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Diffstat (limited to 'contrib/zstd/zstd_decompress.c')
| -rw-r--r-- | contrib/zstd/zstd_decompress.c | 2352 |
1 files changed, 2352 insertions, 0 deletions
diff --git a/contrib/zstd/zstd_decompress.c b/contrib/zstd/zstd_decompress.c new file mode 100644 index 0000000..05704ce --- /dev/null +++ b/contrib/zstd/zstd_decompress.c @@ -0,0 +1,2352 @@ +/* + * Copyright (c) Meta Platforms, Inc. and affiliates. + * All rights reserved. + * + * This source code is licensed under both the BSD-style license (found in the + * LICENSE file in the root directory of this source tree) and the GPLv2 (found + * in the COPYING file in the root directory of this source tree). + * You may select, at your option, one of the above-listed licenses. + */ + + +/* *************************************************************** +* Tuning parameters +*****************************************************************/ +/*! + * HEAPMODE : + * Select how default decompression function ZSTD_decompress() allocates its context, + * on stack (0), or into heap (1, default; requires malloc()). + * Note that functions with explicit context such as ZSTD_decompressDCtx() are unaffected. + */ +#ifndef ZSTD_HEAPMODE +# define ZSTD_HEAPMODE 1 +#endif + +/*! +* LEGACY_SUPPORT : +* if set to 1+, ZSTD_decompress() can decode older formats (v0.1+) +*/ +#ifndef ZSTD_LEGACY_SUPPORT +# define ZSTD_LEGACY_SUPPORT 0 +#endif + +/*! + * MAXWINDOWSIZE_DEFAULT : + * maximum window size accepted by DStream __by default__. + * Frames requiring more memory will be rejected. + * It's possible to set a different limit using ZSTD_DCtx_setMaxWindowSize(). + */ +#ifndef ZSTD_MAXWINDOWSIZE_DEFAULT +# define ZSTD_MAXWINDOWSIZE_DEFAULT (((U32)1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT) + 1) +#endif + +/*! + * NO_FORWARD_PROGRESS_MAX : + * maximum allowed nb of calls to ZSTD_decompressStream() + * without any forward progress + * (defined as: no byte read from input, and no byte flushed to output) + * before triggering an error. + */ +#ifndef ZSTD_NO_FORWARD_PROGRESS_MAX +# define ZSTD_NO_FORWARD_PROGRESS_MAX 16 +#endif + + +/*-******************************************************* +* Dependencies +*********************************************************/ +#include "zstd_deps.h" /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */ +#include "mem.h" /* low level memory routines */ +#define FSE_STATIC_LINKING_ONLY +#include "fse.h" +#include "huf.h" +#include "xxhash.h" /* XXH64_reset, XXH64_update, XXH64_digest, XXH64 */ +#include "zstd_internal.h" /* blockProperties_t */ +#include "zstd_decompress_internal.h" /* ZSTD_DCtx */ +#include "zstd_ddict.h" /* ZSTD_DDictDictContent */ +#include "zstd_decompress_block.h" /* ZSTD_decompressBlock_internal */ +#include "bits.h" /* ZSTD_highbit32 */ + +#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1) +# include "../legacy/zstd_legacy.h" +#endif + + + +/************************************* + * Multiple DDicts Hashset internals * + *************************************/ + +#define DDICT_HASHSET_MAX_LOAD_FACTOR_COUNT_MULT 4 +#define DDICT_HASHSET_MAX_LOAD_FACTOR_SIZE_MULT 3 /* These two constants represent SIZE_MULT/COUNT_MULT load factor without using a float. + * Currently, that means a 0.75 load factor. + * So, if count * COUNT_MULT / size * SIZE_MULT != 0, then we've exceeded + * the load factor of the ddict hash set. + */ + +#define DDICT_HASHSET_TABLE_BASE_SIZE 64 +#define DDICT_HASHSET_RESIZE_FACTOR 2 + +/* Hash function to determine starting position of dict insertion within the table + * Returns an index between [0, hashSet->ddictPtrTableSize] + */ +static size_t ZSTD_DDictHashSet_getIndex(const ZSTD_DDictHashSet* hashSet, U32 dictID) { + const U64 hash = XXH64(&dictID, sizeof(U32), 0); + /* DDict ptr table size is a multiple of 2, use size - 1 as mask to get index within [0, hashSet->ddictPtrTableSize) */ + return hash & (hashSet->ddictPtrTableSize - 1); +} + +/* Adds DDict to a hashset without resizing it. + * If inserting a DDict with a dictID that already exists in the set, replaces the one in the set. + * Returns 0 if successful, or a zstd error code if something went wrong. + */ +static size_t ZSTD_DDictHashSet_emplaceDDict(ZSTD_DDictHashSet* hashSet, const ZSTD_DDict* ddict) { + const U32 dictID = ZSTD_getDictID_fromDDict(ddict); + size_t idx = ZSTD_DDictHashSet_getIndex(hashSet, dictID); + const size_t idxRangeMask = hashSet->ddictPtrTableSize - 1; + RETURN_ERROR_IF(hashSet->ddictPtrCount == hashSet->ddictPtrTableSize, GENERIC, "Hash set is full!"); + DEBUGLOG(4, "Hashed index: for dictID: %u is %zu", dictID, idx); + while (hashSet->ddictPtrTable[idx] != NULL) { + /* Replace existing ddict if inserting ddict with same dictID */ + if (ZSTD_getDictID_fromDDict(hashSet->ddictPtrTable[idx]) == dictID) { + DEBUGLOG(4, "DictID already exists, replacing rather than adding"); + hashSet->ddictPtrTable[idx] = ddict; + return 0; + } + idx &= idxRangeMask; + idx++; + } + DEBUGLOG(4, "Final idx after probing for dictID %u is: %zu", dictID, idx); + hashSet->ddictPtrTable[idx] = ddict; + hashSet->ddictPtrCount++; + return 0; +} + +/* Expands hash table by factor of DDICT_HASHSET_RESIZE_FACTOR and + * rehashes all values, allocates new table, frees old table. + * Returns 0 on success, otherwise a zstd error code. + */ +static size_t ZSTD_DDictHashSet_expand(ZSTD_DDictHashSet* hashSet, ZSTD_customMem customMem) { + size_t newTableSize = hashSet->ddictPtrTableSize * DDICT_HASHSET_RESIZE_FACTOR; + const ZSTD_DDict** newTable = (const ZSTD_DDict**)ZSTD_customCalloc(sizeof(ZSTD_DDict*) * newTableSize, customMem); + const ZSTD_DDict** oldTable = hashSet->ddictPtrTable; + size_t oldTableSize = hashSet->ddictPtrTableSize; + size_t i; + + DEBUGLOG(4, "Expanding DDict hash table! Old size: %zu new size: %zu", oldTableSize, newTableSize); + RETURN_ERROR_IF(!newTable, memory_allocation, "Expanded hashset allocation failed!"); + hashSet->ddictPtrTable = newTable; + hashSet->ddictPtrTableSize = newTableSize; + hashSet->ddictPtrCount = 0; + for (i = 0; i < oldTableSize; ++i) { + if (oldTable[i] != NULL) { + FORWARD_IF_ERROR(ZSTD_DDictHashSet_emplaceDDict(hashSet, oldTable[i]), ""); + } + } + ZSTD_customFree((void*)oldTable, customMem); + DEBUGLOG(4, "Finished re-hash"); + return 0; +} + +/* Fetches a DDict with the given dictID + * Returns the ZSTD_DDict* with the requested dictID. If it doesn't exist, then returns NULL. + */ +static const ZSTD_DDict* ZSTD_DDictHashSet_getDDict(ZSTD_DDictHashSet* hashSet, U32 dictID) { + size_t idx = ZSTD_DDictHashSet_getIndex(hashSet, dictID); + const size_t idxRangeMask = hashSet->ddictPtrTableSize - 1; + DEBUGLOG(4, "Hashed index: for dictID: %u is %zu", dictID, idx); + for (;;) { + size_t currDictID = ZSTD_getDictID_fromDDict(hashSet->ddictPtrTable[idx]); + if (currDictID == dictID || currDictID == 0) { + /* currDictID == 0 implies a NULL ddict entry */ + break; + } else { + idx &= idxRangeMask; /* Goes to start of table when we reach the end */ + idx++; + } + } + DEBUGLOG(4, "Final idx after probing for dictID %u is: %zu", dictID, idx); + return hashSet->ddictPtrTable[idx]; +} + +/* Allocates space for and returns a ddict hash set + * The hash set's ZSTD_DDict* table has all values automatically set to NULL to begin with. + * Returns NULL if allocation failed. + */ +static ZSTD_DDictHashSet* ZSTD_createDDictHashSet(ZSTD_customMem customMem) { + ZSTD_DDictHashSet* ret = (ZSTD_DDictHashSet*)ZSTD_customMalloc(sizeof(ZSTD_DDictHashSet), customMem); + DEBUGLOG(4, "Allocating new hash set"); + if (!ret) + return NULL; + ret->ddictPtrTable = (const ZSTD_DDict**)ZSTD_customCalloc(DDICT_HASHSET_TABLE_BASE_SIZE * sizeof(ZSTD_DDict*), customMem); + if (!ret->ddictPtrTable) { + ZSTD_customFree(ret, customMem); + return NULL; + } + ret->ddictPtrTableSize = DDICT_HASHSET_TABLE_BASE_SIZE; + ret->ddictPtrCount = 0; + return ret; +} + +/* Frees the table of ZSTD_DDict* within a hashset, then frees the hashset itself. + * Note: The ZSTD_DDict* within the table are NOT freed. + */ +static void ZSTD_freeDDictHashSet(ZSTD_DDictHashSet* hashSet, ZSTD_customMem customMem) { + DEBUGLOG(4, "Freeing ddict hash set"); + if (hashSet && hashSet->ddictPtrTable) { + ZSTD_customFree((void*)hashSet->ddictPtrTable, customMem); + } + if (hashSet) { + ZSTD_customFree(hashSet, customMem); + } +} + +/* Public function: Adds a DDict into the ZSTD_DDictHashSet, possibly triggering a resize of the hash set. + * Returns 0 on success, or a ZSTD error. + */ +static size_t ZSTD_DDictHashSet_addDDict(ZSTD_DDictHashSet* hashSet, const ZSTD_DDict* ddict, ZSTD_customMem customMem) { + DEBUGLOG(4, "Adding dict ID: %u to hashset with - Count: %zu Tablesize: %zu", ZSTD_getDictID_fromDDict(ddict), hashSet->ddictPtrCount, hashSet->ddictPtrTableSize); + if (hashSet->ddictPtrCount * DDICT_HASHSET_MAX_LOAD_FACTOR_COUNT_MULT / hashSet->ddictPtrTableSize * DDICT_HASHSET_MAX_LOAD_FACTOR_SIZE_MULT != 0) { + FORWARD_IF_ERROR(ZSTD_DDictHashSet_expand(hashSet, customMem), ""); + } + FORWARD_IF_ERROR(ZSTD_DDictHashSet_emplaceDDict(hashSet, ddict), ""); + return 0; +} + +/*-************************************************************* +* Context management +***************************************************************/ +size_t ZSTD_sizeof_DCtx (const ZSTD_DCtx* dctx) +{ + if (dctx==NULL) return 0; /* support sizeof NULL */ + return sizeof(*dctx) + + ZSTD_sizeof_DDict(dctx->ddictLocal) + + dctx->inBuffSize + dctx->outBuffSize; +} + +size_t ZSTD_estimateDCtxSize(void) { return sizeof(ZSTD_DCtx); } + + +static size_t ZSTD_startingInputLength(ZSTD_format_e format) +{ + size_t const startingInputLength = ZSTD_FRAMEHEADERSIZE_PREFIX(format); + /* only supports formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless */ + assert( (format == ZSTD_f_zstd1) || (format == ZSTD_f_zstd1_magicless) ); + return startingInputLength; +} + +static void ZSTD_DCtx_resetParameters(ZSTD_DCtx* dctx) +{ + assert(dctx->streamStage == zdss_init); + dctx->format = ZSTD_f_zstd1; + dctx->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT; + dctx->outBufferMode = ZSTD_bm_buffered; + dctx->forceIgnoreChecksum = ZSTD_d_validateChecksum; + dctx->refMultipleDDicts = ZSTD_rmd_refSingleDDict; + dctx->disableHufAsm = 0; +} + +static void ZSTD_initDCtx_internal(ZSTD_DCtx* dctx) +{ + dctx->staticSize = 0; + dctx->ddict = NULL; + dctx->ddictLocal = NULL; + dctx->dictEnd = NULL; + dctx->ddictIsCold = 0; + dctx->dictUses = ZSTD_dont_use; + dctx->inBuff = NULL; + dctx->inBuffSize = 0; + dctx->outBuffSize = 0; + dctx->streamStage = zdss_init; +#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1) + dctx->legacyContext = NULL; + dctx->previousLegacyVersion = 0; +#endif + dctx->noForwardProgress = 0; + dctx->oversizedDuration = 0; +#if DYNAMIC_BMI2 + dctx->bmi2 = ZSTD_cpuSupportsBmi2(); +#endif + dctx->ddictSet = NULL; + ZSTD_DCtx_resetParameters(dctx); +#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION + dctx->dictContentEndForFuzzing = NULL; +#endif +} + +ZSTD_DCtx* ZSTD_initStaticDCtx(void *workspace, size_t workspaceSize) +{ + ZSTD_DCtx* const dctx = (ZSTD_DCtx*) workspace; + + if ((size_t)workspace & 7) return NULL; /* 8-aligned */ + if (workspaceSize < sizeof(ZSTD_DCtx)) return NULL; /* minimum size */ + + ZSTD_initDCtx_internal(dctx); + dctx->staticSize = workspaceSize; + dctx->inBuff = (char*)(dctx+1); + return dctx; +} + +static ZSTD_DCtx* ZSTD_createDCtx_internal(ZSTD_customMem customMem) { + if ((!customMem.customAlloc) ^ (!customMem.customFree)) return NULL; + + { ZSTD_DCtx* const dctx = (ZSTD_DCtx*)ZSTD_customMalloc(sizeof(*dctx), customMem); + if (!dctx) return NULL; + dctx->customMem = customMem; + ZSTD_initDCtx_internal(dctx); + return dctx; + } +} + +ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem) +{ + return ZSTD_createDCtx_internal(customMem); +} + +ZSTD_DCtx* ZSTD_createDCtx(void) +{ + DEBUGLOG(3, "ZSTD_createDCtx"); + return ZSTD_createDCtx_internal(ZSTD_defaultCMem); +} + +static void ZSTD_clearDict(ZSTD_DCtx* dctx) +{ + ZSTD_freeDDict(dctx->ddictLocal); + dctx->ddictLocal = NULL; + dctx->ddict = NULL; + dctx->dictUses = ZSTD_dont_use; +} + +size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx) +{ + if (dctx==NULL) return 0; /* support free on NULL */ + RETURN_ERROR_IF(dctx->staticSize, memory_allocation, "not compatible with static DCtx"); + { ZSTD_customMem const cMem = dctx->customMem; + ZSTD_clearDict(dctx); + ZSTD_customFree(dctx->inBuff, cMem); + dctx->inBuff = NULL; +#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1) + if (dctx->legacyContext) + ZSTD_freeLegacyStreamContext(dctx->legacyContext, dctx->previousLegacyVersion); +#endif + if (dctx->ddictSet) { + ZSTD_freeDDictHashSet(dctx->ddictSet, cMem); + dctx->ddictSet = NULL; + } + ZSTD_customFree(dctx, cMem); + return 0; + } +} + +/* no longer useful */ +void ZSTD_copyDCtx(ZSTD_DCtx* dstDCtx, const ZSTD_DCtx* srcDCtx) +{ + size_t const toCopy = (size_t)((char*)(&dstDCtx->inBuff) - (char*)dstDCtx); + ZSTD_memcpy(dstDCtx, srcDCtx, toCopy); /* no need to copy workspace */ +} + +/* Given a dctx with a digested frame params, re-selects the correct ZSTD_DDict based on + * the requested dict ID from the frame. If there exists a reference to the correct ZSTD_DDict, then + * accordingly sets the ddict to be used to decompress the frame. + * + * If no DDict is found, then no action is taken, and the ZSTD_DCtx::ddict remains as-is. + * + * ZSTD_d_refMultipleDDicts must be enabled for this function to be called. + */ +static void ZSTD_DCtx_selectFrameDDict(ZSTD_DCtx* dctx) { + assert(dctx->refMultipleDDicts && dctx->ddictSet); + DEBUGLOG(4, "Adjusting DDict based on requested dict ID from frame"); + if (dctx->ddict) { + const ZSTD_DDict* frameDDict = ZSTD_DDictHashSet_getDDict(dctx->ddictSet, dctx->fParams.dictID); + if (frameDDict) { + DEBUGLOG(4, "DDict found!"); + ZSTD_clearDict(dctx); + dctx->dictID = dctx->fParams.dictID; + dctx->ddict = frameDDict; + dctx->dictUses = ZSTD_use_indefinitely; + } + } +} + + +/*-************************************************************* + * Frame header decoding + ***************************************************************/ + +/*! ZSTD_isFrame() : + * Tells if the content of `buffer` starts with a valid Frame Identifier. + * Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0. + * Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled. + * Note 3 : Skippable Frame Identifiers are considered valid. */ +unsigned ZSTD_isFrame(const void* buffer, size_t size) +{ + if (size < ZSTD_FRAMEIDSIZE) return 0; + { U32 const magic = MEM_readLE32(buffer); + if (magic == ZSTD_MAGICNUMBER) return 1; + if ((magic & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) return 1; + } +#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1) + if (ZSTD_isLegacy(buffer, size)) return 1; +#endif + return 0; +} + +/*! ZSTD_isSkippableFrame() : + * Tells if the content of `buffer` starts with a valid Frame Identifier for a skippable frame. + * Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0. + */ +unsigned ZSTD_isSkippableFrame(const void* buffer, size_t size) +{ + if (size < ZSTD_FRAMEIDSIZE) return 0; + { U32 const magic = MEM_readLE32(buffer); + if ((magic & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) return 1; + } + return 0; +} + +/** ZSTD_frameHeaderSize_internal() : + * srcSize must be large enough to reach header size fields. + * note : only works for formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless. + * @return : size of the Frame Header + * or an error code, which can be tested with ZSTD_isError() */ +static size_t ZSTD_frameHeaderSize_internal(const void* src, size_t srcSize, ZSTD_format_e format) +{ + size_t const minInputSize = ZSTD_startingInputLength(format); + RETURN_ERROR_IF(srcSize < minInputSize, srcSize_wrong, ""); + + { BYTE const fhd = ((const BYTE*)src)[minInputSize-1]; + U32 const dictID= fhd & 3; + U32 const singleSegment = (fhd >> 5) & 1; + U32 const fcsId = fhd >> 6; + return minInputSize + !singleSegment + + ZSTD_did_fieldSize[dictID] + ZSTD_fcs_fieldSize[fcsId] + + (singleSegment && !fcsId); + } +} + +/** ZSTD_frameHeaderSize() : + * srcSize must be >= ZSTD_frameHeaderSize_prefix. + * @return : size of the Frame Header, + * or an error code (if srcSize is too small) */ +size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize) +{ + return ZSTD_frameHeaderSize_internal(src, srcSize, ZSTD_f_zstd1); +} + + +/** ZSTD_getFrameHeader_advanced() : + * decode Frame Header, or require larger `srcSize`. + * note : only works for formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless + * @return : 0, `zfhPtr` is correctly filled, + * >0, `srcSize` is too small, value is wanted `srcSize` amount, +** or an error code, which can be tested using ZSTD_isError() */ +size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize, ZSTD_format_e format) +{ + const BYTE* ip = (const BYTE*)src; + size_t const minInputSize = ZSTD_startingInputLength(format); + + DEBUGLOG(5, "ZSTD_getFrameHeader_advanced: minInputSize = %zu, srcSize = %zu", minInputSize, srcSize); + + if (srcSize > 0) { + /* note : technically could be considered an assert(), since it's an invalid entry */ + RETURN_ERROR_IF(src==NULL, GENERIC, "invalid parameter : src==NULL, but srcSize>0"); + } + if (srcSize < minInputSize) { + if (srcSize > 0 && format != ZSTD_f_zstd1_magicless) { + /* when receiving less than @minInputSize bytes, + * control these bytes at least correspond to a supported magic number + * in order to error out early if they don't. + **/ + size_t const toCopy = MIN(4, srcSize); + unsigned char hbuf[4]; MEM_writeLE32(hbuf, ZSTD_MAGICNUMBER); + assert(src != NULL); + ZSTD_memcpy(hbuf, src, toCopy); + if ( MEM_readLE32(hbuf) != ZSTD_MAGICNUMBER ) { + /* not a zstd frame : let's check if it's a skippable frame */ + MEM_writeLE32(hbuf, ZSTD_MAGIC_SKIPPABLE_START); + ZSTD_memcpy(hbuf, src, toCopy); + if ((MEM_readLE32(hbuf) & ZSTD_MAGIC_SKIPPABLE_MASK) != ZSTD_MAGIC_SKIPPABLE_START) { + RETURN_ERROR(prefix_unknown, + "first bytes don't correspond to any supported magic number"); + } } } + return minInputSize; + } + + ZSTD_memset(zfhPtr, 0, sizeof(*zfhPtr)); /* not strictly necessary, but static analyzers may not understand that zfhPtr will be read only if return value is zero, since they are 2 different signals */ + if ( (format != ZSTD_f_zstd1_magicless) + && (MEM_readLE32(src) != ZSTD_MAGICNUMBER) ) { + if ((MEM_readLE32(src) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { + /* skippable frame */ + if (srcSize < ZSTD_SKIPPABLEHEADERSIZE) + return ZSTD_SKIPPABLEHEADERSIZE; /* magic number + frame length */ + ZSTD_memset(zfhPtr, 0, sizeof(*zfhPtr)); + zfhPtr->frameContentSize = MEM_readLE32((const char *)src + ZSTD_FRAMEIDSIZE); + zfhPtr->frameType = ZSTD_skippableFrame; + return 0; + } + RETURN_ERROR(prefix_unknown, ""); + } + + /* ensure there is enough `srcSize` to fully read/decode frame header */ + { size_t const fhsize = ZSTD_frameHeaderSize_internal(src, srcSize, format); + if (srcSize < fhsize) return fhsize; + zfhPtr->headerSize = (U32)fhsize; + } + + { BYTE const fhdByte = ip[minInputSize-1]; + size_t pos = minInputSize; + U32 const dictIDSizeCode = fhdByte&3; + U32 const checksumFlag = (fhdByte>>2)&1; + U32 const singleSegment = (fhdByte>>5)&1; + U32 const fcsID = fhdByte>>6; + U64 windowSize = 0; + U32 dictID = 0; + U64 frameContentSize = ZSTD_CONTENTSIZE_UNKNOWN; + RETURN_ERROR_IF((fhdByte & 0x08) != 0, frameParameter_unsupported, + "reserved bits, must be zero"); + + if (!singleSegment) { + BYTE const wlByte = ip[pos++]; + U32 const windowLog = (wlByte >> 3) + ZSTD_WINDOWLOG_ABSOLUTEMIN; + RETURN_ERROR_IF(windowLog > ZSTD_WINDOWLOG_MAX, frameParameter_windowTooLarge, ""); + windowSize = (1ULL << windowLog); + windowSize += (windowSize >> 3) * (wlByte&7); + } + switch(dictIDSizeCode) + { + default: + assert(0); /* impossible */ + ZSTD_FALLTHROUGH; + case 0 : break; + case 1 : dictID = ip[pos]; pos++; break; + case 2 : dictID = MEM_readLE16(ip+pos); pos+=2; break; + case 3 : dictID = MEM_readLE32(ip+pos); pos+=4; break; + } + switch(fcsID) + { + default: + assert(0); /* impossible */ + ZSTD_FALLTHROUGH; + case 0 : if (singleSegment) frameContentSize = ip[pos]; break; + case 1 : frameContentSize = MEM_readLE16(ip+pos)+256; break; + case 2 : frameContentSize = MEM_readLE32(ip+pos); break; + case 3 : frameContentSize = MEM_readLE64(ip+pos); break; + } + if (singleSegment) windowSize = frameContentSize; + + zfhPtr->frameType = ZSTD_frame; + zfhPtr->frameContentSize = frameContentSize; + zfhPtr->windowSize = windowSize; + zfhPtr->blockSizeMax = (unsigned) MIN(windowSize, ZSTD_BLOCKSIZE_MAX); + zfhPtr->dictID = dictID; + zfhPtr->checksumFlag = checksumFlag; + } + return 0; +} + +/** ZSTD_getFrameHeader() : + * decode Frame Header, or require larger `srcSize`. + * note : this function does not consume input, it only reads it. + * @return : 0, `zfhPtr` is correctly filled, + * >0, `srcSize` is too small, value is wanted `srcSize` amount, + * or an error code, which can be tested using ZSTD_isError() */ +size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize) +{ + return ZSTD_getFrameHeader_advanced(zfhPtr, src, srcSize, ZSTD_f_zstd1); +} + +/** ZSTD_getFrameContentSize() : + * compatible with legacy mode + * @return : decompressed size of the single frame pointed to be `src` if known, otherwise + * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined + * - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) */ +unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize) +{ +#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1) + if (ZSTD_isLegacy(src, srcSize)) { + unsigned long long const ret = ZSTD_getDecompressedSize_legacy(src, srcSize); + return ret == 0 ? ZSTD_CONTENTSIZE_UNKNOWN : ret; + } +#endif + { ZSTD_frameHeader zfh; + if (ZSTD_getFrameHeader(&zfh, src, srcSize) != 0) + return ZSTD_CONTENTSIZE_ERROR; + if (zfh.frameType == ZSTD_skippableFrame) { + return 0; + } else { + return zfh.frameContentSize; + } } +} + +static size_t readSkippableFrameSize(void const* src, size_t srcSize) +{ + size_t const skippableHeaderSize = ZSTD_SKIPPABLEHEADERSIZE; + U32 sizeU32; + + RETURN_ERROR_IF(srcSize < ZSTD_SKIPPABLEHEADERSIZE, srcSize_wrong, ""); + + sizeU32 = MEM_readLE32((BYTE const*)src + ZSTD_FRAMEIDSIZE); + RETURN_ERROR_IF((U32)(sizeU32 + ZSTD_SKIPPABLEHEADERSIZE) < sizeU32, + frameParameter_unsupported, ""); + { + size_t const skippableSize = skippableHeaderSize + sizeU32; + RETURN_ERROR_IF(skippableSize > srcSize, srcSize_wrong, ""); + return skippableSize; + } +} + +/*! ZSTD_readSkippableFrame() : + * Retrieves a zstd skippable frame containing data given by src, and writes it to dst buffer. + * + * The parameter magicVariant will receive the magicVariant that was supplied when the frame was written, + * i.e. magicNumber - ZSTD_MAGIC_SKIPPABLE_START. This can be NULL if the caller is not interested + * in the magicVariant. + * + * Returns an error if destination buffer is not large enough, or if the frame is not skippable. + * + * @return : number of bytes written or a ZSTD error. + */ +ZSTDLIB_API size_t ZSTD_readSkippableFrame(void* dst, size_t dstCapacity, unsigned* magicVariant, + const void* src, size_t srcSize) +{ + U32 const magicNumber = MEM_readLE32(src); + size_t skippableFrameSize = readSkippableFrameSize(src, srcSize); + size_t skippableContentSize = skippableFrameSize - ZSTD_SKIPPABLEHEADERSIZE; + + /* check input validity */ + RETURN_ERROR_IF(!ZSTD_isSkippableFrame(src, srcSize), frameParameter_unsupported, ""); + RETURN_ERROR_IF(skippableFrameSize < ZSTD_SKIPPABLEHEADERSIZE || skippableFrameSize > srcSize, srcSize_wrong, ""); + RETURN_ERROR_IF(skippableContentSize > dstCapacity, dstSize_tooSmall, ""); + + /* deliver payload */ + if (skippableContentSize > 0 && dst != NULL) + ZSTD_memcpy(dst, (const BYTE *)src + ZSTD_SKIPPABLEHEADERSIZE, skippableContentSize); + if (magicVariant != NULL) + *magicVariant = magicNumber - ZSTD_MAGIC_SKIPPABLE_START; + return skippableContentSize; +} + +/** ZSTD_findDecompressedSize() : + * compatible with legacy mode + * `srcSize` must be the exact length of some number of ZSTD compressed and/or + * skippable frames + * @return : decompressed size of the frames contained */ +unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize) +{ + unsigned long long totalDstSize = 0; + + while (srcSize >= ZSTD_startingInputLength(ZSTD_f_zstd1)) { + U32 const magicNumber = MEM_readLE32(src); + + if ((magicNumber & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { + size_t const skippableSize = readSkippableFrameSize(src, srcSize); + if (ZSTD_isError(skippableSize)) { + return ZSTD_CONTENTSIZE_ERROR; + } + assert(skippableSize <= srcSize); + + src = (const BYTE *)src + skippableSize; + srcSize -= skippableSize; + continue; + } + + { unsigned long long const ret = ZSTD_getFrameContentSize(src, srcSize); + if (ret >= ZSTD_CONTENTSIZE_ERROR) return ret; + + /* check for overflow */ + if (totalDstSize + ret < totalDstSize) return ZSTD_CONTENTSIZE_ERROR; + totalDstSize += ret; + } + { size_t const frameSrcSize = ZSTD_findFrameCompressedSize(src, srcSize); + if (ZSTD_isError(frameSrcSize)) { + return ZSTD_CONTENTSIZE_ERROR; + } + + src = (const BYTE *)src + frameSrcSize; + srcSize -= frameSrcSize; + } + } /* while (srcSize >= ZSTD_frameHeaderSize_prefix) */ + + if (srcSize) return ZSTD_CONTENTSIZE_ERROR; + + return totalDstSize; +} + +/** ZSTD_getDecompressedSize() : + * compatible with legacy mode + * @return : decompressed size if known, 0 otherwise + note : 0 can mean any of the following : + - frame content is empty + - decompressed size field is not present in frame header + - frame header unknown / not supported + - frame header not complete (`srcSize` too small) */ +unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize) +{ + unsigned long long const ret = ZSTD_getFrameContentSize(src, srcSize); + ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_ERROR < ZSTD_CONTENTSIZE_UNKNOWN); + return (ret >= ZSTD_CONTENTSIZE_ERROR) ? 0 : ret; +} + + +/** ZSTD_decodeFrameHeader() : + * `headerSize` must be the size provided by ZSTD_frameHeaderSize(). + * If multiple DDict references are enabled, also will choose the correct DDict to use. + * @return : 0 if success, or an error code, which can be tested using ZSTD_isError() */ +static size_t ZSTD_decodeFrameHeader(ZSTD_DCtx* dctx, const void* src, size_t headerSize) +{ + size_t const result = ZSTD_getFrameHeader_advanced(&(dctx->fParams), src, headerSize, dctx->format); + if (ZSTD_isError(result)) return result; /* invalid header */ + RETURN_ERROR_IF(result>0, srcSize_wrong, "headerSize too small"); + + /* Reference DDict requested by frame if dctx references multiple ddicts */ + if (dctx->refMultipleDDicts == ZSTD_rmd_refMultipleDDicts && dctx->ddictSet) { + ZSTD_DCtx_selectFrameDDict(dctx); + } + +#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION + /* Skip the dictID check in fuzzing mode, because it makes the search + * harder. + */ + RETURN_ERROR_IF(dctx->fParams.dictID && (dctx->dictID != dctx->fParams.dictID), + dictionary_wrong, ""); +#endif + dctx->validateChecksum = (dctx->fParams.checksumFlag && !dctx->forceIgnoreChecksum) ? 1 : 0; + if (dctx->validateChecksum) XXH64_reset(&dctx->xxhState, 0); + dctx->processedCSize += headerSize; + return 0; +} + +static ZSTD_frameSizeInfo ZSTD_errorFrameSizeInfo(size_t ret) +{ + ZSTD_frameSizeInfo frameSizeInfo; + frameSizeInfo.compressedSize = ret; + frameSizeInfo.decompressedBound = ZSTD_CONTENTSIZE_ERROR; + return frameSizeInfo; +} + +static ZSTD_frameSizeInfo ZSTD_findFrameSizeInfo(const void* src, size_t srcSize) +{ + ZSTD_frameSizeInfo frameSizeInfo; + ZSTD_memset(&frameSizeInfo, 0, sizeof(ZSTD_frameSizeInfo)); + +#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1) + if (ZSTD_isLegacy(src, srcSize)) + return ZSTD_findFrameSizeInfoLegacy(src, srcSize); +#endif + + if ((srcSize >= ZSTD_SKIPPABLEHEADERSIZE) + && (MEM_readLE32(src) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { + frameSizeInfo.compressedSize = readSkippableFrameSize(src, srcSize); + assert(ZSTD_isError(frameSizeInfo.compressedSize) || + frameSizeInfo.compressedSize <= srcSize); + return frameSizeInfo; + } else { + const BYTE* ip = (const BYTE*)src; + const BYTE* const ipstart = ip; + size_t remainingSize = srcSize; + size_t nbBlocks = 0; + ZSTD_frameHeader zfh; + + /* Extract Frame Header */ + { size_t const ret = ZSTD_getFrameHeader(&zfh, src, srcSize); + if (ZSTD_isError(ret)) + return ZSTD_errorFrameSizeInfo(ret); + if (ret > 0) + return ZSTD_errorFrameSizeInfo(ERROR(srcSize_wrong)); + } + + ip += zfh.headerSize; + remainingSize -= zfh.headerSize; + + /* Iterate over each block */ + while (1) { + blockProperties_t blockProperties; + size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties); + if (ZSTD_isError(cBlockSize)) + return ZSTD_errorFrameSizeInfo(cBlockSize); + + if (ZSTD_blockHeaderSize + cBlockSize > remainingSize) + return ZSTD_errorFrameSizeInfo(ERROR(srcSize_wrong)); + + ip += ZSTD_blockHeaderSize + cBlockSize; + remainingSize -= ZSTD_blockHeaderSize + cBlockSize; + nbBlocks++; + + if (blockProperties.lastBlock) break; + } + + /* Final frame content checksum */ + if (zfh.checksumFlag) { + if (remainingSize < 4) + return ZSTD_errorFrameSizeInfo(ERROR(srcSize_wrong)); + ip += 4; + } + + frameSizeInfo.nbBlocks = nbBlocks; + frameSizeInfo.compressedSize = (size_t)(ip - ipstart); + frameSizeInfo.decompressedBound = (zfh.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN) + ? zfh.frameContentSize + : (unsigned long long)nbBlocks * zfh.blockSizeMax; + return frameSizeInfo; + } +} + +/** ZSTD_findFrameCompressedSize() : + * compatible with legacy mode + * `src` must point to the start of a ZSTD frame, ZSTD legacy frame, or skippable frame + * `srcSize` must be at least as large as the frame contained + * @return : the compressed size of the frame starting at `src` */ +size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize) +{ + ZSTD_frameSizeInfo const frameSizeInfo = ZSTD_findFrameSizeInfo(src, srcSize); + return frameSizeInfo.compressedSize; +} + +/** ZSTD_decompressBound() : + * compatible with legacy mode + * `src` must point to the start of a ZSTD frame or a skippeable frame + * `srcSize` must be at least as large as the frame contained + * @return : the maximum decompressed size of the compressed source + */ +unsigned long long ZSTD_decompressBound(const void* src, size_t srcSize) +{ + unsigned long long bound = 0; + /* Iterate over each frame */ + while (srcSize > 0) { + ZSTD_frameSizeInfo const frameSizeInfo = ZSTD_findFrameSizeInfo(src, srcSize); + size_t const compressedSize = frameSizeInfo.compressedSize; + unsigned long long const decompressedBound = frameSizeInfo.decompressedBound; + if (ZSTD_isError(compressedSize) || decompressedBound == ZSTD_CONTENTSIZE_ERROR) + return ZSTD_CONTENTSIZE_ERROR; + assert(srcSize >= compressedSize); + src = (const BYTE*)src + compressedSize; + srcSize -= compressedSize; + bound += decompressedBound; + } + return bound; +} + +size_t ZSTD_decompressionMargin(void const* src, size_t srcSize) +{ + size_t margin = 0; + unsigned maxBlockSize = 0; + + /* Iterate over each frame */ + while (srcSize > 0) { + ZSTD_frameSizeInfo const frameSizeInfo = ZSTD_findFrameSizeInfo(src, srcSize); + size_t const compressedSize = frameSizeInfo.compressedSize; + unsigned long long const decompressedBound = frameSizeInfo.decompressedBound; + ZSTD_frameHeader zfh; + + FORWARD_IF_ERROR(ZSTD_getFrameHeader(&zfh, src, srcSize), ""); + if (ZSTD_isError(compressedSize) || decompressedBound == ZSTD_CONTENTSIZE_ERROR) + return ERROR(corruption_detected); + + if (zfh.frameType == ZSTD_frame) { + /* Add the frame header to our margin */ + margin += zfh.headerSize; + /* Add the checksum to our margin */ + margin += zfh.checksumFlag ? 