/* * LZ4 auto-framing library * Copyright (C) 2011-2016, Yann Collet. * * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * You can contact the author at : * - LZ4 homepage : http://www.lz4.org * - LZ4 source repository : https://github.com/lz4/lz4 */ /* LZ4F is a stand-alone API to create LZ4-compressed Frames * in full conformance with specification v1.6.1 . * This library rely upon memory management capabilities (malloc, free) * provided either by , * or redirected towards another library of user's choice * (see Memory Routines below). */ /*-************************************ * Compiler Options **************************************/ #ifdef _MSC_VER /* Visual Studio */ # pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */ #endif /*-************************************ * Tuning parameters **************************************/ /* * LZ4F_HEAPMODE : * Select how default compression functions will allocate memory for their hash table, * in memory stack (0:default, fastest), or in memory heap (1:requires malloc()). */ #ifndef LZ4F_HEAPMODE # define LZ4F_HEAPMODE 0 #endif /*-************************************ * Memory routines **************************************/ /* * User may redirect invocations of * malloc(), calloc() and free() * towards another library or solution of their choice * by modifying below section. */ #include /* malloc, calloc, free */ #define ALLOC(s) malloc(s) #ifndef LZ4_SRC_INCLUDED /* avoid redefinition when sources are coalesced */ # define ALLOC_AND_ZERO(s) calloc(1,(s)) #endif #define FREEMEM(p) free(p) #include /* memset, memcpy, memmove */ #ifndef LZ4_SRC_INCLUDED /* avoid redefinition when sources are coalesced */ # define MEM_INIT memset #endif /*-************************************ * Library declarations **************************************/ #define LZ4F_STATIC_LINKING_ONLY #include "lz4frame.h" #define LZ4_STATIC_LINKING_ONLY #include "lz4.h" #define LZ4_HC_STATIC_LINKING_ONLY #include "lz4hc.h" #define XXH_STATIC_LINKING_ONLY #include "xxhash.h" /*-************************************ * Debug **************************************/ #if defined(LZ4_DEBUG) && (LZ4_DEBUG>=1) # include #else # ifndef assert # define assert(condition) ((void)0) # endif #endif #define LZ4F_STATIC_ASSERT(c) { enum { LZ4F_static_assert = 1/(int)(!!(c)) }; } /* use only *after* variable declarations */ #if defined(LZ4_DEBUG) && (LZ4_DEBUG>=2) && !defined(DEBUGLOG) # include static int g_debuglog_enable = 1; # define DEBUGLOG(l, ...) { \ if ((g_debuglog_enable) && (l<=LZ4_DEBUG)) { \ fprintf(stderr, __FILE__ ": "); \ fprintf(stderr, __VA_ARGS__); \ fprintf(stderr, " \n"); \ } } #else # define DEBUGLOG(l, ...) {} /* disabled */ #endif /*-************************************ * Basic Types **************************************/ #if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) ) # include typedef uint8_t BYTE; typedef uint16_t U16; typedef uint32_t U32; typedef int32_t S32; typedef uint64_t U64; #else typedef unsigned char BYTE; typedef unsigned short U16; typedef unsigned int U32; typedef signed int S32; typedef unsigned long long U64; #endif /* unoptimized version; solves endianess & alignment issues */ static U32 LZ4F_readLE32 (const void* src) { const BYTE* const srcPtr = (const BYTE*)src; U32 value32 = srcPtr[0]; value32 += ((U32)srcPtr[1])<< 8; value32 += ((U32)srcPtr[2])<<16; value32 += ((U32)srcPtr[3])<<24; return value32; } static void LZ4F_writeLE32 (void* dst, U32 value32) { BYTE* const dstPtr = (BYTE*)dst; dstPtr[0] = (BYTE)value32; dstPtr[1] = (BYTE)(value32 >> 8); 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 **************************************/ #ifndef LZ4_SRC_INCLUDED #define KB *(1<<10) #define MB *(1<<20) #define GB *(1<<30) #endif #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; /* block header : size, and compress flag */ static const size_t BFSize = 4; /* block footer : checksum (optional) */ /*-************************************ * 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; U16 lz4CtxAlloc; /* sized for: 0 = none, 1 = lz4 ctx, 2 = lz4hc ctx */ U16 lz4CtxState; /* in use as: 0 = none, 1 = lz4 ctx, 2 = lz4hc ctx */ } 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; } 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; if (blockSizeID < 4 || blockSizeID > 7) return err0r(LZ4F_ERROR_maxBlockSize_invalid); blockSizeID -= 4; return blockSizes[blockSizeID]; } /*-************************************ * Private functions **************************************/ #define MIN(a,b) ( (a) < (b) ? (a) : (b) ) 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; MEM_INIT(&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 blockCRCSize = BFSize * prefsPtr->frameInfo.blockChecksumFlag; size_t const frameEnd = BHSize + (prefsPtr->frameInfo.contentChecksumFlag*BFSize); return ((BHSize + 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 MEM_INIT(&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(LZ4F_cctx* cctx, void* dstBuffer, size_t dstCapacity, const void* srcBuffer, size_t srcSize, const LZ4F_CDict* cdict, const LZ4F_preferences_t* preferencesPtr) { LZ4F_preferences_t prefs; LZ4F_compressOptions_t options; BYTE* const dstStart = (BYTE*) dstBuffer; BYTE* dstPtr = dstStart; BYTE* const dstEnd = dstStart + dstCapacity; if (preferencesPtr!