/*

 * Copyright (c) 2016-present, 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.

 */

#if defined (__cplusplus)

extern "C" {

#endif

#ifndef ZSTD_H_235446

#define ZSTD_H_235446

/* ======   Dependency   ======*/

#include <stddef.h>   /* size_t */

/* =====   ZSTDLIB_API : control library symbols visibility   ===== */

#ifndef ZSTDLIB_VISIBILITY

#  if defined(__GNUC__) && (__GNUC__ >= 4)

#    define ZSTDLIB_VISIBILITY __attribute__ ((visibility ("default")))

#  else

#    define ZSTDLIB_VISIBILITY

#  endif

#endif

#if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)

#  define ZSTDLIB_API __declspec(dllexport) ZSTDLIB_VISIBILITY

#elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1)

#  define ZSTDLIB_API __declspec(dllimport) ZSTDLIB_VISIBILITY /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/

#else

#  define ZSTDLIB_API ZSTDLIB_VISIBILITY

#endif

/*******************************************************************************************************

  Introduction

  zstd, short for Zstandard, is a fast lossless compression algorithm,

  targeting real-time compression scenarios at zlib-level and better compression ratios.

  The zstd compression library provides in-memory compression and decompression functions.

  The library supports compression levels from 1 up to ZSTD_maxCLevel() which is currently 22.

  Levels >= 20, labeled `--ultra`, should be used with caution, as they require more memory.

  Compression can be done in:

    - a single step (described as Simple API)

    - a single step, reusing a context (described as Explicit context)

    - unbounded multiple steps (described as Streaming compression)

  The compression ratio achievable on small data can be highly improved using a dictionary in:

    - a single step (described as Simple dictionary API)

    - a single step, reusing a dictionary (described as Bulk-processing dictionary API)

  Advanced experimental functions can be accessed using #define ZSTD_STATIC_LINKING_ONLY before including zstd.h.

  Advanced experimental APIs shall never be used with a dynamic library.

  They are not "stable", their definition may change in the future. Only static linking is allowed.

*********************************************************************************************************/

/*------   Version   ------*/

#define ZSTD_VERSION_MAJOR    1

#define ZSTD_VERSION_MINOR    3

#define ZSTD_VERSION_RELEASE  4

#define ZSTD_VERSION_NUMBER  (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE)

ZSTDLIB_API unsigned ZSTD_versionNumber(void);   /**< useful to check dll version */

#define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE

#define ZSTD_QUOTE(str) #str

#define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str)

#define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION)

ZSTDLIB_API const char* ZSTD_versionString(void);   /* added in v1.3.0 */

/***************************************

*  Simple API

***************************************/

/*! ZSTD_compress() :

 *  Compresses `src` content as a single zstd compressed frame into already allocated `dst`.

 *  Hint : compression runs faster if `dstCapacity` >=  `ZSTD_compressBound(srcSize)`.

 *  @return : compressed size written into `dst` (<= `dstCapacity),

 *            or an error code if it fails (which can be tested using ZSTD_isError()). */

ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity,

                            const void* src, size_t srcSize,

                                  int compressionLevel);

/*! ZSTD_decompress() :

 *  `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames.

 *  `dstCapacity` is an upper bound of originalSize to regenerate.

 *  If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data.

 *  @return : the number of bytes decompressed into `dst` (<= `dstCapacity`),

 *            or an errorCode if it fails (which can be tested using ZSTD_isError()). */

ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity,

                              const void* src, size_t compressedSize);

/*! ZSTD_getFrameContentSize() : added in v1.3.0

 *  `src` should point to the start of a ZSTD encoded frame.

 *  `srcSize` must be at least as large as the frame header.

 *            hint : any size >= `ZSTD_frameHeaderSize_max` is large enough.

 *  @return : - decompressed size of the frame in `src`, if known

 *            - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined

 *            - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small)

 *   note 1 : a 0 return value means the frame is valid but "empty".

 *   note 2 : decompressed size is an optional field, it may not be present, typically in streaming mode.

 *            When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size.

 *            In which case, it's necessary to use streaming mode to decompress data.

 *            Optionally, application can rely on some implicit limit,

 *            as ZSTD_decompress() only needs an upper bound of decompressed size.

 *            (For example, data could be necessarily cut into blocks <= 16 KB).

 *   note 3 : decompressed size is always present when compression is done with ZSTD_compress()

 *   note 4 : decompressed size can be very large (64-bits value),

 *            potentially larger than what local system can handle as a single memory segment.

 *            In which case, it's necessary to use streaming mode to decompress data.

