1 /**************************************************************************
2 *
3 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28 /*
29 * Authors:
30 * Zack Rusin <zack@tungstengraphics.com>
31 */
32
33 #include "util/u_debug.h"
34 #include "util/u_memory.h"
35
36 #include "cso_hash.h"
37
38 #define MAX(a, b) ((a > b) ? (a) : (b))
39
40 static const int MinNumBits = 4;
41
42 static const unsigned char prime_deltas[] = {
43 0, 0, 1, 3, 1, 5, 3, 3, 1, 9, 7, 5, 3, 9, 25, 3,
44 1, 21, 3, 21, 7, 15, 9, 5, 3, 29, 15, 0, 0, 0, 0, 0
45 };
46
primeForNumBits(int numBits)47 static int primeForNumBits(int numBits)
48 {
49 return (1 << numBits) + prime_deltas[numBits];
50 }
51
52 /*
53 Returns the smallest integer n such that
54 primeForNumBits(n) >= hint.
55 */
countBits(int hint)56 static int countBits(int hint)
57 {
58 int numBits = 0;
59 int bits = hint;
60
61 while (bits > 1) {
62 bits >>= 1;
63 numBits++;
64 }
65
66 if (numBits >= (int)sizeof(prime_deltas)) {
67 numBits = sizeof(prime_deltas) - 1;
68 } else if (primeForNumBits(numBits) < hint) {
69 ++numBits;
70 }
71 return numBits;
72 }
73
74 struct cso_node {
75 struct cso_node *next;
76 unsigned key;
77 void *value;
78 };
79
80 struct cso_hash_data {
81 struct cso_node *fakeNext;
82 struct cso_node **buckets;
83 int size;
84 int nodeSize;
85 short userNumBits;
86 short numBits;
87 int numBuckets;
88 };
89
90 struct cso_hash {
91 union {
92 struct cso_hash_data *d;
93 struct cso_node *e;
94 } data;
95 };
96
cso_data_allocate_node(struct cso_hash_data * hash)97 static void *cso_data_allocate_node(struct cso_hash_data *hash)
98 {
99 return MALLOC(hash->nodeSize);
100 }
101
cso_free_node(struct cso_node * node)102 static void cso_free_node(struct cso_node *node)
103 {
104 FREE(node);
105 }
106
107 static struct cso_node *
cso_hash_create_node(struct cso_hash * hash,unsigned akey,void * avalue,struct cso_node ** anextNode)108 cso_hash_create_node(struct cso_hash *hash,
109 unsigned akey, void *avalue,
110 struct cso_node **anextNode)
111 {
112 struct cso_node *node = cso_data_allocate_node(hash->data.d);
113
114 if (!node)
115 return NULL;
116
117 node->key = akey;
118 node->value = avalue;
119
120 node->next = (struct cso_node*)(*anextNode);
121 *anextNode = node;
122 ++hash->data.d->size;
123 return node;
124 }
125
cso_data_rehash(struct cso_hash_data * hash,int hint)126 static void cso_data_rehash(struct cso_hash_data *hash, int hint)
127 {
128 if (hint < 0) {
129 hint = countBits(-hint);
130 if (hint < MinNumBits)
131 hint = MinNumBits;
132 hash->userNumBits = (short)hint;
133 while (primeForNumBits(hint) < (hash->size >> 1))
134 ++hint;
135 } else if (hint < MinNumBits) {
136 hint = MinNumBits;
137 }
138
139 if (hash->numBits != hint) {
140 struct cso_node *e = (struct cso_node *)(hash);
141 struct cso_node **oldBuckets = hash->buckets;
142 int oldNumBuckets = hash->numBuckets;
143 int i = 0;
144
145 hash->numBits = (short)hint;
146 hash->numBuckets = primeForNumBits(hint);
147 hash->buckets = MALLOC(sizeof(struct cso_node*) * hash->numBuckets);
148 for (i = 0; i < hash->numBuckets; ++i)
149 hash->buckets[i] = e;
150
151 for (i = 0; i < oldNumBuckets; ++i) {
152 struct cso_node *firstNode = oldBuckets[i];
153 while (firstNode != e) {
154 unsigned h = firstNode->key;
155 struct cso_node *lastNode = firstNode;
156 struct cso_node *afterLastNode;
157 struct cso_node **beforeFirstNode;
158
159 while (lastNode->next != e && lastNode->next->key == h)
160 lastNode = lastNode->next;
161
162 afterLastNode = lastNode->next;
163 beforeFirstNode = &hash->buckets[h % hash->numBuckets];
164 while (*beforeFirstNode != e)
165 beforeFirstNode = &(*beforeFirstNode)->next;
166 lastNode->next = *beforeFirstNode;
167 *beforeFirstNode = firstNode;
168 firstNode = afterLastNode;
169 }
170 }
171 FREE(oldBuckets);
