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      1 /*
      2  * Copyright (c) Yann Collet, Meta Platforms, Inc. and affiliates.
      3  * All rights reserved.
      4  *
      5  * This source code is licensed under both the BSD-style license (found in the
      6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
      7  * in the COPYING file in the root directory of this source tree).
      8  * You may select, at your option, one of the above-listed licenses.
      9  */
     10 
     11 #ifndef ZSTDv06_H
     12 #define ZSTDv06_H
     13 
     14 #if defined (__cplusplus)
     15 extern "C" {
     16 #endif
     17 
     18 /*======  Dependency  ======*/
     19 #include <stddef.h>   /* size_t */
     20 
     21 
     22 /*======  Export for Windows  ======*/
     23 /*!
     24 *  ZSTDv06_DLL_EXPORT :
     25 *  Enable exporting of functions when building a Windows DLL
     26 */
     27 #if defined(_WIN32) && defined(ZSTDv06_DLL_EXPORT) && (ZSTDv06_DLL_EXPORT==1)
     28 #  define ZSTDLIBv06_API __declspec(dllexport)
     29 #else
     30 #  define ZSTDLIBv06_API
     31 #endif
     32 
     33 
     34 /* *************************************
     35 *  Simple functions
     36 ***************************************/
     37 /*! ZSTDv06_decompress() :
     38     `compressedSize` : is the _exact_ size of the compressed blob, otherwise decompression will fail.
     39     `dstCapacity` must be large enough, equal or larger than originalSize.
     40     @return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
     41               or an errorCode if it fails (which can be tested using ZSTDv06_isError()) */
     42 ZSTDLIBv06_API size_t ZSTDv06_decompress( void* dst, size_t dstCapacity,
     43                                     const void* src, size_t compressedSize);
     44 
     45 /**
     46 ZSTDv06_findFrameSizeInfoLegacy() : get the source length and decompressed bound of a ZSTD frame compliant with v0.6.x format
     47     srcSize : The size of the 'src' buffer, at least as large as the frame pointed to by 'src'
     48     cSize (output parameter)  : the number of bytes that would be read to decompress this frame
     49                                 or an error code if it fails (which can be tested using ZSTDv01_isError())
     50     dBound (output parameter) : an upper-bound for the decompressed size of the data in the frame
     51                                 or ZSTD_CONTENTSIZE_ERROR if an error occurs
     52 
     53     note : assumes `cSize` and `dBound` are _not_ NULL.
     54 */
     55 void ZSTDv06_findFrameSizeInfoLegacy(const void *src, size_t srcSize,
     56                                      size_t* cSize, unsigned long long* dBound);
     57 
     58 /* *************************************
     59 *  Helper functions
     60 ***************************************/
     61 ZSTDLIBv06_API size_t      ZSTDv06_compressBound(size_t srcSize); /*!< maximum compressed size (worst case scenario) */
     62 
     63 /* Error Management */
     64 ZSTDLIBv06_API unsigned    ZSTDv06_isError(size_t code);          /*!< tells if a `size_t` function result is an error code */
     65 ZSTDLIBv06_API const char* ZSTDv06_getErrorName(size_t code);     /*!< provides readable string for an error code */
     66 
     67 
     68 /* *************************************
     69 *  Explicit memory management
     70 ***************************************/
     71 /** Decompression context */
     72 typedef struct ZSTDv06_DCtx_s ZSTDv06_DCtx;
     73 ZSTDLIBv06_API ZSTDv06_DCtx* ZSTDv06_createDCtx(void);
     74 ZSTDLIBv06_API size_t     ZSTDv06_freeDCtx(ZSTDv06_DCtx* dctx);      /*!< @return : errorCode */
     75 
     76 /** ZSTDv06_decompressDCtx() :
     77 *   Same as ZSTDv06_decompress(), but requires an already allocated ZSTDv06_DCtx (see ZSTDv06_createDCtx()) */
     78 ZSTDLIBv06_API size_t ZSTDv06_decompressDCtx(ZSTDv06_DCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
     79 
     80 
     81 /*-***********************
     82 *  Dictionary API
     83 *************************/
     84 /*! ZSTDv06_decompress_usingDict() :
     85 *   Decompression using a pre-defined Dictionary content (see dictBuilder).
     86 *   Dictionary must be identical to the one used during compression, otherwise regenerated data will be corrupted.
