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
|
/* Downloaded from http://sites.google.com/site/murmurhash/ which says "All
* code is released to the public domain. For business purposes, Murmurhash is
* under the MIT license."
* This is modified from the original:
* ULL tag on 0xc6a4a7935bd1e995 so this will compile on 32-bit.
* length changed to unsigned int.
* placed in namespace util
* add MurmurHashNative
* default option = 0 for seed
* ARM port from NICT
*/
#include "util/murmur_hash.hh"
#include <cstring>
namespace util {
//-----------------------------------------------------------------------------
// MurmurHash2, 64-bit versions, by Austin Appleby
// The same caveats as 32-bit MurmurHash2 apply here - beware of alignment
// and endian-ness issues if used across multiple platforms.
// 64-bit hash for 64-bit platforms
uint64_t MurmurHash64A ( const void * key, std::size_t len, uint64_t seed )
{
const uint64_t m = 0xc6a4a7935bd1e995ULL;
const int r = 47;
uint64_t h = seed ^ (len * m);
#if defined(__arm) || defined(__arm__)
const size_t ksize = sizeof(uint64_t);
const unsigned char * data = (const unsigned char *)key;
const unsigned char * end = data + (std::size_t)(len/8) * ksize;
#else
const uint64_t * data = (const uint64_t *)key;
const uint64_t * end = data + (len/8);
#endif
while(data != end)
{
#if defined(__arm) || defined(__arm__)
uint64_t k;
memcpy(&k, data, ksize);
data += ksize;
#else
uint64_t k = *data++;
#endif
k *= m;
k ^= k >> r;
k *= m;
h ^= k;
h *= m;
}
const unsigned char * data2 = (const unsigned char*)data;
switch(len & 7)
{
case 7: h ^= uint64_t(data2[6]) << 48;
case 6: h ^= uint64_t(data2[5]) << 40;
case 5: h ^= uint64_t(data2[4]) << 32;
case 4: h ^= uint64_t(data2[3]) << 24;
case 3: h ^= uint64_t(data2[2]) << 16;
case 2: h ^= uint64_t(data2[1]) << 8;
case 1: h ^= uint64_t(data2[0]);
h *= m;
};
h ^= h >> r;
h *= m;
h ^= h >> r;
return h;
}
// 64-bit hash for 32-bit platforms
uint64_t MurmurHash64B ( const void * key, std::size_t len, uint64_t seed )
{
const unsigned int m = 0x5bd1e995;
const int r = 24;
unsigned int h1 = seed ^ len;
unsigned int h2 = 0;
#if defined(__arm) || defined(__arm__)
size_t ksize = sizeof(unsigned int);
const unsigned char * data = (const unsigned char *)key;
#else
const unsigned int * data = (const unsigned int *)key;
#endif
unsigned int k1, k2;
while(len >= 8)
{
#if defined(__arm) || defined(__arm__)
memcpy(&k1, data, ksize);
data += ksize;
memcpy(&k2, data, ksize);
data += ksize;
#else
k1 = *data++;
k2 = *data++;
#endif
k1 *= m; k1 ^= k1 >> r; k1 *= m;
h1 *= m; h1 ^= k1;
len -= 4;
k2 *= m; k2 ^= k2 >> r; k2 *= m;
h2 *= m; h2 ^= k2;
len -= 4;
}
if(len >= 4)
{
#if defined(__arm) || defined(__arm__)
memcpy(&k1, data, ksize);
data += ksize;
#else
k1 = *data++;
#endif
k1 *= m; k1 ^= k1 >> r; k1 *= m;
h1 *= m; h1 ^= k1;
len -= 4;
}
switch(len)
{
case 3: h2 ^= ((unsigned char*)data)[2] << 16;
case 2: h2 ^= ((unsigned char*)data)[1] << 8;
case 1: h2 ^= ((unsigned char*)data)[0];
h2 *= m;
};
h1 ^= h2 >> 18; h1 *= m;
h2 ^= h1 >> 22; h2 *= m;
h1 ^= h2 >> 17; h1 *= m;
h2 ^= h1 >> 19; h2 *= m;
uint64_t h = h1;
h = (h << 32) | h2;
return h;
}
// Trick to test for 64-bit architecture at compile time.
namespace {
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-function"
#endif
template <unsigned L> inline uint64_t MurmurHashNativeBackend(const void * key, std::size_t len, uint64_t seed) {
return MurmurHash64A(key, len, seed);
}
template <> inline uint64_t MurmurHashNativeBackend<4>(const void * key, std::size_t len, uint64_t seed) {
return MurmurHash64B(key, len, seed);
}
#ifdef __clang__
#pragma clang diagnostic pop
#endif
} // namespace
uint64_t MurmurHashNative(const void * key, std::size_t len, uint64_t seed) {
return MurmurHashNativeBackend<sizeof(void*)>(key, len, seed);
}
} // namespace util
|
