FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/zstd/lib/common/huf.h

     /* ******************************************************************
      * huff0 huffman codec,
      * part of Finite State Entropy library
      * Copyright (c) 2013-2020, Yann Collet, Facebook, Inc.
      *
      * You can contact the author at :
      * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
      *
      * 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 HUF_H_298734234
    #define HUF_H_298734234
    
    /* *** Dependencies *** */
    #include <stddef.h>    /* size_t */
    
    
    /* *** library symbols visibility *** */
    /* Note : when linking with -fvisibility=hidden on gcc, or by default on Visual,
     *        HUF symbols remain "private" (internal symbols for library only).
     *        Set macro FSE_DLL_EXPORT to 1 if you want HUF symbols visible on DLL interface */
    #if defined(FSE_DLL_EXPORT) && (FSE_DLL_EXPORT==1) && defined(__GNUC__) && (__GNUC__ >= 4)
    #  define HUF_PUBLIC_API __attribute__ ((visibility ("default")))
    #elif defined(FSE_DLL_EXPORT) && (FSE_DLL_EXPORT==1)   /* Visual expected */
    #  define HUF_PUBLIC_API __declspec(dllexport)
    #elif defined(FSE_DLL_IMPORT) && (FSE_DLL_IMPORT==1)
    #  define HUF_PUBLIC_API __declspec(dllimport)  /* not required, just to generate faster code (saves a function pointer load from IAT and an indirect jump) */
    #else
    #  define HUF_PUBLIC_API
    #endif
    
    
    /* ========================== */
    /* ***  simple functions  *** */
    /* ========================== */
    
    /** HUF_compress() :
     *  Compress content from buffer 'src', of size 'srcSize', into buffer 'dst'.
     * 'dst' buffer must be already allocated.
     *  Compression runs faster if `dstCapacity` >= HUF_compressBound(srcSize).
     * `srcSize` must be <= `HUF_BLOCKSIZE_MAX` == 128 KB.
     * @return : size of compressed data (<= `dstCapacity`).
     *  Special values : if return == 0, srcData is not compressible => Nothing is stored within dst !!!
     *                   if HUF_isError(return), compression failed (more details using HUF_getErrorName())
     */
    HUF_PUBLIC_API size_t HUF_compress(void* dst, size_t dstCapacity,
                                 const void* src, size_t srcSize);
    
    /** HUF_decompress() :
     *  Decompress HUF data from buffer 'cSrc', of size 'cSrcSize',
     *  into already allocated buffer 'dst', of minimum size 'dstSize'.
     * `originalSize` : **must** be the ***exact*** size of original (uncompressed) data.
     *  Note : in contrast with FSE, HUF_decompress can regenerate
     *         RLE (cSrcSize==1) and uncompressed (cSrcSize==dstSize) data,
     *         because it knows size to regenerate (originalSize).
     * @return : size of regenerated data (== originalSize),
     *           or an error code, which can be tested using HUF_isError()
     */
    HUF_PUBLIC_API size_t HUF_decompress(void* dst,  size_t originalSize,
                                   const void* cSrc, size_t cSrcSize);
    
    
    /* ***   Tool functions *** */
    #define HUF_BLOCKSIZE_MAX (128 * 1024)                  /**< maximum input size for a single block compressed with HUF_compress */
    HUF_PUBLIC_API size_t HUF_compressBound(size_t size);   /**< maximum compressed size (worst case) */
    
    /* Error Management */
    HUF_PUBLIC_API unsigned    HUF_isError(size_t code);       /**< tells if a return value is an error code */
    HUF_PUBLIC_API const char* HUF_getErrorName(size_t code);  /**< provides error code string (useful for debugging) */
    
    
    /* ***   Advanced function   *** */
    
    /** HUF_compress2() :
     *  Same as HUF_compress(), but offers control over `maxSymbolValue` and `tableLog`.
     * `maxSymbolValue` must be <= HUF_SYMBOLVALUE_MAX .
     * `tableLog` must be `<= HUF_TABLELOG_MAX` . */
    HUF_PUBLIC_API size_t HUF_compress2 (void* dst, size_t dstCapacity,
                                   const void* src, size_t srcSize,
                                   unsigned maxSymbolValue, unsigned tableLog);
    
    /** HUF_compress4X_wksp() :
     *  Same as HUF_compress2(), but uses externally allocated `workSpace`.
     * `workspace` must have minimum alignment of 4, and be at least as large as HUF_WORKSPACE_SIZE */
    #define HUF_WORKSPACE_SIZE ((6 << 10) + 256)
    #define HUF_WORKSPACE_SIZE_U32 (HUF_WORKSPACE_SIZE / sizeof(U32))
    HUF_PUBLIC_API size_t HUF_compress4X_wksp (void* dst, size_t dstCapacity,
                                         const void* src, size_t srcSize,
                                         unsigned maxSymbolValue, unsigned tableLog,
                                         void* workSpace, size_t wkspSize);
    
