1 /* -*- mode: C; c-file-style: "gnu" -*- */
2 /* dbus-hash.c Generic hash table utility (internal to D-BUS implementation)
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.
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.
13 * Licensed under the Academic Free License version 1.2
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.
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.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
31 * The following copyright applies to code from the Tcl distribution.
33 * Copyright (c) 1991-1993 The Regents of the University of California.
34 * Copyright (c) 1994 Sun Microsystems, Inc.
36 * This software is copyrighted by the Regents of the University of
37 * California, Sun Microsystems, Inc., Scriptics Corporation, and
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77 #include "dbus-hash.h"
78 #include "dbus-internals.h"
79 #include "dbus-mempool.h"
82 * @defgroup DBusHashTable Hash table
83 * @ingroup DBusInternals
84 * @brief DBusHashTable data structure
86 * Types and functions related to DBusHashTable.
90 * @defgroup DBusHashTableInternals Hash table implementation details
91 * @ingroup DBusInternals
92 * @brief DBusHashTable implementation details
94 * The guts of DBusHashTable.
100 * When there are this many entries per bucket, on average, rebuild
101 * the hash table to make it larger.
103 #define REBUILD_MULTIPLIER 3
106 * Takes a preliminary integer hash value and produces an index into a
107 * hash tables bucket list. The idea is to make it so that
108 * preliminary values that are arbitrarily similar will end up in
109 * different buckets. The hash function was taken from a
110 * random-number generator. (This is used to hash integers.)
112 * The down_shift drops off the high bits of the hash index, and
113 * decreases as we increase the number of hash buckets (to keep more
114 * range in the hash index). The mask also strips high bits and strips
115 * fewer high bits as the number of hash buckets increases.
116 * I don't understand two things: why is the initial downshift 28
117 * to keep 4 bits when the initial mask is 011 to keep 2 bits,
118 * and why do we have both a mask and a downshift?
121 #define RANDOM_INDEX(table, i) \
122 (((((long) (i))*1103515245) >> (table)->down_shift) & (table)->mask)
125 * Initial number of buckets in hash table (hash table statically
126 * allocates its buckets for this size and below).
127 * The initial mask has to be synced to this.
129 #define DBUS_SMALL_HASH_TABLE 4
132 * Typedef for DBusHashEntry
134 typedef struct DBusHashEntry DBusHashEntry;
137 * @brief Internal representation of a hash entry.
139 * A single entry (key-value pair) in the hash table.
140 * Internal to hash table implementation.
144 DBusHashEntry *next; /**< Pointer to next entry in this
145 * hash bucket, or #NULL for end of
148 void *key; /**< Hash key */
149 void *value; /**< Hash value */
153 * Function used to find and optionally create a hash entry.
155 typedef DBusHashEntry* (* DBusFindEntryFunction) (DBusHashTable *table,
157 dbus_bool_t create_if_not_found,
158 DBusHashEntry ***bucket);
161 * @brief Internals of DBusHashTable.
163 * Hash table internals. Hash tables are opaque objects, they must be
164 * used via accessor functions.
166 struct DBusHashTable {
167 int refcount; /**< Reference count */
169 DBusHashEntry **buckets; /**< Pointer to bucket array. Each
170 * element points to first entry in
171 * bucket's hash chain, or #NULL.
173 DBusHashEntry *static_buckets[DBUS_SMALL_HASH_TABLE];
174 /**< Bucket array used for small tables
175 * (to avoid mallocs and frees).
177 int n_buckets; /**< Total number of buckets allocated
180 int n_entries; /**< Total number of entries present
183 int hi_rebuild_size; /**< Enlarge table when n_entries gets
186 int lo_rebuild_size; /**< Shrink table when n_entries gets
189 int down_shift; /**< Shift count used in hashing
190 * function. Designed to use high-
191 * order bits of randomized keys.
193 int mask; /**< Mask value used in hashing
196 DBusHashType key_type; /**< Type of keys used in this table */
199 DBusFindEntryFunction find_function; /**< Function for finding entries */
201 DBusFreeFunction free_key_function; /**< Function to free keys */
202 DBusFreeFunction free_value_function; /**< Function to free values */
204 DBusMemPool *entry_pool; /**< Memory pool for hash entries */
208 * @brief Internals of DBusHashIter.
212 DBusHashTable *table; /**< Pointer to table containing entry. */
213 DBusHashEntry **bucket; /**< Pointer to bucket that points to
214 * first entry in this entry's chain:
215 * used for deleting the entry.
