-
-
Notifications
You must be signed in to change notification settings - Fork 178
/
Spooky.h
298 lines (272 loc) · 11.2 KB
/
Spooky.h
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
//
// SpookyHash V1: a 128-bit noncryptographic hash function
// By Bob Jenkins, public domain
// Oct 31 2010: alpha, framework + SpookyHash::Mix appears right
// Oct 31 2011: alpha again, Mix only good to 2^^69 but rest appears right
// Dec 31 2011: beta, improved Mix, tested it for 2-bit deltas
// Feb 2 2012: production, same bits as beta
// Feb 5 2012: adjusted definitions of uint* to be more portable
// Oct 2021: renamed to SpookyHashV1 (use V2 instead)
//
// Up to 4 bytes/cycle for long messages. Reasonably fast for short messages.
// All 1 or 2 bit deltas achieve avalanche within 1% bias per output bit.
//
// This was developed for and tested on 64-bit x86-compatible processors.
// It assumes the processor is little-endian. There is a macro
// controlling whether unaligned reads are allowed (by default they are).
// This should be an equally good hash on big-endian machines, but it will
// compute different results on them than on little-endian machines.
//
// Google's CityHash has similar specs to SpookyHash, and CityHash is faster
// on some platforms. MD4 and MD5 also have similar specs, but they are orders
// of magnitude slower. CRCs are two or more times slower, but unlike
// SpookyHash, they have nice math for combining the CRCs of pieces to form
// the CRCs of wholes. There are also cryptographic hashes, but those are even
// slower than MD5.
//
// rurban: Note that this old version has UB and a known bad seed of 0x26bb3cda.
// Rather use the better V2 instead.
//
#include "Platform.h"
#include <stddef.h>
#ifdef _MSC_VER
# define INLINE __forceinline
typedef unsigned __int64 uint64;
typedef unsigned __int32 uint32;
typedef unsigned __int16 uint16;
typedef unsigned __int8 uint8;
#else
# include <stdint.h>
# define INLINE inline
typedef uint64_t uint64;
typedef uint32_t uint32;
typedef uint16_t uint16;
typedef uint8_t uint8;
#endif
class SpookyHashV1
{
public:
//
// SpookyHash: hash a single message in one call, produce 128-bit output
//
static void Hash128(
const void *message, // message to hash
size_t length, // length of message in bytes
uint64 *hash1, // in/out: in seed 1, out hash value 1
uint64 *hash2); // in/out: in seed 2, out hash value 2
//
// Hash64: hash a single message in one call, return 64-bit output
//
static uint64 Hash64(
const void *message, // message to hash
size_t length, // length of message in bytes
uint64 seed) // seed
{
uint64 hash1 = seed;
Hash128(message, length, &hash1, &seed);
return hash1;
}
//
// Hash32: hash a single message in one call, produce 32-bit output
//
static uint32 Hash32(
const void *message, // message to hash
size_t length, // length of message in bytes
uint32 seed) // seed
{
uint64 hash1 = seed, hash2 = seed;
Hash128(message, length, &hash1, &hash2);
return (uint32)hash1;
}
//
// Init: initialize the context of a SpookyHash
//
void Init(
uint64 seed1, // any 64-bit value will do, including 0
uint64 seed2); // different seeds produce independent hashes
//
// Update: add a piece of a message to a SpookyHash state
//
void Update(
const void *message, // message fragment
size_t length); // length of message fragment in bytes
//
// Final: compute the hash for the current SpookyHash state
//
// This does not modify the state; you can keep updating it afterward
//
// The result is the same as if SpookyHash() had been called with
// all the pieces concatenated into one message.
//
void Final(
uint64 *hash1, // out only: first 64 bits of hash value.
uint64 *hash2); // out only: second 64 bits of hash value.
//
// left rotate a 64-bit value by k bytes
//
static INLINE uint64 Rot64(uint64 x, int k)
{
return (x << k) | (x >> (64 - k));
}
//
// This is used if the input is 96 bytes long or longer.
//
// The internal state is fully overwritten every 96 bytes.
