1 #ifndef JEMALLOC_INTERNAL_HASH_H
2 #define JEMALLOC_INTERNAL_HASH_H
3
4 #include "jemalloc/internal/assert.h"
5
6 /*
7 * The following hash function is based on MurmurHash3, placed into the public
8 * domain by Austin Appleby. See https://github.com/aappleby/smhasher for
9 * details.
10 */
11
12 /******************************************************************************/
13 /* Internal implementation. */
14 static inline uint32_t
hash_rotl_32(uint32_t x,int8_t r)15 hash_rotl_32(uint32_t x, int8_t r) {
16 return ((x << r) | (x >> (32 - r)));
17 }
18
19 static inline uint64_t
hash_rotl_64(uint64_t x,int8_t r)20 hash_rotl_64(uint64_t x, int8_t r) {
21 return ((x << r) | (x >> (64 - r)));
22 }
23
24 static inline uint32_t
hash_get_block_32(const uint32_t * p,int i)25 hash_get_block_32(const uint32_t *p, int i) {
26 /* Handle unaligned read. */
27 if (unlikely((uintptr_t)p & (sizeof(uint32_t)-1)) != 0) {
28 uint32_t ret;
29
30 memcpy(&ret, (uint8_t *)(p + i), sizeof(uint32_t));
31 return ret;
32 }
33
34 return p[i];
35 }
36
37 static inline uint64_t
hash_get_block_64(const uint64_t * p,int i)38 hash_get_block_64(const uint64_t *p, int i) {
39 /* Handle unaligned read. */
40 if (unlikely((uintptr_t)p & (sizeof(uint64_t)-1)) != 0) {
41 uint64_t ret;
42
43 memcpy(&ret, (uint8_t *)(p + i), sizeof(uint64_t));
44 return ret;
45 }
46
47 return p[i];
48 }
49
50 static inline uint32_t
hash_fmix_32(uint32_t h)51 hash_fmix_32(uint32_t h) {
52 h ^= h >> 16;
53 h *= 0x85ebca6b;
54 h ^= h >> 13;
55 h *= 0xc2b2ae35;
56 h ^= h >> 16;
57
58 return h;
59 }
60
61 static inline uint64_t
hash_fmix_64(uint64_t k)62 hash_fmix_64(uint64_t k) {
63 k ^= k >> 33;
64 k *= KQU(0xff51afd7ed558ccd);
65 k ^= k >> 33;
66 k *= KQU(0xc4ceb9fe1a85ec53);
67 k ^= k >> 33;
68
69 return k;
70 }
71
72 static inline uint32_t
hash_x86_32(const void * key,int len,uint32_t seed)73 hash_x86_32(const void *key, int len, uint32_t seed) {
74 const uint8_t *data = (const uint8_t *) key;
75 const int nblocks = len / 4;
76
77 uint32_t h1 = seed;
78
79 const uint32_t c1 = 0xcc9e2d51;
80 const uint32_t c2 = 0x1b873593;
81
82 /* body */
83 {
84 const uint32_t *blocks = (const uint32_t *) (data + nblocks*4);
85 int i;
86
87 for (i = -nblocks; i; i++) {
88 uint32_t k1 = hash_get_block_32(blocks, i);
89
90 k1 *= c1;
91 k1 = hash_rotl_32(k1, 15);
92 k1 *= c2;
93
94 h1 ^= k1;
95 h1 = hash_rotl_32(h1, 13);
96 h1 = h1*5 + 0xe6546b64;
97 }
98 }
99
100 /* tail */
101 {
102 const uint8_t *tail = (const uint8_t *) (data + nblocks*4);
103
104 uint32_t k1 = 0;
105
106 switch (len & 3) {
107 case 3: k1 ^= tail[2] << 16; JEMALLOC_FALLTHROUGH
108 case 2: k1 ^= tail[1] << 8; JEMALLOC_FALLTHROUGH
109 case 1: k1 ^= tail[0]; k1 *= c1; k1 = hash_rotl_32(k1, 15);
110 k1 *= c2; h1 ^= k1;
111 }
112 }
113
114 /* finalization */
115 h1 ^= len;
116
117 h1 = hash_fmix_32(h1);
118
119 return h1;
120 }
121
122 static inline void
hash_x86_128(const void * key,const int len,uint32_t seed,uint64_t r_out[2])123 hash_x86_128(const void *key, const int len, uint32_t seed,
124 uint64_t r_out[2]) {