217 DBusHashEntry *entry; /**< Current hash entry */
218 DBusHashEntry *next_entry; /**< Next entry to be iterated onto in current bucket */
219 int next_bucket; /**< index of next bucket */
220 int n_entries_on_init; /**< used to detect table resize since initialization */
223 static DBusHashEntry* find_direct_function (DBusHashTable *table,
225 dbus_bool_t create_if_not_found,
226 DBusHashEntry ***bucket);
227 static DBusHashEntry* find_string_function (DBusHashTable *table,
229 dbus_bool_t create_if_not_found,
230 DBusHashEntry ***bucket);
231 static unsigned int string_hash (const char *str);
232 static void rebuild_table (DBusHashTable *table);
233 static DBusHashEntry* alloc_entry (DBusHashTable *table);
234 static void remove_entry (DBusHashTable *table,
235 DBusHashEntry **bucket,
236 DBusHashEntry *entry);
237 static void free_entry (DBusHashTable *table,
238 DBusHashEntry *entry);
243 * @addtogroup DBusHashTable
248 * @typedef DBusHashIter
250 * Public opaque hash table iterator object.
254 * @typedef DBusHashTable
256 * Public opaque hash table object.
260 * @typedef DBusHashType
262 * Indicates the type of a key in the hash table.
266 * Constructs a new hash table. Should be freed with
267 * _dbus_hash_table_unref(). If memory cannot be
268 * allocated for the hash table, returns #NULL.
270 * @param type the type of hash key to use.
271 * @param key_free_function function to free hash keys.
272 * @param value_free_function function to free hash values.
273 * @returns a new DBusHashTable or #NULL if no memory.
276 _dbus_hash_table_new (DBusHashType type,
277 DBusFreeFunction key_free_function,
278 DBusFreeFunction value_free_function)
280 DBusHashTable *table;
281 DBusMemPool *entry_pool;
283 table = dbus_new0 (DBusHashTable, 1);
287 entry_pool = _dbus_mem_pool_new (sizeof (DBusHashEntry), TRUE);
288 if (entry_pool == NULL)
295 table->entry_pool = entry_pool;
297 _dbus_assert (DBUS_SMALL_HASH_TABLE == _DBUS_N_ELEMENTS (table->static_buckets));
299 table->buckets = table->static_buckets;
300 table->n_buckets = DBUS_SMALL_HASH_TABLE;
301 table->n_entries = 0;
302 table->hi_rebuild_size = DBUS_SMALL_HASH_TABLE * REBUILD_MULTIPLIER;
303 table->lo_rebuild_size = 0;
304 table->down_shift = 28;
306 table->key_type = type;
308 _dbus_assert (table->mask < table->n_buckets);
310 switch (table->key_type)
313 case DBUS_HASH_POINTER:
314 table->find_function = find_direct_function;
316 case DBUS_HASH_STRING:
317 table->find_function = find_string_function;
320 _dbus_assert_not_reached ("Unknown hash table type");
324 table->free_key_function = key_free_function;
325 table->free_value_function = value_free_function;
332 * Increments the reference count for a hash table.
334 * @param table the hash table to add a reference to.
337 _dbus_hash_table_ref (DBusHashTable *table)
339 table->refcount += 1;
343 * Decrements the reference count for a hash table,
344 * freeing the hash table if the count reaches zero.
346 * @param table the hash table to remove a reference from.
349 _dbus_hash_table_unref (DBusHashTable *table)
351 table->refcount -= 1;
353 if (table->refcount == 0)
356 DBusHashEntry *entry;
360 /* Free the entries in the table. */
361 for (i = 0; i < table->n_buckets; i++)
363 entry = table->buckets[i];
364 while (entry != NULL)
368 free_entry (table, entry);
374 /* We can do this very quickly with memory pools ;-) */
375 _dbus_mem_pool_free (table->entry_pool);
378 /* Free the bucket array, if it was dynamically allocated. */
379 if (table->buckets != table->static_buckets)
380 dbus_free (table->buckets);
386 static DBusHashEntry*
387 alloc_entry (DBusHashTable *table)
389 DBusHashEntry *entry;
391 entry = _dbus_mem_pool_alloc (table->entry_pool);
397 free_entry (DBusHashTable *table,
398 DBusHashEntry *entry)
400 if (table->free_key_function)
401 (* table->free_key_function) (entry->key);
402 if (table->free_value_function)
403 (* table->free_value_function) (entry->value);
405 _dbus_mem_pool_dealloc (table->entry_pool, entry);
409 remove_entry (DBusHashTable *table,
410 DBusHashEntry **bucket,
411 DBusHashEntry *entry)
413 _dbus_assert (table != NULL);
414 _dbus_assert (bucket != NULL);
415 _dbus_assert (*bucket != NULL);
416 _dbus_assert (entry != NULL);
418 if (*bucket == entry)
419 *bucket = entry->next;
425 while (prev->next != entry)
428 _dbus_assert (prev != NULL);
430 prev->next = entry->next;
433 table->n_entries -= 1;
434 free_entry (table, entry);
438 * Initializes a hash table iterator. To iterate over all entries in a
439 * hash table, use the following code (the printf assumes a hash
440 * from strings to strings obviously):
445 * _dbus_hash_iter_init (table, &iter);
446 * while (_dbus_hash_iter_next (&iter))
448 * printf ("The first key is %s and value is %s\n",
449 * _dbus_hash_iter_get_string_key (&iter),
450 * _dbus_hash_iter_get_value (&iter));
456 * The iterator is initialized pointing "one before" the first hash
457 * entry. The first call to _dbus_hash_iter_next() moves it onto
458 * the first valid entry or returns #FALSE if the hash table is
459 * empty. Subsequent calls move to the next valid entry or return
460 * #FALSE if there are no more entries.
