contrib/python-zstandard/zstd/common/xxhash.c

dirstate-v2: freeze the on-disk format

It seems the format as reached a good balance. With a core of new capabilities
that motivated it initially and enough new feature and room for future
improvement to be a clear progress we can set a milestone for.

Having the format frozen will help the feature to get real life testing, outside
of the test suite.

The feature itself stay experimental but the config gains a new name to avoid
people enable non-frozen version by default.

If too many bugs are reported during the RC we might move the format back to
experimental and drop its support in future version (in favor of a new one)

Differential Revision: https://phab.mercurial-scm.org/D11709

/*
*  xxHash - Fast Hash algorithm
*  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 homepage: http://www.xxhash.com
*  - xxHash source repository : https://github.com/Cyan4973/xxHash
*/


/* *************************************
*  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(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
#    define XXH_FORCE_MEMORY_ACCESS 2
#  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
  (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) )) || \
  defined(__ICCARM__)
#    define XXH_FORCE_MEMORY_ACCESS 1
#  endif
#endif

/*!XXH_ACCEPT_NULL_INPUT_POINTER :
 * If the input pointer is a null pointer, xxHash default behavior is to trigger a memory access error, since it is a bad pointer.
 * When this option is enabled, xxHash output for null input pointers will be the same as a null-length input.
 * By default, this option is disabled. To enable it, uncomment below define :
 */
/* #define XXH_ACCEPT_NULL_INPUT_POINTER 1 */

/*!XXH_FORCE_NATIVE_FORMAT :
 * By default, xxHash library provides endian-independent Hash values, based on little-endian convention.
 * Results are therefore identical for little-endian and big-endian CPU.
 * This comes at a performance cost for big-endian CPU, since some swapping is required to emulate little-endian format.
 * Should endian-independence be of no importance for your application, you may set the #define below to 1,
 * to improve speed for Big-endian CPU.
 * This option has no impact on Little_Endian CPU.
 */
#ifndef XXH_FORCE_NATIVE_FORMAT   /* can be defined externally */
#  define XXH_FORCE_NATIVE_FORMAT 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 to 0 when the input data
 * is guaranteed to be aligned.
 */
#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


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

#ifndef XXH_STATIC_LINKING_ONLY
#  define XXH_STATIC_LINKING_ONLY
#endif
#include "xxhash.h"


/* *************************************
*  Compiler Specific Options
***************************************/
#if defined (__GNUC__) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
#  define INLINE_KEYWORD inline
#else
#  define INLINE_KEYWORD
#endif

#if defined(__GNUC__) || defined(__ICCARM__)
#  define FORCE_INLINE_ATTR __attribute__((always_inline))
#elif defined(_MSC_VER)
#  define FORCE_INLINE_ATTR __forceinline
#else
#  define FORCE_INLINE_ATTR
#endif

#define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR


#ifdef _MSC_VER
#  pragma warning(disable : 4127)      /* disable: C4127: conditional expression is constant */
#endif


/* *************************************
*  Basic Types
***************************************/
#ifndef MEM_MODULE
# define MEM_MODULE
# if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
#   include <stdint.h>
    typedef uint8_t  BYTE;
    typedef uint16_t U16;
    typedef uint32_t U32;
    typedef  int32_t S32;
    typedef uint64_t U64;
#  else
    typedef unsigned char      BYTE;
    typedef unsigned short     U16;
    typedef unsigned int       U32;
    typedef   signed int       S32;
    typedef unsigned long long U64;   /* if your compiler doesn't support unsigned long long, replace by another 64-bit type here. Note that xxhash.h will also need to be updated. */
#  endif
#endif


#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 U32 XXH_read32(const void* memPtr) { return *(const U32*) memPtr; }
static U64 XXH_read64(const void* memPtr) { return *(const 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 { U32 u32; U64 u64; } __attribute__((packed)) unalign;

static U32 XXH_read32(const void* ptr) { return ((const unalign*)ptr)->u32; }
static U64 XXH_read64(const void* ptr) { return ((const unalign*)ptr)->u64; }

#else

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

static U32 XXH_read32(const void* memPtr)
{
    U32 val;
    memcpy(&val, memPtr, sizeof(val));
    return val;
}

static U64 XXH_read64(const void* memPtr)
{
    U64 val;
    memcpy(&val, memPtr, sizeof(val));
    return val;
}