 *   note 5 : If source is untrusted, decompressed size could be wrong or intentionally modified.

 *            Always ensure return value fits within application's authorized limits.

 *            Each application can set its own limits.

 *   note 6 : This function replaces ZSTD_getDecompressedSize() */

#define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1)

#define ZSTD_CONTENTSIZE_ERROR   (0ULL - 2)

ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize);

/*! ZSTD_getDecompressedSize() :

 *  NOTE: This function is now obsolete, in favor of ZSTD_getFrameContentSize().

 *  Both functions work the same way, but ZSTD_getDecompressedSize() blends

 *  "empty", "unknown" and "error" results to the same return value (0),

 *  while ZSTD_getFrameContentSize() gives them separate return values.

 * `src` is the start of a zstd compressed frame.

 * @return : content size to be decompressed, as a 64-bits value _if known and not empty_, 0 otherwise. */

ZSTDLIB_API unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize);

/*======  Helper functions  ======*/

#define ZSTD_COMPRESSBOUND(srcSize)   ((srcSize) + ((srcSize)>>8) + (((srcSize) < (128<<10)) ? (((128<<10) - (srcSize)) >> 11) /* margin, from 64 to 0 */ : 0))  /* this formula ensures that bound(A) + bound(B) <= bound(A+B) as long as A and B >= 128 KB */

ZSTDLIB_API size_t      ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case single-pass scenario */

ZSTDLIB_API unsigned    ZSTD_isError(size_t code);          /*!< tells if a `size_t` function result is an error code */

ZSTDLIB_API const char* ZSTD_getErrorName(size_t code);     /*!< provides readable string from an error code */

ZSTDLIB_API int         ZSTD_maxCLevel(void);               /*!< maximum compression level available */

/***************************************

*  Explicit context

***************************************/

/*= Compression context

 *  When compressing many times,

 *  it is recommended to allocate a context just once, and re-use it for each successive compression operation.

 *  This will make workload friendlier for system's memory.

 *  Use one context per thread for parallel execution in multi-threaded environments. */

typedef struct ZSTD_CCtx_s ZSTD_CCtx;

ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void);

ZSTDLIB_API size_t     ZSTD_freeCCtx(ZSTD_CCtx* cctx);

/*! ZSTD_compressCCtx() :

 *  Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx()). */

ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx,

                                     void* dst, size_t dstCapacity,

                               const void* src, size_t srcSize,

                                     int compressionLevel);

/*= Decompression context

 *  When decompressing many times,

 *  it is recommended to allocate a context only once,

 *  and re-use it for each successive compression operation.

 *  This will make workload friendlier for system's memory.

 *  Use one context per thread for parallel execution. */

typedef struct ZSTD_DCtx_s ZSTD_DCtx;

ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void);

ZSTDLIB_API size_t     ZSTD_freeDCtx(ZSTD_DCtx* dctx);

/*! ZSTD_decompressDCtx() :

 *  Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()) */

ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx,

                                       void* dst, size_t dstCapacity,

                                 const void* src, size_t srcSize);

/**************************

*  Simple dictionary API

***************************/

/*! ZSTD_compress_usingDict() :

 *  Compression using a predefined Dictionary (see dictBuilder/zdict.h).

 *  Note : This function loads the dictionary, resulting in significant startup delay.

 *  Note : When `dict == NULL || dictSize < 8` no dictionary is used. */

ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx,

                                           void* dst, size_t dstCapacity,

                                     const void* src, size_t srcSize,

                                     const void* dict,size_t dictSize,

                                           int compressionLevel);

/*! ZSTD_decompress_usingDict() :

 *  Decompression using a predefined Dictionary (see dictBuilder/zdict.h).

 *  Dictionary must be identical to the one used during compression.

 *  Note : This function loads the dictionary, resulting in significant startup delay.

 *  Note : When `dict == NULL || dictSize < 8` no dictionary is used. */

ZSTDLIB_API 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);

/**********************************

 *  Bulk processing dictionary API

 *********************************/

typedef struct ZSTD_CDict_s ZSTD_CDict;

/*! ZSTD_createCDict() :

 *  When compressing multiple messages / blocks with the same dictionary, it's recommended to load it just once.

 *  ZSTD_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay.

 *  ZSTD_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only.

 *  `dictBuffer` can be released after ZSTD_CDict creation, since its content is copied within CDict */

ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize,

                                         int compressionLevel);

/*! ZSTD_freeCDict() :

 *  Function frees memory allocated by ZSTD_createCDict(). */

ZSTDLIB_API size_t      ZSTD_freeCDict(ZSTD_CDict* CDict);

/*! ZSTD_compress_usingCDict() :

 *  Compression using a digested Dictionary.

