1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-hash.c Generic hash table utility (internal to D-Bus implementation)
3 *
4 * Copyright (C) 2002 Red Hat, Inc.
5 * Copyright (c) 1991-1993 The Regents of the University of California.
6 * Copyright (c) 1994 Sun Microsystems, Inc.
7 *
8 * Hash table implementation based on generic/tclHash.c from the Tcl
9 * source code. The original Tcl license applies to portions of the
10 * code from tclHash.c; the Tcl license follows this standad D-Bus
11 * license information.
12 *
13 * Licensed under the Academic Free License version 2.1
14 *
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2 of the License, or
18 * (at your option) any later version.
19 *
20 * This program is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 * GNU General Public License for more details.
24 *
25 * You should have received a copy of the GNU General Public License
26 * along with this program; if not, write to the Free Software
27 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
28 *
29 */
30 /*
31 * The following copyright applies to code from the Tcl distribution.
32 *
33 * Copyright (c) 1991-1993 The Regents of the University of California.
34 * Copyright (c) 1994 Sun Microsystems, Inc.
35 *
36 * This software is copyrighted by the Regents of the University of
37 * California, Sun Microsystems, Inc., Scriptics Corporation, and
38 * other parties. The following terms apply to all files associated
39 * with the software unless explicitly disclaimed in individual files.
40 *
41 * The authors hereby grant permission to use, copy, modify,
42 * distribute, and license this software and its documentation for any
43 * purpose, provided that existing copyright notices are retained in
44 * all copies and that this notice is included verbatim in any
45 * distributions. No written agreement, license, or royalty fee is
46 * required for any of the authorized uses. Modifications to this
47 * software may be copyrighted by their authors and need not follow
48 * the licensing terms described here, provided that the new terms are
49 * clearly indicated on the first page of each file where they apply.
50 *
51 * IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY
52 * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
53 * DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION,
54 * OR ANY DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED
55 * OF THE POSSIBILITY OF SUCH DAMAGE.
56 *
57 * THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
58 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
59 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND
60 * NON-INFRINGEMENT. THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS,
61 * AND THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE
62 * MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
63 *
64 * GOVERNMENT USE: If you are acquiring this software on behalf of the
65 * U.S. government, the Government shall have only "Restricted Rights"
66 * in the software and related documentation as defined in the Federal
67 * Acquisition Regulations (FARs) in Clause 52.227.19 (c) (2). If you
68 * are acquiring the software on behalf of the Department of Defense,
69 * the software shall be classified as "Commercial Computer Software"
70 * and the Government shall have only "Restricted Rights" as defined
71 * in Clause 252.227-7013 (c) (1) of DFARs. Notwithstanding the
72 * foregoing, the authors grant the U.S. Government and others acting
73 * in its behalf permission to use and distribute the software in
74 * accordance with the terms specified in this license.
75 */
76
77 #include <config.h>
78 #include "dbus-hash.h"
79 #include "dbus-internals.h"
80 #include "dbus-mempool.h"
81
82 /**
83 * @defgroup DBusHashTable Hash table
84 * @ingroup DBusInternals
85 * @brief DBusHashTable data structure
86 *
87 * Types and functions related to DBusHashTable.
88 */
89
90 /**
91 * @defgroup DBusHashTableInternals Hash table implementation details
92 * @ingroup DBusInternals
93 * @brief DBusHashTable implementation details
94 *
95 * The guts of DBusHashTable.
96 *
97 * @{
98 */
99
100 /**
101 * When there are this many entries per bucket, on average, rebuild
102 * the hash table to make it larger.
103 */
104 #define REBUILD_MULTIPLIER 3
105
106 /**
107 * Takes a preliminary integer hash value and produces an index into a
108 * hash tables bucket list. The idea is to make it so that
109 * preliminary values that are arbitrarily similar will end up in
110 * different buckets. The hash function was taken from a
111 * random-number generator. (This is used to hash integers.)
112 *
113 * The down_shift drops off the high bits of the hash index, and
114 * decreases as we increase the number of hash buckets (to keep more
115 * range in the hash index). The mask also strips high bits and strips
116 * fewer high bits as the number of hash buckets increases.
117 * I don't understand two things: why is the initial downshift 28
118 * to keep 4 bits when the initial mask is 011 to keep 2 bits,
119 * and why do we have both a mask and a downshift?
120 *
121 */
122 #define RANDOM_INDEX(table, i) \
123 (((((intptr_t) (i))*1103515245) >> (table)->down_shift) & (table)->mask)
124
125 /**
126 * Initial number of buckets in hash table (hash table statically
127 * allocates its buckets for this size and below).
128 * The initial mask has to be synced to this.
129 */
130 #define DBUS_SMALL_HASH_TABLE 4
131
132 /**
133 * Typedef for DBusHashEntry
134 */
135 typedef struct DBusHashEntry DBusHashEntry;
136
137 /**
138 * @brief Internal representation of a hash entry.
139 *
140 * A single entry (key-value pair) in the hash table.
141 * Internal to hash table implementation.
142 */
143 struct DBusHashEntry
144 {
145 DBusHashEntry *next; /**< Pointer to next entry in this
146 * hash bucket, or #NULL for end of
147 * chain.
148 */
149 void *key; /**< Hash key */
150 void *value; /**< Hash value */
151 };
152
153 /**
154 * Function used to find and optionally create a hash entry.
155 */
156 typedef DBusHashEntry* (* DBusFindEntryFunction) (DBusHashTable *table,
157 void *key,
158 dbus_bool_t create_if_not_found,
159 DBusHashEntry ***bucket,
160 DBusPreallocatedHash *preallocated);
161
162 /**
163 * @brief Internals of DBusHashTable.
164 *
165 * Hash table internals. Hash tables are opaque objects, they must be
166 * used via accessor functions.
167 */
168 struct DBusHashTable {
169 int refcount; /**< Reference count */
170
171 DBusHashEntry **buckets; /**< Pointer to bucket array. Each
172 * element points to first entry in
173 * bucket's hash chain, or #NULL.
174 */
175 DBusHashEntry *static_buckets[DBUS_SMALL_HASH_TABLE];
176 /**< Bucket array used for small tables
177 * (to avoid mallocs and frees).
178 */
179 int n_buckets; /**< Total number of buckets allocated
180 * at **buckets.
181 */
182 int n_entries; /**< Total number of entries present
183 * in table.
184 */
185 int hi_rebuild_size; /**< Enlarge table when n_entries gets
186 * to be this large.
187 */
188 int lo_rebuild_size; /**< Shrink table when n_entries gets
189 * below this.
190 */
191 int down_shift; /**< Shift count used in hashing
192 * function. Designed to use high-
193 * order bits of randomized keys.
194 */
195 int mask; /**< Mask value used in hashing
196 * function.
197 */
198 DBusHashType key_type; /**< Type of keys used in this table */
199
200
201 DBusFindEntryFunction find_function; /**< Function for finding entries */
202
203 DBusFreeFunction free_key_function; /**< Function to free keys */
204 DBusFreeFunction free_value_function; /**< Function to free values */
205
206 DBusMemPool *entry_pool; /**< Memory pool for hash entries */
207 };
208
209 /**
210 * @brief Internals of DBusHashIter.
211 */
212 typedef struct
213 {
214 DBusHashTable *table; /**< Pointer to table containing entry. */
215 DBusHashEntry **bucket; /**< Pointer to bucket that points to
216 * first entry in this entry's chain:
217 * used for deleting the entry.
218 */
219 DBusHashEntry *entry; /**< Current hash entry */
220 DBusHashEntry *next_entry; /**< Next entry to be iterated onto in current bucket */
221 int next_bucket; /**< index of next bucket */
222 int n_entries_on_init; /**< used to detect table resize since initialization */
223 } DBusRealHashIter;
224
225 _DBUS_STATIC_ASSERT (sizeof (DBusRealHashIter) == sizeof (DBusHashIter));
226
227 static DBusHashEntry* find_direct_function (DBusHashTable *table,
228 void *key,
229 dbus_bool_t create_if_not_found,
230 DBusHashEntry ***bucket,
231 DBusPreallocatedHash *preallocated);
232 static DBusHashEntry* find_string_function (DBusHashTable *table,
233 void *key,
234 dbus_bool_t create_if_not_found,
235 DBusHashEntry ***bucket,
236 DBusPreallocatedHash *preallocated);
237 static unsigned int string_hash (const char *str);
238 static void rebuild_table (DBusHashTable *table);
239 static DBusHashEntry* alloc_entry (DBusHashTable *table);
240 static void remove_entry (DBusHashTable *table,
241 DBusHashEntry **bucket,
242 DBusHashEntry *entry);
243 static void free_entry (DBusHashTable *table,
244 DBusHashEntry *entry);
245 static void free_entry_data (DBusHashTable *table,
246 DBusHashEntry *entry);
247
248
249 /** @} */
250
251 /**
252 * @addtogroup DBusHashTable
253 * @{
254 */
255
256 /**
257 * @typedef DBusHashIter
258 *
259 * Public opaque hash table iterator object.