4 : 0; + /* Add 3 bytes per block */ + margin += 3 * frameSizeInfo.nbBlocks; + + /* Compute the max block size */ + maxBlockSize = MAX(maxBlockSize, zfh.blockSizeMax); + } else { + assert(zfh.frameType == ZSTD_skippableFrame); + /* Add the entire skippable frame size to our margin. */ + margin += compressedSize; + } + + assert(srcSize >= compressedSize); + src = (const BYTE*)src + compressedSize; + srcSize -= compressedSize; + } + + /* Add the max block size back to the margin. */ + margin += maxBlockSize; + + return margin; +} + +/*-************************************************************* + * Frame decoding + ***************************************************************/ + +/** ZSTD_insertBlock() : + * insert `src` block into `dctx` history. Useful to track uncompressed blocks. */ +size_t ZSTD_insertBlock(ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize) +{ + DEBUGLOG(5, "ZSTD_insertBlock: %u bytes", (unsigned)blockSize); + ZSTD_checkContinuity(dctx, blockStart, blockSize); + dctx->previousDstEnd = (const char*)blockStart + blockSize; + return blockSize; +} + + +static size_t ZSTD_copyRawBlock(void* dst, size_t dstCapacity, + const void* src, size_t srcSize) +{ + DEBUGLOG(5, "ZSTD_copyRawBlock"); + RETURN_ERROR_IF(srcSize > dstCapacity, dstSize_tooSmall, ""); + if (dst == NULL) { + if (srcSize == 0) return 0; + RETURN_ERROR(dstBuffer_null, ""); + } + ZSTD_memmove(dst, src, srcSize); + return srcSize; +} + +static size_t ZSTD_setRleBlock(void* dst, size_t dstCapacity, + BYTE b, + size_t regenSize) +{ + RETURN_ERROR_IF(regenSize > dstCapacity, dstSize_tooSmall, ""); + if (dst == NULL) { + if (regenSize == 0) return 0; + RETURN_ERROR(dstBuffer_null, ""); + } + ZSTD_memset(dst, b, regenSize); + return regenSize; +} + +static void ZSTD_DCtx_trace_end(ZSTD_DCtx const* dctx, U64 uncompressedSize, U64 compressedSize, unsigned streaming) +{ +#if ZSTD_TRACE + if (dctx->traceCtx && ZSTD_trace_decompress_end != NULL) { + ZSTD_Trace trace; + ZSTD_memset(&trace, 0, sizeof(trace)); + trace.version = ZSTD_VERSION_NUMBER; + trace.streaming = streaming; + if (dctx->ddict) { + trace.dictionaryID = ZSTD_getDictID_fromDDict(dctx->ddict); + trace.dictionarySize = ZSTD_DDict_dictSize(dctx->ddict); + trace.dictionaryIsCold = dctx->ddictIsCold; + } + trace.uncompressedSize = (size_t)uncompressedSize; + trace.compressedSize = (size_t)compressedSize; + trace.dctx = dctx; + ZSTD_trace_decompress_end(dctx->traceCtx, &trace); + } +#else + (void)dctx; + (void)uncompressedSize; + (void)compressedSize; + (void)streaming; +#endif +} + + +/*! ZSTD_decompressFrame() : + * @dctx must be properly initialized + * will update *srcPtr and *srcSizePtr, + * to make *srcPtr progress by one frame. */ +static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx, + void* dst, size_t dstCapacity, + const void** srcPtr, size_t *srcSizePtr) +{ + const BYTE* const istart = (const BYTE*)(*srcPtr); + const BYTE* ip = istart; + BYTE* const ostart = (BYTE*)dst; + BYTE* const oend = dstCapacity != 0 ? ostart + dstCapacity : ostart; + BYTE* op = ostart; + size_t remainingSrcSize = *srcSizePtr; + + DEBUGLOG(4, "ZSTD_decompressFrame (srcSize:%i)", (int)*srcSizePtr); + + /* check */ + RETURN_ERROR_IF( + remainingSrcSize < ZSTD_FRAMEHEADERSIZE_MIN(dctx->format)+ZSTD_blockHeaderSize, + srcSize_wrong, ""); + + /* Frame Header */ + { size_t const frameHeaderSize = ZSTD_frameHeaderSize_internal( + ip, ZSTD_FRAMEHEADERSIZE_PREFIX(dctx->format), dctx->format); + if (ZSTD_isError(frameHeaderSize)) return frameHeaderSize; + RETURN_ERROR_IF(remainingSrcSize < frameHeaderSize+ZSTD_blockHeaderSize, + srcSize_wrong, ""); + FORWARD_IF_ERROR( ZSTD_decodeFrameHeader(dctx, ip, frameHeaderSize) , ""); + ip += frameHeaderSize; remainingSrcSize -= frameHeaderSize; + } + + /* Loop on each block */ + while (1) { + BYTE* oBlockEnd = oend; + size_t decodedSize; + blockProperties_t blockProperties; + size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSrcSize, &blockProperties); + if (ZSTD_isError(cBlockSize)) return cBlockSize; + + ip += ZSTD_blockHeaderSize; + remainingSrcSize -= ZSTD_blockHeaderSize; + RETURN_ERROR_IF(cBlockSize > remainingSrcSize, srcSize_wrong, ""); + + if (ip >= op && ip < oBlockEnd) { + /* We are decompressing in-place. Limit the output pointer so that we + * don't overwrite the block that we are currently reading. This will + * fail decompression if the input & output pointers aren't spaced + * far enough apart. + * + * This is important to set, even when the pointers are far enough + * apart, because ZSTD_decompressBlock_internal() can decide to store + * literals in the output buffer, after the block it is decompressing. + * Since we don't want anything to overwrite our input, we have to tell + * ZSTD_decompressBlock_internal to never write past ip. + * + * See ZSTD_allocateLiteralsBuffer() for reference. + */ + oBlockEnd = op + (ip - op); + } + + switch(blockProperties.blockType) + { + case bt_compressed: + decodedSize = ZSTD_decompressBlock_internal(dctx, op, (size_t)(oBlockEnd-op), ip, cBlockSize, /* frame */ 1, not_streaming); + break; + case bt_raw : + /* Use oend instead of oBlockEnd because this function is safe to overlap. It uses memmove. */ + decodedSize = ZSTD_copyRawBlock(op, (size_t)(oend-op), ip, cBlockSize); + break; + case bt_rle : + decodedSize = ZSTD_setRleBlock(op, (size_t)(oBlockEnd-op), *ip, blockProperties.origSize); + break; + case bt_reserved : + default: + RETURN_ERROR(corruption_detected, "invalid block type"); + } + + if (ZSTD_isError(decodedSize)) return decodedSize; + if (dctx->validateChecksum) + XXH64_update(&dctx->xxhState, op, decodedSize); + if (decodedSize != 0) + op += decodedSize; + assert(ip != NULL); + ip += cBlockSize; + remainingSrcSize -= cBlockSize; + if (blockProperties.lastBlock) break; + } + + if (dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN) { + RETURN_ERROR_IF((U64)(op-ostart) != dctx->fParams.frameContentSize, + corruption_detected, ""); + } + if (dctx->fParams.checksumFlag) { /* Frame content checksum verification */ + RETURN_ERROR_IF(remainingSrcSize<4, checksum_wrong, ""); + if (!dctx->forceIgnoreChecksum) { + U32 const checkCalc = (U32)XXH64_digest(&dctx->xxhState); + U32 checkRead; + checkRead = MEM_readLE32(ip); + RETURN_ERROR_IF(checkRead != checkCalc, checksum_wrong, ""); + } + ip += 4; + remainingSrcSize -= 4; + } + ZSTD_DCtx_trace_end(dctx, (U64)(op-ostart), (U64)(ip-istart), /* streaming */ 0); + /* Allow caller to get size read */ + DEBUGLOG(4, "ZSTD_decompressFrame: decompressed frame of size %zi, consuming %zi bytes of input", op-ostart, ip - (const BYTE*)*srcPtr); + *srcPtr = ip; + *srcSizePtr = remainingSrcSize; + return (size_t)(op-ostart); +} + +static size_t ZSTD_decompressMultiFrame(ZSTD_DCtx* dctx, + void* dst, size_t dstCapacity, + const void* src, size_t srcSize, + const void* dict, size_t dictSize, + const ZSTD_DDict* ddict) +{ + void* const dststart = dst; + int moreThan1Frame = 0; + + DEBUGLOG(5, "ZSTD_decompressMultiFrame"); + assert(dict==NULL || ddict==NULL); /* either dict or ddict set, not both */ + + if (ddict) { + dict = ZSTD_DDict_dictContent(ddict); + dictSize = ZSTD_DDict_dictSize(ddict); + } + + while (srcSize >= ZSTD_startingInputLength(dctx->format)) { + +#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1) + if (ZSTD_isLegacy(src, srcSize)) { + size_t decodedSize; + size_t const frameSize = ZSTD_findFrameCompressedSizeLegacy(src, srcSize); + if (ZSTD_isError(frameSize)) return frameSize; + RETURN_ERROR_IF(dctx->staticSize, memory_allocation, + "legacy support is not compatible with static dctx"); + + decodedSize = ZSTD_decompressLegacy(dst, dstCapacity, src, frameSize, dict, dictSize); + if (ZSTD_isError(decodedSize)) return decodedSize; + + assert(decodedSize <= dstCapacity); + dst = (BYTE*)dst + decodedSize; + dstCapacity -= decodedSize; + + src = (const BYTE*)src + frameSize; + srcSize -= frameSize; + + continue; + } +#endif + + { U32 const magicNumber = MEM_readLE32(src); + DEBUGLOG(4, "reading magic number %08X (expecting %08X)", + (unsigned)magicNumber, ZSTD_MAGICNUMBER); + if ((magicNumber & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { + size_t const skippableSize = readSkippableFrameSize(src, srcSize); + FORWARD_IF_ERROR(skippableSize, "readSkippableFrameSize failed"); + assert(skippableSize <= srcSize); + + src = (const BYTE *)src + skippableSize; + srcSize -= skippableSize; + continue; + } } + + if (ddict) { + /* we were called from ZSTD_decompress_usingDDict */ + FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(dctx, ddict), ""); + } else { + /* this will initialize correctly with no dict if dict == NULL, so + * use this in all cases but ddict */ + FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDict(dctx, dict, dictSize), ""); + } + ZSTD_checkContinuity(dctx, dst, dstCapacity); + + { const size_t res = ZSTD_decompressFrame(dctx, dst, dstCapacity, + &src, &srcSize); + RETURN_ERROR_IF( + (ZSTD_getErrorCode(res) == ZSTD_error_prefix_unknown) + && (moreThan1Frame==1), + srcSize_wrong, + "At least one frame successfully completed, " + "but following bytes are garbage: " + "it's more likely to be a srcSize error, " + "specifying more input bytes than size of frame(s). " + "Note: one could be unlucky, it might be a corruption error instead, " + "happening right at the place where we expect zstd magic bytes. " + "But this is _much_ less likely than a srcSize field error."); + if (ZSTD_isError(res)) return res; + assert(res <= dstCapacity); + if (res != 0) + dst = (BYTE*)dst + res; + dstCapacity -= res; + } + moreThan1Frame = 1; + } /* while (srcSize >= ZSTD_frameHeaderSize_prefix) */ + + RETURN_ERROR_IF(srcSize, srcSize_wrong, "input not entirely consumed"); + + return (size_t)((BYTE*)dst - (BYTE*)dststart); +} + +size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx, + void* dst, size_t dstCapacity, + const void* src, size_t srcSize, + const void* dict, size_t dictSize) +{ + return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize, dict, dictSize, NULL); +} + + +static ZSTD_DDict const* ZSTD_getDDict(ZSTD_DCtx* dctx) +{ + switch (dctx->dictUses) { + default: + assert(0 /* Impossible */); + ZSTD_FALLTHROUGH; + case ZSTD_dont_use: + ZSTD_clearDict(dctx); + return NULL; + case ZSTD_use_indefinitely: + return dctx->ddict; + case ZSTD_use_once: + dctx->dictUses = ZSTD_dont_use; + return dctx->ddict; + } +} + +size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize) +{ + return ZSTD_decompress_usingDDict(dctx, dst, dstCapacity, src, srcSize, ZSTD_getDDict(dctx)); +} + + +size_t ZSTD_decompress(void* dst, size_t dstCapacity, const void* src, size_t srcSize) +{ +#if defined(ZSTD_HEAPMODE) && (ZSTD_HEAPMODE>=1) + size_t regenSize; + ZSTD_DCtx* const dctx = ZSTD_createDCtx_internal(ZSTD_defaultCMem); + RETURN_ERROR_IF(dctx==NULL, memory_allocation, "NULL pointer!"); + regenSize = ZSTD_decompressDCtx(dctx, dst, dstCapacity, src, srcSize); + ZSTD_freeDCtx(dctx); + return regenSize; +#else /* stack mode */ + ZSTD_DCtx dctx; + ZSTD_initDCtx_internal(&dctx); + return ZSTD_decompressDCtx(&dctx, dst, dstCapacity, src, srcSize); +#endif +} + + +/*-************************************** +* Advanced Streaming Decompression API +* Bufferless and synchronous +****************************************/ +size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx) { return dctx->expected; } + +/** + * Similar to ZSTD_nextSrcSizeToDecompress(), but when a block input can be streamed, we + * allow taking a partial block as the input. Currently only raw uncompressed blocks can + * be streamed. + * + * For blocks that can be streamed, this allows us to reduce the latency until we produce + * output, and avoid copying the input. + * + * @param inputSize - The total amount of input that the caller currently has. + */ +static size_t ZSTD_nextSrcSizeToDecompressWithInputSize(ZSTD_DCtx* dctx, size_t inputSize) { + if (!