   #endif   /* HUF_H_298734234 */
   
   /* ******************************************************************
    *  WARNING !!
    *  The following section contains advanced and experimental definitions
    *  which shall never be used in the context of a dynamic library,
    *  because they are not guaranteed to remain stable in the future.
    *  Only consider them in association with static linking.
    * *****************************************************************/
   #if defined(HUF_STATIC_LINKING_ONLY) && !defined(HUF_H_HUF_STATIC_LINKING_ONLY)
   #define HUF_H_HUF_STATIC_LINKING_ONLY
   
   /* *** Dependencies *** */
   #include "mem.h"   /* U32 */
   
   
   /* *** Constants *** */
   #define HUF_TABLELOG_MAX      12      /* max runtime value of tableLog (due to static allocation); can be modified up to HUF_ABSOLUTEMAX_TABLELOG */
   #define HUF_TABLELOG_DEFAULT  11      /* default tableLog value when none specified */
   #define HUF_SYMBOLVALUE_MAX  255
   
   #define HUF_TABLELOG_ABSOLUTEMAX  15  /* absolute limit of HUF_MAX_TABLELOG. Beyond that value, code does not work */
   #if (HUF_TABLELOG_MAX > HUF_TABLELOG_ABSOLUTEMAX)
   #  error "HUF_TABLELOG_MAX is too large !"
   #endif
   
   
   /* ****************************************
   *  Static allocation
   ******************************************/
   /* HUF buffer bounds */
   #define HUF_CTABLEBOUND 129
   #define HUF_BLOCKBOUND(size) (size + (size>>8) + 8)   /* only true when incompressible is pre-filtered with fast heuristic */
   #define HUF_COMPRESSBOUND(size) (HUF_CTABLEBOUND + HUF_BLOCKBOUND(size))   /* Macro version, useful for static allocation */
   
   /* static allocation of HUF's Compression Table */
   #define HUF_CTABLE_SIZE_U32(maxSymbolValue)   ((maxSymbolValue)+1)   /* Use tables of U32, for proper alignment */
   #define HUF_CTABLE_SIZE(maxSymbolValue)       (HUF_CTABLE_SIZE_U32(maxSymbolValue) * sizeof(U32))
   #define HUF_CREATE_STATIC_CTABLE(name, maxSymbolValue) \
       U32 name##hb[HUF_CTABLE_SIZE_U32(maxSymbolValue)]; \
       void* name##hv = &(name##hb); \
       HUF_CElt* name = (HUF_CElt*)(name##hv)   /* no final ; */
   
   /* static allocation of HUF's DTable */
   typedef U32 HUF_DTable;
   #define HUF_DTABLE_SIZE(maxTableLog)   (1 + (1<<(maxTableLog)))
   #define HUF_CREATE_STATIC_DTABLEX1(DTable, maxTableLog) \
           HUF_DTable DTable[HUF_DTABLE_SIZE((maxTableLog)-1)] = { ((U32)((maxTableLog)-1) * 0x01000001) }
   #define HUF_CREATE_STATIC_DTABLEX2(DTable, maxTableLog) \
           HUF_DTable DTable[HUF_DTABLE_SIZE(maxTableLog)] = { ((U32)(maxTableLog) * 0x01000001) }
   
   
   /* ****************************************
   *  Advanced decompression functions
   ******************************************/
   size_t HUF_decompress4X1 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);   /**< single-symbol decoder */
   #ifndef HUF_FORCE_DECOMPRESS_X1
   size_t HUF_decompress4X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);   /**< double-symbols decoder */
   #endif
   
   size_t HUF_decompress4X_DCtx (HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);   /**< decodes RLE and uncompressed */
   size_t HUF_decompress4X_hufOnly(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize); /**< considers RLE and uncompressed as errors */
   size_t HUF_decompress4X_hufOnly_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize); /**< considers RLE and uncompressed as errors */
   size_t HUF_decompress4X1_DCtx(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);   /**< single-symbol decoder */
   size_t HUF_decompress4X1_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize);   /**< single-symbol decoder */
   #ifndef HUF_FORCE_DECOMPRESS_X1
   size_t HUF_decompress4X2_DCtx(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);   /**< double-symbols decoder */
   size_t HUF_decompress4X2_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize);   /**< double-symbols decoder */
   #endif
   
   
   /* ****************************************
    *  HUF detailed API
    * ****************************************/
   
