diff options
Diffstat (limited to 'lib/lz4frame.c')
| -rw-r--r-- | lib/lz4frame.c | 148 |
1 files changed, 111 insertions, 37 deletions
diff --git a/lib/lz4frame.c b/lib/lz4frame.c index 0c8dc53..99953c1 100644 --- a/lib/lz4frame.c +++ b/lib/lz4frame.c @@ -97,6 +97,7 @@ typedef unsigned long long U64; #define _4BITS 0x0F #define _8BITS 0xFF +#define LZ4F_MAGIC_SKIPPABLE_START 0x184D2A50U #define LZ4F_MAGICNUMBER 0x184D2204U #define LZ4F_BLOCKUNCOMPRESSED_FLAG 0x80000000U #define LZ4F_MAXHEADERFRAME_SIZE 7 @@ -213,8 +214,9 @@ size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* prefere size_t headerSize; size_t streamSize; - memset(&prefs, 0, sizeof(prefs)); if (preferencesPtr!=NULL) prefs = *preferencesPtr; + else memset(&prefs, 0, sizeof(prefs)); + { blockSizeID_t proposedBSID = max64KB; size_t maxBlockSize = 64 KB; @@ -258,13 +260,14 @@ size_t LZ4F_compressFrame(void* dstBuffer, size_t dstMaxSize, const void* srcBuf BYTE* const dstEnd = dstStart + dstMaxSize; memset(&cctxI, 0, sizeof(cctxI)); /* works because no allocation */ - memset(&prefs, 0, sizeof(prefs)); memset(&options, 0, sizeof(options)); cctxI.version = LZ4F_VERSION; cctxI.maxBufferSize = 5 MB; /* mess with real buffer size to prevent allocation; works because autoflush==1 & stableSrc==1 */ if (preferencesPtr!=NULL) prefs = *preferencesPtr; + else memset(&prefs, 0, sizeof(prefs)); + { blockSizeID_t proposedBSID = max64KB; size_t maxBlockSize = 64 KB; @@ -625,7 +628,6 @@ size_t LZ4F_compressUpdate(LZ4F_compressionContext_t compressionContext, void* d */ size_t LZ4F_flush(LZ4F_compressionContext_t compressionContext, void* dstBuffer, size_t dstMaxSize, const LZ4F_compressOptions_t* compressOptionsPtr) { - LZ4F_compressOptions_t cOptionsNull; LZ4F_cctx_internal_t* cctxPtr = (LZ4F_cctx_internal_t*)compressionContext; BYTE* const dstStart = (BYTE*)dstBuffer; BYTE* dstPtr = dstStart; @@ -635,8 +637,6 @@ size_t LZ4F_flush(LZ4F_compressionContext_t compressionContext, void* dstBuffer, if (cctxPtr->tmpInSize == 0) return 0; /* nothing to flush */ if (cctxPtr->cStage != 1) return (size_t)-ERROR_GENERIC; if (dstMaxSize < (cctxPtr->tmpInSize + 16)) return (size_t)-ERROR_dstMaxSize_tooSmall; - memset(&cOptionsNull, 0, sizeof(cOptionsNull)); - if (compressOptionsPtr == NULL) compressOptionsPtr = &cOptionsNull; (void)compressOptionsPtr; /* not yet useful */ /* select compression function */ @@ -694,9 +694,9 @@ size_t LZ4F_compressEnd(LZ4F_compressionContext_t compressionContext, void* dstB } -/*********************************** -* Decompression functions -* *********************************/ +/********************************** +* Decompression functions +**********************************/ /* Resource management */ @@ -729,8 +729,28 @@ LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_compressionContext_t LZ4F_de } -/* Decompression */ +/* ******************************************************************** */ +/* ********************* Decompression ******************************** */ +/* ******************************************************************** */ + +typedef enum { dstage_getHeader=0, dstage_storeHeader, + dstage_getCBlockSize, dstage_storeCBlockSize, + dstage_copyDirect, + dstage_getCBlock, dstage_storeCBlock, dstage_decodeCBlock, + dstage_decodeCBlock_intoDst, dstage_decodeCBlock_intoTmp, dstage_flushOut, + dstage_getSuffix, dstage_storeSuffix, + dstage_getSBlockSize, dstage_storeSBlockSize, + dstage_skipSkippable +} dStage_t; + + +/* LZ4F_decodeHeader + return : nb Bytes read from srcVoidPtr (necessarily <= srcSize) + or an error code (testable with LZ4F_isError()) + output : set internal values of dctx, such as + dctxPtr->frameInfo and dctxPtr->dStage. +*/ static size_t LZ4F_decodeHeader(LZ4F_dctx_internal_t* dctxPtr, const void* srcVoidPtr, size_t srcSize) { BYTE FLG, BD, HC; @@ -741,9 +761,19 @@ static size_t LZ4F_decodeHeader(LZ4F_dctx_internal_t* dctxPtr, const void* srcVo /* need to decode header to get frameInfo */ if (srcSize < 7) return (size_t)-ERROR_GENERIC; /* minimal header size */ + /* skippable frames */ + if ((LZ4F_readLE32(srcPtr) & 0xFFFFFFF0U) == LZ4F_MAGIC_SKIPPABLE_START) + { + memset(&(dctxPtr->frameInfo), 0, sizeof(dctxPtr->frameInfo)); + dctxPtr->frameInfo.frameType = skippableFrame; + dctxPtr->dStage = dstage_getSBlockSize; + return 4; + } + /* control magic number */ if (LZ4F_readLE32(srcPtr) != LZ4F_MAGICNUMBER) return (size_t)-ERROR_GENERIC; srcPtr += 4; + dctxPtr->frameInfo.frameType = LZ4F_frame; /* Flags */ FLG = srcPtr[0]; @@ -799,19 +829,12 @@ static size_t LZ4F_decodeHeader(LZ4F_dctx_internal_t* dctxPtr, const void* srcVo dctxPtr->tmpOutStart = 0; dctxPtr->tmpOutSize = 0; + dctxPtr->dStage = dstage_getCBlockSize; + return 7; } -typedef enum { dstage_getHeader=0, dstage_storeHeader, dstage_decodeHeader, - dstage_getCBlockSize, dstage_storeCBlockSize, - dstage_copyDirect, - dstage_getCBlock, dstage_storeCBlock, dstage_decodeCBlock, - dstage_decodeCBlock_intoDst, dstage_decodeCBlock_intoTmp, dstage_flushOut, - dstage_getSuffix, dstage_storeSuffix -} dStage_t; - - /* LZ4F_getFrameInfo() * This function decodes frame header information, such as blockSize. * It is optional : you could start by calling directly LZ4F_decompress() instead. @@ -830,11 +853,10 @@ LZ4F_errorCode_t LZ4F_getFrameInfo(LZ4F_decompressionContext_t decompressionCont { LZ4F_errorCode_t errorCode = LZ4F_decodeHeader(dctxPtr, srcBuffer, *srcSizePtr); if (LZ4F_isError(errorCode)) return errorCode; - *srcSizePtr = errorCode; + *srcSizePtr = errorCode; /* nb Bytes consumed */ *frameInfoPtr = dctxPtr->frameInfo; dctxPtr->srcExpect = NULL; - dctxPtr->dStage = dstage_getCBlockSize; - return 4; + return 4; /* nextSrcSizeHint : 4 == block header size */ } /* frameInfo already decoded */ @@ -962,7 +984,7 @@ size_t LZ4F_decompress(LZ4F_decompressionContext_t decompressionContext, /* expect to continue decoding src buffer where it left previously */ if (dctxPtr->srcExpect != NULL) { - if (srcStart != dctxPtr->srcExpect) return (size_t)-ERROR_GENERIC; + if (srcStart != dctxPtr->srcExpect) return (size_t)-ERROR_wrongSrcPtr; } /* programmed