1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
3 *
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.
8 *
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.
13 *
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.
18 */
19
20 /*
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/.
25 */
26
27 /*
28 * MT safe
29 */
30
31 #include "config.h"
32
33 #include <string.h> /* memset */
34
35 #include "glib.h"
36 #include "galias.h"
37
38 #define HASH_TABLE_MIN_SHIFT 3 /* 1 << 3 == 8 buckets */
39
40 typedef struct _GHashNode GHashNode;
41
42 struct _GHashNode
43 {
44 gpointer key;
45 gpointer value;
46
47 /* If key_hash == 0, node is not in use
48 * If key_hash == 1, node is a tombstone
49 * If key_hash >= 2, node contains data */
50 guint key_hash;
51 };
52
53 struct _GHashTable
54 {
55 gint size;
56 gint mod;
57 guint mask;
58 gint nnodes;
59 gint noccupied; /* nnodes + tombstones */
60 GHashNode *nodes;
61 GHashFunc hash_func;
62 GEqualFunc key_equal_func;
63 volatile gint ref_count;
64 #ifndef G_DISABLE_ASSERT
65 /*
66 * Tracks the structure of the hash table, not its contents: is only
67 * incremented when a node is added or removed (is not incremented
68 * when the key or data of a node is modified).
69 */
70 int version;
71 #endif
72 GDestroyNotify key_destroy_func;
73 GDestroyNotify value_destroy_func;
74 };
75
76 typedef struct
77 {
78 GHashTable *hash_table;
79 gpointer dummy1;
80 gpointer dummy2;
81 int position;
82 gboolean dummy3;
83 int version;
84 } RealIter;
85
86 /* Each table size has an associated prime modulo (the first prime
87 * lower than the table size) used to find the initial bucket. Probing
88 * then works modulo 2^n. The prime modulo is necessary to get a
89 * good distribution with poor hash functions. */
90 static const gint prime_mod [] =
91 {
92 1, /* For 1 << 0 */
93 2,
94 3,
95 7,
96 13,
97 31,
98 61,
99 127,
100 251,
101 509,
102 1021,
103 2039,
104 4093,
105 8191,
106 16381,
107 32749,
108 65521, /* For 1 << 16 */
109 131071,
110 262139,
111 524287,
112 1048573,
113 2097143,
114 4194301,
115 8388593,
116 16777213,
117 33554393,
118 67108859,
119 134217689,
120 268435399,
121 536870909,
122 1073741789,
123 2147483647 /* For 1 << 31 */
124 };
125
126 static void
g_hash_table_set_shift(GHashTable * hash_table,gint shift)127 g_hash_table_set_shift (GHashTable *hash_table, gint shift)
128 {
129 gint i;
130 guint mask = 0;
131
132 hash_table->size = 1 << shift;
133 hash_table->mod = prime_mod [shift];
134
135 for (i = 0; i < shift; i++)
136 {
137 mask <<= 1;
138 mask |= 1;
139 }
140
141 hash_table->mask = mask;
142 }
143
144 static gint
g_hash_table_find_closest_shift(gint n)145 g_hash_table_find_closest_shift (gint n)
146 {
147 gint i;
148
149 for (i = 0; n; i++)
150 n >>= 1;
151
152 return i;
153 }
154
155 static void
g_hash_table_set_shift_from_size(GHashTable * hash_table,gint size)156 g_hash_table_set_shift_from_size (GHashTable *hash_table, gint size)
157 {
158 gint shift;
159
160 shift = g_hash_table_find_closest_shift (size);
161 shift = MAX (shift, HASH_TABLE_MIN_SHIFT);
162
163 g_hash_table_set_shift (hash_table, shift);
164 }
165
166 /*
167 * g_hash_table_lookup_node:
168 * @hash_table: our #GHashTable
169 * @key: the key to lookup against
170 * @hash_return: optional key hash return location
171 * Return value: index of the described #GHashNode
172 *
173 * Performs a lookup in the hash table. Virtually all hash operations
174 * will use this function internally.
175 *
176 * This function first computes the hash value of the key using the
177 * user's hash function.
178 *
179 * If an entry in the table matching @key is found then this function
180 * returns the index of that entry in the table, and if not, the
181 * index of an empty node (never a tombstone).
182 */
183 static inline guint
g_hash_table_lookup_node(GHashTable * hash_table,gconstpointer key)184 g_hash_table_lookup_node (GHashTable *hash_table,
185 gconstpointer key)
186 {
187 GHashNode *node;
188 guint node_index;
189 guint hash_value;
190 guint step = 0;
191
192 /* Empty buckets have hash_value set to 0, and for tombstones, it's 1.
193 * We need to make sure our hash value is not one of these. */
194
195 hash_value = (* hash_table->hash_func) (key);
196 if (G_UNLIKELY (hash_value <= 1))
197 hash_value = 2;
198
199 node_index = hash_value % hash_table->mod;
200 node = &hash_table->nodes [node_index];
201
202 while (node->key_hash)
203 {
204 /* We first check if our full hash values
205 * are equal so we can avoid calling the full-blown
206 * key equality function in most cases.
207 */
208
209 if (node->key_hash == hash_value)
210 {
211 if (hash_table->key_equal_func)
212 {
213 if (hash_table->key_equal_func (node->key, key))
214 break;
215 }
216 else if (node->key == key)
217 {
218 break;
219 }
220 }
221
222 step++;
223 node_index += step;
224 node_index &= hash_table->mask;
225 node = &hash_table->nodes [node_index];
226 }
227
228 return node_index;
229 }
230
231 /*
232 * g_hash_table_lookup_node_for_insertion:
233 * @hash_table: our #GHashTable
234 * @key: the key to lookup against
235 * @hash_return: key hash return location
236 * Return value: index of the described #GHashNode
237 *
238 * Performs a lookup in the hash table, preserving extra information
239 * usually needed for insertion.
