1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
21 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
22 * file for a list of people on the GLib Team. See the ChangeLog
23 * files for a list of changes. These files are distributed with
24 * GLib at ftp://ftp.gtk.org/pub/gtk/.
33 #include <string.h> /* memset */
37 #include "gstrfuncs.h"
39 #include "gtestutils.h"
46 * @short_description: associations between keys and values so that
47 * given a key the value can be found quickly
49 * A #GHashTable provides associations between keys and values which is
50 * optimized so that given a key, the associated value can be found
53 * Note that neither keys nor values are copied when inserted into the
54 * #GHashTable, so they must exist for the lifetime of the #GHashTable.
55 * This means that the use of static strings is OK, but temporary
56 * strings (i.e. those created in buffers and those returned by GTK+
57 * widgets) should be copied with g_strdup() before being inserted.
59 * If keys or values are dynamically allocated, you must be careful to
60 * ensure that they are freed when they are removed from the
61 * #GHashTable, and also when they are overwritten by new insertions
62 * into the #GHashTable. It is also not advisable to mix static strings
63 * and dynamically-allocated strings in a #GHashTable, because it then
64 * becomes difficult to determine whether the string should be freed.
66 * To create a #GHashTable, use g_hash_table_new().
68 * To insert a key and value into a #GHashTable, use
69 * g_hash_table_insert().
71 * To lookup a value corresponding to a given key, use
72 * g_hash_table_lookup() and g_hash_table_lookup_extended().
74 * g_hash_table_lookup_extended() can also be used to simply
75 * check if a key is present in the hash table.
77 * To remove a key and value, use g_hash_table_remove().
79 * To call a function for each key and value pair use
80 * g_hash_table_foreach() or use a iterator to iterate over the
81 * key/value pairs in the hash table, see #GHashTableIter.
83 * To destroy a #GHashTable use g_hash_table_destroy().
86 * <title>Using a GHashTable as a set</title>
88 * A common use-case for hash tables is to store information about
89 * a set of keys, without associating any particular value with each
90 * key. GHashTable optimizes one way of doing so: If you store only
91 * key-value pairs where key == value, then GHashTable does not
92 * allocate memory to store the values, which can be a considerable
93 * space saving, if your set is large.
97 * set_new (GHashFunc hash_func,
98 * GEqualFunc equal_func,
99 * GDestroyNotify destroy)
101 * return g_hash_table_new_full (hash_func, equal_func, destroy, NULL);
105 * set_insert (GHashTable *set,
108 * g_hash_table_insert (set, element, element);
112 * set_contains (GHashTable *set,
115 * return g_hash_table_lookup_extended (set, element, NULL, NULL);
119 * set_remove (GHashTable *set,
122 * return g_hash_table_remove (set, element);
127 * As of version 2.32, there is also a g_hash_table_add() function to
128 * add a key to a #GHashTable that is being used as a set.
134 * The #GHashTable struct is an opaque data structure to represent a
135 * <link linkend="glib-Hash-Tables">Hash Table</link>. It should only be
136 * accessed via the following functions.
143 * Specifies the type of the hash function which is passed to
144 * g_hash_table_new() when a #GHashTable is created.
146 * The function is passed a key and should return a #guint hash value.
147 * The functions g_direct_hash(), g_int_hash() and g_str_hash() provide
148 * hash functions which can be used when the key is a #gpointer, #gint*,
149 * and #gchar* respectively.
151 * g_direct_hash() is also the appropriate hash function for keys
152 * of the form <literal>GINT_TO_POINTER (n)</literal> (or similar macros).
154 * <!-- FIXME: Need more here. --> The hash values should be evenly
155 * distributed over a fairly large range? The modulus is taken with the
156 * hash table size (a prime number) to find the 'bucket' to place each
157 * key into. The function should also be very fast, since it is called
158 * for each key lookup.
160 * Returns: the hash value corresponding to the key
166 * @value: the value corresponding to the key
167 * @user_data: user data passed to g_hash_table_foreach()
169 * Specifies the type of the function passed to g_hash_table_foreach().
170 * It is called with each key/value pair, together with the @user_data
171 * parameter which is passed to g_hash_table_foreach().
177 * @value: the value associated with the key
178 * @user_data: user data passed to g_hash_table_remove()
180 * Specifies the type of the function passed to
181 * g_hash_table_foreach_remove(). It is called with each key/value
182 * pair, together with the @user_data parameter passed to
183 * g_hash_table_foreach_remove(). It should return %TRUE if the
184 * key/value pair should be removed from the #GHashTable.
186 * Returns: %TRUE if the key/value pair should be removed from the
193 * @b: a value to compare with
195 * Specifies the type of a function used to test two values for
196 * equality. The function should return %TRUE if both values are equal
197 * and %FALSE otherwise.
199 * Returns: %TRUE if @a = @b; %FALSE otherwise
205 * A GHashTableIter structure represents an iterator that can be used
206 * to iterate over the elements of a #GHashTable. GHashTableIter
207 * structures are typically allocated on the stack and then initialized
208 * with g_hash_table_iter_init().
212 * g_hash_table_freeze:
213 * @hash_table: a #GHashTable
215 * This function is deprecated and will be removed in the next major
216 * release of GLib. It does nothing.
221 * @hash_table: a #GHashTable
223 * This function is deprecated and will be removed in the next major
224 * release of GLib. It does nothing.
227 #define HASH_TABLE_MIN_SHIFT 3 /* 1 << 3 == 8 buckets */
229 #define UNUSED_HASH_VALUE 0
230 #define TOMBSTONE_HASH_VALUE 1
231 #define HASH_IS_UNUSED(h_) ((h_) == UNUSED_HASH_VALUE)
232 #define HASH_IS_TOMBSTONE(h_) ((h_) == TOMBSTONE_HASH_VALUE)
233 #define HASH_IS_REAL(h_) ((h_) >= 2)
241 gint noccupied; /* nnodes + tombstones */
248 GEqualFunc key_equal_func;
250 #ifndef G_DISABLE_ASSERT
252 * Tracks the structure of the hash table, not its contents: is only
253 * incremented when a node is added or removed (is not incremented
254 * when the key or data of a node is modified).