   /*! HUF_compress() does the following:
    *  1. count symbol occurrence from source[] into table count[] using FSE_count() (exposed within "fse.h")
    *  2. (optional) refine tableLog using HUF_optimalTableLog()
    *  3. build Huffman table from count using HUF_buildCTable()
    *  4. save Huffman table to memory buffer using HUF_writeCTable()
    *  5. encode the data stream using HUF_compress4X_usingCTable()
    *
    *  The following API allows targeting specific sub-functions for advanced tasks.
    *  For example, it's possible to compress several blocks using the same 'CTable',
    *  or to save and regenerate 'CTable' using external methods.
    */
   unsigned HUF_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue);
   typedef struct HUF_CElt_s HUF_CElt;   /* incomplete type */
   size_t HUF_buildCTable (HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue, unsigned maxNbBits);   /* @return : maxNbBits; CTable and count can overlap. In which case, CTable will overwrite count content */
   size_t HUF_writeCTable (void* dst, size_t maxDstSize, const HUF_CElt* CTable, unsigned maxSymbolValue, unsigned huffLog);
   size_t HUF_compress4X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable);
   size_t HUF_estimateCompressedSize(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue);
   int HUF_validateCTable(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue);
   
   typedef enum {
      HUF_repeat_none,  /**< Cannot use the previous table */
      HUF_repeat_check, /**< Can use the previous table but it must be checked. Note : The previous table must have been constructed by HUF_compress{1, 4}X_repeat */
      HUF_repeat_valid  /**< Can use the previous table and it is assumed to be valid */
    } HUF_repeat;
   /** HUF_compress4X_repeat() :
    *  Same as HUF_compress4X_wksp(), but considers using hufTable if *repeat != HUF_repeat_none.
    *  If it uses hufTable it does not modify hufTable or repeat.
    *  If it doesn't, it sets *repeat = HUF_repeat_none, and it sets hufTable to the table used.
    *  If preferRepeat then the old table will always be used if valid. */
   size_t HUF_compress4X_repeat(void* dst, size_t dstSize,
                          const void* src, size_t srcSize,
                          unsigned maxSymbolValue, unsigned tableLog,
                          void* workSpace, size_t wkspSize,    /**< `workSpace` must be aligned on 4-bytes boundaries, `wkspSize` must be >= HUF_WORKSPACE_SIZE */
                          HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, int bmi2);
   
   /** HUF_buildCTable_wksp() :
    *  Same as HUF_buildCTable(), but using externally allocated scratch buffer.
    * `workSpace` must be aligned on 4-bytes boundaries, and its size must be >= HUF_CTABLE_WORKSPACE_SIZE.
    */
   #define HUF_CTABLE_WORKSPACE_SIZE_U32 (2*HUF_SYMBOLVALUE_MAX +1 +1)
   #define HUF_CTABLE_WORKSPACE_SIZE (HUF_CTABLE_WORKSPACE_SIZE_U32 * sizeof(unsigned))
   size_t HUF_buildCTable_wksp (HUF_CElt* tree,
                          const unsigned* count, U32 maxSymbolValue, U32 maxNbBits,
                                void* workSpace, size_t wkspSize);
   
   /*! HUF_readStats() :
    *  Read compact Huffman tree, saved by HUF_writeCTable().
    * `huffWeight` is destination buffer.
    * @return : size read from `src` , or an error Code .
    *  Note : Needed by HUF_readCTable() and HUF_readDTableXn() . */
   size_t HUF_readStats(BYTE* huffWeight, size_t hwSize,
                        U32* rankStats, U32* nbSymbolsPtr, U32* tableLogPtr,
                        const void* src, size_t srcSize);
   
   /** HUF_readCTable() :
    *  Loading a CTable saved with HUF_writeCTable() */
   size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize, unsigned *hasZeroWeights);
   
   /** HUF_getNbBits() :
    *  Read nbBits from CTable symbolTable, for symbol `symbolValue` presumed <= HUF_SYMBOLVALUE_MAX
    *  Note 1 : is not inlined, as HUF_CElt definition is private
    *  Note 2 : const void* used, so that it can provide a statically allocated table as argument (which uses type U32) */
   U32 HUF_getNbBits(const void* symbolTable, U32 symbolValue);
   
   /*
    * HUF_decompress() does the following:
    * 1. select the decompression algorithm (X1, X2) based on pre-computed heuristics
    * 2. build Huffman table from save, using HUF_readDTableX?()
    * 3. decode 1 or 4 segments in parallel using HUF_decompress?X?_usingDTable()
    */
   
   /** HUF_selectDecoder() :
    *  Tells which decoder is likely to decode faster,
    *  based on a set of pre-computed metrics.
    * @return : 0==HUF_decompress4X1, 1==HUF_decompress4X2 .
    *  Assumption : 0 < dstSize <= 128 KB */
   U32 HUF_selectDecoder (size_t dstSize, size_t cSrcSize);
   