#endif   /* XXH_FORCE_DIRECT_MEMORY_ACCESS */


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

/* Note : although _rotl exists for minGW (GCC under windows), performance seems poor */
#if defined(_MSC_VER)
#  define XXH_rotl32(x,r) _rotl(x,r)
#  define XXH_rotl64(x,r) _rotl64(x,r)
#else
#if defined(__ICCARM__)
#  include <intrinsics.h>
#  define XXH_rotl32(x,r) __ROR(x,(32 - r))
#else
#  define XXH_rotl32(x,r) ((x << r) | (x >> (32 - r)))
#endif
#  define XXH_rotl64(x,r) ((x << r) | (x >> (64 - r)))
#endif

#if defined(_MSC_VER)     /* Visual Studio */
#  define XXH_swap32 _byteswap_ulong
#  define XXH_swap64 _byteswap_uint64
#elif GCC_VERSION >= 403
#  define XXH_swap32 __builtin_bswap32
#  define XXH_swap64 __builtin_bswap64
#else
static U32 XXH_swap32 (U32 x)
{
    return  ((x << 24) & 0xff000000 ) |
            ((x <<  8) & 0x00ff0000 ) |
            ((x >>  8) & 0x0000ff00 ) |
            ((x >> 24) & 0x000000ff );
}
static U64 XXH_swap64 (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


/* *************************************
*  Architecture Macros
***************************************/
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
    static const int g_one = 1;
#   define XXH_CPU_LITTLE_ENDIAN   (*(const char*)(&g_one))
#endif


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

FORCE_INLINE_TEMPLATE U32 XXH_readLE32_align(const void* ptr, XXH_endianess endian, XXH_alignment align)
{
    if (align==XXH_unaligned)
        return endian==XXH_littleEndian ? XXH_read32(ptr) : XXH_swap32(XXH_read32(ptr));
    else
        return endian==XXH_littleEndian ? *(const U32*)ptr : XXH_swap32(*(const U32*)ptr);
}

FORCE_INLINE_TEMPLATE U32 XXH_readLE32(const void* ptr, XXH_endianess endian)
{
    return XXH_readLE32_align(ptr, endian, XXH_unaligned);
}

static U32 XXH_readBE32(const void* ptr)
{
    return XXH_CPU_LITTLE_ENDIAN ? XXH_swap32(XXH_read32(ptr)) : XXH_read32(ptr);
}

FORCE_INLINE_TEMPLATE U64 XXH_readLE64_align(const void* ptr, XXH_endianess endian, XXH_alignment align)
{
    if (align==XXH_unaligned)
        return endian==XXH_littleEndian ? XXH_read64(ptr) : XXH_swap64(XXH_read64(ptr));
    else
        return endian==XXH_littleEndian ? *(const U64*)ptr : XXH_swap64(*(const U64*)ptr);
}

FORCE_INLINE_TEMPLATE U64 XXH_readLE64(const void* ptr, XXH_endianess endian)
{
    return XXH_readLE64_align(ptr, endian, XXH_unaligned);
}

static U64 XXH_readBE64(const void* ptr)
{
    return XXH_CPU_LITTLE_ENDIAN ? XXH_swap64(XXH_read64(ptr)) : XXH_read64(ptr);
}


/* *************************************
*  Macros
***************************************/
#define XXH_STATIC_ASSERT(c)   { enum { XXH_static_assert = 1/(int)(!!(c)) }; }    /* use only *after* variable declarations */


/* *************************************
*  Constants
***************************************/
static const U32 PRIME32_1 = 2654435761U;
static const U32 PRIME32_2 = 2246822519U;
static const U32 PRIME32_3 = 3266489917U;
static const U32 PRIME32_4 =  668265263U;
static const U32 PRIME32_5 =  374761393U;

static const U64 PRIME64_1 = 11400714785074694791ULL;
static const U64 PRIME64_2 = 14029467366897019727ULL;
static const U64 PRIME64_3 =  1609587929392839161ULL;
static const U64 PRIME64_4 =  9650029242287828579ULL;
static const U64 PRIME64_5 =  2870177450012600261ULL;

XXH_PUBLIC_API unsigned XXH_versionNumber (void) { return XXH_VERSION_NUMBER; }


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

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


/* ***************************
*  Simple Hash Functions
*****************************/

static U32 XXH32_round(U32 seed, U32 input)
{
    seed += input * PRIME32_2;
    seed  = XXH_rotl32(seed, 13);
    seed *= PRIME32_1;
    return seed;
}