462 * Note that it is guaranteed to be safe to remove a hash entry during
463 * iteration, but it is not safe to add a hash entry.
465 * @param table the hash table to iterate over.
466 * @param iter the iterator to initialize.
469 _dbus_hash_iter_init (DBusHashTable *table,
472 DBusRealHashIter *real;
474 _dbus_assert (sizeof (DBusHashIter) == sizeof (DBusRealHashIter));
476 real = (DBusRealHashIter*) iter;
481 real->next_entry = NULL;
482 real->next_bucket = 0;
483 real->n_entries_on_init = table->n_entries;
487 * Move the hash iterator forward one step, to the next hash entry.
488 * The documentation for _dbus_hash_iter_init() explains in more
491 * @param iter the iterator to move forward.
492 * @returns #FALSE if there are no more entries to move to.
495 _dbus_hash_iter_next (DBusHashIter *iter)
497 DBusRealHashIter *real;
499 _dbus_assert (sizeof (DBusHashIter) == sizeof (DBusRealHashIter));
501 real = (DBusRealHashIter*) iter;
503 /* if this assertion failed someone probably added hash entries
504 * during iteration, which is bad.
506 _dbus_assert (real->n_entries_on_init >= real->table->n_entries);
508 /* Remember that real->entry may have been deleted */
510 while (real->next_entry == NULL)
512 if (real->next_bucket >= real->table->n_buckets)
514 /* invalidate iter and return false */
521 real->bucket = &(real->table->buckets[real->next_bucket]);
522 real->next_entry = *(real->bucket);
523 real->next_bucket += 1;
526 _dbus_assert (real->next_entry != NULL);
527 _dbus_assert (real->bucket != NULL);
529 real->entry = real->next_entry;
530 real->next_entry = real->entry->next;
536 * Removes the current entry from the hash table.
537 * If a key_free_function or value_free_function
538 * was provided to _dbus_hash_table_new(),
539 * frees the key and/or value for this entry.
541 * @param iter the hash table iterator.
544 _dbus_hash_iter_remove_entry (DBusHashIter *iter)
546 DBusRealHashIter *real;
548 real = (DBusRealHashIter*) iter;
550 _dbus_assert (real->table != NULL);
551 _dbus_assert (real->entry != NULL);
552 _dbus_assert (real->bucket != NULL);
554 remove_entry (real->table, real->bucket, real->entry);
556 real->entry = NULL; /* make it crash if you try to use this entry */
560 * Gets the value of the current entry.
562 * @param iter the hash table iterator.
565 _dbus_hash_iter_get_value (DBusHashIter *iter)
567 DBusRealHashIter *real;
569 real = (DBusRealHashIter*) iter;
571 _dbus_assert (real->table != NULL);
572 _dbus_assert (real->entry != NULL);
574 return real->entry->value;
578 * Sets the value of the current entry.
579 * If the hash table has a value_free_function
580 * it will be used to free the previous value.
581 * The hash table will own the passed-in value
582 * (it will not be copied).
584 * @param iter the hash table iterator.
585 * @param value the new value.
588 _dbus_hash_iter_set_value (DBusHashIter *iter,
591 DBusRealHashIter *real;
593 real = (DBusRealHashIter*) iter;
595 _dbus_assert (real->table != NULL);
596 _dbus_assert (real->entry != NULL);
598 if (real->table->free_value_function && value != real->entry->value)
599 (* real->table->free_value_function) (real->entry->value);
601 real->entry->value = value;
605 * Gets the key for the current entry.
606 * Only works for hash tables of type #DBUS_HASH_INT.
608 * @param iter the hash table iterator.
611 _dbus_hash_iter_get_int_key (DBusHashIter *iter)
613 DBusRealHashIter *real;
615 real = (DBusRealHashIter*) iter;
617 _dbus_assert (real->table != NULL);
618 _dbus_assert (real->entry != NULL);
620 return _DBUS_POINTER_TO_INT (real->entry->key);
624 * Gets the key for the current entry.
