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1/*
2 This file is part of GNUnet.
3 Copyright (C) 2008, 2012 GNUnet e.V.
4
5 GNUnet is free software: you can redistribute it and/or modify it
6 under the terms of the GNU Affero General Public License as published
7 by the Free Software Foundation, either version 3 of the License,
8 or (at your option) any later version.
9
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Affero General Public License for more details.
14
15 You should have received a copy of the GNU Affero General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
17
18 SPDX-License-Identifier: AGPL3.0-or-later
19*/
20/**
21 * @file util/container_multiuuidmap.c
22 * @brief hash map for UUIDs where the same key may be present multiple times
23 * @author Christian Grothoff
24 */
25
26#include "platform.h"
27#include "gnunet_util_lib.h"
28
29#define LOG(kind, ...) \
30 GNUNET_log_from (kind, "util-container-multiuuidmap", __VA_ARGS__)
31
32/**
33 * Maximum recursion depth for callbacks of
34 * #GNUNET_CONTAINER_multihashmap_get_multiple() themselve s
35 * again calling #GNUNET_CONTAINER_multihashmap_get_multiple().
36 * Should be totally excessive, but if violated we die.
37 */
38#define NEXT_CACHE_SIZE 16
39
40
41/**
42 * An entry in the hash map with the full key.
43 */
44struct BigMapEntry
45{
46
47 /**
48 * Value of the entry.
49 */
50 void *value;
51
52 /**
53 * If there is a hash collision, we create a linked list.
54 */
55 struct BigMapEntry *next;
56
57 /**
58 * Key for the entry.
59 */
60 struct GNUNET_Uuid key;
61};
62
63
64/**
65 * An entry in the hash map with just a pointer to the key.
66 */
67struct SmallMapEntry
68{
69
70 /**
71 * Value of the entry.
72 */
73 void *value;
74
75 /**
76 * If there is a hash collision, we create a linked list.
77 */
78 struct SmallMapEntry *next;
79
80 /**
81 * Key for the entry.
82 */
83 const struct GNUNET_Uuid *key;
84};
85
86
87/**
88 * Entry in the map.
89 */
90union MapEntry
91{
92 /**
93 * Variant used if map entries only contain a pointer to the key.
94 */
95 struct SmallMapEntry *sme;
96
97 /**
98 * Variant used if map entries contain the full key.
99 */
100 struct BigMapEntry *bme;
101};
102
103
104/**
105 * Internal representation of the hash map.
106 */
107struct GNUNET_CONTAINER_MultiUuidmap
108{
109 /**
110 * All of our buckets.
111 */
112 union MapEntry *map;
113
114 /**
115 * Number of entries in the map.
116 */
117 unsigned int size;
118
119 /**
120 * Length of the "map" array.
121 */
122 unsigned int map_length;
123
124 /**
125 * #GNUNET_NO if the map entries are of type 'struct BigMapEntry',
126 * #GNUNET_YES if the map entries are of type 'struct SmallMapEntry'.
127 */
128 int use_small_entries;
129
130 /**
131 * Counts the destructive modifications (grow, remove)
132 * to the map, so that iterators can check if they are still valid.
133 */
134 unsigned int modification_counter;
135
136 /**
137 * Map entries indicating iteration positions currently
138 * in use by #GNUNET_CONTAINER_multihashmap_get_multiple().
139 * Only used up to @e next_cache_off.
140 */
141 union MapEntry next_cache[NEXT_CACHE_SIZE];
142
143 /**
144 * Offset of @e next_cache entries in use, must be smaller
145 * than #NEXT_CACHE_SIZE.
146 */
147 unsigned int next_cache_off;
148};
149
150
151/**
152 * Cursor into a multiuuidmap.
153 * Allows to enumerate elements asynchronously.
154 */
155struct GNUNET_CONTAINER_MultiUuidmapIterator
156{
157 /**
158 * Position in the bucket 'idx'
159 */
160 union MapEntry me;
161
162 /**
163 * Current bucket index.
164 */
165 unsigned int idx;
166
167 /**
168 * Modification counter as observed on the map when the iterator
169 * was created.