258 GDestroyNotify key_destroy_func;
259 GDestroyNotify value_destroy_func;
264 GHashTable *hash_table;
272 /* Each table size has an associated prime modulo (the first prime
273 * lower than the table size) used to find the initial bucket. Probing
274 * then works modulo 2^n. The prime modulo is necessary to get a
275 * good distribution with poor hash functions.
277 static const gint prime_mod [] =
295 65521, /* For 1 << 16 */
310 2147483647 /* For 1 << 31 */
314 g_hash_table_set_shift (GHashTable *hash_table, gint shift)
319 hash_table->size = 1 << shift;
320 hash_table->mod = prime_mod [shift];
322 for (i = 0; i < shift; i++)
328 hash_table->mask = mask;
332 g_hash_table_find_closest_shift (gint n)
343 g_hash_table_set_shift_from_size (GHashTable *hash_table, gint size)
347 shift = g_hash_table_find_closest_shift (size);
348 shift = MAX (shift, HASH_TABLE_MIN_SHIFT);
350 g_hash_table_set_shift (hash_table, shift);
354 * g_hash_table_lookup_node:
355 * @hash_table: our #GHashTable
356 * @key: the key to lookup against
357 * @hash_return: key hash return location
359 * Performs a lookup in the hash table, preserving extra information
360 * usually needed for insertion.
362 * This function first computes the hash value of the key using the
363 * user's hash function.
365 * If an entry in the table matching @key is found then this function
366 * returns the index of that entry in the table, and if not, the
367 * index of an unused node (empty or tombstone) where the key can be
370 * The computed hash value is returned in the variable pointed to
371 * by @hash_return. This is to save insertions from having to compute
372 * the hash record again for the new record.
374 * Returns: index of the described node
377 g_hash_table_lookup_node (GHashTable *hash_table,
384 guint first_tombstone = 0;
385 gboolean have_tombstone = FALSE;
388 hash_value = hash_table->hash_func (key);
389 if (G_UNLIKELY (!HASH_IS_REAL (hash_value)))
392 *hash_return = hash_value;
394 node_index = hash_value % hash_table->mod;
395 node_hash = hash_table->hashes[node_index];
397 while (!HASH_IS_UNUSED (node_hash))
399 /* We first check if our full hash values
400 * are equal so we can avoid calling the full-blown
401 * key equality function in most cases.
403 if (node_hash == hash_value)
405 gpointer node_key = hash_table->keys[node_index];
407 if (hash_table->key_equal_func)
409 if (hash_table->key_equal_func (node_key, key))
412 else if (node_key == key)
417 else if (HASH_IS_TOMBSTONE (node_hash) && !have_tombstone)
419 first_tombstone = node_index;
420 have_tombstone = TRUE;
425 node_index &= hash_table->mask;
426 node_hash = hash_table->hashes[node_index];
430 return first_tombstone;
436 * g_hash_table_remove_node:
437 * @hash_table: our #GHashTable
438 * @node: pointer to node to remove
439 * @notify: %TRUE if the destroy notify handlers are to be called
441 * Removes a node from the hash table and updates the node count.
442 * The node is replaced by a tombstone. No table resize is performed.
444 * If @notify is %TRUE then the destroy notify functions are called
445 * for the key and value of the hash node.
448 g_hash_table_remove_node (GHashTable *hash_table,
455 key = hash_table->keys[i];
456 value = hash_table->values[i];
458 /* Erect tombstone */
459 hash_table->hashes[i] = TOMBSTONE_HASH_VALUE;
462 hash_table->keys[i] = NULL;
463 hash_table->values[i] = NULL;
465 hash_table->nnodes--;
467 if (notify && hash_table->key_destroy_func)
468 hash_table->key_destroy_func (key);
470 if (notify && hash_table->value_destroy_func)
471 hash_table->value_destroy_func (value);
476 * g_hash_table_remove_all_nodes:
477 * @hash_table: our #GHashTable
478 * @notify: %TRUE if the destroy notify handlers are to be called
480 * Removes all nodes from the table. Since this may be a precursor to
481 * freeing the table entirely, no resize is performed.
483 * If @notify is %TRUE then the destroy notify functions are called
484 * for the key and value of the hash node.
487 g_hash_table_remove_all_nodes (GHashTable *hash_table,
494 hash_table->nnodes = 0;
495 hash_table->noccupied = 0;
498 (hash_table->key_destroy_func == NULL &&
499 hash_table->value_destroy_func == NULL))
501 memset (hash_table->hashes, 0, hash_table->size * sizeof (guint));
502 memset (hash_table->keys, 0, hash_table->size * sizeof (gpointer));
503 memset (hash_table->values, 0, hash_table->size * sizeof (gpointer));
508 for (i = 0; i < hash_table->size; i++)
510 if (HASH_IS_REAL (hash_table->hashes[i]))
512 key = hash_table->keys[i];
513 value = hash_table->values[i];
515 hash_table->hashes[i] = UNUSED_HASH_VALUE;
516 hash_table->keys[i] = NULL;
517 hash_table->values[i] = NULL;
519 if (hash_table->key_destroy_func != NULL)
520 hash_table->key_destroy_func (key);
522 if (hash_table->value_destroy_func != NULL)
523 hash_table->value_destroy_func (value);
525 else if (HASH_IS_TOMBSTONE (hash_table->hashes[i]))
527 hash_table->hashes[i] = UNUSED_HASH_VALUE;
533 * g_hash_table_resize:
534 * @hash_table: our #GHashTable
536 * Resizes the hash table to the optimal size based on the number of
537 * nodes currently held. If you call this function then a resize will
538 * occur, even if one does not need to occur.
539 * Use g_hash_table_maybe_resize() instead.
541 * This function may "resize" the hash table to its current size, with
542 * the side effect of cleaning up tombstones and otherwise optimizing
543 * the probe sequences.