260 */
261
262 /**
263 * @typedef DBusHashTable
264 *
265 * Public opaque hash table object.
266 */
267
268 /**
269 * @typedef DBusHashType
270 *
271 * Indicates the type of a key in the hash table.
272 */
273
274 /**
275 * Constructs a new hash table. Should be freed with
276 * _dbus_hash_table_unref(). If memory cannot be
277 * allocated for the hash table, returns #NULL.
278 *
279 * @param type the type of hash key to use.
280 * @param key_free_function function to free hash keys.
281 * @param value_free_function function to free hash values.
282 * @returns a new DBusHashTable or #NULL if no memory.
283 */
284 DBusHashTable*
_dbus_hash_table_new(DBusHashType type,DBusFreeFunction key_free_function,DBusFreeFunction value_free_function)285 _dbus_hash_table_new (DBusHashType type,
286 DBusFreeFunction key_free_function,
287 DBusFreeFunction value_free_function)
288 {
289 DBusHashTable *table;
290 DBusMemPool *entry_pool;
291
292 table = dbus_new0 (DBusHashTable, 1);
293 if (table == NULL)
294 return NULL;
295
296 entry_pool = _dbus_mem_pool_new (sizeof (DBusHashEntry), TRUE);
297 if (entry_pool == NULL)
298 {
299 dbus_free (table);
300 return NULL;
301 }
302
303 table->refcount = 1;
304 table->entry_pool = entry_pool;
305
306 _dbus_assert (DBUS_SMALL_HASH_TABLE == _DBUS_N_ELEMENTS (table->static_buckets));
307
308 table->buckets = table->static_buckets;
309 table->n_buckets = DBUS_SMALL_HASH_TABLE;
310 table->n_entries = 0;
311 table->hi_rebuild_size = DBUS_SMALL_HASH_TABLE * REBUILD_MULTIPLIER;
312 table->lo_rebuild_size = 0;
313 table->down_shift = 28;
314 table->mask = 3;
315 table->key_type = type;
316
317 _dbus_assert (table->mask < table->n_buckets);
318
319 switch (table->key_type)
320 {
321 case DBUS_HASH_INT:
322 case DBUS_HASH_UINTPTR:
323 table->find_function = find_direct_function;
324 break;
325 case DBUS_HASH_STRING:
326 table->find_function = find_string_function;
327 break;
328 default:
329 _dbus_assert_not_reached ("Unknown hash table type");
330 break;
331 }
332
333 table->free_key_function = key_free_function;
334 table->free_value_function = value_free_function;
335
336 return table;
337 }
338
339
340 /**
341 * Increments the reference count for a hash table.
342 *
343 * @param table the hash table to add a reference to.
344 * @returns the hash table.
345 */
346 DBusHashTable *
_dbus_hash_table_ref(DBusHashTable * table)347 _dbus_hash_table_ref (DBusHashTable *table)
348 {
349 table->refcount += 1;
350
351 return table;
352 }
353
354 /**
355 * Decrements the reference count for a hash table,
356 * freeing the hash table if the count reaches zero.
357 *
358 * @param table the hash table to remove a reference from.
359 */
360 void
_dbus_hash_table_unref(DBusHashTable * table)361 _dbus_hash_table_unref (DBusHashTable *table)
362 {
363 table->refcount -= 1;
364
365 if (table->refcount == 0)
366 {
367 #if 0
368 DBusHashEntry *entry;
369 DBusHashEntry *next;
370 int i;
371
372 /* Free the entries in the table. */
373 for (i = 0; i < table->n_buckets; i++)
374 {
375 entry = table->buckets[i];
376 while (entry != NULL)
377 {
378 next = entry->next;
379
380 free_entry (table, entry);
381
382 entry = next;
383 }
384 }
385 #else
386 DBusHashEntry *entry;
387 int i;
388
389 /* Free the entries in the table. */
390 for (i = 0; i < table->n_buckets; i++)
391 {
392 entry = table->buckets[i];
393 while (entry != NULL)
394 {
395 free_entry_data (table, entry);
396
397 entry = entry->next;
398 }
399 }
400 /* We can do this very quickly with memory pools ;-) */
401 _dbus_mem_pool_free (table->entry_pool);
402 #endif
403
404 /* Free the bucket array, if it was dynamically allocated. */
405 if (table->buckets != table->static_buckets)
406 dbus_free (table->buckets);
407
408 dbus_free (table);
409 }
410 }
411
412 /**
413 * Removed all entries from a hash table.
414 *
415 * @param table the hash table to remove all entries from.
416 */
417 void
_dbus_hash_table_remove_all(DBusHashTable * table)418 _dbus_hash_table_remove_all (DBusHashTable *table)
419 {
420 DBusHashIter iter;
421 _dbus_hash_iter_init (table, &iter);
422 while (_dbus_hash_iter_next (&iter))
423 {
424 _dbus_hash_iter_remove_entry(&iter);
425 }
426 }
427
428 static DBusHashEntry*
alloc_entry(DBusHashTable * table)429 alloc_entry (DBusHashTable *table)
430 {
431 DBusHashEntry *entry;
432
433 entry = _dbus_mem_pool_alloc (table->entry_pool);
434
435 return entry;
436 }
437
438 static void
free_entry_data(DBusHashTable * table,DBusHashEntry * entry)439 free_entry_data (DBusHashTable *table,
440 DBusHashEntry *entry)
441 {
442 if (table->free_key_function)
443 (* table->free_key_function) (entry->key);
444 if (table->free_value_function)
445 (* table->free_value_function) (entry->value);
446 }
447
448 static void
free_entry(DBusHashTable * table,DBusHashEntry * entry)449 free_entry (DBusHashTable *table,
450 DBusHashEntry *entry)
451 {
452 free_entry_data (table, entry);
453 _dbus_mem_pool_dealloc (table->entry_pool, entry);
454 }
455
456 static void
remove_entry(DBusHashTable * table,DBusHashEntry ** bucket,DBusHashEntry * entry)457 remove_entry (DBusHashTable *table,
458 DBusHashEntry **bucket,
459 DBusHashEntry *entry)
460 {
461 _dbus_assert (table != NULL);
462 _dbus_assert (bucket != NULL);
463 _dbus_assert (*bucket != NULL);
464 _dbus_assert (entry != NULL);
465
466 if (*bucket == entry)
467 *bucket = entry->next;
468 else
469 {
470 DBusHashEntry *prev;
471 prev = *bucket;
472
473 while (prev->next != entry)
474 prev = prev->next;
475
476 _dbus_assert (prev != NULL);
477
478 prev->next = entry->next;
479 }
480
481 table->n_entries -= 1;
482 free_entry (table, entry);
483 }
484
485 /**
486 * Initializes a hash table iterator. To iterate over all entries in a
487 * hash table, use the following code (the printf assumes a hash
488 * from strings to strings obviously):
489 *
490 * @code
491 * DBusHashIter iter;
492 *
493 * _dbus_hash_iter_init (table, &iter);
494 * while (_dbus_hash_iter_next (&iter))
495 * {
496 * printf ("The first key is %s and value is %s\n",
497 * _dbus_hash_iter_get_string_key (&iter),
498 * _dbus_hash_iter_get_value (&iter));
499 * }
500 *
501 *
502 * @endcode
503 *
504 * The iterator is initialized pointing "one before" the first hash
505 * entry. The first call to _dbus_hash_iter_next() moves it onto
506 * the first valid entry or returns #FALSE if the hash table is
507 * empty. Subsequent calls move to the next valid entry or return
508 * #FALSE if there are no more entries.