625 * Only works for hash tables of type #DBUS_HASH_STRING
626 * @param iter the hash table iterator.
629 _dbus_hash_iter_get_string_key (DBusHashIter *iter)
631 DBusRealHashIter *real;
633 real = (DBusRealHashIter*) iter;
635 _dbus_assert (real->table != NULL);
636 _dbus_assert (real->entry != NULL);
638 return real->entry->key;
642 * A low-level but efficient interface for manipulating the hash
643 * table. It's efficient because you can get, set, and optionally
644 * create the hash entry while only running the hash function one
647 * Note that while calling _dbus_hash_iter_next() on the iterator
648 * filled in by this function may work, it's completely
649 * undefined which entries are after this iter and which
650 * are before it. So it would be silly to iterate using this
653 * If the hash entry is created, its value will be initialized
656 * #FALSE may be returned due to memory allocation failure, or
657 * because create_if_not_found was #FALSE and the entry
660 * If create_if_not_found is #TRUE and the entry is created, the hash
661 * table takes ownership of the key that's passed in.
663 * For a hash table of type #DBUS_HASH_INT, cast the int
664 * key to the key parameter using #_DBUS_INT_TO_POINTER().
666 * @param table the hash table.
667 * @param key the hash key.
668 * @param create_if_not_found if #TRUE, create the entry if it didn't exist.
669 * @param iter the iterator to initialize.
670 * @returns #TRUE if the hash entry now exists (and the iterator is thus valid).
673 _dbus_hash_iter_lookup (DBusHashTable *table,
675 dbus_bool_t create_if_not_found,
678 DBusRealHashIter *real;
679 DBusHashEntry *entry;
680 DBusHashEntry **bucket;
682 _dbus_assert (sizeof (DBusHashIter) == sizeof (DBusRealHashIter));
684 real = (DBusRealHashIter*) iter;
686 entry = (* table->find_function) (table, key, create_if_not_found, &bucket);
692 real->bucket = bucket;
694 real->next_entry = entry->next;
695 real->next_bucket = (bucket - table->buckets) + 1;
696 real->n_entries_on_init = table->n_entries;
698 _dbus_assert (&(table->buckets[real->next_bucket-1]) == real->bucket);
703 static DBusHashEntry*
704 add_entry (DBusHashTable *table,
707 DBusHashEntry ***bucket)
709 DBusHashEntry *entry;
712 entry = alloc_entry (table);
722 b = &(table->buckets[idx]);
729 table->n_entries += 1;
731 /* note we ONLY rebuild when ADDING - because you can iterate over a
732 * table and remove entries safely.
734 if (table->n_entries >= table->hi_rebuild_size ||
735 table->n_entries < table->lo_rebuild_size)
736 rebuild_table (table);
742 string_hash (const char *str)
744 register unsigned int result;
748 * I tried a zillion different hash functions and asked many other
749 * people for advice. Many people had their own favorite functions,
750 * all different, but no-one had much idea why they were good ones.
751 * I chose the one below (multiply by 9 and add new character)
752 * because of the following reasons:
754 * 1. Multiplying by 10 is perfect for keys that are decimal strings,
755 * and multiplying by 9 is just about as good.
756 * 2. Times-9 is (shift-left-3) plus (old). This means that each
757 * character's bits hang around in the low-order bits of the
758 * hash value for ever, plus they spread fairly rapidly up to
759 * the high-order bits to fill out the hash value. This seems
760 * works well both for decimal and non-decimal strings.
771 result += (result << 3) + c;
777 static DBusHashEntry*
778 find_string_function (DBusHashTable *table,
780 dbus_bool_t create_if_not_found,
781 DBusHashEntry ***bucket)
783 DBusHashEntry *entry;
789 idx = string_hash (key) & table->mask;
791 /* Search all of the entries in this bucket. */
792 entry = table->buckets[idx];
793 while (entry != NULL)
795 if (strcmp (key, entry->key) == 0)
798 *bucket = &(table->buckets[idx]);
805 if (create_if_not_found)
806 entry = add_entry (table, idx, key, bucket);
811 static DBusHashEntry*
812 find_direct_function (DBusHashTable *table,
814 dbus_bool_t create_if_not_found,
815 DBusHashEntry ***bucket)
817 DBusHashEntry *entry;
823 idx = RANDOM_INDEX (table, key) & table->mask;
825 /* Search all of the entries in this bucket. */
826 entry = table->buckets[idx];
827 while (entry != NULL)
829 if (key == entry->key)
832 *bucket = &(table->buckets[idx]);
839 /* Entry not found. Add a new one to the bucket. */
840 if (create_if_not_found)
841 entry = add_entry (table, idx, key, bucket);
847 rebuild_table (DBusHashTable *table)
851 DBusHashEntry **old_buckets;
852 DBusHashEntry **old_chain;
853 DBusHashEntry *entry;
857 * Allocate and initialize the new bucket array, and set up
858 * hashing constants for new array size.
