path: root/src/util/xxhash.h

/*
   xxHash - Extremely Fast Hash algorithm
   Header File
   Copyright (C) 2012-2016, Yann Collet.

   BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are
   met:

       * Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
       * Redistributions in binary form must reproduce the above
   copyright notice, this list of conditions and the following disclaimer
   in the documentation and/or other materials provided with the
   distribution.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

   You can contact the author at :
   - xxHash source repository : https://github.com/Cyan4973/xxHash
*/

/* Notice extracted from xxHash homepage :

xxHash is an extremely fast Hash algorithm, running at RAM speed limits.
It also successfully passes all tests from the SMHasher suite.

Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2 Duo @3GHz)

Name            Speed       Q.Score   Author
xxHash          5.4 GB/s     10
CrapWow         3.2 GB/s      2       Andrew
MumurHash 3a    2.7 GB/s     10       Austin Appleby
SpookyHash      2.0 GB/s     10       Bob Jenkins
SBox            1.4 GB/s      9       Bret Mulvey
Lookup3         1.2 GB/s      9       Bob Jenkins
SuperFastHash   1.2 GB/s      1       Paul Hsieh
CityHash64      1.05 GB/s    10       Pike & Alakuijala
FNV             0.55 GB/s     5       Fowler, Noll, Vo
CRC32           0.43 GB/s     9
MD5-32          0.33 GB/s    10       Ronald L. Rivest
SHA1-32         0.28 GB/s    10

Q.Score is a measure of quality of the hash function.
It depends on successfully passing SMHasher test set.
10 is a perfect score.

Note : SMHasher's CRC32 implementation is not the fastest one.
Other speed-oriented implementations can be faster,
especially in combination with PCLMUL instruction :
http://fastcompression.blogspot.com/2019/03/presenting-xxh3.html?showComment=1552696407071#c3490092340461170735

A 64-bit version, named XXH64, is available since r35.
It offers much better speed, but for 64-bit applications only.
Name     Speed on 64 bits    Speed on 32 bits
XXH64       13.8 GB/s            1.9 GB/s
XXH32        6.8 GB/s            6.0 GB/s
*/

#if defined (__cplusplus)
extern "C" {
#endif


#ifndef XXHASH_H_5627135585666179
#define XXHASH_H_5627135585666179 1

/* ****************************
 *  API modifier
 ******************************/
/** XXH_INLINE_ALL (and XXH_PRIVATE_API)
 *  This build macro includes xxhash functions in `static` mode
 *  in order to inline them, and remove their symbol from the public list.
 *  Inlining offers great performance improvement on small keys,
 *  and dramatic ones when length is expressed as a compile-time constant.
 *  See https://fastcompression.blogspot.com/2018/03/xxhash-for-small-keys-impressive-power.html .
 *  Methodology :
 *     #define XXH_INLINE_ALL
 *     #include "xxhash.h"
 * `xxhash.c` is automatically included.
 *  It's not useful to compile and link it as a separate object.
 */
#if defined(XXH_INLINE_ALL) || defined(XXH_PRIVATE_API)
#  ifndef XXH_STATIC_LINKING_ONLY
#    define XXH_STATIC_LINKING_ONLY
#  endif
#  if defined(__GNUC__)
#    define XXH_PUBLIC_API static __inline __attribute__((unused))
#  elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
#    define XXH_PUBLIC_API static inline
#  elif defined(_MSC_VER)
#    define XXH_PUBLIC_API static __inline
#  else
     /* this version may generate warnings for unused static functions */
#    define XXH_PUBLIC_API static
#  endif
#else
#  if defined(WIN32) && defined(_MSC_VER) && (defined(XXH_IMPORT) || defined(XXH_EXPORT))
#    ifdef XXH_EXPORT
#      define XXH_PUBLIC_API __declspec(dllexport)
#    elif XXH_IMPORT
#      define XXH_PUBLIC_API __declspec(dllimport)
#    endif
#  else
#    define XXH_PUBLIC_API   /* do nothing */
#  endif
#endif /* XXH_INLINE_ALL || XXH_PRIVATE_API */

/*! XXH_NAMESPACE, aka Namespace Emulation :
 *
 * If you want to include _and expose_ xxHash functions from within your own library,
 * but also want to avoid symbol collisions with other libraries which may also include xxHash,
 *
 * you can use XXH_NAMESPACE, to automatically prefix any public symbol from xxhash library
 * with the value of XXH_NAMESPACE (therefore, avoid NULL and numeric values).
 *
 * Note that no change is required within the calling program as long as it includes `xxhash.h` :
 * regular symbol name will be automatically translated by this header.
 */
#ifdef XXH_NAMESPACE
#  define XXH_CAT(A,B) A##B
#  define XXH_NAME2(A,B) XXH_CAT(A,B)
#  define XXH_versionNumber XXH_NAME2(XXH_NAMESPACE, XXH_versionNumber)
#  define XXH32 XXH_NAME2(XXH_NAMESPACE, XXH32)
#  define XXH32_createState XXH_NAME2(XXH_NAMESPACE, XXH32_createState)
#  define XXH32_freeState XXH_NAME2(XXH_NAMESPACE, XXH32_freeState)
#  define XXH32_reset XXH_NAME2(XXH_NAMESPACE, XXH32_reset)
#  define XXH32_update XXH_NAME2(XXH_NAMESPACE, XXH32_update)
#  define XXH32_digest XXH_NAME2(XXH_NAMESPACE, XXH32_digest)
#  define XXH32_copyState XXH_NAME2(XXH_NAMESPACE, XXH32_copyState)
#  define XXH32_canonicalFromHash XXH_NAME2(XXH_NAMESPACE, XXH32_canonicalFromHash)
#  define XXH32_hashFromCanonical XXH_NAME2(XXH_NAMESPACE, XXH32_hashFromCanonical)
#  define XXH64 XXH_NAME2(XXH_NAMESPACE, XXH64)
#  define XXH64_createState XXH_NAME2(XXH_NAMESPACE, XXH64_createState)
#  define XXH64_freeState XXH_NAME2(XXH_NAMESPACE, XXH64_freeState)
#  define XXH64_reset XXH_NAME2(XXH_NAMESPACE, XXH64_reset)
#  define XXH64_update XXH_NAME2(XXH_NAMESPACE, XXH64_update)
#  define XXH64_digest XXH_NAME2(XXH_NAMESPACE, XXH64_digest)
#  define XXH64_copyState XXH_NAME2(XXH_NAMESPACE, XXH64_copyState)
#  define XXH64_canonicalFromHash XXH_NAME2(XXH_NAMESPACE, XXH64_canonicalFromHash)
#  define XXH64_hashFromCanonical XXH_NAME2(XXH_NAMESPACE, XXH64_hashFromCanonical)
#endif


/* *************************************
*  Version
***************************************/
#define XXH_VERSION_MAJOR    0
#define XXH_VERSION_MINOR    7
#define XXH_VERSION_RELEASE  2
#define XXH_VERSION_NUMBER  (XXH_VERSION_MAJOR *100*100 + XXH_VERSION_MINOR *100 + XXH_VERSION_RELEASE)
XXH_PUBLIC_API unsigned XXH_versionNumber (void);