240 *
241 * This function first computes the hash value of the key using the
242 * user's hash function.
243 *
244 * If an entry in the table matching @key is found then this function
245 * returns the index of that entry in the table, and if not, the
246 * index of an unused node (empty or tombstone) where the key can be
247 * inserted.
248 *
249 * The computed hash value is returned in the variable pointed to
250 * by @hash_return. This is to save insertions from having to compute
251 * the hash record again for the new record.
252 */
253 static inline guint
g_hash_table_lookup_node_for_insertion(GHashTable * hash_table,gconstpointer key,guint * hash_return)254 g_hash_table_lookup_node_for_insertion (GHashTable *hash_table,
255 gconstpointer key,
256 guint *hash_return)
257 {
258 GHashNode *node;
259 guint node_index;
260 guint hash_value;
261 guint first_tombstone;
262 gboolean have_tombstone = FALSE;
263 guint step = 0;
264
265 /* Empty buckets have hash_value set to 0, and for tombstones, it's 1.
266 * We need to make sure our hash value is not one of these. */
267
268 hash_value = (* hash_table->hash_func) (key);
269 if (G_UNLIKELY (hash_value <= 1))
270 hash_value = 2;
271
272 *hash_return = hash_value;
273
274 node_index = hash_value % hash_table->mod;
275 node = &hash_table->nodes [node_index];
276
277 while (node->key_hash)
278 {
279 /* We first check if our full hash values
280 * are equal so we can avoid calling the full-blown
281 * key equality function in most cases.
282 */
283
284 if (node->key_hash == hash_value)
285 {
286 if (hash_table->key_equal_func)
287 {
288 if (hash_table->key_equal_func (node->key, key))
289 return node_index;
290 }
291 else if (node->key == key)
292 {
293 return node_index;
294 }
295 }
296 else if (node->key_hash == 1 && !have_tombstone)
297 {
298 first_tombstone = node_index;
299 have_tombstone = TRUE;
300 }
301
302 step++;
303 node_index += step;
304 node_index &= hash_table->mask;
305 node = &hash_table->nodes [node_index];
306 }
307
308 if (have_tombstone)
309 return first_tombstone;
310
311 return node_index;
312 }
313
314 /*
315 * g_hash_table_remove_node:
316 * @hash_table: our #GHashTable
317 * @node: pointer to node to remove
318 * @notify: %TRUE if the destroy notify handlers are to be called
319 *
320 * Removes a node from the hash table and updates the node count.
321 * The node is replaced by a tombstone. No table resize is performed.
322 *
323 * If @notify is %TRUE then the destroy notify functions are called
324 * for the key and value of the hash node.
325 */
326 static void
g_hash_table_remove_node(GHashTable * hash_table,GHashNode * node,gboolean notify)327 g_hash_table_remove_node (GHashTable *hash_table,
328 GHashNode *node,
329 gboolean notify)
330 {
331 if (notify && hash_table->key_destroy_func)
332 hash_table->key_destroy_func (node->key);
333
334 if (notify && hash_table->value_destroy_func)
335 hash_table->value_destroy_func (node->value);
336
337 /* Erect tombstone */
338 node->key_hash = 1;
339
340 /* Be GC friendly */
341 node->key = NULL;
342 node->value = NULL;
343
344 hash_table->nnodes--;
345 }
346
347 /*
348 * g_hash_table_remove_all_nodes:
349 * @hash_table: our #GHashTable
350 * @notify: %TRUE if the destroy notify handlers are to be called
351 *
352 * Removes all nodes from the table. Since this may be a precursor to
353 * freeing the table entirely, no resize is performed.
354 *
355 * If @notify is %TRUE then the destroy notify functions are called
356 * for the key and value of the hash node.
357 */
358 static void
g_hash_table_remove_all_nodes(GHashTable * hash_table,gboolean notify)359 g_hash_table_remove_all_nodes (GHashTable *hash_table,
360 gboolean notify)
361 {
362 int i;
363
364 for (i = 0; i < hash_table->size; i++)
365 {
366 GHashNode *node = &hash_table->nodes [i];
367
368 if (node->key_hash > 1)
369 {
370 if (notify && hash_table->key_destroy_func)
371 hash_table->key_destroy_func (node->key);
372
373 if (notify && hash_table->value_destroy_func)
374 hash_table->value_destroy_func (node->value);
375 }
376 }
377
378 /* We need to set node->key_hash = 0 for all nodes - might as well be GC
379 * friendly and clear everything */
380 memset (hash_table->nodes, 0, hash_table->size * sizeof (GHashNode));
381
382 hash_table->nnodes = 0;
383 hash_table->noccupied = 0;
384 }
385
386 /*
387 * g_hash_table_resize:
388 * @hash_table: our #GHashTable
389 *
390 * Resizes the hash table to the optimal size based on the number of
391 * nodes currently held. If you call this function then a resize will
392 * occur, even if one does not need to occur. Use
393 * g_hash_table_maybe_resize() instead.
394 *
395 * This function may "resize" the hash table to its current size, with
396 * the side effect of cleaning up tombstones and otherwise optimizing
397 * the probe sequences.
