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1 /*
2  * Copyright © 2009,2012 Intel Corporation
3  * Copyright © 1988-2004 Keith Packard and Bart Massey.
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining a
6  * copy of this software and associated documentation files (the "Software"),
7  * to deal in the Software without restriction, including without limitation
8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9  * and/or sell copies of the Software, and to permit persons to whom the
10  * Software is furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice (including the next
13  * paragraph) shall be included in all copies or substantial portions of the
14  * Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22  * IN THE SOFTWARE.
23  *
24  * Except as contained in this notice, the names of the authors
25  * or their institutions shall not be used in advertising or
26  * otherwise to promote the sale, use or other dealings in this
27  * Software without prior written authorization from the
28  * authors.
29  *
30  * Authors:
31  *    Eric Anholt <eric@anholt.net>
32  *    Keith Packard <keithp@keithp.com>
33  */
34 
35 /**
36  * Implements an open-addressing, linear-reprobing hash table.
37  *
38  * For more information, see:
39  *
40  * http://cgit.freedesktop.org/~anholt/hash_table/tree/README
41  */
42 
43 #include <stdlib.h>
44 #include <string.h>
45 #include <assert.h>
46 
47 #include "hash_table.h"
48 #include "ralloc.h"
49 #include "macros.h"
50 #include "u_memory.h"
51 #include "fast_urem_by_const.h"
52 #include "util/u_memory.h"
53 
54 #define XXH_INLINE_ALL
55 #include "xxhash.h"
56 
57 /**
58  * Magic number that gets stored outside of the struct hash_table.
59  *
60  * The hash table needs a particular pointer to be the marker for a key that
61  * was deleted from the table, along with NULL for the "never allocated in the
62  * table" marker.  Legacy GL allows any GLuint to be used as a GL object name,
63  * and we use a 1:1 mapping from GLuints to key pointers, so we need to be
64  * able to track a GLuint that happens to match the deleted key outside of
65  * struct hash_table.  We tell the hash table to use "1" as the deleted key
66  * value, so that we test the deleted-key-in-the-table path as best we can.
67  */
68 #define DELETED_KEY_VALUE 1
69 
70 static inline void *
uint_key(unsigned id)71 uint_key(unsigned id)
72 {
73    return (void *)(uintptr_t) id;
74 }
75 
76 static const uint32_t deleted_key_value;
77 
78 /**
79  * From Knuth -- a good choice for hash/rehash values is p, p-2 where
80  * p and p-2 are both prime.  These tables are sized to have an extra 10%
81  * free to avoid exponential performance degradation as the hash table fills
82  */
83 static const struct {
84    uint32_t max_entries, size, rehash;
85    uint64_t size_magic, rehash_magic;
86 } hash_sizes[] = {
87 #define ENTRY(max_entries, size, rehash) \
88    { max_entries, size, rehash, \
89       REMAINDER_MAGIC(size), REMAINDER_MAGIC(rehash) }
90 
91    ENTRY(2,            5,            3            ),
92    ENTRY(4,            7,            5            ),
93    ENTRY(8,            13,           11           ),
94    ENTRY(16,           19,           17           ),
95    ENTRY(32,           43,           41           ),
96    ENTRY(64,           73,           71           ),
97    ENTRY(128,          151,          149          ),
98    ENTRY(256,          283,          281          ),
99    ENTRY(512,          571,          569          ),
100    ENTRY(1024,         1153,         1151         ),
101    ENTRY(2048,         2269,         2267         ),
102    ENTRY(4096,         4519,         4517         ),
103    ENTRY(8192,         9013,         9011         ),
104    ENTRY(16384,        18043,        18041        ),
105    ENTRY(32768,        36109,        36107        ),
106    ENTRY(65536,        72091,        72089        ),
107    ENTRY(131072,       144409,       144407       ),
108    ENTRY(262144,       288361,       288359       ),
109    ENTRY(524288,       576883,       576881       ),
110    ENTRY(1048576,      1153459,      1153457      ),
111    ENTRY(2097152,      2307163,      2307161      ),
112    ENTRY(4194304,      4613893,      4613891      ),
113    ENTRY(8388608,      9227641,      9227639      ),
114    ENTRY(16777216,     18455029,     18455027     ),
115    ENTRY(33554432,     36911011,     36911009     ),
116    ENTRY(67108864,     73819861,     73819859     ),