170 */
171 unsigned int modification_counter;
172
173 /**
174 * Map that we are iterating over.
175 */
176 const struct GNUNET_CONTAINER_MultiUuidmap *map;
177};
178
179
180/**
181 * Create a multi hash map.
182 *
183 * @param len initial size (map will grow as needed)
184 * @param do_not_copy_keys #GNUNET_NO is always safe and should be used by default;
185 * #GNUNET_YES means that on 'put', the 'key' does not have
186 * to be copied as the destination of the pointer is
187 * guaranteed to be life as long as the value is stored in
188 * the hashmap. This can significantly reduce memory
189 * consumption, but of course is also a recipie for
190 * heap corruption if the assumption is not true. Only
191 * use this if (1) memory use is important in this case and
192 * (2) you have triple-checked that the invariant holds
193 * @return NULL on error
194 */
195struct GNUNET_CONTAINER_MultiUuidmap *
196GNUNET_CONTAINER_multiuuidmap_create (unsigned int len, int do_not_copy_keys)
197{
198 struct GNUNET_CONTAINER_MultiUuidmap *map;
199
200 GNUNET_assert (len > 0);
201 map = GNUNET_new (struct GNUNET_CONTAINER_MultiUuidmap);
202 map->map = GNUNET_malloc_large (len * sizeof (union MapEntry));
203 if (NULL == map->map)
204 {
205 GNUNET_free (map);
206 return NULL;
207 }
208 map->map_length = len;
209 map->use_small_entries = do_not_copy_keys;
210 return map;
211}
212
213
214/**
215 * Destroy a hash map. Will not free any values
216 * stored in the hash map!
217 *
218 * @param map the map
219 */
220void
221GNUNET_CONTAINER_multiuuidmap_destroy (
222 struct GNUNET_CONTAINER_MultiUuidmap *map)
223{
224 GNUNET_assert (0 == map->next_cache_off);
225 for (unsigned int i = 0; i < map->map_length; i++)
226 {
227 union MapEntry me;
228
229 me = map->map[i];
230 if (map->use_small_entries)
231 {
232 struct SmallMapEntry *sme;
233 struct SmallMapEntry *nxt;
234
235 nxt = me.sme;
236 while (NULL != (sme = nxt))
237 {
238 nxt = sme->next;
239 GNUNET_free (sme);
240 }
241 me.sme = NULL;
242 }
243 else
244 {
245 struct BigMapEntry *bme;
246 struct BigMapEntry *nxt;
247
248 nxt = me.bme;
249 while (NULL != (bme = nxt))
250 {
251 nxt = bme->next;
252 GNUNET_free (bme);
253 }
254 me.bme = NULL;
255 }
256 }
257 GNUNET_free (map->map);
258 GNUNET_free (map);
259}
260
261
262/**
263 * Compute the index of the bucket for the given key.
264 *
265 * @param map hash map for which to compute the index
266 * @param key what key should the index be computed for
267 * @return offset into the "map" array of "map"
268 */
269static unsigned int
270idx_of (const struct GNUNET_CONTAINER_MultiUuidmap *map,
271 const struct GNUNET_Uuid *key)
272{
273 unsigned int kx;
274
275 GNUNET_assert (NULL != map);
276 GNUNET_memcpy (&kx, key, sizeof (kx));
277 return kx % map->map_length;
278}
279
280
281/**
282 * Get the number of key-value pairs in the map.
283 *
284 * @param map the map
285 * @return the number of key value pairs
286 */
287unsigned int
288GNUNET_CONTAINER_multiuuidmap_size (
289 const struct GNUNET_CONTAINER_MultiUuidmap *map)
290{
291 return map->size;
292}
293
294
295/**
296 * Given a key find a value in the map matching the key.