398 */
399 static void
g_hash_table_resize(GHashTable * hash_table)400 g_hash_table_resize (GHashTable *hash_table)
401 {
402 GHashNode *new_nodes;
403 gint old_size;
404 gint i;
405
406 old_size = hash_table->size;
407 g_hash_table_set_shift_from_size (hash_table, hash_table->nnodes * 2);
408
409 new_nodes = g_new0 (GHashNode, hash_table->size);
410
411 for (i = 0; i < old_size; i++)
412 {
413 GHashNode *node = &hash_table->nodes [i];
414 GHashNode *new_node;
415 guint hash_val;
416 guint step = 0;
417
418 if (node->key_hash <= 1)
419 continue;
420
421 hash_val = node->key_hash % hash_table->mod;
422 new_node = &new_nodes [hash_val];
423
424 while (new_node->key_hash)
425 {
426 step++;
427 hash_val += step;
428 hash_val &= hash_table->mask;
429 new_node = &new_nodes [hash_val];
430 }
431
432 *new_node = *node;
433 }
434
435 g_free (hash_table->nodes);
436 hash_table->nodes = new_nodes;
437 hash_table->noccupied = hash_table->nnodes;
438 }
439
440 /*
441 * g_hash_table_maybe_resize:
442 * @hash_table: our #GHashTable
443 *
444 * Resizes the hash table, if needed.
445 *
446 * Essentially, calls g_hash_table_resize() if the table has strayed
447 * too far from its ideal size for its number of nodes.
448 */
449 static inline void
g_hash_table_maybe_resize(GHashTable * hash_table)450 g_hash_table_maybe_resize (GHashTable *hash_table)
451 {
452 gint noccupied = hash_table->noccupied;
453 gint size = hash_table->size;
454
455 if ((size > hash_table->nnodes * 4 && size > 1 << HASH_TABLE_MIN_SHIFT) ||
456 (size <= noccupied + (noccupied / 16)))
457 g_hash_table_resize (hash_table);
458 }
459
460 /**
461 * g_hash_table_new:
462 * @hash_func: a function to create a hash value from a key.
463 * Hash values are used to determine where keys are stored within the
464 * #GHashTable data structure. The g_direct_hash(), g_int_hash() and
465 * g_str_hash() functions are provided for some common types of keys.
466 * If hash_func is %NULL, g_direct_hash() is used.
467 * @key_equal_func: a function to check two keys for equality. This is
468 * used when looking up keys in the #GHashTable. The g_direct_equal(),
469 * g_int_equal() and g_str_equal() functions are provided for the most
470 * common types of keys. If @key_equal_func is %NULL, keys are compared
471 * directly in a similar fashion to g_direct_equal(), but without the
472 * overhead of a function call.
473 *
474 * Creates a new #GHashTable with a reference count of 1.
475 *
476 * Return value: a new #GHashTable.
477 **/
478 GHashTable*
g_hash_table_new(GHashFunc hash_func,GEqualFunc key_equal_func)479 g_hash_table_new (GHashFunc hash_func,
480 GEqualFunc key_equal_func)
481 {
482 return g_hash_table_new_full (hash_func, key_equal_func, NULL, NULL);
483 }
484
485
486 /**
487 * g_hash_table_new_full:
488 * @hash_func: a function to create a hash value from a key.
489 * @key_equal_func: a function to check two keys for equality.
490 * @key_destroy_func: a function to free the memory allocated for the key
491 * used when removing the entry from the #GHashTable or %NULL if you
492 * don't want to supply such a function.
493 * @value_destroy_func: a function to free the memory allocated for the
494 * value used when removing the entry from the #GHashTable or %NULL if
495 * you don't want to supply such a function.
496 *
497 * Creates a new #GHashTable like g_hash_table_new() with a reference count
498 * of 1 and allows to specify functions to free the memory allocated for the
499 * key and value that get called when removing the entry from the #GHashTable.
500 *
501 * Return value: a new #GHashTable.
502 **/
503 GHashTable*
g_hash_table_new_full(GHashFunc hash_func,GEqualFunc key_equal_func,GDestroyNotify key_destroy_func,GDestroyNotify value_destroy_func)504 g_hash_table_new_full (GHashFunc hash_func,
505 GEqualFunc key_equal_func,
506 GDestroyNotify key_destroy_func,
507 GDestroyNotify value_destroy_func)
508 {
509 GHashTable *hash_table;
510
511 hash_table = g_slice_new (GHashTable);
512 g_hash_table_set_shift (hash_table, HASH_TABLE_MIN_SHIFT);
513 hash_table->nnodes = 0;
514 hash_table->noccupied = 0;
515 hash_table->hash_func = hash_func ? hash_func : g_direct_hash;
516 hash_table->key_equal_func = key_equal_func;
517 hash_table->ref_count = 1;
518 #ifndef G_DISABLE_ASSERT
519 hash_table->version = 0;
520 #endif
521 hash_table->key_destroy_func = key_destroy_func;
522 hash_table->value_destroy_func = value_destroy_func;
523 hash_table->nodes = g_new0 (GHashNode, hash_table->size);
524
525 return hash_table;
526 }
527
528 /**
529 * g_hash_table_iter_init:
530 * @iter: an uninitialized #GHashTableIter.
531 * @hash_table: a #GHashTable.
532 *
533 * Initializes a key/value pair iterator and associates it with
534 * @hash_table. Modifying the hash table after calling this function
535 * invalidates the returned iterator.
536 * |[
537 * GHashTableIter iter;
538 * gpointer key, value;
539 *
540 * g_hash_table_iter_init (&iter, hash_table);
541 * while (g_hash_table_iter_next (&iter, &key, &value))
542 * {
543 * /* do something with key and value */
544 * }
545 * ]|
546 *
547 * Since: 2.16
548 **/
549 void
g_hash_table_iter_init(GHashTableIter * iter,GHashTable * hash_table)550 g_hash_table_iter_init (GHashTableIter *iter,
551 GHashTable *hash_table)
552 {
553 RealIter *ri = (RealIter *) iter;
554
555 g_return_if_fail (iter != NULL);
556 g_return_if_fail (hash_table != NULL);
557
558 ri->hash_table = hash_table;
559 ri->position = -1;
560 #ifndef G_DISABLE_ASSERT
561 ri->version = hash_table->version;
562 #endif
563 }
564
565 /**
566 * g_hash_table_iter_next:
567 * @iter: an initialized #GHashTableIter.