/* ****************************
*  Definitions
******************************/
#include <stddef.h>   /* size_t */
typedef enum { XXH_OK=0, XXH_ERROR } XXH_errorcode;


/*-**********************************************************************
*  32-bit hash
************************************************************************/
#if !defined (__VMS) \
  && (defined (__cplusplus) \
  || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
#   include <stdint.h>
    typedef uint32_t XXH32_hash_t;
#else
#   include <limits.h>
#   if UINT_MAX == 0xFFFFFFFFUL
      typedef unsigned int XXH32_hash_t;
#   else
#     if ULONG_MAX == 0xFFFFFFFFUL
        typedef unsigned long XXH32_hash_t;
#     else
#       error "unsupported platform : need a 32-bit type"
#     endif
#   endif
#endif

/*! XXH32() :
    Calculate the 32-bit hash of sequence "length" bytes stored at memory address "input".
    The memory between input & input+length must be valid (allocated and read-accessible).
    "seed" can be used to alter the result predictably.
    Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s */
XXH_PUBLIC_API XXH32_hash_t XXH32 (const void* input, size_t length, XXH32_hash_t seed);

/*******   Streaming   *******/

/*
 * Streaming functions generate the xxHash value from an incrememtal input.
 * This method is slower than single-call functions, due to state management.
 * For small inputs, prefer `XXH32()` and `XXH64()`, which are better optimized.
 *
 * XXH state must first be allocated, using XXH*_createState() .
 *
 * Start a new hash by initializing state with a seed, using XXH*_reset().
 *
 * Then, feed the hash state by calling XXH*_update() as many times as necessary.
 * The function returns an error code, with 0 meaning OK, and any other value meaning there is an error.
 *
 * Finally, a hash value can be produced anytime, by using XXH*_digest().
 * This function returns the nn-bits hash as an int or long long.
 *
 * It's still possible to continue inserting input into the hash state after a digest,
 * and generate some new hash values later on, by invoking again XXH*_digest().
 *
 * When done, release the state, using XXH*_freeState().
 */

typedef struct XXH32_state_s XXH32_state_t;   /* incomplete type */
XXH_PUBLIC_API XXH32_state_t* XXH32_createState(void);
XXH_PUBLIC_API XXH_errorcode  XXH32_freeState(XXH32_state_t* statePtr);
XXH_PUBLIC_API void XXH32_copyState(XXH32_state_t* dst_state, const XXH32_state_t* src_state);

XXH_PUBLIC_API XXH_errorcode XXH32_reset  (XXH32_state_t* statePtr, XXH32_hash_t seed);
XXH_PUBLIC_API XXH_errorcode XXH32_update (XXH32_state_t* statePtr, const void* input, size_t length);
XXH_PUBLIC_API XXH32_hash_t  XXH32_digest (const XXH32_state_t* statePtr);

/*******   Canonical representation   *******/

/* Default return values from XXH functions are basic unsigned 32 and 64 bits.
 * This the simplest and fastest format for further post-processing.
 * However, this leaves open the question of what is the order of bytes,
 * since little and big endian conventions will write the same number differently.
 *
 * The canonical representation settles this issue,
 * by mandating big-endian convention,
 * aka, the same convention as human-readable numbers (large digits first).
 * When writing hash values to storage, sending them over a network, or printing them,
 * it's highly recommended to use the canonical representation,
 * to ensure portability across a wider range of systems, present and future.
 *
 * The following functions allow transformation of hash values into and from canonical format.
 */

typedef struct { unsigned char digest[4]; } XXH32_canonical_t;
XXH_PUBLIC_API void XXH32_canonicalFromHash(XXH32_canonical_t* dst, XXH32_hash_t hash);
XXH_PUBLIC_API XXH32_hash_t XXH32_hashFromCanonical(const XXH32_canonical_t* src);


#ifndef XXH_NO_LONG_LONG
/*-**********************************************************************
*  64-bit hash
************************************************************************/
#if !defined (__VMS) \
  && (defined (__cplusplus) \
  || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
#   include <stdint.h>
    typedef uint64_t XXH64_hash_t;
#else
    /* the following type must have a width of 64-bit */
    typedef unsigned long long XXH64_hash_t;
#endif

/*! XXH64() :
 *  Returns the 64-bit hash of sequence of length @length stored at memory address @input.
 *  @seed can be used to alter the result predictably.
 *  This function runs faster on 64-bit systems, but slower on 32-bit systems (see benchmark).
 */
XXH_PUBLIC_API XXH64_hash_t XXH64 (const void* input, size_t length, XXH64_hash_t seed);

/*******   Streaming   *******/
typedef struct XXH64_state_s XXH64_state_t;   /* incomplete type */
XXH_PUBLIC_API XXH64_state_t* XXH64_createState(void);
XXH_PUBLIC_API XXH_errorcode  XXH64_freeState(XXH64_state_t* statePtr);
XXH_PUBLIC_API void XXH64_copyState(XXH64_state_t* dst_state, const XXH64_state_t* src_state);

XXH_PUBLIC_API XXH_errorcode XXH64_reset  (XXH64_state_t* statePtr, XXH64_hash_t seed);
XXH_PUBLIC_API XXH_errorcode XXH64_update (XXH64_state_t* statePtr, const void* input, size_t length);
XXH_PUBLIC_API XXH64_hash_t  XXH64_digest (const XXH64_state_t* statePtr);

/*******   Canonical representation   *******/
typedef struct { unsigned char digest[8]; } XXH64_canonical_t;
XXH_PUBLIC_API void XXH64_canonicalFromHash(XXH64_canonical_t* dst, XXH64_hash_t hash);
XXH_PUBLIC_API XXH64_hash_t XXH64_hashFromCanonical(const XXH64_canonical_t* src);


#endif  /* XXH_NO_LONG_LONG */

#endif /* XXHASH_H_5627135585666179 */



#if defined(XXH_STATIC_LINKING_ONLY) && !defined(XXHASH_H_STATIC_13879238742)
#define XXHASH_H_STATIC_13879238742
/* ************************************************************************************************
   This section contains declarations which are not guaranteed to remain stable.
   They may change in future versions, becoming incompatible with a different version of the library.
   These declarations should only be used with static linking.
   Never use them in association with dynamic linking !
*************************************************************************************************** */

/* These definitions are only present to allow
 * static allocation of XXH state, on stack or in a struct for example.
 * Never **ever** use members directly. */

struct XXH32_state_s {
   XXH32_hash_t total_len_32;
   XXH32_hash_t large_len;
   XXH32_hash_t v1;
   XXH32_hash_t v2;
   XXH32_hash_t v3;
   XXH32_hash_t v4;
   XXH32_hash_t mem32[4];
   XXH32_hash_t memsize;
   XXH32_hash_t reserved;   /* never read nor write, might be removed in a future version */
};   /* typedef'd to XXH32_state_t */


