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t6101: make hash size independent
[git.git] / khash.h
blob21c2095216cb5dcb8be372d82443a8dd1c1435c8
1 /* The MIT License
2
3 Copyright (c) 2008, 2009, 2011 by Attractive Chaos <attractor@live.co.uk>
4
5 Permission is hereby granted, free of charge, to any person obtaining
6 a copy of this software and associated documentation files (the
7 "Software"), to deal in the Software without restriction, including
8 without limitation the rights to use, copy, modify, merge, publish,
9 distribute, sublicense, and/or sell copies of the Software, and to
10 permit persons to whom the Software is furnished to do so, subject to
11 the following conditions:
12
13 The above copyright notice and this permission notice shall be
14 included in all copies or substantial portions of the Software.
15
16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
20 BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
21 ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
22 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23 SOFTWARE.
24 */
25
26 #ifndef __AC_KHASH_H
27 #define __AC_KHASH_H
28
29 #include "cache.h"
30 #include "hashmap.h"
31
32 #define AC_VERSION_KHASH_H "0.2.8"
33
34 typedef uint32_t khint32_t;
35 typedef uint64_t khint64_t;
36
37 typedef khint32_t khint_t;
38 typedef khint_t khiter_t;
39
40 #define __ac_isempty(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&2)
41 #define __ac_isdel(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&1)
42 #define __ac_iseither(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&3)
43 #define __ac_set_isdel_false(flag, i) (flag[i>>4]&=~(1ul<<((i&0xfU)<<1)))
44 #define __ac_set_isempty_false(flag, i) (flag[i>>4]&=~(2ul<<((i&0xfU)<<1)))
45 #define __ac_set_isboth_false(flag, i) (flag[i>>4]&=~(3ul<<((i&0xfU)<<1)))
46 #define __ac_set_isdel_true(flag, i) (flag[i>>4]|=1ul<<((i&0xfU)<<1))
47
48 #define __ac_fsize(m) ((m) < 16? 1 : (m)>>4)
49
50 #define kroundup32(x) (--(x), (x)|=(x)>>1, (x)|=(x)>>2, (x)|=(x)>>4, (x)|=(x)>>8, (x)|=(x)>>16, ++(x))
51
52 static inline khint_t __ac_X31_hash_string(const char *s)
53 {
54 khint_t h = (khint_t)*s;
55 if (h) for (++s ; *s; ++s) h = (h << 5) - h + (khint_t)*s;
56 return h;
57 }
58
59 #define kh_str_hash_func(key) __ac_X31_hash_string(key)
60 #define kh_str_hash_equal(a, b) (strcmp(a, b) == 0)
61
62 static const double __ac_HASH_UPPER = 0.77;
63
64 #define __KHASH_TYPE(name, khkey_t, khval_t) \
65 typedef struct { \
66 khint_t n_buckets, size, n_occupied, upper_bound; \
67 khint32_t *flags; \
68 khkey_t *keys; \
69 khval_t *vals; \
70 } kh_##name##_t;
71
72 #define __KHASH_PROTOTYPES(name, khkey_t, khval_t) \
73 kh_##name##_t *kh_init_##name(void); \
74 void kh_destroy_##name(kh_##name##_t *h); \
75 void kh_clear_##name(kh_##name##_t *h); \
76 khint_t kh_get_##name(const kh_##name##_t *h, khkey_t key); \
77 int kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets); \
78 khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret); \
79 void kh_del_##name(kh_##name##_t *h, khint_t x);
80
81 #define __KHASH_IMPL(name, SCOPE, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
82 SCOPE kh_##name##_t *kh_init_##name(void) { \
83 return (kh_##name##_t*)xcalloc(1, sizeof(kh_##name##_t)); \
84 } \
85 SCOPE void kh_release_##name(kh_##name##_t *h) \
86 { \
87 free(h->flags); \
88 free((void *)h->keys); \
89 free((void *)h->vals); \
90 } \
91 SCOPE void kh_destroy_##name(kh_##name##_t *h) \
92 { \
93 if (h) { \
94 kh_release_##name(h); \
95 free(h); \
96 } \
97 } \
98 SCOPE void kh_clear_##name(kh_##name##_t *h) \
99 { \
100 if (h && h->flags) { \
101 memset(h->flags, 0xaa, __ac_fsize(h->n_buckets) * sizeof(khint32_t)); \
102 h->size = h->n_occupied = 0; \
103 } \
104 } \
105 SCOPE khint_t kh_get_##name(const kh_##name##_t *h, khkey_t key) \
106 { \
107 if (h->n_buckets) { \
108 khint_t k, i, last, mask, step = 0; \
109 mask = h->n_buckets - 1; \
110 k = __hash_func(key); i = k & mask; \
111 last = i; \
112 while (!__ac_isempty(h->flags, i) && (__ac_isdel(h->flags, i) || !__hash_equal(h->keys[i], key))) { \
113 i = (i + (++step)) & mask; \
114 if (i == last) return h->n_buckets; \
115 } \
116 return __ac_iseither(h->flags, i)? h->n_buckets : i; \
117 } else return 0; \
118 } \
119 SCOPE int kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets) \
120 { /* This function uses 0.25*n_buckets bytes of working space instead of [sizeof(key_t+val_t)+.25]*n_buckets. */ \
121 khint32_t *new_flags = NULL; \
122 khint_t j = 1; \
123 { \
124 kroundup32(new_n_buckets); \
125 if (new_n_buckets < 4) new_n_buckets = 4; \