509 *
510 * Note that it is guaranteed to be safe to remove a hash entry during
511 * iteration, but it is not safe to add a hash entry.
512 *
513 * @param table the hash table to iterate over.
514 * @param iter the iterator to initialize.
515 */
516 void
_dbus_hash_iter_init(DBusHashTable * table,DBusHashIter * iter)517 _dbus_hash_iter_init (DBusHashTable *table,
518 DBusHashIter *iter)
519 {
520 DBusRealHashIter *real;
521
522 _DBUS_STATIC_ASSERT (sizeof (DBusHashIter) == sizeof (DBusRealHashIter));
523
524 real = (DBusRealHashIter*) iter;
525
526 real->table = table;
527 real->bucket = NULL;
528 real->entry = NULL;
529 real->next_entry = NULL;
530 real->next_bucket = 0;
531 real->n_entries_on_init = table->n_entries;
532 }
533
534 /**
535 * Move the hash iterator forward one step, to the next hash entry.
536 * The documentation for _dbus_hash_iter_init() explains in more
537 * detail.
538 *
539 * @param iter the iterator to move forward.
540 * @returns #FALSE if there are no more entries to move to.
541 */
542 dbus_bool_t
_dbus_hash_iter_next(DBusHashIter * iter)543 _dbus_hash_iter_next (DBusHashIter *iter)
544 {
545 DBusRealHashIter *real;
546
547 _DBUS_STATIC_ASSERT (sizeof (DBusHashIter) == sizeof (DBusRealHashIter));
548
549 real = (DBusRealHashIter*) iter;
550
551 /* if this assertion failed someone probably added hash entries
552 * during iteration, which is bad.
553 */
554 _dbus_assert (real->n_entries_on_init >= real->table->n_entries);
555
556 /* Remember that real->entry may have been deleted */
557
558 while (real->next_entry == NULL)
559 {
560 if (real->next_bucket >= real->table->n_buckets)
561 {
562 /* invalidate iter and return false */
563 real->entry = NULL;
564 real->table = NULL;
565 real->bucket = NULL;
566 return FALSE;
567 }
568
569 real->bucket = &(real->table->buckets[real->next_bucket]);
570 real->next_entry = *(real->bucket);
571 real->next_bucket += 1;
572 }
573
574 _dbus_assert (real->next_entry != NULL);
575 _dbus_assert (real->bucket != NULL);
576
577 real->entry = real->next_entry;
578 real->next_entry = real->entry->next;
579
580 return TRUE;
581 }
582
583 /**
584 * Removes the current entry from the hash table.
585 * If a key_free_function or value_free_function
586 * was provided to _dbus_hash_table_new(),
587 * frees the key and/or value for this entry.
588 *
589 * @param iter the hash table iterator.
590 */
591 void
_dbus_hash_iter_remove_entry(DBusHashIter * iter)592 _dbus_hash_iter_remove_entry (DBusHashIter *iter)
593 {
594 DBusRealHashIter *real;
595
596 real = (DBusRealHashIter*) iter;
597
598 _dbus_assert (real->table != NULL);
599 _dbus_assert (real->entry != NULL);
600 _dbus_assert (real->bucket != NULL);
601
602 remove_entry (real->table, real->bucket, real->entry);
603
604 real->entry = NULL; /* make it crash if you try to use this entry */
605 }
606
607 /**
608 * Gets the value of the current entry.
609 *
610 * @param iter the hash table iterator.
611 */
612 void*
_dbus_hash_iter_get_value(DBusHashIter * iter)613 _dbus_hash_iter_get_value (DBusHashIter *iter)
614 {
615 DBusRealHashIter *real;
616
617 real = (DBusRealHashIter*) iter;
618
619 _dbus_assert (real->table != NULL);
620 _dbus_assert (real->entry != NULL);
621
622 return real->entry->value;
623 }
624
625 /**
626 * Sets the value of the current entry.
627 * If the hash table has a value_free_function
628 * it will be used to free the previous value.
629 * The hash table will own the passed-in value
630 * (it will not be copied).
631 *
632 * @param iter the hash table iterator.
633 * @param value the new value.
634 */
635 void
_dbus_hash_iter_set_value(DBusHashIter * iter,void * value)636 _dbus_hash_iter_set_value (DBusHashIter *iter,
637 void *value)
638 {
639 DBusRealHashIter *real;
640
641 real = (DBusRealHashIter*) iter;
642
643 _dbus_assert (real->table != NULL);
644 _dbus_assert (real->entry != NULL);
645
646 if (real->table->free_value_function && value != real->entry->value)
647 (* real->table->free_value_function) (real->entry->value);
648
649 real->entry->value = value;
650 }
651
652 /**
653 * Gets the key for the current entry.
654 * Only works for hash tables of type #DBUS_HASH_INT.
655 *
656 * @param iter the hash table iterator.
657 */
658 int
_dbus_hash_iter_get_int_key(DBusHashIter * iter)659 _dbus_hash_iter_get_int_key (DBusHashIter *iter)
660 {
661 DBusRealHashIter *real;
662
663 real = (DBusRealHashIter*) iter;
664
665 _dbus_assert (real->table != NULL);
666 _dbus_assert (real->entry != NULL);
667
668 return _DBUS_POINTER_TO_INT (real->entry->key);
669 }
670
671 /**
672 * Gets the key for the current entry.
673 * Only works for hash tables of type #DBUS_HASH_UINTPTR.
674 *
675 * @param iter the hash table iterator.
676 */
677 uintptr_t
_dbus_hash_iter_get_uintptr_key(DBusHashIter * iter)678 _dbus_hash_iter_get_uintptr_key (DBusHashIter *iter)
679 {
680 DBusRealHashIter *real;
681
682 real = (DBusRealHashIter*) iter;
683
684 _dbus_assert (real->table != NULL);
685 _dbus_assert (real->entry != NULL);
686
687 return (uintptr_t) real->entry->key;
688 }
689
690 /**
691 * Gets the key for the current entry.
692 * Only works for hash tables of type #DBUS_HASH_STRING
693 * @param iter the hash table iterator.
694 */
695 const char*
_dbus_hash_iter_get_string_key(DBusHashIter * iter)696 _dbus_hash_iter_get_string_key (DBusHashIter *iter)
697 {
698 DBusRealHashIter *real;
699
700 real = (DBusRealHashIter*) iter;
701
702 _dbus_assert (real->table != NULL);
703 _dbus_assert (real->entry != NULL);
704
705 return real->entry->key;
706 }
707
708 /**
709 * A low-level but efficient interface for manipulating the hash
710 * table. It's efficient because you can get, set, and optionally
711 * create the hash entry while only running the hash function one
712 * time.
713 *
714 * Note that while calling _dbus_hash_iter_next() on the iterator
715 * filled in by this function may work, it's completely
716 * undefined which entries are after this iter and which
717 * are before it. So it would be silly to iterate using this
718 * iterator.
719 *
720 * If the hash entry is created, its value will be initialized
721 * to all bits zero.
722 *
723 * #FALSE may be returned due to memory allocation failure, or
724 * because create_if_not_found was #FALSE and the entry
725 * did not exist.
726 *
727 * If create_if_not_found is #TRUE, the hash
728 * table takes ownership of the key that's passed in (either using it to create
729 * the entry, or freeing it immediately).
730 *
731 * For a hash table of type #DBUS_HASH_INT, cast the int
732 * key to the key parameter using #_DBUS_INT_TO_POINTER().
733 *
734 * @param table the hash table.
735 * @param key the hash key.
736 * @param create_if_not_found if #TRUE, create the entry if it didn't exist.
737 * @param iter the iterator to initialize.
738 * @returns #TRUE if the hash entry now exists (and the iterator is thus valid).