#ifndef XXH_NO_LONG_LONG  /* defined when there is no 64-bit support */

struct XXH64_state_s {
   XXH64_hash_t total_len;
   XXH64_hash_t v1;
   XXH64_hash_t v2;
   XXH64_hash_t v3;
   XXH64_hash_t v4;
   XXH64_hash_t mem64[4];
   XXH32_hash_t memsize;
   XXH32_hash_t reserved32;  /* required for padding anyway */
   XXH64_hash_t reserved64;  /* never read nor write, might be removed in a future version */
};   /* typedef'd to XXH64_state_t */

#endif  /* XXH_NO_LONG_LONG */

#if defined(XXH_INLINE_ALL) || defined(XXH_PRIVATE_API)
#  define XXH_IMPLEMENTATION
#endif

#endif  /* defined(XXH_STATIC_LINKING_ONLY) && !defined(XXHASH_H_STATIC_13879238742) */



/*-**********************************************************************
*  xxHash implementation
*  Functions implementation used to be hosted within xxhash.c .
*  However, code inlining requires to place implementation in the header file.
*  As a consequence, xxhash.c used to be included within xxhash.h .
*  But some build systems don't like *.c inclusions.
*  So the implementation is now directly integrated within xxhash.h .
*  Another small advantage is that xxhash.c is no longer required in /includes .
************************************************************************/

#if ( defined(XXH_INLINE_ALL) || defined(XXH_PRIVATE_API) \
   || defined(XXH_IMPLEMENTATION) ) && !defined(XXH_IMPLEM_13a8737387)
#  define XXH_IMPLEM_13a8737387

/* *************************************
*  Tuning parameters
***************************************/
/*!XXH_FORCE_MEMORY_ACCESS :
 * By default, access to unaligned memory is controlled by `memcpy()`, which is safe and portable.
 * Unfortunately, on some target/compiler combinations, the generated assembly is sub-optimal.
 * The below switch allow to select different access method for improved performance.
 * Method 0 (default) : use `memcpy()`. Safe and portable.
 * Method 1 : `__packed` statement. It depends on compiler extension (ie, not portable).
 *            This method is safe if your compiler supports it, and *generally* as fast or faster than `memcpy`.
 * Method 2 : direct access. This method doesn't depend on compiler but violate C standard.
 *            It can generate buggy code on targets which do not support unaligned memory accesses.
 *            But in some circumstances, it's the only known way to get the most performance (ie GCC + ARMv6)
 * See http://stackoverflow.com/a/32095106/646947 for details.
 * Prefer these methods in priority order (0 > 1 > 2)
 */
#ifndef XXH_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
#  if !defined(__clang__) && defined(__GNUC__) && defined(__ARM_FEATURE_UNALIGNED) && defined(__ARM_ARCH) && (__ARM_ARCH == 6)
#    define XXH_FORCE_MEMORY_ACCESS 2
#  elif !defined(__clang__) && ((defined(__INTEL_COMPILER) && !defined(_WIN32)) || \
  (defined(__GNUC__) && (defined(__ARM_ARCH) && __ARM_ARCH >= 7)))
#    define XXH_FORCE_MEMORY_ACCESS 1
#  endif
#endif

/*!XXH_ACCEPT_NULL_INPUT_POINTER :
 * If input pointer is NULL, xxHash default behavior is to dereference it, triggering a segfault.
 * When this macro is enabled, xxHash actively checks input for null pointer.
 * It it is, result for null input pointers is the same as a null-length input.
 */
#ifndef XXH_ACCEPT_NULL_INPUT_POINTER   /* can be defined externally */
#  define XXH_ACCEPT_NULL_INPUT_POINTER 0
#endif

/*!XXH_FORCE_ALIGN_CHECK :
 * This is a minor performance trick, only useful with lots of very small keys.
 * It means : check for aligned/unaligned input.
 * The check costs one initial branch per hash;
 * set it to 0 when the input is guaranteed to be aligned,
 * or when alignment doesn't matter for performance.
 */
#ifndef XXH_FORCE_ALIGN_CHECK /* can be defined externally */
#  if defined(__i386) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_X64)
#    define XXH_FORCE_ALIGN_CHECK 0
#  else
#    define XXH_FORCE_ALIGN_CHECK 1
#  endif
#endif

/*!XXH_REROLL:
 * Whether to reroll XXH32_finalize, and XXH64_finalize,
 * instead of using an unrolled jump table/if statement loop.
 *
 * This is automatically defined on -Os/-Oz on GCC and Clang. */
#ifndef XXH_REROLL
#  if defined(__OPTIMIZE_SIZE__)
#    define XXH_REROLL 1
#  else
#    define XXH_REROLL 0
#  endif
#endif


/* *************************************
*  Includes & Memory related functions
***************************************/
/*! Modify the local functions below should you wish to use some other memory routines
*   for malloc(), free() */
#include <stdlib.h>
static void* XXH_malloc(size_t s) { return malloc(s); }
static void  XXH_free  (void* p)  { free(p); }
/*! and for memcpy() */
#include <string.h>
static void* XXH_memcpy(void* dest, const void* src, size_t size) { return memcpy(dest,src,size); }

#include <limits.h>   /* ULLONG_MAX */


/* *************************************
*  Compiler Specific Options
***************************************/
#ifdef _MSC_VER    /* Visual Studio */
#  pragma warning(disable : 4127)      /* disable: C4127: conditional expression is constant */
#  define XXH_FORCE_INLINE static __forceinline
#  define XXH_NO_INLINE static __declspec(noinline)
#else
#  if defined (__cplusplus) || defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
#    ifdef __GNUC__
#      define XXH_FORCE_INLINE static inline __attribute__((always_inline))
#      define XXH_NO_INLINE static __attribute__((noinline))
#    else
#      define XXH_FORCE_INLINE static inline
#      define XXH_NO_INLINE static
#    endif
#  else
#    define XXH_FORCE_INLINE static
#    define XXH_NO_INLINE static
#  endif /* __STDC_VERSION__ */
#endif



/* *************************************
*  Debug
***************************************/
/* DEBUGLEVEL is expected to be defined externally,
 * typically through compiler command line.
 * Value must be a number. */
#ifndef DEBUGLEVEL
#  define DEBUGLEVEL 0
#endif

#if (DEBUGLEVEL>=1)
#  include <assert.h>   /* note : can still be disabled with NDEBUG */
#  define XXH_ASSERT(c)   assert(c)
#else
#  define XXH_ASSERT(c)   ((void)0)
#endif

/* note : use after variable declarations */
#define XXH_STATIC_ASSERT(c)  { enum { XXH_sa = 1/(int)(!!(c)) }; }


/* *************************************
*  Basic Types
***************************************/
#if !defined (__VMS) \
 && (defined (__cplusplus) \
 || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
# include <stdint.h>
  typedef uint8_t  xxh_u8;
#else
  typedef unsigned char      xxh_u8;
#endif
typedef XXH32_hash_t xxh_u32;


/* ***   Memory access   *** */

#if (defined(XXH_FORCE_MEMORY_ACCESS) && (XXH_FORCE_MEMORY_ACCESS==2))

/* Force direct memory access. Only works on CPU which support unaligned memory access in hardware */
static xxh_u32 XXH_read32(const void* memPtr) { return *(const xxh_u32*) memPtr; }