// Every input bit appears to cause at least 128 bits of entropy
// before 96 other bytes are combined, when run forward or backward
// For every input bit,
// Two inputs differing in just that input bit
// Where "differ" means xor or subtraction
// And the base value is random
// When run forward or backwards one Mix
// I tried 3 pairs of each; they all differed by at least 212 bits.
//
static INLINE void Mix(
const uint64 *data,
uint64 &s0, uint64 &s1, uint64 &s2, uint64 &s3,
uint64 &s4, uint64 &s5, uint64 &s6, uint64 &s7,
uint64 &s8, uint64 &s9, uint64 &s10,uint64 &s11)
{
s0 += data[0]; s2 ^= s10; s11 ^= s0; s0 = Rot64(s0,11); s11 += s1;
s1 += data[1]; s3 ^= s11; s0 ^= s1; s1 = Rot64(s1,32); s0 += s2;
s2 += data[2]; s4 ^= s0; s1 ^= s2; s2 = Rot64(s2,43); s1 += s3;
s3 += data[3]; s5 ^= s1; s2 ^= s3; s3 = Rot64(s3,31); s2 += s4;
s4 += data[4]; s6 ^= s2; s3 ^= s4; s4 = Rot64(s4,17); s3 += s5;
s5 += data[5]; s7 ^= s3; s4 ^= s5; s5 = Rot64(s5,28); s4 += s6;
s6 += data[6]; s8 ^= s4; s5 ^= s6; s6 = Rot64(s6,39); s5 += s7;
s7 += data[7]; s9 ^= s5; s6 ^= s7; s7 = Rot64(s7,57); s6 += s8;
s8 += data[8]; s10 ^= s6; s7 ^= s8; s8 = Rot64(s8,55); s7 += s9;
s9 += data[9]; s11 ^= s7; s8 ^= s9; s9 = Rot64(s9,54); s8 += s10;
s10 += data[10]; s0 ^= s8; s9 ^= s10; s10 = Rot64(s10,22); s9 += s11;
s11 += data[11]; s1 ^= s9; s10 ^= s11; s11 = Rot64(s11,46); s10 += s0;
}
//
// Mix all 12 inputs together so that h0, h1 are a hash of them all.
//
// For two inputs differing in just the input bits
// Where "differ" means xor or subtraction
// And the base value is random, or a counting value starting at that bit
// The final result will have each bit of h0, h1 flip
// For every input bit,
// with probability 50 +- .3%
// For every pair of input bits,
// with probability 50 +- 3%
//
// This does not rely on the last Mix() call having already mixed some.
// Two iterations was almost good enough for a 64-bit result, but a
// 128-bit result is reported, so End() does three iterations.
//
static INLINE void EndPartial(
uint64 &h0, uint64 &h1, uint64 &h2, uint64 &h3,
uint64 &h4, uint64 &h5, uint64 &h6, uint64 &h7,
uint64 &h8, uint64 &h9, uint64 &h10,uint64 &h11)
{
h11+= h1; h2 ^= h11; h1 = Rot64(h1,44);
h0 += h2; h3 ^= h0; h2 = Rot64(h2,15);
h1 += h3; h4 ^= h1; h3 = Rot64(h3,34);
h2 += h4; h5 ^= h2; h4 = Rot64(h4,21);
h3 += h5; h6 ^= h3; h5 = Rot64(h5,38);
h4 += h6; h7 ^= h4; h6 = Rot64(h6,33);
h5 += h7; h8 ^= h5; h7 = Rot64(h7,10);
h6 += h8; h9 ^= h6; h8 = Rot64(h8,13);
h7 += h9; h10^= h7; h9 = Rot64(h9,38);
h8 += h10; h11^= h8; h10= Rot64(h10,53);
h9 += h11; h0 ^= h9; h11= Rot64(h11,42);
h10+= h0; h1 ^= h10; h0 = Rot64(h0,54);
}
static INLINE void End(
uint64 &h0, uint64 &h1, uint64 &h2, uint64 &h3,
uint64 &h4, uint64 &h5, uint64 &h6, uint64 &h7,
uint64 &h8, uint64 &h9, uint64 &h10,uint64 &h11)
{
EndPartial(h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11);
EndPartial(h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11);
EndPartial(h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11);
}
//
// The goal is for each bit of the input to expand into 128 bits of
// apparent entropy before it is fully overwritten.