861 growing = table->n_entries >= table->hi_rebuild_size;
863 old_size = table->n_buckets;
864 old_buckets = table->buckets;
868 /* overflow paranoia */
869 if (table->n_buckets < _DBUS_INT_MAX / 4 &&
870 table->down_shift >= 0)
871 new_buckets = table->n_buckets * 4;
873 return; /* can't grow anymore */
877 new_buckets = table->n_buckets / 4;
878 if (new_buckets < DBUS_SMALL_HASH_TABLE)
879 return; /* don't bother shrinking this far */
882 table->buckets = dbus_new0 (DBusHashEntry*, new_buckets);
883 if (table->buckets == NULL)
885 /* out of memory, yay - just don't reallocate, the table will
886 * still work, albeit more slowly.
888 table->buckets = old_buckets;
892 table->n_buckets = new_buckets;
896 table->lo_rebuild_size = table->hi_rebuild_size;
897 table->hi_rebuild_size *= 4;
899 table->down_shift -= 2; /* keep 2 more high bits */
900 table->mask = (table->mask << 2) + 3; /* keep 2 more high bits */
904 table->hi_rebuild_size = table->lo_rebuild_size;
905 table->lo_rebuild_size /= 4;
907 table->down_shift += 2; /* keep 2 fewer high bits */
908 table->mask = table->mask >> 2; /* keep 2 fewer high bits */
912 printf ("%s table to lo = %d hi = %d downshift = %d mask = 0x%x\n",
913 growing ? "GROW" : "SHRINK",
914 table->lo_rebuild_size,
915 table->hi_rebuild_size,
920 _dbus_assert (table->lo_rebuild_size >= 0);
921 _dbus_assert (table->hi_rebuild_size > table->lo_rebuild_size);
922 _dbus_assert (table->mask != 0);
923 /* the mask is essentially the max index */
924 _dbus_assert (table->mask < table->n_buckets);
927 * Rehash all of the existing entries into the new bucket array.
930 for (old_chain = old_buckets; old_size > 0; old_size--, old_chain++)
932 for (entry = *old_chain; entry != NULL; entry = *old_chain)
935 DBusHashEntry **bucket;
937 *old_chain = entry->next;
938 switch (table->key_type)
940 case DBUS_HASH_STRING:
941 idx = string_hash (entry->key) & table->mask;
944 case DBUS_HASH_POINTER:
945 idx = RANDOM_INDEX (table, entry->key);
949 _dbus_assert_not_reached ("Unknown hash table type");
953 bucket = &(table->buckets[idx]);
954 entry->next = *bucket;
959 /* Free the old bucket array, if it was dynamically allocated. */
961 if (old_buckets != table->static_buckets)
962 dbus_free (old_buckets);
966 * Looks up the value for a given string in a hash table
967 * of type #DBUS_HASH_STRING. Returns %NULL if the value
968 * is not present. (A not-present entry is indistinguishable
969 * from an entry with a value of %NULL.)
970 * @param table the hash table.
971 * @param key the string to look up.
972 * @returns the value of the hash entry.
975 _dbus_hash_table_lookup_string (DBusHashTable *table,
978 DBusHashEntry *entry;
980 _dbus_assert (table->key_type == DBUS_HASH_STRING);
982 entry = (* table->find_function) (table, (char*) key, FALSE, NULL);
991 * Looks up the value for a given integer in a hash table
992 * of type #DBUS_HASH_INT. Returns %NULL if the value
993 * is not present. (A not-present entry is indistinguishable
994 * from an entry with a value of %NULL.)
995 * @param table the hash table.
996 * @param key the integer to look up.
997 * @returns the value of the hash entry.
1000 _dbus_hash_table_lookup_int (DBusHashTable *table,
1003 DBusHashEntry *entry;
1005 _dbus_assert (table->key_type == DBUS_HASH_INT);
1007 entry = (* table->find_function) (table, _DBUS_INT_TO_POINTER (key), FALSE, NULL);
1010 return entry->value;
1016 * Looks up the value for a given integer in a hash table
1017 * of type #DBUS_HASH_POINTER. Returns %NULL if the value
1018 * is not present. (A not-present entry is indistinguishable
1019 * from an entry with a value of %NULL.)
1020 * @param table the hash table.
1021 * @param key the integer to look up.
1022 * @returns the value of the hash entry.