=NULL) prefs = *preferencesPtr; else MEM_INIT(&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 */ MEM_INIT(&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(cctx, dstBuffer, dstCapacity, cdict, &prefs); /* write header */ if (LZ4F_isError(headerSize)) return headerSize; dstPtr += headerSize; /* header size */ } assert(dstEnd >= dstPtr); { size_t const cSize = LZ4F_compressUpdate(cctx, dstPtr, (size_t)(dstEnd-dstPtr), srcBuffer, srcSize, &options); if (LZ4F_isError(cSize)) return cSize; dstPtr += cSize; } assert(dstEnd >= dstPtr); { size_t const tailSize = LZ4F_compressEnd(cctx, dstPtr, (size_t)(dstEnd-dstPtr), &options); /* flush last block, and generate suffix */ if (LZ4F_isError(tailSize)) return tailSize; dstPtr += tailSize; } assert(dstEnd >= dstStart); return (size_t)(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) { size_t result; #if (LZ4F_HEAPMODE) LZ4F_cctx_t *cctxPtr; result = LZ4F_createCompressionContext(&cctxPtr, LZ4F_VERSION); if (LZ4F_isError(result)) return result; #else LZ4F_cctx_t cctx; LZ4_stream_t lz4ctx; LZ4F_cctx_t *cctxPtr = &cctx; DEBUGLOG(4, "LZ4F_compressFrame"); MEM_INIT(&cctx, 0, sizeof(cctx)); cctx.version = LZ4F_VERSION; cctx.maxBufferSize = 5 MB; /* mess with real buffer size to prevent dynamic allocation; works only because autoflush==1 & stableSrc==1 */ if (preferencesPtr == NULL || preferencesPtr->compressionLevel < LZ4HC_CLEVEL_MIN) { LZ4_initStream(&lz4ctx, sizeof(lz4ctx)); cctxPtr->lz4CtxPtr = &lz4ctx; cctxPtr->lz4CtxAlloc = 1; cctxPtr->lz4CtxState = 1; } #endif result = LZ4F_compressFrame_usingCDict(cctxPtr, dstBuffer, dstCapacity, srcBuffer, srcSize, NULL, preferencesPtr); #if (LZ4F_HEAPMODE) LZ4F_freeCompressionContext(cctxPtr); #else if (preferencesPtr != NULL && preferencesPtr->compressionLevel >= LZ4HC_CLEVEL_MIN) { FREEMEM(cctxPtr->lz4CtxPtr); } #endif return result; } /*-*************************************************** * 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*) ALLOC(sizeof(*cdict)); DEBUGLOG(4, "LZ4F_createCDict"); if (!cdict) return NULL; if (dictSize > 64 KB) { dictStart += dictSize - 64 KB; dictSize = 64 KB; } cdict->dictContent = ALLOC(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_loadDict (cdict->fastCtx, (const char*)cdict->dictContent, (int)dictSize); LZ4_setCompressionLevel(cdict->HCCtx, LZ4HC_CLEVEL_DEFAULT); LZ4_loadDictHC(cdict->HCCtx, (const char*)cdict->dictContent, (int)dictSize); return cdict; } void LZ4F_freeCDict(LZ4F_CDict* cdict) { if (cdict==NULL) return; /* support free on NULL */ FREEMEM(cdict->dictContent); LZ4_freeStream(cdict->fastCtx); LZ4_freeStreamHC(cdict->HCCtx); FREEMEM(cdict); } /*-********************************* * 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*)ALLOC_AND_ZERO(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; } /** * This function prepares the internal LZ4(HC) stream for a new compression, * resetting the context and attaching the dictionary, if there is one. * * It needs to be called at the beginning of each independent compression * stream (i.e., at the beginning of a frame in blockLinked mode, or at the * beginning of each block in blockIndependent mode). */ static void LZ4F_initStream(void* ctx, const LZ4F_CDict* cdict, int level, LZ4F_blockMode_t blockMode) { if (level < LZ4HC_CLEVEL_MIN) { if (cdict != NULL || blockMode == LZ4F_blockLinked) { /* In these cases, we will call LZ4_compress_fast_continue(), * which needs an already reset context. Otherwise, we'll call a * one-shot API. The non-continued APIs internally perform their own * resets at the beginning of their calls, where they know what * tableType they need the context to be in. So in that case this * would be misguided / wasted work. */ LZ4_resetStream_fast((LZ4_stream_t*)ctx); } LZ4_attach_dictionary((LZ4_stream_t *)ctx, cdict ? cdict->fastCtx : NULL); } else { LZ4_resetStreamHC_fast((LZ4_streamHC_t*)ctx, level); LZ4_attach_HC_dictionary((LZ4_streamHC_t *)ctx, cdict ? cdict->HCCtx : NULL); } } /*! 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); MEM_INIT(&prefNull, 0, sizeof(prefNull)); if (preferencesPtr == NULL) preferencesPtr = &prefNull; cctxPtr->prefs = *preferencesPtr; /* Ctx Management */ { U16 const ctxTypeID = (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN) ? 