archive.mod/zstd.mod/zstd/contrib/linux-kernel/test/include/linux/xxhash.h

/*
 * xxHash - Extremely 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.
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 2 as published by the
 * Free Software Foundation. This program is dual-licensed; you may select
 * either version 2 of the GNU General Public License ("GPL") or BSD license
 * ("BSD").
 *
 * You can contact the author at:
 * - xxHash homepage: https://cyan4973.github.io/xxHash/
 * - 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.
 *
 * A 64-bits version, named xxh64 offers much better speed,
 * but for 64-bits 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
 */

#ifndef XXHASH_H
#define XXHASH_H

#include <linux/types.h>

#define XXH_API static inline __attribute__((unused))
/*-****************************
 * Simple Hash Functions
 *****************************/

/**
 * xxh32() - calculate the 32-bit hash of the input with a given seed.
 *
 * @input:  The data to hash.
 * @length: The length of the data to hash.
 * @seed:   The seed can be used to alter the result predictably.
 *
 * Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s
 *
 * Return:  The 32-bit hash of the data.
 */
XXH_API uint32_t xxh32(const void *input, size_t length, uint32_t seed);

/**
 * xxh64() - calculate the 64-bit hash of the input with a given seed.
 *
 * @input:  The data to hash.
 * @length: The length of the data to hash.
 * @seed:   The seed can be used to alter the result predictably.
 *
 * This function runs 2x faster on 64-bit systems, but slower on 32-bit systems.
 *
 * Return:  The 64-bit hash of the data.
 */
XXH_API uint64_t xxh64(const void *input, size_t length, uint64_t seed);

/**
 * xxhash() - calculate wordsize hash of the input with a given seed
 * @input:  The data to hash.
 * @length: The length of the data to hash.
 * @seed:   The seed can be used to alter the result predictably.
 *
 * If the hash does not need to be comparable between machines with
 * different word sizes, this function will call whichever of xxh32()
 * or xxh64() is faster.
 *
 * Return:  wordsize hash of the data.
 */

static inline unsigned long xxhash(const void *input, size_t length,
				   uint64_t seed)
{
	if (sizeof(size_t) == 8)
		return xxh64(input, length, seed);
	else
		return xxh32(input, length, seed);
}

/*-****************************
 * Streaming Hash Functions
 *****************************/

/*
 * These definitions are only meant to allow allocation of XXH state
 * statically, on stack, or in a struct for example.
 * Do not use members directly.
 */

/**
 * struct xxh32_state - private xxh32 state, do not use members directly
 */
struct xxh32_state {
	uint32_t total_len_32;
	uint32_t large_len;
	uint32_t v1;
	uint32_t v2;
	uint32_t v3;
	uint32_t v4;
	uint32_t mem32[4];
	uint32_t memsize;
};

/**
 * struct xxh32_state - private xxh64 state, do not use members directly
 */
struct xxh64_state {
	uint64_t total_len;
	uint64_t v1;
	uint64_t v2;
	uint64_t v3;
	uint64_t v4;
	uint64_t mem64[4];
	uint32_t memsize;
};

/**
 * xxh32_reset() - reset the xxh32 state to start a new hashing operation
 *
 * @state: The xxh32 state to reset.
 * @seed:  Initialize the hash state with this seed.
 *
 * Call this function on any xxh32_state to prepare for a new hashing operation.
 */
XXH_API void xxh32_reset(struct xxh32_state *state, uint32_t seed);

/**
 * xxh32_update() - hash the data given and update the xxh32 state
 *
 * @state:  The xxh32 state to update.
 * @input:  The data to hash.
 * @length: The length of the data to hash.
 *
 * After calling xxh32_reset() call xxh32_update() as many times as necessary.
 *
 * Return:  Zero on success, otherwise an error code.
 */
XXH_API int xxh32_update(struct xxh32_state *state, const void *input, size_t length);

/**
 * xxh32_digest() - produce the current xxh32 hash
 *
 * @state: Produce the current xxh32 hash of this state.
 *
 * A hash value can be produced at any time. It is still possible to continue
 * inserting input into the hash state after a call to xxh32_digest(), and
 * generate new hashes later on, by calling xxh32_digest() again.
 *
 * Return: The xxh32 hash stored in the state.
 */
XXH_API uint32_t xxh32_digest(const struct xxh32_state *state);

/**
 * xxh64_reset() - reset the xxh64 state to start a new hashing operation
 *
 * @state: The xxh64 state to reset.
 * @seed:  Initialize the hash state with this seed.
 */
XXH_API void xxh64_reset(struct xxh64_state *state, uint64_t seed);

