chromium/third_party/zstd/src/lib/decompress/zstd_decompress.c

/*
 * 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 …
#endif

/*!
*  LEGACY_SUPPORT :
*  if set to 1+, ZSTD_decompress() can decode older formats (v0.1+)
*/
#ifndef ZSTD_LEGACY_SUPPORT
#define ZSTD_LEGACY_SUPPORT …
#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 …
#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 …
#endif


/*-*******************************************************
*  Dependencies
*********************************************************/
#include "../common/zstd_deps.h"   /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */
#include "../common/allocations.h"  /* ZSTD_customMalloc, ZSTD_customCalloc, ZSTD_customFree */
#include "../common/error_private.h"
#include "../common/zstd_internal.h"  /* blockProperties_t */
#include "../common/mem.h"         /* low level memory routines */
#include "../common/bits.h"  /* ZSTD_highbit32 */
#define FSE_STATIC_LINKING_ONLY
#include "../common/fse.h"
#include "../common/huf.h"
#include "../common/xxhash.h" /* XXH64_reset, XXH64_update, XXH64_digest, XXH64 */
#include "zstd_decompress_internal.h"   /* ZSTD_DCtx */
#include "zstd_ddict.h"  /* ZSTD_DDictDictContent */
#include "zstd_decompress_block.h"   /* ZSTD_decompressBlock_internal */

#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 …
#define DDICT_HASHSET_MAX_LOAD_FACTOR_SIZE_MULT …

#define DDICT_HASHSET_TABLE_BASE_SIZE …
#define DDICT_HASHSET_RESIZE_FACTOR …

/* 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) { … }

/* 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) { … }

/* 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) { … }

/* 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) { … }

/* 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) { … }

/* 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) { … }

/* 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) { … }

/*-*************************************************************
*   Context management
***************************************************************/
size_t ZSTD_sizeof_DCtx (const ZSTD_DCtx* dctx)
{ … }

size_t ZSTD_estimateDCtxSize(void) { … }


static size_t ZSTD_startingInputLength(ZSTD_format_e format)
{ … }

static void ZSTD_DCtx_resetParameters(ZSTD_DCtx* dctx)
{ … }

static void ZSTD_initDCtx_internal(ZSTD_DCtx* dctx)
{ … }

ZSTD_DCtx* ZSTD_initStaticDCtx(void *workspace, size_t workspaceSize)
{ … }

static ZSTD_DCtx* ZSTD_createDCtx_internal(ZSTD_customMem customMem) { … }

ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem)
{ … }

ZSTD_DCtx* ZSTD_createDCtx(void)
{ … }

static void ZSTD_clearDict(ZSTD_DCtx* dctx)
{ … }

size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx)
{ … }

/* no longer useful */
void ZSTD_copyDCtx(ZSTD_DCtx* dstDCtx, const ZSTD_DCtx* srcDCtx)
{ … }

/* 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) { … }


/*-*************************************************************
 *   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)
{ … }

/*! 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)
{ … }

/** 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)
{ … }

/** 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)
{ … }


/** 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)
{ … }

/** 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)
{ … }

/** 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)
{ … }

static size_t readSkippableFrameSize(void const* src, size_t srcSize)
{ … }

/*! ZSTD_readSkippableFrame() :
 * Retrieves content of a skippable frame, 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 this is not a valid skippable frame.
 *
 * @return : number of bytes written or a ZSTD error.
 */
size_t ZSTD_readSkippableFrame(void* dst, size_t dstCapacity,
                               unsigned* magicVariant,  /* optional, can be NULL */
                         const void* src, size_t srcSize)
{ … }

/** ZSTD_findDecompressedSize() :
 *  `srcSize` must be the exact length of some number of ZSTD compressed and/or
 *      skippable frames
 *  note: compatible with legacy mode
 * @return : decompressed size of the frames contained */
unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize)
{ … }

/** 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)
{ … }


/** 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)
{ … }

static ZSTD_frameSizeInfo ZSTD_errorFrameSizeInfo(size_t ret)
{ … }

static ZSTD_frameSizeInfo ZSTD_findFrameSizeInfo(const void* src, size_t srcSize, ZSTD_format_e format)
{ … }

static size_t ZSTD_findFrameCompressedSize_advanced(const void *src, size_t srcSize, ZSTD_format_e format) { … }

