xref: /freebsd/sys/contrib/openzfs/module/zstd/lib/common/xxhash.h (revision 61145dc2b94f12f6a47344fb9aac702321880e43)
1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0-only
2 /*
3  * xxHash - Extremely Fast Hash algorithm
4  * Header File
5  * Copyright (c) 2012-2020, Yann Collet, Facebook, Inc.
6  *
7  * You can contact the author at :
8  * - xxHash source repository : https://github.com/Cyan4973/xxHash
9  *
10  * This source code is licensed under both the BSD-style license (found in the
11  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
12  * in the COPYING file in the root directory of this source tree).
13  * You may select, at your option, one of the above-listed licenses.
14 */
15 
16 /* Notice extracted from xxHash homepage :
17 
18 xxHash is an extremely fast Hash algorithm, running at RAM speed limits.
19 It also successfully passes all tests from the SMHasher suite.
20 
21 Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2 Duo @3GHz)
22 
23 Name            Speed       Q.Score   Author
24 xxHash          5.4 GB/s     10
25 CrapWow         3.2 GB/s      2       Andrew
26 MumurHash 3a    2.7 GB/s     10       Austin Appleby
27 SpookyHash      2.0 GB/s     10       Bob Jenkins
28 SBox            1.4 GB/s      9       Bret Mulvey
29 Lookup3         1.2 GB/s      9       Bob Jenkins
30 SuperFastHash   1.2 GB/s      1       Paul Hsieh
31 CityHash64      1.05 GB/s    10       Pike & Alakuijala
32 FNV             0.55 GB/s     5       Fowler, Noll, Vo
33 CRC32           0.43 GB/s     9
34 MD5-32          0.33 GB/s    10       Ronald L. Rivest
35 SHA1-32         0.28 GB/s    10
36 
37 Q.Score is a measure of quality of the hash function.
38 It depends on successfully passing SMHasher test set.
39 10 is a perfect score.
40 
41 A 64-bits version, named XXH64, is available since r35.
42 It offers much better speed, but for 64-bits applications only.
43 Name     Speed on 64 bits    Speed on 32 bits
44 XXH64       13.8 GB/s            1.9 GB/s
45 XXH32        6.8 GB/s            6.0 GB/s
46 */
47 
48 #if defined (__cplusplus)
49 extern "C" {
50 #endif
51 
52 #ifndef XXHASH_H_5627135585666179
53 #define XXHASH_H_5627135585666179 1
54 
55 
56 /* ****************************
57 *  Definitions
58 ******************************/
59 #include <stddef.h>   /* size_t */
60 typedef enum { XXH_OK=0, XXH_ERROR } XXH_errorcode;
61 
62 
63 /* ****************************
64 *  API modifier
65 ******************************/
66 /** XXH_PRIVATE_API
67 *   This is useful if you want to include xxhash functions in `static` mode
68 *   in order to inline them, and remove their symbol from the public list.
69 *   Methodology :
70 *     #define XXH_PRIVATE_API
71 *     #include "xxhash.h"
72 *   `xxhash.c` is automatically included.
73 *   It's not useful to compile and link it as a separate module anymore.
74 */
75 #ifdef XXH_PRIVATE_API
76 #  ifndef XXH_STATIC_LINKING_ONLY
77 #    define XXH_STATIC_LINKING_ONLY
78 #  endif
79 #  if defined(__GNUC__)
80 #    define XXH_PUBLIC_API static __inline __attribute__((unused))
81 #  elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
82 #    define XXH_PUBLIC_API static inline
83 #  elif defined(_MSC_VER)
84 #    define XXH_PUBLIC_API static __inline
85 #  else
86 #    define XXH_PUBLIC_API static   /* this version may generate warnings for unused static functions; disable the relevant warning */
87 #  endif
88 #else
89 #  define XXH_PUBLIC_API   /* do nothing */
90 #endif /* XXH_PRIVATE_API */
91 
92 /*!XXH_NAMESPACE, aka Namespace Emulation :
93 
94 If you want to include _and expose_ xxHash functions from within your own library,
95 but also want to avoid symbol collisions with another library which also includes xxHash,
96 
97 you can use XXH_NAMESPACE, to automatically prefix any public symbol from xxhash library
98 with the value of XXH_NAMESPACE (so avoid to keep it NULL and avoid numeric values).
99 
100 Note that no change is required within the calling program as long as it includes `xxhash.h` :
101 regular symbol name will be automatically translated by this header.