297 *
298 * @param map the map
299 * @param key what to look for
300 * @return NULL if no value was found; note that
301 * this is indistinguishable from values that just
302 * happen to be NULL; use "contains" to test for
303 * key-value pairs with value NULL
304 */
305void *
306GNUNET_CONTAINER_multiuuidmap_get (
307 const struct GNUNET_CONTAINER_MultiUuidmap *map,
308 const struct GNUNET_Uuid *key)
309{
310 union MapEntry me;
311
312 me = map->map[idx_of (map, key)];
313 if (map->use_small_entries)
314 {
315 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
316 if (0 == GNUNET_memcmp (key, sme->key))
317 return sme->value;
318 }
319 else
320 {
321 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
322 if (0 == GNUNET_memcmp (key, &bme->key))
323 return bme->value;
324 }
325 return NULL;
326}
327
328
329/**
330 * Iterate over all entries in the map.
331 *
332 * @param map the map
333 * @param it function to call on each entry
334 * @param it_cls extra argument to @a it
335 * @return the number of key value pairs processed,
336 * #GNUNET_SYSERR if it aborted iteration
337 */
338int
339GNUNET_CONTAINER_multiuuidmap_iterate (
340 struct GNUNET_CONTAINER_MultiUuidmap *map,
341 GNUNET_CONTAINER_MultiUuidmapIterator it,
342 void *it_cls)
343{
344 int count;
345 union MapEntry me;
346 union MapEntry *ce;
347 struct GNUNET_Uuid kc;
348
349 count = 0;
350 GNUNET_assert (NULL != map);
351 ce = &map->next_cache[map->next_cache_off];
352 GNUNET_assert (++map->next_cache_off < NEXT_CACHE_SIZE);
353 for (unsigned int i = 0; i < map->map_length; i++)
354 {
355 me = map->map[i];
356 if (map->use_small_entries)
357 {
358 struct SmallMapEntry *sme;
359
360 ce->sme = me.sme;
361 while (NULL != (sme = ce->sme))
362 {
363 ce->sme = sme->next;
364 if ((NULL != it) && (GNUNET_OK != it (it_cls, sme->key, sme->value)))
365 {
366 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
367 return GNUNET_SYSERR;
368 }
369 count++;
370 }
371 }
372 else
373 {
374 struct BigMapEntry *bme;
375
376 ce->bme = me.bme;
377 while (NULL != (bme = ce->bme))
378 {
379 ce->bme = bme->next;
380 if (NULL != it)
381 {
382 kc = bme->key;
383 if (GNUNET_OK != it (it_cls, &kc, bme->value))
384 {
385 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
386 return GNUNET_SYSERR;
387 }
388 }
389 count++;
390 }
391 }
392 }
393 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
394 return count;
395}
396
397
398/**
399 * We are about to free() the @a bme, make sure it is not in
400 * the list of next values for any iterator in the @a map's next_cache.
401 *
402 * @param map the map to check
403 * @param bme the entry that is about to be free'd
404 */
405static void
406update_next_cache_bme (struct GNUNET_CONTAINER_MultiUuidmap *map,
407 const struct BigMapEntry *bme)
408{
409 for (unsigned int i = 0; i < map->next_cache_off; i++)
410 if (map->next_cache[i].bme == bme)
411 map->next_cache[i].bme = bme->next;
412}
413
414
415/**
416 * We are about to free() the @a sme, make sure it is not in
417 * the list of next values for any iterator in the @a map's next_cache.
418 *
419 * @param map the map to check
420 * @param sme the entry that is about to be free'd
421 */
422static void
423update_next_cache_sme (struct GNUNET_CONTAINER_MultiUuidmap *map,
424 const struct SmallMapEntry *sme)
425{
426 for (unsigned int i = 0; i < map->next_cache_off; i++)
427 if (map->next_cache[i].sme == sme)
428 map->next_cache[i].sme = sme->next;
429}
430
431
432/**
433 * Remove the given key-value pair from the map. Note that if the
434 * key-value pair is in the map multiple times, only one of the pairs
435 * will be removed.