739 */
740 dbus_bool_t
_dbus_hash_iter_lookup(DBusHashTable * table,void * key,dbus_bool_t create_if_not_found,DBusHashIter * iter)741 _dbus_hash_iter_lookup (DBusHashTable *table,
742 void *key,
743 dbus_bool_t create_if_not_found,
744 DBusHashIter *iter)
745 {
746 DBusRealHashIter *real;
747 DBusHashEntry *entry;
748 DBusHashEntry **bucket;
749
750 _DBUS_STATIC_ASSERT (sizeof (DBusHashIter) == sizeof (DBusRealHashIter));
751
752 real = (DBusRealHashIter*) iter;
753
754 entry = (* table->find_function) (table, key, create_if_not_found, &bucket, NULL);
755
756 if (entry == NULL)
757 return FALSE;
758
759 if (create_if_not_found)
760 {
761 if (table->free_key_function && entry->key != key)
762 (* table->free_key_function) (entry->key);
763
764 entry->key = key;
765 }
766
767 real->table = table;
768 real->bucket = bucket;
769 real->entry = entry;
770 real->next_entry = entry->next;
771 real->next_bucket = (bucket - table->buckets) + 1;
772 real->n_entries_on_init = table->n_entries;
773
774 _dbus_assert (&(table->buckets[real->next_bucket-1]) == real->bucket);
775
776 return TRUE;
777 }
778
779 static void
add_allocated_entry(DBusHashTable * table,DBusHashEntry * entry,unsigned int idx,void * key,DBusHashEntry *** bucket)780 add_allocated_entry (DBusHashTable *table,
781 DBusHashEntry *entry,
782 unsigned int idx,
783 void *key,
784 DBusHashEntry ***bucket)
785 {
786 DBusHashEntry **b;
787
788 entry->key = key;
789
790 b = &(table->buckets[idx]);
791 entry->next = *b;
792 *b = entry;
793
794 if (bucket)
795 *bucket = b;
796
797 table->n_entries += 1;
798
799 /* note we ONLY rebuild when ADDING - because you can iterate over a
800 * table and remove entries safely.
801 */
802 if (table->n_entries >= table->hi_rebuild_size ||
803 table->n_entries < table->lo_rebuild_size)
804 rebuild_table (table);
805 }
806
807 static DBusHashEntry*
add_entry(DBusHashTable * table,unsigned int idx,void * key,DBusHashEntry *** bucket,DBusPreallocatedHash * preallocated)808 add_entry (DBusHashTable *table,
809 unsigned int idx,
810 void *key,
811 DBusHashEntry ***bucket,
812 DBusPreallocatedHash *preallocated)
813 {
814 DBusHashEntry *entry;
815
816 if (preallocated == NULL)
817 {
818 entry = alloc_entry (table);
819 if (entry == NULL)
820 {
821 if (bucket)
822 *bucket = NULL;
823 return NULL;
824 }
825 }
826 else
827 {
828 entry = (DBusHashEntry*) preallocated;
829 }
830
831 add_allocated_entry (table, entry, idx, key, bucket);
832
833 return entry;
834 }
835
836 /* This is g_str_hash from GLib which was
837 * extensively discussed/tested/profiled
838 */
839 static unsigned int
string_hash(const char * str)840 string_hash (const char *str)
841 {
842 const char *p = str;
843 unsigned int h = *p;
844
845 if (h)
846 for (p += 1; *p != '\0'; p++)
847 h = (h << 5) - h + *p;
848
849 return h;
850 }
851
852 /** Key comparison function */
853 typedef int (* KeyCompareFunc) (const void *key_a, const void *key_b);
854
855 static DBusHashEntry*
find_generic_function(DBusHashTable * table,void * key,unsigned int idx,KeyCompareFunc compare_func,dbus_bool_t create_if_not_found,DBusHashEntry *** bucket,DBusPreallocatedHash * preallocated)856 find_generic_function (DBusHashTable *table,
857 void *key,
858 unsigned int idx,
859 KeyCompareFunc compare_func,
860 dbus_bool_t create_if_not_found,
861 DBusHashEntry ***bucket,
862 DBusPreallocatedHash *preallocated)
863 {
864 DBusHashEntry *entry;
865
866 if (bucket)
867 *bucket = NULL;
868
869 /* Search all of the entries in this bucket. */
870 entry = table->buckets[idx];
871 while (entry != NULL)
872 {
873 if ((compare_func == NULL && key == entry->key) ||
874 (compare_func != NULL && (* compare_func) (key, entry->key) == 0))
875 {
876 if (bucket)
877 *bucket = &(table->buckets[idx]);
878
879 if (preallocated)
880 _dbus_hash_table_free_preallocated_entry (table, preallocated);
881
882 return entry;
883 }
884
885 entry = entry->next;
886 }
887
888 if (create_if_not_found)
889 entry = add_entry (table, idx, key, bucket, preallocated);
890 else if (preallocated)
891 _dbus_hash_table_free_preallocated_entry (table, preallocated);
892
893 return entry;
894 }
895
896 static DBusHashEntry*
find_string_function(DBusHashTable * table,void * key,dbus_bool_t create_if_not_found,DBusHashEntry *** bucket,DBusPreallocatedHash * preallocated)897 find_string_function (DBusHashTable *table,
898 void *key,
899 dbus_bool_t create_if_not_found,
900 DBusHashEntry ***bucket,
901 DBusPreallocatedHash *preallocated)
902 {
903 unsigned int idx;
904
905 idx = string_hash (key) & table->mask;
906
907 return find_generic_function (table, key, idx,
908 (KeyCompareFunc) strcmp, create_if_not_found, bucket,
909 preallocated);
910 }
911
912 static DBusHashEntry*
find_direct_function(DBusHashTable * table,void * key,dbus_bool_t create_if_not_found,DBusHashEntry *** bucket,DBusPreallocatedHash * preallocated)913 find_direct_function (DBusHashTable *table,
914 void *key,
915 dbus_bool_t create_if_not_found,
916 DBusHashEntry ***bucket,
917 DBusPreallocatedHash *preallocated)
918 {
919 unsigned int idx;
920
921 idx = RANDOM_INDEX (table, key) & table->mask;
922
923
924 return find_generic_function (table, key, idx,
925 NULL, create_if_not_found, bucket,
926 preallocated);
927 }
928
929 static void
rebuild_table(DBusHashTable * table)930 rebuild_table (DBusHashTable *table)
931 {
932 int old_size;
933 int new_buckets;
934 DBusHashEntry **old_buckets;
935 DBusHashEntry **old_chain;
936 DBusHashEntry *entry;
937 dbus_bool_t growing;
938
939 /*
940 * Allocate and initialize the new bucket array, and set up
941 * hashing constants for new array size.
942 */
943
944 growing = table->n_entries >= table->hi_rebuild_size;
945
946 old_size = table->n_buckets;
947 old_buckets = table->buckets;
948
949 if (growing)
950 {
951 /* overflow paranoia */
952 if (table->n_buckets < _DBUS_INT_MAX / 4 &&
953 table->down_shift >= 2)
954 new_buckets = table->n_buckets * 4;
955 else
956 return; /* can't grow anymore */
957 }
958 else
959 {
960 new_buckets = table->n_buckets / 4;
961 if (new_buckets < DBUS_SMALL_HASH_TABLE)
962 return; /* don't bother shrinking this far */
963 }
964
965 table->buckets = dbus_new0 (DBusHashEntry*, new_buckets);
966 if (table->buckets == NULL)
967 {
968 /* out of memory, yay - just don't reallocate, the table will
969 * still work, albeit more slowly.
970 */
971 table->buckets = old_buckets;
972 return;
973 }
974
975 table->n_buckets = new_buckets;
976
977 if (growing)
978 {
979 table->lo_rebuild_size = table->hi_rebuild_size;
980 table->hi_rebuild_size *= 4;
981
982 table->down_shift -= 2; /* keep 2 more high bits */
983 table->mask = (table->mask << 2) + 3; /* keep 2 more high bits */
984 }
985 else
986 {
987 table->hi_rebuild_size = table->lo_rebuild_size;
988 table->lo_rebuild_size /= 4;
989
990 table->down_shift += 2; /* keep 2 fewer high bits */
991 table->mask = table->mask >> 2; /* keep 2 fewer high bits */
992 }
993
994 #if 0
995 printf ("%s table to lo = %d hi = %d downshift = %d mask = 0x%x\n",
996 growing ? "GROW" : "SHRINK",
997 table->lo_rebuild_size,
998 table->hi_rebuild_size,
999 table->down_shift,
1000 table->mask);
1001 #endif
1002
1003 _dbus_assert (table->lo_rebuild_size >= 0);
1004 _dbus_assert (table->hi_rebuild_size > table->lo_rebuild_size);
1005 _dbus_assert (table->down_shift >= 0);
1006 _dbus_assert (table->mask != 0);
1007 /* the mask is essentially the max index */
1008 _dbus_assert (table->mask < table->n_buckets);
1009
1010 /*
1011 * Rehash all of the existing entries into the new bucket array.
