Mercurial > vim
annotate src/hashtab.c @ 31792:5369ce341633 v9.0.1228
patch 9.0.1228: fuzzy menu completion is only tested in the GUI
Commit: https://github.com/vim/vim/commit/145a6afe3a4be54689af5233710c85346ba1e5da
Author: zeertzjq <zeertzjq@outlook.com>
Date: Sun Jan 22 12:41:55 2023 +0000
patch 9.0.1228: fuzzy menu completion is only tested in the GUI
Problem: Fuzzy menu completion is only tested in the GUI.
Solution: Make fuzzy menu completion test work without GUI.
(closes #11861)
author | Bram Moolenaar <Bram@vim.org> |
---|---|
date | Sun, 22 Jan 2023 13:45:04 +0100 |
parents | 8b9771b827c1 |
children | 04d9dff67d99 |
rev | line source |
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1 /* vi:set ts=8 sts=4 sw=4 noet: |
799 | 2 * |
3 * VIM - Vi IMproved by Bram Moolenaar | |
4 * | |
5 * Do ":help uganda" in Vim to read copying and usage conditions. | |
6 * Do ":help credits" in Vim to see a list of people who contributed. | |
7 * See README.txt for an overview of the Vim source code. | |
8 */ | |
9 | |
10 /* | |
11 * hashtab.c: Handling of a hashtable with Vim-specific properties. | |
12 * | |
13 * Each item in a hashtable has a NUL terminated string key. A key can appear | |
14 * only once in the table. | |
15 * | |
16 * A hash number is computed from the key for quick lookup. When the hashes | |
17 * of two different keys point to the same entry an algorithm is used to | |
18 * iterate over other entries in the table until the right one is found. | |
19 * To make the iteration work removed keys are different from entries where a | |
20 * key was never present. | |
21 * | |
22 * The mechanism has been partly based on how Python Dictionaries are | |
23 * implemented. The algorithm is from Knuth Vol. 3, Sec. 6.4. | |
24 * | |
25 * The hashtable grows to accommodate more entries when needed. At least 1/3 | |
26 * of the entries is empty to keep the lookup efficient (at the cost of extra | |
27 * memory). | |
28 */ | |
29 | |
30 #include "vim.h" | |
31 | |
32 #if 0 | |
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33 # define HT_DEBUG // extra checks for table consistency and statistics |
799 | 34 |
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35 static long hash_count_lookup = 0; // count number of hashtab lookups |
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36 static long hash_count_perturb = 0; // count number of "misses" |
799 | 37 #endif |
38 | |
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39 // Magic value for algorithm that walks through the array. |
799 | 40 #define PERTURB_SHIFT 5 |
41 | |
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42 static int hash_may_resize(hashtab_T *ht, int minitems); |
799 | 43 |
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44 #if 0 // currently not used |
799 | 45 /* |
46 * Create an empty hash table. | |
47 * Returns NULL when out of memory. | |
48 */ | |
49 hashtab_T * | |
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50 hash_create(void) |
799 | 51 { |
52 hashtab_T *ht; | |
53 | |
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54 ht = ALLOC_ONE(hashtab_T); |
799 | 55 if (ht != NULL) |
56 hash_init(ht); | |
57 return ht; | |
58 } | |
59 #endif | |
60 | |
61 /* | |
62 * Initialize an empty hash table. | |
63 */ | |
64 void | |
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65 hash_init(hashtab_T *ht) |
799 | 66 { |
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67 // This zeroes all "ht_" entries and all the "hi_key" in "ht_smallarray". |
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68 CLEAR_POINTER(ht); |
799 | 69 ht->ht_array = ht->ht_smallarray; |
70 ht->ht_mask = HT_INIT_SIZE - 1; | |
71 } | |
72 | |
73 /* | |
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74 * If "ht->ht_flags" has HTFLAGS_FROZEN then give an error message using |
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75 * "command" and return TRUE. |
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76 */ |
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77 int |
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78 check_hashtab_frozen(hashtab_T *ht, char *command) |
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79 { |
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80 if ((ht->ht_flags & HTFLAGS_FROZEN) == 0) |
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81 return FALSE; |
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82 |
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83 semsg(_(e_not_allowed_to_add_or_remove_entries_str), command); |