546 g_hash_table_resize (GHashTable *hash_table)
549 gpointer *new_values;
554 old_size = hash_table->size;
555 g_hash_table_set_shift_from_size (hash_table, hash_table->nnodes * 2);
557 new_keys = g_new0 (gpointer, hash_table->size);
558 if (hash_table->keys == hash_table->values)
559 new_values = new_keys;
561 new_values = g_new0 (gpointer, hash_table->size);
562 new_hashes = g_new0 (guint, hash_table->size);
564 for (i = 0; i < old_size; i++)
566 guint node_hash = hash_table->hashes[i];
570 if (!HASH_IS_REAL (node_hash))
573 hash_val = node_hash % hash_table->mod;
575 while (!HASH_IS_UNUSED (new_hashes[hash_val]))
579 hash_val &= hash_table->mask;
582 new_hashes[hash_val] = hash_table->hashes[i];
583 new_keys[hash_val] = hash_table->keys[i];
584 new_values[hash_val] = hash_table->values[i];
587 if (hash_table->keys != hash_table->values)
588 g_free (hash_table->values);
590 g_free (hash_table->keys);
591 g_free (hash_table->hashes);
593 hash_table->keys = new_keys;
594 hash_table->values = new_values;
595 hash_table->hashes = new_hashes;
597 hash_table->noccupied = hash_table->nnodes;
601 * g_hash_table_maybe_resize:
602 * @hash_table: our #GHashTable
604 * Resizes the hash table, if needed.
606 * Essentially, calls g_hash_table_resize() if the table has strayed
607 * too far from its ideal size for its number of nodes.
610 g_hash_table_maybe_resize (GHashTable *hash_table)
612 gint noccupied = hash_table->noccupied;
613 gint size = hash_table->size;
615 if ((size > hash_table->nnodes * 4 && size > 1 << HASH_TABLE_MIN_SHIFT) ||
616 (size <= noccupied + (noccupied / 16)))
617 g_hash_table_resize (hash_table);
622 * @hash_func: a function to create a hash value from a key
623 * @key_equal_func: a function to check two keys for equality
625 * Creates a new #GHashTable with a reference count of 1.
627 * Hash values returned by @hash_func are used to determine where keys
628 * are stored within the #GHashTable data structure. The g_direct_hash(),
629 * g_int_hash(), g_int64_hash(), g_double_hash() and g_str_hash()
630 * functions are provided for some common types of keys.
631 * If @hash_func is %NULL, g_direct_hash() is used.
633 * @key_equal_func is used when looking up keys in the #GHashTable.
634 * The g_direct_equal(), g_int_equal(), g_int64_equal(), g_double_equal()
635 * and g_str_equal() functions are provided for the most common types
636 * of keys. If @key_equal_func is %NULL, keys are compared directly in
637 * a similar fashion to g_direct_equal(), but without the overhead of
640 * Return value: a new #GHashTable
643 g_hash_table_new (GHashFunc hash_func,
644 GEqualFunc key_equal_func)
646 return g_hash_table_new_full (hash_func, key_equal_func, NULL, NULL);
651 * g_hash_table_new_full:
652 * @hash_func: a function to create a hash value from a key
653 * @key_equal_func: a function to check two keys for equality
654 * @key_destroy_func: a function to free the memory allocated for the key
655 * used when removing the entry from the #GHashTable, or %NULL
656 * if you don't want to supply such a function.
657 * @value_destroy_func: a function to free the memory allocated for the
658 * value used when removing the entry from the #GHashTable, or %NULL
659 * if you don't want to supply such a function.
661 * Creates a new #GHashTable like g_hash_table_new() with a reference
662 * count of 1 and allows to specify functions to free the memory
663 * allocated for the key and value that get called when removing the
664 * entry from the #GHashTable.
666 * Return value: a new #GHashTable
669 g_hash_table_new_full (GHashFunc hash_func,
670 GEqualFunc key_equal_func,
671 GDestroyNotify key_destroy_func,
672 GDestroyNotify value_destroy_func)
674 GHashTable *hash_table;
676 hash_table = g_slice_new (GHashTable);
677 g_hash_table_set_shift (hash_table, HASH_TABLE_MIN_SHIFT);
678 hash_table->nnodes = 0;
679 hash_table->noccupied = 0;
680 hash_table->hash_func = hash_func ? hash_func : g_direct_hash;
681 hash_table->key_equal_func = key_equal_func;
682 hash_table->ref_count = 1;
683 #ifndef G_DISABLE_ASSERT
684 hash_table->version = 0;
686 hash_table->key_destroy_func = key_destroy_func;
687 hash_table->value_destroy_func = value_destroy_func;
688 hash_table->keys = g_new0 (gpointer, hash_table->size);
689 hash_table->values = hash_table->keys;
690 hash_table->hashes = g_new0 (guint, hash_table->size);
696 * g_hash_table_iter_init:
697 * @iter: an uninitialized #GHashTableIter
698 * @hash_table: a #GHashTable
700 * Initializes a key/value pair iterator and associates it with
701 * @hash_table. Modifying the hash table after calling this function
702 * invalidates the returned iterator.
704 * GHashTableIter iter;
705 * gpointer key, value;
707 * g_hash_table_iter_init (&iter, hash_table);
708 * while (g_hash_table_iter_next (&iter, &key, &value))
710 * /* do something with key and value */
717 g_hash_table_iter_init (GHashTableIter *iter,
718 GHashTable *hash_table)
720 RealIter *ri = (RealIter *) iter;
722 g_return_if_fail (iter != NULL);
723 g_return_if_fail (hash_table != NULL);
725 ri->hash_table = hash_table;
727 #ifndef G_DISABLE_ASSERT
728 ri->version = hash_table->version;
733 * g_hash_table_iter_next:
734 * @iter: an initialized #GHashTableIter
735 * @key: a location to store the key, or %NULL
736 * @value: a location to store the value, or %NULL
738 * Advances @iter and retrieves the key and/or value that are now
739 * pointed to as a result of this advancement. If %FALSE is returned,
740 * @key and @value are not set, and the iterator becomes invalid.
742 * Return value: %FALSE if the end of the #GHashTable has been reached.