1012 */
1013
1014 for (old_chain = old_buckets; old_size > 0; old_size--, old_chain++)
1015 {
1016 for (entry = *old_chain; entry != NULL; entry = *old_chain)
1017 {
1018 unsigned int idx;
1019 DBusHashEntry **bucket;
1020
1021 *old_chain = entry->next;
1022 switch (table->key_type)
1023 {
1024 case DBUS_HASH_STRING:
1025 idx = string_hash (entry->key) & table->mask;
1026 break;
1027 case DBUS_HASH_INT:
1028 case DBUS_HASH_UINTPTR:
1029 idx = RANDOM_INDEX (table, entry->key);
1030 break;
1031 default:
1032 idx = 0;
1033 _dbus_assert_not_reached ("Unknown hash table type");
1034 break;
1035 }
1036
1037 bucket = &(table->buckets[idx]);
1038 entry->next = *bucket;
1039 *bucket = entry;
1040 }
1041 }
1042
1043 /* Free the old bucket array, if it was dynamically allocated. */
1044
1045 if (old_buckets != table->static_buckets)
1046 dbus_free (old_buckets);
1047 }
1048
1049 /**
1050 * Looks up the value for a given string in a hash table
1051 * of type #DBUS_HASH_STRING. Returns %NULL if the value
1052 * is not present. (A not-present entry is indistinguishable
1053 * from an entry with a value of %NULL.)
1054 * @param table the hash table.
1055 * @param key the string to look up.
1056 * @returns the value of the hash entry.
1057 */
1058 void*
_dbus_hash_table_lookup_string(DBusHashTable * table,const char * key)1059 _dbus_hash_table_lookup_string (DBusHashTable *table,
1060 const char *key)
1061 {
1062 DBusHashEntry *entry;
1063
1064 _dbus_assert (table->key_type == DBUS_HASH_STRING);
1065
1066 entry = (* table->find_function) (table, (char*) key, FALSE, NULL, NULL);
1067
1068 if (entry)
1069 return entry->value;
1070 else
1071 return NULL;
1072 }
1073
1074 /**
1075 * Looks up the value for a given integer in a hash table
1076 * of type #DBUS_HASH_INT. Returns %NULL if the value
1077 * is not present. (A not-present entry is indistinguishable
1078 * from an entry with a value of %NULL.)
1079 * @param table the hash table.
1080 * @param key the integer to look up.
1081 * @returns the value of the hash entry.
1082 */
1083 void*
_dbus_hash_table_lookup_int(DBusHashTable * table,int key)1084 _dbus_hash_table_lookup_int (DBusHashTable *table,
1085 int key)
1086 {
1087 DBusHashEntry *entry;
1088
1089 _dbus_assert (table->key_type == DBUS_HASH_INT);
1090
1091 entry = (* table->find_function) (table, _DBUS_INT_TO_POINTER (key), FALSE, NULL, NULL);
1092
1093 if (entry)
1094 return entry->value;
1095 else
1096 return NULL;
1097 }
1098
1099 /**
1100 * Looks up the value for a given integer in a hash table
1101 * of type #DBUS_HASH_UINTPTR. Returns %NULL if the value
1102 * is not present. (A not-present entry is indistinguishable
1103 * from an entry with a value of %NULL.)
1104 * @param table the hash table.
1105 * @param key the integer to look up.
1106 * @returns the value of the hash entry.
1107 */
1108 void*
_dbus_hash_table_lookup_uintptr(DBusHashTable * table,uintptr_t key)1109 _dbus_hash_table_lookup_uintptr (DBusHashTable *table,
1110 uintptr_t key)
1111 {
1112 DBusHashEntry *entry;
1113
1114 _dbus_assert (table->key_type == DBUS_HASH_UINTPTR);
1115
1116 entry = (* table->find_function) (table, (void*) key, FALSE, NULL, NULL);
1117
1118 if (entry)
1119 return entry->value;
1120 else
1121 return NULL;
1122 }
1123
1124 /**
1125 * Removes the hash entry for the given key. If no hash entry
1126 * for the key exists, does nothing.
1127 *
1128 * @param table the hash table.
1129 * @param key the hash key.
1130 * @returns #TRUE if the entry existed
1131 */
1132 dbus_bool_t
_dbus_hash_table_remove_string(DBusHashTable * table,const char * key)1133 _dbus_hash_table_remove_string (DBusHashTable *table,
1134 const char *key)
1135 {
1136 DBusHashEntry *entry;
1137 DBusHashEntry **bucket;
1138
1139 _dbus_assert (table->key_type == DBUS_HASH_STRING);
1140
1141 entry = (* table->find_function) (table, (char*) key, FALSE, &bucket, NULL);
1142
1143 if (entry)
1144 {
1145 remove_entry (table, bucket, entry);
1146 return TRUE;
1147 }
1148 else
1149 return FALSE;
1150 }
1151
1152 /**
1153 * Removes the hash entry for the given key. If no hash entry
1154 * for the key exists, does nothing.
1155 *
1156 * @param table the hash table.
1157 * @param key the hash key.
1158 * @returns #TRUE if the entry existed
1159 */
1160 dbus_bool_t
_dbus_hash_table_remove_int(DBusHashTable * table,int key)1161 _dbus_hash_table_remove_int (DBusHashTable *table,
1162 int key)
1163 {
1164 DBusHashEntry *entry;
1165 DBusHashEntry **bucket;
1166
1167 _dbus_assert (table->key_type == DBUS_HASH_INT);
1168
1169 entry = (* table->find_function) (table, _DBUS_INT_TO_POINTER (key), FALSE, &bucket, NULL);
1170
1171 if (entry)
1172 {
1173 remove_entry (table, bucket, entry);
1174 return TRUE;
1175 }
1176 else
1177 return FALSE;
1178 }
1179
1180 /**
1181 * Removes the hash entry for the given key. If no hash entry
1182 * for the key exists, does nothing.
1183 *
1184 * @param table the hash table.
1185 * @param key the hash key.
1186 * @returns #TRUE if the entry existed
1187 */
1188 dbus_bool_t
_dbus_hash_table_remove_uintptr(DBusHashTable * table,uintptr_t key)1189 _dbus_hash_table_remove_uintptr (DBusHashTable *table,
1190 uintptr_t key)
1191 {
1192 DBusHashEntry *entry;
1193 DBusHashEntry **bucket;
1194
1195 _dbus_assert (table->key_type == DBUS_HASH_UINTPTR);
1196
1197 entry = (* table->find_function) (table, (void*) key, FALSE, &bucket, NULL);
1198
1199 if (entry)
1200 {
1201 remove_entry (table, bucket, entry);
1202 return TRUE;
1203 }
1204 else
1205 return FALSE;
1206 }
1207
1208 /**
1209 * Creates a hash entry with the given key and value.
1210 * The key and value are not copied; they are stored
1211 * in the hash table by reference. If an entry with the
1212 * given key already exists, the previous key and value
1213 * are overwritten (and freed if the hash table has
1214 * a key_free_function and/or value_free_function).
1215 *
1216 * Returns #FALSE if memory for the new hash entry
1217 * can't be allocated.
1218 *
1219 * @param table the hash table.
1220 * @param key the hash entry key.
1221 * @param value the hash entry value.
1222 */
1223 dbus_bool_t
_dbus_hash_table_insert_string(DBusHashTable * table,char * key,void * value)1224 _dbus_hash_table_insert_string (DBusHashTable *table,
1225 char *key,
1226 void *value)
1227 {
1228 DBusPreallocatedHash *preallocated;
1229
1230 _dbus_assert (table->key_type == DBUS_HASH_STRING);
1231
1232 preallocated = _dbus_hash_table_preallocate_entry (table);
1233 if (preallocated == NULL)
1234 return FALSE;
1235
1236 _dbus_hash_table_insert_string_preallocated (table, preallocated,
1237 key, value);
1238
1239 return TRUE;
1240 }
1241
1242 /**
1243 * Creates a hash entry with the given key and value.
1244 * The key and value are not copied; they are stored
1245 * in the hash table by reference. If an entry with the
1246 * given key already exists, the previous key and value
1247 * are overwritten (and freed if the hash table has
1248 * a key_free_function and/or value_free_function).