/** ZSTD_findFrameCompressedSize() :
 * See docs in zstd.h
 * Note: compatible with legacy mode */
size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize)
{ … }

/** ZSTD_decompressBound() :
 *  compatible with legacy mode
 *  `src` must point to the start of a ZSTD frame or a skippable 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)
{ … }

size_t ZSTD_decompressionMargin(void const* src, size_t srcSize)
{ … }

/*-*************************************************************
 *   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)
{ … }


static size_t ZSTD_copyRawBlock(void* dst, size_t dstCapacity,
                          const void* src, size_t srcSize)
{ … }

static size_t ZSTD_setRleBlock(void* dst, size_t dstCapacity,
                               BYTE b,
                               size_t regenSize)
{ … }

static void ZSTD_DCtx_trace_end(ZSTD_DCtx const* dctx, U64 uncompressedSize, U64 compressedSize, unsigned 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)
{ … }

static
ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
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)
{ … }

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)
{ … }


static ZSTD_DDict const* ZSTD_getDDict(ZSTD_DCtx* dctx)
{ … }

size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{ … }


size_t ZSTD_decompress(void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{ … }


/*-**************************************
*   Advanced Streaming Decompression API
*   Bufferless and synchronous
****************************************/
size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx) { … }

/**
 * 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) { … }

ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx) { … }

static int ZSTD_isSkipFrame(ZSTD_DCtx* dctx) { … }

/** 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)
{ … }


static size_t ZSTD_refDictContent(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
{ … }

/*! 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)
{ … }

static size_t ZSTD_decompress_insertDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
{ … }

size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx)
{ … }

size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
{ … }


/* ======   ZSTD_DDict   ====== */

size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
{ … }

/*! 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)
{ … }

/*! 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_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)
{ … }


/*=====================================
*   Streaming decompression
*====================================*/

ZSTD_DStream* ZSTD_createDStream(void)
{ … }

ZSTD_DStream* ZSTD_initStaticDStream(void *workspace, size_t workspaceSize)
{ … }

ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem)
{ … }

size_t ZSTD_freeDStream(ZSTD_DStream* zds)
{ … }


/* ***  Initialization  *** */

size_t ZSTD_DStreamInSize(void)  { … }
size_t ZSTD_DStreamOutSize(void) { … }

size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx,
                                   const void* dict, size_t dictSize,
                                         ZSTD_dictLoadMethod_e dictLoadMethod,
                                         ZSTD_dictContentType_e dictContentType)
{ … }

size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
{ … }

size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
{ … }

size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType)
{ … }

size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize)
{ … }


/* 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)
{ … }

/* note : this variant can't fail */
size_t ZSTD_initDStream(ZSTD_DStream* zds)
{ … }

/* 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)
{ … }

/* ZSTD_resetDStream() :
 * return : expected size, aka ZSTD_startingInputLength().
 * this function cannot fail */
size_t ZSTD_resetDStream(ZSTD_DStream* dctx)
{ … }


size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
{ … }

/* 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)
{ … }

size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format)
{ … }

ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam)
{ … }

/* ZSTD_dParam_withinBounds:
 * @return 1 if value is within dParam bounds,
 * 0 otherwise */
static int ZSTD_dParam_withinBounds(ZSTD_dParameter dParam, int value)
{ … }

#define CHECK_DBOUNDS(p,v) …

size_t ZSTD_DCtx_getParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int* value)
{ … }

size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter dParam, int value)
{ … }

size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset)
{ … }


size_t ZSTD_sizeof_DStream(const ZSTD_DStream* dctx)
{ … }

static size_t ZSTD_decodingBufferSize_internal(unsigned long long windowSize, unsigned long long frameContentSize, size_t blockSizeMax)
{ … }

size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long long frameContentSize)
{ … }

size_t ZSTD_estimateDStreamSize(size_t windowSize)
{ … }

size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize)
{ … }


/* *****   Decompression   ***** */

static int ZSTD_DCtx_isOverflow(ZSTD_DStream* zds, size_t const neededInBuffSize, size_t const neededOutBuffSize)
{ … }

static void ZSTD_DCtx_updateOversizedDuration(ZSTD_DStream* zds, size_t const neededInBuffSize, size_t const neededOutBuffSize)
{ … }

static int ZSTD_DCtx_isOversizedTooLong(ZSTD_DStream* zds)
{ … }

/* 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)
{ … }

/* 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) { … }

size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
{ … }

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)
{ … }