436 *
437 * @param map the map
438 * @param key key of the key-value pair
439 * @param value value of the key-value pair
440 * @return #GNUNET_YES on success, #GNUNET_NO if the key-value pair
441 * is not in the map
442 */
443int
444GNUNET_CONTAINER_multiuuidmap_remove (struct GNUNET_CONTAINER_MultiUuidmap *map,
445 const struct GNUNET_Uuid *key,
446 const void *value)
447{
448 union MapEntry me;
449 unsigned int i;
450
451 map->modification_counter++;
452 i = idx_of (map, key);
453 me = map->map[i];
454 if (map->use_small_entries)
455 {
456 struct SmallMapEntry *p = NULL;
457
458 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
459 {
460 if ((0 == GNUNET_memcmp (key, sme->key)) && (value == sme->value))
461 {
462 if (NULL == p)
463 map->map[i].sme = sme->next;
464 else
465 p->next = sme->next;
466 update_next_cache_sme (map, sme);
467 GNUNET_free (sme);
468 map->size--;
469 return GNUNET_YES;
470 }
471 p = sme;
472 }
473 }
474 else
475 {
476 struct BigMapEntry *p = NULL;
477
478 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
479 {
480 if ((0 == GNUNET_memcmp (key, &bme->key)) && (value == bme->value))
481 {
482 if (NULL == p)
483 map->map[i].bme = bme->next;
484 else
485 p->next = bme->next;
486 update_next_cache_bme (map, bme);
487 GNUNET_free (bme);
488 map->size--;
489 return GNUNET_YES;
490 }
491 p = bme;
492 }
493 }
494 return GNUNET_NO;
495}
496
497
498/**
499 * Remove all entries for the given key from the map.
500 * Note that the values would not be "freed".
501 *
502 * @param map the map
503 * @param key identifies values to be removed
504 * @return number of values removed
505 */
506int
507GNUNET_CONTAINER_multiuuidmap_remove_all (
508 struct GNUNET_CONTAINER_MultiUuidmap *map,
509 const struct GNUNET_Uuid *key)
510{
511 union MapEntry me;
512 unsigned int i;
513 int ret;
514
515 map->modification_counter++;
516
517 ret = 0;
518 i = idx_of (map, key);
519 me = map->map[i];
520 if (map->use_small_entries)
521 {
522 struct SmallMapEntry *sme;
523 struct SmallMapEntry *p;
524
525 p = NULL;
526 sme = me.sme;
527 while (NULL != sme)
528 {
529 if (0 == GNUNET_memcmp (key, sme->key))
530 {
531 if (NULL == p)
532 map->map[i].sme = sme->next;
533 else
534 p->next = sme->next;
535 update_next_cache_sme (map, sme);
536 GNUNET_free (sme);
537 map->size--;
538 if (NULL == p)
539 sme = map->map[i].sme;
540 else
541 sme = p->next;
542 ret++;
543 }
544 else
545 {
546 p = sme;
547 sme = sme->next;
548 }
549 }
550 }
551 else
552 {
553 struct BigMapEntry *bme;
554 struct BigMapEntry *p;
555
556 p = NULL;
557 bme = me.bme;
558 while (NULL != bme)
559 {
560 if (0 == GNUNET_memcmp (key, &bme->key))
561 {
562 if (NULL == p)
563 map->map[i].bme = bme->next;
564 else
565 p->next = bme->next;
566 update_next_cache_bme (map, bme);
567 GNUNET_free (bme);
568 map->size--;
569 if (NULL == p)
570 bme = map->map[i].bme;
571 else
572 bme = p->next;
573 ret++;
574 }
575 else
576 {
577 p = bme;
578 bme = bme->next;
579 }
580 }
581 }
582 return ret;
583}
584
585
586/**
587 * Check if the map contains any value under the given
588 * key (including values that are NULL).
589 *
590 * @param map the map
591 * @param key the key to test if a value exists for it
592 * @return #GNUNET_YES if such a value exists,
593 * #GNUNET_NO if not
594 */
595int
596GNUNET_CONTAINER_multiuuidmap_contains (
597 const struct GNUNET_CONTAINER_MultiUuidmap *map,
598 const struct GNUNET_Uuid *key)
599{
600 union MapEntry me;
601
602 me = map->map[idx_of (map, key)];
603 if (map->use_small_entries)
604 {
605 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
606 if (0 == GNUNET_memcmp (key, sme->key))
607 return GNUNET_YES;
608 }
609 else
610 {
611 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
612 if (0 == GNUNET_memcmp (key, &bme->key))
613 return GNUNET_YES;
614 }
615 return GNUNET_NO;
616}
617
618
619/**
620 * Check if the map contains the given value under the given
621 * key.