747 g_hash_table_iter_next (GHashTableIter *iter,
751 RealIter *ri = (RealIter *) iter;
754 g_return_val_if_fail (iter != NULL, FALSE);
755 #ifndef G_DISABLE_ASSERT
756 g_return_val_if_fail (ri->version == ri->hash_table->version, FALSE);
758 g_return_val_if_fail (ri->position < ri->hash_table->size, FALSE);
760 position = ri->position;
765 if (position >= ri->hash_table->size)
767 ri->position = position;
771 while (!HASH_IS_REAL (ri->hash_table->hashes[position]));
774 *key = ri->hash_table->keys[position];
776 *value = ri->hash_table->values[position];
778 ri->position = position;
783 * g_hash_table_iter_get_hash_table:
784 * @iter: an initialized #GHashTableIter
786 * Returns the #GHashTable associated with @iter.
788 * Return value: the #GHashTable associated with @iter.
793 g_hash_table_iter_get_hash_table (GHashTableIter *iter)
795 g_return_val_if_fail (iter != NULL, NULL);
797 return ((RealIter *) iter)->hash_table;
801 iter_remove_or_steal (RealIter *ri, gboolean notify)
803 g_return_if_fail (ri != NULL);
804 #ifndef G_DISABLE_ASSERT
805 g_return_if_fail (ri->version == ri->hash_table->version);
807 g_return_if_fail (ri->position >= 0);
808 g_return_if_fail (ri->position < ri->hash_table->size);
810 g_hash_table_remove_node (ri->hash_table, ri->position, notify);
812 #ifndef G_DISABLE_ASSERT
814 ri->hash_table->version++;
819 * g_hash_table_iter_remove:
820 * @iter: an initialized #GHashTableIter
822 * Removes the key/value pair currently pointed to by the iterator
823 * from its associated #GHashTable. Can only be called after
824 * g_hash_table_iter_next() returned %TRUE, and cannot be called
825 * more than once for the same key/value pair.
827 * If the #GHashTable was created using g_hash_table_new_full(),
828 * the key and value are freed using the supplied destroy functions,
829 * otherwise you have to make sure that any dynamically allocated
830 * values are freed yourself.
835 g_hash_table_iter_remove (GHashTableIter *iter)
837 iter_remove_or_steal ((RealIter *) iter, TRUE);
841 * g_hash_table_insert_node:
842 * @hash_table: our #GHashTable
843 * @node_index: pointer to node to insert/replace
844 * @key_hash: key hash
845 * @key: key to replace with, or %NULL
846 * @value: value to replace with
847 * @keep_new_key: whether to replace the key in the node with @key
848 * @reusing_key: whether @key was taken out of the existing node
850 * Inserts a value at @node_index in the hash table and updates it.
852 * If @key has been taken out of the existing node (ie it is not
853 * passed in via a g_hash_table_insert/replace) call, then @reusing_key
857 g_hash_table_insert_node (GHashTable *hash_table,
862 gboolean keep_new_key,
863 gboolean reusing_key)
869 if (G_UNLIKELY (hash_table->keys == hash_table->values && key != value))
870 hash_table->values = g_memdup (hash_table->keys, sizeof (gpointer) * hash_table->size);
872 old_hash = hash_table->hashes[node_index];
873 old_key = hash_table->keys[node_index];
874 old_value = hash_table->values[node_index];
876 if (HASH_IS_REAL (old_hash))
879 hash_table->keys[node_index] = key;
880 hash_table->values[node_index] = value;
884 hash_table->keys[node_index] = key;
885 hash_table->values[node_index] = value;
886 hash_table->hashes[node_index] = key_hash;
888 hash_table->nnodes++;
890 if (HASH_IS_UNUSED (old_hash))
892 /* We replaced an empty node, and not a tombstone */
893 hash_table->noccupied++;
894 g_hash_table_maybe_resize (hash_table);
897 #ifndef G_DISABLE_ASSERT
898 hash_table->version++;
902 if (HASH_IS_REAL (old_hash))
904 if (hash_table->key_destroy_func && !reusing_key)
905 hash_table->key_destroy_func (keep_new_key ? old_key : key);
906 if (hash_table->value_destroy_func)
907 hash_table->value_destroy_func (old_value);
912 * g_hash_table_iter_replace:
913 * @iter: an initialized #GHashTableIter
914 * @value: the value to replace with
916 * Replaces the value currently pointed to by the iterator
917 * from its associated #GHashTable. Can only be called after
918 * g_hash_table_iter_next() returned %TRUE.
920 * If you supplied a @value_destroy_func when creating the
921 * #GHashTable, the old value is freed using that function.
926 g_hash_table_iter_replace (GHashTableIter *iter,
933 ri = (RealIter *) iter;
935 g_return_if_fail (ri != NULL);
936 #ifndef G_DISABLE_ASSERT
937 g_return_if_fail (ri->version == ri->hash_table->version);
939 g_return_if_fail (ri->position >= 0);
940 g_return_if_fail (ri->position < ri->hash_table->size);
942 node_hash = ri->hash_table->hashes[ri->position];
943 key = ri->hash_table->keys[ri->position];
945 g_hash_table_insert_node (ri->hash_table, ri->position, node_hash, key, value, TRUE, TRUE);
947 #ifndef G_DISABLE_ASSERT
949 ri->hash_table->version++;
954 * g_hash_table_iter_steal:
955 * @iter: an initialized #GHashTableIter
957 * Removes the key/value pair currently pointed to by the
958 * iterator from its associated #GHashTable, without calling
959 * the key and value destroy functions. Can only be called
960 * after g_hash_table_iter_next() returned %TRUE, and cannot
961 * be called more than once for the same key/value pair.
966 g_hash_table_iter_steal (GHashTableIter *iter)
968 iter_remove_or_steal ((RealIter *) iter, FALSE);
974 * @hash_table: a valid #GHashTable
976 * Atomically increments the reference count of @hash_table by one.
977 * This function is MT-safe and may be called from any thread.