(dctx->stage == ZSTDds_decompressBlock || dctx->stage == ZSTDds_decompressLastBlock)) + return dctx->expected; + if (dctx->bType != bt_raw) + return dctx->expected; + return BOUNDED(1, inputSize, dctx->expected); +} + +ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx) { + switch(dctx->stage) + { + default: /* should not happen */ + assert(0); + ZSTD_FALLTHROUGH; + case ZSTDds_getFrameHeaderSize: + ZSTD_FALLTHROUGH; + case ZSTDds_decodeFrameHeader: + return ZSTDnit_frameHeader; + case ZSTDds_decodeBlockHeader: + return ZSTDnit_blockHeader; + case ZSTDds_decompressBlock: + return ZSTDnit_block; + case ZSTDds_decompressLastBlock: + return ZSTDnit_lastBlock; + case ZSTDds_checkChecksum: + return ZSTDnit_checksum; + case ZSTDds_decodeSkippableHeader: + ZSTD_FALLTHROUGH; + case ZSTDds_skipFrame: + return ZSTDnit_skippableFrame; + } +} + +static int ZSTD_isSkipFrame(ZSTD_DCtx* dctx) { return dctx->stage == ZSTDds_skipFrame; } + +/** ZSTD_decompressContinue() : + * srcSize : must be the exact nb of bytes expected (see ZSTD_nextSrcSizeToDecompress()) + * @return : nb of bytes generated into `dst` (necessarily <= `dstCapacity) + * or an error code, which can be tested using ZSTD_isError() */ +size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize) +{ + DEBUGLOG(5, "ZSTD_decompressContinue (srcSize:%u)", (unsigned)srcSize); + /* Sanity check */ + RETURN_ERROR_IF(srcSize != ZSTD_nextSrcSizeToDecompressWithInputSize(dctx, srcSize), srcSize_wrong, "not allowed"); + ZSTD_checkContinuity(dctx, dst, dstCapacity); + + dctx->processedCSize += srcSize; + + switch (dctx->stage) + { + case ZSTDds_getFrameHeaderSize : + assert(src != NULL); + if (dctx->format == ZSTD_f_zstd1) { /* allows header */ + assert(srcSize >= ZSTD_FRAMEIDSIZE); /* to read skippable magic number */ + if ((MEM_readLE32(src) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */ + ZSTD_memcpy(dctx->headerBuffer, src, srcSize); + dctx->expected = ZSTD_SKIPPABLEHEADERSIZE - srcSize; /* remaining to load to get full skippable frame header */ + dctx->stage = ZSTDds_decodeSkippableHeader; + return 0; + } } + dctx->headerSize = ZSTD_frameHeaderSize_internal(src, srcSize, dctx->format); + if (ZSTD_isError(dctx->headerSize)) return dctx->headerSize; + ZSTD_memcpy(dctx->headerBuffer, src, srcSize); + dctx->expected = dctx->headerSize - srcSize; + dctx->stage = ZSTDds_decodeFrameHeader; + return 0; + + case ZSTDds_decodeFrameHeader: + assert(src != NULL); + ZSTD_memcpy(dctx->headerBuffer + (dctx->headerSize - srcSize), src, srcSize); + FORWARD_IF_ERROR(ZSTD_decodeFrameHeader(dctx, dctx->headerBuffer, dctx->headerSize), ""); + dctx->expected = ZSTD_blockHeaderSize; + dctx->stage = ZSTDds_decodeBlockHeader; + return 0; + + case ZSTDds_decodeBlockHeader: + { blockProperties_t bp; + size_t const cBlockSize = ZSTD_getcBlockSize(src, ZSTD_blockHeaderSize, &bp); + if (ZSTD_isError(cBlockSize)) return cBlockSize; + RETURN_ERROR_IF(cBlockSize > dctx->fParams.blockSizeMax, corruption_detected, "Block Size Exceeds Maximum"); + dctx->expected = cBlockSize; + dctx->bType = bp.blockType; + dctx->rleSize = bp.origSize; + if (cBlockSize) { + dctx->stage = bp.lastBlock ? ZSTDds_decompressLastBlock : ZSTDds_decompressBlock; + return 0; + } + /* empty block */ + if (bp.lastBlock) { + if (dctx->fParams.checksumFlag) { + dctx->expected = 4; + dctx->stage = ZSTDds_checkChecksum; + } else { + dctx->expected = 0; /* end of frame */ + dctx->stage = ZSTDds_getFrameHeaderSize; + } + } else { + dctx->expected = ZSTD_blockHeaderSize; /* jump to next header */ + dctx->stage = ZSTDds_decodeBlockHeader; + } + return 0; + } + + case ZSTDds_decompressLastBlock: + case ZSTDds_decompressBlock: + DEBUGLOG(5, "ZSTD_decompressContinue: case ZSTDds_decompressBlock"); + { size_t rSize; + switch(dctx->bType) + { + case bt_compressed: + DEBUGLOG(5, "ZSTD_decompressContinue: case bt_compressed"); + rSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, /* frame */ 1, is_streaming); + dctx->expected = 0; /* Streaming not supported */ + break; + case bt_raw : + assert(srcSize <= dctx->expected); + rSize = ZSTD_copyRawBlock(dst, dstCapacity, src, srcSize); + FORWARD_IF_ERROR(rSize, "ZSTD_copyRawBlock failed"); + assert(rSize == srcSize); + dctx->expected -= rSize; + break; + case bt_rle : + rSize = ZSTD_setRleBlock(dst, dstCapacity, *(const BYTE*)src, dctx->rleSize); + dctx->expected = 0; /* Streaming not supported */ + break; + case bt_reserved : /* should never happen */ + default: + RETURN_ERROR(corruption_detected, "invalid block type"); + } + FORWARD_IF_ERROR(rSize, ""); + RETURN_ERROR_IF(rSize > dctx->fParams.blockSizeMax, corruption_detected, "Decompressed Block Size Exceeds Maximum"); + DEBUGLOG(5, "ZSTD_decompressContinue: decoded size from block : %u", (unsigned)rSize); + dctx->decodedSize += rSize; + if (dctx->validateChecksum) XXH64_update(&dctx->xxhState, dst, rSize); + dctx->previousDstEnd = (char*)dst + rSize; + + /* Stay on the same stage until we are finished streaming the block. */ + if (dctx->expected > 0) { + return rSize; + } + + if (dctx->stage == ZSTDds_decompressLastBlock) { /* end of frame */ + DEBUGLOG(4, "ZSTD_decompressContinue: decoded size from frame : %u", (unsigned)dctx->decodedSize); + RETURN_ERROR_IF( + dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN + && dctx->decodedSize != dctx->fParams.frameContentSize, + corruption_detected, ""); + if (dctx->fParams.checksumFlag) { /* another round for frame checksum */ + dctx->expected = 4; + dctx->stage = ZSTDds_checkChecksum; + } else { + ZSTD_DCtx_trace_end(dctx, dctx->decodedSize, dctx->processedCSize, /* streaming */ 1); + dctx->expected = 0; /* ends here */ + dctx->stage = ZSTDds_getFrameHeaderSize; + } + } else { + dctx->stage = ZSTDds_decodeBlockHeader; + dctx->expected = ZSTD_blockHeaderSize; + } + return rSize; + } + + case ZSTDds_checkChecksum: + assert(srcSize == 4); /* guaranteed by dctx->expected */ + { + if (dctx->validateChecksum) { + U32 const h32 = (U32)XXH64_digest(&dctx->xxhState); + U32 const check32 = MEM_readLE32(src); + DEBUGLOG(4, "ZSTD_decompressContinue: checksum : calculated %08X :: %08X read", (unsigned)h32, (unsigned)check32); + RETURN_ERROR_IF(check32 != h32, checksum_wrong, ""); + } + ZSTD_DCtx_trace_end(dctx, dctx->decodedSize, dctx->processedCSize, /* streaming */ 1); + dctx->expected = 0; + dctx->stage = ZSTDds_getFrameHeaderSize; + return 0; + } + + case ZSTDds_decodeSkippableHeader: + assert(src != NULL); + assert(srcSize <= ZSTD_SKIPPABLEHEADERSIZE); + ZSTD_memcpy(dctx->headerBuffer + (ZSTD_SKIPPABLEHEADERSIZE - srcSize), src, srcSize); /* complete skippable header */ + dctx->expected = MEM_readLE32(dctx->headerBuffer + ZSTD_FRAMEIDSIZE); /* note : dctx->expected can grow seriously large, beyond local buffer size */ + dctx->stage = ZSTDds_skipFrame; + return 0; + + case ZSTDds_skipFrame: + dctx->expected = 0; + dctx->stage = ZSTDds_getFrameHeaderSize; + return 0; + + default: + assert(0); /* impossible */ + RETURN_ERROR(GENERIC, "impossible to reach"); /* some compilers require default to do something */ + } +} + + +static size_t ZSTD_refDictContent(ZSTD_DCtx* dctx, const void* dict, size_t dictSize) +{ + dctx->dictEnd = dctx->previousDstEnd; + dctx->virtualStart = (const char*)dict - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->prefixStart)); + dctx->prefixStart = dict; + dctx->previousDstEnd = (const char*)dict + dictSize; +#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION + dctx->dictContentBeginForFuzzing = dctx->prefixStart; + dctx->dictContentEndForFuzzing = dctx->previousDstEnd; +#endif + return 0; +} + +/*! ZSTD_loadDEntropy() : + * dict : must point at beginning of a valid zstd dictionary. + * @return : size of entropy tables read */ +size_t +ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy, + const void* const dict, size_t const dictSize) +{ + const BYTE* dictPtr = (const BYTE*)dict; + const BYTE* const dictEnd = dictPtr + dictSize; + + RETURN_ERROR_IF(dictSize <= 8, dictionary_corrupted, "dict is too small"); + assert(MEM_readLE32(dict) == ZSTD_MAGIC_DICTIONARY); /* dict must be valid */ + dictPtr += 8; /* skip header = magic + dictID */ + + ZSTD_STATIC_ASSERT(offsetof(ZSTD_entropyDTables_t, OFTable) == offsetof(ZSTD_entropyDTables_t, LLTable) + sizeof(entropy->LLTable)); + ZSTD_STATIC_ASSERT(offsetof(ZSTD_entropyDTables_t, MLTable) == offsetof(ZSTD_entropyDTables_t, OFTable) + sizeof(entropy->OFTable)); + ZSTD_STATIC_ASSERT(sizeof(entropy->LLTable) + sizeof(entropy->OFTable) + sizeof(entropy->MLTable) >= HUF_DECOMPRESS_WORKSPACE_SIZE); + { void* const workspace = &entropy->LLTable; /* use fse tables as temporary workspace; implies fse tables are grouped together */ + size_t const workspaceSize = sizeof(entropy->LLTable) + sizeof(entropy->OFTable) + sizeof(entropy->MLTable); +#ifdef HUF_FORCE_DECOMPRESS_X1 + /* in minimal huffman, we always use X1 variants */ + size_t const hSize = HUF_readDTableX1_wksp(entropy->hufTable, + dictPtr, dictEnd - dictPtr, + workspace, workspaceSize, /* flags */ 0); +#else + size_t const hSize = HUF_readDTableX2_wksp(entropy->hufTable, + dictPtr, (size_t)(dictEnd - dictPtr), + workspace, workspaceSize, /* flags */ 0); +#endif + RETURN_ERROR_IF(HUF_isError(hSize), dictionary_corrupted, ""); + dictPtr += hSize; + } + + { short offcodeNCount[MaxOff+1]; + unsigned offcodeMaxValue = MaxOff, offcodeLog; + size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, &offcodeMaxValue, &offcodeLog, dictPtr, (size_t)(dictEnd-dictPtr)); + RETURN_ERROR_IF(FSE_isError(offcodeHeaderSize), dictionary_corrupted, ""); + RETURN_ERROR_IF(offcodeMaxValue > MaxOff, dictionary_corrupted, ""); + RETURN_ERROR_IF(offcodeLog > OffFSELog, dictionary_corrupted, ""); + ZSTD_buildFSETable( entropy->OFTable, + offcodeNCount, offcodeMaxValue, + OF_base, OF_bits, + offcodeLog, + entropy->workspace, sizeof(entropy->workspace), + /* bmi2 */0); + dictPtr += offcodeHeaderSize; + } + + { short matchlengthNCount[MaxML+1]; + unsigned matchlengthMaxValue = MaxML, matchlengthLog; + size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, (size_t)(dictEnd-dictPtr)); + RETURN_ERROR_IF(FSE_isError(matchlengthHeaderSize), dictionary_corrupted, ""); + RETURN_ERROR_IF(matchlengthMaxValue > MaxML, dictionary_corrupted, ""); + RETURN_ERROR_IF(matchlengthLog > MLFSELog, dictionary_corrupted, ""); + ZSTD_buildFSETable( entropy->MLTable, + matchlengthNCount, matchlengthMaxValue, + ML_base, ML_bits, + matchlengthLog, + entropy->workspace, sizeof(entropy->workspace), + /* bmi2 */ 0); + dictPtr += matchlengthHeaderSize; + } + + { short litlengthNCount[MaxLL+1]; + unsigned litlengthMaxValue = MaxLL, litlengthLog; + size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, (size_t)(dictEnd-dictPtr)); + RETURN_ERROR_IF(FSE_isError(litlengthHeaderSize), dictionary_corrupted, ""); + RETURN_ERROR_IF(litlengthMaxValue > MaxLL, dictionary_corrupted, ""); + RETURN_ERROR_IF(litlengthLog > LLFSELog, dictionary_corrupted, ""); + ZSTD_buildFSETable( entropy->LLTable, + litlengthNCount, litlengthMaxValue, + LL_base, LL_bits, + litlengthLog, + entropy->workspace, sizeof(entropy->workspace), + /* bmi2 */ 0); + dictPtr += litlengthHeaderSize; + } + + RETURN_ERROR_IF(dictPtr+12 > dictEnd, dictionary_corrupted, ""); + { int i; + size_t const dictContentSize = (size_t)(dictEnd - (dictPtr+12)); + for (i=0; i<3; i++) { + U32 const rep = MEM_readLE32(dictPtr); dictPtr += 4; + RETURN_ERROR_IF(rep==0 || rep > dictContentSize, + dictionary_corrupted, ""); + entropy->rep[i] = rep; + } } + + return (size_t)(dictPtr - (const BYTE*)dict); +} + +static size_t ZSTD_decompress_insertDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize) +{ + if (dictSize < 8) return ZSTD_refDictContent(dctx, dict, dictSize); + { U32 const magic = MEM_readLE32(dict); + if (magic != ZSTD_MAGIC_DICTIONARY) { + return ZSTD_refDictContent(dctx, dict, dictSize); /* pure content mode */ + } } + dctx->dictID = MEM_readLE32((const char*)dict + ZSTD_FRAMEIDSIZE); + + /* load entropy tables */ + { size_t const eSize = ZSTD_loadDEntropy(&dctx->entropy, dict, dictSize); + RETURN_ERROR_IF(ZSTD_isError(eSize), dictionary_corrupted, ""); + dict = (const char*)dict + eSize; + dictSize -= eSize; + } + dctx->litEntropy = dctx->fseEntropy = 1; + + /* reference dictionary content */ + return ZSTD_refDictContent(dctx, dict, dictSize); +} + +size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx) +{ + assert(dctx != NULL); +#if ZSTD_TRACE + dctx->traceCtx = (ZSTD_trace_decompress_begin != NULL) ? ZSTD_trace_decompress_begin(dctx) : 0; +#endif + dctx->expected = ZSTD_startingInputLength(dctx->format); /* dctx->format must be properly set */ + dctx->stage = ZSTDds_getFrameHeaderSize; + dctx->processedCSize = 0; + dctx->decodedSize = 0; + dctx->previousDstEnd = NULL; + dctx->prefixStart = NULL; + dctx->virtualStart = NULL; + dctx->dictEnd = NULL; + dctx->entropy.hufTable[0] = (HUF_DTable)((ZSTD_HUFFDTABLE_CAPACITY_LOG)*0x1000001); /* cover both little and big endian */ + dctx->litEntropy = dctx->fseEntropy = 0; + dctx->dictID = 0; + dctx->bType = bt_reserved; + ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.rep) == sizeof(repStartValue)); + ZSTD_memcpy(dctx->entropy.rep, repStartValue, sizeof(repStartValue)); /* initial repcodes */ + dctx->LLTptr = dctx->entropy.LLTable; + dctx->MLTptr = dctx->entropy.MLTable; + dctx->OFTptr = dctx->entropy.OFTable; + dctx->HUFptr = dctx->entropy.hufTable; + return 0; +} + +size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize) +{ + FORWARD_IF_ERROR( ZSTD_decompressBegin(dctx) , ""); + if (dict && dictSize) + RETURN_ERROR_IF( + ZSTD_isError(ZSTD_decompress_insertDictionary(dctx, dict, dictSize)), + dictionary_corrupted, ""); + return 0; +} + + +/* ====== ZSTD_DDict ====== */ + +size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict) +{ + DEBUGLOG(4, "ZSTD_decompressBegin_usingDDict"); + assert(dctx != NULL); + if (ddict) { + const char* const dictStart = (const char*)ZSTD_DDict_dictContent(ddict); + size_t const dictSize = ZSTD_DDict_dictSize(ddict); + const void* const dictEnd = dictStart + dictSize; + dctx->ddictIsCold = (dctx->dictEnd != dictEnd); + DEBUGLOG(4, "DDict is %s", + dctx->ddictIsCold ? "~cold~" : "hot!"); + } + FORWARD_IF_ERROR( ZSTD_decompressBegin(dctx) , ""); + if (ddict) { /* NULL ddict is equivalent to no dictionary */ + ZSTD_copyDDictParameters(dctx, ddict); + } + return 0; +} + +/*! ZSTD_getDictID_fromDict() : + * Provides the dictID stored within dictionary. + * if @return == 0, the dictionary is not conformant with Zstandard specification. + * It can still be loaded, but as a content-only dictionary. */ +unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize) +{ + if (dictSize < 8) return 0; + if (MEM_readLE32(dict) != ZSTD_MAGIC_DICTIONARY) return 0; + return MEM_readLE32((const char*)dict + ZSTD_FRAMEIDSIZE); +} + +/*! ZSTD_getDictID_fromFrame() : + * Provides the dictID required to decompress frame stored within `src`. + * If @return == 0, the dictID could not be decoded. + * This could for one of the following reasons : + * - The frame does not require a dictionary (most common case). + * - The frame was built with dictID intentionally removed. + * Needed dictionary is a hidden piece of information. + * Note : this use case also happens when using a non-conformant dictionary. + * - `srcSize` is too small, and as a result, frame header could not be decoded. + * Note : possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`. + * - This is not a Zstandard frame. + * When identifying the exact failure cause, it's possible to use + * ZSTD_getFrameHeader(), which will provide a more precise error code. */ +unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize) +{ + ZSTD_frameHeader zfp = { 0, 0, 0, ZSTD_frame, 0, 0, 0, 0, 0 }; + size_t const hError = ZSTD_getFrameHeader(&zfp, src, srcSize); + if (ZSTD_isError(hError)) return 0; + return zfp.dictID; +} + + +/*! ZSTD_decompress_usingDDict() : +* Decompression using a pre-digested Dictionary +* Use dictionary without significant overhead. */ +size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx, + void* dst, size_t dstCapacity, + const void* src, size_t srcSize, + const ZSTD_DDict* ddict) +{ + /* pass content and size in case legacy frames are encountered */ + return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize, + NULL, 0, + ddict); +} + + +/*===================================== +* Streaming decompression +*====================================*/ + +ZSTD_DStream* ZSTD_createDStream(void) +{ + DEBUGLOG(3, "ZSTD_createDStream"); + return ZSTD_createDCtx_internal(ZSTD_defaultCMem); +} + +ZSTD_DStream* ZSTD_initStaticDStream(void *workspace, size_t workspaceSize) +{ + return ZSTD_initStaticDCtx(workspace, workspaceSize); +} + +ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem) +{ + return ZSTD_createDCtx_internal(customMem); +} + +size_t ZSTD_freeDStream(ZSTD_DStream* zds) +{ + return ZSTD_freeDCtx(zds); +} + + +/* *** Initialization *** */ + +size_t ZSTD_DStreamInSize(void) { return ZSTD_BLOCKSIZE_MAX + ZSTD_blockHeaderSize; } +size_t ZSTD_DStreamOutSize(void) { return ZSTD_BLOCKSIZE_MAX; } + +size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, + const void* dict, size_t dictSize, + ZSTD_dictLoadMethod_e dictLoadMethod, + ZSTD_dictContentType_e dictContentType) +{ + RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, ""); + ZSTD_clearDict(dctx); + if (dict && dictSize != 0) { + dctx->ddictLocal = ZSTD_createDDict_advanced(dict, dictSize, dictLoadMethod, dictContentType, dctx->customMem); + RETURN_ERROR_IF(dctx->ddictLocal == NULL, memory_allocation, "NULL pointer!"); + dctx->ddict = dctx->ddictLocal; + dctx->dictUses = ZSTD_use_indefinitely; + } + return 0; +} + +size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize) +{ + return ZSTD_DCtx_loadDictionary_advanced(dctx, dict, dictSize, ZSTD_dlm_byRef, ZSTD_dct_auto); +} + +size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize) +{ + return ZSTD_DCtx_loadDictionary_advanced(dctx, dict, dictSize, ZSTD_dlm_byCopy, ZSTD_dct_auto); +} + +size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType) +{ + FORWARD_IF_ERROR(ZSTD_DCtx_loadDictionary_advanced(dctx, prefix, prefixSize, ZSTD_dlm_byRef, dictContentType), ""); + dctx->dictUses = ZSTD_use_once; + return 0; +} + +size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize) +{ + return ZSTD_DCtx_refPrefix_advanced(dctx, prefix, prefixSize, ZSTD_dct_rawContent); +} + + +/* ZSTD_initDStream_usingDict() : + * return : expected size, aka ZSTD_startingInputLength(). + * this function cannot fail */ +size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize) +{ + DEBUGLOG(4, "ZSTD_initDStream_usingDict"); + FORWARD_IF_ERROR( ZSTD_DCtx_reset(zds, ZSTD_reset_session_only) , ""); + FORWARD_IF_ERROR( ZSTD_DCtx_loadDictionary(zds, dict, dictSize) , ""); + return ZSTD_startingInputLength(zds->format); +} + +/* note : this variant can't fail */ +size_t ZSTD_initDStream(ZSTD_DStream* zds) +{ + DEBUGLOG(4, "ZSTD_initDStream"); + FORWARD_IF_ERROR(ZSTD_DCtx_reset(zds, ZSTD_reset_session_only), ""); + FORWARD_IF_ERROR(ZSTD_DCtx_refDDict(zds, NULL), ""); + return ZSTD_startingInputLength(zds->format); +} + +/* ZSTD_initDStream_usingDDict() : + * ddict will just be referenced, and must outlive decompression session + * this function cannot fail */ +size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* dctx, const ZSTD_DDict* ddict) +{ + DEBUGLOG(4, "ZSTD_initDStream_usingDDict"); + FORWARD_IF_ERROR( ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only) , ""); + FORWARD_IF_ERROR( ZSTD_DCtx_refDDict(dctx, ddict) , ""); + return ZSTD_startingInputLength(dctx->format); +} + +/* ZSTD_resetDStream() : + * return : expected size, aka ZSTD_startingInputLength(). + * this function cannot fail */ +size_t ZSTD_resetDStream(ZSTD_DStream* dctx) +{ + DEBUGLOG(4, "ZSTD_resetDStream"); + FORWARD_IF_ERROR(ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only), ""); + return ZSTD_startingInputLength(dctx->format); +} + + +size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict) +{ + RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, ""); + ZSTD_clearDict(dctx); + if (ddict) { + dctx->ddict = ddict; + dctx->dictUses = ZSTD_use_indefinitely; + if (dctx->refMultipleDDicts == ZSTD_rmd_refMultipleDDicts) { + if (dctx->ddictSet == NULL) { + dctx->ddictSet = ZSTD_createDDictHashSet(dctx->customMem); + if (!dctx->ddictSet) { + RETURN_ERROR(memory_allocation, "Failed to allocate memory for hash set!"); + } + } + assert(!dctx->staticSize); /* Impossible: ddictSet cannot have been allocated if static dctx */ + FORWARD_IF_ERROR(ZSTD_DDictHashSet_addDDict(dctx->ddictSet, ddict, dctx->customMem), ""); + } + } + return 0; +} + +/* ZSTD_DCtx_setMaxWindowSize() : + * note : no direct equivalence in ZSTD_DCtx_setParameter, + * since this version sets windowSize, and the other sets windowLog */ +size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize) +{ + ZSTD_bounds const bounds = ZSTD_dParam_getBounds(ZSTD_d_windowLogMax); + size_t const min = (size_t)1 << bounds.lowerBound; + size_t const max = (size_t)1 << bounds.upperBound; + RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, ""); + RETURN_ERROR_IF(maxWindowSize < min, parameter_outOfBound, ""); + RETURN_ERROR_IF(maxWindowSize > max, parameter_outOfBound, ""); + dctx->maxWindowSize = maxWindowSize; + return 0; +} + +size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format) +{ + return ZSTD_DCtx_setParameter(dctx, ZSTD_d_format, (int)format); +} + +ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam) +{ + ZSTD_bounds bounds = { 0, 0, 0 }; + switch(dParam) { + case ZSTD_d_windowLogMax: + bounds.lowerBound = ZSTD_WINDOWLOG_ABSOLUTEMIN; + bounds.upperBound = ZSTD_WINDOWLOG_MAX; + return bounds; + case ZSTD_d_format: + bounds.lowerBound = (int)ZSTD_f_zstd1; + bounds.upperBound = (int)ZSTD_f_zstd1_magicless; + ZSTD_STATIC_ASSERT(ZSTD_f_zstd1 < ZSTD_f_zstd1_magicless); + return bounds; + case ZSTD_d_stableOutBuffer: + bounds.lowerBound = (int)ZSTD_bm_buffered; + bounds.upperBound = (int)ZSTD_bm_stable; + return bounds; + case ZSTD_d_forceIgnoreChecksum: + bounds.lowerBound = (int)ZSTD_d_validateChecksum; + bounds.upperBound = (int)ZSTD_d_ignoreChecksum; + return bounds; + case ZSTD_d_refMultipleDDicts: + bounds.lowerBound = (int)ZSTD_rmd_refSingleDDict; + bounds.upperBound = (int)ZSTD_rmd_refMultipleDDicts; + return bounds; + case ZSTD_d_disableHuffmanAssembly: + bounds.lowerBound = 0; + bounds.upperBound = 1; + return bounds; + + default:; + } + bounds.error = ERROR(parameter_unsupported); + return bounds; +} + +/* ZSTD_dParam_withinBounds: + * @return 1 if value is within dParam bounds, + * 0 otherwise */ +static int ZSTD_dParam_withinBounds(ZSTD_dParameter dParam, int value) +{ + ZSTD_bounds const bounds = ZSTD_dParam_getBounds(dParam); + if (ZSTD_isError(bounds.error)) return 0; + if (value < bounds.lowerBound) return 0; + if (value > bounds.upperBound) return 0; + return 1; +} + +#define CHECK_DBOUNDS(p,v) { \ + RETURN_ERROR_IF(!ZSTD_dParam_withinBounds(p, v), parameter_outOfBound, ""); \ +} + +size_t ZSTD_DCtx_getParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int* value) +{ + switch (param) { + case ZSTD_d_windowLogMax: + *value = (int)ZSTD_highbit32((U32)dctx->maxWindowSize); + return 0; + case ZSTD_d_format: + *value = (int)dctx->format; + return 0; + case ZSTD_d_stableOutBuffer: + *value = (int)dctx->outBufferMode; + return 0; + case ZSTD_d_forceIgnoreChecksum: + *value = (int)dctx->forceIgnoreChecksum; + return 0; + case ZSTD_d_refMultipleDDicts: + *value = (int)dctx->refMultipleDDicts; + return 0; + case ZSTD_d_disableHuffmanAssembly: + *value = (int)dctx->disableHufAsm; + return 0; + default:; + } + RETURN_ERROR(parameter_unsupported, ""); +} + +size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter dParam, int value) +{ + RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, ""); + switch(dParam) { + case ZSTD_d_windowLogMax: + if (value == 0) value = ZSTD_WINDOWLOG_LIMIT_DEFAULT; + CHECK_DBOUNDS(ZSTD_d_windowLogMax, value); + dctx->maxWindowSize = ((size_t)1) << value; + return 0; + case ZSTD_d_format: + CHECK_DBOUNDS(ZSTD_d_format, value); + dctx->format = (ZSTD_format_e)value; + return 0; + case ZSTD_d_stableOutBuffer: + CHECK_DBOUNDS(ZSTD_d_stableOutBuffer, value); + dctx->outBufferMode = (ZSTD_bufferMode_e)value; + return 0; + case ZSTD_d_forceIgnoreChecksum: + CHECK_DBOUNDS(ZSTD_d_forceIgnoreChecksum, value); + dctx->forceIgnoreChecksum = (ZSTD_forceIgnoreChecksum_e)value; + return 0; + case ZSTD_d_refMultipleDDicts: + CHECK_DBOUNDS(ZSTD_d_refMultipleDDicts, value); + if (dctx->staticSize != 0) { + RETURN_ERROR(parameter_unsupported, "Static dctx does not support multiple DDicts!"); + } + dctx->refMultipleDDicts = (ZSTD_refMultipleDDicts_e)value; + return 0; + case ZSTD_d_disableHuffmanAssembly: + CHECK_DBOUNDS(ZSTD_d_disableHuffmanAssembly, value); + dctx->disableHufAsm = value != 0; + return 0; + default:; + } + RETURN_ERROR(parameter_unsupported, ""); +} + +size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset) +{ + if ( (reset == ZSTD_reset_session_only) + || (reset == ZSTD_reset_session_and_parameters) ) { + dctx->streamStage = zdss_init; + dctx->noForwardProgress = 0; + } + if ( (reset == ZSTD_reset_parameters) + || (reset == ZSTD_reset_session_and_parameters) ) { + RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, ""); + ZSTD_clearDict(dctx); + ZSTD_DCtx_resetParameters(dctx); + } + return 0; +} + + +size_t ZSTD_sizeof_DStream(const ZSTD_DStream* dctx) +{ + return ZSTD_sizeof_DCtx(dctx); +} + +size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long long frameContentSize) +{ + size_t const blockSize = (size_t) MIN(windowSize, ZSTD_BLOCKSIZE_MAX); + /* space is needed to store the litbuffer after the output of a given block without stomping the extDict of a previous run, as well as to cover both windows against wildcopy*/ + unsigned long long const neededRBSize = windowSize + blockSize + ZSTD_BLOCKSIZE_MAX + (WILDCOPY_OVERLENGTH * 2); + unsigned long long const neededSize = MIN(frameContentSize, neededRBSize); + size_t const minRBSize = (size_t) neededSize; + RETURN_ERROR_IF((unsigned long long)minRBSize != neededSize, + frameParameter_windowTooLarge, ""); + return minRBSize; +} + +size_t ZSTD_estimateDStreamSize(size_t windowSize) +{ + size_t const blockSize = MIN(windowSize, ZSTD_BLOCKSIZE_MAX); + size_t const inBuffSize = blockSize; /* no block can be larger */ + size_t const outBuffSize = ZSTD_decodingBufferSize_min(windowSize, ZSTD_CONTENTSIZE_UNKNOWN); + return ZSTD_estimateDCtxSize() + inBuffSize + outBuffSize; +} + +size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize) +{ + U32 const windowSizeMax = 1U << ZSTD_WINDOWLOG_MAX; /* note : should be user-selectable, but requires an additional parameter (or a dctx) */ + ZSTD_frameHeader zfh; + size_t const err = ZSTD_getFrameHeader(&zfh, src, srcSize); + if (ZSTD_isError(err)) return err; + RETURN_ERROR_IF(err>0, srcSize_wrong, ""); + RETURN_ERROR_IF(zfh.windowSize > windowSizeMax, + frameParameter_windowTooLarge, ""); + return ZSTD_estimateDStreamSize((size_t)zfh.windowSize); +} + + +/* ***** Decompression ***** */ + +static int ZSTD_DCtx_isOverflow(ZSTD_DStream* zds, size_t const neededInBuffSize, size_t const neededOutBuffSize) +{ + return (zds->inBuffSize + zds->outBuffSize) >= (neededInBuffSize + neededOutBuffSize) * ZSTD_WORKSPACETOOLARGE_FACTOR; +} + +static void ZSTD_DCtx_updateOversizedDuration(ZSTD_DStream* zds, size_t const neededInBuffSize, size_t const neededOutBuffSize) +{ + if (ZSTD_DCtx_isOverflow(zds, neededInBuffSize, neededOutBuffSize)) + zds->oversizedDuration++; + else + zds->oversizedDuration = 0; +} + +static int ZSTD_DCtx_isOversizedTooLong(ZSTD_DStream* zds) +{ + return zds->oversizedDuration >= ZSTD_WORKSPACETOOLARGE_MAXDURATION; +} + +/* Checks that the output buffer hasn't changed if ZSTD_obm_stable is used. */ +static size_t ZSTD_checkOutBuffer(ZSTD_DStream const* zds, ZSTD_outBuffer const* output) +{ + ZSTD_outBuffer const expect = zds->expectedOutBuffer; + /* No requirement when ZSTD_obm_stable is not enabled. */ + if (zds->outBufferMode != ZSTD_bm_stable) + return 0; + /* Any buffer is allowed in zdss_init, this must be the same for every other call until + * the context is reset. + */ + if (zds->streamStage == zdss_init) + return 0; + /* The buffer must match our expectation exactly. */ + if (expect.dst == output->dst && expect.pos == output->pos && expect.size == output->size) + return 0; + RETURN_ERROR(dstBuffer_wrong, "ZSTD_d_stableOutBuffer enabled but output differs!"); +} + +/* Calls ZSTD_decompressContinue() with the right parameters for ZSTD_decompressStream() + * and updates the stage and the output buffer state. This call is extracted so it can be + * used both when reading directly from the ZSTD_inBuffer, and in buffered input mode. + * NOTE: You must break after calling this function since the streamStage is modified. + */ +static size_t ZSTD_decompressContinueStream( + ZSTD_DStream* zds, char** op, char* oend, + void const* src, size_t srcSize) { + int const isSkipFrame = ZSTD_isSkipFrame(zds); + if (zds->outBufferMode == ZSTD_bm_buffered) { + size_t const dstSize = isSkipFrame ? 0 : zds->outBuffSize - zds->outStart; + size_t const decodedSize = ZSTD_decompressContinue(zds, + zds->outBuff + zds->outStart, dstSize, src, srcSize); + FORWARD_IF_ERROR(decodedSize, ""); + if (!decodedSize && !isSkipFrame) { + zds->streamStage = zdss_read; + } else { + zds->outEnd = zds->outStart + decodedSize; + zds->streamStage = zdss_flush; + } + } else { + /* Write directly into the output buffer */ + size_t const dstSize = isSkipFrame ? 0 : (size_t)(oend - *op); + size_t const decodedSize = ZSTD_decompressContinue(zds, *op, dstSize, src, srcSize); + FORWARD_IF_ERROR(decodedSize, ""); + *op += decodedSize; + /* Flushing is not needed. */ + zds->streamStage = zdss_read; + assert(*op <= oend); + assert(zds->outBufferMode == ZSTD_bm_stable); + } + return 0; +} + +size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input) +{ + const char* const src = (const char*)input->src; + const char* const istart = input->pos != 0 ? src + input->pos : src; + const char* const iend = input->size != 0 ? src + input->size : src; + const char* ip = istart; + char* const dst = (char*)output->dst; + char* const ostart = output->pos != 0 ? dst + output->pos : dst; + char* const oend = output->size != 0 ? dst + output->size : dst; + char* op = ostart; + U32 someMoreWork = 1; + + DEBUGLOG(5, "ZSTD_decompressStream"); + RETURN_ERROR_IF( + input->pos > input->size, + srcSize_wrong, + "forbidden. in: pos: %u vs size: %u", + (U32)input->pos, (U32)input->size); + RETURN_ERROR_IF( + output->pos > output->size, + dstSize_tooSmall, + "forbidden. out: pos: %u vs size: %u", + (U32)output->pos, (U32)output->size); + DEBUGLOG(5, "input size : %u", (U32)(input->size - input->pos)); + FORWARD_IF_ERROR(ZSTD_checkOutBuffer(zds, output), ""); + + while (someMoreWork) { + switch(zds->streamStage) + { + case zdss_init : + DEBUGLOG(5, "stage zdss_init => transparent reset "); + zds->streamStage = zdss_loadHeader; + zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0; +#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1) + zds->legacyVersion = 0; +#endif + zds->hostageByte = 0; + zds->expectedOutBuffer = *output; + ZSTD_FALLTHROUGH; + + case zdss_loadHeader : + DEBUGLOG(5, "stage zdss_loadHeader (srcSize : %u)", (U32)(iend - ip)); +#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1) + if (zds->legacyVersion) { + RETURN_ERROR_IF(zds->staticSize, memory_allocation, + "legacy support is incompatible with static dctx"); + { size_t const hint = ZSTD_decompressLegacyStream(zds->legacyContext, zds->legacyVersion, output, input); + if (hint==0) zds->streamStage = zdss_init; + return hint; + } } +#endif + { size_t const hSize = ZSTD_getFrameHeader_advanced(&zds->fParams, zds->headerBuffer, zds->lhSize, zds->format); + if (zds->refMultipleDDicts && zds->ddictSet) { + ZSTD_DCtx_selectFrameDDict(zds); + } + if (ZSTD_isError(hSize)) { +#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1) + U32 const legacyVersion = ZSTD_isLegacy(istart, iend-istart); + if (legacyVersion) { + ZSTD_DDict const* const ddict = ZSTD_getDDict(zds); + const void* const dict = ddict ? ZSTD_DDict_dictContent(ddict) : NULL; + size_t const dictSize = ddict ? ZSTD_DDict_dictSize(ddict) : 0; + DEBUGLOG(5, "ZSTD_decompressStream: detected legacy version v0.