diff options
Diffstat (limited to 'lib/lz4frame.c')
| -rw-r--r-- | lib/lz4frame.c | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/lib/lz4frame.c b/lib/lz4frame.c index 3c2b788..a0a625b 100644 --- a/lib/lz4frame.c +++ b/lib/lz4frame.c @@ -158,7 +158,7 @@ static void LZ4F_writeLE64 (void* dst, U64 value64) #define LZ4F_BLOCKSIZEID_DEFAULT LZ4F_max64KB static const size_t minFHSize = 7; -static const size_t maxFHSize = 15; /* max Frame Header Size */ +static const size_t maxFHSize = LZ4F_HEADER_SIZE_MAX; /* 15 */ static const size_t BHSize = 4; @@ -254,20 +254,27 @@ static LZ4F_blockSizeID_t LZ4F_optimalBSID(const LZ4F_blockSizeID_t requestedBSI return requestedBSID; } +/* LZ4F_compressBound() : + * Provides dstCapacity given a srcSize to guarantee operation success in worst case situations. + * prefsPtr is optional : you can provide NULL as argument, preferences will be set to cover worst case scenario. + * Result is always the same for a srcSize and prefsPtr, so it can be trusted 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 bid = prefsPtr->frameInfo.blockSizeID; size_t const blockSize = LZ4F_getBlockSize(bid); 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 = srcSize & (blockSize-1); - size_t const lastBlockSize = prefsPtr->autoFlush ? partialBlockSize : 0; + size_t const partialBlockSize = (srcSize - (srcSize==0)) & (blockSize-1); /* 0 => -1 == MAX => blockSize-1 */ + size_t const lastBlockSize = flush ? partialBlockSize : 0; unsigned const nbBlocks = nbFullBlocks + (lastBlockSize>0); size_t const blockHeaderSize = 4; /* default, without block CRC option (which cannot be generated with current API) */ @@ -322,7 +329,7 @@ size_t LZ4F_compressFrame(void* dstBuffer, size_t dstCapacity, const void* srcBu if (prefs.frameInfo.contentSize != 0) prefs.frameInfo.contentSize = (U64)srcSize; /* auto-correct content size if selected (!=0) */ - if (prefs.compressionLevel < LZ4HC_MIN_CLEVEL) { + if (prefs.compressionLevel < LZ4HC_CLEVEL_MIN) { cctxI.lz4CtxPtr = &lz4ctx; cctxI.lz4CtxLevel = 1; } @@ -349,7 +356,7 @@ size_t LZ4F_compressFrame(void* dstBuffer, size_t dstCapacity, const void* srcBu if (LZ4F_isError(tailSize)) return tailSize; dstPtr += tailSize; } - if (prefs.compressionLevel >= LZ4HC_MIN_CLEVEL) /* no allocation done with lz4 fast */ + if (prefs.compressionLevel >= LZ4HC_CLEVEL_MIN) /* no allocation done with lz4 fast */ FREEMEM(cctxI.lz4CtxPtr); return (dstPtr - dstStart); @@ -398,7 +405,7 @@ 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 (dstCapacity). Maximum header size is LZ4F_MAXHEADERFRAME_SIZE bytes. + * dstBuffer must be large enough to accommodate a header (dstCapacity). Maximum header size is 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()) */ @@ -417,10 +424,10 @@ size_t LZ4F_compressBegin(LZ4F_cctx* cctxPtr, void* dstBuffer, size_t dstCapacit cctxPtr->prefs = *preferencesPtr; /* ctx Management */ - { U32 const tableID = (cctxPtr->prefs.compressionLevel < LZ4HC_MIN_CLEVEL) ? 1 : 2; /* 0:nothing ; 1:LZ4 table ; 2:HC tables */ + { U32 const tableID = (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN) ? 1 : 2; /* 0:nothing ; 1:LZ4 table ; 2:HC tables */ if (cctxPtr->lz4CtxLevel < tableID) { FREEMEM(cctxPtr->lz4CtxPtr); - if (cctxPtr->prefs.compressionLevel < LZ4HC_MIN_CLEVEL) + if (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN) cctxPtr->lz4CtxPtr = (void*)LZ4_createStream(); else cctxPtr->lz4CtxPtr = (void*)LZ4_createStreamHC(); @@ -445,7 +452,7 @@ size_t LZ4F_compressBegin(LZ4F_cctx* cctxPtr, void* dstBuffer, size_t dstCapacit cctxPtr->tmpIn = cctxPtr->tmpBuff; cctxPtr->tmpInSize = 0; XXH32_reset(&(cctxPtr->xxh), 0); - if (cctxPtr->prefs.compressionLevel < LZ4HC_MIN_CLEVEL) + 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); @@ -526,7 +533,7 @@ static int LZ4F_localLZ4_compressHC_limitedOutput_continue(void* ctx, const char static compressFunc_t LZ4F_selectCompression(LZ4F_blockMode_t blockMode, int level) { - if (level < LZ4HC_MIN_CLEVEL) { + if (level < LZ4HC_CLEVEL_MIN) { if (blockMode == LZ4F_blockIndependent) return LZ4F_localLZ4_compress_limitedOutput_withState; return LZ4F_localLZ4_compress_limitedOutput_continue; } @@ -536,7 +543,7 @@ static compressFunc_t LZ4F_selectCompression(LZ4F_blockMode_t blockMode, int lev static int LZ4F_localSaveDict(LZ4F_cctx_t* cctxPtr) { - if (cctxPtr->prefs.compressionLevel < LZ4HC_MIN_CLEVEL) + 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); } |