as a state machine */ @@ -977,14 +999,13 @@ size_t LZ4F_decompress(LZ4F_decompressionContext_t decompressionContext, { if (srcEnd-srcPtr >= 7) { - selectedIn = srcPtr; - srcPtr += 7; - dctxPtr->dStage = dstage_decodeHeader; + LZ4F_errorCode_t errorCode = LZ4F_decodeHeader(dctxPtr, srcPtr, srcEnd-srcPtr); + if (LZ4F_isError(errorCode)) return errorCode; + srcPtr += errorCode; break; } dctxPtr->tmpInSize = 0; dctxPtr->dStage = dstage_storeHeader; - break; } case dstage_storeHeader: @@ -997,19 +1018,17 @@ size_t LZ4F_decompress(LZ4F_decompressionContext_t decompressionContext, if (dctxPtr->tmpInSize < 7) { nextSrcSizeHint = (7 - dctxPtr->tmpInSize) + 4; - doAnotherStage = 0; /* no enough src, wait to get some more */ + doAnotherStage = 0; /* not enough src data, wait to get some more */ break; } - selectedIn = dctxPtr->header; - dctxPtr->dStage = dstage_decodeHeader; - break; - } - - case dstage_decodeHeader: - { - LZ4F_errorCode_t errorCode = LZ4F_decodeHeader(dctxPtr, selectedIn, 7); + LZ4F_errorCode_t errorCode = LZ4F_decodeHeader(dctxPtr, dctxPtr->header, 7); if (LZ4F_isError(errorCode)) return errorCode; - dctxPtr->dStage = dstage_getCBlockSize; + if (errorCode==4) + { + memcpy(dctxPtr->header, dctxPtr->header + 4, 3); + dctxPtr->tmpInSize = 3; + dctxPtr->dStage = dstage_storeSBlockSize; + } break; } @@ -1272,6 +1291,59 @@ size_t LZ4F_decompress(LZ4F_decompressionContext_t decompressionContext, doAnotherStage = 0; break; } + + case dstage_getSBlockSize: + { + if ((srcEnd - srcPtr) >= 4) + { + selectedIn = srcPtr; + srcPtr += 4; + } + else + { + /* not enough input to read cBlockSize field */ + dctxPtr->tmpInSize = 0; + dctxPtr->dStage = dstage_storeSBlockSize; + } + } + + if (dctxPtr->dStage == dstage_storeSBlockSize) + case dstage_storeSBlockSize: + { + size_t sizeToCopy = 4 - dctxPtr->tmpInSize; + if (sizeToCopy > (size_t)(srcEnd - srcPtr)) sizeToCopy = srcEnd - srcPtr; + memcpy(dctxPtr->header + dctxPtr->tmpInSize, srcPtr, sizeToCopy); + srcPtr += sizeToCopy; + dctxPtr->tmpInSize += sizeToCopy; + if (dctxPtr->tmpInSize < 4) /* not enough input to get full sBlockSize; wait for more */ + { + nextSrcSizeHint = 4 - dctxPtr->tmpInSize; + doAnotherStage=0; + break; + } + selectedIn = dctxPtr->header; + } + + /* case dstage_decodeSBlockSize: */ /* no direct access */ + { + size_t nextSBlockSize = LZ4F_readLE32(selectedIn); + dctxPtr->tmpInTarget = nextSBlockSize; + dctxPtr->dStage = dstage_skipSkippable; + break; + } + + case dstage_skipSkippable: + { + size_t skipSize = dctxPtr->tmpInTarget; + if (skipSize > (size_t)(srcEnd-srcPtr)) skipSize = srcEnd-srcPtr; + srcPtr += skipSize; + dctxPtr->tmpInTarget -= skipSize; + doAnotherStage = 0; + nextSrcSizeHint = dctxPtr->tmpInTarget; + if (nextSrcSizeHint) break; + dctxPtr->dStage = dstage_getHeader; + break; + } } } @@ -1309,10 +1381,12 @@ size_t LZ4F_decompress(LZ4F_decompressionContext_t decompressionContext, } } - if (srcPtr<srcEnd) /* function must be called again with following source data */ + /* 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; |