622 *
623 * @param map the map
624 * @param key the key to test if a value exists for it
625 * @param value value to test for
626 * @return #GNUNET_YES if such a value exists,
627 * #GNUNET_NO if not
628 */
629int
630GNUNET_CONTAINER_multiuuidmap_contains_value (
631 const struct GNUNET_CONTAINER_MultiUuidmap *map,
632 const struct GNUNET_Uuid *key,
633 const void *value)
634{
635 union MapEntry me;
636
637 me = map->map[idx_of (map, key)];
638 if (map->use_small_entries)
639 {
640 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
641 if ((0 == GNUNET_memcmp (key, sme->key)) && (sme->value == value))
642 return GNUNET_YES;
643 }
644 else
645 {
646 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
647 if ((0 == GNUNET_memcmp (key, &bme->key)) && (bme->value == value))
648 return GNUNET_YES;
649 }
650 return GNUNET_NO;
651}
652
653
654/**
655 * Grow the given map to a more appropriate size.
656 *
657 * @param map the hash map to grow
658 */
659static void
660grow (struct GNUNET_CONTAINER_MultiUuidmap *map)
661{
662 union MapEntry *old_map;
663 union MapEntry *new_map;
664 unsigned int old_len;
665 unsigned int new_len;
666 unsigned int idx;
667
668 old_map = map->map;
669 old_len = map->map_length;
670 new_len = old_len * 2;
671 if (0 == new_len) /* 2^31 * 2 == 0 */
672 new_len = old_len; /* never use 0 */
673 if (new_len == old_len)
674 return; /* nothing changed */
675 new_map = GNUNET_malloc_large (new_len * sizeof (union MapEntry));
676 if (NULL == new_map)
677 return; /* grow not possible */
678 map->modification_counter++;
679 map->map_length = new_len;
680 map->map = new_map;
681 for (unsigned int i = 0; i < old_len; i++)
682 {
683 if (map->use_small_entries)
684 {
685 struct SmallMapEntry *sme;
686
687 while (NULL != (sme = old_map[i].sme))
688 {
689 old_map[i].sme = sme->next;
690 idx = idx_of (map, sme->key);
691 sme->next = new_map[idx].sme;
692 new_map[idx].sme = sme;
693 }
694 }
695 else
696 {
697 struct BigMapEntry *bme;
698
699 while (NULL != (bme = old_map[i].bme))
700 {
701 old_map[i].bme = bme->next;
702 idx = idx_of (map, &bme->key);
703 bme->next = new_map[idx].bme;
704 new_map[idx].bme = bme;
705 }
706 }
707 }
708 GNUNET_free (old_map);
709}
710
711
712/**
713 * Store a key-value pair in the map.
714 *
715 * @param map the map
716 * @param key key to use
717 * @param value value to use
718 * @param opt options for put
719 * @return #GNUNET_OK on success,
720 * #GNUNET_NO if a value was replaced (with REPLACE)
721 * #GNUNET_SYSERR if #GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY was the option and the
722 * value already exists
723 */
724int
725GNUNET_CONTAINER_multiuuidmap_put (struct GNUNET_CONTAINER_MultiUuidmap *map,
726 const struct GNUNET_Uuid *key,
727 void *value,
728 enum GNUNET_CONTAINER_MultiHashMapOption opt)
729{
730 union MapEntry me;
731 unsigned int i;
732
733 i = idx_of (map, key);
734 if ((opt != GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE) &&
735 (opt != GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST))
736 {
737 me = map->map[i];
738 if (map->use_small_entries)
739 {
740 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
741 if (0 == GNUNET_memcmp (key, sme->key))
742 {
743 if (opt == GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)
744 return GNUNET_SYSERR;
745 sme->value = value;
746 return GNUNET_NO;
747 }
748 }
749 else
750 {
751 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
752 if (0 == GNUNET_memcmp (key, &bme->key))
753 {
754 if (opt == GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)
755 return GNUNET_SYSERR;
756 bme->value = value;
757 return GNUNET_NO;
758 }
759 }
760 }
761 if (map->size / 3 >= map->map_length / 4)
762 {
763 grow (map);
764 i = idx_of (map, key);
765 }
766 if (map->use_small_entries)
767 {
768 struct SmallMapEntry *sme;
769
770 sme = GNUNET_new (struct SmallMapEntry);
771 sme->key = key;
772 sme->value = value;
773 sme->next = map->map[i].sme;
774 map->map[i].sme = sme;
775 }
776 else
777 {
778 struct BigMapEntry *bme;
779
780 bme = GNUNET_new (struct BigMapEntry);
781 bme->key = *key;
782 bme->value = value;
783 bme->next = map->map[i].bme;
784 map->map[i].bme = bme;
785 }
786 map->size++;
787 return GNUNET_OK;
788}
789
790
791/**
792 * Iterate over all entries in the map that match a particular key.