/**
 * xxh64_update() - hash the data given and update the xxh64 state
 * @state:  The xxh64 state to update.
 * @input:  The data to hash.
 * @length: The length of the data to hash.
 *
 * After calling xxh64_reset() call xxh64_update() as many times as necessary.
 *
 * Return:  Zero on success, otherwise an error code.
 */
XXH_API int xxh64_update(struct xxh64_state *state, const void *input, size_t length);

/**
 * xxh64_digest() - produce the current xxh64 hash
 *
 * @state: Produce the current xxh64 hash of this state.
 *
 * A hash value can be produced at any time. It is still possible to continue
 * inserting input into the hash state after a call to xxh64_digest(), and
 * generate new hashes later on, by calling xxh64_digest() again.
 *
 * Return: The xxh64 hash stored in the state.
 */
XXH_API uint64_t xxh64_digest(const struct xxh64_state *state);

/*-**************************
 * Utils
 ***************************/

/**
 * xxh32_copy_state() - copy the source state into the destination state
 *
 * @src: The source xxh32 state.
 * @dst: The destination xxh32 state.
 */
XXH_API void xxh32_copy_state(struct xxh32_state *dst, const struct xxh32_state *src);

/**
 * xxh64_copy_state() - copy the source state into the destination state
 *
 * @src: The source xxh64 state.
 * @dst: The destination xxh64 state.
 */
XXH_API void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src);

/*
 * xxHash - Extremely 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.
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 2 as published by the
 * Free Software Foundation. This program is dual-licensed; you may select
 * either version 2 of the GNU General Public License ("GPL") or BSD license
 * ("BSD").
 *
 * You can contact the author at:
 * - xxHash homepage: https://cyan4973.github.io/xxHash/
 * - xxHash source repository: https://github.com/Cyan4973/xxHash
 */

#include <asm/unaligned.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/xxhash.h>

/*-*************************************
 * Macros
 **************************************/
#define xxh_rotl32(x, r) ((x << r) | (x >> (32 - r)))
#define xxh_rotl64(x, r) ((x << r) | (x >> (64 - r)))

#ifdef __LITTLE_ENDIAN
# define XXH_CPU_LITTLE_ENDIAN 1
#else
# define XXH_CPU_LITTLE_ENDIAN 0
#endif

/*-*************************************
 * Constants
 **************************************/
static const uint32_t PRIME32_1 = 2654435761U;
static const uint32_t PRIME32_2 = 2246822519U;
static const uint32_t PRIME32_3 = 3266489917U;
static const uint32_t PRIME32_4 =  668265263U;
static const uint32_t PRIME32_5 =  374761393U;

static const uint64_t PRIME64_1 = 11400714785074694791ULL;
static const uint64_t PRIME64_2 = 14029467366897019727ULL;
static const uint64_t PRIME64_3 =  1609587929392839161ULL;
static const uint64_t PRIME64_4 =  9650029242287828579ULL;
static const uint64_t PRIME64_5 =  2870177450012600261ULL;

/*-**************************
 *  Utils
 ***************************/
XXH_API void xxh32_copy_state(struct xxh32_state *dst, const struct xxh32_state *src)
{
	__builtin_memcpy(dst, src, sizeof(*dst));
}

XXH_API void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src)
{
	__builtin_memcpy(dst, src, sizeof(*dst));
}

/*-***************************
 * Simple Hash Functions
 ****************************/
static uint32_t xxh32_round(uint32_t seed, const uint32_t input)
{
	seed += input * PRIME32_2;
	seed = xxh_rotl32(seed, 13);
	seed *= PRIME32_1;
	return seed;
}

XXH_API uint32_t xxh32(const void *input, const size_t len, const uint32_t seed)
{
	const uint8_t *p = (const uint8_t *)input;
	const uint8_t *b_end = p + len;
	uint32_t h32;

	if (len >= 16) {
		const uint8_t *const limit = b_end - 16;
		uint32_t v1 = seed + PRIME32_1 + PRIME32_2;
		uint32_t v2 = seed + PRIME32_2;
		uint32_t v3 = seed + 0;
		uint32_t v4 = seed - PRIME32_1;

		do {
			v1 = xxh32_round(v1, get_unaligned_le32(p));
			p += 4;
			v2 = xxh32_round(v2, get_unaligned_le32(p));
			p += 4;
			v3 = xxh32_round(v3, get_unaligned_le32(p));
			p += 4;
			v4 = xxh32_round(v4, get_unaligned_le32(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 += (uint32_t)len;

	while (p + 4 <= b_end) {
		h32 += get_unaligned_le32(p) * PRIME32_3;
		h32 = xxh_rotl32(h32, 17) * PRIME32_4;
		p += 4;
	}

	while (p < b_end) {
		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;
}

static uint64_t xxh64_round(uint64_t acc, const uint64_t input)
{
	acc += input * PRIME64_2;
	acc = xxh_rotl64(acc, 31);
	acc *= PRIME64_1;
	return acc;
}

static uint64_t xxh64_merge_round(uint64_t acc, uint64_t val)
{
	val = xxh64_round(0, val);
	acc ^= val;
	acc = acc * PRIME64_1 + PRIME64_4;
	return acc;
}