102 */
103 #ifdef XXH_NAMESPACE
104 #  define XXH_CAT(A,B) A##B
105 #  define XXH_NAME2(A,B) XXH_CAT(A,B)
106 #  define XXH32 XXH_NAME2(XXH_NAMESPACE, XXH32)
107 #  define XXH64 XXH_NAME2(XXH_NAMESPACE, XXH64)
108 #  define XXH_versionNumber XXH_NAME2(XXH_NAMESPACE, XXH_versionNumber)
109 #  define XXH32_createState XXH_NAME2(XXH_NAMESPACE, XXH32_createState)
110 #  define XXH64_createState XXH_NAME2(XXH_NAMESPACE, XXH64_createState)
111 #  define XXH32_freeState XXH_NAME2(XXH_NAMESPACE, XXH32_freeState)
112 #  define XXH64_freeState XXH_NAME2(XXH_NAMESPACE, XXH64_freeState)
113 #  define XXH32_reset XXH_NAME2(XXH_NAMESPACE, XXH32_reset)
114 #  define XXH64_reset XXH_NAME2(XXH_NAMESPACE, XXH64_reset)
115 #  define XXH32_update XXH_NAME2(XXH_NAMESPACE, XXH32_update)
116 #  define XXH64_update XXH_NAME2(XXH_NAMESPACE, XXH64_update)
117 #  define XXH32_digest XXH_NAME2(XXH_NAMESPACE, XXH32_digest)
118 #  define XXH64_digest XXH_NAME2(XXH_NAMESPACE, XXH64_digest)
119 #  define XXH32_copyState XXH_NAME2(XXH_NAMESPACE, XXH32_copyState)
120 #  define XXH64_copyState XXH_NAME2(XXH_NAMESPACE, XXH64_copyState)
121 #  define XXH32_canonicalFromHash XXH_NAME2(XXH_NAMESPACE, XXH32_canonicalFromHash)
122 #  define XXH64_canonicalFromHash XXH_NAME2(XXH_NAMESPACE, XXH64_canonicalFromHash)
123 #  define XXH32_hashFromCanonical XXH_NAME2(XXH_NAMESPACE, XXH32_hashFromCanonical)
124 #  define XXH64_hashFromCanonical XXH_NAME2(XXH_NAMESPACE, XXH64_hashFromCanonical)
125 #endif
126 
127 
128 /* *************************************
129 *  Version
130 ***************************************/
131 #define XXH_VERSION_MAJOR    0
132 #define XXH_VERSION_MINOR    6
133 #define XXH_VERSION_RELEASE  2
134 #define XXH_VERSION_NUMBER  (XXH_VERSION_MAJOR *100*100 + XXH_VERSION_MINOR *100 + XXH_VERSION_RELEASE)
135 XXH_PUBLIC_API unsigned XXH_versionNumber (void);
136 
137 
138 /* ****************************
139 *  Simple Hash Functions
140 ******************************/
141 typedef unsigned int       XXH32_hash_t;
142 typedef unsigned long long XXH64_hash_t;
143 
144 XXH_PUBLIC_API XXH32_hash_t XXH32 (const void* input, size_t length, unsigned int seed);
145 XXH_PUBLIC_API XXH64_hash_t XXH64 (const void* input, size_t length, unsigned long long seed);
146 
147 /*!
148 XXH32() :
149     Calculate the 32-bits hash of sequence "length" bytes stored at memory address "input".
150     The memory between input & input+length must be valid (allocated and read-accessible).
151     "seed" can be used to alter the result predictably.
152     Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s
153 XXH64() :
154     Calculate the 64-bits hash of sequence of length "len" stored at memory address "input".
155     "seed" can be used to alter the result predictably.
