1 /* SPDX-License-Identifier: (GPL-2.0 or BSD-2-Clause) */
2 /*
3 * xxHash - Extremely Fast Hash algorithm
4 * Copyright (C) 2012-2016, Yann Collet.
5 *
6 * You can contact the author at:
7 * - xxHash homepage: http://cyan4973.github.io/xxHash/
8 * - xxHash source repository: https://github.com/Cyan4973/xxHash
9 */
10
11 /*
12 * Notice extracted from xxHash homepage:
13 *
14 * xxHash is an extremely fast Hash algorithm, running at RAM speed limits.
15 * It also successfully passes all tests from the SMHasher suite.
16 *
17 * Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2
18 * Duo @3GHz)
19 *
20 * Name Speed Q.Score Author
21 * xxHash 5.4 GB/s 10
22 * CrapWow 3.2 GB/s 2 Andrew
23 * MumurHash 3a 2.7 GB/s 10 Austin Appleby
24 * SpookyHash 2.0 GB/s 10 Bob Jenkins
25 * SBox 1.4 GB/s 9 Bret Mulvey
26 * Lookup3 1.2 GB/s 9 Bob Jenkins
27 * SuperFastHash 1.2 GB/s 1 Paul Hsieh
28 * CityHash64 1.05 GB/s 10 Pike & Alakuijala
29 * FNV 0.55 GB/s 5 Fowler, Noll, Vo
30 * CRC32 0.43 GB/s 9
31 * MD5-32 0.33 GB/s 10 Ronald L. Rivest
32 * SHA1-32 0.28 GB/s 10
33 *
34 * Q.Score is a measure of quality of the hash function.
35 * It depends on successfully passing SMHasher test set.
36 * 10 is a perfect score.
37 *
38 * A 64-bits version, named xxh64 offers much better speed,
39 * but for 64-bits applications only.
40 * Name Speed on 64 bits Speed on 32 bits
41 * xxh64 13.8 GB/s 1.9 GB/s
42 * xxh32 6.8 GB/s 6.0 GB/s
43 */
44
45 #ifndef XXHASH_H
46 #define XXHASH_H
47
48 #include <linux/types.h>
49
50 /*-****************************
51 * Simple Hash Functions
52 *****************************/
53
54 /**
55 * xxh32() - calculate the 32-bit hash of the input with a given seed.
56 *
57 * @input: The data to hash.
58 * @length: The length of the data to hash.
59 * @seed: The seed can be used to alter the result predictably.
60 *
61 * Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s
62 *
63 * Return: The 32-bit hash of the data.
64 */
65 uint32_t xxh32(const void *input, size_t length, uint32_t seed);
66
67 /**
68 * xxh64() - calculate the 64-bit hash of the input with a given seed.
69 *
70 * @input: The data to hash.
71 * @length: The length of the data to hash.
72 * @seed: The seed can be used to alter the result predictably.
73 *
74 * This function runs 2x faster on 64-bit systems, but slower on 32-bit systems.
75 *
76 * Return: The 64-bit hash of the data.
77 */
78 uint64_t xxh64(const void *input, size_t length, uint64_t seed);
79
80 /**
81 * xxhash() - calculate wordsize hash of the input with a given seed
82 * @input: The data to hash.
83 * @length: The length of the data to hash.
84 * @seed: The seed can be used to alter the result predictably.
85 *
86 * If the hash does not need to be comparable between machines with
87 * different word sizes, this function will call whichever of xxh32()
88 * or xxh64() is faster.
89 *
90 * Return: wordsize hash of the data.
91 */
92
xxhash(const void * input,size_t length,uint64_t seed)93 static inline unsigned long xxhash(const void *input, size_t length,
94 uint64_t seed)
95 {
96 #if BITS_PER_LONG == 64
97 return xxh64(input, length, seed);
98 #else
99 return xxh32(input, length, seed);
100 #endif
101 }
102
103 /*-****************************
104 * Streaming Hash Functions
105 *****************************/
106
107 /*
108 * These definitions are only meant to allow allocation of XXH state
109 * statically, on stack, or in a struct for example.
