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1/*
2 * xxHash - Extremely Fast Hash algorithm
3 * Copyright (C) 2012-2016, Yann Collet.
4 *
5 * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are
9 * met:
10 *
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * * Redistributions in binary form must reproduce the above
14 * copyright notice, this list of conditions and the following disclaimer
15 * in the documentation and/or other materials provided with the
16 * distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * This program is free software; you can redistribute it and/or modify it under
31 * the terms of the GNU General Public License version 2 as published by the
32 * Free Software Foundation. This program is dual-licensed; you may select
33 * either version 2 of the GNU General Public License ("GPL") or BSD license
34 * ("BSD").
35 *
36 * You can contact the author at:
37 * - xxHash homepage: https://cyan4973.github.io/xxHash/
38 * - xxHash source repository: https://github.com/Cyan4973/xxHash
39 */
40
41/*
42 * Notice extracted from xxHash homepage:
43 *
44 * xxHash is an extremely fast Hash algorithm, running at RAM speed limits.
45 * It also successfully passes all tests from the SMHasher suite.
46 *
47 * Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2
48 * Duo @3GHz)
49 *
50 * Name Speed Q.Score Author
51 * xxHash 5.4 GB/s 10
52 * CrapWow 3.2 GB/s 2 Andrew
53 * MumurHash 3a 2.7 GB/s 10 Austin Appleby
54 * SpookyHash 2.0 GB/s 10 Bob Jenkins
55 * SBox 1.4 GB/s 9 Bret Mulvey
56 * Lookup3 1.2 GB/s 9 Bob Jenkins
57 * SuperFastHash 1.2 GB/s 1 Paul Hsieh
58 * CityHash64 1.05 GB/s 10 Pike & Alakuijala
59 * FNV 0.55 GB/s 5 Fowler, Noll, Vo
60 * CRC32 0.43 GB/s 9
61 * MD5-32 0.33 GB/s 10 Ronald L. Rivest
62 * SHA1-32 0.28 GB/s 10
63 *
64 * Q.Score is a measure of quality of the hash function.
65 * It depends on successfully passing SMHasher test set.
66 * 10 is a perfect score.
67 *
68 * A 64-bits version, named xxh64 offers much better speed,
69 * but for 64-bits applications only.
70 * Name Speed on 64 bits Speed on 32 bits
71 * xxh64 13.8 GB/s 1.9 GB/s
72 * xxh32 6.8 GB/s 6.0 GB/s
73 */
74
75#ifndef XXHASH_H
76#define XXHASH_H
77
78#include <linux/types.h>
79
80/*-****************************
81 * Simple Hash Functions
82 *****************************/
83
84/**
85 * xxh32() - calculate the 32-bit hash of the input with a given seed.
86 *
87 * @input: The data to hash.
88 * @length: The length of the data to hash.
89 * @seed: The seed can be used to alter the result predictably.
90 *
91 * Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s
92 *
93 * Return: The 32-bit hash of the data.
94 */
95uint32_t xxh32(const void *input, size_t length, uint32_t seed);
96
97/**
98 * xxh64() - calculate the 64-bit hash of the input with a given seed.
99 *
100 * @input: The data to hash.
101 * @length: The length of the data to hash.
102 * @seed: The seed can be used to alter the result predictably.
103 *
104 * This function runs 2x faster on 64-bit systems, but slower on 32-bit systems.
105 *
106 * Return: The 64-bit hash of the data.
107 */
108uint64_t xxh64(const void *input, size_t length, uint64_t seed);
109
110/**
111 * xxhash() - calculate wordsize hash of the input with a given seed
112 * @input: The data to hash.
113 * @length: The length of the data to hash.
114 * @seed: The seed can be used to alter the result predictably.
115 *
116 * If the hash does not need to be comparable between machines with
117 * different word sizes, this function will call whichever of xxh32()
118 * or xxh64() is faster.
119 *
120 * Return: wordsize hash of the data.
121 */
122
123static inline unsigned long xxhash(const void *input, size_t length,
124 uint64_t seed)
125{
126#if BITS_PER_LONG == 64
127 return xxh64(input, length, seed);
128#else
129 return xxh32(input, length, seed);
130#endif
131}
132
133/*-****************************
134 * Streaming Hash Functions
135 *****************************/
136
137/*
138 * These definitions are only meant to allow allocation of XXH state
139 * statically, on stack, or in a struct for example.
140 * Do not use members directly.
141 */
142
143/**
144 * struct xxh64_state - private xxh64 state, do not use members directly
145 */
146struct xxh64_state {
147 uint64_t total_len;
148 uint64_t v1;
149 uint64_t v2;
150 uint64_t v3;
151 uint64_t v4;
152 uint64_t mem64[4];
153 uint32_t memsize;
154};
155
156/**
157 * xxh64_reset() - reset the xxh64 state to start a new hashing operation
158 *
159 * @state: The xxh64 state to reset.
160 * @seed: Initialize the hash state with this seed.
161 */
162void xxh64_reset(struct xxh64_state *state, uint64_t seed);
163
164/**
165 * xxh64_update() - hash the data given and update the xxh64 state
166 * @state: The xxh64 state to update.
167 * @input: The data to hash.
168 * @length: The length of the data to hash.
169 *
170 * After calling xxh64_reset() call xxh64_update() as many times as necessary.
171 *
172 * Return: Zero on success, otherwise an error code.
173 */
174int xxh64_update(struct xxh64_state *state, const void *input, size_t length);
175
176/**
177 * xxh64_digest() - produce the current xxh64 hash
178 *
179 * @state: Produce the current xxh64 hash of this state.
180 *
181 * A hash value can be produced at any time. It is still possible to continue
182 * inserting input into the hash state after a call to xxh64_digest(), and
183 * generate new hashes later on, by calling xxh64_digest() again.
184 *
185 * Return: The xxh64 hash stored in the state.
186 */
187uint64_t xxh64_digest(const struct xxh64_state *state);
188
189#endif /* XXHASH_H */