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

/* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
/* currently only defined for gcc and icc */
typedef union { xxh_u32 u32; } __attribute__((packed)) unalign;
static xxh_u32 XXH_read32(const void* ptr) { return ((const unalign*)ptr)->u32; }

#else

/* portable and safe solution. Generally efficient.
 * see : http://stackoverflow.com/a/32095106/646947
 */
static xxh_u32 XXH_read32(const void* memPtr)
{
    xxh_u32 val;
    memcpy(&val, memPtr, sizeof(val));
    return val;
}

#endif   /* XXH_FORCE_DIRECT_MEMORY_ACCESS */


/* ***   Endianess   *** */
typedef enum { XXH_bigEndian=0, XXH_littleEndian=1 } XXH_endianess;

/* XXH_CPU_LITTLE_ENDIAN can be defined externally, for example on the compiler command line */
#ifndef XXH_CPU_LITTLE_ENDIAN
#  if defined(_WIN32) /* Windows is always little endian */ \
     || defined(__LITTLE_ENDIAN__) \
     || (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
#    define XXH_CPU_LITTLE_ENDIAN 1
#  elif defined(__BIG_ENDIAN__) \
     || (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
#    define XXH_CPU_LITTLE_ENDIAN 0
#  else
static int XXH_isLittleEndian(void)
{
    const union { xxh_u32 u; xxh_u8 c[4]; } one = { 1 };   /* don't use static : performance detrimental  */
    return one.c[0];
}
#   define XXH_CPU_LITTLE_ENDIAN   XXH_isLittleEndian()
#  endif
#endif




/* ****************************************
*  Compiler-specific Functions and Macros
******************************************/
#define XXH_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)

#ifndef __has_builtin
#  define __has_builtin(x) 0
#endif

#if !defined(NO_CLANG_BUILTIN) && __has_builtin(__builtin_rotateleft32) && __has_builtin(__builtin_rotateleft64)
#  define XXH_rotl32 __builtin_rotateleft32
#  define XXH_rotl64 __builtin_rotateleft64
/* Note : although _rotl exists for minGW (GCC under windows), performance seems poor */
#elif defined(_MSC_VER)
#  define XXH_rotl32(x,r) _rotl(x,r)
#  define XXH_rotl64(x,r) _rotl64(x,r)
#else
#  define XXH_rotl32(x,r) (((x) << (r)) | ((x) >> (32 - (r))))
#  define XXH_rotl64(x,r) (((x) << (r)) | ((x) >> (64 - (r))))
#endif

#if defined(_MSC_VER)     /* Visual Studio */
#  define XXH_swap32 _byteswap_ulong
#elif XXH_GCC_VERSION >= 403
#  define XXH_swap32 __builtin_bswap32
#else
static xxh_u32 XXH_swap32 (xxh_u32 x)
{
    return  ((x << 24) & 0xff000000 ) |
            ((x <<  8) & 0x00ff0000 ) |
            ((x >>  8) & 0x0000ff00 ) |
            ((x >> 24) & 0x000000ff );
}
#endif


/* ***************************
*  Memory reads
*****************************/
typedef enum { XXH_aligned, XXH_unaligned } XXH_alignment;

XXH_FORCE_INLINE xxh_u32 XXH_readLE32(const void* ptr)
{
    return XXH_CPU_LITTLE_ENDIAN ? XXH_read32(ptr) : XXH_swap32(XXH_read32(ptr));
}

static xxh_u32 XXH_readBE32(const void* ptr)
{
    return XXH_CPU_LITTLE_ENDIAN ? XXH_swap32(XXH_read32(ptr)) : XXH_read32(ptr);
}

XXH_FORCE_INLINE xxh_u32
XXH_readLE32_align(const void* ptr, XXH_alignment align)
{
    if (align==XXH_unaligned) {
        return XXH_readLE32(ptr);
    } else {
        return XXH_CPU_LITTLE_ENDIAN ? *(const xxh_u32*)ptr : XXH_swap32(*(const xxh_u32*)ptr);
    }
}


/* *************************************
*  Misc
***************************************/
XXH_PUBLIC_API unsigned XXH_versionNumber (void) { return XXH_VERSION_NUMBER; }


/* *******************************************************************
*  32-bit hash functions
*********************************************************************/
static const xxh_u32 PRIME32_1 = 0x9E3779B1U;   /* 0b10011110001101110111100110110001 */
static const xxh_u32 PRIME32_2 = 0x85EBCA77U;   /* 0b10000101111010111100101001110111 */
static const xxh_u32 PRIME32_3 = 0xC2B2AE3DU;   /* 0b11000010101100101010111000111101 */
static const xxh_u32 PRIME32_4 = 0x27D4EB2FU;   /* 0b00100111110101001110101100101111 */
static const xxh_u32 PRIME32_5 = 0x165667B1U;   /* 0b00010110010101100110011110110001 */

static xxh_u32 XXH32_round(xxh_u32 acc, xxh_u32 input)
{
    acc += input * PRIME32_2;
    acc  = XXH_rotl32(acc, 13);
    acc *= PRIME32_1;
#if defined(__GNUC__) && defined(__SSE4_1__) && !defined(XXH_ENABLE_AUTOVECTORIZE)
    /* UGLY HACK:
     * This inline assembly hack forces acc into a normal register. This is the
     * only thing that prevents GCC and Clang from autovectorizing the XXH32 loop
     * (pragmas and attributes don't work for some resason) without globally
     * disabling SSE4.1.
     *
     * The reason we want to avoid vectorization is because despite working on
     * 4 integers at a time, there are multiple factors slowing XXH32 down on
     * SSE4:
     * - There's a ridiculous amount of lag from pmulld (10 cycles of latency on newer chips!)
     *   making it slightly slower to multiply four integers at once compared to four
     *   integers independently. Even when pmulld was fastest, Sandy/Ivy Bridge, it is
     *   still not worth it to go into SSE just to multiply unless doing a long operation.
     *
     * - Four instructions are required to rotate,
     *      movqda tmp,  v // not required with VEX encoding
     *      pslld  tmp, 13 // tmp <<= 13
     *      psrld  v,   19 // x >>= 19
     *      por    v,  tmp // x |= tmp
     *   compared to one for scalar:
     *      roll   v, 13    // reliably fast across the board
     *      shldl  v, v, 13 // Sandy Bridge and later prefer this for some reason
     *
     * - Instruction level parallelism is actually more beneficial here because the
     *   SIMD actually serializes this operation: While v1 is rotating, v2 can load data,
     *   while v3 can multiply. SSE forces them to operate together.
     *
     * How this hack works:
     * __asm__(""       // Declare an assembly block but don't declare any instructions
     *          :       // However, as an Input/Output Operand,
     *          "+r"    // constrain a read/write operand (+) as a general purpose register (r).
     *          (acc)   // and set acc as the operand
     * );
     *
     * Because of the 'r', the compiler has promised that seed will be in a
     * general purpose register and the '+' says that it will be 'read/write',
     * so it has to assume it has changed. It is like volatile without all the
     * loads and stores.
     *
     * Since the argument has to be in a normal register (not an SSE register),
     * each time XXH32_round is called, it is impossible to vectorize. */
    __asm__("" : "+r" (acc));
#endif
    return acc;
}