568 * @key: a location to store the key, or %NULL.
569 * @value: a location to store the value, or %NULL.
570 *
571 * Advances @iter and retrieves the key and/or value that are now
572 * pointed to as a result of this advancement. If %FALSE is returned,
573 * @key and @value are not set, and the iterator becomes invalid.
574 *
575 * Return value: %FALSE if the end of the #GHashTable has been reached.
576 *
577 * Since: 2.16
578 **/
579 gboolean
g_hash_table_iter_next(GHashTableIter * iter,gpointer * key,gpointer * value)580 g_hash_table_iter_next (GHashTableIter *iter,
581 gpointer *key,
582 gpointer *value)
583 {
584 RealIter *ri = (RealIter *) iter;
585 GHashNode *node;
586 gint position;
587
588 g_return_val_if_fail (iter != NULL, FALSE);
589 #ifndef G_DISABLE_ASSERT
590 g_return_val_if_fail (ri->version == ri->hash_table->version, FALSE);
591 #endif
592 g_return_val_if_fail (ri->position < ri->hash_table->size, FALSE);
593
594 position = ri->position;
595
596 do
597 {
598 position++;
599 if (position >= ri->hash_table->size)
600 {
601 ri->position = position;
602 return FALSE;
603 }
604
605 node = &ri->hash_table->nodes [position];
606 }
607 while (node->key_hash <= 1);
608
609 if (key != NULL)
610 *key = node->key;
611 if (value != NULL)
612 *value = node->value;
613
614 ri->position = position;
615 return TRUE;
616 }
617
618 /**
619 * g_hash_table_iter_get_hash_table:
620 * @iter: an initialized #GHashTableIter.
621 *
622 * Returns the #GHashTable associated with @iter.
623 *
624 * Return value: the #GHashTable associated with @iter.
625 *
626 * Since: 2.16
627 **/
628 GHashTable *
g_hash_table_iter_get_hash_table(GHashTableIter * iter)629 g_hash_table_iter_get_hash_table (GHashTableIter *iter)
630 {
631 g_return_val_if_fail (iter != NULL, NULL);
632
633 return ((RealIter *) iter)->hash_table;
634 }
635
636 static void
iter_remove_or_steal(RealIter * ri,gboolean notify)637 iter_remove_or_steal (RealIter *ri, gboolean notify)
638 {
639 g_return_if_fail (ri != NULL);
640 #ifndef G_DISABLE_ASSERT
641 g_return_if_fail (ri->version == ri->hash_table->version);
642 #endif
643 g_return_if_fail (ri->position >= 0);
644 g_return_if_fail (ri->position < ri->hash_table->size);
645
646 g_hash_table_remove_node (ri->hash_table, &ri->hash_table->nodes [ri->position], notify);
647
648 #ifndef G_DISABLE_ASSERT
649 ri->version++;
650 ri->hash_table->version++;
651 #endif
652 }
653
654 /**
655 * g_hash_table_iter_remove():
656 * @iter: an initialized #GHashTableIter.
657 *
658 * Removes the key/value pair currently pointed to by the iterator
659 * from its associated #GHashTable. Can only be called after
660 * g_hash_table_iter_next() returned %TRUE, and cannot be called more
661 * than once for the same key/value pair.
662 *
663 * If the #GHashTable was created using g_hash_table_new_full(), the
664 * key and value are freed using the supplied destroy functions, otherwise
665 * you have to make sure that any dynamically allocated values are freed
666 * yourself.
667 *
668 * Since: 2.16
669 **/
670 void
g_hash_table_iter_remove(GHashTableIter * iter)671 g_hash_table_iter_remove (GHashTableIter *iter)
672 {
673 iter_remove_or_steal ((RealIter *) iter, TRUE);
674 }
675
676 /**
677 * g_hash_table_iter_steal():
678 * @iter: an initialized #GHashTableIter.
679 *
680 * Removes the key/value pair currently pointed to by the iterator
681 * from its associated #GHashTable, without calling the key and value
682 * destroy functions. Can only be called after
683 * g_hash_table_iter_next() returned %TRUE, and cannot be called more
684 * than once for the same key/value pair.
685 *
686 * Since: 2.16
687 **/
688 void
g_hash_table_iter_steal(GHashTableIter * iter)689 g_hash_table_iter_steal (GHashTableIter *iter)
690 {
691 iter_remove_or_steal ((RealIter *) iter, FALSE);
692 }
693
694
695 /**
696 * g_hash_table_ref:
697 * @hash_table: a valid #GHashTable.
698 *
699 * Atomically increments the reference count of @hash_table by one.
700 * This function is MT-safe and may be called from any thread.
701 *
702 * Return value: the passed in #GHashTable.
703 *
704 * Since: 2.10
705 **/
706 GHashTable*
g_hash_table_ref(GHashTable * hash_table)707 g_hash_table_ref (GHashTable *hash_table)
708 {
709 g_return_val_if_fail (hash_table != NULL, NULL);
710 g_return_val_if_fail (hash_table->ref_count > 0, hash_table);
711
712 g_atomic_int_add (&hash_table->ref_count, 1);
713 return hash_table;
714 }
715
716 /**
717 * g_hash_table_unref:
718 * @hash_table: a valid #GHashTable.
719 *
720 * Atomically decrements the reference count of @hash_table by one.