125 const uint8_t * data = (const uint8_t *) key;
126 const int nblocks = len / 16;
127
128 uint32_t h1 = seed;
129 uint32_t h2 = seed;
130 uint32_t h3 = seed;
131 uint32_t h4 = seed;
132
133 const uint32_t c1 = 0x239b961b;
134 const uint32_t c2 = 0xab0e9789;
135 const uint32_t c3 = 0x38b34ae5;
136 const uint32_t c4 = 0xa1e38b93;
137
138 /* body */
139 {
140 const uint32_t *blocks = (const uint32_t *) (data + nblocks*16);
141 int i;
142
143 for (i = -nblocks; i; i++) {
144 uint32_t k1 = hash_get_block_32(blocks, i*4 + 0);
145 uint32_t k2 = hash_get_block_32(blocks, i*4 + 1);
146 uint32_t k3 = hash_get_block_32(blocks, i*4 + 2);
147 uint32_t k4 = hash_get_block_32(blocks, i*4 + 3);
148
149 k1 *= c1; k1 = hash_rotl_32(k1, 15); k1 *= c2; h1 ^= k1;
150
151 h1 = hash_rotl_32(h1, 19); h1 += h2;
152 h1 = h1*5 + 0x561ccd1b;
153
154 k2 *= c2; k2 = hash_rotl_32(k2, 16); k2 *= c3; h2 ^= k2;
155
156 h2 = hash_rotl_32(h2, 17); h2 += h3;
157 h2 = h2*5 + 0x0bcaa747;
158
159 k3 *= c3; k3 = hash_rotl_32(k3, 17); k3 *= c4; h3 ^= k3;
160
161 h3 = hash_rotl_32(h3, 15); h3 += h4;
162 h3 = h3*5 + 0x96cd1c35;
163
164 k4 *= c4; k4 = hash_rotl_32(k4, 18); k4 *= c1; h4 ^= k4;
165
166 h4 = hash_rotl_32(h4, 13); h4 += h1;
167 h4 = h4*5 + 0x32ac3b17;
168 }
169 }
170
171 /* tail */
172 {
173 const uint8_t *tail = (const uint8_t *) (data + nblocks*16);
174 uint32_t k1 = 0;
175 uint32_t k2 = 0;
176 uint32_t k3 = 0;
177 uint32_t k4 = 0;
178
179 switch (len & 15) {
180 case 15: k4 ^= tail[14] << 16; JEMALLOC_FALLTHROUGH
181 case 14: k4 ^= tail[13] << 8; JEMALLOC_FALLTHROUGH
182 case 13: k4 ^= tail[12] << 0;
183 k4 *= c4; k4 = hash_rotl_32(k4, 18); k4 *= c1; h4 ^= k4;
184 JEMALLOC_FALLTHROUGH
185 case 12: k3 ^= tail[11] << 24; JEMALLOC_FALLTHROUGH
186 case 11: k3 ^= tail[10] << 16; JEMALLOC_FALLTHROUGH
187 case 10: k3 ^= tail[ 9] << 8; JEMALLOC_FALLTHROUGH
188 case 9: k3 ^= tail[ 8] << 0;
189 k3 *= c3; k3 = hash_rotl_32(k3, 17); k3 *= c4; h3 ^= k3;
190 JEMALLOC_FALLTHROUGH
191 case 8: k2 ^= tail[ 7] << 24; JEMALLOC_FALLTHROUGH
192 case 7: k2 ^= tail[ 6] << 16; JEMALLOC_FALLTHROUGH
193 case 6: k2 ^= tail[ 5] << 8; JEMALLOC_FALLTHROUGH
194 case 5: k2 ^= tail[ 4] << 0;
195 k2 *= c2; k2 = hash_rotl_32(k2, 16); k2 *= c3; h2 ^= k2;
196 JEMALLOC_FALLTHROUGH
197 case 4: k1 ^= tail[ 3] << 24; JEMALLOC_FALLTHROUGH
198 case 3: k1 ^= tail[ 2] << 16; JEMALLOC_FALLTHROUGH
199 case 2: k1 ^= tail[ 1] << 8; JEMALLOC_FALLTHROUGH
200 case 1: k1 ^= tail[ 0] << 0;
201 k1 *= c1; k1 = hash_rotl_32(k1, 15); k1 *= c2; h1 ^= k1;
202 break;
203 }
204 }
205
206 /* finalization */
207 h1 ^= len; h2 ^= len; h3 ^= len; h4 ^= len;
208
209 h1 += h2; h1 += h3; h1 += h4;
210 h2 += h1; h3 += h1; h4 += h1;
211
212 h1 = hash_fmix_32(h1);
213 h2 = hash_fmix_32(h2);
214 h3 = hash_fmix_32(h3);
215 h4 = hash_fmix_32(h4);
216
217 h1 += h2; h1 += h3; h1 += h4;
218 h2 += h1; h3 += h1; h4 += h1;
219
220 r_out[0] = (((uint64_t) h2) << 32) | h1;
221 r_out[1] = (((uint64_t) h4) << 32) | h3;
222 }
223
224 static inline void
hash_x64_128(const void * key,const int len,const uint32_t seed,uint64_t r_out[2])225 hash_x64_128(const void *key, const int len, const uint32_t seed,