1 : 2; if (cctxPtr->lz4CtxAlloc < ctxTypeID) { FREEMEM(cctxPtr->lz4CtxPtr); if (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN) { cctxPtr->lz4CtxPtr = LZ4_createStream(); } else { cctxPtr->lz4CtxPtr = LZ4_createStreamHC(); } if (cctxPtr->lz4CtxPtr == NULL) return err0r(LZ4F_ERROR_allocation_failed); cctxPtr->lz4CtxAlloc = ctxTypeID; cctxPtr->lz4CtxState = ctxTypeID; } else if (cctxPtr->lz4CtxState != ctxTypeID) { /* otherwise, a sufficient buffer is allocated, but we need to * reset it to the correct context type */ if (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN) { LZ4_initStream((LZ4_stream_t *) cctxPtr->lz4CtxPtr, sizeof (LZ4_stream_t)); } else { LZ4_initStreamHC((LZ4_streamHC_t *) cctxPtr->lz4CtxPtr, sizeof(LZ4_streamHC_t)); LZ4_setCompressionLevel((LZ4_streamHC_t *) cctxPtr->lz4CtxPtr, cctxPtr->prefs.compressionLevel); } cctxPtr->lz4CtxState = 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*)ALLOC_AND_ZERO(requiredBuffSize); if (cctxPtr->tmpBuff == NULL) return err0r(LZ4F_ERROR_allocation_failed); cctxPtr->maxBufferSize = requiredBuffSize; } } cctxPtr->tmpIn = cctxPtr->tmpBuff; cctxPtr->tmpInSize = 0; (void)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 */ LZ4F_initStream(cctxPtr->lz4CtxPtr, cdict, cctxPtr->prefs.compressionLevel, LZ4F_blockLinked); } if (preferencesPtr->compressionLevel >= LZ4HC_CLEVEL_MIN) { LZ4_favorDecompressionSpeed((LZ4_streamHC_t*)cctxPtr->lz4CtxPtr, (int)preferencesPtr->favorDecSpeed); } /* 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) + ((unsigned)(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, (size_t)(dstPtr - headerStart)); dstPtr++; cctxPtr->cStage = 1; /* header written, now request input data block */ return (size_t)(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 optional checksum. * assumption : dst buffer capacity is >= BHSize + srcSize + crcSize */ 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+BHSize), (int)(srcSize), (int)(srcSize-1), level, cdict); if (cSize == 0) { /* compression failed */ cSize = (U32)srcSize; LZ4F_writeLE32(cSizePtr, cSize | LZ4F_BLOCKUNCOMPRESSED_FLAG); memcpy(cSizePtr+BHSize, src, srcSize); } else { LZ4F_writeLE32(cSizePtr, cSize); } if (crcFlag) { U32 const crc32 = XXH32(cSizePtr+BHSize, cSize, 0); /* checksum of compressed data */ LZ4F_writeLE32(cSizePtr+BHSize+cSize, crc32); } return BHSize + cSize + ((U32)crcFlag)*BFSize; } 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 < 0) ? -level + 1 : 1; LZ4F_initStream(ctx, cdict, level, LZ4F_blockIndependent); if (cdict) { return LZ4_compress_fast_continue((LZ4_stream_t*)ctx, src, dst, srcSize, dstCapacity, acceleration); } else { return LZ4_compress_fast_extState_fastReset(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 < 0) ? -level + 1 : 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) { LZ4F_initStream(ctx, cdict, level, LZ4F_blockIndependent); if (cdict) { return LZ4_compress_HC_continue((LZ4_streamHC_t*)ctx, src, dst, srcSize, dstCapacity); } return LZ4_compress_HC_extStateHC_fastReset(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); DEBUGLOG(4, "LZ4F_compressUpdate (srcSize=%zu)", srcSize); 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); MEM_INIT(&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, (size_t)(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 = (size_t)(srcEnd - srcPtr); memcpy(cctxPtr->tmpIn, srcPtr, sizeToCopy); cctxPtr->tmpInSize = sizeToCopy; } if (cctxPtr->prefs.frameInfo.contentChecksumFlag == LZ4F_contentChecksumEnabled) (void)XXH32_update(&(cctxPtr->xxh), srcBuffer, srcSize); cctxPtr->totalInSize += srcSize; return (size_t)(dstPtr - dstStart); } /*! LZ4F_flush() : * When compressed data must be sent immediately, without waiting for a block to be filled, * invoke LZ4_flush(), which will immediately compress any remaining data stored within LZ4F_cctx. * 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 LZ4F_cctx. * The function outputs an error code if it fails (can be tested using LZ4F_isError()) * LZ4F_compressOptions_t* is optional. NULL is a valid 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 + BHSize + BFSize)) return err0r(LZ4F_ERROR_dstMaxSize_tooSmall); (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); assert(((void)"flush overflows dstBuffer!", (size_t)(dstPtr - dstStart) < dstCapacity)); 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 const realDictSize = LZ4F_localSaveDict(cctxPtr); cctxPtr->tmpIn = cctxPtr->tmpBuff + realDictSize; } return (size_t)(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 an (optional) checksum. * LZ4F_compressOptions_t structure is