117    ENTRY(134217728,    147639589,    147639587    ),
118    ENTRY(268435456,    295279081,    295279079    ),
119    ENTRY(536870912,    590559793,    590559791    ),
120    ENTRY(1073741824,   1181116273,   1181116271   ),
121    ENTRY(2147483648ul, 2362232233ul, 2362232231ul )
122 };
123 
124 ASSERTED static inline bool
key_pointer_is_reserved(const struct hash_table * ht,const void * key)125 key_pointer_is_reserved(const struct hash_table *ht, const void *key)
126 {
127    return key == NULL || key == ht->deleted_key;
128 }
129 
130 static int
entry_is_free(const struct hash_entry * entry)131 entry_is_free(const struct hash_entry *entry)
132 {
133    return entry->key == NULL;
134 }
135 
136 static int
entry_is_deleted(const struct hash_table * ht,struct hash_entry * entry)137 entry_is_deleted(const struct hash_table *ht, struct hash_entry *entry)
138 {
139    return entry->key == ht->deleted_key;
140 }
141 
142 static int
entry_is_present(const struct hash_table * ht,struct hash_entry * entry)143 entry_is_present(const struct hash_table *ht, struct hash_entry *entry)
144 {
145    return entry->key != NULL && entry->key != ht->deleted_key;
146 }
147 
148 bool
_mesa_hash_table_init(struct hash_table * ht,void * mem_ctx,uint32_t (* key_hash_function)(const void * key),bool (* key_equals_function)(const void * a,const void * b))149 _mesa_hash_table_init(struct hash_table *ht,
150                       void *mem_ctx,
151                       uint32_t (*key_hash_function)(const void *key),
152                       bool (*key_equals_function)(const void *a,
153                                                   const void *b))
154 {
155    ht->size_index = 0;
156    ht->size = hash_sizes[ht->size_index].size;
157    ht->rehash = hash_sizes[ht->size_index].rehash;
158    ht->size_magic = hash_sizes[ht->size_index].size_magic;
159    ht->rehash_magic = hash_sizes[ht->size_index].rehash_magic;
160    ht->max_entries = hash_sizes[ht->size_index].max_entries;
161    ht->key_hash_function = key_hash_function;
162    ht->key_equals_function = key_equals_function;
163    ht->table = rzalloc_array(mem_ctx, struct hash_entry, ht->size);
164    ht->entries = 0;
165    ht->deleted_entries = 0;
166    ht->deleted_key = &deleted_key_value;
167 
168    return ht->table != NULL;
169 }
170 
171 struct hash_table *
_mesa_hash_table_create(void * mem_ctx,uint32_t (* key_hash_function)(const void * key),bool (* key_equals_function)(const void * a,const void * b))172 _mesa_hash_table_create(void *mem_ctx,
173                         uint32_t (*key_hash_function)(const void *key),
174                         bool (*key_equals_function)(const void *a,
175                                                     const void *b))
176 {
177    struct hash_table *ht;
178 
179    /* mem_ctx is used to allocate the hash table, but the hash table is used
180     * to allocate all of the suballocations.
181     */
182    ht = ralloc(mem_ctx, struct hash_table);
183    if (ht == NULL)
184       return NULL;
185 
186    if (!_mesa_hash_table_init(ht, ht, key_hash_function, key_equals_function)) {
187       ralloc_free(ht);
188       return NULL;
189    }
190 
191    return ht;
192 }
193 
194 static uint32_t
key_u32_hash(const void * key)195 key_u32_hash(const void *key)
196 {
197    uint32_t u = (uint32_t)(uintptr_t)key;
198    return _mesa_hash_uint(&u);
199 }
200 
201 static bool
key_u32_equals(const void * a,const void * b)202 key_u32_equals(const void *a, const void *b)
203 {
204    return (uint32_t)(uintptr_t)a == (uint32_t)(uintptr_t)b;
205 }
206 
207 /* key == 0 and key == deleted_key are not allowed */
208 struct hash_table *
_mesa_hash_table_create_u32_keys(void * mem_ctx)209 _mesa_hash_table_create_u32_keys(void *mem_ctx)
210 {
211    return _mesa_hash_table_create(mem_ctx, key_u32_hash, key_u32_equals);
212 }
213 
214 struct hash_table *
_mesa_hash_table_clone(struct hash_table * src,void * dst_mem_ctx)215 _mesa_hash_table_clone(struct hash_table *src, void *dst_mem_ctx)
216 {
217    struct hash_table *ht;
218 
219    ht = ralloc(dst_mem_ctx, struct hash_table);
220    if (ht == NULL)
221       return NULL;
222 
223    memcpy(ht, src, sizeof(struct hash_table));
224 
225    ht->table = ralloc_array(ht, struct hash_entry, ht->size);
226    if (ht->table == NULL) {
227       ralloc_free(ht);
228       return NULL;
229    }
230 
231    memcpy(ht->table, src->table, ht->size * sizeof(struct hash_entry));
232 
233    return ht;
234 }
235 
236 /**
237  * Frees the given hash table.
