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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /*
  * Copyright (c) Yann Collet, Facebook, Inc.
  * 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+)
 */
 
 /*!
  *  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 "../common/zstd_deps.h"   /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */
 #include "../common/cpu.h"         /* bmi2 */
 #include "../common/mem.h"         /* low level memory routines */
 #define FSE_STATIC_LINKING_ONLY
 #include "../common/fse.h"
 #define HUF_STATIC_LINKING_ONLY
 #include "../common/huf.h"
 #include <linux/xxhash.h> /* xxh64_reset, xxh64_update, xxh64_digest, XXH64 */
 #include "../common/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 */
 
 
 
 
 /* ***********************************
  * 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;
 }
 
 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;
     dctx->legacyContext = NULL;
     dctx->previousLegacyVersion = 0;
     dctx->noForwardProgress = 0;
     dctx->oversizedDuration = 0;
     dctx->bmi2 = ZSTD_cpuid_bmi2(ZSTD_cpuid());
     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;
 }
 
 ZSTD_DCtx* ZSTD_createDCtx_advanced(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(void)
 {
     DEBUGLOG(3, "ZSTD_createDCtx");
     return ZSTD_createDCtx_advanced(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 (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;
     }
     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);
 
     ZSTD_memset(zfhPtr, 0, sizeof(*zfhPtr));   /* not strictly necessary, but static analyzer do not understand that zfhPtr is only going to be read only if return value is zero, since they are 2 different signals */
     if (srcSize < minInputSize) return minInputSize;
     RETURN_ERROR_IF(src==NULL, GENERIC, "invalid parameter");
 
     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)
 {
     {   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_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 ((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.compressedSize = (size_t)(ip - ipstart);
         frameSizeInfo.decompressedBound = (zfh.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN)
                                         ? zfh.frameContentSize
                                         : 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;
 }
 
 
 /*-*************************************************************
  *   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_memcpy(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)
 {
     (void)dctx;
     (void)uncompressedSize;
     (void)compressedSize;
     (void)streaming;
 }
 
 
 /*! 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) {
         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, "");
 
         switch(blockProperties.blockType)
         {
         case bt_compressed:
             decodedSize = ZSTD_decompressBlock_internal(dctx, op, (size_t)(oend-op), ip, cBlockSize, /* frame */ 1);
             break;
         case bt_raw :
             decodedSize = ZSTD_copyRawBlock(op, (size_t)(oend-op), ip, cBlockSize);
             break;
         case bt_rle :
             decodedSize = ZSTD_setRleBlock(op, (size_t)(oend-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 */
     *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)) {
 
 
         {   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();
     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 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 MIN(MAX(inputSize, 1), 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);
                 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 compiler 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);
 #else
         size_t const hSize = HUF_readDTableX2_wksp(entropy->hufTable,
                                                 dictPtr, (size_t)(dictEnd - dictPtr),
                                                 workspace, workspaceSize);
 #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);
     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)((HufLog)*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 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 };
     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_createDStream_advanced(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_advanced(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");
     return ZSTD_initDStream_usingDDict(zds, NULL);
 }
 
 /* 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)
 {
     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)
 {
     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;
         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;
         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;
         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);
     unsigned long long const neededRBSize = windowSize + blockSize + (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;
             zds->legacyVersion = 0;
             zds->hostageByte = 0;
             zds->expectedOutBuffer = *output;
             ZSTD_FALLTHROUGH;
 
         case zdss_loadHeader :
             DEBUGLOG(5, "stage zdss_loadHeader (srcSize : %u)", (U32)(iend - ip));
             {   size_t const hSize = ZSTD_getFrameHeader_advanced(&zds->fParams, zds->headerBuffer, zds->lhSize, zds->format);
                 if (zds->refMultipleDDicts && zds->ddictSet) {
                     ZSTD_DCtx_selectFrameDDict(zds);
                 }
                 DEBUGLOG(5, "header size : %u", (U32)hSize);
                 if (ZSTD_isError(hSize)) {
                     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;
                         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()")
                     ip = istart + cSize;
                     op += decompressedSize;
                     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), "");
                     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, 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));
                 }
                 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 += flushedSize;
                 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 compiler 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, dstSize_tooSmall, "");
             RETURN_ERROR_IF(ip==iend, srcSize_wrong, "");
             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 = { dst, dstCapacity, *dstPos };
     ZSTD_inBuffer  input  = { src, srcSize, *srcPos };
     /* ZSTD_compress_generic() will check validity of dstPos and srcPos */
     size_t const cErr = ZSTD_decompressStream(dctx, &output, &input);
     *dstPos = output.pos;
     *srcPos = input.pos;
     return cErr;
 }

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