110 * Do not use members directly.
111 */
112
113 /**
114 * struct xxh32_state - private xxh32 state, do not use members directly
115 */
116 struct xxh32_state {
117 uint32_t total_len_32;
118 uint32_t large_len;
119 uint32_t v1;
120 uint32_t v2;
121 uint32_t v3;
122 uint32_t v4;
123 uint32_t mem32[4];
124 uint32_t memsize;
125 };
126
127 /**
128 * struct xxh32_state - private xxh64 state, do not use members directly
129 */
130 struct xxh64_state {
131 uint64_t total_len;
132 uint64_t v1;
133 uint64_t v2;
134 uint64_t v3;
135 uint64_t v4;
136 uint64_t mem64[4];
137 uint32_t memsize;
138 };
139
140 /**
141 * xxh32_reset() - reset the xxh32 state to start a new hashing operation
142 *
143 * @state: The xxh32 state to reset.
144 * @seed: Initialize the hash state with this seed.
145 *
146 * Call this function on any xxh32_state to prepare for a new hashing operation.
147 */
148 void xxh32_reset(struct xxh32_state *state, uint32_t seed);
149
150 /**
151 * xxh32_update() - hash the data given and update the xxh32 state
152 *
153 * @state: The xxh32 state to update.
154 * @input: The data to hash.
155 * @length: The length of the data to hash.
156 *
157 * After calling xxh32_reset() call xxh32_update() as many times as necessary.
158 *
159 * Return: Zero on success, otherwise an error code.
160 */
161 int xxh32_update(struct xxh32_state *state, const void *input, size_t length);
162
163 /**
164 * xxh32_digest() - produce the current xxh32 hash
165 *
166 * @state: Produce the current xxh32 hash of this state.
167 *
168 * A hash value can be produced at any time. It is still possible to continue
169 * inserting input into the hash state after a call to xxh32_digest(), and
170 * generate new hashes later on, by calling xxh32_digest() again.
171 *
172 * Return: The xxh32 hash stored in the state.
173 */
174 uint32_t xxh32_digest(const struct xxh32_state *state);
175
176 /**
177 * xxh64_reset() - reset the xxh64 state to start a new hashing operation
178 *
179 * @state: The xxh64 state to reset.
180 * @seed: Initialize the hash state with this seed.
181 */
182 void xxh64_reset(struct xxh64_state *state, uint64_t seed);
183
184 /**
185 * xxh64_update() - hash the data given and update the xxh64 state
186 * @state: The xxh64 state to update.
187 * @input: The data to hash.
188 * @length: The length of the data to hash.
189 *
190 * After calling xxh64_reset() call xxh64_update() as many times as necessary.
191 *
192 * Return: Zero on success, otherwise an error code.
193 */
194 int xxh64_update(struct xxh64_state *state, const void *input, size_t length);
195
196 /**
197 * xxh64_digest() - produce the current xxh64 hash
198 *
199 * @state: Produce the current xxh64 hash of this state.
200 *
201 * A hash value can be produced at any time. It is still possible to continue
202 * inserting input into the hash state after a call to xxh64_digest(), and
203 * generate new hashes later on, by calling xxh64_digest() again.
204 *
205 * Return: The xxh64 hash stored in the state.
206 */
207 uint64_t xxh64_digest(const struct xxh64_state *state);
208
209 /*-**************************
210 * Utils
211 ***************************/
212
213 /**
214 * xxh32_copy_state() - copy the source state into the destination state
215 *
216 * @src: The source xxh32 state.
217 * @dst: The destination xxh32 state.
218 */
219 void xxh32_copy_state(struct xxh32_state *dst, const struct xxh32_state *src);
220
221 /**
222 * xxh64_copy_state() - copy the source state into the destination state
223 *
224 * @src: The source xxh64 state.
225 * @dst: The destination xxh64 state.
226 */
227 void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src);
228
229 #endif /* XXHASH_H */
230