XXH_API uint64_t xxh64(const void *input, const size_t len, const uint64_t seed)
{
	const uint8_t *p = (const uint8_t *)input;
	const uint8_t *const b_end = p + len;
	uint64_t h64;

	if (len >= 32) {
		const uint8_t *const limit = b_end - 32;
		uint64_t v1 = seed + PRIME64_1 + PRIME64_2;
		uint64_t v2 = seed + PRIME64_2;
		uint64_t v3 = seed + 0;
		uint64_t v4 = seed - PRIME64_1;

		do {
			v1 = xxh64_round(v1, get_unaligned_le64(p));
			p += 8;
			v2 = xxh64_round(v2, get_unaligned_le64(p));
			p += 8;
			v3 = xxh64_round(v3, get_unaligned_le64(p));
			p += 8;
			v4 = xxh64_round(v4, get_unaligned_le64(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_merge_round(h64, v1);
		h64 = xxh64_merge_round(h64, v2);
		h64 = xxh64_merge_round(h64, v3);
		h64 = xxh64_merge_round(h64, v4);

	} else {
		h64  = seed + PRIME64_5;
	}

	h64 += (uint64_t)len;

	while (p + 8 <= b_end) {
		const uint64_t k1 = xxh64_round(0, get_unaligned_le64(p));

		h64 ^= k1;
		h64 = xxh_rotl64(h64, 27) * PRIME64_1 + PRIME64_4;
		p += 8;
	}

	if (p + 4 <= b_end) {
		h64 ^= (uint64_t)(get_unaligned_le32(p)) * PRIME64_1;
		h64 = xxh_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
		p += 4;
	}

	while (p < b_end) {
		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;
}

/*-**************************************************
 * Advanced Hash Functions
 ***************************************************/
XXH_API void xxh32_reset(struct xxh32_state *statePtr, const uint32_t seed)
{
	/* use a local state for memcpy() to avoid strict-aliasing warnings */
	struct xxh32_state state;

	__builtin_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;
	__builtin_memcpy(statePtr, &state, sizeof(state));
}

XXH_API void xxh64_reset(struct xxh64_state *statePtr, const uint64_t seed)
{
	/* use a local state for memcpy() to avoid strict-aliasing warnings */
	struct xxh64_state state;

	__builtin_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;
	__builtin_memcpy(statePtr, &state, sizeof(state));
}

XXH_API int xxh32_update(struct xxh32_state *state, const void *input, const size_t len)
{
	const uint8_t *p = (const uint8_t *)input;
	const uint8_t *const b_end = p + len;

	if (input == NULL)
		return -EINVAL;

	state->total_len_32 += (uint32_t)len;
	state->large_len |= (len >= 16) | (state->total_len_32 >= 16);

	if (state->memsize + len < 16) { /* fill in tmp buffer */
		__builtin_memcpy((uint8_t *)(state->mem32) + state->memsize, input, len);
		state->memsize += (uint32_t)len;
		return 0;
	}

	if (state->memsize) { /* some data left from previous update */
		const uint32_t *p32 = state->mem32;

		__builtin_memcpy((uint8_t *)(state->mem32) + state->memsize, input,
			16 - state->memsize);

		state->v1 = xxh32_round(state->v1, get_unaligned_le32(p32));
		p32++;
		state->v2 = xxh32_round(state->v2, get_unaligned_le32(p32));
		p32++;
		state->v3 = xxh32_round(state->v3, get_unaligned_le32(p32));
		p32++;
		state->v4 = xxh32_round(state->v4, get_unaligned_le32(p32));
		p32++;

		p += 16-state->memsize;
		state->memsize = 0;
	}

	if (p <= b_end - 16) {
		const uint8_t *const limit = b_end - 16;
		uint32_t v1 = state->v1;
		uint32_t v2 = state->v2;
		uint32_t v3 = state->v3;
		uint32_t v4 = state->v4;

		do {
			v1 = xxh32_round(v1, get_unaligned_le32(p));
			p += 4;
			v2 = xxh32_round(v2, get_unaligned_le32(p));
			p += 4;
			v3 = xxh32_round(v3, get_unaligned_le32(p));
			p += 4;
			v4 = xxh32_round(v4, get_unaligned_le32(p));
			p += 4;
		} while (p <= limit);