721 * If the reference count drops to 0, all keys and values will be
722 * destroyed, and all memory allocated by the hash table is released.
723 * This function is MT-safe and may be called from any thread.
724 *
725 * Since: 2.10
726 **/
727 void
g_hash_table_unref(GHashTable * hash_table)728 g_hash_table_unref (GHashTable *hash_table)
729 {
730 g_return_if_fail (hash_table != NULL);
731 g_return_if_fail (hash_table->ref_count > 0);
732
733 if (g_atomic_int_exchange_and_add (&hash_table->ref_count, -1) - 1 == 0)
734 {
735 g_hash_table_remove_all_nodes (hash_table, TRUE);
736 g_free (hash_table->nodes);
737 g_slice_free (GHashTable, hash_table);
738 }
739 }
740
741 /**
742 * g_hash_table_destroy:
743 * @hash_table: a #GHashTable.
744 *
745 * Destroys all keys and values in the #GHashTable and decrements its
746 * reference count by 1. If keys and/or values are dynamically allocated,
747 * you should either free them first or create the #GHashTable with destroy
748 * notifiers using g_hash_table_new_full(). In the latter case the destroy
749 * functions you supplied will be called on all keys and values during the
750 * destruction phase.
751 **/
752 void
g_hash_table_destroy(GHashTable * hash_table)753 g_hash_table_destroy (GHashTable *hash_table)
754 {
755 g_return_if_fail (hash_table != NULL);
756 g_return_if_fail (hash_table->ref_count > 0);
757
758 g_hash_table_remove_all (hash_table);
759 g_hash_table_unref (hash_table);
760 }
761
762 /**
763 * g_hash_table_lookup:
764 * @hash_table: a #GHashTable.
765 * @key: the key to look up.
766 *
767 * Looks up a key in a #GHashTable. Note that this function cannot
768 * distinguish between a key that is not present and one which is present
769 * and has the value %NULL. If you need this distinction, use
770 * g_hash_table_lookup_extended().
771 *
772 * Return value: the associated value, or %NULL if the key is not found.
773 **/
774 gpointer
g_hash_table_lookup(GHashTable * hash_table,gconstpointer key)775 g_hash_table_lookup (GHashTable *hash_table,
776 gconstpointer key)
777 {
778 GHashNode *node;
779 guint node_index;
780
781 g_return_val_if_fail (hash_table != NULL, NULL);
782
783 node_index = g_hash_table_lookup_node (hash_table, key);
784 node = &hash_table->nodes [node_index];
785
786 return node->key_hash ? node->value : NULL;
787 }
788
789 /**
790 * g_hash_table_lookup_extended:
791 * @hash_table: a #GHashTable
792 * @lookup_key: the key to look up
793 * @orig_key: return location for the original key, or %NULL
794 * @value: return location for the value associated with the key, or %NULL
795 *
796 * Looks up a key in the #GHashTable, returning the original key and the
797 * associated value and a #gboolean which is %TRUE if the key was found. This
798 * is useful if you need to free the memory allocated for the original key,
799 * for example before calling g_hash_table_remove().
800 *
801 * You can actually pass %NULL for @lookup_key to test
802 * whether the %NULL key exists.
803 *
804 * Return value: %TRUE if the key was found in the #GHashTable.
805 **/
806 gboolean
g_hash_table_lookup_extended(GHashTable * hash_table,gconstpointer lookup_key,gpointer * orig_key,gpointer * value)807 g_hash_table_lookup_extended (GHashTable *hash_table,
808 gconstpointer lookup_key,
809 gpointer *orig_key,
810 gpointer *value)
811 {
812 GHashNode *node;
813 guint node_index;
814
815 g_return_val_if_fail (hash_table != NULL, FALSE);
816
817 node_index = g_hash_table_lookup_node (hash_table, lookup_key);
818 node = &hash_table->nodes [node_index];
819
820 if (!node->key_hash)
821 return FALSE;
822
823 if (orig_key)
824 *orig_key = node->key;
825
826 if (value)
827 *value = node->value;
828
829 return TRUE;
830 }
831
832 /*
833 * g_hash_table_insert_internal:
834 * @hash_table: our #GHashTable
835 * @key: the key to insert
836 * @value: the value to insert
837 * @keep_new_key: if %TRUE and this key already exists in the table
838 * then call the destroy notify function on the old key. If %FALSE
839 * then call the destroy notify function on the new key.
840 *
841 * Implements the common logic for the g_hash_table_insert() and
842 * g_hash_table_replace() functions.
843 *
844 * Do a lookup of @key. If it is found, replace it with the new
845 * @value (and perhaps the new @key). If it is not found, create a
846 * new node.
847 */
848 static void
g_hash_table_insert_internal(GHashTable * hash_table,gpointer key,gpointer value,gboolean keep_new_key)849 g_hash_table_insert_internal (GHashTable *hash_table,
850 gpointer key,
851 gpointer value,
852 gboolean keep_new_key)
853 {
854 GHashNode *node;
855 guint node_index;
856 guint key_hash;
857 guint old_hash;
858
859 g_return_if_fail (hash_table != NULL);
860 g_return_if_fail (hash_table->ref_count > 0);
861
862 node_index = g_hash_table_lookup_node_for_insertion (hash_table, key, &key_hash);
863 node = &hash_table->nodes [node_index];
864
865 old_hash = node->key_hash;
866
867 if (old_hash > 1)
868 {
869 if (keep_new_key)
870 {
871 if (hash_table->key_destroy_func)
872 hash_table->key_destroy_func (node->key);
873 node->key = key;
874 }
875 else
876 {
877 if (hash_table->key_destroy_func)
878 hash_table->key_destroy_func (key);
879 }
880
881 if (hash_table->value_destroy_func)
882 hash_table->value_destroy_func (node->value);
883
884 node->value = value;
885 }
886 else
887 {
888 node->key = key;
889 node->value = value;
890 node->key_hash = key_hash;
891
892 hash_table->nnodes++;
893
894 if (old_hash == 0)
895 {
896 /* We replaced an empty node, and not a tombstone */
897 hash_table->noccupied++;
898 g_hash_table_maybe_resize (hash_table);
899 }
900
901 #ifndef G_DISABLE_ASSERT
902 hash_table->version++;
903 #endif
904 }
905 }
906
907 /**
908 * g_hash_table_insert:
909 * @hash_table: a #GHashTable.
