deimos.lz4.xxHash source code

1 module deimos.lz4.xxHash;
2 /*
3    xxHash - Fast Hash algorithm
4    Header File
5    Copyright (C) 2012-2013, Yann Collet.
6    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
7 
8    Redistribution and use in source and binary forms, with or without
9    modification, are permitted provided that the following conditions are
10    met:
11 
12        * Redistributions of source code must retain the above copyright
13    notice, this list of conditions and the following disclaimer.
14        * Redistributions in binary form must reproduce the above
15    copyright notice, this list of conditions and the following disclaimer
16    in the documentation and/or other materials provided with the
17    distribution.
18 
19    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 
31    You can contact the author at :
32    - xxHash source repository : http://code.google.com/p/xxhash/
33 */
34 
35 /* Notice extracted from xxHash homepage :
36 
37 xxHash is an extremely fast Hash algorithm, running at RAM speed limits.
38 It also successfully passes all tests from the SMHasher suite.
39 
40 Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2 Duo @3GHz)
41 
42 Name            Speed       Q.Score   Author
43 xxHash          5.4 GB/s     10
44 CrapWow         3.2 GB/s      2       Andrew
45 MumurHash 3a    2.7 GB/s     10       Austin Appleby
46 SpookyHash      2.0 GB/s     10       Bob Jenkins
47 SBox            1.4 GB/s      9       Bret Mulvey
48 Lookup3         1.2 GB/s      9       Bob Jenkins
49 SuperFastHash   1.2 GB/s      1       Paul Hsieh
50 CityHash64      1.05 GB/s    10       Pike & Alakuijala
51 FNV             0.55 GB/s     5       Fowler, Noll, Vo
52 CRC32           0.43 GB/s     9
53 MD5-32          0.33 GB/s    10       Ronald L. Rivest
54 SHA1-32         0.28 GB/s    10
55 
56 Q.Score is a measure of quality of the hash function.
57 It depends on successfully passing SMHasher test set.
58 10 is a perfect score.
59 */
60 
61 extern (C) nothrow:
62 
63 
64 //****************************
65 // Type
66 //****************************
67 enum XXH_errorcode { XXH_OK=0, XXH_ERROR }
68 
69 
70 
71 //****************************
72 // Simple Hash Functions
73 //****************************
74 
75 uint XXH32 (in void* input, int len, uint seed);
76 
77 /*
78 XXH32() :
79     Calculate the 32-bits hash of sequence of length "len" stored at memory address "input".
80     The memory between input & input+len must be valid (allocated and read-accessible).
81     "seed" can be used to alter the result predictably.
82     This function successfully passes all SMHasher tests.
83     Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s
84     Note that "len" is type "int", which means it is limited to 2^31-1.
85     If your data is larger, use the advanced functions below.
86 */
87 
88 
89 
90 //****************************
91 // Advanced Hash Functions
92 //****************************
93 
94 void*         XXH32_init   (uint seed);
95 XXH_errorcode XXH32_update (void* state, in void* input, int len);
96 uint          XXH32_digest (void* state);
97 
98 /*
99 These functions calculate the xxhash of an input provided in several small packets,
100 as opposed to an input provided as a single block.
101 
102 It must be started with :
103 void* XXH32_init()
104 The function returns a pointer which holds the state of calculation.
105 
106 This pointer must be provided as "void* state" parameter for XXH32_update().
107 XXH32_update() can be called as many times as necessary.
108 The user must provide a valid (allocated) input.
109 The function returns an error code, with 0 meaning OK, and any other value meaning there is an error.
110 Note that "len" is type "int", which means it is limited to 2^31-1.
111 If your data is larger, it is recommended to chunk your data into blocks
112 of size for example 2^30 (1GB) to avoid any "int" overflow issue.
113 
114 Finally, you can end the calculation anytime, by using XXH32_digest().
115 This function returns the final 32-bits hash.
116 You must provide the same "void* state" parameter created by XXH32_init().
117 Memory will be freed by XXH32_digest().
118 */
119 
120 
121 int           XXH32_sizeofState();
122 XXH_errorcode XXH32_resetState(void* state, uint seed);
123 
124 enum XXH32_SIZEOFSTATE = 48;
125 struct XXH32_stateSpace_t { long ll[ (XXH32_SIZEOFSTATE+(long.sizeof)-1) /long.sizeof]; }
126 /*
127 These functions allow user application to make its own allocation for state.
128 
129 XXH32_sizeofState() is used to know how much space must be allocated for the xxHash 32-bits state.
130 Note that the state must be aligned to access 'long long' fields. Memory must be allocated and referenced by a pointer.
131 This pointer must then be provided as 'state' into XXH32_resetState(), which initializes the state.
132 
133 For static allocation purposes (such as allocation on stack, or freestanding systems without malloc()),
134 use the structure XXH32_stateSpace_t, which will ensure that memory space is large enough and correctly aligned to access 'long long' fields.
135 */
136 
137 
138 uint XXH32_intermediateDigest (void* state);
139 /*
140 This function does the same as XXH32_digest(), generating a 32-bit hash,
141 but preserve memory context.
142 This way, it becomes possible to generate intermediate hashes, and then continue feeding data with XXH32_update().
143 To free memory context, use XXH32_digest(), or free().
144 */
145 
146 
147 
148 //****************************
149 // Deprecated function names
150 //****************************
151 // The following translations are provided to ease code transition
152 // You are encouraged to no longer this function names
153 alias XXH32_feed   = XXH32_update;
154 alias XXH32_result = XXH32_digest;
155 alias XXH32_getIntermediateResult = XXH32_intermediateDigest;