   /**
    *  The minimum workspace size for the `workSpace` used in
    *  HUF_readDTableX1_wksp() and HUF_readDTableX2_wksp().
    *
    *  The space used depends on HUF_TABLELOG_MAX, ranging from ~1500 bytes when
    *  HUF_TABLE_LOG_MAX=12 to ~1850 bytes when HUF_TABLE_LOG_MAX=15.
    *  Buffer overflow errors may potentially occur if code modifications result in
    *  a required workspace size greater than that specified in the following
    *  macro.
    */
   #define HUF_DECOMPRESS_WORKSPACE_SIZE (2 << 10)
   #define HUF_DECOMPRESS_WORKSPACE_SIZE_U32 (HUF_DECOMPRESS_WORKSPACE_SIZE / sizeof(U32))
   
   #ifndef HUF_FORCE_DECOMPRESS_X2
   size_t HUF_readDTableX1 (HUF_DTable* DTable, const void* src, size_t srcSize);
   size_t HUF_readDTableX1_wksp (HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize);
   #endif
   #ifndef HUF_FORCE_DECOMPRESS_X1
   size_t HUF_readDTableX2 (HUF_DTable* DTable, const void* src, size_t srcSize);
   size_t HUF_readDTableX2_wksp (HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize);
   #endif
   
   size_t HUF_decompress4X_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable);
   #ifndef HUF_FORCE_DECOMPRESS_X2
   size_t HUF_decompress4X1_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable);
   #endif
   #ifndef HUF_FORCE_DECOMPRESS_X1
   size_t HUF_decompress4X2_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable);
   #endif
   
   
   /* ====================== */
   /* single stream variants */
   /* ====================== */
   
   size_t HUF_compress1X (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned tableLog);
   size_t HUF_compress1X_wksp (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned tableLog, void* workSpace, size_t wkspSize);  /**< `workSpace` must be a table of at least HUF_WORKSPACE_SIZE_U32 unsigned */
   size_t HUF_compress1X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable);
   /** HUF_compress1X_repeat() :
    *  Same as HUF_compress1X_wksp(), but considers using hufTable if *repeat != HUF_repeat_none.
    *  If it uses hufTable it does not modify hufTable or repeat.
    *  If it doesn't, it sets *repeat = HUF_repeat_none, and it sets hufTable to the table used.
    *  If preferRepeat then the old table will always be used if valid. */
   size_t HUF_compress1X_repeat(void* dst, size_t dstSize,
                          const void* src, size_t srcSize,
                          unsigned maxSymbolValue, unsigned tableLog,
                          void* workSpace, size_t wkspSize,   /**< `workSpace` must be aligned on 4-bytes boundaries, `wkspSize` must be >= HUF_WORKSPACE_SIZE */
                          HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, int bmi2);
   
   size_t HUF_decompress1X1 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);   /* single-symbol decoder */
   #ifndef HUF_FORCE_DECOMPRESS_X1
   size_t HUF_decompress1X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);   /* double-symbol decoder */
   #endif
   
   size_t HUF_decompress1X_DCtx (HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);
   size_t HUF_decompress1X_DCtx_wksp (HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize);
   #ifndef HUF_FORCE_DECOMPRESS_X2
   size_t HUF_decompress1X1_DCtx(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);   /**< single-symbol decoder */
   size_t HUF_decompress1X1_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize);   /**< single-symbol decoder */
   #endif
   #ifndef HUF_FORCE_DECOMPRESS_X1
   size_t HUF_decompress1X2_DCtx(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);   /**< double-symbols decoder */
   size_t HUF_decompress1X2_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize);   /**< double-symbols decoder */
   #endif
   
   size_t HUF_decompress1X_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable);   /**< automatic selection of sing or double symbol decoder, based on DTable */
   #ifndef HUF_FORCE_DECOMPRESS_X2
   size_t HUF_decompress1X1_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable);
   #endif
   #ifndef HUF_FORCE_DECOMPRESS_X1
   size_t HUF_decompress1X2_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable);
   #endif
   
   /* BMI2 variants.
    * If the CPU has BMI2 support, pass bmi2=1, otherwise pass bmi2=0.
    */
   size_t HUF_decompress1X_usingDTable_bmi2(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int bmi2);
   #ifndef HUF_FORCE_DECOMPRESS_X2
   size_t HUF_decompress1X1_DCtx_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int bmi2);
   #endif
   size_t HUF_decompress4X_usingDTable_bmi2(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int bmi2);
   size_t HUF_decompress4X_hufOnly_wksp_bmi2(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int bmi2);
   
   #endif /* HUF_STATIC_LINKING_ONLY */
   
   #if defined (__cplusplus)
   }
   #endif

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