optional : you can provide NULL as argument. * @return: the number of bytes written into dstBuffer (necessarily >= 4 (endMark size)) * or an error code if it fails (can be tested using LZ4F_isError()) * The context can then be used again to compress a new frame, starting with LZ4F_compressBegin(). */ size_t LZ4F_compressEnd(LZ4F_cctx* cctxPtr, void* dstBuffer, size_t dstCapacity, const LZ4F_compressOptions_t* compressOptionsPtr) { BYTE* const dstStart = (BYTE*)dstBuffer; BYTE* dstPtr = dstStart; size_t const flushSize = LZ4F_flush(cctxPtr, dstBuffer, dstCapacity, compressOptionsPtr); if (LZ4F_isError(flushSize)) return flushSize; dstPtr += flushSize; assert(flushSize <= dstCapacity); dstCapacity -= flushSize; if (dstCapacity < 4) return err0r(LZ4F_ERROR_dstMaxSize_tooSmall); LZ4F_writeLE32(dstPtr, 0); dstPtr += 4; /* endMark */ if (cctxPtr->prefs.frameInfo.contentChecksumFlag == LZ4F_contentChecksumEnabled) { U32 const xxh = XXH32_digest(&(cctxPtr->xxh)); if (dstCapacity < 8) return err0r(LZ4F_ERROR_dstMaxSize_tooSmall); 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 (size_t)(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*)ALLOC_AND_ZERO(sizeof(LZ4F_dctx)); if (dctx==NULL) return err0r(LZ4F_ERROR_GENERIC); dctx->version = versionNumber; *LZ4F_decompressionContextPtr = dctx; return LZ4F_OK_NoError; } LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* dctx) { LZ4F_errorCode_t result = LZ4F_OK_NoError; if (dctx != NULL) { /* can accept NULL input, like free() */ result = (LZ4F_errorCode_t)dctx->dStage; FREEMEM(dctx->tmpIn); FREEMEM(dctx->tmpOutBuffer); FREEMEM(dctx); } return result; } /*==--- Streaming Decompression operations ---==*/ void LZ4F_resetDecompressionContext(LZ4F_dctx* dctx) { dctx->dStage = dstage_getFrameHeader; dctx->dict = NULL; dctx->dictSize = 0; } /*! LZ4F_headerSize() : * @return : size of frame header * or an error code, which can be tested using LZ4F_isError() */ static size_t LZ4F_headerSize(const void* src, size_t srcSize) { /* minimal srcSize to determine header size */ if (srcSize < 5) return err0r(LZ4F_ERROR_frameHeader_incomplete); /* special case : skippable frames */ if ((LZ4F_readLE32(src) & 0xFFFFFFF0U) == LZ4F_MAGIC_SKIPPABLE_START) return 8; /* control magic number */ if (LZ4F_readLE32(src) != LZ4F_MAGICNUMBER) return err0r(LZ4F_ERROR_frameType_unknown); /* Frame Header Size */ { BYTE const FLG = ((const BYTE*)src)[4]; U32 const contentSizeFlag = (FLG>>3) & _1BIT; U32 const dictIDFlag = FLG & _1BIT; return minFHSize + (contentSizeFlag*8) + (dictIDFlag*4); } } /*! LZ4F_decodeHeader() : * input : `src` points at the **beginning of the frame** * output : set internal values of dctx, such as * dctx->frameInfo and dctx->dStage. * Also allocates internal buffers. * @return : nb Bytes read from src (necessarily <= srcSize) * or an error code (testable with LZ4F_isError()) */ static size_t LZ4F_decodeHeader(LZ4F_dctx* dctx, const void* src, size_t srcSize) { unsigned blockMode, blockChecksumFlag, contentSizeFlag, contentChecksumFlag, dictIDFlag, blockSizeID; size_t frameHeaderSize; const BYTE* srcPtr = (const BYTE*)src; /* need to decode header to get frameInfo */ if (srcSize < minFHSize) return err0r(LZ4F_ERROR_frameHeader_incomplete); /* minimal frame header size */ MEM_INIT(&(dctx->frameInfo), 0, sizeof(dctx->frameInfo)); /* special case : skippable frames */ if ((LZ4F_readLE32(srcPtr) & 0xFFFFFFF0U) == LZ4F_MAGIC_SKIPPABLE_START) { dctx->frameInfo.frameType = LZ4F_skippableFrame; if (src == (void*)(dctx->header)) { dctx->tmpInSize = srcSize; dctx->tmpInTarget = 8; dctx->dStage = dstage_storeSFrameSize; return srcSize; } else { dctx->dStage = dstage_getSFrameSize; return 4; } } /* control magic number */ if (LZ4F_readLE32(srcPtr) != LZ4F_MAGICNUMBER) return err0r(LZ4F_ERROR_frameType_unknown); dctx->frameInfo.frameType = LZ4F_frame; /* Flags */ { U32 const FLG = srcPtr[4]; U32 const version = (FLG>>6) & _2BITS; blockChecksumFlag = (FLG>>4) & _1BIT; blockMode = (FLG>>5) & _1BIT; contentSizeFlag = (FLG>>3) & _1BIT; contentChecksumFlag = (FLG>>2) & _1BIT; dictIDFlag = FLG & _1BIT; /* validate */ if (((FLG>>1)&_1BIT) != 0) return err0r(LZ4F_ERROR_reservedFlag_set); /* Reserved bit */ if (version != 1) return err0r(LZ4F_ERROR_headerVersion_wrong); /* Version Number, only supported value */ } /* Frame Header Size */ frameHeaderSize = minFHSize + (contentSizeFlag*8) + (dictIDFlag*4); if (srcSize < frameHeaderSize) { /* not enough input to fully decode frame header */ if (srcPtr != dctx->header) memcpy(dctx->header, srcPtr, srcSize); dctx->tmpInSize = srcSize; dctx->tmpInTarget = frameHeaderSize; dctx->dStage = dstage_storeFrameHeader; return srcSize; } { U32 const BD = srcPtr[5]; blockSizeID = (BD>>4) & _3BITS; /* validate */ if (((BD>>7)&_1BIT) != 0) return err0r(LZ4F_ERROR_reservedFlag_set); /* Reserved bit */ if (blockSizeID < 4) return err0r(LZ4F_ERROR_maxBlockSize_invalid); /* 4-7 only supported values for the time being */ if (((BD>>0)&_4BITS) != 0) return err0r(LZ4F_ERROR_reservedFlag_set); /* Reserved bits */ } /* check header */ { BYTE const HC = LZ4F_headerChecksum(srcPtr+4, frameHeaderSize-5); if (HC != srcPtr[frameHeaderSize-1]) return err0r(LZ4F_ERROR_headerChecksum_invalid); } /* save */ dctx->frameInfo.blockMode = (LZ4F_blockMode_t)blockMode; dctx->frameInfo.blockChecksumFlag = (LZ4F_blockChecksum_t)blockChecksumFlag; dctx->frameInfo.contentChecksumFlag = (LZ4F_contentChecksum_t)contentChecksumFlag; dctx->frameInfo.blockSizeID = (LZ4F_blockSizeID_t)blockSizeID; dctx->maxBlockSize = LZ4F_getBlockSize(blockSizeID); if (contentSizeFlag) dctx->frameRemainingSize = dctx->frameInfo.contentSize = LZ4F_readLE64(srcPtr+6); if (dictIDFlag) dctx->frameInfo.dictID = LZ4F_readLE32(srcPtr + frameHeaderSize - 5); dctx->dStage = dstage_init; return frameHeaderSize; } /*! LZ4F_getFrameInfo() : * This function extracts frame parameters (max blockSize, frame checksum, etc.). * Usage is optional. Objective is to provide relevant information for allocation purposes. * This function works in 2 situations : * - At the beginning of a new frame, in which case it will decode this information from `srcBuffer`, and start the decoding process. * Amount of input data provided must be large enough to successfully decode the frame header. * A header size is variable, but is guaranteed to be <= LZ4F_HEADER_SIZE_MAX bytes. It's possible to provide more input data than this minimum. * - After decoding has been started. In which case, no input is read, frame parameters are extracted from dctx. * The number of bytes consumed from srcBuffer will be updated within *srcSizePtr (necessarily <= original value). * 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); } else { size_t decodeResult; size_t const hSize = LZ4F_headerSize(srcBuffer, *srcSizePtr); if (LZ4F_isError(hSize)) { *srcSizePtr=0; return hSize; } if (*srcSizePtr < hSize) { *srcSizePtr=0; return err0r(LZ4F_ERROR_frameHeader_incomplete); } decodeResult = LZ4F_decodeHeader(dctx, srcBuffer, hSize); if (LZ4F_isError(decodeResult)) { *srcSizePtr = 0; } else { *srcSizePtr = decodeResult; decodeResult = BHSize; /* block header size */ } *frameInfoPtr = dctx->frameInfo; return decodeResult; } } } /* LZ4F_updateDict() : * only used for LZ4F_blockLinked mode */ static void LZ4F_updateDict(LZ4F_dctx* dctx, const BYTE* dstPtr, size_t dstSize, const BYTE* dstBufferStart, unsigned withinTmp) { if (dctx->dictSize==0) dctx->dict = (const BYTE*)dstPtr; /* priority to dictionary continuity */ if (dctx->dict + dctx->dictSize == dstPtr) { /* dictionary continuity, directly within dstBuffer */ dctx->dictSize += dstSize; return; } assert(dstPtr >= dstBufferStart); if ((size_t)(dstPtr - dstBufferStart) + dstSize >= 64 KB) { /* history in dstBuffer becomes large enough to become dictionary */ dctx->dict = (const BYTE*)dstBufferStart; dctx->dictSize = (size_t)(dstPtr - dstBufferStart) + dstSize; return; } assert(dstSize < 64 KB); /* if dstSize >= 64 KB, dictionary would be set into dstBuffer directly */ /* dstBuffer does not contain whole useful history (64 KB), so it must be saved within tmpOut */ if ((withinTmp) && (dctx->dict == dctx->tmpOutBuffer)) { /* continue history within tmpOutBuffer */ /* withinTmp expectation : content of [dstPtr,dstSize] is same as [dict+dictSize,dstSize], so we just extend it */ assert(dctx->dict + dctx->dictSize == dctx->tmpOut + dctx->tmpOutStart); dctx->dictSize += dstSize; return; } if (withinTmp) { /* copy relevant dict portion in front of tmpOut within tmpOutBuffer */ size_t const preserveSize = (size_t)(dctx->tmpOut - dctx->tmpOutBuffer); size_t copySize = 64 KB - dctx->tmpOutSize; const BYTE* const oldDictEnd = dctx->dict + dctx->dictSize - dctx->tmpOutStart; if (dctx->tmpOutSize > 64 KB) copySize = 0; if (copySize > preserveSize) copySize = preserveSize; memcpy(dctx->tmpOutBuffer + preserveSize - copySize, oldDictEnd - copySize, copySize); dctx->dict = dctx->tmpOutBuffer; dctx->dictSize = preserveSize + dctx->tmpOutStart + dstSize; return; } if (dctx->dict == dctx->tmpOutBuffer) { /* copy dst into tmp to complete dict */ if (dctx->dictSize + dstSize > dctx->maxBufferSize) { /* tmp buffer not large enough */ size_t const preserveSize = 64 KB - dstSize; memcpy(dctx->tmpOutBuffer, dctx->dict + dctx->dictSize - preserveSize, preserveSize); dctx->dictSize = preserveSize; } memcpy(dctx->tmpOutBuffer + dctx->dictSize, dstPtr, dstSize); dctx->dictSize += dstSize; return; } /* join dict & dest into tmp */ { size_t