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84 return TRUE; |
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85 } |
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86 |
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87 /* |
799 | 88 * Free the array of a hash table. Does not free the items it contains! |
89 * If "ht" is not freed then you should call hash_init() next! | |
90 */ | |
91 void | |
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92 hash_clear(hashtab_T *ht) |
799 | 93 { |
94 if (ht->ht_array != ht->ht_smallarray) | |
95 vim_free(ht->ht_array); | |
96 } | |
97 | |
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98 #if defined(FEAT_SPELL) || defined(FEAT_TERMINAL) || defined(PROTO) |
799 | 99 /* |
100 * Free the array of a hash table and all the keys it contains. The keys must | |
101 * have been allocated. "off" is the offset from the start of the allocate | |
102 * memory to the location of the key (it's always positive). | |
103 */ | |
104 void | |
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105 hash_clear_all(hashtab_T *ht, int off) |
799 | 106 { |
835 | 107 long todo; |
799 | 108 hashitem_T *hi; |
109 | |
835 | 110 todo = (long)ht->ht_used; |
799 | 111 for (hi = ht->ht_array; todo > 0; ++hi) |
112 { | |
113 if (!HASHITEM_EMPTY(hi)) | |
114 { | |
115 vim_free(hi->hi_key - off); | |
116 --todo; | |
117 } | |
118 } | |
119 hash_clear(ht); | |
120 } | |
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121 #endif |
799 | 122 |
123 /* | |
124 * Find "key" in hashtable "ht". "key" must not be NULL. | |
125 * Always returns a pointer to a hashitem. If the item was not found then | |
126 * HASHITEM_EMPTY() is TRUE. The pointer is then the place where the key | |
127 * would be added. | |
128 * WARNING: The returned pointer becomes invalid when the hashtable is changed | |
129 * (adding, setting or removing an item)! | |
130 */ | |
131 hashitem_T * | |
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132 hash_find(hashtab_T *ht, char_u *key) |
799 | 133 { |
134 return hash_lookup(ht, key, hash_hash(key)); | |
135 } | |
136 | |
137 /* | |
138 * Like hash_find(), but caller computes "hash". | |
139 */ | |
140 hashitem_T * | |
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141 hash_lookup(hashtab_T *ht, char_u *key, hash_T hash) |
799 | 142 { |
143 hash_T perturb; | |
144 hashitem_T *freeitem; | |
145 hashitem_T *hi; | |
3970 | 146 unsigned idx; |
799 | 147 |
148 #ifdef HT_DEBUG | |
149 ++hash_count_lookup; | |
150 #endif | |
151 | |
152 /* | |
153 * Quickly handle the most common situations: | |
154 * - return if there is no item at all | |
155 * - skip over a removed item | |
156 * - return if the item matches | |
157 */ | |
3970 | 158 idx = (unsigned)(hash & ht->ht_mask); |
799 | 159 hi = &ht->ht_array[idx]; |
160 | |
161 if (hi->hi_key == NULL) | |
162 return hi; | |
163 if (hi->hi_key == HI_KEY_REMOVED) | |
164 freeitem = hi; | |
165 else if (hi->hi_hash == hash && STRCMP(hi->hi_key, key) == 0) | |
166 return hi; | |
167 else | |
168 freeitem = NULL; | |
169 | |
170 /* | |
171 * Need to search through the table to find the key. The algorithm | |
172 * to step through the table starts with large steps, gradually becoming | |
173 * smaller down to (1/4 table size + 1). This means it goes through all | |
174 * table entries in the end. | |
175 * When we run into a NULL key it's clear that the key isn't there. | |
176 * Return the first available slot found (can be a slot of a removed | |
177 * item). | |
178 */ | |
179 for (perturb = hash; ; perturb >>= PERTURB_SHIFT) | |
180 { | |
181 #ifdef HT_DEBUG | |
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182 ++hash_count_perturb; // count a "miss" for hashtab lookup |
799 | 183 #endif |
3970 | 184 idx = (unsigned)((idx << 2U) + idx + perturb + 1U); |
799 | 185 hi = &ht->ht_array[idx & ht->ht_mask]; |
186 if (hi->hi_key == NULL) | |
187 return freeitem == NULL ? hi : freeitem; | |
188 if (hi->hi_hash == hash | |
189 && hi->hi_key != HI_KEY_REMOVED | |
190 && STRCMP(hi->hi_key, key) == 0) | |
191 return hi; | |
192 if (hi->hi_key == HI_KEY_REMOVED && freeitem == NULL) | |
193 freeitem = hi; | |
194 } | |
195 } | |
196 | |
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197 #if defined(FEAT_EVAL) || defined(FEAT_SYN_HL) || defined(PROTO) |
799 | 198 /* |
199 * Print the efficiency of hashtable lookups. | |
200 * Useful when trying different hash algorithms. | |
201 * Called when exiting. | |
202 */ | |
203 void | |
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204 hash_debug_results(void) |
799 | 205 { |