 *  Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times.

 *  Note that compression level is decided during dictionary creation.

 *  Frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no) */

ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,

                                            void* dst, size_t dstCapacity,

                                      const void* src, size_t srcSize,

                                      const ZSTD_CDict* cdict);

typedef struct ZSTD_DDict_s ZSTD_DDict;

/*! ZSTD_createDDict() :

 *  Create a digested dictionary, ready to start decompression operation without startup delay.

 *  dictBuffer can be released after DDict creation, as its content is copied inside DDict */

ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize);

/*! ZSTD_freeDDict() :

 *  Function frees memory allocated with ZSTD_createDDict() */

ZSTDLIB_API size_t      ZSTD_freeDDict(ZSTD_DDict* ddict);

/*! ZSTD_decompress_usingDDict() :

 *  Decompression using a digested Dictionary.

 *  Faster startup than ZSTD_decompress_usingDict(), recommended when same dictionary is used multiple times. */

ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,

                                              void* dst, size_t dstCapacity,

                                        const void* src, size_t srcSize,

                                        const ZSTD_DDict* ddict);

/****************************

*  Streaming

****************************/

typedef struct ZSTD_inBuffer_s {

  const void* src;    /**< start of input buffer */

  size_t size;        /**< size of input buffer */

  size_t pos;         /**< position where reading stopped. Will be updated. Necessarily 0 <= pos <= size */

} ZSTD_inBuffer;

typedef struct ZSTD_outBuffer_s {

  void*  dst;         /**< start of output buffer */

  size_t size;        /**< size of output buffer */

  size_t pos;         /**< position where writing stopped. Will be updated. Necessarily 0 <= pos <= size */

} ZSTD_outBuffer;

/*-***********************************************************************

*  Streaming compression - HowTo

*

*  A ZSTD_CStream object is required to track streaming operation.

*  Use ZSTD_createCStream() and ZSTD_freeCStream() to create/release resources.

*  ZSTD_CStream objects can be reused multiple times on consecutive compression operations.

*  It is recommended to re-use ZSTD_CStream in situations where many streaming operations will be achieved consecutively,

*  since it will play nicer with system's memory, by re-using already allocated memory.

*  Use one separate ZSTD_CStream per thread for parallel execution.

*

*  Start a new compression by initializing ZSTD_CStream.

*  Use ZSTD_initCStream() to start a new compression operation.

*  Use ZSTD_initCStream_usingDict() or ZSTD_initCStream_usingCDict() for a compression which requires a dictionary (experimental section)

*

*  Use ZSTD_compressStream() repetitively to consume input stream.

*  The function will automatically update both `pos` fields.

*  Note that it may not consume the entire input, in which case `pos < size`,

*  and it's up to the caller to present again remaining data.

*  @return : a size hint, preferred nb of bytes to use as input for next function call

*            or an error code, which can be tested using ZSTD_isError().

*            Note 1 : it's just a hint, to help latency a little, any other value will work fine.

*            Note 2 : size hint is guaranteed to be <= ZSTD_CStreamInSize()

*

*  At any moment, it's possible to flush whatever data remains within internal buffer, using ZSTD_flushStream().

*  `output->pos` will be updated.

*  Note that some content might still be left within internal buffer if `output->size` is too small.

*  @return : nb of bytes still present within internal buffer (0 if it's empty)

*            or an error code, which can be tested using ZSTD_isError().

*

*  ZSTD_endStream() instructs to finish a frame.

*  It will perform a flush and write frame epilogue.

*  The epilogue is required for decoders to consider a frame completed.

*  ZSTD_endStream() may not be able to flush full data if `output->size` is too small.

*  In which case, call again ZSTD_endStream() to complete the flush.

*  @return : 0 if frame fully completed and fully flushed,

             or >0 if some data is still present within internal buffer

                  (value is minimum size estimation for remaining data to flush, but it could be more)

*            or an error code, which can be tested using ZSTD_isError().

*

* *******************************************************************/

typedef ZSTD_CCtx ZSTD_CStream;  /**< CCtx and CStream are now effectively same object (>= v1.3.0) */

                                 /* Continue to distinguish them for compatibility with versions <= v1.2.0 */

/*===== ZSTD_CStream management functions =====*/

ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void);

ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs);

/*===== Streaming compression functions =====*/

ZSTDLIB_API size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel);

ZSTDLIB_API size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input);

ZSTDLIB_API size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output);

ZSTDLIB_API size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output);

ZSTDLIB_API size_t ZSTD_CStreamInSize(void);    /**< recommended size for input buffer */

ZSTDLIB_API size_t ZSTD_CStreamOutSize(void);   /**< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block in all circumstances. */

/*-***************************************************************************

*  Streaming decompression - HowTo

*

*  A ZSTD_DStream object is required to track streaming operations.