     87 *   Note : dict can be NULL, in which case, it's equivalent to ZSTDv06_decompressDCtx() */
     88 ZSTDLIBv06_API size_t ZSTDv06_decompress_usingDict(ZSTDv06_DCtx* dctx,
     89                                                    void* dst, size_t dstCapacity,
     90                                              const void* src, size_t srcSize,
     91                                              const void* dict,size_t dictSize);
     92 
     93 
     94 /*-************************
     95 *  Advanced Streaming API
     96 ***************************/
     97 struct ZSTDv06_frameParams_s { unsigned long long frameContentSize; unsigned windowLog; };
     98 typedef struct ZSTDv06_frameParams_s ZSTDv06_frameParams;
     99 
    100 ZSTDLIBv06_API size_t ZSTDv06_getFrameParams(ZSTDv06_frameParams* fparamsPtr, const void* src, size_t srcSize);   /**< doesn't consume input */
    101 ZSTDLIBv06_API size_t ZSTDv06_decompressBegin_usingDict(ZSTDv06_DCtx* dctx, const void* dict, size_t dictSize);
    102 ZSTDLIBv06_API void   ZSTDv06_copyDCtx(ZSTDv06_DCtx* dctx, const ZSTDv06_DCtx* preparedDCtx);
    103 
    104 ZSTDLIBv06_API size_t ZSTDv06_nextSrcSizeToDecompress(ZSTDv06_DCtx* dctx);
    105 ZSTDLIBv06_API size_t ZSTDv06_decompressContinue(ZSTDv06_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
    106 
    107 
    108 
    109 /* *************************************
    110 *  ZBUFF API
    111 ***************************************/
    112 
    113 typedef struct ZBUFFv06_DCtx_s ZBUFFv06_DCtx;
    114 ZSTDLIBv06_API ZBUFFv06_DCtx* ZBUFFv06_createDCtx(void);
    115 ZSTDLIBv06_API size_t         ZBUFFv06_freeDCtx(ZBUFFv06_DCtx* dctx);
    116 
    117 ZSTDLIBv06_API size_t ZBUFFv06_decompressInit(ZBUFFv06_DCtx* dctx);
    118 ZSTDLIBv06_API size_t ZBUFFv06_decompressInitDictionary(ZBUFFv06_DCtx* dctx, const void* dict, size_t dictSize);
    119 
    120 ZSTDLIBv06_API size_t ZBUFFv06_decompressContinue(ZBUFFv06_DCtx* dctx,
    121                                                   void* dst, size_t* dstCapacityPtr,
    122                                             const void* src, size_t* srcSizePtr);
    123 
    124 /*-***************************************************************************
    125 *  Streaming decompression howto
    126 *
    127 *  A ZBUFFv06_DCtx object is required to track streaming operations.
    128 *  Use ZBUFFv06_createDCtx() and ZBUFFv06_freeDCtx() to create/release resources.
    129 *  Use ZBUFFv06_decompressInit() to start a new decompression operation,
    130 *   or ZBUFFv06_decompressInitDictionary() if decompression requires a dictionary.
    131 *  Note that ZBUFFv06_DCtx objects can be re-init multiple times.
    132 *
    133 *  Use ZBUFFv06_decompressContinue() repetitively to consume your input.
    134 *  *srcSizePtr and *dstCapacityPtr can be any size.
    135 *  The function will report how many bytes were read or written by modifying *srcSizePtr and *dstCapacityPtr.
    136 *  Note that it may not consume the entire input, in which case it's up to the caller to present remaining input again.
    137 *  The content of `dst` will be overwritten (up to *dstCapacityPtr) at each function call, so save its content if it matters, or change `dst`.
    138 *  @return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to help latency),
    139 *            or 0 when a frame is completely decoded,
    140 *            or an error code, which can be tested using ZBUFFv06_isError().
    141 *
    142 *  Hint : recommended buffer sizes (not compulsory) : ZBUFFv06_recommendedDInSize() and ZBUFFv06_recommendedDOutSize()
    143 *  output : ZBUFFv06_recommendedDOutSize== 128 KB block size is the internal unit, it ensures it's always possible to write a full block when decoded.
    144 *  input  : ZBUFFv06_recommendedDInSize == 128KB + 3;
    145 *           just follow indications from ZBUFFv06_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
    146 * *******************************************************************************/
    147 
    148 
    149 /* *************************************
    150 *  Tool functions
    151 ***************************************/
    152 ZSTDLIBv06_API unsigned ZBUFFv06_isError(size_t errorCode);
    153 ZSTDLIBv06_API const char* ZBUFFv06_getErrorName(size_t errorCode);
    154 
    155 /** Functions below provide recommended buffer sizes for Compression or Decompression operations.
    156 *   These sizes are just hints, they tend to offer better latency */
    157 ZSTDLIBv06_API size_t ZBUFFv06_recommendedDInSize(void);
    158 ZSTDLIBv06_API size_t ZBUFFv06_recommendedDOutSize(void);
    159 
    160 
    161 /*-*************************************
    162 *  Constants
    163 ***************************************/
    164 #define ZSTDv06_MAGICNUMBER 0xFD2FB526   /* v0.6 */
    165 
    166 
    167 
    168 #if defined (__cplusplus)
    169 }
    170 #endif
    171 
    172 #endif  /* ZSTDv06_BUFFERED_H */
    173