793 *
794 * @param map the map
795 * @param key key that the entries must correspond to
796 * @param it function to call on each entry
797 * @param it_cls extra argument to @a it
798 * @return the number of key value pairs processed,
799 * #GNUNET_SYSERR if it aborted iteration
800 */
801int
802GNUNET_CONTAINER_multiuuidmap_get_multiple (
803 struct GNUNET_CONTAINER_MultiUuidmap *map,
804 const struct GNUNET_Uuid *key,
805 GNUNET_CONTAINER_MultiUuidmapIterator it,
806 void *it_cls)
807{
808 int count;
809 union MapEntry me;
810 union MapEntry *ce;
811
812 ce = &map->next_cache[map->next_cache_off];
813 GNUNET_assert (++map->next_cache_off < NEXT_CACHE_SIZE);
814 count = 0;
815 me = map->map[idx_of (map, key)];
816 if (map->use_small_entries)
817 {
818 struct SmallMapEntry *sme;
819
820 ce->sme = me.sme;
821 while (NULL != (sme = ce->sme))
822 {
823 ce->sme = sme->next;
824 if (0 != GNUNET_memcmp (key, sme->key))
825 continue;
826 if ((NULL != it) && (GNUNET_OK != it (it_cls, key, sme->value)))
827 {
828 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
829 return GNUNET_SYSERR;
830 }
831 count++;
832 }
833 }
834 else
835 {
836 struct BigMapEntry *bme;
837
838 ce->bme = me.bme;
839 while (NULL != (bme = ce->bme))
840 {
841 ce->bme = bme->next;
842 if (0 != GNUNET_memcmp (key, &bme->key))
843 continue;
844 if ((NULL != it) && (GNUNET_OK != it (it_cls, key, bme->value)))
845 {
846 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
847 return GNUNET_SYSERR;
848 }
849 count++;
850 }
851 }
852 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
853 return count;
854}
855
856
857/**
858 * @ingroup hashmap
859 * Call @a it on a random value from the map, or not at all
860 * if the map is empty. Note that this function has linear
861 * complexity (in the size of the map).
862 *
863 * @param map the map
864 * @param it function to call on a random entry
865 * @param it_cls extra argument to @a it
866 * @return the number of key value pairs processed, zero or one.
867 */
868unsigned int
869GNUNET_CONTAINER_multiuuidmap_get_random (
870 const struct GNUNET_CONTAINER_MultiUuidmap *map,
871 GNUNET_CONTAINER_MultiUuidmapIterator it,
872 void *it_cls)
873{
874 unsigned int off;
875 union MapEntry me;
876
877 if (0 == map->size)
878 return 0;
879 if (NULL == it)
880 return 1;
881 off = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, map->size);
882 for (unsigned int idx = 0; idx < map->map_length; idx++)
883 {
884 me = map->map[idx];
885 if (map->use_small_entries)
886 {
887 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
888 {
889 if (0 == off)
890 {
891 if (GNUNET_OK != it (it_cls, sme->key, sme->value))
892 return GNUNET_SYSERR;
893 return 1;
894 }
895 off--;
896 }
897 }
898 else
899 {
900 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
901 {
902 if (0 == off)
903 {
904 if (GNUNET_OK != it (it_cls, &bme->key, bme->value))
905 return GNUNET_SYSERR;
906 return 1;
907 }
908 off--;
909 }
910 }
911 }
912 GNUNET_break (0);
913 return GNUNET_SYSERR;
914}
915
916
917/**
918 * Create an iterator for a multiuuidmap.