979 * Return value: the passed in #GHashTable
984 g_hash_table_ref (GHashTable *hash_table)
986 g_return_val_if_fail (hash_table != NULL, NULL);
988 g_atomic_int_inc (&hash_table->ref_count);
994 * g_hash_table_unref:
995 * @hash_table: a valid #GHashTable
997 * Atomically decrements the reference count of @hash_table by one.
998 * If the reference count drops to 0, all keys and values will be
999 * destroyed, and all memory allocated by the hash table is released.
1000 * This function is MT-safe and may be called from any thread.
1005 g_hash_table_unref (GHashTable *hash_table)
1007 g_return_if_fail (hash_table != NULL);
1009 if (g_atomic_int_dec_and_test (&hash_table->ref_count))
1011 g_hash_table_remove_all_nodes (hash_table, TRUE);
1012 if (hash_table->keys != hash_table->values)
1013 g_free (hash_table->values);
1014 g_free (hash_table->keys);
1015 g_free (hash_table->hashes);
1016 g_slice_free (GHashTable, hash_table);
1021 * g_hash_table_destroy:
1022 * @hash_table: a #GHashTable
1024 * Destroys all keys and values in the #GHashTable and decrements its
1025 * reference count by 1. If keys and/or values are dynamically allocated,
1026 * you should either free them first or create the #GHashTable with destroy
1027 * notifiers using g_hash_table_new_full(). In the latter case the destroy
1028 * functions you supplied will be called on all keys and values during the
1029 * destruction phase.
1032 g_hash_table_destroy (GHashTable *hash_table)
1034 g_return_if_fail (hash_table != NULL);
1036 g_hash_table_remove_all (hash_table);
1037 g_hash_table_unref (hash_table);
1041 * g_hash_table_lookup:
1042 * @hash_table: a #GHashTable
1043 * @key: the key to look up
1045 * Looks up a key in a #GHashTable. Note that this function cannot
1046 * distinguish between a key that is not present and one which is present
1047 * and has the value %NULL. If you need this distinction, use
1048 * g_hash_table_lookup_extended().
1050 * Return value: the associated value, or %NULL if the key is not found
1053 g_hash_table_lookup (GHashTable *hash_table,
1059 g_return_val_if_fail (hash_table != NULL, NULL);
1061 node_index = g_hash_table_lookup_node (hash_table, key, &node_hash);
1063 return HASH_IS_REAL (hash_table->hashes[node_index])
1064 ? hash_table->values[node_index]
1069 * g_hash_table_lookup_extended:
1070 * @hash_table: a #GHashTable
1071 * @lookup_key: the key to look up
1072 * @orig_key: return location for the original key, or %NULL
1073 * @value: return location for the value associated with the key, or %NULL
1075 * Looks up a key in the #GHashTable, returning the original key and the
1076 * associated value and a #gboolean which is %TRUE if the key was found. This
1077 * is useful if you need to free the memory allocated for the original key,
1078 * for example before calling g_hash_table_remove().
1080 * You can actually pass %NULL for @lookup_key to test
1081 * whether the %NULL key exists, provided the hash and equal functions
1082 * of @hash_table are %NULL-safe.
1084 * Return value: %TRUE if the key was found in the #GHashTable
1087 g_hash_table_lookup_extended (GHashTable *hash_table,
1088 gconstpointer lookup_key,
1095 g_return_val_if_fail (hash_table != NULL, FALSE);
1097 node_index = g_hash_table_lookup_node (hash_table, lookup_key, &node_hash);
1099 if (!HASH_IS_REAL (hash_table->hashes[node_index]))
1103 *orig_key = hash_table->keys[node_index];
1106 *value = hash_table->values[node_index];
1112 * g_hash_table_insert_internal:
1113 * @hash_table: our #GHashTable
1114 * @key: the key to insert
1115 * @value: the value to insert
1116 * @keep_new_key: if %TRUE and this key already exists in the table
1117 * then call the destroy notify function on the old key. If %FALSE
1118 * then call the destroy notify function on the new key.
1120 * Implements the common logic for the g_hash_table_insert() and
1121 * g_hash_table_replace() functions.
1123 * Do a lookup of @key. If it is found, replace it with the new
1124 * @value (and perhaps the new @key). If it is not found, create
1128 g_hash_table_insert_internal (GHashTable *hash_table,
1131 gboolean keep_new_key)
1136 g_return_if_fail (hash_table != NULL);
1138 node_index = g_hash_table_lookup_node (hash_table, key, &key_hash);
1140 g_hash_table_insert_node (hash_table, node_index, key_hash, key, value, keep_new_key, FALSE);
1144 * g_hash_table_insert:
1145 * @hash_table: a #GHashTable
1146 * @key: a key to insert
1147 * @value: the value to associate with the key
1149 * Inserts a new key and value into a #GHashTable.
1151 * If the key already exists in the #GHashTable its current
1152 * value is replaced with the new value. If you supplied a
1153 * @value_destroy_func when creating the #GHashTable, the old
1154 * value is freed using that function. If you supplied a
1155 * @key_destroy_func when creating the #GHashTable, the passed
1156 * key is freed using that function.
1159 g_hash_table_insert (GHashTable *hash_table,
1163 g_hash_table_insert_internal (hash_table, key, value, FALSE);
1167 * g_hash_table_replace:
1168 * @hash_table: a #GHashTable
1169 * @key: a key to insert
1170 * @value: the value to associate with the key
1172 * Inserts a new key and value into a #GHashTable similar to
1173 * g_hash_table_insert(). The difference is that if the key
1174 * already exists in the #GHashTable, it gets replaced by the
1175 * new key. If you supplied a @value_destroy_func when creating
1176 * the #GHashTable, the old value is freed using that function.
1177 * If you supplied a @key_destroy_func when creating the
1178 * #GHashTable, the old key is freed using that function.
1181 g_hash_table_replace (GHashTable *hash_table,
1185 g_hash_table_insert_internal (hash_table, key, value, TRUE);
1190 * @hash_table: a #GHashTable
1191 * @key: a key to insert
1193 * This is a convenience function for using a #GHashTable as a set. It
1194 * is equivalent to calling g_hash_table_replace() with @key as both the
1195 * key and the value.