238  *
239  * If delete_function is passed, it gets called on each entry present before
240  * freeing.
241  */
242 void
_mesa_hash_table_destroy(struct hash_table * ht,void (* delete_function)(struct hash_entry * entry))243 _mesa_hash_table_destroy(struct hash_table *ht,
244                          void (*delete_function)(struct hash_entry *entry))
245 {
246    if (!ht)
247       return;
248 
249    if (delete_function) {
250       hash_table_foreach(ht, entry) {
251          delete_function(entry);
252       }
253    }
254    ralloc_free(ht);
255 }
256 
257 static void
hash_table_clear_fast(struct hash_table * ht)258 hash_table_clear_fast(struct hash_table *ht)
259 {
260    memset(ht->table, 0, sizeof(struct hash_entry) * hash_sizes[ht->size_index].size);
261    ht->entries = ht->deleted_entries = 0;
262 }
263 
264 /**
265  * Deletes all entries of the given hash table without deleting the table
266  * itself or changing its structure.
267  *
268  * If delete_function is passed, it gets called on each entry present.
269  */
270 void
_mesa_hash_table_clear(struct hash_table * ht,void (* delete_function)(struct hash_entry * entry))271 _mesa_hash_table_clear(struct hash_table *ht,
272                        void (*delete_function)(struct hash_entry *entry))
273 {
274    if (!ht)
275       return;
276 
277    struct hash_entry *entry;
278 
279    if (delete_function) {
280       for (entry = ht->table; entry != ht->table + ht->size; entry++) {
281          if (entry_is_present(ht, entry))
282             delete_function(entry);
283 
284          entry->key = NULL;
285       }
286       ht->entries = 0;
287       ht->deleted_entries = 0;
288    } else
289       hash_table_clear_fast(ht);
290 }
291 
292 /** Sets the value of the key pointer used for deleted entries in the table.
293  *
294  * The assumption is that usually keys are actual pointers, so we use a
295  * default value of a pointer to an arbitrary piece of storage in the library.
296  * But in some cases a consumer wants to store some other sort of value in the
297  * table, like a uint32_t, in which case that pointer may conflict with one of
298  * their valid keys.  This lets that user select a safe value.
299  *
300  * This must be called before any keys are actually deleted from the table.
301  */
302 void
_mesa_hash_table_set_deleted_key(struct hash_table * ht,const void * deleted_key)303 _mesa_hash_table_set_deleted_key(struct hash_table *ht, const void *deleted_key)
304 {
305    ht->deleted_key = deleted_key;
306 }
307 
308 static struct hash_entry *
hash_table_search(struct hash_table * ht,uint32_t hash,const void * key)309 hash_table_search(struct hash_table *ht, uint32_t hash, const void *key)
310 {
311    assert(!key_pointer_is_reserved(ht, key));
312 
313    uint32_t size = ht->size;
314    uint32_t start_hash_address = util_fast_urem32(hash, size, ht->size_magic);
315    uint32_t double_hash = 1 + util_fast_urem32(hash, ht->rehash,
316                                                ht->rehash_magic);
317    uint32_t hash_address = start_hash_address;
318 
319    do {
320       struct hash_entry *entry = ht->table + hash_address;
321 
322       if (entry_is_free(entry)) {
323          return NULL;
324       } else if (entry_is_present(ht, entry) && entry->hash == hash) {
325          if (ht->key_equals_function(key, entry->key)) {
326             return entry;
327          }
328       }
329 
330       hash_address += double_hash;
331       if (hash_address >= size)
332          hash_address -= size;
333    } while (hash_address != start_hash_address);
334 
335    return NULL;
336 }
337 
338 /**
339  * Finds a hash table entry with the given key and hash of that key.