919 * The iterator can be used to retrieve all the elements in the multiuuidmap
920 * one by one, without having to handle all elements at once (in contrast to
921 * #GNUNET_CONTAINER_multiuuidmap_iterate). Note that the iterator can not be
922 * used anymore if elements have been removed from 'map' after the creation of
923 * the iterator, or 'map' has been destroyed. Adding elements to 'map' may
924 * result in skipped or repeated elements.
925 *
926 * @param map the map to create an iterator for
927 * @return an iterator over the given multiuuidmap 'map'
928 */
929struct GNUNET_CONTAINER_MultiUuidmapIterator *
930GNUNET_CONTAINER_multiuuidmap_iterator_create (
931 const struct GNUNET_CONTAINER_MultiUuidmap *map)
932{
933 struct GNUNET_CONTAINER_MultiUuidmapIterator *iter;
934
935 iter = GNUNET_new (struct GNUNET_CONTAINER_MultiUuidmapIterator);
936 iter->map = map;
937 iter->modification_counter = map->modification_counter;
938 iter->me = map->map[0];
939 return iter;
940}
941
942
943/**
944 * Retrieve the next element from the hash map at the iterator's position.
945 * If there are no elements left, GNUNET_NO is returned, and 'key' and 'value'
946 * are not modified.
947 * This operation is only allowed if no elements have been removed from the
948 * multiuuidmap since the creation of 'iter', and the map has not been destroyed.
949 * Adding elements may result in repeating or skipping elements.
950 *
951 * @param iter the iterator to get the next element from
952 * @param key pointer to store the key in, can be NULL
953 * @param value pointer to store the value in, can be NULL
954 * @return #GNUNET_YES we returned an element,
955 * #GNUNET_NO if we are out of elements
956 */
957int
958GNUNET_CONTAINER_multiuuidmap_iterator_next (
959 struct GNUNET_CONTAINER_MultiUuidmapIterator *iter,
960 struct GNUNET_Uuid *key,
961 const void **value)
962{
963 /* make sure the map has not been modified */
964 GNUNET_assert (iter->modification_counter == iter->map->modification_counter);
965
966 /* look for the next entry, skipping empty buckets */
967 while (1)
968 {
969 if (iter->idx >= iter->map->map_length)
970 return GNUNET_NO;
971 if (GNUNET_YES == iter->map->use_small_entries)
972 {
973 if (NULL != iter->me.sme)
974 {
975 if (NULL != key)
976 *key = *iter->me.sme->key;
977 if (NULL != value)
978 *value = iter->me.sme->value;
979 iter->me.sme = iter->me.sme->next;
980 return GNUNET_YES;
981 }
982 }
983 else
984 {
985 if (NULL != iter->me.bme)
986 {
987 if (NULL != key)
988 *key = iter->me.bme->key;
989 if (NULL != value)
990 *value = iter->me.bme->value;
991 iter->me.bme = iter->me.bme->next;
992 return GNUNET_YES;
993 }
994 }
995 iter->idx += 1;
996 if (iter->idx < iter->map->map_length)
997 iter->me = iter->map->map[iter->idx];
998 }
999}
1000
1001
1002/**
1003 * Destroy a multiuuidmap iterator.
1004 *
1005 * @param iter the iterator to destroy
1006 */
1007void
1008GNUNET_CONTAINER_multiuuidmap_iterator_destroy (
1009 struct GNUNET_CONTAINER_MultiUuidmapIterator *iter)
1010{
1011 GNUNET_free (iter);
1012}
1013
1014
1015/* end of container_multiuuidmap.c */
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-20 01:42:10 +0000