1025 _dbus_hash_table_lookup_pointer (DBusHashTable *table,
1028 DBusHashEntry *entry;
1030 _dbus_assert (table->key_type == DBUS_HASH_POINTER);
1032 entry = (* table->find_function) (table, key, FALSE, NULL);
1035 return entry->value;
1041 * Removes the hash entry for the given key. If no hash entry
1042 * for the key exists, does nothing.
1044 * @param table the hash table.
1045 * @param key the hash key.
1046 * @returns #TRUE if the entry existed
1049 _dbus_hash_table_remove_string (DBusHashTable *table,
1052 DBusHashEntry *entry;
1053 DBusHashEntry **bucket;
1055 _dbus_assert (table->key_type == DBUS_HASH_STRING);
1057 entry = (* table->find_function) (table, (char*) key, FALSE, &bucket);
1061 remove_entry (table, bucket, entry);
1069 * Removes the hash entry for the given key. If no hash entry
1070 * for the key exists, does nothing.
1072 * @param table the hash table.
1073 * @param key the hash key.
1074 * @returns #TRUE if the entry existed
1077 _dbus_hash_table_remove_int (DBusHashTable *table,
1080 DBusHashEntry *entry;
1081 DBusHashEntry **bucket;
1083 _dbus_assert (table->key_type == DBUS_HASH_INT);
1085 entry = (* table->find_function) (table, _DBUS_INT_TO_POINTER (key), FALSE, &bucket);
1089 remove_entry (table, bucket, entry);
1097 * Removes the hash entry for the given key. If no hash entry
1098 * for the key exists, does nothing.
1100 * @param table the hash table.
1101 * @param key the hash key.
1102 * @returns #TRUE if the entry existed
1105 _dbus_hash_table_remove_pointer (DBusHashTable *table,
1108 DBusHashEntry *entry;
1109 DBusHashEntry **bucket;
1111 _dbus_assert (table->key_type == DBUS_HASH_POINTER);
1113 entry = (* table->find_function) (table, key, FALSE, &bucket);
1117 remove_entry (table, bucket, entry);
1126 * Creates a hash entry with the given key and value.
1127 * The key and value are not copied; they are stored
1128 * in the hash table by reference. If an entry with the
1129 * given key already exists, the previous key and value
1130 * are overwritten (and freed if the hash table has
1131 * a key_free_function and/or value_free_function).
1133 * Returns #FALSE if memory for the new hash entry
1134 * can't be allocated.
1136 * @param table the hash table.
1137 * @param key the hash entry key.
1138 * @param value the hash entry value.
1141 _dbus_hash_table_insert_string (DBusHashTable *table,
1145 DBusHashEntry *entry;
1147 _dbus_assert (table->key_type == DBUS_HASH_STRING);
1149 entry = (* table->find_function) (table, key, TRUE, NULL);
1152 return FALSE; /* no memory */
1154 if (table->free_key_function && entry->key != key)
1155 (* table->free_key_function) (entry->key);
1157 if (table->free_value_function && entry->value != value)
1158 (* table->free_value_function) (entry->value);
1161 entry->value = value;
1167 * Creates a hash entry with the given key and value.
1168 * The key and value are not copied; they are stored
1169 * in the hash table by reference. If an entry with the
1170 * given key already exists, the previous key and value
1171 * are overwritten (and freed if the hash table has
1172 * a key_free_function and/or value_free_function).
1174 * Returns #FALSE if memory for the new hash entry
1175 * can't be allocated.
1177 * @param table the hash table.
1178 * @param key the hash entry key.
1179 * @param value the hash entry value.
1182 _dbus_hash_table_insert_int (DBusHashTable *table,
1186 DBusHashEntry *entry;
1188 _dbus_assert (table->key_type == DBUS_HASH_INT);
1190 entry = (* table->find_function) (table, _DBUS_INT_TO_POINTER (key), TRUE, NULL);
1193 return FALSE; /* no memory */
1195 if (table->free_key_function && entry->key != _DBUS_INT_TO_POINTER (key))
1196 (* table->free_key_function) (entry->key);
1198 if (table->free_value_function && entry->value != value)
1199 (* table->free_value_function) (entry->value);
1201 entry->key = _DBUS_INT_TO_POINTER (key);
1202 entry->value = value;
1208 * Creates a hash entry with the given key and value.
1209 * The key and value are not copied; they are stored
1210 * in the hash table by reference. If an entry with the
1211 * given key already exists, the previous key and value
1212 * are overwritten (and freed if the hash table has
1213 * a key_free_function and/or value_free_function).
1215 * Returns #FALSE if memory for the new hash entry
1216 * can't be allocated.
1218 * @param table the hash table.
1219 * @param key the hash entry key.