340  *
341  * Returns NULL if no entry is found.  Note that the data pointer may be
342  * modified by the user.
343  */
344 struct hash_entry *
_mesa_hash_table_search(struct hash_table * ht,const void * key)345 _mesa_hash_table_search(struct hash_table *ht, const void *key)
346 {
347    assert(ht->key_hash_function);
348    return hash_table_search(ht, ht->key_hash_function(key), key);
349 }
350 
351 struct hash_entry *
_mesa_hash_table_search_pre_hashed(struct hash_table * ht,uint32_t hash,const void * key)352 _mesa_hash_table_search_pre_hashed(struct hash_table *ht, uint32_t hash,
353                                   const void *key)
354 {
355    assert(ht->key_hash_function == NULL || hash == ht->key_hash_function(key));
356    return hash_table_search(ht, hash, key);
357 }
358 
359 static struct hash_entry *
360 hash_table_insert(struct hash_table *ht, uint32_t hash,
361                   const void *key, void *data);
362 
363 static void
hash_table_insert_rehash(struct hash_table * ht,uint32_t hash,const void * key,void * data)364 hash_table_insert_rehash(struct hash_table *ht, uint32_t hash,
365                          const void *key, void *data)
366 {
367    uint32_t size = ht->size;
368    uint32_t start_hash_address = util_fast_urem32(hash, size, ht->size_magic);
369    uint32_t double_hash = 1 + util_fast_urem32(hash, ht->rehash,
370                                                ht->rehash_magic);
371    uint32_t hash_address = start_hash_address;
372    do {
373       struct hash_entry *entry = ht->table + hash_address;
374 
375       if (likely(entry->key == NULL)) {
376          entry->hash = hash;
377          entry->key = key;
378          entry->data = data;
379          return;
380       }
381 
382       hash_address += double_hash;
383       if (hash_address >= size)
384          hash_address -= size;
385    } while (true);
386 }
387 
388 static void
_mesa_hash_table_rehash(struct hash_table * ht,unsigned new_size_index)389 _mesa_hash_table_rehash(struct hash_table *ht, unsigned new_size_index)
390 {
391    struct hash_table old_ht;
392    struct hash_entry *table;
393 
394    if (ht->size_index == new_size_index && ht->deleted_entries == ht->max_entries) {
395       hash_table_clear_fast(ht);
396       assert(!ht->entries);
397       return;
398    }
399 
400    if (new_size_index >= ARRAY_SIZE(hash_sizes))
401       return;
402 
403    table = rzalloc_array(ralloc_parent(ht->table), struct hash_entry,
404                          hash_sizes[new_size_index].size);
405    if (table == NULL)
406       return;
407 
408    old_ht = *ht;
409 
410    ht->table = table;
411    ht->size_index = new_size_index;
412    ht->size = hash_sizes[ht->size_index].size;
413    ht->rehash = hash_sizes[ht->size_index].rehash;
414    ht->size_magic = hash_sizes[ht->size_index].size_magic;
415    ht->rehash_magic = hash_sizes[ht->size_index].rehash_magic;
416    ht->max_entries = hash_sizes[ht->size_index].max_entries;
417    ht->entries = 0;
418    ht->deleted_entries = 0;
419 
420    hash_table_foreach(&old_ht, entry) {
421       hash_table_insert_rehash(ht, entry->hash, entry->key, entry->data);
422    }
423 
424    ht->entries = old_ht.entries;
425 
426    ralloc_free(old_ht.table);
427 }
428 
429 static struct hash_entry *
hash_table_insert(struct hash_table * ht,uint32_t hash,const void * key,void * data)430 hash_table_insert(struct hash_table *ht, uint32_t hash,
431                   const void *key, void *data)
432 {
433    struct hash_entry *available_entry = NULL;
434 
435    assert(!key_pointer_is_reserved(ht, key));
436 
437    if (ht->entries >= ht->max_entries) {
438       _mesa_hash_table_rehash(ht, ht->size_index + 1);
439    } else if (ht->deleted_entries + ht->entries >= ht->max_entries) {
440       _mesa_hash_table_rehash(ht, ht->size_index);
441    }
442 
443    uint32_t size = ht->size;
444    uint32_t start_hash_address = util_fast_urem32(hash, size, ht->size_magic);
445    uint32_t double_hash = 1 + util_fast_urem32(hash, ht->rehash,
446                                                ht->rehash_magic);
447    uint32_t hash_address = start_hash_address;
448    do {
449       struct hash_entry *entry = ht->table + hash_address;
450 
451       if (!entry_is_present(ht, entry)) {
452          /* Stash the first available entry we find */
453          if (available_entry == NULL)
454             available_entry = entry;
455          if (entry_is_free(entry))
456             break;
457       }
458 
459       /* Implement replacement when another insert happens
460        * with a matching key.  This is a relatively common
461        * feature of hash tables, with the alternative
462        * generally being "insert the new value as well, and
463        * return it first when the key is searched for".