*  Use ZSTD_createDStream() and ZSTD_freeDStream() to create/release resources.

*  ZSTD_DStream objects can be re-used multiple times.

*

*  Use ZSTD_initDStream() to start a new decompression operation,

*   or ZSTD_initDStream_usingDict() if decompression requires a dictionary.

*   @return : recommended first input size

*

*  Use ZSTD_decompressStream() repetitively to consume your input.

*  The function will update both `pos` fields.

*  If `input.pos < input.size`, some input has not been consumed.

*  It's up to the caller to present again remaining data.

*  If `output.pos < output.size`, decoder has flushed everything it could.

*  @return : 0 when a frame is completely decoded and fully flushed,

*            an error code, which can be tested using ZSTD_isError(),

*            any other value > 0, which means there is still some decoding to do to complete current frame.

*            The return value is a suggested next input size (a hint to improve latency) that will never load more than the current frame.

* *******************************************************************************/

typedef ZSTD_DCtx ZSTD_DStream;  /**< DCtx and DStream are now effectively same object (>= v1.3.0) */

                                 /* For compatibility with versions <= v1.2.0, continue to consider them separated. */

/*===== ZSTD_DStream management functions =====*/

ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void);

ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds);

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

ZSTDLIB_API size_t ZSTD_initDStream(ZSTD_DStream* zds);

ZSTDLIB_API size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input);

ZSTDLIB_API size_t ZSTD_DStreamInSize(void);    /*!< recommended size for input buffer */

ZSTDLIB_API size_t ZSTD_DStreamOutSize(void);   /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */

#endif  /* ZSTD_H_235446 */

/****************************************************************************************

 * START OF ADVANCED AND EXPERIMENTAL FUNCTIONS

 * The definitions in this section are considered experimental.

 * They should never be used with a dynamic library, as prototypes may change in the future.

 * They are provided for advanced scenarios.

 * Use them only in association with static linking.

 * ***************************************************************************************/

#if defined(ZSTD_STATIC_LINKING_ONLY) && !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY)

#define ZSTD_H_ZSTD_STATIC_LINKING_ONLY

/* --- Constants ---*/

#define ZSTD_MAGICNUMBER            0xFD2FB528   /* >= v0.8.0 */

#define ZSTD_MAGIC_SKIPPABLE_START  0x184D2A50U

#define ZSTD_MAGIC_DICTIONARY       0xEC30A437   /* >= v0.7.0 */

#define ZSTD_WINDOWLOG_MAX_32   30

#define ZSTD_WINDOWLOG_MAX_64   31

#define ZSTD_WINDOWLOG_MAX    ((unsigned)(sizeof(size_t) == 4 ? ZSTD_WINDOWLOG_MAX_32 : ZSTD_WINDOWLOG_MAX_64))

#define ZSTD_WINDOWLOG_MIN      10

#define ZSTD_HASHLOG_MAX      ((ZSTD_WINDOWLOG_MAX < 30) ? ZSTD_WINDOWLOG_MAX : 30)

#define ZSTD_HASHLOG_MIN         6

#define ZSTD_CHAINLOG_MAX_32    29

#define ZSTD_CHAINLOG_MAX_64    30

#define ZSTD_CHAINLOG_MAX     ((unsigned)(sizeof(size_t) == 4 ? ZSTD_CHAINLOG_MAX_32 : ZSTD_CHAINLOG_MAX_64))

#define ZSTD_CHAINLOG_MIN       ZSTD_HASHLOG_MIN

#define ZSTD_HASHLOG3_MAX       17

#define ZSTD_SEARCHLOG_MAX     (ZSTD_WINDOWLOG_MAX-1)

#define ZSTD_SEARCHLOG_MIN       1

#define ZSTD_SEARCHLENGTH_MAX    7   /* only for ZSTD_fast, other strategies are limited to 6 */

#define ZSTD_SEARCHLENGTH_MIN    3   /* only for ZSTD_btopt, other strategies are limited to 4 */

#define ZSTD_TARGETLENGTH_MIN    1   /* only used by btopt, btultra and btfast */

#define ZSTD_LDM_MINMATCH_MIN    4

#define ZSTD_LDM_MINMATCH_MAX 4096

#define ZSTD_LDM_BUCKETSIZELOG_MAX 8

#define ZSTD_FRAMEHEADERSIZE_PREFIX 5   /* minimum input size to know frame header size */