preserveSize = 64 KB - dstSize; if (preserveSize > dctx->dictSize) preserveSize = dctx->dictSize; memcpy(dctx->tmpOutBuffer, dctx->dict + dctx->dictSize - preserveSize, preserveSize); memcpy(dctx->tmpOutBuffer + preserveSize, dstPtr, dstSize); dctx->dict = dctx->tmpOutBuffer; dctx->dictSize = preserveSize + dstSize; } } /*! LZ4F_decompress() : * Call this function repetitively to regenerate compressed data in srcBuffer. * 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 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; const BYTE* srcPtr = srcStart; BYTE* const dstStart = (BYTE*)dstBuffer; BYTE* const dstEnd = dstStart + *dstSizePtr; BYTE* dstPtr = dstStart; const BYTE* selectedIn = NULL; unsigned doAnotherStage = 1; size_t nextSrcSizeHint = 1; MEM_INIT(&optionsNull, 0, sizeof(optionsNull)); if (decompressOptionsPtr==NULL) decompressOptionsPtr = &optionsNull; *srcSizePtr = 0; *dstSizePtr = 0; /* behaves as a state machine */ while (doAnotherStage) { switch(dctx->dStage) { case dstage_getFrameHeader: if ((size_t)(srcEnd-srcPtr) >= maxFHSize) { /* enough to decode - shortcut */ size_t const hSize = LZ4F_decodeHeader(dctx, srcPtr, (size_t)(srcEnd-srcPtr)); /* will update dStage appropriately */ if (LZ4F_isError(hSize)) return hSize; srcPtr += hSize; break; } dctx->tmpInSize = 0; if (srcEnd-srcPtr == 0) return minFHSize; /* 0-size input */ dctx->tmpInTarget = minFHSize; /* minimum size to decode header */ dctx->dStage = dstage_storeFrameHeader; /* fall-through */ case dstage_storeFrameHeader: { size_t const sizeToCopy = MIN(dctx->tmpInTarget - dctx->tmpInSize, (size_t)(srcEnd - srcPtr)); memcpy(dctx->header + dctx->tmpInSize, srcPtr, sizeToCopy); dctx->tmpInSize += sizeToCopy; srcPtr += sizeToCopy; } if (dctx->tmpInSize < dctx->tmpInTarget) { nextSrcSizeHint = (dctx->tmpInTarget - dctx->tmpInSize) + BHSize; /* rest of header + nextBlockHeader */ doAnotherStage = 0; /* not enough src data, ask for some more */ break; } { size_t const hSize = LZ4F_decodeHeader(dctx, dctx->header, dctx->tmpInTarget); /* will update dStage appropriately */ if (LZ4F_isError(hSize)) return hSize; } break; case dstage_init: if (dctx->frameInfo.contentChecksumFlag) (void)XXH32_reset(&(dctx->xxh), 0); /* internal buffers allocation */ { size_t const bufferNeeded = dctx->maxBlockSize + ((dctx->frameInfo.blockMode==LZ4F_blockLinked) * 128 KB); if (bufferNeeded > dctx->maxBufferSize) { /* tmp buffers too small */ dctx->maxBufferSize = 0; /* ensure allocation will be re-attempted on next entry*/ FREEMEM(dctx->tmpIn); dctx->tmpIn = (BYTE*)ALLOC(dctx->maxBlockSize + 4 /* block checksum */); if (dctx->tmpIn == NULL) return err0r(LZ4F_ERROR_allocation_failed); FREEMEM(dctx->tmpOutBuffer); dctx->tmpOutBuffer= (BYTE*)ALLOC(bufferNeeded); if (dctx->tmpOutBuffer== NULL) return err0r(LZ4F_ERROR_allocation_failed); dctx->maxBufferSize = bufferNeeded; } } dctx->tmpInSize = 0; dctx->tmpInTarget = 0; dctx->tmpOut = dctx->tmpOutBuffer; dctx->tmpOutStart = 0; dctx->tmpOutSize = 0; dctx->dStage = dstage_getBlockHeader; /* fall-through */ case dstage_getBlockHeader: if ((size_t)(srcEnd - srcPtr) >= BHSize) { selectedIn = srcPtr; srcPtr += BHSize; } else { /* not enough input to read cBlockSize field */ dctx->tmpInSize = 0; dctx->dStage = dstage_storeBlockHeader; } if (dctx->dStage == dstage_storeBlockHeader) /* can be skipped */ case dstage_storeBlockHeader: { size_t const remainingInput = (size_t)(srcEnd - srcPtr); size_t const wantedData = BHSize - dctx->tmpInSize; size_t const sizeToCopy = MIN(wantedData, remainingInput); memcpy(dctx->tmpIn + dctx->tmpInSize, srcPtr, sizeToCopy); srcPtr += sizeToCopy; dctx->tmpInSize += sizeToCopy; if (dctx->tmpInSize < BHSize) { /* not enough input for cBlockSize */ nextSrcSizeHint = BHSize - dctx->tmpInSize; doAnotherStage = 0; break; } selectedIn = dctx->tmpIn; } /* if (dctx->dStage == dstage_storeBlockHeader) */ /* decode block header */ { size_t const nextCBlockSize = LZ4F_readLE32(selectedIn) & 0x7FFFFFFFU; size_t const crcSize = dctx->frameInfo.blockChecksumFlag * BFSize; if (nextCBlockSize==0) { /* frameEnd signal, no more block */ dctx->dStage = dstage_getSuffix; break; } if (nextCBlockSize > dctx->maxBlockSize) return err0r(LZ4F_ERROR_maxBlockSize_invalid); if (LZ4F_readLE32(selectedIn) & LZ4F_BLOCKUNCOMPRESSED_FLAG) { /* next block is uncompressed */ dctx->tmpInTarget = nextCBlockSize; if (dctx->frameInfo.blockChecksumFlag) { (void)XXH32_reset(&dctx->blockChecksum, 0); } dctx->dStage = dstage_copyDirect; break; } /* next block is a compressed block */ dctx->tmpInTarget = nextCBlockSize + crcSize; dctx->dStage = dstage_getCBlock; if (dstPtr==dstEnd) { nextSrcSizeHint = BHSize + nextCBlockSize + crcSize; doAnotherStage = 0; } break; } case dstage_copyDirect: /* uncompressed block */ { size_t const minBuffSize = MIN((size_t)(srcEnd-srcPtr), (size_t)(dstEnd-dstPtr)); size_t const sizeToCopy = MIN(dctx->tmpInTarget, minBuffSize); memcpy(dstPtr, srcPtr, sizeToCopy); if (dctx->frameInfo.blockChecksumFlag) { (void)XXH32_update(&dctx->blockChecksum, srcPtr, sizeToCopy); } if (dctx->frameInfo.contentChecksumFlag) (void)XXH32_update(&dctx->xxh, srcPtr, sizeToCopy); if (dctx->frameInfo.contentSize) dctx->frameRemainingSize -= sizeToCopy; /* history management (linked blocks only)*/ if (dctx->frameInfo.blockMode == LZ4F_blockLinked) LZ4F_updateDict(dctx, dstPtr, sizeToCopy, dstStart, 0); srcPtr += sizeToCopy; dstPtr += sizeToCopy; if (sizeToCopy == dctx->tmpInTarget) { /* all done */ if (dctx->frameInfo.blockChecksumFlag) { dctx->tmpInSize = 0; dctx->dStage = dstage_getBlockChecksum; } else dctx->dStage = dstage_getBlockHeader; /* new block */ break; } dctx->tmpInTarget -= sizeToCopy; /* need to copy more */ nextSrcSizeHint = dctx->tmpInTarget + + dctx->frameInfo.blockChecksumFlag * 4 /* size for block checksum */ + BHSize /* next header size */; doAnotherStage = 0; break; } /* check block checksum for recently transferred uncompressed block */ case dstage_getBlockChecksum: { const void* crcSrc; if ((srcEnd-srcPtr >= 4) && (dctx->tmpInSize==0)) { crcSrc = srcPtr; srcPtr += 4; } else { size_t const stillToCopy = 4 - dctx->tmpInSize; size_t const sizeToCopy = MIN(stillToCopy, (size_t)(srcEnd-srcPtr)); memcpy(dctx->header + dctx->tmpInSize, srcPtr, sizeToCopy); dctx->tmpInSize += sizeToCopy; srcPtr += sizeToCopy; if (dctx->tmpInSize < 4) { /* all input consumed */ doAnotherStage = 0; break; } crcSrc = dctx->header; } { U32 const readCRC = LZ4F_readLE32(crcSrc); U32 const calcCRC = XXH32_digest(&dctx->blockChecksum); if (readCRC != calcCRC) return err0r(LZ4F_ERROR_blockChecksum_invalid); } } dctx->dStage = dstage_getBlockHeader; /* new block */ break; case dstage_getCBlock: if ((size_t)(srcEnd-srcPtr) < dctx->tmpInTarget) { dctx->tmpInSize = 0; dctx->dStage = dstage_storeCBlock; break; } /* input large enough to read full block directly */ selectedIn = srcPtr; srcPtr += dctx->tmpInTarget; if (0) /* jump over next block */ case dstage_storeCBlock: { size_t const wantedData = dctx->tmpInTarget - dctx->tmpInSize; size_t const inputLeft = (size_t)(srcEnd-srcPtr); size_t const sizeToCopy = MIN(wantedData, inputLeft); memcpy(dctx->tmpIn + dctx->tmpInSize, srcPtr, sizeToCopy); dctx->tmpInSize += sizeToCopy; srcPtr += sizeToCopy; if (dctx->tmpInSize < dctx->tmpInTarget) { /* need more input */ nextSrcSizeHint = (dctx->tmpInTarget - dctx->tmpInSize) + dctx->frameInfo.blockChecksumFlag * 4 /* size for block checksum */ + BHSize /* next header size */; doAnotherStage = 0; break; } selectedIn = dctx->tmpIn; } /* At this stage, input is large enough to decode a block */ if (dctx->frameInfo.blockChecksumFlag) { 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) { const char* dict = (const char*)dctx->dict; size_t dictSize = dctx->dictSize; int decodedSize; if (dict && dictSize > 1 GB) { /* the dictSize param is an int, avoid truncation / sign issues */ dict += dictSize - 64 KB; dictSize = 64 KB; } /* enough capacity in `dst` to decompress directly there */ decodedSize = LZ4_decompress_safe_usingDict( (const char*)selectedIn, (char*)dstPtr, (int)dctx->tmpInTarget, (int)dctx->maxBlockSize, dict, (int)dictSize); if (decodedSize < 0) return err0r(LZ4F_ERROR_GENERIC); /* decompression failed */ if (dctx->frameInfo.contentChecksumFlag) XXH32_update(&(dctx->xxh), dstPtr, (size_t)decodedSize); if (dctx->frameInfo.contentSize) dctx->frameRemainingSize -= (size_t)decodedSize; /* dictionary management */ if (dctx->frameInfo.blockMode==LZ4F_blockLinked) LZ4F_updateDict(dctx, dstPtr, (size_t)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 */ { const char* dict = (const char*)dctx->dict; size_t dictSize = dctx->dictSize; int decodedSize; if (dict && dictSize > 1 GB) { /* the dictSize param is an int, avoid truncation / sign issues */ dict += dictSize - 64 KB; dictSize = 64 KB; } decodedSize = LZ4_decompress_safe_usingDict( (const char*)selectedIn, (char*)dctx->tmpOut, (int)dctx->tmpInTarget, (int)dctx->maxBlockSize, dict, (int)dictSize); if (decodedSize < 0) /* decompression failed */ return err0r(LZ4F_ERROR_decompressionFailed); if (dctx->frameInfo.contentChecksumFlag) XXH32_update(&(dctx->xxh), dctx->tmpOut, (size_t)decodedSize); if (dctx->frameInfo.contentSize) dctx->frameRemainingSize -= (size_t)decodedSize; dctx->tmpOutSize = (size_t)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 /*withinTmp*/); dctx->tmpOutStart += sizeToCopy; dstPtr += sizeToCopy; if (dctx->tmpOutStart == dctx->tmpOutSize) { /* all flushed */ dctx->dStage = dstage_getBlockHeader; /* get next block */ break; } /* could not flush everything : stop there, just request a block header */ doAnotherStage = 0; nextSrcSizeHint = BHSize; 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 { selectedIn = srcPtr; srcPtr += 4; } if (dctx->dStage == dstage_storeSuffix) /* can be skipped */ case dstage_storeSuffix: { size_t const remainingInput = (size_t)(srcEnd - srcPtr); size_t const wantedData = 4 - dctx->tmpInSize; size_t const sizeToCopy = MIN(wantedData, remainingInput); memcpy(dctx->tmpIn + dctx->tmpInSize, srcPtr, sizeToCopy); srcPtr += sizeToCopy; dctx->tmpInSize += sizeToCopy; if (dctx->tmpInSize < 4) { /* not enough input to read complete suffix */ nextSrcSizeHint = 4 - dctx->tmpInSize; doAnotherStage=0; break; } selectedIn = dctx->tmpIn; } /* if (dctx->dStage == dstage_storeSuffix) */ /* case dstage_checkSuffix: */ /* no direct entry, avoid initialization risks */ { U32 const readCRC = LZ4F_readLE32(selectedIn); U32 const resultCRC = XXH32_digest(&(dctx->xxh)); if (readCRC != resultCRC) return err0r(LZ4F_ERROR_contentChecksum_invalid); nextSrcSizeHint = 0; LZ4F_resetDecompressionContext(dctx); doAnotherStage = 0; break; } case dstage_getSFrameSize: if ((srcEnd - srcPtr) >= 4) { selectedIn = srcPtr; srcPtr += 4; } else { /* not enough input to read cBlockSize field */ dctx->tmpInSize = 4; dctx->tmpInTarget = 8; dctx->dStage = dstage_storeSFrameSize; } if (dctx->dStage == dstage_storeSFrameSize) case dstage_storeSFrameSize: { size_t const sizeToCopy = MIN(dctx->tmpInTarget - dctx->tmpInSize, (size_t)(srcEnd - srcPtr) ); memcpy(dctx->header + dctx->tmpInSize, srcPtr, sizeToCopy); srcPtr += sizeToCopy; dctx->tmpInSize += sizeToCopy; if (dctx->tmpInSize < dctx->tmpInTarget) { /* not enough input to get full sBlockSize; wait for more */ nextSrcSizeHint = dctx->tmpInTarget - dctx->tmpInSize; doAnotherStage = 0; break; } selectedIn = dctx->header + 4; } /* if (dctx->dStage == dstage_storeSFrameSize) */ /* case dstage_decodeSFrameSize: */ /* no direct entry */ { size_t const SFrameSize = LZ4F_readLE32(selectedIn); dctx->frameInfo.contentSize = SFrameSize; dctx->tmpInTarget = SFrameSize; dctx->dStage = dstage_skipSkippable; break; } case dstage_skipSkippable: { size_t const skipSize = MIN(dctx->tmpInTarget, (size_t)(srcEnd-srcPtr)); srcPtr += skipSize; dctx->tmpInTarget -= skipSize; doAnotherStage = 0; nextSrcSizeHint = dctx->tmpInTarget; if (nextSrcSizeHint) break; /* still more to skip */ /* frame fully skipped : prepare context for a new frame */ LZ4F_resetDecompressionContext(dctx); break; } } /* switch (dctx->dStage) */ } /* while (doAnotherStage) */ /* preserve history within tmp whenever necessary */ LZ4F_STATIC_ASSERT((unsigned)dstage_init == 2); if ( (dctx->frameInfo.blockMode==LZ4F_blockLinked) /* next block will use up to 64KB from previous ones */ && (dctx->dict != dctx->tmpOutBuffer) /* dictionary is not already within tmp */ && (!decompressOptionsPtr->stableDst) /* cannot rely on dst data to remain there for next call */ && ((unsigned)(dctx->dStage)-2 < (unsigned)(dstage_getSuffix)-2) ) /* valid stages : [init ... getSuffix[ */ { if (dctx->dStage == dstage_flushOut) { size_t const preserveSize = (size_t)(dctx->tmpOut - dctx->tmpOutBuffer); size_t copySize = 64 KB - dctx->tmpOutSize; const BYTE* oldDictEnd = dctx->dict + dctx->dictSize - dctx->tmpOutStart; if (dctx->tmpOutSize > 64 KB) copySize = 0; if (copySize > preserveSize) copySize = preserveSize; if (copySize > 0) memcpy(dctx->tmpOutBuffer + preserveSize - copySize, oldDictEnd - copySize, copySize); dctx->dict = dctx->tmpOutBuffer; dctx->dictSize = preserveSize + dctx->tmpOutStart; } else { const BYTE* const oldDictEnd = dctx->dict + dctx->dictSize; size_t const newDictSize = MIN(dctx->dictSize, 64 KB); if (newDictSize > 0) memcpy(dctx->tmpOutBuffer, oldDictEnd - newDictSize, newDictSize); dctx->dict = dctx->tmpOutBuffer; dctx->dictSize = newDictSize; dctx->tmpOut = dctx->tmpOutBuffer + newDictSize; } } *srcSizePtr = (size_t)(srcPtr - srcStart); *dstSizePtr = (size_t)(dstPtr - dstStart); return nextSrcSizeHint; } /*! LZ4F_decompress_usingDict() : * Same as LZ4F_decompress(), using a predefined dictionary. * Dictionary is used "in place", without any preprocessing. * It must remain accessible throughout the entire frame decoding. */ size_t LZ4F_decompress_usingDict(LZ4F_dctx* dctx, void* dstBuffer, size_t* dstSizePtr, const void* srcBuffer, size_t* srcSizePtr, const void* dict, size_t dictSize, const LZ4F_decompressOptions_t* decompressOptionsPtr) { if (dctx->dStage <= dstage_init) { dctx->dict = (const BYTE*)dict; dctx->dictSize = dictSize; } return LZ4F_decompress(dctx, dstBuffer, dstSizePtr, srcBuffer, srcSizePtr, decompressOptionsPtr); }