1249 *
1250 * Returns #FALSE if memory for the new hash entry
1251 * can't be allocated.
1252 *
1253 * @param table the hash table.
1254 * @param key the hash entry key.
1255 * @param value the hash entry value.
1256 */
1257 dbus_bool_t
_dbus_hash_table_insert_int(DBusHashTable * table,int key,void * value)1258 _dbus_hash_table_insert_int (DBusHashTable *table,
1259 int key,
1260 void *value)
1261 {
1262 DBusHashEntry *entry;
1263
1264 _dbus_assert (table->key_type == DBUS_HASH_INT);
1265
1266 entry = (* table->find_function) (table, _DBUS_INT_TO_POINTER (key), TRUE, NULL, NULL);
1267
1268 if (entry == NULL)
1269 return FALSE; /* no memory */
1270
1271 if (table->free_key_function && entry->key != _DBUS_INT_TO_POINTER (key))
1272 (* table->free_key_function) (entry->key);
1273
1274 if (table->free_value_function && entry->value != value)
1275 (* table->free_value_function) (entry->value);
1276
1277 entry->key = _DBUS_INT_TO_POINTER (key);
1278 entry->value = value;
1279
1280 return TRUE;
1281 }
1282
1283 /**
1284 * Creates a hash entry with the given key and value.
1285 * The key and value are not copied; they are stored
1286 * in the hash table by reference. If an entry with the
1287 * given key already exists, the previous key and value
1288 * are overwritten (and freed if the hash table has
1289 * a key_free_function and/or value_free_function).
1290 *
1291 * Returns #FALSE if memory for the new hash entry
1292 * can't be allocated.
1293 *
1294 * @param table the hash table.
1295 * @param key the hash entry key.
1296 * @param value the hash entry value.
1297 */
1298 dbus_bool_t
_dbus_hash_table_insert_uintptr(DBusHashTable * table,uintptr_t key,void * value)1299 _dbus_hash_table_insert_uintptr (DBusHashTable *table,
1300 uintptr_t key,
1301 void *value)
1302 {
1303 DBusHashEntry *entry;
1304
1305 _dbus_assert (table->key_type == DBUS_HASH_UINTPTR);
1306
1307 entry = (* table->find_function) (table, (void*) key, TRUE, NULL, NULL);
1308
1309 if (entry == NULL)
1310 return FALSE; /* no memory */
1311
1312 if (table->free_key_function && entry->key != (void*) key)
1313 (* table->free_key_function) (entry->key);
1314
1315 if (table->free_value_function && entry->value != value)
1316 (* table->free_value_function) (entry->value);
1317
1318 entry->key = (void*) key;
1319 entry->value = value;
1320
1321 return TRUE;
1322 }
1323
1324 /**
1325 * Preallocate an opaque data blob that allows us to insert into the
1326 * hash table at a later time without allocating any memory.
1327 *
1328 * @param table the hash table
1329 * @returns the preallocated data, or #NULL if no memory
1330 */
1331 DBusPreallocatedHash*
_dbus_hash_table_preallocate_entry(DBusHashTable * table)1332 _dbus_hash_table_preallocate_entry (DBusHashTable *table)
1333 {
1334 DBusHashEntry *entry;
1335
1336 entry = alloc_entry (table);
1337
1338 return (DBusPreallocatedHash*) entry;
1339 }
1340
1341 /**
1342 * Frees an opaque DBusPreallocatedHash that was *not* used
1343 * in order to insert into the hash table.
1344 *
1345 * @param table the hash table
1346 * @param preallocated the preallocated data
1347 */
1348 void
_dbus_hash_table_free_preallocated_entry(DBusHashTable * table,DBusPreallocatedHash * preallocated)1349 _dbus_hash_table_free_preallocated_entry (DBusHashTable *table,
1350 DBusPreallocatedHash *preallocated)
1351 {
1352 DBusHashEntry *entry;
1353
1354 _dbus_assert (preallocated != NULL);
1355
1356 entry = (DBusHashEntry*) preallocated;
1357
1358 /* Don't use free_entry(), since this entry has no key/data */
1359 _dbus_mem_pool_dealloc (table->entry_pool, entry);
1360 }
1361
1362 /**
1363 * Inserts a string-keyed entry into the hash table, using a
1364 * preallocated data block from
1365 * _dbus_hash_table_preallocate_entry(). This function cannot fail due
1366 * to lack of memory. The DBusPreallocatedHash object is consumed and
1367 * should not be reused or freed. Otherwise this function works
1368 * just like _dbus_hash_table_insert_string().
1369 *
1370 * @param table the hash table
1371 * @param preallocated the preallocated data
1372 * @param key the hash key
1373 * @param value the value
1374 */
1375 void
_dbus_hash_table_insert_string_preallocated(DBusHashTable * table,DBusPreallocatedHash * preallocated,char * key,void * value)1376 _dbus_hash_table_insert_string_preallocated (DBusHashTable *table,
1377 DBusPreallocatedHash *preallocated,
1378 char *key,
1379 void *value)
1380 {
1381 DBusHashEntry *entry;
1382
1383 _dbus_assert (table->key_type == DBUS_HASH_STRING);
1384 _dbus_assert (preallocated != NULL);
1385
1386 entry = (* table->find_function) (table, key, TRUE, NULL, preallocated);
1387
1388 _dbus_assert (entry != NULL);
1389
1390 if (table->free_key_function && entry->key != key)
1391 (* table->free_key_function) (entry->key);
1392
1393 if (table->free_value_function && entry->value != value)
1394 (* table->free_value_function) (entry->value);
1395
1396 entry->key = key;
1397 entry->value = value;
1398 }
1399
1400 /**
1401 * Gets the number of hash entries in a hash table.
1402 *
1403 * @param table the hash table.
1404 * @returns the number of entries in the table.
1405 */
1406 int
_dbus_hash_table_get_n_entries(DBusHashTable * table)1407 _dbus_hash_table_get_n_entries (DBusHashTable *table)
1408 {
1409 return table->n_entries;
1410 }
1411
1412 /**
1413 * Imports a string array into a hash table
1414 * The hash table needs to be initialized with string keys,
1415 * and dbus_free() as both key and value free-function.
1416 *
1417 * @param table the hash table
1418 * @param array the string array to import
1419 * @param delimiter the delimiter to separate key and value
1420 * @return #TRUE on success.
1421 * @return #FALSE if not enough memory.
1422 */
1423
1424 dbus_bool_t
_dbus_hash_table_from_array(DBusHashTable * table,char ** array,char delimiter)1425 _dbus_hash_table_from_array (DBusHashTable *table, char **array, char delimiter)
1426 {
1427 DBusString key;
1428 DBusString value;
1429 int i;
1430 dbus_bool_t retval = FALSE;
1431
1432 _dbus_assert (table != NULL);
1433 _dbus_assert (array != NULL);
1434
1435 if (!_dbus_string_init (&key))
1436 {
1437 return FALSE;
1438 }
1439
1440 if (!_dbus_string_init (&value))
1441 {
1442 _dbus_string_free (&key);
1443 return FALSE;
1444 }
1445
1446 for (i = 0; array[i] != NULL; i++)
1447 {
1448 if (!_dbus_string_append (&key, array[i]))
1449 break;
1450
1451 if (_dbus_string_split_on_byte (&key, delimiter, &value))
1452 {
1453 char *hash_key, *hash_value;
1454
1455 if (!_dbus_string_steal_data (&key, &hash_key))
1456 break;
1457
1458 if (!_dbus_string_steal_data (&value, &hash_value))
1459 break;
1460
1461 if (!_dbus_hash_table_insert_string (table,
1462 hash_key, hash_value))
1463 break;
1464 }
1465 _dbus_string_set_length (&key, 0);
1466 _dbus_string_set_length (&value, 0);
1467 }
1468
1469 if (array[i] != NULL)
1470 goto out;
1471
1472 retval = TRUE;
1473 out:
1474
1475 _dbus_string_free (&key);
1476 _dbus_string_free (&value);
1477
1478 return retval;
1479 }
1480
1481 /**
1482 * Creates a string array from a hash table
1483 *
1484 * @param table the hash table
1485 * @param delimiter the delimiter to join key and value
1486 * @return pointer to created string array (free with dbus_free_string_array)
1487 * @return #FALSE if not enough memory.