FORCE_INLINE_TEMPLATE U32 XXH32_endian_align(const void* input, size_t len, U32 seed, XXH_endianess endian, XXH_alignment align)
{
    const BYTE* p = (const BYTE*)input;
    const BYTE* bEnd = p + len;
    U32 h32;
#define XXH_get32bits(p) XXH_readLE32_align(p, endian, align)

#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
    if (p==NULL) {
        len=0;
        bEnd=p=(const BYTE*)(size_t)16;
    }
#endif

    if (len>=16) {
        const BYTE* const limit = bEnd - 16;
        U32 v1 = seed + PRIME32_1 + PRIME32_2;
        U32 v2 = seed + PRIME32_2;
        U32 v3 = seed + 0;
        U32 v4 = seed - PRIME32_1;

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

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

    h32 += (U32) len;

    while (p+4<=bEnd) {
        h32 += XXH_get32bits(p) * PRIME32_3;
        h32  = XXH_rotl32(h32, 17) * PRIME32_4 ;
        p+=4;
    }

    while (p<bEnd) {
        h32 += (*p) * PRIME32_5;
        h32 = XXH_rotl32(h32, 11) * PRIME32_1 ;
        p++;
    }

    h32 ^= h32 >> 15;
    h32 *= PRIME32_2;
    h32 ^= h32 >> 13;
    h32 *= PRIME32_3;
    h32 ^= h32 >> 16;

    return h32;
}


XXH_PUBLIC_API unsigned int XXH32 (const void* input, size_t len, unsigned int seed)
{
#if 0
    /* Simple version, good for code maintenance, but unfortunately slow for small inputs */
    XXH32_CREATESTATE_STATIC(state);
    XXH32_reset(state, seed);
    XXH32_update(state, input, len);
    return XXH32_digest(state);
#else
    XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;

    if (XXH_FORCE_ALIGN_CHECK) {
        if ((((size_t)input) & 3) == 0) {   /* Input is 4-bytes aligned, leverage the speed benefit */
            if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
                return XXH32_endian_align(input, len, seed, XXH_littleEndian, XXH_aligned);
            else
                return XXH32_endian_align(input, len, seed, XXH_bigEndian, XXH_aligned);
    }   }

    if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
        return XXH32_endian_align(input, len, seed, XXH_littleEndian, XXH_unaligned);
    else
        return XXH32_endian_align(input, len, seed, XXH_bigEndian, XXH_unaligned);
#endif
}


static U64 XXH64_round(U64 acc, U64 input)
{
    acc += input * PRIME64_2;
    acc  = XXH_rotl64(acc, 31);
    acc *= PRIME64_1;
    return acc;
}

static U64 XXH64_mergeRound(U64 acc, U64 val)
{
    val  = XXH64_round(0, val);
    acc ^= val;
    acc  = acc * PRIME64_1 + PRIME64_4;
    return acc;
}

FORCE_INLINE_TEMPLATE U64 XXH64_endian_align(const void* input, size_t len, U64 seed, XXH_endianess endian, XXH_alignment align)
{
    const BYTE* p = (const BYTE*)input;
    const BYTE* const bEnd = p + len;
    U64 h64;
#define XXH_get64bits(p) XXH_readLE64_align(p, endian, align)

#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
    if (p==NULL) {
        len=0;
        bEnd=p=(const BYTE*)(size_t)32;
    }
#endif

    if (len>=32) {
        const BYTE* const limit = bEnd - 32;
        U64 v1 = seed + PRIME64_1 + PRIME64_2;
        U64 v2 = seed + PRIME64_2;
        U64 v3 = seed + 0;
        U64 v4 = seed - PRIME64_1;

        do {
            v1 = XXH64_round(v1, XXH_get64bits(p)); p+=8;
            v2 = XXH64_round(v2, XXH_get64bits(p)); p+=8;
            v3 = XXH64_round(v3, XXH_get64bits(p)); p+=8;
            v4 = XXH64_round(v4, XXH_get64bits(p)); p+=8;
        } while (p<=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 += (U64) len;

    while (p+8<=bEnd) {
        U64 const k1 = XXH64_round(0, XXH_get64bits(p));
        h64 ^= k1;
        h64  = XXH_rotl64(h64,27) * PRIME64_1 + PRIME64_4;
        p+=8;
    }

    if (p+4<=bEnd) {
        h64 ^= (U64)(XXH_get32bits(p)) * PRIME64_1;
        h64 = XXH_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
        p+=4;
    }

    while (p<bEnd) {
        h64 ^= (*p) * PRIME64_5;
        h64 = XXH_rotl64(h64, 11) * PRIME64_1;
        p++;
    }

