2 xxHash - Fast Hash algorithm
4 Copyright (C) 2012-2014, Yann Collet.
5 BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
7 Redistribution and use in source and binary forms, with or without
8 modification, are permitted provided that the following conditions are
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
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.
30 You can contact the author at :
31 - xxHash source repository : http://code.google.com/p/xxhash/
34 /* Notice extracted from xxHash homepage :
36 xxHash is an extremely fast Hash algorithm, running at RAM speed limits.
37 It also successfully passes all tests from the SMHasher suite.
39 Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2 Duo @3GHz)
41 Name Speed Q.Score Author
43 CrapWow 3.2 GB/s 2 Andrew
44 MumurHash 3a 2.7 GB/s 10 Austin Appleby
45 SpookyHash 2.0 GB/s 10 Bob Jenkins
46 SBox 1.4 GB/s 9 Bret Mulvey
47 Lookup3 1.2 GB/s 9 Bob Jenkins
48 SuperFastHash 1.2 GB/s 1 Paul Hsieh
49 CityHash64 1.05 GB/s 10 Pike & Alakuijala
50 FNV 0.55 GB/s 5 Fowler, Noll, Vo
52 MD5-32 0.33 GB/s 10 Ronald L. Rivest
55 Q.Score is a measure of quality of the hash function.
56 It depends on successfully passing SMHasher test set.
57 10 is a perfect score.
62 #if defined (__cplusplus)
80 //****************************
82 //****************************
83 typedef enum { XXH_OK=0, XXH_ERROR } XXH_errorcode;
87 //****************************
88 // Simple Hash Functions
89 //****************************
91 uint32_t XXH32 (const void* input, uint32_t len, uint32_t seed);
95 Calculate the 32-bits hash of sequence of length "len" stored at memory address "input".
96 The memory between input & input+len must be valid (allocated and read-accessible).
97 "seed" can be used to alter the result predictably.
98 This function successfully passes all SMHasher tests.
99 Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s
100 Note that "len" is type "int", which means it is limited to 2^31-1.
101 If your data is larger, use the advanced functions below.
106 //****************************
107 // Advanced Hash Functions
108 //****************************
110 void* XXH32_init (uint32_t seed);
111 XXH_errorcode XXH32_update (void* state, const void* input, int len);
112 uint32_t XXH32_digest (void* state);
115 These functions calculate the xxhash of an input provided in several small packets,
116 as opposed to an input provided as a single block.
118 It must be started with :
120 The function returns a pointer which holds the state of calculation.
122 This pointer must be provided as "void* state" parameter for XXH32_update().
123 XXH32_update() can be called as many times as necessary.
124 The user must provide a valid (allocated) input.
125 The function returns an error code, with 0 meaning OK, and any other value meaning there is an error.
126 Note that "len" is type "int", which means it is limited to 2^31-1.
127 If your data is larger, it is recommended to chunk your data into blocks
128 of size for example 2^30 (1GB) to avoid any "int" overflow issue.
130 Finally, you can end the calculation anytime, by using XXH32_digest().
131 This function returns the final 32-bits hash.
132 You must provide the same "void* state" parameter created by XXH32_init().
133 Memory will be freed by XXH32_digest().
137 int XXH32_sizeofState(void);
138 XXH_errorcode XXH32_resetState(void* state, uint32_t seed);
140 #define XXH32_SIZEOFSTATE 48
141 typedef struct { long long ll[(XXH32_SIZEOFSTATE+(sizeof(long long)-1))/sizeof(long long)]; } XXH32_stateSpace_t;
143 These functions allow user application to make its own allocation for state.
145 XXH32_sizeofState() is used to know how much space must be allocated for the xxHash 32-bits state.
146 Note that the state must be aligned to access 'long long' fields. Memory must be allocated and referenced by a pointer.
147 This pointer must then be provided as 'state' into XXH32_resetState(), which initializes the state.
149 For static allocation purposes (such as allocation on stack, or freestanding systems without malloc()),
150 use the structure XXH32_stateSpace_t, which will ensure that memory space is large enough and correctly aligned to access 'long long' fields.
154 uint32_t XXH32_intermediateDigest (void* state);
156 This function does the same as XXH32_digest(), generating a 32-bit hash,
157 but preserve memory context.
158 This way, it becomes possible to generate intermediate hashes, and then continue feeding data with XXH32_update().
159 To free memory context, use XXH32_digest(), or free().
164 //****************************
165 // Deprecated function names
166 //****************************
167 // The following translations are provided to ease code transition
168 // You are encouraged to no longer this function names
169 #define XXH32_feed XXH32_update
170 #define XXH32_result XXH32_digest
171 #define XXH32_getIntermediateResult XXH32_intermediateDigest
175 #if defined (__cplusplus)