1488 */
1489 char **
_dbus_hash_table_to_array(DBusHashTable * table,char delimiter)1490 _dbus_hash_table_to_array (DBusHashTable *table, char delimiter)
1491 {
1492 int i, length;
1493 DBusString entry;
1494 DBusHashIter iter;
1495 char **array;
1496
1497 _dbus_assert (table != NULL);
1498
1499 length = _dbus_hash_table_get_n_entries (table);
1500
1501 array = dbus_new0 (char *, length + 1);
1502
1503 if (array == NULL)
1504 return NULL;
1505
1506 i = 0;
1507 _dbus_hash_iter_init (table, &iter);
1508
1509 if (!_dbus_string_init (&entry))
1510 {
1511 dbus_free_string_array (array);
1512 return NULL;
1513 }
1514
1515 while (_dbus_hash_iter_next (&iter))
1516 {
1517 const char *key, *value;
1518
1519 key = (const char *) _dbus_hash_iter_get_string_key (&iter);
1520 value = (const char *) _dbus_hash_iter_get_value (&iter);
1521
1522 if (!_dbus_string_append_printf (&entry, "%s%c%s", key, delimiter, value))
1523 break;
1524
1525 if (!_dbus_string_steal_data (&entry, array + i))
1526 break;
1527 i++;
1528 }
1529
1530 _dbus_string_free (&entry);
1531
1532 if (i != length)
1533 {
1534 dbus_free_string_array (array);
1535 array = NULL;
1536 }
1537
1538 return array;
1539 }
1540
1541 /** @} */
1542
1543 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
1544 #include "dbus-test.h"
1545 #include <stdio.h>
1546
1547 /* If you're wondering why the hash table test takes
1548 * forever to run, it's because we call this function
1549 * in inner loops thus making things quadratic.
1550 */
1551 static int
count_entries(DBusHashTable * table)1552 count_entries (DBusHashTable *table)
1553 {
1554 DBusHashIter iter;
1555 int count;
1556
1557 count = 0;
1558 _dbus_hash_iter_init (table, &iter);
1559 while (_dbus_hash_iter_next (&iter))
1560 ++count;
1561
1562 _dbus_assert (count == _dbus_hash_table_get_n_entries (table));
1563
1564 return count;
1565 }
1566
1567 static inline void *
steal(void * ptr)1568 steal (void *ptr)
1569 {
1570 /* @ptr is passed in as void* to avoid casting in the call */
1571 void **_ptr = (void **) ptr;
1572 void *val;
1573
1574 val = *_ptr;
1575 *_ptr = NULL;
1576
1577 return val;
1578 }
1579
1580 /**
1581 * @ingroup DBusHashTableInternals
1582 * Unit test for DBusHashTable
1583 * @returns #TRUE on success.
1584 */
1585 dbus_bool_t
_dbus_hash_test(void)1586 _dbus_hash_test (void)
1587 {
1588 int i;
1589 DBusHashTable *table1;
1590 DBusHashTable *table2;
1591 DBusHashTable *table3;
1592 DBusHashIter iter;
1593 #define N_HASH_KEYS 5000
1594 char **keys;
1595 dbus_bool_t ret = FALSE;
1596 char *str_key = NULL;
1597 char *str_value = NULL;
1598
1599 keys = dbus_new (char *, N_HASH_KEYS);
1600 if (keys == NULL)
1601 _dbus_assert_not_reached ("no memory");
1602
1603 for (i = 0; i < N_HASH_KEYS; i++)
1604 {
1605 keys[i] = dbus_malloc (128);
1606
1607 if (keys[i] == NULL)
1608 _dbus_assert_not_reached ("no memory");
1609 }
1610
1611 printf ("Computing test hash keys...\n");
1612 i = 0;
1613 while (i < N_HASH_KEYS)
1614 {
1615 int len;
1616
1617 len = sprintf (keys[i], "Hash key %d", i);
1618 _dbus_assert (*(keys[i] + len) == '\0');
1619 ++i;
1620 }
1621 printf ("... done.\n");
1622
1623 table1 = _dbus_hash_table_new (DBUS_HASH_STRING,
1624 dbus_free, dbus_free);
1625 if (table1 == NULL)
1626 goto out;
1627
1628 table2 = _dbus_hash_table_new (DBUS_HASH_INT,
1629 NULL, dbus_free);
1630 if (table2 == NULL)
1631 goto out;
1632
1633 table3 = _dbus_hash_table_new (DBUS_HASH_UINTPTR,
1634 NULL, dbus_free);
1635 if (table3 == NULL)
1636 goto out;
1637
1638 /* Insert and remove a bunch of stuff, counting the table in between
1639 * to be sure it's not broken and that iteration works
1640 */
1641 i = 0;
1642 while (i < 3000)
1643 {
1644 const void *out_value;
1645
1646 str_key = _dbus_strdup (keys[i]);
1647 if (str_key == NULL)
1648 goto out;
1649 str_value = _dbus_strdup ("Value!");
1650 if (str_value == NULL)
1651 goto out;
1652
1653 if (!_dbus_hash_table_insert_string (table1,
1654 steal (&str_key),
1655 steal (&str_value)))
1656 goto out;
1657
1658 str_value = _dbus_strdup (keys[i]);
1659 if (str_value == NULL)
1660 goto out;
1661
1662 if (!_dbus_hash_table_insert_int (table2,
1663 i, steal (&str_value)))
1664 goto out;
1665
1666 str_value = _dbus_strdup (keys[i]);
1667 if (str_value == NULL)
1668 goto out;
1669
1670 if (!_dbus_hash_table_insert_uintptr (table3,
1671 i, steal (&str_value)))
1672 goto out;
1673
1674 _dbus_assert (count_entries (table1) == i + 1);
1675 _dbus_assert (count_entries (table2) == i + 1);
1676 _dbus_assert (count_entries (table3) == i + 1);
1677
1678 out_value = _dbus_hash_table_lookup_string (table1, keys[i]);
1679 _dbus_assert (out_value != NULL);
1680 _dbus_assert (strcmp (out_value, "Value!") == 0);
1681
1682 out_value = _dbus_hash_table_lookup_int (table2, i);
1683 _dbus_assert (out_value != NULL);
1684 _dbus_assert (strcmp (out_value, keys[i]) == 0);
1685
1686 out_value = _dbus_hash_table_lookup_uintptr (table3, i);
1687 _dbus_assert (out_value != NULL);
1688 _dbus_assert (strcmp (out_value, keys[i]) == 0);
1689
1690 ++i;
1691 }
1692
1693 --i;
1694 while (i >= 0)
1695 {
1696 _dbus_hash_table_remove_string (table1,
1697 keys[i]);
1698
1699 _dbus_hash_table_remove_int (table2, i);
1700
1701 _dbus_hash_table_remove_uintptr (table3, i);
1702
1703 _dbus_assert (count_entries (table1) == i);
1704 _dbus_assert (count_entries (table2) == i);
1705 _dbus_assert (count_entries (table3) == i);
1706
1707 --i;
1708 }
1709
1710 _dbus_hash_table_ref (table1);
1711 _dbus_hash_table_ref (table2);
1712 _dbus_hash_table_ref (table3);
1713 _dbus_hash_table_unref (table1);
1714 _dbus_hash_table_unref (table2);
1715 _dbus_hash_table_unref (table3);
1716 _dbus_hash_table_unref (table1);
1717 _dbus_hash_table_unref (table2);
1718 _dbus_hash_table_unref (table3);
1719 table3 = NULL;
1720
1721 /* Insert a bunch of stuff then check
1722 * that iteration works correctly (finds the right
1723 * values, iter_set_value works, etc.)
