZ4F_decompressionContextPtr = dctx;
return LZ4F_OK_NoError;
}
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