/* mix all bits */
static xxh_u32 XXH32_avalanche(xxh_u32 h32)
{
    h32 ^= h32 >> 15;
    h32 *= PRIME32_2;
    h32 ^= h32 >> 13;
    h32 *= PRIME32_3;
    h32 ^= h32 >> 16;
    return(h32);
}

#define XXH_get32bits(p) XXH_readLE32_align(p, align)

static xxh_u32
XXH32_finalize(xxh_u32 h32, const xxh_u8* ptr, size_t len, XXH_alignment align)
{
#define PROCESS1               \
    h32 += (*ptr++) * PRIME32_5; \
    h32 = XXH_rotl32(h32, 11) * PRIME32_1 ;

#define PROCESS4                         \
    h32 += XXH_get32bits(ptr) * PRIME32_3; \
    ptr+=4;                                \
    h32  = XXH_rotl32(h32, 17) * PRIME32_4 ;

    /* Compact rerolled version */
    if (XXH_REROLL) {
        len &= 15;
        while (len >= 4) {
            PROCESS4;
            len -= 4;
        }
        while (len > 0) {
            PROCESS1;
            --len;
        }
        return XXH32_avalanche(h32);
    } else {
         switch(len&15) /* or switch(bEnd - p) */ {
           case 12:      PROCESS4;
                         /* fallthrough */
           case 8:       PROCESS4;
                         /* fallthrough */
           case 4:       PROCESS4;
                         return XXH32_avalanche(h32);

           case 13:      PROCESS4;
                         /* fallthrough */
           case 9:       PROCESS4;
                         /* fallthrough */
           case 5:       PROCESS4;
                         PROCESS1;
                         return XXH32_avalanche(h32);

           case 14:      PROCESS4;
                         /* fallthrough */
           case 10:      PROCESS4;
                         /* fallthrough */
           case 6:       PROCESS4;
                         PROCESS1;
                         PROCESS1;
                         return XXH32_avalanche(h32);

           case 15:      PROCESS4;
                         /* fallthrough */
           case 11:      PROCESS4;
                         /* fallthrough */
           case 7:       PROCESS4;
                         /* fallthrough */
           case 3:       PROCESS1;
                         /* fallthrough */
           case 2:       PROCESS1;
                         /* fallthrough */
           case 1:       PROCESS1;
                         /* fallthrough */
           case 0:       return XXH32_avalanche(h32);
        }
        XXH_ASSERT(0);
        return h32;   /* reaching this point is deemed impossible */
    }
}

XXH_FORCE_INLINE xxh_u32
XXH32_endian_align(const xxh_u8* input, size_t len, xxh_u32 seed, XXH_alignment align)
{
    const xxh_u8* bEnd = input + len;
    xxh_u32 h32;

#if defined(XXH_ACCEPT_NULL_INPUT_POINTER) && (XXH_ACCEPT_NULL_INPUT_POINTER>=1)
    if (input==NULL) {
        len=0;
        bEnd=input=(const xxh_u8*)(size_t)16;
    }
#endif

    if (len>=16) {
        const xxh_u8* const limit = bEnd - 15;
        xxh_u32 v1 = seed + PRIME32_1 + PRIME32_2;
        xxh_u32 v2 = seed + PRIME32_2;
        xxh_u32 v3 = seed + 0;
        xxh_u32 v4 = seed - PRIME32_1;

        do {
            v1 = XXH32_round(v1, XXH_get32bits(input)); input += 4;
            v2 = XXH32_round(v2, XXH_get32bits(input)); input += 4;
            v3 = XXH32_round(v3, XXH_get32bits(input)); input += 4;
            v4 = XXH32_round(v4, XXH_get32bits(input)); input += 4;
        } while (input < limit);

        h32 = XXH_rotl32(v1, 1)  + XXH_rotl32(v2, 7)
            + XXH_rotl32(v3, 12) + XXH_rotl32(v4, 18);
    } else {
        h32  = seed + PRIME32_5;
    }

    h32 += (xxh_u32)len;

    return XXH32_finalize(h32, input, len&15, align);
}


XXH_PUBLIC_API XXH32_hash_t XXH32 (const void* input, size_t len, XXH32_hash_t seed)
{
#if 0
    /* Simple version, good for code maintenance, but unfortunately slow for small inputs */
    XXH32_state_t state;
    XXH32_reset(&state, seed);
    XXH32_update(&state, (const xxh_u8*)input, len);
    return XXH32_digest(&state);

#else

    if (XXH_FORCE_ALIGN_CHECK) {
        if ((((size_t)input) & 3) == 0) {   /* Input is 4-bytes aligned, leverage the speed benefit */
            return XXH32_endian_align((const xxh_u8*)input, len, seed, XXH_aligned);
    }   }

    return XXH32_endian_align((const xxh_u8*)input, len, seed, XXH_unaligned);
#endif
}



/*******   Hash streaming   *******/

XXH_PUBLIC_API XXH32_state_t* XXH32_createState(void)
{
    return (XXH32_state_t*)XXH_malloc(sizeof(XXH32_state_t));
}
XXH_PUBLIC_API XXH_errorcode XXH32_freeState(XXH32_state_t* statePtr)
{
    XXH_free(statePtr);
    return XXH_OK;
}

XXH_PUBLIC_API void XXH32_copyState(XXH32_state_t* dstState, const XXH32_state_t* srcState)
{
    memcpy(dstState, srcState, sizeof(*dstState));
}

XXH_PUBLIC_API XXH_errorcode XXH32_reset(XXH32_state_t* statePtr, XXH32_hash_t seed)
{
    XXH32_state_t state;   /* using a local state to memcpy() in order to avoid strict-aliasing warnings */
    memset(&state, 0, sizeof(state));
    state.v1 = seed + PRIME32_1 + PRIME32_2;
    state.v2 = seed + PRIME32_2;
    state.v3 = seed + 0;
    state.v4 = seed - PRIME32_1;
    /* do not write into reserved, planned to be removed in a future version */
    memcpy(statePtr, &state, sizeof(state) - sizeof(state.reserved));
    return XXH_OK;
}


XXH_PUBLIC_API XXH_errorcode
XXH32_update(XXH32_state_t* state, const void* input, size_t len)
{
    if (input==NULL)
#if defined(XXH_ACCEPT_NULL_INPUT_POINTER) && (XXH_ACCEPT_NULL_INPUT_POINTER>=1)
        return XXH_OK;
#else
        return XXH_ERROR;
#endif