226 uint64_t r_out[2]) {
227 const uint8_t *data = (const uint8_t *) key;
228 const int nblocks = len / 16;
229
230 uint64_t h1 = seed;
231 uint64_t h2 = seed;
232
233 const uint64_t c1 = KQU(0x87c37b91114253d5);
234 const uint64_t c2 = KQU(0x4cf5ad432745937f);
235
236 /* body */
237 {
238 const uint64_t *blocks = (const uint64_t *) (data);
239 int i;
240
241 for (i = 0; i < nblocks; i++) {
242 uint64_t k1 = hash_get_block_64(blocks, i*2 + 0);
243 uint64_t k2 = hash_get_block_64(blocks, i*2 + 1);
244
245 k1 *= c1; k1 = hash_rotl_64(k1, 31); k1 *= c2; h1 ^= k1;
246
247 h1 = hash_rotl_64(h1, 27); h1 += h2;
248 h1 = h1*5 + 0x52dce729;
249
250 k2 *= c2; k2 = hash_rotl_64(k2, 33); k2 *= c1; h2 ^= k2;
251
252 h2 = hash_rotl_64(h2, 31); h2 += h1;
253 h2 = h2*5 + 0x38495ab5;
254 }
255 }
256
257 /* tail */
258 {
259 const uint8_t *tail = (const uint8_t*)(data + nblocks*16);
260 uint64_t k1 = 0;
261 uint64_t k2 = 0;
262
263 switch (len & 15) {
264 case 15: k2 ^= ((uint64_t)(tail[14])) << 48; JEMALLOC_FALLTHROUGH
265 case 14: k2 ^= ((uint64_t)(tail[13])) << 40; JEMALLOC_FALLTHROUGH
266 case 13: k2 ^= ((uint64_t)(tail[12])) << 32; JEMALLOC_FALLTHROUGH
267 case 12: k2 ^= ((uint64_t)(tail[11])) << 24; JEMALLOC_FALLTHROUGH
268 case 11: k2 ^= ((uint64_t)(tail[10])) << 16; JEMALLOC_FALLTHROUGH
269 case 10: k2 ^= ((uint64_t)(tail[ 9])) << 8; JEMALLOC_FALLTHROUGH
270 case 9: k2 ^= ((uint64_t)(tail[ 8])) << 0;
271 k2 *= c2; k2 = hash_rotl_64(k2, 33); k2 *= c1; h2 ^= k2;
272 JEMALLOC_FALLTHROUGH
273 case 8: k1 ^= ((uint64_t)(tail[ 7])) << 56; JEMALLOC_FALLTHROUGH
274 case 7: k1 ^= ((uint64_t)(tail[ 6])) << 48; JEMALLOC_FALLTHROUGH
275 case 6: k1 ^= ((uint64_t)(tail[ 5])) << 40; JEMALLOC_FALLTHROUGH
276 case 5: k1 ^= ((uint64_t)(tail[ 4])) << 32; JEMALLOC_FALLTHROUGH
277 case 4: k1 ^= ((uint64_t)(tail[ 3])) << 24; JEMALLOC_FALLTHROUGH
278 case 3: k1 ^= ((uint64_t)(tail[ 2])) << 16; JEMALLOC_FALLTHROUGH
279 case 2: k1 ^= ((uint64_t)(tail[ 1])) << 8; JEMALLOC_FALLTHROUGH
280 case 1: k1 ^= ((uint64_t)(tail[ 0])) << 0;
281 k1 *= c1; k1 = hash_rotl_64(k1, 31); k1 *= c2; h1 ^= k1;
282 }
283 }
284
285 /* finalization */
286 h1 ^= len; h2 ^= len;
287
288 h1 += h2;
289 h2 += h1;
290
291 h1 = hash_fmix_64(h1);
292 h2 = hash_fmix_64(h2);
293
294 h1 += h2;
295 h2 += h1;
296
297 r_out[0] = h1;
298 r_out[1] = h2;
299 }
300
301 /******************************************************************************/
302 /* API. */
303 static inline void
hash(const void * key,size_t len,const uint32_t seed,size_t r_hash[2])304 hash(const void *key, size_t len, const uint32_t seed, size_t r_hash[2]) {
305 assert(len <= INT_MAX); /* Unfortunate implementation limitation. */
306
307 #if (LG_SIZEOF_PTR == 3 && !defined(JEMALLOC_BIG_ENDIAN))
308 hash_x64_128(key, (int)len, seed, (uint64_t *)r_hash);
309 #else
310 {
311 uint64_t hashes[2];
312 hash_x86_128(key, (int)len, seed, hashes);
313 r_hash[0] = (size_t)hashes[0];
314 r_hash[1] = (size_t)hashes[1];
315 }
316 #endif
317 }
318
319 #endif /* JEMALLOC_INTERNAL_HASH_H */
320