    h64 ^= h64 >> 33;
    h64 *= PRIME64_2;
    h64 ^= h64 >> 29;
    h64 *= PRIME64_3;
    h64 ^= h64 >> 32;

    return h64;
}


XXH_PUBLIC_API unsigned long long XXH64 (const void* input, size_t len, unsigned long long seed)
{
#if 0
    /* Simple version, good for code maintenance, but unfortunately slow for small inputs */
    XXH64_CREATESTATE_STATIC(state);
    XXH64_reset(state, seed);
    XXH64_update(state, input, len);
    return XXH64_digest(state);
#else
    XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;

    if (XXH_FORCE_ALIGN_CHECK) {
        if ((((size_t)input) & 7)==0) {  /* Input is aligned, let's leverage the speed advantage */
            if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
                return XXH64_endian_align(input, len, seed, XXH_littleEndian, XXH_aligned);
            else
                return XXH64_endian_align(input, len, seed, XXH_bigEndian, XXH_aligned);
    }   }

    if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
        return XXH64_endian_align(input, len, seed, XXH_littleEndian, XXH_unaligned);
    else
        return XXH64_endian_align(input, len, seed, XXH_bigEndian, XXH_unaligned);
#endif
}


/* **************************************************
*  Advanced Hash Functions
****************************************************/

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 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;
}


/*** Hash feed ***/

XXH_PUBLIC_API XXH_errorcode XXH32_reset(XXH32_state_t* statePtr, unsigned int seed)
{
    XXH32_state_t state;   /* using a local state to memcpy() in order to avoid strict-aliasing warnings */
    memset(&state, 0, sizeof(state)-4);   /* do not write into reserved, for future removal */
    state.v1 = seed + PRIME32_1 + PRIME32_2;
    state.v2 = seed + PRIME32_2;
    state.v3 = seed + 0;
    state.v4 = seed - PRIME32_1;
    memcpy(statePtr, &state, sizeof(state));
    return XXH_OK;
}


XXH_PUBLIC_API XXH_errorcode XXH64_reset(XXH64_state_t* statePtr, unsigned long long seed)
{
    XXH64_state_t state;   /* using a local state to memcpy() in order to avoid strict-aliasing warnings */
    memset(&state, 0, sizeof(state)-8);   /* do not write into reserved, for future removal */
    state.v1 = seed + PRIME64_1 + PRIME64_2;
    state.v2 = seed + PRIME64_2;
    state.v3 = seed + 0;
    state.v4 = seed - PRIME64_1;
    memcpy(statePtr, &state, sizeof(state));
    return XXH_OK;
}


FORCE_INLINE_TEMPLATE XXH_errorcode XXH32_update_endian (XXH32_state_t* state, const void* input, size_t len, XXH_endianess endian)
{
    const BYTE* p = (const BYTE*)input;
    const BYTE* const bEnd = p + len;

#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
    if (input==NULL) return XXH_ERROR;
#endif

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

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

    if (state->memsize) {   /* some data left from previous update */
        XXH_memcpy((BYTE*)(state->mem32) + state->memsize, input, 16-state->memsize);
        {   const U32* p32 = state->mem32;
            state->v1 = XXH32_round(state->v1, XXH_readLE32(p32, endian)); p32++;
            state->v2 = XXH32_round(state->v2, XXH_readLE32(p32, endian)); p32++;
            state->v3 = XXH32_round(state->v3, XXH_readLE32(p32, endian)); p32++;
            state->v4 = XXH32_round(state->v4, XXH_readLE32(p32, endian)); p32++;
        }
        p += 16-state->memsize;
        state->memsize = 0;
    }

    if (p <= bEnd-16) {
        const BYTE* const limit = bEnd - 16;
        U32 v1 = state->v1;
        U32 v2 = state->v2;
        U32 v3 = state->v3;
        U32 v4 = state->v4;

        do {
            v1 = XXH32_round(v1, XXH_readLE32(p, endian)); p+=4;
            v2 = XXH32_round(v2, XXH_readLE32(p, endian)); p+=4;
            v3 = XXH32_round(v3, XXH_readLE32(p, endian)); p+=4;
            v4 = XXH32_round(v4, XXH_readLE32(p, endian)); 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 XXH_errorcode XXH32_update (XXH32_state_t* state_in, const void* input, size_t len)
{
    XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;

    if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
        return XXH32_update_endian(state_in, input, len, XXH_littleEndian);
    else
        return XXH32_update_endian(state_in, input, len, XXH_bigEndian);
}