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206 # ifdef HT_DEBUG |
799 | 207 fprintf(stderr, "\r\n\r\n\r\n\r\n"); |
208 fprintf(stderr, "Number of hashtable lookups: %ld\r\n", hash_count_lookup); | |
209 fprintf(stderr, "Number of perturb loops: %ld\r\n", hash_count_perturb); | |
210 fprintf(stderr, "Percentage of perturb loops: %ld%%\r\n", | |
211 hash_count_perturb * 100 / hash_count_lookup); | |
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212 # endif |
799 | 213 } |
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214 #endif |
799 | 215 |
216 /* | |
217 * Add item with key "key" to hashtable "ht". | |
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218 * "command" is used for the error message when the hashtab if frozen. |
799 | 219 * Returns FAIL when out of memory or the key is already present. |
220 */ | |
221 int | |
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222 hash_add(hashtab_T *ht, char_u *key, char *command) |
799 | 223 { |
224 hash_T hash = hash_hash(key); | |
225 hashitem_T *hi; | |
226 | |
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227 if (check_hashtab_frozen(ht, command)) |
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228 return FAIL; |
799 | 229 hi = hash_lookup(ht, key, hash); |
230 if (!HASHITEM_EMPTY(hi)) | |
231 { | |
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232 internal_error("hash_add()"); |
799 | 233 return FAIL; |
234 } | |
235 return hash_add_item(ht, hi, key, hash); | |
236 } | |
237 | |
238 /* | |
239 * Add item "hi" with "key" to hashtable "ht". "key" must not be NULL and | |
240 * "hi" must have been obtained with hash_lookup() and point to an empty item. | |
241 * "hi" is invalid after this! | |
242 * Returns OK or FAIL (out of memory). | |
243 */ | |
244 int | |
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245 hash_add_item( |
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246 hashtab_T *ht, |
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247 hashitem_T *hi, |
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248 char_u *key, |
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249 hash_T hash) |
799 | 250 { |
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251 // If resizing failed before and it fails again we can't add an item. |
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252 if (ht->ht_flags & HTFLAGS_ERROR) |
799 | 253 return FAIL; |
254 | |
255 ++ht->ht_used; | |
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256 ++ht->ht_changed; |
799 | 257 if (hi->hi_key == NULL) |
258 ++ht->ht_filled; | |
259 hi->hi_key = key; | |
260 hi->hi_hash = hash; | |
261 | |
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262 // When the space gets low may resize the array. |
799 | 263 return hash_may_resize(ht, 0); |
264 } | |
265 | |
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266 #if 0 // not used |
799 | 267 /* |
268 * Overwrite hashtable item "hi" with "key". "hi" must point to the item that | |
269 * is to be overwritten. Thus the number of items in the hashtable doesn't | |
270 * change. | |
271 * Although the key must be identical, the pointer may be different, thus it's | |
272 * set anyway (the key is part of an item with that key). | |
273 * The caller must take care of freeing the old item. | |
274 * "hi" is invalid after this! | |
275 */ | |
276 void | |
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277 hash_set(hashitem_T *hi, char_u *key) |
799 | 278 { |
279 hi->hi_key = key; | |
280 } | |
281 #endif | |
282 | |
283 /* | |
284 * Remove item "hi" from hashtable "ht". "hi" must have been obtained with | |
285 * hash_lookup(). | |
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286 * "command" is used for the error message when the hashtab if frozen. |
799 | 287 * The caller must take care of freeing the item itself. |
288 */ | |
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289 int |
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290 hash_remove(hashtab_T *ht, hashitem_T *hi, char *command) |
799 | 291 { |
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292 if (check_hashtab_frozen(ht, command)) |
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293 return FAIL; |
799 | 294 --ht->ht_used; |
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295 ++ht->ht_changed; |
799 | 296 hi->hi_key = HI_KEY_REMOVED; |
297 hash_may_resize(ht, 0); | |
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298 return OK; |
799 | 299 } |
300 | |
301 /* | |
302 * Lock a hashtable: prevent that ht_array changes. | |
303 * Don't use this when items are to be added! | |