172 }
173 }
174
cso_data_might_grow(struct cso_hash_data * hash)175 static void cso_data_might_grow(struct cso_hash_data *hash)
176 {
177 if (hash->size >= hash->numBuckets)
178 cso_data_rehash(hash, hash->numBits + 1);
179 }
180
cso_data_has_shrunk(struct cso_hash_data * hash)181 static void cso_data_has_shrunk(struct cso_hash_data *hash)
182 {
183 if (hash->size <= (hash->numBuckets >> 3) &&
184 hash->numBits > hash->userNumBits) {
185 int max = MAX(hash->numBits-2, hash->userNumBits);
186 cso_data_rehash(hash, max);
187 }
188 }
189
cso_data_first_node(struct cso_hash_data * hash)190 static struct cso_node *cso_data_first_node(struct cso_hash_data *hash)
191 {
192 struct cso_node *e = (struct cso_node *)(hash);
193 struct cso_node **bucket = hash->buckets;
194 int n = hash->numBuckets;
195 while (n--) {
196 if (*bucket != e)
197 return *bucket;
198 ++bucket;
199 }
200 return e;
201 }
202
cso_hash_find_node(struct cso_hash * hash,unsigned akey)203 static struct cso_node **cso_hash_find_node(struct cso_hash *hash, unsigned akey)
204 {
205 struct cso_node **node;
206
207 if (hash->data.d->numBuckets) {
208 node = (struct cso_node **)(&hash->data.d->buckets[akey % hash->data.d->numBuckets]);
209 assert(*node == hash->data.e || (*node)->next);
210 while (*node != hash->data.e && (*node)->key != akey)
211 node = &(*node)->next;
212 } else {
213 node = (struct cso_node **)((const struct cso_node * const *)(&hash->data.e));
214 }
215 return node;
216 }
217
cso_hash_insert(struct cso_hash * hash,unsigned key,void * data)218 struct cso_hash_iter cso_hash_insert(struct cso_hash *hash,
219 unsigned key, void *data)
220 {
221 cso_data_might_grow(hash->data.d);
222
223 {
224 struct cso_node **nextNode = cso_hash_find_node(hash, key);
225 struct cso_node *node = cso_hash_create_node(hash, key, data, nextNode);
226 if (!node) {
227 struct cso_hash_iter null_iter = {hash, 0};
228 return null_iter;
229 }
230
231 {
232 struct cso_hash_iter iter = {hash, node};
233 return iter;
234 }
235 }
236 }
237
cso_hash_create(void)238 struct cso_hash * cso_hash_create(void)
239 {
240 struct cso_hash *hash = MALLOC_STRUCT(cso_hash);
241 if (!hash)
242 return NULL;
243
244 hash->data.d = MALLOC_STRUCT(cso_hash_data);
245 if (!hash->data.d) {
246 FREE(hash);
247 return NULL;
248 }
249
250 hash->data.d->fakeNext = 0;
251 hash->data.d->buckets = 0;
252 hash->data.d->size = 0;
253 hash->data.d->nodeSize = sizeof(struct cso_node);
254 hash->data.d->userNumBits = (short)MinNumBits;
255 hash->data.d->numBits = 0;
256 hash->data.d->numBuckets = 0;
257
258 return hash;
259 }
260
cso_hash_delete(struct cso_hash * hash)261 void cso_hash_delete(struct cso_hash *hash)
262 {
263 struct cso_node *e_for_x = (struct cso_node *)(hash->data.d);
264 struct cso_node **bucket = (struct cso_node **)(hash->data.d->buckets);
265 int n = hash->data.d->numBuckets;
266 while (n--) {
267 struct cso_node *cur = *bucket++;
268 while (cur != e_for_x) {
269 struct cso_node *next = cur->next;
270 cso_free_node(cur);
271 cur = next;
272 }
273 }
274 FREE(hash->data.d->buckets);
275 FREE(hash->data.d);
276 FREE(hash);
277 }
278
cso_hash_find(struct cso_hash * hash,unsigned key)279 struct cso_hash_iter cso_hash_find(struct cso_hash *hash,
280 unsigned key)
281 {
282 struct cso_node **nextNode = cso_hash_find_node(hash, key);
283 struct cso_hash_iter iter = {hash, *nextNode};
284 return iter;
285 }
286
cso_hash_iter_key(struct cso_hash_iter iter)287 unsigned cso_hash_iter_key(struct cso_hash_iter iter)
288 {
289 if (!iter.node || iter.hash->data.e == iter.node)
290 return 0;
291 return iter.node->key;
292 }
293
cso_hash_iter_data(struct cso_hash_iter iter)294 void * cso_hash_iter_data(struct cso_hash_iter iter)
295 {
296 if (!iter.node || iter.hash->data.e == iter.node)
297 return 0;
298 return iter.node->value;