464        *
465        * Note that the hash table doesn't have a delete
466        * callback.  If freeing of old data pointers is
467        * required to avoid memory leaks, perform a search
468        * before inserting.
469        */
470       if (!entry_is_deleted(ht, entry) &&
471           entry->hash == hash &&
472           ht->key_equals_function(key, entry->key)) {
473          entry->key = key;
474          entry->data = data;
475          return entry;
476       }
477 
478       hash_address += double_hash;
479       if (hash_address >= size)
480          hash_address -= size;
481    } while (hash_address != start_hash_address);
482 
483    if (available_entry) {
484       if (entry_is_deleted(ht, available_entry))
485          ht->deleted_entries--;
486       available_entry->hash = hash;
487       available_entry->key = key;
488       available_entry->data = data;
489       ht->entries++;
490       return available_entry;
491    }
492 
493    /* We could hit here if a required resize failed. An unchecked-malloc
494     * application could ignore this result.
495     */
496    return NULL;
497 }
498 
499 /**
500  * Inserts the key with the given hash into the table.
501  *
502  * Note that insertion may rearrange the table on a resize or rehash,
503  * so previously found hash_entries are no longer valid after this function.
504  */
505 struct hash_entry *
_mesa_hash_table_insert(struct hash_table * ht,const void * key,void * data)506 _mesa_hash_table_insert(struct hash_table *ht, const void *key, void *data)
507 {
508    assert(ht->key_hash_function);
509    return hash_table_insert(ht, ht->key_hash_function(key), key, data);
510 }
511 
512 struct hash_entry *
_mesa_hash_table_insert_pre_hashed(struct hash_table * ht,uint32_t hash,const void * key,void * data)513 _mesa_hash_table_insert_pre_hashed(struct hash_table *ht, uint32_t hash,
514                                    const void *key, void *data)
515 {
516    assert(ht->key_hash_function == NULL || hash == ht->key_hash_function(key));
517    return hash_table_insert(ht, hash, key, data);
518 }
519 
520 /**
521  * This function deletes the given hash table entry.
522  *
523  * Note that deletion doesn't otherwise modify the table, so an iteration over
524  * the table deleting entries is safe.
525  */
526 void
_mesa_hash_table_remove(struct hash_table * ht,struct hash_entry * entry)527 _mesa_hash_table_remove(struct hash_table *ht,
528                         struct hash_entry *entry)
529 {
530    if (!entry)
531       return;
532 
533    entry->key = ht->deleted_key;
534    ht->entries--;
535    ht->deleted_entries++;
536 }
537 
538 /**
539  * Removes the entry with the corresponding key, if exists.
540  */
_mesa_hash_table_remove_key(struct hash_table * ht,const void * key)541 void _mesa_hash_table_remove_key(struct hash_table *ht,
542                                  const void *key)
543 {
544    _mesa_hash_table_remove(ht, _mesa_hash_table_search(ht, key));
545 }
546 
547 /**
548  * This function is an iterator over the hash_table when no deleted entries are present.
549  *
550  * Pass in NULL for the first entry, as in the start of a for loop.
