Current File : //usr/src/linux-headers-5.15.0-125-generic/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>
/*-****************************
* 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.
*/
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.
*/
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 BITS_PER_LONG == 64
return xxh64(input, length, seed);
#else
return xxh32(input, length, seed);
#endif
}
/*-****************************
* 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.
*/
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.
*/
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.
*/
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.
*/
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.
*/
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.
*/
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.
*/
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.
*/
void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src);
#endif /* XXHASH_H */
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