126 if (h->size >= (khint_t)(new_n_buckets * __ac_HASH_UPPER + 0.5)) j = 0; /* requested size is too small */ \
127 else { /* hash table size to be changed (shrink or expand); rehash */ \
128 ALLOC_ARRAY(new_flags, __ac_fsize(new_n_buckets)); \
129 if (!new_flags) return -1; \
130 memset(new_flags, 0xaa, __ac_fsize(new_n_buckets) * sizeof(khint32_t)); \
131 if (h->n_buckets < new_n_buckets) { /* expand */ \
132 REALLOC_ARRAY(h->keys, new_n_buckets); \
133 if (kh_is_map) { \
134 REALLOC_ARRAY(h->vals, new_n_buckets); \
135 } \
136 } /* otherwise shrink */ \
137 } \
138 } \
139 if (j) { /* rehashing is needed */ \
140 for (j = 0; j != h->n_buckets; ++j) { \
141 if (__ac_iseither(h->flags, j) == 0) { \
142 khkey_t key = h->keys[j]; \
143 khval_t val; \
144 khint_t new_mask; \
145 new_mask = new_n_buckets - 1; \
146 if (kh_is_map) val = h->vals[j]; \
147 __ac_set_isdel_true(h->flags, j); \
148 while (1) { /* kick-out process; sort of like in Cuckoo hashing */ \
149 khint_t k, i, step = 0; \
150 k = __hash_func(key); \
151 i = k & new_mask; \
152 while (!__ac_isempty(new_flags, i)) i = (i + (++step)) & new_mask; \
153 __ac_set_isempty_false(new_flags, i); \
154 if (i < h->n_buckets && __ac_iseither(h->flags, i) == 0) { /* kick out the existing element */ \
155 { khkey_t tmp = h->keys[i]; h->keys[i] = key; key = tmp; } \
156 if (kh_is_map) { khval_t tmp = h->vals[i]; h->vals[i] = val; val = tmp; } \
157 __ac_set_isdel_true(h->flags, i); /* mark it as deleted in the old hash table */ \
158 } else { /* write the element and jump out of the loop */ \
159 h->keys[i] = key; \
160 if (kh_is_map) h->vals[i] = val; \
161 break; \
162 } \
163 } \
164 } \
165 } \
166 if (h->n_buckets > new_n_buckets) { /* shrink the hash table */ \
167 REALLOC_ARRAY(h->keys, new_n_buckets); \
168 if (kh_is_map) REALLOC_ARRAY(h->vals, new_n_buckets); \
169 } \
170 free(h->flags); /* free the working space */ \
171 h->flags = new_flags; \
172 h->n_buckets = new_n_buckets; \
173 h->n_occupied = h->size; \
174 h->upper_bound = (khint_t)(h->n_buckets * __ac_HASH_UPPER + 0.5); \
175 } \
176 return 0; \
177 } \
178 SCOPE khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret) \
179 { \
180 khint_t x; \
181 if (h->n_occupied >= h->upper_bound) { /* update the hash table */ \
182 if (h->n_buckets > (h->size<<1)) { \
183 if (kh_resize_##name(h, h->n_buckets - 1) < 0) { /* clear "deleted" elements */ \
184 *ret = -1; return h->n_buckets; \
185 } \
186 } else if (kh_resize_##name(h, h->n_buckets + 1) < 0) { /* expand the hash table */ \
187 *ret = -1; return h->n_buckets; \
188 } \
189 } /* TODO: to implement automatically shrinking; resize() already support shrinking */ \
190 { \
191 khint_t k, i, site, last, mask = h->n_buckets - 1, step = 0; \
192 x = site = h->n_buckets; k = __hash_func(key); i = k & mask; \
193 if (__ac_isempty(h->flags, i)) x = i; /* for speed up */ \
194 else { \
195 last = i; \
196 while (!__ac_isempty(h->flags, i) && (__ac_isdel(h->flags, i) || !__hash_equal(h->keys[i], key))) { \
197 if (__ac_isdel(h->flags, i)) site = i; \
198 i = (i + (++step)) & mask; \
199 if (i == last) { x = site; break; } \
200 } \
201 if (x == h->n_buckets) { \
202 if (__ac_isempty(h->flags, i) && site != h->n_buckets) x = site; \
203 else x = i; \
204 } \
205 } \
206 } \
207 if (__ac_isempty(h->flags, x)) { /* not present at all */ \
208 h->keys[x] = key; \
209 __ac_set_isboth_false(h->flags, x); \
210 ++h->size; ++h->n_occupied; \
211 *ret = 1; \
212 } else if (__ac_isdel(h->flags, x)) { /* deleted */ \
213 h->keys[x] = key; \
214 __ac_set_isboth_false(h->flags, x); \
215 ++h->size; \
216 *ret = 2; \
217 } else *ret = 0; /* Don't touch h->keys[x] if present and not deleted */ \
218 return x; \
219 } \
220 SCOPE void kh_del_##name(kh_##name##_t *h, khint_t x) \
221 { \
222 if (x != h->n_buckets && !__ac_iseither(h->flags, x)) { \
223 __ac_set_isdel_true(h->flags, x); \
224 --h->size; \
225 } \
226 }
227
228 #define KHASH_DECLARE(name, khkey_t, khval_t) \
229 __KHASH_TYPE(name, khkey_t, khval_t) \
230 __KHASH_PROTOTYPES(name, khkey_t, khval_t)
231
232 #define KHASH_INIT2(name, SCOPE, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
233 __KHASH_TYPE(name, khkey_t, khval_t) \
234 __KHASH_IMPL(name, SCOPE, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal)
235
236 #define KHASH_INIT(name, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
237 KHASH_INIT2(name, MAYBE_UNUSED static inline, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal)
238
239 /* Other convenient macros... */
240
241 /*! @function
242 @abstract Test whether a bucket contains data.