    {   const xxh_u8* p = (const xxh_u8*)input;
        const xxh_u8* const bEnd = p + len;

        state->total_len_32 += (XXH32_hash_t)len;
        state->large_len |= (XXH32_hash_t)((len>=16) | (state->total_len_32>=16));

        if (state->memsize + len < 16)  {   /* fill in tmp buffer */
            XXH_memcpy((xxh_u8*)(state->mem32) + state->memsize, input, len);
            state->memsize += (XXH32_hash_t)len;
            return XXH_OK;
        }

        if (state->memsize) {   /* some data left from previous update */
            XXH_memcpy((xxh_u8*)(state->mem32) + state->memsize, input, 16-state->memsize);
            {   const xxh_u32* p32 = state->mem32;
                state->v1 = XXH32_round(state->v1, XXH_readLE32(p32)); p32++;
                state->v2 = XXH32_round(state->v2, XXH_readLE32(p32)); p32++;
                state->v3 = XXH32_round(state->v3, XXH_readLE32(p32)); p32++;
                state->v4 = XXH32_round(state->v4, XXH_readLE32(p32));
            }
            p += 16-state->memsize;
            state->memsize = 0;
        }

        if (p <= bEnd-16) {
            const xxh_u8* const limit = bEnd - 16;
            xxh_u32 v1 = state->v1;
            xxh_u32 v2 = state->v2;
            xxh_u32 v3 = state->v3;
            xxh_u32 v4 = state->v4;

            do {
                v1 = XXH32_round(v1, XXH_readLE32(p)); p+=4;
                v2 = XXH32_round(v2, XXH_readLE32(p)); p+=4;
                v3 = XXH32_round(v3, XXH_readLE32(p)); p+=4;
                v4 = XXH32_round(v4, XXH_readLE32(p)); p+=4;
            } while (p<=limit);

            state->v1 = v1;
            state->v2 = v2;
            state->v3 = v3;
            state->v4 = v4;
        }

        if (p < bEnd) {
            XXH_memcpy(state->mem32, p, (size_t)(bEnd-p));
            state->memsize = (unsigned)(bEnd-p);
        }
    }

    return XXH_OK;
}


XXH_PUBLIC_API XXH32_hash_t XXH32_digest (const XXH32_state_t* state)
{
    xxh_u32 h32;

    if (state->large_len) {
        h32 = XXH_rotl32(state->v1, 1)
            + XXH_rotl32(state->v2, 7)
            + XXH_rotl32(state->v3, 12)
            + XXH_rotl32(state->v4, 18);
    } else {
        h32 = state->v3 /* == seed */ + PRIME32_5;
    }

    h32 += state->total_len_32;

    return XXH32_finalize(h32, (const xxh_u8*)state->mem32, state->memsize, XXH_aligned);
}


/*******   Canonical representation   *******/

/*! Default XXH result types are basic unsigned 32 and 64 bits.
*   The canonical representation follows human-readable write convention, aka big-endian (large digits first).
*   These functions allow transformation of hash result into and from its canonical format.
*   This way, hash values can be written into a file or buffer, remaining comparable across different systems.
*/

XXH_PUBLIC_API void XXH32_canonicalFromHash(XXH32_canonical_t* dst, XXH32_hash_t hash)
{
    XXH_STATIC_ASSERT(sizeof(XXH32_canonical_t) == sizeof(XXH32_hash_t));
    if (XXH_CPU_LITTLE_ENDIAN) hash = XXH_swap32(hash);
    memcpy(dst, &hash, sizeof(*dst));
}

XXH_PUBLIC_API XXH32_hash_t XXH32_hashFromCanonical(const XXH32_canonical_t* src)
{
    return XXH_readBE32(src);
}


#ifndef XXH_NO_LONG_LONG

/* *******************************************************************
*  64-bit hash functions
*********************************************************************/

/*******   Memory access   *******/

typedef XXH64_hash_t xxh_u64;


/*! XXH_REROLL_XXH64:
 * Whether to reroll the XXH64_finalize() loop.
 *
 * Just like XXH32, we can unroll the XXH64_finalize() loop. This can be a performance gain
 * on 64-bit hosts, as only one jump is required.
 *
 * However, on 32-bit hosts, because arithmetic needs to be done with two 32-bit registers,
 * and 64-bit arithmetic needs to be simulated, it isn't beneficial to unroll. The code becomes
 * ridiculously large (the largest function in the binary on i386!), and rerolling it saves
 * anywhere from 3kB to 20kB. It is also slightly faster because it fits into cache better
 * and is more likely to be inlined by the compiler.
 *
 * If XXH_REROLL is defined, this is ignored and the loop is always rerolled. */
#ifndef XXH_REROLL_XXH64
#  if (defined(__ILP32__) || defined(_ILP32)) /* ILP32 is often defined on 32-bit GCC family */ \
   || !(defined(__x86_64__) || defined(_M_X64) || defined(_M_AMD64) /* x86-64 */ \
     || defined(_M_ARM64) || defined(__aarch64__) || defined(__arm64__) /* aarch64 */ \
     || defined(__PPC64__) || defined(__PPC64LE__) || defined(__ppc64__) || defined(__powerpc64__) /* ppc64 */ \
     || defined(__mips64__) || defined(__mips64)) /* mips64 */ \
   || (!defined(SIZE_MAX) || SIZE_MAX < ULLONG_MAX) /* check limits */
#    define XXH_REROLL_XXH64 1
#  else
#    define XXH_REROLL_XXH64 0
#  endif
#endif /* !defined(XXH_REROLL_XXH64) */

#if (defined(XXH_FORCE_MEMORY_ACCESS) && (XXH_FORCE_MEMORY_ACCESS==2))

/* Force direct memory access. Only works on CPU which support unaligned memory access in hardware */
static xxh_u64 XXH_read64(const void* memPtr) { return *(const xxh_u64*) memPtr; }

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

/* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
/* currently only defined for gcc and icc */
typedef union { xxh_u32 u32; xxh_u64 u64; } __attribute__((packed)) unalign64;
static xxh_u64 XXH_read64(const void* ptr) { return ((const unalign64*)ptr)->u64; }

#else

/* portable and safe solution. Generally efficient.
 * see : http://stackoverflow.com/a/32095106/646947
 */

static xxh_u64 XXH_read64(const void* memPtr)
{
    xxh_u64 val;
    memcpy(&val, memPtr, sizeof(val));
    return val;
}

#endif   /* XXH_FORCE_DIRECT_MEMORY_ACCESS */

#if defined(_MSC_VER)     /* Visual Studio */
#  define XXH_swap64 _byteswap_uint64
#elif XXH_GCC_VERSION >= 403
#  define XXH_swap64 __builtin_bswap64
#else
static xxh_u64 XXH_swap64 (xxh_u64 x)
{
    return  ((x << 56) & 0xff00000000000000ULL) |
            ((x << 40) & 0x00ff000000000000ULL) |
            ((x << 24) & 0x0000ff0000000000ULL) |
            ((x << 8)  & 0x000000ff00000000ULL) |
            ((x >> 8)  & 0x00000000ff000000ULL) |
            ((x >> 24) & 0x0000000000ff0000ULL) |
            ((x >> 40) & 0x000000000000ff00ULL) |
            ((x >> 56) & 0x00000000000000ffULL);
}
#endif

XXH_FORCE_INLINE xxh_u64 XXH_readLE64(const void* ptr)
{
    return XXH_CPU_LITTLE_ENDIAN ? XXH_read64(ptr) : XXH_swap64(XXH_read64(ptr));
}

static xxh_u64 XXH_readBE64(const void* ptr)
{
    return XXH_CPU_LITTLE_ENDIAN ? XXH_swap64(XXH_read64(ptr)) : XXH_read64(ptr);
}