156     This function runs 2x faster on 64-bits systems, but slower on 32-bits systems (see benchmark).
157 */
158 
159 
160 /* ****************************
161 *  Streaming Hash Functions
162 ******************************/
163 typedef struct XXH32_state_s XXH32_state_t;   /* incomplete type */
164 typedef struct XXH64_state_s XXH64_state_t;   /* incomplete type */
165 
166 /*! State allocation, compatible with dynamic libraries */
167 
168 XXH_PUBLIC_API XXH32_state_t* XXH32_createState(void);
169 XXH_PUBLIC_API XXH_errorcode  XXH32_freeState(XXH32_state_t* statePtr);
170 
171 XXH_PUBLIC_API XXH64_state_t* XXH64_createState(void);
172 XXH_PUBLIC_API XXH_errorcode  XXH64_freeState(XXH64_state_t* statePtr);
173 
174 
175 /* hash streaming */
176 
177 XXH_PUBLIC_API XXH_errorcode XXH32_reset  (XXH32_state_t* statePtr, unsigned int seed);
178 XXH_PUBLIC_API XXH_errorcode XXH32_update (XXH32_state_t* statePtr, const void* input, size_t length);
179 XXH_PUBLIC_API XXH32_hash_t  XXH32_digest (const XXH32_state_t* statePtr);
180 
181 XXH_PUBLIC_API XXH_errorcode XXH64_reset  (XXH64_state_t* statePtr, unsigned long long seed);
182 XXH_PUBLIC_API XXH_errorcode XXH64_update (XXH64_state_t* statePtr, const void* input, size_t length);
183 XXH_PUBLIC_API XXH64_hash_t  XXH64_digest (const XXH64_state_t* statePtr);
184 
185 /*
186 These functions generate the xxHash of an input provided in multiple segments.
187 Note that, for small input, they are slower than single-call functions, due to state management.
188 For small input, prefer `XXH32()` and `XXH64()` .
189 
190 XXH state must first be allocated, using XXH*_createState() .
191 
192 Start a new hash by initializing state with a seed, using XXH*_reset().
193 
194 Then, feed the hash state by calling XXH*_update() as many times as necessary.
195 Obviously, input must be allocated and read accessible.
196 The function returns an error code, with 0 meaning OK, and any other value meaning there is an error.
197 
198 Finally, a hash value can be produced anytime, by using XXH*_digest().
199 This function returns the nn-bits hash as an int or long long.
200 
201 It's still possible to continue inserting input into the hash state after a digest,
202 and generate some new hashes later on, by calling again XXH*_digest().
203 
204 When done, free XXH state space if it was allocated dynamically.
205 */
206 
207 
208 /* **************************
209 *  Utils
210 ****************************/
211 #if !(defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L))   /* ! C99 */
212 #  define restrict   /* disable restrict */
213 #endif
214 
215 XXH_PUBLIC_API void XXH32_copyState(XXH32_state_t* restrict dst_state, const XXH32_state_t* restrict src_state);
216 XXH_PUBLIC_API void XXH64_copyState(XXH64_state_t* restrict dst_state, const XXH64_state_t* restrict src_state);
217 
218 
219 /* **************************
220 *  Canonical representation
221 ****************************/
222 /* Default result type for XXH functions are primitive unsigned 32 and 64 bits.
223 *  The canonical representation uses human-readable write convention, aka big-endian (large digits first).
224 *  These functions allow transformation of hash result into and from its canonical format.
225 *  This way, hash values can be written into a file / memory, and remain comparable on different systems and programs.
226 */
227 typedef struct { unsigned char digest[4]; } XXH32_canonical_t;
228 typedef struct { unsigned char digest[8]; } XXH64_canonical_t;
229 
230 XXH_PUBLIC_API void XXH32_canonicalFromHash(XXH32_canonical_t* dst, XXH32_hash_t hash);
231 XXH_PUBLIC_API void XXH64_canonicalFromHash(XXH64_canonical_t* dst, XXH64_hash_t hash);
232 
233 XXH_PUBLIC_API XXH32_hash_t XXH32_hashFromCanonical(const XXH32_canonical_t* src);
234 XXH_PUBLIC_API XXH64_hash_t XXH64_hashFromCanonical(const XXH64_canonical_t* src);
235 
236 #endif /* XXHASH_H_5627135585666179 */
237 
238 
239 
240 /* ================================================================================================
241    This section contains definitions which are not guaranteed to remain stable.
242    They may change in future versions, becoming incompatible with a different version of the library.
243    They shall only be used with static linking.
244    Never use these definitions in association with dynamic linking !
245 =================================================================================================== */
246 #if defined(XXH_STATIC_LINKING_ONLY) && !defined(XXH_STATIC_H_3543687687345)
247 #define XXH_STATIC_H_3543687687345
248 
249 /* These definitions are only meant to allow allocation of XXH state
250    statically, on stack, or in a struct for example.
251    Do not use members directly. */
252 
253    struct XXH32_state_s {
254        unsigned total_len_32;
255        unsigned large_len;
256        unsigned v1;
257        unsigned v2;
258        unsigned v3;
259        unsigned v4;
260        unsigned mem32[4];   /* buffer defined as U32 for alignment */
261        unsigned memsize;
262        unsigned reserved;   /* never read nor write, will be removed in a future version */
263    };   /* typedef'd to XXH32_state_t */
264 
265    struct XXH64_state_s {
266        unsigned long long total_len;
267        unsigned long long v1;
268        unsigned long long v2;
269        unsigned long long v3;
270        unsigned long long v4;
271        unsigned long long mem64[4];   /* buffer defined as U64 for alignment */
272        unsigned memsize;
273        unsigned reserved[2];          /* never read nor write, will be removed in a future version */
274    };   /* typedef'd to XXH64_state_t */
275 
276 
277 #  ifdef XXH_PRIVATE_API
278 #    include "xxhash.c"   /* include xxhash functions as `static`, for inlining */
279 #  endif
280 
281 #endif /* XXH_STATIC_LINKING_ONLY && XXH_STATIC_H_3543687687345 */
282 
283 
284 #if defined (__cplusplus)
285 }
286 #endif
287