#define ZSTD_FRAMEHEADERSIZE_MIN    6

#define ZSTD_FRAMEHEADERSIZE_MAX   18   /* for static allocation */

static const size_t ZSTD_frameHeaderSize_prefix = ZSTD_FRAMEHEADERSIZE_PREFIX;

static const size_t ZSTD_frameHeaderSize_min = ZSTD_FRAMEHEADERSIZE_MIN;

static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX;

static const size_t ZSTD_skippableHeaderSize = 8;  /* magic number + skippable frame length */

/*--- Advanced types ---*/

typedef enum { ZSTD_fast=1, ZSTD_dfast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2,

               ZSTD_btlazy2, ZSTD_btopt, ZSTD_btultra } ZSTD_strategy;   /* from faster to stronger */

typedef struct {

    unsigned windowLog;      /**< largest match distance : larger == more compression, more memory needed during decompression */

    unsigned chainLog;       /**< fully searched segment : larger == more compression, slower, more memory (useless for fast) */

    unsigned hashLog;        /**< dispatch table : larger == faster, more memory */

    unsigned searchLog;      /**< nb of searches : larger == more compression, slower */

    unsigned searchLength;   /**< match length searched : larger == faster decompression, sometimes less compression */

    unsigned targetLength;   /**< acceptable match size for optimal parser (only) : larger == more compression, slower */

    ZSTD_strategy strategy;

} ZSTD_compressionParameters;

typedef struct {

    unsigned contentSizeFlag; /**< 1: content size will be in frame header (when known) */

    unsigned checksumFlag;    /**< 1: generate a 32-bits checksum at end of frame, for error detection */

    unsigned noDictIDFlag;    /**< 1: no dictID will be saved into frame header (if dictionary compression) */

} ZSTD_frameParameters;

typedef struct {

    ZSTD_compressionParameters cParams;

    ZSTD_frameParameters fParams;

} ZSTD_parameters;

typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params;

typedef enum {

    ZSTD_dct_auto=0,      /* dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */

    ZSTD_dct_rawContent,  /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */

    ZSTD_dct_fullDict     /* refuses to load a dictionary if it does not respect Zstandard's specification */

} ZSTD_dictContentType_e;

typedef enum {

    ZSTD_dlm_byCopy = 0, /**< Copy dictionary content internally */

    ZSTD_dlm_byRef,      /**< Reference dictionary content -- the dictionary buffer must outlive its users. */

} ZSTD_dictLoadMethod_e;

/***************************************

*  Frame size functions

***************************************/

/*! ZSTD_findFrameCompressedSize() :

 *  `src` should point to the start of a ZSTD encoded frame or skippable frame

 *  `srcSize` must be >= first frame size

 *  @return : the compressed size of the first frame starting at `src`,

 *            suitable to pass to `ZSTD_decompress` or similar,

 *            or an error code if input is invalid */

ZSTDLIB_API size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize);

/*! ZSTD_findDecompressedSize() :

 *  `src` should point the start of a series of ZSTD encoded and/or skippable frames

 *  `srcSize` must be the _exact_ size of this series

 *       (i.e. there should be a frame boundary exactly at `srcSize` bytes after `src`)

 *  @return : - decompressed size of all data in all successive frames

 *            - if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN

 *            - if an error occurred: ZSTD_CONTENTSIZE_ERROR

 *

 *   note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode.

 *            When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size.

 *            In which case, it's necessary to use streaming mode to decompress data.

 *   note 2 : decompressed size is always present when compression is done with ZSTD_compress()

 *   note 3 : decompressed size can be very large (64-bits value),

 *            potentially larger than what local system can handle as a single memory segment.

 *            In which case, it's necessary to use streaming mode to decompress data.

 *   note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified.

 *            Always ensure result fits within application's authorized limits.

 *            Each application can set its own limits.

 *   note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to

 *            read each contained frame header.  This is fast as most of the data is skipped,

 *            however it does mean that all frame data must be present and valid. */

ZSTDLIB_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize);

/*! ZSTD_frameHeaderSize() :

*   `src` should point to the start of a ZSTD frame

*   `srcSize` must be >= ZSTD_frameHeaderSize_prefix.

*   @return : size of the Frame Header */

ZSTDLIB_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize);

/***************************************

*  Memory management

***************************************/

/*! ZSTD_sizeof_*() :

 *  These functions give the current memory usage of selected object.

 *  Object memory usage can evolve when re-used. */

ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx);

ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx);

ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs);

ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds);

ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict);

ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);

/*! ZSTD_estimate*() :

 *  These functions make it possible to estimate memory usage