XXH_FORCE_INLINE xxh_u64
XXH_readLE64_align(const void* ptr, XXH_alignment align)
{
    if (align==XXH_unaligned)
        return XXH_readLE64(ptr);
    else
        return XXH_CPU_LITTLE_ENDIAN ? *(const xxh_u64*)ptr : XXH_swap64(*(const xxh_u64*)ptr);
}


/*******   xxh64   *******/

static const xxh_u64 PRIME64_1 = 0x9E3779B185EBCA87ULL;   /* 0b1001111000110111011110011011000110000101111010111100101010000111 */
static const xxh_u64 PRIME64_2 = 0xC2B2AE3D27D4EB4FULL;   /* 0b1100001010110010101011100011110100100111110101001110101101001111 */
static const xxh_u64 PRIME64_3 = 0x165667B19E3779F9ULL;   /* 0b0001011001010110011001111011000110011110001101110111100111111001 */
static const xxh_u64 PRIME64_4 = 0x85EBCA77C2B2AE63ULL;   /* 0b1000010111101011110010100111011111000010101100101010111001100011 */
static const xxh_u64 PRIME64_5 = 0x27D4EB2F165667C5ULL;   /* 0b0010011111010100111010110010111100010110010101100110011111000101 */

static xxh_u64 XXH64_round(xxh_u64 acc, xxh_u64 input)
{
    acc += input * PRIME64_2;
    acc  = XXH_rotl64(acc, 31);
    acc *= PRIME64_1;
    return acc;
}

static xxh_u64 XXH64_mergeRound(xxh_u64 acc, xxh_u64 val)
{
    val  = XXH64_round(0, val);
    acc ^= val;
    acc  = acc * PRIME64_1 + PRIME64_4;
    return acc;
}

static xxh_u64 XXH64_avalanche(xxh_u64 h64)
{
    h64 ^= h64 >> 33;
    h64 *= PRIME64_2;
    h64 ^= h64 >> 29;
    h64 *= PRIME64_3;
    h64 ^= h64 >> 32;
    return h64;
}


#define XXH_get64bits(p) XXH_readLE64_align(p, align)

static xxh_u64
XXH64_finalize(xxh_u64 h64, const xxh_u8* ptr, size_t len, XXH_alignment align)
{
#define PROCESS1_64            \
    h64 ^= (*ptr++) * PRIME64_5; \
    h64 = XXH_rotl64(h64, 11) * PRIME64_1;

#define PROCESS4_64          \
    h64 ^= (xxh_u64)(XXH_get32bits(ptr)) * PRIME64_1; \
    ptr+=4;                    \
    h64 = XXH_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;

#define PROCESS8_64 {        \
    xxh_u64 const k1 = XXH64_round(0, XXH_get64bits(ptr)); \
    ptr+=8;                    \
    h64 ^= k1;               \
    h64  = XXH_rotl64(h64,27) * PRIME64_1 + PRIME64_4; \
}

    /* Rerolled version for 32-bit targets is faster and much smaller. */
    if (XXH_REROLL || XXH_REROLL_XXH64) {
        len &= 31;
        while (len >= 8) {
            PROCESS8_64;
            len -= 8;
        }
        if (len >= 4) {
            PROCESS4_64;
            len -= 4;
        }
        while (len > 0) {
            PROCESS1_64;
            --len;
        }
         return  XXH64_avalanche(h64);
    } else {
        switch(len & 31) {
           case 24: PROCESS8_64;
                         /* fallthrough */
           case 16: PROCESS8_64;
                         /* fallthrough */
           case  8: PROCESS8_64;
                    return XXH64_avalanche(h64);

           case 28: PROCESS8_64;
                         /* fallthrough */
           case 20: PROCESS8_64;
                         /* fallthrough */
           case 12: PROCESS8_64;
                         /* fallthrough */
           case  4: PROCESS4_64;
                    return XXH64_avalanche(h64);

           case 25: PROCESS8_64;
                         /* fallthrough */
           case 17: PROCESS8_64;
                         /* fallthrough */
           case  9: PROCESS8_64;
                    PROCESS1_64;
                    return XXH64_avalanche(h64);

           case 29: PROCESS8_64;
                         /* fallthrough */
           case 21: PROCESS8_64;
                         /* fallthrough */
           case 13: PROCESS8_64;
                         /* fallthrough */
           case  5: PROCESS4_64;
                    PROCESS1_64;
                    return XXH64_avalanche(h64);

           case 26: PROCESS8_64;
                         /* fallthrough */
           case 18: PROCESS8_64;
                         /* fallthrough */
           case 10: PROCESS8_64;
                    PROCESS1_64;
                    PROCESS1_64;
                    return XXH64_avalanche(h64);

           case 30: PROCESS8_64;
                         /* fallthrough */
           case 22: PROCESS8_64;
                         /* fallthrough */
           case 14: PROCESS8_64;
                         /* fallthrough */
           case  6: PROCESS4_64;
                    PROCESS1_64;
                    PROCESS1_64;
                    return XXH64_avalanche(h64);

           case 27: PROCESS8_64;
                         /* fallthrough */
           case 19: PROCESS8_64;
                         /* fallthrough */
           case 11: PROCESS8_64;
                    PROCESS1_64;
                    PROCESS1_64;
                    PROCESS1_64;
                    return XXH64_avalanche(h64);

           case 31: PROCESS8_64;
                         /* fallthrough */
           case 23: PROCESS8_64;
                         /* fallthrough */
           case 15: PROCESS8_64;
                         /* fallthrough */
           case  7: PROCESS4_64;
                         /* fallthrough */
           case  3: PROCESS1_64;
                         /* fallthrough */
           case  2: PROCESS1_64;
                         /* fallthrough */
           case  1: PROCESS1_64;
                         /* fallthrough */
           case  0: return XXH64_avalanche(h64);
        }
    }
    /* impossible to reach */
    XXH_ASSERT(0);
    return 0;  /* unreachable, but some compilers complain without it */
}

XXH_FORCE_INLINE xxh_u64
XXH64_endian_align(const xxh_u8* input, size_t len, xxh_u64 seed, XXH_alignment align)
{
    const xxh_u8* bEnd = input + len;
    xxh_u64 h64;

#if defined(XXH_ACCEPT_NULL_INPUT_POINTER) && (XXH_ACCEPT_NULL_INPUT_POINTER>=1)
    if (input==NULL) {
        len=0;
        bEnd=input=(const xxh_u8*)(size_t)32;
    }
#endif

    if (len>=32) {
        const xxh_u8* const limit = bEnd - 32;
        xxh_u64 v1 = seed + PRIME64_1 + PRIME64_2;
        xxh_u64 v2 = seed + PRIME64_2;
        xxh_u64 v3 = seed + 0;
        xxh_u64 v4 = seed - PRIME64_1;

        do {
            v1 = XXH64_round(v1, XXH_get64bits(input)); input+=8;
            v2 = XXH64_round(v2, XXH_get64bits(input)); input+=8;
            v3 = XXH64_round(v3, XXH_get64bits(input)); input+=8;
            v4 = XXH64_round(v4, XXH_get64bits(input)); input+=8;
        } while (input<=limit);

        h64 = XXH_rotl64(v1, 1) + XXH_rotl64(v2, 7) + XXH_rotl64(v3, 12) + XXH_rotl64(v4, 18);
        h64 = XXH64_mergeRound(h64, v1);
        h64 = XXH64_mergeRound(h64, v2);
        h64 = XXH64_mergeRound(h64, v3);
        h64 = XXH64_mergeRound(h64, v4);