299 }
300
cso_hash_data_next(struct cso_node * node)301 static struct cso_node *cso_hash_data_next(struct cso_node *node)
302 {
303 union {
304 struct cso_node *next;
305 struct cso_node *e;
306 struct cso_hash_data *d;
307 } a;
308 int start;
309 struct cso_node **bucket;
310 int n;
311
312 a.next = node->next;
313 if (!a.next) {
314 debug_printf("iterating beyond the last element\n");
315 return 0;
316 }
317 if (a.next->next)
318 return a.next;
319
320 start = (node->key % a.d->numBuckets) + 1;
321 bucket = a.d->buckets + start;
322 n = a.d->numBuckets - start;
323 while (n--) {
324 if (*bucket != a.e)
325 return *bucket;
326 ++bucket;
327 }
328 return a.e;
329 }
330
331
cso_hash_data_prev(struct cso_node * node)332 static struct cso_node *cso_hash_data_prev(struct cso_node *node)
333 {
334 union {
335 struct cso_node *e;
336 struct cso_hash_data *d;
337 } a;
338 int start;
339 struct cso_node *sentinel;
340 struct cso_node **bucket;
341
342 a.e = node;
343 while (a.e->next)
344 a.e = a.e->next;
345
346 if (node == a.e)
347 start = a.d->numBuckets - 1;
348 else
349 start = node->key % a.d->numBuckets;
350
351 sentinel = node;
352 bucket = a.d->buckets + start;
353 while (start >= 0) {
354 if (*bucket != sentinel) {
355 struct cso_node *prev = *bucket;
356 while (prev->next != sentinel)
357 prev = prev->next;
358 return prev;
359 }
360
361 sentinel = a.e;
362 --bucket;
363 --start;
364 }
365 debug_printf("iterating backward beyond first element\n");
366 return a.e;
367 }
368
cso_hash_iter_next(struct cso_hash_iter iter)369 struct cso_hash_iter cso_hash_iter_next(struct cso_hash_iter iter)
370 {
371 struct cso_hash_iter next = {iter.hash, cso_hash_data_next(iter.node)};
372 return next;
373 }
374
cso_hash_iter_is_null(struct cso_hash_iter iter)375 int cso_hash_iter_is_null(struct cso_hash_iter iter)
376 {
377 if (!iter.node || iter.node == iter.hash->data.e)
378 return 1;
379 return 0;
380 }
381
cso_hash_take(struct cso_hash * hash,unsigned akey)382 void * cso_hash_take(struct cso_hash *hash,
383 unsigned akey)
384 {
385 struct cso_node **node = cso_hash_find_node(hash, akey);
386 if (*node != hash->data.e) {
387 void *t = (*node)->value;
388 struct cso_node *next = (*node)->next;
389 cso_free_node(*node);
390 *node = next;
391 --hash->data.d->size;
392 cso_data_has_shrunk(hash->data.d);
393 return t;
394 }
395 return 0;
396 }
397
cso_hash_iter_prev(struct cso_hash_iter iter)398 struct cso_hash_iter cso_hash_iter_prev(struct cso_hash_iter iter)
399 {
400 struct cso_hash_iter prev = {iter.hash,
401 cso_hash_data_prev(iter.node)};
402 return prev;
403 }
404
cso_hash_first_node(struct cso_hash * hash)405 struct cso_hash_iter cso_hash_first_node(struct cso_hash *hash)
406 {
407 struct cso_hash_iter iter = {hash, cso_data_first_node(hash->data.d)};
408 return iter;
409 }
410
cso_hash_size(struct cso_hash * hash)411 int cso_hash_size(struct cso_hash *hash)
412 {
413 return hash->data.d->size;
414 }
415
cso_hash_erase(struct cso_hash * hash,struct cso_hash_iter iter)416 struct cso_hash_iter cso_hash_erase(struct cso_hash *hash, struct cso_hash_iter iter)
417 {
418 struct cso_hash_iter ret = iter;
419 struct cso_node *node = iter.node;
420 struct cso_node **node_ptr;
421
422 if (node == hash->data.e)
423 return iter;
424
425 ret = cso_hash_iter_next(ret);
426 node_ptr = (struct cso_node**)(&hash->data.d->buckets[node->key % hash->data.d->numBuckets]);
427 while (*node_ptr != node)
428 node_ptr = &(*node_ptr)->next;
429 *node_ptr = node->next;
430 cso_free_node(node);
431 --hash->data.d->size;
432 return ret;
433 }
434
cso_hash_contains(struct cso_hash * hash,unsigned key)435 boolean cso_hash_contains(struct cso_hash *hash, unsigned key)
436 {
437 struct cso_node **node = cso_hash_find_node(hash, key);
438 return (*node != hash->data.e);
439 }
440