243 @param h Pointer to the hash table [khash_t(name)*]
244 @param x Iterator to the bucket [khint_t]
245 @return 1 if containing data; 0 otherwise [int]
246 */
247 #define kh_exist(h, x) (!__ac_iseither((h)->flags, (x)))
248
249 /*! @function
250 @abstract Get key given an iterator
251 @param h Pointer to the hash table [khash_t(name)*]
252 @param x Iterator to the bucket [khint_t]
253 @return Key [type of keys]
254 */
255 #define kh_key(h, x) ((h)->keys[x])
256
257 /*! @function
258 @abstract Get value given an iterator
259 @param h Pointer to the hash table [khash_t(name)*]
260 @param x Iterator to the bucket [khint_t]
261 @return Value [type of values]
262 @discussion For hash sets, calling this results in segfault.
263 */
264 #define kh_val(h, x) ((h)->vals[x])
265
266 /*! @function
267 @abstract Alias of kh_val()
268 */
269 #define kh_value(h, x) ((h)->vals[x])
270
271 /*! @function
272 @abstract Get the start iterator
273 @param h Pointer to the hash table [khash_t(name)*]
274 @return The start iterator [khint_t]
275 */
276 #define kh_begin(h) (khint_t)(0)
277
278 /*! @function
279 @abstract Get the end iterator
280 @param h Pointer to the hash table [khash_t(name)*]
281 @return The end iterator [khint_t]
282 */
283 #define kh_end(h) ((h)->n_buckets)
284
285 /*! @function
286 @abstract Get the number of elements in the hash table
287 @param h Pointer to the hash table [khash_t(name)*]
288 @return Number of elements in the hash table [khint_t]
289 */
290 #define kh_size(h) ((h)->size)
291
292 /*! @function
293 @abstract Get the number of buckets in the hash table
294 @param h Pointer to the hash table [khash_t(name)*]
295 @return Number of buckets in the hash table [khint_t]
296 */
297 #define kh_n_buckets(h) ((h)->n_buckets)
298
299 /*! @function
300 @abstract Iterate over the entries in the hash table
301 @param h Pointer to the hash table [khash_t(name)*]
302 @param kvar Variable to which key will be assigned
303 @param vvar Variable to which value will be assigned
304 @param code Block of code to execute
305 */
306 #define kh_foreach(h, kvar, vvar, code) { khint_t __i; \
307 for (__i = kh_begin(h); __i != kh_end(h); ++__i) { \
308 if (!kh_exist(h,__i)) continue; \
309 (kvar) = kh_key(h,__i); \
310 (vvar) = kh_val(h,__i); \
311 code; \
312 } }
313
314 /*! @function
315 @abstract Iterate over the values in the hash table
316 @param h Pointer to the hash table [khash_t(name)*]
317 @param vvar Variable to which value will be assigned
318 @param code Block of code to execute
319 */
320 #define kh_foreach_value(h, vvar, code) { khint_t __i; \
321 for (__i = kh_begin(h); __i != kh_end(h); ++__i) { \
322 if (!kh_exist(h,__i)) continue; \
323 (vvar) = kh_val(h,__i); \
324 code; \
325 } }
326
327 static inline unsigned int oidhash_by_value(struct object_id oid)
328 {
329 return oidhash(&oid);
330 }
331
332 static inline int oideq_by_value(struct object_id a, struct object_id b)
333 {
334 return oideq(&a, &b);
335 }
336
337 KHASH_INIT(oid_set, struct object_id, int, 0, oidhash_by_value, oideq_by_value)
338
339 KHASH_INIT(oid_map, struct object_id, void *, 1, oidhash_by_value, oideq_by_value)
340
341 KHASH_INIT(oid_pos, struct object_id, int, 1, oidhash_by_value, oideq_by_value)
342
343 #endif /* __AC_KHASH_H */
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