// n trials both set and cleared at least m bits of h0 h1 h2 h3
// n: 2 m: 29
// n: 3 m: 46
// n: 4 m: 57
// n: 5 m: 107
// n: 6 m: 146
// n: 7 m: 152
// when run forwards or backwards
// for all 1-bit and 2-bit diffs
// with diffs defined by either xor or subtraction
// with a base of all zeros plus a counter, or plus another bit, or random
//
static INLINE void ShortMix(uint64 &h0, uint64 &h1, uint64 &h2, uint64 &h3)
{
h2 = Rot64(h2,50); h2 += h3; h0 ^= h2;
h3 = Rot64(h3,52); h3 += h0; h1 ^= h3;
h0 = Rot64(h0,30); h0 += h1; h2 ^= h0;
h1 = Rot64(h1,41); h1 += h2; h3 ^= h1;
h2 = Rot64(h2,54); h2 += h3; h0 ^= h2;
h3 = Rot64(h3,48); h3 += h0; h1 ^= h3;
h0 = Rot64(h0,38); h0 += h1; h2 ^= h0;
h1 = Rot64(h1,37); h1 += h2; h3 ^= h1;
h2 = Rot64(h2,62); h2 += h3; h0 ^= h2;
h3 = Rot64(h3,34); h3 += h0; h1 ^= h3;
h0 = Rot64(h0,5); h0 += h1; h2 ^= h0;
h1 = Rot64(h1,36); h1 += h2; h3 ^= h1;
}
//
// Mix all 4 inputs together so that h0, h1 are a hash of them all.
//
// For two inputs differing in just the input bits
// Where "differ" means xor or subtraction
// And the base value is random, or a counting value starting at that bit
// The final result will have each bit of h0, h1 flip
// For every input bit,
// with probability 50 +- .3% (it is probably better than that)
// For every pair of input bits,
// with probability 50 +- .75% (the worst case is approximately that)
//
static INLINE void ShortEnd(uint64 &h0, uint64 &h1, uint64 &h2, uint64 &h3)
{
h3 ^= h2; h2 = Rot64(h2,15); h3 += h2;
h0 ^= h3; h3 = Rot64(h3,52); h0 += h3;
h1 ^= h0; h0 = Rot64(h0,26); h1 += h0;
h2 ^= h1; h1 = Rot64(h1,51); h2 += h1;
h3 ^= h2; h2 = Rot64(h2,28); h3 += h2;
h0 ^= h3; h3 = Rot64(h3,9); h0 += h3;
h1 ^= h0; h0 = Rot64(h0,47); h1 += h0;
h2 ^= h1; h1 = Rot64(h1,54); h2 += h1;
h3 ^= h2; h2 = Rot64(h2,32); h3 += h2;
h0 ^= h3; h3 = Rot64(h3,25); h0 += h3;
h1 ^= h0; h0 = Rot64(h0,63); h1 += h0;
}
private:
//
// Short is used for messages under 192 bytes in length
// Short has a low startup cost, the normal mode is good for long
// keys, the cost crossover is at about 192 bytes. The two modes were
// held to the same quality bar.
//
static void Short(
const void *message,
size_t length,
uint64 *hash1,
uint64 *hash2);
// number of uint64's in internal state
static const size_t sc_numVars = 12;
// size of the internal state
static const size_t sc_blockSize = sc_numVars*8;
// size of buffer of unhashed data, in bytes
static const size_t sc_bufSize = 2*sc_blockSize;
//
// sc_const: a constant which:
// * is not zero
// * is odd
// * is a not-very-regular mix of 1's and 0's
// * does not need any other special mathematical properties
//
static const uint64 sc_const = 0xdeadbeefdeadbeefULL;
uint64 m_data[2*sc_numVars]; // unhashed data, for partial messages
uint64 m_state[sc_numVars]; // internal state of the hash
size_t m_length; // total length of the input so far
uint8 m_remainder; // length of unhashed data stashed in m_data
};