304 * Must call hash_unlock() later. | |
305 */ | |
306 void | |
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307 hash_lock(hashtab_T *ht) |
799 | 308 { |
309 ++ht->ht_locked; | |
310 } | |
311 | |
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312 #if defined(FEAT_PROP_POPUP) || defined(PROTO) |
799 | 313 /* |
314 * Lock a hashtable at the specified number of entries. | |
315 * Caller must make sure no more than "size" entries will be added. | |
316 * Must call hash_unlock() later. | |
317 */ | |
318 void | |
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319 hash_lock_size(hashtab_T *ht, int size) |
799 | 320 { |
321 (void)hash_may_resize(ht, size); | |
322 ++ht->ht_locked; | |
323 } | |
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324 #endif |
799 | 325 |
326 /* | |
327 * Unlock a hashtable: allow ht_array changes again. | |
328 * Table will be resized (shrink) when necessary. | |
329 * This must balance a call to hash_lock(). | |
330 */ | |
331 void | |
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332 hash_unlock(hashtab_T *ht) |
799 | 333 { |
334 --ht->ht_locked; | |
335 (void)hash_may_resize(ht, 0); | |
336 } | |
337 | |
338 /* | |
339 * Shrink a hashtable when there is too much empty space. | |
340 * Grow a hashtable when there is not enough empty space. | |
341 * Returns OK or FAIL (out of memory). | |
342 */ | |
343 static int | |
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344 hash_may_resize( |
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345 hashtab_T *ht, |
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346 int minitems) // minimal number of items |
799 | 347 { |
348 hashitem_T temparray[HT_INIT_SIZE]; | |
349 hashitem_T *oldarray, *newarray; | |
350 hashitem_T *olditem, *newitem; | |
3970 | 351 unsigned newi; |
799 | 352 int todo; |
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353 long_u newsize; |
799 | 354 long_u minsize; |
355 long_u newmask; | |
356 hash_T perturb; | |
357 | |
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358 // Don't resize a locked table. |
799 | 359 if (ht->ht_locked > 0) |
360 return OK; | |
361 | |
362 #ifdef HT_DEBUG | |
363 if (ht->ht_used > ht->ht_filled) | |
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364 emsg("hash_may_resize(): more used than filled"); |
799 | 365 if (ht->ht_filled >= ht->ht_mask + 1) |
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366 emsg("hash_may_resize(): table completely filled"); |
799 | 367 #endif |
368 | |
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369 long_u oldsize = ht->ht_mask + 1; |
799 | 370 if (minitems == 0) |
371 { | |
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372 // Return quickly for small tables with at least two NULL items. NULL |
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373 // items are required for the lookup to decide a key isn't there. |
799 | 374 if (ht->ht_filled < HT_INIT_SIZE - 1 |
375 && ht->ht_array == ht->ht_smallarray) | |
376 return OK; | |
377 | |
378 /* | |
379 * Grow or refill the array when it's more than 2/3 full (including | |
380 * removed items, so that they get cleaned up). | |
381 * Shrink the array when it's less than 1/5 full. When growing it is | |
382 * at least 1/4 full (avoids repeated grow-shrink operations) | |
383 */ | |
384 if (ht->ht_filled * 3 < oldsize * 2 && ht->ht_used > oldsize / 5) | |
385 return OK; | |
386 | |
387 if (ht->ht_used > 1000) | |
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388 minsize = ht->ht_used * 2; // it's big, don't make too much room |
799 | 389 else |
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390 minsize = ht->ht_used * 4; // make plenty of room |
799 | 391 } |
392 else | |
393 { | |
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394 // Use specified size. |
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395 if ((long_u)minitems < ht->ht_used) // just in case... |
835 | 396 minitems = (int)ht->ht_used; |
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397 minsize = (minitems * 3 + 1) / 2; // array is up to 2/3 full |
799 | 398 } |
399 | |
400 newsize = HT_INIT_SIZE; | |
401 while (newsize < minsize) | |
402 { | |
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403 newsize <<= 1; // make sure it's always a power of 2 |
799 | 404 if (newsize == 0) |
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405 return FAIL; // overflow |
799 | 406 } |
407 | |
408 if (newsize == HT_INIT_SIZE) | |
409 { | |
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410 // Use the small array inside the hashdict structure. |