1197 * When a hash table only ever contains keys that have themselves as the
1198 * corresponding value it is able to be stored more efficiently. See
1199 * the discussion in the section description.
1204 g_hash_table_add (GHashTable *hash_table,
1207 g_hash_table_insert_internal (hash_table, key, key, TRUE);
1211 * g_hash_table_contains:
1212 * @hash_table: a #GHashTable
1213 * @key: a key to check
1215 * Checks if @key is in @hash_table.
1220 g_hash_table_contains (GHashTable *hash_table,
1226 g_return_val_if_fail (hash_table != NULL, FALSE);
1228 node_index = g_hash_table_lookup_node (hash_table, key, &node_hash);
1230 return HASH_IS_REAL (hash_table->hashes[node_index]);
1234 * g_hash_table_remove_internal:
1235 * @hash_table: our #GHashTable
1236 * @key: the key to remove
1237 * @notify: %TRUE if the destroy notify handlers are to be called
1238 * Return value: %TRUE if a node was found and removed, else %FALSE
1240 * Implements the common logic for the g_hash_table_remove() and
1241 * g_hash_table_steal() functions.
1243 * Do a lookup of @key and remove it if it is found, calling the
1244 * destroy notify handlers only if @notify is %TRUE.
1247 g_hash_table_remove_internal (GHashTable *hash_table,
1254 g_return_val_if_fail (hash_table != NULL, FALSE);
1256 node_index = g_hash_table_lookup_node (hash_table, key, &node_hash);
1258 if (!HASH_IS_REAL (hash_table->hashes[node_index]))
1261 g_hash_table_remove_node (hash_table, node_index, notify);
1262 g_hash_table_maybe_resize (hash_table);
1264 #ifndef G_DISABLE_ASSERT
1265 hash_table->version++;
1272 * g_hash_table_remove:
1273 * @hash_table: a #GHashTable
1274 * @key: the key to remove
1276 * Removes a key and its associated value from a #GHashTable.
1278 * If the #GHashTable was created using g_hash_table_new_full(), the
1279 * key and value are freed using the supplied destroy functions, otherwise
1280 * you have to make sure that any dynamically allocated values are freed
1283 * Returns: %TRUE if the key was found and removed from the #GHashTable
1286 g_hash_table_remove (GHashTable *hash_table,
1289 return g_hash_table_remove_internal (hash_table, key, TRUE);
1293 * g_hash_table_steal:
1294 * @hash_table: a #GHashTable
1295 * @key: the key to remove
1297 * Removes a key and its associated value from a #GHashTable without
1298 * calling the key and value destroy functions.
1300 * Returns: %TRUE if the key was found and removed from the #GHashTable
1303 g_hash_table_steal (GHashTable *hash_table,
1306 return g_hash_table_remove_internal (hash_table, key, FALSE);
1310 * g_hash_table_remove_all:
1311 * @hash_table: a #GHashTable
1313 * Removes all keys and their associated values from a #GHashTable.
1315 * If the #GHashTable was created using g_hash_table_new_full(),
1316 * the keys and values are freed using the supplied destroy functions,
1317 * otherwise you have to make sure that any dynamically allocated
1318 * values are freed yourself.
1323 g_hash_table_remove_all (GHashTable *hash_table)
1325 g_return_if_fail (hash_table != NULL);
1327 #ifndef G_DISABLE_ASSERT
1328 if (hash_table->nnodes != 0)
1329 hash_table->version++;
1332 g_hash_table_remove_all_nodes (hash_table, TRUE);
1333 g_hash_table_maybe_resize (hash_table);
1337 * g_hash_table_steal_all:
1338 * @hash_table: a #GHashTable
1340 * Removes all keys and their associated values from a #GHashTable
1341 * without calling the key and value destroy functions.
1346 g_hash_table_steal_all (GHashTable *hash_table)
1348 g_return_if_fail (hash_table != NULL);
1350 #ifndef G_DISABLE_ASSERT
1351 if (hash_table->nnodes != 0)
1352 hash_table->version++;
1355 g_hash_table_remove_all_nodes (hash_table, FALSE);
1356 g_hash_table_maybe_resize (hash_table);
1360 * g_hash_table_foreach_remove_or_steal:
1361 * @hash_table: a #GHashTable
1362 * @func: the user's callback function
1363 * @user_data: data for @func
1364 * @notify: %TRUE if the destroy notify handlers are to be called
1366 * Implements the common logic for g_hash_table_foreach_remove()
1367 * and g_hash_table_foreach_steal().
1369 * Iterates over every node in the table, calling @func with the key
1370 * and value of the node (and @user_data). If @func returns %TRUE the
1371 * node is removed from the table.
1373 * If @notify is true then the destroy notify handlers will be called
1374 * for each removed node.
1377 g_hash_table_foreach_remove_or_steal (GHashTable *hash_table,
1384 #ifndef G_DISABLE_ASSERT
1385 gint version = hash_table->version;
1388 for (i = 0; i < hash_table->size; i++)
1390 guint node_hash = hash_table->hashes[i];
1391 gpointer node_key = hash_table->keys[i];
1392 gpointer node_value = hash_table->values[i];
1394 if (HASH_IS_REAL (node_hash) &&
1395 (* func) (node_key, node_value, user_data))
1397 g_hash_table_remove_node (hash_table, i, notify);
1401 #ifndef G_DISABLE_ASSERT
1402 g_return_val_if_fail (version == hash_table->version, 0);
1406 g_hash_table_maybe_resize (hash_table);
1408 #ifndef G_DISABLE_ASSERT
1410 hash_table->version++;
1417 * g_hash_table_foreach_remove:
1418 * @hash_table: a #GHashTable
1419 * @func: the function to call for each key/value pair
1420 * @user_data: user data to pass to the function
1422 * Calls the given function for each key/value pair in the
1423 * #GHashTable. If the function returns %TRUE, then the key/value
1424 * pair is removed from the #GHashTable. If you supplied key or
1425 * value destroy functions when creating the #GHashTable, they are
1426 * used to free the memory allocated for the removed keys and values.