%u", legacyVersion); + RETURN_ERROR_IF(zds->staticSize, memory_allocation, + "legacy support is incompatible with static dctx"); + FORWARD_IF_ERROR(ZSTD_initLegacyStream(&zds->legacyContext, + zds->previousLegacyVersion, legacyVersion, + dict, dictSize), ""); + zds->legacyVersion = zds->previousLegacyVersion = legacyVersion; + { size_t const hint = ZSTD_decompressLegacyStream(zds->legacyContext, legacyVersion, output, input); + if (hint==0) zds->streamStage = zdss_init; /* or stay in stage zdss_loadHeader */ + return hint; + } } +#endif + return hSize; /* error */ + } + if (hSize != 0) { /* need more input */ + size_t const toLoad = hSize - zds->lhSize; /* if hSize!=0, hSize > zds->lhSize */ + size_t const remainingInput = (size_t)(iend-ip); + assert(iend >= ip); + if (toLoad > remainingInput) { /* not enough input to load full header */ + if (remainingInput > 0) { + ZSTD_memcpy(zds->headerBuffer + zds->lhSize, ip, remainingInput); + zds->lhSize += remainingInput; + } + input->pos = input->size; + /* check first few bytes */ + FORWARD_IF_ERROR( + ZSTD_getFrameHeader_advanced(&zds->fParams, zds->headerBuffer, zds->lhSize, zds->format), + "First few bytes detected incorrect" ); + /* return hint input size */ + return (MAX((size_t)ZSTD_FRAMEHEADERSIZE_MIN(zds->format), hSize) - zds->lhSize) + ZSTD_blockHeaderSize; /* remaining header bytes + next block header */ + } + assert(ip != NULL); + ZSTD_memcpy(zds->headerBuffer + zds->lhSize, ip, toLoad); zds->lhSize = hSize; ip += toLoad; + break; + } } + + /* check for single-pass mode opportunity */ + if (zds->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN + && zds->fParams.frameType != ZSTD_skippableFrame + && (U64)(size_t)(oend-op) >= zds->fParams.frameContentSize) { + size_t const cSize = ZSTD_findFrameCompressedSize(istart, (size_t)(iend-istart)); + if (cSize <= (size_t)(iend-istart)) { + /* shortcut : using single-pass mode */ + size_t const decompressedSize = ZSTD_decompress_usingDDict(zds, op, (size_t)(oend-op), istart, cSize, ZSTD_getDDict(zds)); + if (ZSTD_isError(decompressedSize)) return decompressedSize; + DEBUGLOG(4, "shortcut to single-pass ZSTD_decompress_usingDDict()") + assert(istart != NULL); + ip = istart + cSize; + op = op ? op + decompressedSize : op; /* can occur if frameContentSize = 0 (empty frame) */ + zds->expected = 0; + zds->streamStage = zdss_init; + someMoreWork = 0; + break; + } } + + /* Check output buffer is large enough for ZSTD_odm_stable. */ + if (zds->outBufferMode == ZSTD_bm_stable + && zds->fParams.frameType != ZSTD_skippableFrame + && zds->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN + && (U64)(size_t)(oend-op) < zds->fParams.frameContentSize) { + RETURN_ERROR(dstSize_tooSmall, "ZSTD_obm_stable passed but ZSTD_outBuffer is too small"); + } + + /* Consume header (see ZSTDds_decodeFrameHeader) */ + DEBUGLOG(4, "Consume header"); + FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(zds, ZSTD_getDDict(zds)), ""); + + if ((MEM_readLE32(zds->headerBuffer) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */ + zds->expected = MEM_readLE32(zds->headerBuffer + ZSTD_FRAMEIDSIZE); + zds->stage = ZSTDds_skipFrame; + } else { + FORWARD_IF_ERROR(ZSTD_decodeFrameHeader(zds, zds->headerBuffer, zds->lhSize), ""); + zds->expected = ZSTD_blockHeaderSize; + zds->stage = ZSTDds_decodeBlockHeader; + } + + /* control buffer memory usage */ + DEBUGLOG(4, "Control max memory usage (%u KB <= max %u KB)", + (U32)(zds->fParams.windowSize >>10), + (U32)(zds->maxWindowSize >> 10) ); + zds->fParams.windowSize = MAX(zds->fParams.windowSize, 1U << ZSTD_WINDOWLOG_ABSOLUTEMIN); + RETURN_ERROR_IF(zds->fParams.windowSize > zds->maxWindowSize, + frameParameter_windowTooLarge, ""); + + /* Adapt buffer sizes to frame header instructions */ + { size_t const neededInBuffSize = MAX(zds->fParams.blockSizeMax, 4 /* frame checksum */); + size_t const neededOutBuffSize = zds->outBufferMode == ZSTD_bm_buffered + ? ZSTD_decodingBufferSize_min(zds->fParams.windowSize, zds->fParams.frameContentSize) + : 0; + + ZSTD_DCtx_updateOversizedDuration(zds, neededInBuffSize, neededOutBuffSize); + + { int const tooSmall = (zds->inBuffSize < neededInBuffSize) || (zds->outBuffSize < neededOutBuffSize); + int const tooLarge = ZSTD_DCtx_isOversizedTooLong(zds); + + if (tooSmall || tooLarge) { + size_t const bufferSize = neededInBuffSize + neededOutBuffSize; + DEBUGLOG(4, "inBuff : from %u to %u", + (U32)zds->inBuffSize, (U32)neededInBuffSize); + DEBUGLOG(4, "outBuff : from %u to %u", + (U32)zds->outBuffSize, (U32)neededOutBuffSize); + if (zds->staticSize) { /* static DCtx */ + DEBUGLOG(4, "staticSize : %u", (U32)zds->staticSize); + assert(zds->staticSize >= sizeof(ZSTD_DCtx)); /* controlled at init */ + RETURN_ERROR_IF( + bufferSize > zds->staticSize - sizeof(ZSTD_DCtx), + memory_allocation, ""); + } else { + ZSTD_customFree(zds->inBuff, zds->customMem); + zds->inBuffSize = 0; + zds->outBuffSize = 0; + zds->inBuff = (char*)ZSTD_customMalloc(bufferSize, zds->customMem); + RETURN_ERROR_IF(zds->inBuff == NULL, memory_allocation, ""); + } + zds->inBuffSize = neededInBuffSize; + zds->outBuff = zds->inBuff + zds->inBuffSize; + zds->outBuffSize = neededOutBuffSize; + } } } + zds->streamStage = zdss_read; + ZSTD_FALLTHROUGH; + + case zdss_read: + DEBUGLOG(5, "stage zdss_read"); + { size_t const neededInSize = ZSTD_nextSrcSizeToDecompressWithInputSize(zds, (size_t)(iend - ip)); + DEBUGLOG(5, "neededInSize = %u", (U32)neededInSize); + if (neededInSize==0) { /* end of frame */ + zds->streamStage = zdss_init; + someMoreWork = 0; + break; + } + if ((size_t)(iend-ip) >= neededInSize) { /* decode directly from src */ + FORWARD_IF_ERROR(ZSTD_decompressContinueStream(zds, &op, oend, ip, neededInSize), ""); + assert(ip != NULL); + ip += neededInSize; + /* Function modifies the stage so we must break */ + break; + } } + if (ip==iend) { someMoreWork = 0; break; } /* no more input */ + zds->streamStage = zdss_load; + ZSTD_FALLTHROUGH; + + case zdss_load: + { size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds); + size_t const toLoad = neededInSize - zds->inPos; + int const isSkipFrame = ZSTD_isSkipFrame(zds); + size_t loadedSize; + /* At this point we shouldn't be decompressing a block that we can stream. */ + assert(neededInSize == ZSTD_nextSrcSizeToDecompressWithInputSize(zds, (size_t)(iend - ip))); + if (isSkipFrame) { + loadedSize = MIN(toLoad, (size_t)(iend-ip)); + } else { + RETURN_ERROR_IF(toLoad > zds->inBuffSize - zds->inPos, + corruption_detected, + "should never happen"); + loadedSize = ZSTD_limitCopy(zds->inBuff + zds->inPos, toLoad, ip, (size_t)(iend-ip)); + } + if (loadedSize != 0) { + /* ip may be NULL */ + ip += loadedSize; + zds->inPos += loadedSize; + } + if (loadedSize < toLoad) { someMoreWork = 0; break; } /* not enough input, wait for more */ + + /* decode loaded input */ + zds->inPos = 0; /* input is consumed */ + FORWARD_IF_ERROR(ZSTD_decompressContinueStream(zds, &op, oend, zds->inBuff, neededInSize), ""); + /* Function modifies the stage so we must break */ + break; + } + case zdss_flush: + { + size_t const toFlushSize = zds->outEnd - zds->outStart; + size_t const flushedSize = ZSTD_limitCopy(op, (size_t)(oend-op), zds->outBuff + zds->outStart, toFlushSize); + + op = op ? op + flushedSize : op; + + zds->outStart += flushedSize; + if (flushedSize == toFlushSize) { /* flush completed */ + zds->streamStage = zdss_read; + if ( (zds->outBuffSize < zds->fParams.frameContentSize) + && (zds->outStart + zds->fParams.blockSizeMax > zds->outBuffSize) ) { + DEBUGLOG(5, "restart filling outBuff from beginning (left:%i, needed:%u)", + (int)(zds->outBuffSize - zds->outStart), + (U32)zds->fParams.blockSizeMax); + zds->outStart = zds->outEnd = 0; + } + break; + } } + /* cannot complete flush */ + someMoreWork = 0; + break; + + default: + assert(0); /* impossible */ + RETURN_ERROR(GENERIC, "impossible to reach"); /* some compilers require default to do something */ + } } + + /* result */ + input->pos = (size_t)(ip - (const char*)(input->src)); + output->pos = (size_t)(op - (char*)(output->dst)); + + /* Update the expected output buffer for ZSTD_obm_stable. */ + zds->expectedOutBuffer = *output; + + if ((ip==istart) && (op==ostart)) { /* no forward progress */ + zds->noForwardProgress ++; + if (zds->noForwardProgress >= ZSTD_NO_FORWARD_PROGRESS_MAX) { + RETURN_ERROR_IF(op==oend, noForwardProgress_destFull, ""); + RETURN_ERROR_IF(ip==iend, noForwardProgress_inputEmpty, ""); + assert(0); + } + } else { + zds->noForwardProgress = 0; + } + { size_t nextSrcSizeHint = ZSTD_nextSrcSizeToDecompress(zds); + if (!nextSrcSizeHint) { /* frame fully decoded */ + if (zds->outEnd == zds->outStart) { /* output fully flushed */ + if (zds->hostageByte) { + if (input->pos >= input->size) { + /* can't release hostage (not present) */ + zds->streamStage = zdss_read; + return 1; + } + input->pos++; /* release hostage */ + } /* zds->hostageByte */ + return 0; + } /* zds->outEnd == zds->outStart */ + if (!zds->hostageByte) { /* output not fully flushed; keep last byte as hostage; will be released when all output is flushed */ + input->pos--; /* note : pos > 0, otherwise, impossible to finish reading last block */ + zds->hostageByte=1; + } + return 1; + } /* nextSrcSizeHint==0 */ + nextSrcSizeHint += ZSTD_blockHeaderSize * (ZSTD_nextInputType(zds) == ZSTDnit_block); /* preload header of next block */ + assert(zds->inPos <= nextSrcSizeHint); + nextSrcSizeHint -= zds->inPos; /* part already loaded*/ + return nextSrcSizeHint; + } +} + +size_t ZSTD_decompressStream_simpleArgs ( + ZSTD_DCtx* dctx, + void* dst, size_t dstCapacity, size_t* dstPos, + const void* src, size_t srcSize, size_t* srcPos) +{ + ZSTD_outBuffer output; + ZSTD_inBuffer input; + output.dst = dst; + output.size = dstCapacity; + output.pos = *dstPos; + input.src = src; + input.size = srcSize; + input.pos = *srcPos; + { size_t const cErr = ZSTD_decompressStream(dctx, &output, &input); + *dstPos = output.pos; + *srcPos = input.pos; + return cErr; + } +} |