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

	if (p < b_end) {
		__builtin_memcpy(state->mem32, p, (size_t)(b_end-p));
		state->memsize = (uint32_t)(b_end-p);
	}

	return 0;
}

XXH_API uint32_t xxh32_digest(const struct xxh32_state *state)
{
	const uint8_t *p = (const uint8_t *)state->mem32;
	const uint8_t *const b_end = (const uint8_t *)(state->mem32) +
		state->memsize;
	uint32_t 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 <= b_end) {
		h32 += get_unaligned_le32(p) * PRIME32_3;
		h32 = xxh_rotl32(h32, 17) * PRIME32_4;
		p += 4;
	}

	while (p < b_end) {
		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_API int xxh64_update(struct xxh64_state *state, const void *input, const size_t len)
{
	const uint8_t *p = (const uint8_t *)input;
	const uint8_t *const b_end = p + len;

	if (input == NULL)
		return -EINVAL;

	state->total_len += len;

	if (state->memsize + len < 32) { /* fill in tmp buffer */
		__builtin_memcpy(((uint8_t *)state->mem64) + state->memsize, input, len);
		state->memsize += (uint32_t)len;
		return 0;
	}

	if (state->memsize) { /* tmp buffer is full */
		uint64_t *p64 = state->mem64;

		__builtin_memcpy(((uint8_t *)p64) + state->memsize, input,
			32 - state->memsize);

		state->v1 = xxh64_round(state->v1, get_unaligned_le64(p64));
		p64++;
		state->v2 = xxh64_round(state->v2, get_unaligned_le64(p64));
		p64++;
		state->v3 = xxh64_round(state->v3, get_unaligned_le64(p64));
		p64++;
		state->v4 = xxh64_round(state->v4, get_unaligned_le64(p64));

		p += 32 - state->memsize;
		state->memsize = 0;
	}

	if (p + 32 <= b_end) {
		const uint8_t *const limit = b_end - 32;
		uint64_t v1 = state->v1;
		uint64_t v2 = state->v2;
		uint64_t v3 = state->v3;
		uint64_t v4 = state->v4;

		do {
			v1 = xxh64_round(v1, get_unaligned_le64(p));
			p += 8;
			v2 = xxh64_round(v2, get_unaligned_le64(p));
			p += 8;
			v3 = xxh64_round(v3, get_unaligned_le64(p));
			p += 8;
			v4 = xxh64_round(v4, get_unaligned_le64(p));
			p += 8;
		} while (p <= limit);

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

	if (p < b_end) {
		__builtin_memcpy(state->mem64, p, (size_t)(b_end-p));
		state->memsize = (uint32_t)(b_end - p);
	}

	return 0;
}

XXH_API uint64_t xxh64_digest(const struct xxh64_state *state)
{
	const uint8_t *p = (const uint8_t *)state->mem64;
	const uint8_t *const b_end = (const uint8_t *)state->mem64 +
		state->memsize;
	uint64_t h64;

	if (state->total_len >= 32) {
		const uint64_t v1 = state->v1;
		const uint64_t v2 = state->v2;
		const uint64_t v3 = state->v3;
		const uint64_t v4 = state->v4;

		h64 = xxh_rotl64(v1, 1) + xxh_rotl64(v2, 7) +
			xxh_rotl64(v3, 12) + xxh_rotl64(v4, 18);
		h64 = xxh64_merge_round(h64, v1);
		h64 = xxh64_merge_round(h64, v2);
		h64 = xxh64_merge_round(h64, v3);
		h64 = xxh64_merge_round(h64, v4);
	} else {
		h64  = state->v3 + PRIME64_5;
	}

	h64 += (uint64_t)state->total_len;

	while (p + 8 <= b_end) {
		const uint64_t k1 = xxh64_round(0, get_unaligned_le64(p));

		h64 ^= k1;
		h64 = xxh_rotl64(h64, 27) * PRIME64_1 + PRIME64_4;
		p += 8;
	}

	if (p + 4 <= b_end) {
		h64 ^= (uint64_t)(get_unaligned_le32(p)) * PRIME64_1;
		h64 = xxh_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
		p += 4;
	}

	while (p < b_end) {
		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;
}

#endif /* XXHASH_H */