910 * @key: a key to insert.
911 * @value: the value to associate with the key.
912 *
913 * Inserts a new key and value into a #GHashTable.
914 *
915 * If the key already exists in the #GHashTable its current value is replaced
916 * with the new value. If you supplied a @value_destroy_func when creating the
917 * #GHashTable, the old value is freed using that function. If you supplied
918 * a @key_destroy_func when creating the #GHashTable, the passed key is freed
919 * using that function.
920 **/
921 void
g_hash_table_insert(GHashTable * hash_table,gpointer key,gpointer value)922 g_hash_table_insert (GHashTable *hash_table,
923 gpointer key,
924 gpointer value)
925 {
926 g_hash_table_insert_internal (hash_table, key, value, FALSE);
927 }
928
929 /**
930 * g_hash_table_replace:
931 * @hash_table: a #GHashTable.
932 * @key: a key to insert.
933 * @value: the value to associate with the key.
934 *
935 * Inserts a new key and value into a #GHashTable similar to
936 * g_hash_table_insert(). The difference is that if the key already exists
937 * in the #GHashTable, it gets replaced by the new key. If you supplied a
938 * @value_destroy_func when creating the #GHashTable, the old value is freed
939 * using that function. If you supplied a @key_destroy_func when creating the
940 * #GHashTable, the old key is freed using that function.
941 **/
942 void
g_hash_table_replace(GHashTable * hash_table,gpointer key,gpointer value)943 g_hash_table_replace (GHashTable *hash_table,
944 gpointer key,
945 gpointer value)
946 {
947 g_hash_table_insert_internal (hash_table, key, value, TRUE);
948 }
949
950 /*
951 * g_hash_table_remove_internal:
952 * @hash_table: our #GHashTable
953 * @key: the key to remove
954 * @notify: %TRUE if the destroy notify handlers are to be called
955 * Return value: %TRUE if a node was found and removed, else %FALSE
956 *
957 * Implements the common logic for the g_hash_table_remove() and
958 * g_hash_table_steal() functions.
959 *
960 * Do a lookup of @key and remove it if it is found, calling the
961 * destroy notify handlers only if @notify is %TRUE.
962 */
963 static gboolean
g_hash_table_remove_internal(GHashTable * hash_table,gconstpointer key,gboolean notify)964 g_hash_table_remove_internal (GHashTable *hash_table,
965 gconstpointer key,
966 gboolean notify)
967 {
968 GHashNode *node;
969 guint node_index;
970
971 g_return_val_if_fail (hash_table != NULL, FALSE);
972
973 node_index = g_hash_table_lookup_node (hash_table, key);
974 node = &hash_table->nodes [node_index];
975
976 /* g_hash_table_lookup_node() never returns a tombstone, so this is safe */
977 if (!node->key_hash)
978 return FALSE;
979
980 g_hash_table_remove_node (hash_table, node, notify);
981 g_hash_table_maybe_resize (hash_table);
982
983 #ifndef G_DISABLE_ASSERT
984 hash_table->version++;
985 #endif
986
987 return TRUE;
988 }
989
990 /**
991 * g_hash_table_remove:
992 * @hash_table: a #GHashTable.
993 * @key: the key to remove.
994 *
995 * Removes a key and its associated value from a #GHashTable.
996 *
997 * If the #GHashTable was created using g_hash_table_new_full(), the
998 * key and value are freed using the supplied destroy functions, otherwise
999 * you have to make sure that any dynamically allocated values are freed
1000 * yourself.
1001 *
1002 * Return value: %TRUE if the key was found and removed from the #GHashTable.
1003 **/
1004 gboolean
g_hash_table_remove(GHashTable * hash_table,gconstpointer key)1005 g_hash_table_remove (GHashTable *hash_table,
1006 gconstpointer key)
1007 {
1008 return g_hash_table_remove_internal (hash_table, key, TRUE);
1009 }
1010
1011 /**
1012 * g_hash_table_steal:
1013 * @hash_table: a #GHashTable.
1014 * @key: the key to remove.
1015 *
1016 * Removes a key and its associated value from a #GHashTable without
1017 * calling the key and value destroy functions.
1018 *
1019 * Return value: %TRUE if the key was found and removed from the #GHashTable.
1020 **/
1021 gboolean
g_hash_table_steal(GHashTable * hash_table,gconstpointer key)1022 g_hash_table_steal (GHashTable *hash_table,
1023 gconstpointer key)
1024 {
1025 return g_hash_table_remove_internal (hash_table, key, FALSE);
1026 }
1027
1028 /**
1029 * g_hash_table_remove_all:
1030 * @hash_table: a #GHashTable
1031 *
1032 * Removes all keys and their associated values from a #GHashTable.
1033 *
1034 * If the #GHashTable was created using g_hash_table_new_full(), the keys
1035 * and values are freed using the supplied destroy functions, otherwise you
1036 * have to make sure that any dynamically allocated values are freed
1037 * yourself.