    } else {
        h64  = seed + PRIME64_5;
    }

    h64 += (xxh_u64) len;

    return XXH64_finalize(h64, input, len, align);
}


XXH_PUBLIC_API XXH64_hash_t XXH64 (const void* input, size_t len, XXH64_hash_t seed)
{
#if 0
    /* Simple version, good for code maintenance, but unfortunately slow for small inputs */
    XXH64_state_t state;
    XXH64_reset(&state, seed);
    XXH64_update(&state, (const xxh_u8*)input, len);
    return XXH64_digest(&state);

#else

    if (XXH_FORCE_ALIGN_CHECK) {
        if ((((size_t)input) & 7)==0) {  /* Input is aligned, let's leverage the speed advantage */
            return XXH64_endian_align((const xxh_u8*)input, len, seed, XXH_aligned);
    }   }

    return XXH64_endian_align((const xxh_u8*)input, len, seed, XXH_unaligned);

#endif
}

/*******   Hash Streaming   *******/

XXH_PUBLIC_API XXH64_state_t* XXH64_createState(void)
{
    return (XXH64_state_t*)XXH_malloc(sizeof(XXH64_state_t));
}
XXH_PUBLIC_API XXH_errorcode XXH64_freeState(XXH64_state_t* statePtr)
{
    XXH_free(statePtr);
    return XXH_OK;
}

XXH_PUBLIC_API void XXH64_copyState(XXH64_state_t* dstState, const XXH64_state_t* srcState)
{
    memcpy(dstState, srcState, sizeof(*dstState));
}

XXH_PUBLIC_API XXH_errorcode XXH64_reset(XXH64_state_t* statePtr, XXH64_hash_t seed)
{
    XXH64_state_t state;   /* using a local state to memcpy() in order to avoid strict-aliasing warnings */
    memset(&state, 0, sizeof(state));
    state.v1 = seed + PRIME64_1 + PRIME64_2;
    state.v2 = seed + PRIME64_2;
    state.v3 = seed + 0;
    state.v4 = seed - PRIME64_1;
     /* do not write into reserved64, might be removed in a future version */
    memcpy(statePtr, &state, sizeof(state) - sizeof(state.reserved64));
    return XXH_OK;
}

XXH_PUBLIC_API XXH_errorcode
XXH64_update (XXH64_state_t* state, const void* input, size_t len)
{
    if (input==NULL)
#if defined(XXH_ACCEPT_NULL_INPUT_POINTER) && (XXH_ACCEPT_NULL_INPUT_POINTER>=1)
        return XXH_OK;
#else
        return XXH_ERROR;
#endif

    {   const xxh_u8* p = (const xxh_u8*)input;
        const xxh_u8* const bEnd = p + len;

        state->total_len += len;

        if (state->memsize + len < 32) {  /* fill in tmp buffer */
            XXH_memcpy(((xxh_u8*)state->mem64) + state->memsize, input, len);
            state->memsize += (xxh_u32)len;
            return XXH_OK;
        }

        if (state->memsize) {   /* tmp buffer is full */
            XXH_memcpy(((xxh_u8*)state->mem64) + state->memsize, input, 32-state->memsize);
            state->v1 = XXH64_round(state->v1, XXH_readLE64(state->mem64+0));
            state->v2 = XXH64_round(state->v2, XXH_readLE64(state->mem64+1));
            state->v3 = XXH64_round(state->v3, XXH_readLE64(state->mem64+2));
            state->v4 = XXH64_round(state->v4, XXH_readLE64(state->mem64+3));
            p += 32-state->memsize;
            state->memsize = 0;
        }

        if (p+32 <= bEnd) {
            const xxh_u8* const limit = bEnd - 32;
            xxh_u64 v1 = state->v1;
            xxh_u64 v2 = state->v2;
            xxh_u64 v3 = state->v3;
            xxh_u64 v4 = state->v4;

            do {
                v1 = XXH64_round(v1, XXH_readLE64(p)); p+=8;
                v2 = XXH64_round(v2, XXH_readLE64(p)); p+=8;
                v3 = XXH64_round(v3, XXH_readLE64(p)); p+=8;
                v4 = XXH64_round(v4, XXH_readLE64(p)); p+=8;
            } while (p<=limit);

            state->v1 = v1;
            state->v2 = v2;
            state->v3 = v3;
            state->v4 = v4;
        }

        if (p < bEnd) {
            XXH_memcpy(state->mem64, p, (size_t)(bEnd-p));
            state->memsize = (unsigned)(bEnd-p);
        }
    }

    return XXH_OK;
}


XXH_PUBLIC_API XXH64_hash_t XXH64_digest (const XXH64_state_t* state)
{
    xxh_u64 h64;

    if (state->total_len >= 32) {
        xxh_u64 const v1 = state->v1;
        xxh_u64 const v2 = state->v2;
        xxh_u64 const v3 = state->v3;
        xxh_u64 const v4 = state->v4;

        h64 = XXH_rotl64(v1, 1) + XXH_rotl64(v2, 7) + XXH_rotl64(v3, 12) + XXH_rotl64(v4, 18);
        h64 = XXH64_mergeRound(h64, v1);
        h64 = XXH64_mergeRound(h64, v2);
        h64 = XXH64_mergeRound(h64, v3);
        h64 = XXH64_mergeRound(h64, v4);
    } else {
        h64  = state->v3 /*seed*/ + PRIME64_5;
    }

    h64 += (xxh_u64) state->total_len;

    return XXH64_finalize(h64, (const xxh_u8*)state->mem64, (size_t)state->total_len, XXH_aligned);
}


/******* Canonical representation   *******/

XXH_PUBLIC_API void XXH64_canonicalFromHash(XXH64_canonical_t* dst, XXH64_hash_t hash)
{
    XXH_STATIC_ASSERT(sizeof(XXH64_canonical_t) == sizeof(XXH64_hash_t));
    if (XXH_CPU_LITTLE_ENDIAN) hash = XXH_swap64(hash);
    memcpy(dst, &hash, sizeof(*dst));
}

XXH_PUBLIC_API XXH64_hash_t XXH64_hashFromCanonical(const XXH64_canonical_t* src)
{
    return XXH_readBE64(src);
}



/* *********************************************************************
*  XXH3
*  New generation hash designed for speed on small keys and vectorization
************************************************************************ */

/* #include "xxh3.h" */


#endif  /* XXH_NO_LONG_LONG */


#endif  /* XXH_IMPLEMENTATION */


#if defined (__cplusplus)
}
#endif