1428 * See #GHashTableIter for an alternative way to loop over the
1429 * key/value pairs in the hash table.
1431 * Return value: the number of key/value pairs removed
1434 g_hash_table_foreach_remove (GHashTable *hash_table,
1438 g_return_val_if_fail (hash_table != NULL, 0);
1439 g_return_val_if_fail (func != NULL, 0);
1441 return g_hash_table_foreach_remove_or_steal (hash_table, func, user_data, TRUE);
1445 * g_hash_table_foreach_steal:
1446 * @hash_table: a #GHashTable
1447 * @func: the function to call for each key/value pair
1448 * @user_data: user data to pass to the function
1450 * Calls the given function for each key/value pair in the
1451 * #GHashTable. If the function returns %TRUE, then the key/value
1452 * pair is removed from the #GHashTable, but no key or value
1453 * destroy functions are called.
1455 * See #GHashTableIter for an alternative way to loop over the
1456 * key/value pairs in the hash table.
1458 * Return value: the number of key/value pairs removed.
1461 g_hash_table_foreach_steal (GHashTable *hash_table,
1465 g_return_val_if_fail (hash_table != NULL, 0);
1466 g_return_val_if_fail (func != NULL, 0);
1468 return g_hash_table_foreach_remove_or_steal (hash_table, func, user_data, FALSE);
1472 * g_hash_table_foreach:
1473 * @hash_table: a #GHashTable
1474 * @func: the function to call for each key/value pair
1475 * @user_data: user data to pass to the function
1477 * Calls the given function for each of the key/value pairs in the
1478 * #GHashTable. The function is passed the key and value of each
1479 * pair, and the given @user_data parameter. The hash table may not
1480 * be modified while iterating over it (you can't add/remove
1481 * items). To remove all items matching a predicate, use
1482 * g_hash_table_foreach_remove().
1484 * See g_hash_table_find() for performance caveats for linear
1485 * order searches in contrast to g_hash_table_lookup().
1488 g_hash_table_foreach (GHashTable *hash_table,
1493 #ifndef G_DISABLE_ASSERT
1494 gint version = hash_table->version;
1497 g_return_if_fail (hash_table != NULL);
1498 g_return_if_fail (func != NULL);
1500 for (i = 0; i < hash_table->size; i++)
1502 guint node_hash = hash_table->hashes[i];
1503 gpointer node_key = hash_table->keys[i];
1504 gpointer node_value = hash_table->values[i];
1506 if (HASH_IS_REAL (node_hash))
1507 (* func) (node_key, node_value, user_data);
1509 #ifndef G_DISABLE_ASSERT
1510 g_return_if_fail (version == hash_table->version);
1516 * g_hash_table_find:
1517 * @hash_table: a #GHashTable
1518 * @predicate: function to test the key/value pairs for a certain property
1519 * @user_data: user data to pass to the function
1521 * Calls the given function for key/value pairs in the #GHashTable
1522 * until @predicate returns %TRUE. The function is passed the key
1523 * and value of each pair, and the given @user_data parameter. The
1524 * hash table may not be modified while iterating over it (you can't
1525 * add/remove items).
1527 * Note, that hash tables are really only optimized for forward
1528 * lookups, i.e. g_hash_table_lookup(). So code that frequently issues
1529 * g_hash_table_find() or g_hash_table_foreach() (e.g. in the order of
1530 * once per every entry in a hash table) should probably be reworked
1531 * to use additional or different data structures for reverse lookups
1532 * (keep in mind that an O(n) find/foreach operation issued for all n
1533 * values in a hash table ends up needing O(n*n) operations).
1535 * Return value: The value of the first key/value pair is returned,
1536 * for which @predicate evaluates to %TRUE. If no pair with the
1537 * requested property is found, %NULL is returned.
1542 g_hash_table_find (GHashTable *hash_table,
1547 #ifndef G_DISABLE_ASSERT
1548 gint version = hash_table->version;
1552 g_return_val_if_fail (hash_table != NULL, NULL);
1553 g_return_val_if_fail (predicate != NULL, NULL);
1557 for (i = 0; i < hash_table->size; i++)
1559 guint node_hash = hash_table->hashes[i];
1560 gpointer node_key = hash_table->keys[i];
1561 gpointer node_value = hash_table->values[i];
1563 if (HASH_IS_REAL (node_hash))
1564 match = predicate (node_key, node_value, user_data);
1566 #ifndef G_DISABLE_ASSERT
1567 g_return_val_if_fail (version == hash_table->version, NULL);
1578 * g_hash_table_size:
1579 * @hash_table: a #GHashTable
1581 * Returns the number of elements contained in the #GHashTable.
1583 * Return value: the number of key/value pairs in the #GHashTable.
1586 g_hash_table_size (GHashTable *hash_table)
1588 g_return_val_if_fail (hash_table != NULL, 0);
1590 return hash_table->nnodes;
1594 * g_hash_table_get_keys:
1595 * @hash_table: a #GHashTable
1597 * Retrieves every key inside @hash_table. The returned data
1598 * is valid until @hash_table is modified.
1600 * Return value: a #GList containing all the keys inside the hash
1601 * table. The content of the list is owned by the hash table and
1602 * should not be modified or freed. Use g_list_free() when done
1608 g_hash_table_get_keys (GHashTable *hash_table)
1613 g_return_val_if_fail (hash_table != NULL, NULL);
1616 for (i = 0; i < hash_table->size; i++)
1618 if (HASH_IS_REAL (hash_table->hashes[i]))
1619 retval = g_list_prepend (retval, hash_table->keys[i]);
1626 * g_hash_table_get_values:
1627 * @hash_table: a #GHashTable
1629 * Retrieves every value inside @hash_table. The returned data
1630 * is valid until @hash_table is modified.