551  */
552 struct hash_entry *
_mesa_hash_table_next_entry_unsafe(const struct hash_table * ht,struct hash_entry * entry)553 _mesa_hash_table_next_entry_unsafe(const struct hash_table *ht, struct hash_entry *entry)
554 {
555    assert(!ht->deleted_entries);
556    if (!ht->entries)
557       return NULL;
558    if (entry == NULL)
559       entry = ht->table;
560    else
561       entry = entry + 1;
562    if (entry != ht->table + ht->size)
563       return entry->key ? entry : _mesa_hash_table_next_entry_unsafe(ht, entry);
564 
565    return NULL;
566 }
567 
568 /**
569  * This function is an iterator over the hash table.
570  *
571  * Pass in NULL for the first entry, as in the start of a for loop.  Note that
572  * an iteration over the table is O(table_size) not O(entries).
573  */
574 struct hash_entry *
_mesa_hash_table_next_entry(struct hash_table * ht,struct hash_entry * entry)575 _mesa_hash_table_next_entry(struct hash_table *ht,
576                             struct hash_entry *entry)
577 {
578    if (entry == NULL)
579       entry = ht->table;
580    else
581       entry = entry + 1;
582 
583    for (; entry != ht->table + ht->size; entry++) {
584       if (entry_is_present(ht, entry)) {
585          return entry;
586       }
587    }
588 
589    return NULL;
590 }
591 
592 /**
593  * Returns a random entry from the hash table.
594  *
595  * This may be useful in implementing random replacement (as opposed
596  * to just removing everything) in caches based on this hash table
597  * implementation.  @predicate may be used to filter entries, or may
598  * be set to NULL for no filtering.
599  */
600 struct hash_entry *
_mesa_hash_table_random_entry(struct hash_table * ht,bool (* predicate)(struct hash_entry * entry))601 _mesa_hash_table_random_entry(struct hash_table *ht,
602                               bool (*predicate)(struct hash_entry *entry))
603 {
604    struct hash_entry *entry;
605    uint32_t i = rand() % ht->size;
606 
607    if (ht->entries == 0)
608       return NULL;
609 
610    for (entry = ht->table + i; entry != ht->table + ht->size; entry++) {
611       if (entry_is_present(ht, entry) &&
612           (!predicate || predicate(entry))) {
613          return entry;
614       }
615    }
616 
617    for (entry = ht->table; entry != ht->table + i; entry++) {
618       if (entry_is_present(ht, entry) &&
619           (!predicate || predicate(entry))) {
620          return entry;
621       }
622    }
623 
624    return NULL;
625 }
626 
627 
628 uint32_t
_mesa_hash_data(const void * data,size_t size)629 _mesa_hash_data(const void *data, size_t size)
630 {
631    return XXH32(data, size, 0);
632 }
633 
634 uint32_t
_mesa_hash_data_with_seed(const void * data,size_t size,uint32_t seed)635 _mesa_hash_data_with_seed(const void *data, size_t size, uint32_t seed)
636 {
637    return XXH32(data, size, seed);
638 }
639 
640 uint32_t
_mesa_hash_int(const void * key)641 _mesa_hash_int(const void *key)
642 {
643    return XXH32(key, sizeof(int), 0);
644 }
645 
646 uint32_t
_mesa_hash_uint(const void * key)647 _mesa_hash_uint(const void *key)
648 {
649    return XXH32(key, sizeof(unsigned), 0);
650 }
651 
652 uint32_t
_mesa_hash_u32(const void * key)653 _mesa_hash_u32(const void *key)
654 {
655    return XXH32(key, 4, 0);
656 }
657 
658 /** FNV-1a string hash implementation */
659 uint32_t
_mesa_hash_string(const void * _key)660 _mesa_hash_string(const void *_key)
661 {
662    return _mesa_hash_string_with_length(_key, strlen((const char *)_key));
663 }
664 
665 uint32_t
_mesa_hash_string_with_length(const void * _key,unsigned length)666 _mesa_hash_string_with_length(const void *_key, unsigned length)
667 {
668    uint32_t hash = 0;
669    const char *key = _key;
670 #if defined(_WIN64) || defined(__x86_64__)
671    hash = (uint32_t)XXH64(key, length, hash);
672 #else
673    hash = XXH32(key, length, hash);
674 #endif
675    return hash;
676 }
677 
678 uint32_t
_mesa_hash_pointer(const void * pointer)679 _mesa_hash_pointer(const void *pointer)
680 {
681    uintptr_t num = (uintptr_t) pointer;
682    return (uint32_t) ((num >> 2) ^ (num >> 6) ^ (num >> 10) ^ (num >> 14));
683 }
684 
685 bool
_mesa_key_int_equal(const void * a,const void * b)686 _mesa_key_int_equal(const void *a, const void *b)
687 {
688    return *((const int *)a) == *((const int *)b);
689 }
690 
691 bool
_mesa_key_uint_equal(const void * a,const void * b)692 _mesa_key_uint_equal(const void *a, const void *b)
693 {
694 
695    return *((const unsigned *)a) == *((const unsigned *)b);
696 }
697 
698 bool
_mesa_key_u32_equal(const void * a,const void * b)699 _mesa_key_u32_equal(const void *a, const void *b)
700 {
701    return *((const uint32_t *)a) == *((const uint32_t *)b);
702 }
703 
704 /**
705  * String compare function for use as the comparison callback in
706  * _mesa_hash_table_create().
