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  Compression can be done in:
    - a single step (described as Simple Functions)
    - a single step, reusing a context (described in Advanced Functions)
    - unbounded multiple steps (described as Streaming compression)

  lz4.h provides block compression functions. It gives full buffer control to user.
  Decompressing an lz4-compressed block also requires metadata (such as compressed size).
  Each application is free to encode such metadata in whichever way it wants.

  An additional format, called LZ4 frame specification (doc/lz4_Frame_format.md),
  take care of encoding standard metadata alongside LZ4-compressed blocks.
  If your application requires interoperability, it's recommended to use it.
  A library is provided to take care of it, see lz4frame.h.
*/

/*^***************************************************************
*  Export parameters
*****************************************************************/
/*
*  LZ4_DLL_EXPORT :
*  Enable exporting of functions when building a Windows DLL
*  LZ4LIB_VISIBILITY :
*  Control library symbols visibility.
*/
#ifndef LZ4LIB_VISIBILITY
#  if defined(__GNUC__) && (__GNUC__ >= 4)
#    define LZ4LIB_VISIBILITY __attribute__ ((visibility ("default")))
#  else
#    define LZ4LIB_VISIBILITY
#  endif
#endif
#if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT==1)
#  define LZ4LIB_API __declspec(dllexport) LZ4LIB_VISIBILITY
#elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT==1)
#  define LZ4LIB_API __declspec(dllimport) LZ4LIB_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 LZ4LIB_API LZ4LIB_VISIBILITY
#endif

/*------   Version   ------*/
#define LZ4_VERSION_MAJOR    1    /* for breaking interface changes  */
#define LZ4_VERSION_MINOR    8    /* for new (non-breaking) interface capabilities */
#define LZ4_VERSION_RELEASE  1    /* for tweaks, bug-fixes, or development */

#define LZ4_VERSION_NUMBER (LZ4_VERSION_MAJOR *100*100 + LZ4_VERSION_MINOR *100 + LZ4_VERSION_RELEASE)

#define LZ4_LIB_VERSION LZ4_VERSION_MAJOR.LZ4_VERSION_MINOR.LZ4_VERSION_RELEASE
#define LZ4_QUOTE(str) #str
#define LZ4_EXPAND_AND_QUOTE(str) LZ4_QUOTE(str)
#define LZ4_VERSION_STRING LZ4_EXPAND_AND_QUOTE(LZ4_LIB_VERSION)

LZ4LIB_API int LZ4_versionNumber (void);  /**< library version number; to be used when checking dll version */
LZ4LIB_API const char* LZ4_versionString (void);   /**< library version string; to be used when checking dll version */


/*-************************************
*  Tuning parameter
**************************************/
/*!
 * LZ4_MEMORY_USAGE :
 * Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
 * Increasing memory usage improves compression ratio
 * Reduced memory usage can improve speed, due to cache effect
 * Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache
 */
#ifndef LZ4_MEMORY_USAGE
# define LZ4_MEMORY_USAGE 14
#endif

/*-************************************
*  Simple Functions
**************************************/
/*! LZ4_compress_default() :
    Compresses 'srcSize' bytes from buffer 'src'
    into already allocated 'dst' buffer of size 'dstCapacity'.
    Compression is guaranteed to succeed if 'dstCapacity' >= LZ4_compressBound(srcSize).
    It also runs faster, so it's a recommended setting.
    If the function cannot compress 'src' into a limited 'dst' budget,
    compression stops *immediately*, and the function result is zero.
    As a consequence, 'dst' content is not valid.
    This function never writes outside 'dst' buffer, nor read outside 'source' buffer.
        srcSize : supported max value is LZ4_MAX_INPUT_VALUE
        dstCapacity : full or partial size of buffer 'dst' (which must be already allocated)
        return  : the number of bytes written into buffer 'dst' (necessarily <= dstCapacity)
                  or 0 if compression fails */
LZ4LIB_API int LZ4_compress_default(const char* src, char* dst, int srcSize, int dstCapacity);

/*! LZ4_decompress_safe() :
    compressedSize : is the exact complete size of the compressed block.
    dstCapacity : is the size of destination buffer, which must be already allocated.
    return : the number of bytes decompressed into destination buffer (necessarily <= dstCapacity)
             If destination buffer is not large enough, decoding will stop and output an error code (negative value).
             If the source stream is detected malformed, the function will stop decoding and return a negative result.
             This function is protected against buffer overflow exploits, including malicious data packets.
             It never writes outside output buffer, nor reads outside input buffer.
*/
LZ4LIB_API int LZ4_decompress_safe (const char* src, char* dst, int compressedSize, int dstCapacity);


/*-************************************
*  Advanced Functions
**************************************/
#define LZ4_MAX_INPUT_SIZE        0x7E000000   /* 2 113 929 216 bytes */
#define LZ4_COMPRESSBOUND(isize)  ((unsigned)(isize) > (unsigned)LZ4_MAX_INPUT_SIZE ? 0 : (isize) + ((isize)/255) + 16)

/*!
LZ4_compressBound() :
    Provides the maximum size that LZ4 compression may output in a "worst case" scenario (input data not compressible)
    This function is primarily useful for memory allocation purposes (destination buffer size).
    Macro LZ4_COMPRESSBOUND() is also provided for compilation-time evaluation (stack memory allocation for example).
    Note that LZ4_compress_default() compress faster when dest buffer size is >= LZ4_compressBound(srcSize)
        inputSize  : max supported value is LZ4_MAX_INPUT_SIZE
        return : maximum output size in a "worst case" scenario
              or 0, if input size is too large ( > LZ4_MAX_INPUT_SIZE)
*/
LZ4LIB_API int LZ4_compressBound(int inputSize);

/*!
LZ4_compress_fast() :
    Same as LZ4_compress_default(), but allows to select an "acceleration" factor.
    The larger the acceleration value, the faster the algorithm, but also the lesser the compression.