FORCE_INLINE_TEMPLATE U32 XXH32_digest_endian (const XXH32_state_t* state, XXH_endianess endian)
{
    const BYTE * p = (const BYTE*)state->mem32;
    const BYTE* const bEnd = (const BYTE*)(state->mem32) + state->memsize;
    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;

    while (p+4<=bEnd) {
        h32 += XXH_readLE32(p, endian) * PRIME32_3;
        h32  = XXH_rotl32(h32, 17) * PRIME32_4;
        p+=4;
    }

    while (p<bEnd) {
        h32 += (*p) * PRIME32_5;
        h32  = XXH_rotl32(h32, 11) * PRIME32_1;
        p++;
    }

    h32 ^= h32 >> 15;
    h32 *= PRIME32_2;
    h32 ^= h32 >> 13;
    h32 *= PRIME32_3;
    h32 ^= h32 >> 16;

    return h32;
}


XXH_PUBLIC_API unsigned int XXH32_digest (const XXH32_state_t* state_in)
{
    XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;

    if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
        return XXH32_digest_endian(state_in, XXH_littleEndian);
    else
        return XXH32_digest_endian(state_in, XXH_bigEndian);
}



/* **** XXH64 **** */

FORCE_INLINE_TEMPLATE XXH_errorcode XXH64_update_endian (XXH64_state_t* state, const void* input, size_t len, XXH_endianess endian)
{
    const BYTE* p = (const BYTE*)input;
    const BYTE* const bEnd = p + len;

#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
    if (input==NULL) return XXH_ERROR;
#endif

    state->total_len += len;

    if (state->memsize + len < 32) {  /* fill in tmp buffer */
        XXH_memcpy(((BYTE*)state->mem64) + state->memsize, input, len);
        state->memsize += (U32)len;
        return XXH_OK;
    }

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

    if (p+32 <= bEnd) {
        const BYTE* const limit = bEnd - 32;
        U64 v1 = state->v1;
        U64 v2 = state->v2;
        U64 v3 = state->v3;
        U64 v4 = state->v4;

        do {
            v1 = XXH64_round(v1, XXH_readLE64(p, endian)); p+=8;
            v2 = XXH64_round(v2, XXH_readLE64(p, endian)); p+=8;
            v3 = XXH64_round(v3, XXH_readLE64(p, endian)); p+=8;
            v4 = XXH64_round(v4, XXH_readLE64(p, endian)); 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 XXH_errorcode XXH64_update (XXH64_state_t* state_in, const void* input, size_t len)
{
    XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;

    if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
        return XXH64_update_endian(state_in, input, len, XXH_littleEndian);
    else
        return XXH64_update_endian(state_in, input, len, XXH_bigEndian);
}



FORCE_INLINE_TEMPLATE U64 XXH64_digest_endian (const XXH64_state_t* state, XXH_endianess endian)
{
    const BYTE * p = (const BYTE*)state->mem64;
    const BYTE* const bEnd = (const BYTE*)state->mem64 + state->memsize;
    U64 h64;

    if (state->total_len >= 32) {
        U64 const v1 = state->v1;
        U64 const v2 = state->v2;
        U64 const v3 = state->v3;
        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 + PRIME64_5;
    }

    h64 += (U64) state->total_len;

    while (p+8<=bEnd) {
        U64 const k1 = XXH64_round(0, XXH_readLE64(p, endian));
        h64 ^= k1;
        h64  = XXH_rotl64(h64,27) * PRIME64_1 + PRIME64_4;
        p+=8;
    }

    if (p+4<=bEnd) {
        h64 ^= (U64)(XXH_readLE32(p, endian)) * PRIME64_1;
        h64  = XXH_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
        p+=4;
    }

    while (p<bEnd) {
        h64 ^= (*p) * PRIME64_5;
        h64  = XXH_rotl64(h64, 11) * PRIME64_1;
        p++;
    }

    h64 ^= h64 >> 33;
    h64 *= PRIME64_2;
    h64 ^= h64 >> 29;
    h64 *= PRIME64_3;
    h64 ^= h64 >> 32;

    return h64;
}


XXH_PUBLIC_API unsigned long long XXH64_digest (const XXH64_state_t* state_in)
{
    XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;

    if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
        return XXH64_digest_endian(state_in, XXH_littleEndian);
    else
        return XXH64_digest_endian(state_in, XXH_bigEndian);
}


/* **************************
*  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, and remain comparable across different systems and programs.
*/

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

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