1220 * @param value the hash entry value.
1223 _dbus_hash_table_insert_pointer (DBusHashTable *table,
1227 DBusHashEntry *entry;
1229 _dbus_assert (table->key_type == DBUS_HASH_POINTER);
1231 entry = (* table->find_function) (table, key, TRUE, NULL);
1234 return FALSE; /* no memory */
1236 if (table->free_key_function && entry->key != key)
1237 (* table->free_key_function) (entry->key);
1239 if (table->free_value_function && entry->value != value)
1240 (* table->free_value_function) (entry->value);
1243 entry->value = value;
1249 * Gets the number of hash entries in a hash table.
1251 * @param table the hash table.
1252 * @returns the number of entries in the table.
1255 _dbus_hash_table_get_n_entries (DBusHashTable *table)
1257 return table->n_entries;
1262 #ifdef DBUS_BUILD_TESTS
1263 #include "dbus-test.h"
1266 /* If you're wondering why the hash table test takes
1267 * forever to run, it's because we call this function
1268 * in inner loops thus making things quadratic.
1271 count_entries (DBusHashTable *table)
1277 _dbus_hash_iter_init (table, &iter);
1278 while (_dbus_hash_iter_next (&iter))
1281 _dbus_assert (count == _dbus_hash_table_get_n_entries (table));
1287 * @ingroup DBusHashTableInternals
1288 * Unit test for DBusHashTable
1289 * @returns #TRUE on success.
1292 _dbus_hash_test (void)
1295 DBusHashTable *table1;
1296 DBusHashTable *table2;
1298 #define N_HASH_KEYS 5000
1299 char keys[N_HASH_KEYS][128];
1301 printf ("Computing test hash keys...\n");
1303 while (i < N_HASH_KEYS)
1305 sprintf (keys[i], "Hash key %d", i);
1308 printf ("... done.\n");
1310 table1 = _dbus_hash_table_new (DBUS_HASH_STRING,
1311 dbus_free, dbus_free);
1315 table2 = _dbus_hash_table_new (DBUS_HASH_INT,
1320 /* Insert and remove a bunch of stuff, counting the table in between
1321 * to be sure it's not broken and that iteration works
1329 key = _dbus_strdup (keys[i]);
1332 value = _dbus_strdup ("Value!");
1336 if (!_dbus_hash_table_insert_string (table1,
1340 value = _dbus_strdup (keys[i]);
1344 if (!_dbus_hash_table_insert_int (table2,
1348 _dbus_assert (count_entries (table1) == i + 1);
1349 _dbus_assert (count_entries (table2) == i + 1);
1351 value = _dbus_hash_table_lookup_string (table1, keys[i]);
1352 _dbus_assert (value != NULL);
1353 _dbus_assert (strcmp (value, "Value!") == 0);
1355 value = _dbus_hash_table_lookup_int (table2, i);
1356 _dbus_assert (value != NULL);
1357 _dbus_assert (strcmp (value, keys[i]) == 0);
1365 _dbus_hash_table_remove_string (table1,
1368 _dbus_hash_table_remove_int (table2, i);
1370 _dbus_assert (count_entries (table1) == i);
1371 _dbus_assert (count_entries (table2) == i);
1376 _dbus_hash_table_ref (table1);
1377 _dbus_hash_table_ref (table2);
1378 _dbus_hash_table_unref (table1);
1379 _dbus_hash_table_unref (table2);
1380 _dbus_hash_table_unref (table1);
1381 _dbus_hash_table_unref (table2);
1384 /* Insert a bunch of stuff then check
1385 * that iteration works correctly (finds the right
1386 * values, iter_set_value works, etc.)