1724 */
1725 table1 = _dbus_hash_table_new (DBUS_HASH_STRING,
1726 dbus_free, dbus_free);
1727 if (table1 == NULL)
1728 goto out;
1729
1730 table2 = _dbus_hash_table_new (DBUS_HASH_INT,
1731 NULL, dbus_free);
1732 if (table2 == NULL)
1733 goto out;
1734
1735 i = 0;
1736 while (i < 5000)
1737 {
1738 str_key = _dbus_strdup (keys[i]);
1739 if (str_key == NULL)
1740 goto out;
1741 str_value = _dbus_strdup ("Value!");
1742 if (str_value == NULL)
1743 goto out;
1744
1745 if (!_dbus_hash_table_insert_string (table1,
1746 steal (&str_key),
1747 steal (&str_value)))
1748 goto out;
1749
1750 str_value = _dbus_strdup (keys[i]);
1751 if (str_value == NULL)
1752 goto out;
1753
1754 if (!_dbus_hash_table_insert_int (table2,
1755 i, steal (&str_value)))
1756 goto out;
1757
1758 _dbus_assert (count_entries (table1) == i + 1);
1759 _dbus_assert (count_entries (table2) == i + 1);
1760
1761 ++i;
1762 }
1763
1764 _dbus_hash_iter_init (table1, &iter);
1765 while (_dbus_hash_iter_next (&iter))
1766 {
1767 const char *key;
1768 const void *value;
1769
1770 key = _dbus_hash_iter_get_string_key (&iter);
1771 value = _dbus_hash_iter_get_value (&iter);
1772
1773 _dbus_assert (_dbus_hash_table_lookup_string (table1, key) == value);
1774
1775 str_value = _dbus_strdup ("Different value!");
1776 if (str_value == NULL)
1777 goto out;
1778
1779 value = str_value;
1780 _dbus_hash_iter_set_value (&iter, steal (&str_value));
1781 _dbus_assert (_dbus_hash_table_lookup_string (table1, key) == value);
1782 }
1783
1784 _dbus_hash_iter_init (table1, &iter);
1785 while (_dbus_hash_iter_next (&iter))
1786 {
1787 _dbus_hash_iter_remove_entry (&iter);
1788 _dbus_assert (count_entries (table1) == i - 1);
1789 --i;
1790 }
1791
1792 _dbus_hash_iter_init (table2, &iter);
1793 while (_dbus_hash_iter_next (&iter))
1794 {
1795 int key;
1796 const void *value;
1797
1798 key = _dbus_hash_iter_get_int_key (&iter);
1799 value = _dbus_hash_iter_get_value (&iter);
1800
1801 _dbus_assert (_dbus_hash_table_lookup_int (table2, key) == value);
1802
1803 str_value = _dbus_strdup ("Different value!");
1804 if (str_value == NULL)
1805 goto out;
1806
1807 value = str_value;
1808 _dbus_hash_iter_set_value (&iter, steal (&str_value));
1809 _dbus_assert (_dbus_hash_table_lookup_int (table2, key) == value);
1810 }
1811
1812 i = count_entries (table2);
1813 _dbus_hash_iter_init (table2, &iter);
1814 while (_dbus_hash_iter_next (&iter))
1815 {
1816 _dbus_hash_iter_remove_entry (&iter);
1817 _dbus_assert (count_entries (table2) + 1 == i);
1818 --i;
1819 }
1820
1821 /* add/remove interleaved, to check that we grow/shrink the table
1822 * appropriately
1823 */
1824 i = 0;
1825 while (i < 1000)
1826 {
1827 str_key = _dbus_strdup (keys[i]);
1828 if (str_key == NULL)
1829 goto out;
1830
1831 str_value = _dbus_strdup ("Value!");
1832 if (str_value == NULL)
1833 goto out;
1834
1835 if (!_dbus_hash_table_insert_string (table1,
1836 steal (&str_key),
1837 steal (&str_value)))
1838 goto out;
1839
1840 ++i;
1841 }
1842
1843 --i;
1844 while (i >= 0)
1845 {
1846 str_key = _dbus_strdup (keys[i]);
1847 if (str_key == NULL)
1848 goto out;
1849 str_value = _dbus_strdup ("Value!");
1850 if (str_value == NULL)
1851 goto out;
1852
1853 if (!_dbus_hash_table_remove_string (table1, keys[i]))
1854 goto out;
1855
1856 if (!_dbus_hash_table_insert_string (table1,
1857 steal (&str_key),
1858 steal (&str_value)))
1859 goto out;
1860
1861 if (!_dbus_hash_table_remove_string (table1, keys[i]))
1862 goto out;
1863
1864 _dbus_assert (_dbus_hash_table_get_n_entries (table1) == i);
1865
1866 --i;
1867 }
1868
1869 /* nuke these tables */
1870 _dbus_hash_table_unref (table1);
1871 _dbus_hash_table_unref (table2);
1872
1873
1874 /* Now do a bunch of things again using _dbus_hash_iter_lookup() to
1875 * be sure that interface works.
1876 */
1877 table1 = _dbus_hash_table_new (DBUS_HASH_STRING,
1878 dbus_free, dbus_free);
1879 if (table1 == NULL)
1880 goto out;
1881
1882 table2 = _dbus_hash_table_new (DBUS_HASH_INT,
1883 NULL, dbus_free);
1884 if (table2 == NULL)
1885 goto out;
1886
1887 i = 0;
1888 while (i < 3000)
1889 {
1890 const void *out_value;
1891
1892 str_key = _dbus_strdup (keys[i]);
1893 if (str_key == NULL)
1894 goto out;
1895 str_value = _dbus_strdup ("Value!");
1896 if (str_value == NULL)
1897 goto out;
1898
1899 if (!_dbus_hash_iter_lookup (table1,
1900 steal (&str_key), TRUE, &iter))
1901 goto out;
1902 _dbus_assert (_dbus_hash_iter_get_value (&iter) == NULL);
1903 _dbus_hash_iter_set_value (&iter, steal (&str_value));
1904
1905 str_value = _dbus_strdup (keys[i]);
1906 if (str_value == NULL)
1907 goto out;
1908
1909 if (!_dbus_hash_iter_lookup (table2,
1910 _DBUS_INT_TO_POINTER (i), TRUE, &iter))
1911 goto out;
1912 _dbus_assert (_dbus_hash_iter_get_value (&iter) == NULL);
1913 _dbus_hash_iter_set_value (&iter, steal (&str_value));
1914
1915 _dbus_assert (count_entries (table1) == i + 1);
1916 _dbus_assert (count_entries (table2) == i + 1);
1917
1918 if (!_dbus_hash_iter_lookup (table1, keys[i], FALSE, &iter))
1919 goto out;
1920
1921 out_value = _dbus_hash_iter_get_value (&iter);
1922 _dbus_assert (out_value != NULL);
1923 _dbus_assert (strcmp (out_value, "Value!") == 0);
1924
1925 /* Iterate just to be sure it works, though
1926 * it's a stupid thing to do
1927 */
1928 while (_dbus_hash_iter_next (&iter))
1929 ;
1930
1931 if (!_dbus_hash_iter_lookup (table2, _DBUS_INT_TO_POINTER (i), FALSE, &iter))
1932 goto out;
1933
1934 out_value = _dbus_hash_iter_get_value (&iter);
1935 _dbus_assert (out_value != NULL);
1936 _dbus_assert (strcmp (out_value, keys[i]) == 0);
1937
1938 /* Iterate just to be sure it works, though
1939 * it's a stupid thing to do
1940 */
1941 while (_dbus_hash_iter_next (&iter))
1942 ;
1943
1944 ++i;
1945 }
1946
1947 --i;
1948 while (i >= 0)
1949 {
1950 if (!_dbus_hash_iter_lookup (table1, keys[i], FALSE, &iter))
1951 _dbus_assert_not_reached ("hash entry should have existed");
1952 _dbus_hash_iter_remove_entry (&iter);
1953
1954 if (!_dbus_hash_iter_lookup (table2, _DBUS_INT_TO_POINTER (i), FALSE, &iter))
1955 _dbus_assert_not_reached ("hash entry should have existed");
1956 _dbus_hash_iter_remove_entry (&iter);
1957
1958 _dbus_assert (count_entries (table1) == i);
1959 _dbus_assert (count_entries (table2) == i);
1960
1961 --i;
1962 }
1963
1964 _dbus_hash_table_unref (table1);
1965 _dbus_hash_table_unref (table2);
1966
1967 ret = TRUE;
1968
1969 out:
1970 for (i = 0; i < N_HASH_KEYS; i++)
1971 dbus_free (keys[i]);
1972
1973 dbus_free (keys);
1974
1975 dbus_free (str_key);
1976 dbus_free (str_value);
1977
1978 return ret;
1979 }
1980
1981 #endif /* DBUS_ENABLE_EMBEDDED_TESTS */
1982