1632 * Return value: a #GList containing all the values inside the hash
1633 * table. The content of the list is owned by the hash table and
1634 * should not be modified or freed. Use g_list_free() when done
1640 g_hash_table_get_values (GHashTable *hash_table)
1645 g_return_val_if_fail (hash_table != NULL, NULL);
1648 for (i = 0; i < hash_table->size; i++)
1650 if (HASH_IS_REAL (hash_table->hashes[i]))
1651 retval = g_list_prepend (retval, hash_table->values[i]);
1663 * @v2: a key to compare with @v1
1665 * Compares two strings for byte-by-byte equality and returns %TRUE
1666 * if they are equal. It can be passed to g_hash_table_new() as the
1667 * @key_equal_func parameter, when using non-%NULL strings as keys in a
1670 * Note that this function is primarily meant as a hash table comparison
1671 * function. For a general-purpose, %NULL-safe string comparison function,
1674 * Returns: %TRUE if the two keys match
1677 g_str_equal (gconstpointer v1,
1680 const gchar *string1 = v1;
1681 const gchar *string2 = v2;
1683 return strcmp (string1, string2) == 0;
1690 * Converts a string to a hash value.
1692 * This function implements the widely used "djb" hash apparently posted
1693 * by Daniel Bernstein to comp.lang.c some time ago. The 32 bit
1694 * unsigned hash value starts at 5381 and for each byte 'c' in the
1695 * string, is updated: <literal>hash = hash * 33 + c</literal>. This
1696 * function uses the signed value of each byte.
1698 * It can be passed to g_hash_table_new() as the @hash_func parameter,
1699 * when using non-%NULL strings as keys in a #GHashTable.
1701 * Returns: a hash value corresponding to the key
1704 g_str_hash (gconstpointer v)
1706 const signed char *p;
1709 for (p = v; *p != '\0'; p++)
1710 h = (h << 5) + h + *p;
1717 * @v: (allow-none): a #gpointer key
1719 * Converts a gpointer to a hash value.
1720 * It can be passed to g_hash_table_new() as the @hash_func parameter,
1721 * when using opaque pointers compared by pointer value as keys in a
1724 * This hash function is also appropriate for keys that are integers stored
1725 * in pointers, such as <literal>GINT_TO_POINTER (n)</literal>.
1727 * Returns: a hash value corresponding to the key.
1730 g_direct_hash (gconstpointer v)
1732 return GPOINTER_TO_UINT (v);
1737 * @v1: (allow-none): a key
1738 * @v2: (allow-none): a key to compare with @v1
1740 * Compares two #gpointer arguments and returns %TRUE if they are equal.
1741 * It can be passed to g_hash_table_new() as the @key_equal_func
1742 * parameter, when using opaque pointers compared by pointer value as keys
1745 * This equality function is also appropriate for keys that are integers stored
1746 * in pointers, such as <literal>GINT_TO_POINTER (n)</literal>.
1748 * Returns: %TRUE if the two keys match.
1751 g_direct_equal (gconstpointer v1,
1759 * @v1: a pointer to a #gint key
1760 * @v2: a pointer to a #gint key to compare with @v1
1762 * Compares the two #gint values being pointed to and returns
1763 * %TRUE if they are equal.
1764 * It can be passed to g_hash_table_new() as the @key_equal_func
1765 * parameter, when using non-%NULL pointers to integers as keys in a
1768 * Note that this function acts on pointers to #gint, not on #gint directly:
1769 * if your hash table's keys are of the form
1770 * <literal>GINT_TO_POINTER (n)</literal>, use g_direct_equal() instead.
1772 * Returns: %TRUE if the two keys match.
1775 g_int_equal (gconstpointer v1,
1778 return *((const gint*) v1) == *((const gint*) v2);
1783 * @v: a pointer to a #gint key
1785 * Converts a pointer to a #gint to a hash value.
1786 * It can be passed to g_hash_table_new() as the @hash_func parameter,
1787 * when using non-%NULL pointers to integer values as keys in a #GHashTable.
1789 * Note that this function acts on pointers to #gint, not on #gint directly:
1790 * if your hash table's keys are of the form
1791 * <literal>GINT_TO_POINTER (n)</literal>, use g_direct_hash() instead.
1793 * Returns: a hash value corresponding to the key.
1796 g_int_hash (gconstpointer v)
1798 return *(const gint*) v;
1803 * @v1: a pointer to a #gint64 key
1804 * @v2: a pointer to a #gint64 key to compare with @v1
1806 * Compares the two #gint64 values being pointed to and returns
1807 * %TRUE if they are equal.
1808 * It can be passed to g_hash_table_new() as the @key_equal_func
1809 * parameter, when using non-%NULL pointers to 64-bit integers as keys in a
1812 * Returns: %TRUE if the two keys match.
1817 g_int64_equal (gconstpointer v1,
1820 return *((const gint64*) v1) == *((const gint64*) v2);
1825 * @v: a pointer to a #gint64 key
1827 * Converts a pointer to a #gint64 to a hash value.
1829 * It can be passed to g_hash_table_new() as the @hash_func parameter,
1830 * when using non-%NULL pointers to 64-bit integer values as keys in a
1833 * Returns: a hash value corresponding to the key.
1838 g_int64_hash (gconstpointer v)
1840 return (guint) *(const gint64*) v;
1845 * @v1: a pointer to a #gdouble key
1846 * @v2: a pointer to a #gdouble key to compare with @v1
1848 * Compares the two #gdouble values being pointed to and returns
1849 * %TRUE if they are equal.
1850 * It can be passed to g_hash_table_new() as the @key_equal_func
1851 * parameter, when using non-%NULL pointers to doubles as keys in a
1854 * Returns: %TRUE if the two keys match.
1859 g_double_equal (gconstpointer v1,
1862 return *((const gdouble*) v1) == *((const gdouble*) v2);
1867 * @v: a pointer to a #gdouble key
1869 * Converts a pointer to a #gdouble to a hash value.
1870 * It can be passed to g_hash_table_new() as the @hash_func parameter,
1871 * It can be passed to g_hash_table_new() as the @hash_func parameter,
1872 * when using non-%NULL pointers to doubles as keys in a #GHashTable.
1874 * Returns: a hash value corresponding to the key.
1879 g_double_hash (gconstpointer v)
1881 return (guint) *(const gdouble*) v;