799 | 411 newarray = ht->ht_smallarray; |
412 if (ht->ht_array == newarray) | |
413 { | |
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414 // Moving from ht_smallarray to ht_smallarray! Happens when there |
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415 // are many removed items. Copy the items to be able to clean up |
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416 // removed items. |
799 | 417 mch_memmove(temparray, newarray, sizeof(temparray)); |
418 oldarray = temparray; | |
419 } | |
420 else | |
421 oldarray = ht->ht_array; | |
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422 CLEAR_FIELD(ht->ht_smallarray); |
799 | 423 } |
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424 |
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425 else if (newsize == oldsize && ht->ht_filled * 3 < oldsize * 2) |
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426 { |
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427 // The hashtab is already at the desired size, and there are not too |
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428 // many removed items, bail out. |
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429 return OK; |
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430 } |
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431 |
799 | 432 else |
433 { | |
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434 // Allocate an array. |
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435 newarray = ALLOC_CLEAR_MULT(hashitem_T, newsize); |
799 | 436 if (newarray == NULL) |
437 { | |
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438 // Out of memory. When there are NULL items still return OK. |
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439 // Otherwise set ht_flags to HTFLAGS_ERROR, because lookup may |
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440 // result in a hang if we add another item. |
799 | 441 if (ht->ht_filled < ht->ht_mask) |
442 return OK; | |
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443 ht->ht_flags |= HTFLAGS_ERROR; |
799 | 444 return FAIL; |
445 } | |
446 oldarray = ht->ht_array; | |
447 } | |
448 | |
449 /* | |
450 * Move all the items from the old array to the new one, placing them in | |
451 * the right spot. The new array won't have any removed items, thus this | |
452 * is also a cleanup action. | |
453 */ | |
454 newmask = newsize - 1; | |
835 | 455 todo = (int)ht->ht_used; |
799 | 456 for (olditem = oldarray; todo > 0; ++olditem) |
457 if (!HASHITEM_EMPTY(olditem)) | |
458 { | |
459 /* | |
460 * The algorithm to find the spot to add the item is identical to | |
461 * the algorithm to find an item in hash_lookup(). But we only | |
462 * need to search for a NULL key, thus it's simpler. | |
463 */ | |
3970 | 464 newi = (unsigned)(olditem->hi_hash & newmask); |
799 | 465 newitem = &newarray[newi]; |
466 | |
467 if (newitem->hi_key != NULL) | |
468 for (perturb = olditem->hi_hash; ; perturb >>= PERTURB_SHIFT) | |
469 { | |
3970 | 470 newi = (unsigned)((newi << 2U) + newi + perturb + 1U); |
799 | 471 newitem = &newarray[newi & newmask]; |
472 if (newitem->hi_key == NULL) | |
473 break; | |
474 } | |
475 *newitem = *olditem; | |
476 --todo; | |
477 } | |
478 | |
479 if (ht->ht_array != ht->ht_smallarray) | |
480 vim_free(ht->ht_array); | |
481 ht->ht_array = newarray; | |
482 ht->ht_mask = newmask; | |
483 ht->ht_filled = ht->ht_used; | |
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484 ++ht->ht_changed; |
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485 ht->ht_flags &= ~HTFLAGS_ERROR; |
799 | 486 |
487 return OK; | |
488 } | |
489 | |
490 /* | |
491 * Get the hash number for a key. | |
492 * If you think you know a better hash function: Compile with HT_DEBUG set and | |
493 * run a script that uses hashtables a lot. Vim will then print statistics | |
494 * when exiting. Try that with the current hash algorithm and yours. The | |
495 * lower the percentage the better. | |
496 */ | |
497 hash_T | |
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498 hash_hash(char_u *key) |
799 | 499 { |
500 hash_T hash; | |
501 char_u *p; | |
502 | |
503 if ((hash = *key) == 0) | |
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504 return (hash_T)0; |
799 | 505 p = key + 1; |
506 | |
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507 // A simplistic algorithm that appears to do very well. |
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508 // Suggested by George Reilly. |
799 | 509 while (*p != NUL) |
510 hash = hash * 101 + *p++; | |
511 | |
512 return hash; | |
513 } |