707  */
708 bool
_mesa_key_string_equal(const void * a,const void * b)709 _mesa_key_string_equal(const void *a, const void *b)
710 {
711    return strcmp(a, b) == 0;
712 }
713 
714 bool
_mesa_key_pointer_equal(const void * a,const void * b)715 _mesa_key_pointer_equal(const void *a, const void *b)
716 {
717    return a == b;
718 }
719 
720 /**
721  * Helper to create a hash table with pointer keys.
722  */
723 struct hash_table *
_mesa_pointer_hash_table_create(void * mem_ctx)724 _mesa_pointer_hash_table_create(void *mem_ctx)
725 {
726    return _mesa_hash_table_create(mem_ctx, _mesa_hash_pointer,
727                                   _mesa_key_pointer_equal);
728 }
729 
730 
731 bool
_mesa_hash_table_reserve(struct hash_table * ht,unsigned size)732 _mesa_hash_table_reserve(struct hash_table *ht, unsigned size)
733 {
734    if (size < ht->max_entries)
735       return true;
736    for (unsigned i = ht->size_index + 1; i < ARRAY_SIZE(hash_sizes); i++) {
737       if (hash_sizes[i].max_entries >= size) {
738          _mesa_hash_table_rehash(ht, i);
739          break;
740       }
741    }
742    return ht->max_entries >= size;
743 }
744 
745 /**
746  * Hash table wrapper which supports 64-bit keys.
747  *
748  * TODO: unify all hash table implementations.
749  */
750 
751 struct hash_key_u64 {
752    uint64_t value;
753 };
754 
755 static uint32_t
key_u64_hash(const void * key)756 key_u64_hash(const void *key)
757 {
758    return _mesa_hash_data(key, sizeof(struct hash_key_u64));
759 }
760 
761 static bool
key_u64_equals(const void * a,const void * b)762 key_u64_equals(const void *a, const void *b)
763 {
764    const struct hash_key_u64 *aa = a;
765    const struct hash_key_u64 *bb = b;
766 
767    return aa->value == bb->value;
768 }
769 
770 #define FREED_KEY_VALUE 0
771 
772 struct hash_table_u64 *
_mesa_hash_table_u64_create(void * mem_ctx)773 _mesa_hash_table_u64_create(void *mem_ctx)
774 {
775    STATIC_ASSERT(FREED_KEY_VALUE != DELETED_KEY_VALUE);
776    struct hash_table_u64 *ht;
777 
778    ht = CALLOC_STRUCT(hash_table_u64);
779    if (!ht)
780       return NULL;
781 
782    if (sizeof(void *) == 8) {
783       ht->table = _mesa_hash_table_create(mem_ctx, _mesa_hash_pointer,
784                                           _mesa_key_pointer_equal);
785    } else {
786       ht->table = _mesa_hash_table_create(mem_ctx, key_u64_hash,
787                                           key_u64_equals);
788    }
789 
790    if (ht->table)
791       _mesa_hash_table_set_deleted_key(ht->table, uint_key(DELETED_KEY_VALUE));
792 
793    return ht;
794 }
795 
796 static void
_mesa_hash_table_u64_delete_key(struct hash_entry * entry)797 _mesa_hash_table_u64_delete_key(struct hash_entry *entry)
798 {
799    if (sizeof(void *) == 8)
800       return;
801 
802    struct hash_key_u64 *_key = (struct hash_key_u64 *)entry->key;
803 
804    if (_key)
805       free(_key);
806 }
807 
808 void
_mesa_hash_table_u64_clear(struct hash_table_u64 * ht)809 _mesa_hash_table_u64_clear(struct hash_table_u64 *ht)