1038 *
1039 * Since: 2.12
1040 **/
1041 void
g_hash_table_remove_all(GHashTable * hash_table)1042 g_hash_table_remove_all (GHashTable *hash_table)
1043 {
1044 g_return_if_fail (hash_table != NULL);
1045
1046 #ifndef G_DISABLE_ASSERT
1047 if (hash_table->nnodes != 0)
1048 hash_table->version++;
1049 #endif
1050
1051 g_hash_table_remove_all_nodes (hash_table, TRUE);
1052 g_hash_table_maybe_resize (hash_table);
1053 }
1054
1055 /**
1056 * g_hash_table_steal_all:
1057 * @hash_table: a #GHashTable.
1058 *
1059 * Removes all keys and their associated values from a #GHashTable
1060 * without calling the key and value destroy functions.
1061 *
1062 * Since: 2.12
1063 **/
1064 void
g_hash_table_steal_all(GHashTable * hash_table)1065 g_hash_table_steal_all (GHashTable *hash_table)
1066 {
1067 g_return_if_fail (hash_table != NULL);
1068
1069 #ifndef G_DISABLE_ASSERT
1070 if (hash_table->nnodes != 0)
1071 hash_table->version++;
1072 #endif
1073
1074 g_hash_table_remove_all_nodes (hash_table, FALSE);
1075 g_hash_table_maybe_resize (hash_table);
1076 }
1077
1078 /*
1079 * g_hash_table_foreach_remove_or_steal:
1080 * @hash_table: our #GHashTable
1081 * @func: the user's callback function
1082 * @user_data: data for @func
1083 * @notify: %TRUE if the destroy notify handlers are to be called
1084 *
1085 * Implements the common logic for g_hash_table_foreach_remove() and
1086 * g_hash_table_foreach_steal().
1087 *
1088 * Iterates over every node in the table, calling @func with the key
1089 * and value of the node (and @user_data). If @func returns %TRUE the
1090 * node is removed from the table.
1091 *
1092 * If @notify is true then the destroy notify handlers will be called
1093 * for each removed node.
1094 */
1095 static guint
g_hash_table_foreach_remove_or_steal(GHashTable * hash_table,GHRFunc func,gpointer user_data,gboolean notify)1096 g_hash_table_foreach_remove_or_steal (GHashTable *hash_table,
1097 GHRFunc func,
1098 gpointer user_data,
1099 gboolean notify)
1100 {
1101 guint deleted = 0;
1102 gint i;
1103
1104 for (i = 0; i < hash_table->size; i++)
1105 {
1106 GHashNode *node = &hash_table->nodes [i];
1107
1108 if (node->key_hash > 1 && (* func) (node->key, node->value, user_data))
1109 {
1110 g_hash_table_remove_node (hash_table, node, notify);
1111 deleted++;
1112 }
1113 }
1114
1115 g_hash_table_maybe_resize (hash_table);
1116
1117 #ifndef G_DISABLE_ASSERT
1118 if (deleted > 0)
1119 hash_table->version++;
1120 #endif
1121
1122 return deleted;
1123 }
1124
1125 /**
1126 * g_hash_table_foreach_remove:
1127 * @hash_table: a #GHashTable.
1128 * @func: the function to call for each key/value pair.
1129 * @user_data: user data to pass to the function.
1130 *
1131 * Calls the given function for each key/value pair in the #GHashTable.
1132 * If the function returns %TRUE, then the key/value pair is removed from the
1133 * #GHashTable. If you supplied key or value destroy functions when creating
1134 * the #GHashTable, they are used to free the memory allocated for the removed
1135 * keys and values.
1136 *
1137 * See #GHashTableIter for an alternative way to loop over the
1138 * key/value pairs in the hash table.
1139 *
1140 * Return value: the number of key/value pairs removed.
1141 **/
1142 guint
g_hash_table_foreach_remove(GHashTable * hash_table,GHRFunc func,gpointer user_data)1143 g_hash_table_foreach_remove (GHashTable *hash_table,
1144 GHRFunc func,
1145 gpointer user_data)
1146 {
1147 g_return_val_if_fail (hash_table != NULL, 0);
1148 g_return_val_if_fail (func != NULL, 0);
1149
1150 return g_hash_table_foreach_remove_or_steal (hash_table, func, user_data, TRUE);
1151 }
1152
1153 /**
1154 * g_hash_table_foreach_steal:
1155 * @hash_table: a #GHashTable.
1156 * @func: the function to call for each key/value pair.
1157 * @user_data: user data to pass to the function.
1158 *
1159 * Calls the given function for each key/value pair in the #GHashTable.
1160 * If the function returns %TRUE, then the key/value pair is removed from the
1161 * #GHashTable, but no key or value destroy functions are called.
1162 *
1163 * See #GHashTableIter for an alternative way to loop over the
1164 * key/value pairs in the hash table.
1165 *
1166 * Return value: the number of key/value pairs removed.
1167 **/
1168 guint
g_hash_table_foreach_steal(GHashTable * hash_table,GHRFunc func,gpointer user_data)1169 g_hash_table_foreach_steal (GHashTable *hash_table,
1170 GHRFunc func,
1171 gpointer user_data)
1172 {
1173 g_return_val_if_fail (hash_table != NULL, 0);
1174 g_return_val_if_fail (func != NULL, 0);
1175
1176 return g_hash_table_foreach_remove_or_steal (hash_table, func, user_data, FALSE);
1177 }
1178
1179 /**
1180 * g_hash_table_foreach:
1181 * @hash_table: a #GHashTable.
1182 * @func: the function to call for each key/value pair.
1183 * @user_data: user data to pass to the function.
