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