810 {
811    if (!ht)
812       return;
813 
814    _mesa_hash_table_clear(ht->table, _mesa_hash_table_u64_delete_key);
815    ht->freed_key_data = NULL;
816    ht->deleted_key_data = NULL;
817 }
818 
819 void
_mesa_hash_table_u64_destroy(struct hash_table_u64 * ht)820 _mesa_hash_table_u64_destroy(struct hash_table_u64 *ht)
821 {
822    if (!ht)
823       return;
824 
825    _mesa_hash_table_u64_clear(ht);
826    _mesa_hash_table_destroy(ht->table, NULL);
827    free(ht);
828 }
829 
830 void
_mesa_hash_table_u64_insert(struct hash_table_u64 * ht,uint64_t key,void * data)831 _mesa_hash_table_u64_insert(struct hash_table_u64 *ht, uint64_t key,
832                             void *data)
833 {
834    if (key == FREED_KEY_VALUE) {
835       ht->freed_key_data = data;
836       return;
837    }
838 
839    if (key == DELETED_KEY_VALUE) {
840       ht->deleted_key_data = data;
841       return;
842    }
843 
844    if (sizeof(void *) == 8) {
845       _mesa_hash_table_insert(ht->table, (void *)(uintptr_t)key, data);
846    } else {
847       struct hash_key_u64 *_key = CALLOC_STRUCT(hash_key_u64);
848 
849       if (!_key)
850          return;
851       _key->value = key;
852 
853       _mesa_hash_table_insert(ht->table, _key, data);
854    }
855 }
856 
857 static struct hash_entry *
hash_table_u64_search(struct hash_table_u64 * ht,uint64_t key)858 hash_table_u64_search(struct hash_table_u64 *ht, uint64_t key)
859 {
860    if (sizeof(void *) == 8) {
861       return _mesa_hash_table_search(ht->table, (void *)(uintptr_t)key);
862    } else {
863       struct hash_key_u64 _key = { .value = key };
864       return _mesa_hash_table_search(ht->table, &_key);
865    }
866 }
867 
868 void *
_mesa_hash_table_u64_search(struct hash_table_u64 * ht,uint64_t key)869 _mesa_hash_table_u64_search(struct hash_table_u64 *ht, uint64_t key)
870 {
871    struct hash_entry *entry;
872 
873    if (key == FREED_KEY_VALUE)
874       return ht->freed_key_data;
875 
876    if (key == DELETED_KEY_VALUE)
877       return ht->deleted_key_data;
878 
879    entry = hash_table_u64_search(ht, key);
880    if (!entry)
881       return NULL;
882 
883    return entry->data;
884 }
885 
886 void
_mesa_hash_table_u64_remove(struct hash_table_u64 * ht,uint64_t key)887 _mesa_hash_table_u64_remove(struct hash_table_u64 *ht, uint64_t key)
888 {
889    struct hash_entry *entry;
890 
891    if (key == FREED_KEY_VALUE) {
892       ht->freed_key_data = NULL;
893       return;
894    }
895 
896    if (key == DELETED_KEY_VALUE) {
897       ht->deleted_key_data = NULL;
898       return;
899    }
900 
901    entry = hash_table_u64_search(ht, key);
902    if (!entry)
903       return;
904 
905    if (sizeof(void *) == 8) {
906       _mesa_hash_table_remove(ht->table, entry);
907    } else {
908       struct hash_key *_key = (struct hash_key *)entry->key;
909 
910       _mesa_hash_table_remove(ht->table, entry);
911       free(_key);
912    }
913 }
914