1184 *
1185 * Calls the given function for each of the key/value pairs in the
1186 * #GHashTable. The function is passed the key and value of each
1187 * pair, and the given @user_data parameter. The hash table may not
1188 * be modified while iterating over it (you can't add/remove
1189 * items). To remove all items matching a predicate, use
1190 * g_hash_table_foreach_remove().
1191 *
1192 * See g_hash_table_find() for performance caveats for linear
1193 * order searches in contrast to g_hash_table_lookup().
1194 **/
1195 void
g_hash_table_foreach(GHashTable * hash_table,GHFunc func,gpointer user_data)1196 g_hash_table_foreach (GHashTable *hash_table,
1197 GHFunc func,
1198 gpointer user_data)
1199 {
1200 gint i;
1201
1202 g_return_if_fail (hash_table != NULL);
1203 g_return_if_fail (func != NULL);
1204
1205 for (i = 0; i < hash_table->size; i++)
1206 {
1207 GHashNode *node = &hash_table->nodes [i];
1208
1209 if (node->key_hash > 1)
1210 (* func) (node->key, node->value, user_data);
1211 }
1212 }
1213
1214 /**
1215 * g_hash_table_find:
1216 * @hash_table: a #GHashTable.
1217 * @predicate: function to test the key/value pairs for a certain property.
1218 * @user_data: user data to pass to the function.
1219 *
1220 * Calls the given function for key/value pairs in the #GHashTable until
1221 * @predicate returns %TRUE. The function is passed the key and value of
1222 * each pair, and the given @user_data parameter. The hash table may not
1223 * be modified while iterating over it (you can't add/remove items).
1224 *
1225 * Note, that hash tables are really only optimized for forward lookups,
1226 * i.e. g_hash_table_lookup().
1227 * So code that frequently issues g_hash_table_find() or
1228 * g_hash_table_foreach() (e.g. in the order of once per every entry in a
1229 * hash table) should probably be reworked to use additional or different
1230 * data structures for reverse lookups (keep in mind that an O(n) find/foreach
1231 * operation issued for all n values in a hash table ends up needing O(n*n)
1232 * operations).
1233 *
1234 * Return value: The value of the first key/value pair is returned, for which
1235 * func evaluates to %TRUE. If no pair with the requested property is found,
1236 * %NULL is returned.
1237 *
1238 * Since: 2.4
1239 **/
1240 gpointer
g_hash_table_find(GHashTable * hash_table,GHRFunc predicate,gpointer user_data)1241 g_hash_table_find (GHashTable *hash_table,
1242 GHRFunc predicate,
1243 gpointer user_data)
1244 {
1245 gint i;
1246
1247 g_return_val_if_fail (hash_table != NULL, NULL);
1248 g_return_val_if_fail (predicate != NULL, NULL);
1249
1250 for (i = 0; i < hash_table->size; i++)
1251 {
1252 GHashNode *node = &hash_table->nodes [i];
1253
1254 if (node->key_hash > 1 && predicate (node->key, node->value, user_data))
1255 return node->value;
1256 }
1257
1258 return NULL;
1259 }
1260
1261 /**
1262 * g_hash_table_size:
1263 * @hash_table: a #GHashTable.
1264 *
1265 * Returns the number of elements contained in the #GHashTable.
1266 *
1267 * Return value: the number of key/value pairs in the #GHashTable.
1268 **/
1269 guint
g_hash_table_size(GHashTable * hash_table)1270 g_hash_table_size (GHashTable *hash_table)
1271 {
1272 g_return_val_if_fail (hash_table != NULL, 0);
1273
1274 return hash_table->nnodes;
1275 }
1276
1277 /**
1278 * g_hash_table_get_keys:
1279 * @hash_table: a #GHashTable
1280 *
1281 * Retrieves every key inside @hash_table. The returned data is valid
1282 * until @hash_table is modified.
1283 *
1284 * Return value: a #GList containing all the keys inside the hash
1285 * table. The content of the list is owned by the hash table and
1286 * should not be modified or freed. Use g_list_free() when done
1287 * using the list.
1288 *
1289 * Since: 2.14
1290 */
1291 GList *
g_hash_table_get_keys(GHashTable * hash_table)1292 g_hash_table_get_keys (GHashTable *hash_table)
1293 {
1294 gint i;
1295 GList *retval;
1296
1297 g_return_val_if_fail (hash_table != NULL, NULL);
1298
1299 retval = NULL;
1300 for (i = 0; i < hash_table->size; i++)
1301 {
1302 GHashNode *node = &hash_table->nodes [i];
1303
1304 if (node->key_hash > 1)
1305 retval = g_list_prepend (retval, node->key);
1306 }
1307
1308 return retval;
1309 }
1310
1311 /**
1312 * g_hash_table_get_values:
1313 * @hash_table: a #GHashTable
1314 *
1315 * Retrieves every value inside @hash_table. The returned data is
1316 * valid until @hash_table is modified.
1317 *
1318 * Return value: a #GList containing all the values inside the hash
1319 * table. The content of the list is owned by the hash table and
1320 * should not be modified or freed. Use g_list_free() when done
1321 * using the list.
1322 *
1323 * Since: 2.14
1324 */
1325 GList *
g_hash_table_get_values(GHashTable * hash_table)1326 g_hash_table_get_values (GHashTable *hash_table)
1327 {
1328 gint i;
1329 GList *retval;
1330
1331 g_return_val_if_fail (hash_table != NULL, NULL);
1332
1333 retval = NULL;
1334 for (i = 0; i < hash_table->size; i++)
1335 {
1336 GHashNode *node = &hash_table->nodes [i];
1337
1338 if (node->key_hash > 1)
1339 retval = g_list_prepend (retval, node->value);
1340 }
1341
1342 return retval;
1343 }
1344
1345 #define __G_HASH_C__
1346 #include "galiasdef.c"
1347