1388 table1 = _dbus_hash_table_new (DBUS_HASH_STRING,
1389 dbus_free, dbus_free);
1393 table2 = _dbus_hash_table_new (DBUS_HASH_INT,
1404 key = _dbus_strdup (keys[i]);
1407 value = _dbus_strdup ("Value!");
1411 if (!_dbus_hash_table_insert_string (table1,
1415 value = _dbus_strdup (keys[i]);
1419 if (!_dbus_hash_table_insert_int (table2,
1423 _dbus_assert (count_entries (table1) == i + 1);
1424 _dbus_assert (count_entries (table2) == i + 1);
1429 _dbus_hash_iter_init (table1, &iter);
1430 while (_dbus_hash_iter_next (&iter))
1435 key = _dbus_hash_iter_get_string_key (&iter);
1436 value = _dbus_hash_iter_get_value (&iter);
1438 _dbus_assert (_dbus_hash_table_lookup_string (table1, key) == value);
1440 value = _dbus_strdup ("Different value!");
1444 _dbus_hash_iter_set_value (&iter, value);
1446 _dbus_assert (_dbus_hash_table_lookup_string (table1, key) == value);
1449 _dbus_hash_iter_init (table1, &iter);
1450 while (_dbus_hash_iter_next (&iter))
1452 _dbus_hash_iter_remove_entry (&iter);
1453 _dbus_assert (count_entries (table1) == i - 1);
1457 _dbus_hash_iter_init (table2, &iter);
1458 while (_dbus_hash_iter_next (&iter))
1463 key = _dbus_hash_iter_get_int_key (&iter);
1464 value = _dbus_hash_iter_get_value (&iter);
1466 _dbus_assert (_dbus_hash_table_lookup_int (table2, key) == value);
1468 value = _dbus_strdup ("Different value!");
1472 _dbus_hash_iter_set_value (&iter, value);
1474 _dbus_assert (_dbus_hash_table_lookup_int (table2, key) == value);
1477 i = count_entries (table2);
1478 _dbus_hash_iter_init (table2, &iter);
1479 while (_dbus_hash_iter_next (&iter))
1481 _dbus_hash_iter_remove_entry (&iter);
1482 _dbus_assert (count_entries (table2) + 1 == i);
1486 /* add/remove interleaved, to check that we grow/shrink the table
1495 key = _dbus_strdup (keys[i]);
1499 value = _dbus_strdup ("Value!");
1503 if (!_dbus_hash_table_insert_string (table1,
1516 key = _dbus_strdup (keys[i]);
1519 value = _dbus_strdup ("Value!");
1523 if (!_dbus_hash_table_remove_string (table1, keys[i]))
1526 if (!_dbus_hash_table_insert_string (table1,
1530 if (!_dbus_hash_table_remove_string (table1, keys[i]))
1533 _dbus_assert (_dbus_hash_table_get_n_entries (table1) == i);
1538 /* nuke these tables */
1539 _dbus_hash_table_unref (table1);
1540 _dbus_hash_table_unref (table2);
1543 /* Now do a bunch of things again using _dbus_hash_iter_lookup() to
1544 * be sure that interface works.
1546 table1 = _dbus_hash_table_new (DBUS_HASH_STRING,
1547 dbus_free, dbus_free);
1551 table2 = _dbus_hash_table_new (DBUS_HASH_INT,
1562 key = _dbus_strdup (keys[i]);
1565 value = _dbus_strdup ("Value!");
1569 if (!_dbus_hash_iter_lookup (table1,
1572 _dbus_assert (_dbus_hash_iter_get_value (&iter) == NULL);
1573 _dbus_hash_iter_set_value (&iter, value);
1575 value = _dbus_strdup (keys[i]);
1579 if (!_dbus_hash_iter_lookup (table2,
1580 _DBUS_INT_TO_POINTER (i), TRUE, &iter))
1582 _dbus_assert (_dbus_hash_iter_get_value (&iter) == NULL);
1583 _dbus_hash_iter_set_value (&iter, value);
1585 _dbus_assert (count_entries (table1) == i + 1);
1586 _dbus_assert (count_entries (table2) == i + 1);
1588 if (!_dbus_hash_iter_lookup (table1, keys[i], FALSE, &iter))
1591 value = _dbus_hash_iter_get_value (&iter);
1592 _dbus_assert (value != NULL);
1593 _dbus_assert (strcmp (value, "Value!") == 0);
1595 /* Iterate just to be sure it works, though
1596 * it's a stupid thing to do
1598 while (_dbus_hash_iter_next (&iter))
1601 if (!_dbus_hash_iter_lookup (table2, _DBUS_INT_TO_POINTER (i), FALSE, &iter))
1604 value = _dbus_hash_iter_get_value (&iter);
1605 _dbus_assert (value != NULL);
1606 _dbus_assert (strcmp (value, keys[i]) == 0);
1608 /* Iterate just to be sure it works, though
1609 * it's a stupid thing to do
1611 while (_dbus_hash_iter_next (&iter))
1620 if (!_dbus_hash_iter_lookup (table1, keys[i], FALSE, &iter))
1621 _dbus_assert_not_reached ("hash entry should have existed");
1622 _dbus_hash_iter_remove_entry (&iter);
1624 if (!_dbus_hash_iter_lookup (table2, _DBUS_INT_TO_POINTER (i), FALSE, &iter))
1625 _dbus_assert_not_reached ("hash entry should have existed");
1626 _dbus_hash_iter_remove_entry (&iter);
1628 _dbus_assert (count_entries (table1) == i);
1629 _dbus_assert (count_entries (table2) == i);
1634 _dbus_hash_table_unref (table1);
1635 _dbus_hash_table_unref (table2);
1641 #endif /* DBUS_BUILD_TESTS */