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diff --git a/src/util/container_multiuuidmap.c b/src/util/container_multiuuidmap.c
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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() themselves 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 * Value of the entry.
48 */
49 void *value;
50
51 /**
52 * If there is a hash collision, we create a linked list.
53 */
54 struct BigMapEntry *next;
55
56 /**
57 * Key for the entry.
58 */
59 struct GNUNET_Uuid key;
60};
61
62
63/**
64 * An entry in the hash map with just a pointer to the key.
65 */
66struct SmallMapEntry
67{
68 /**
69 * Value of the entry.
70 */
71 void *value;
72
73 /**
74 * If there is a hash collision, we create a linked list.
75 */
76 struct SmallMapEntry *next;
77
78 /**
79 * Key for the entry.
80 */
81 const struct GNUNET_Uuid *key;
82};
83
84
85/**
86 * Entry in the map.
87 */
88union MapEntry
89{
90 /**
91 * Variant used if map entries only contain a pointer to the key.
92 */
93 struct SmallMapEntry *sme;
94
95 /**
96 * Variant used if map entries contain the full key.
97 */
98 struct BigMapEntry *bme;
99};
100
101
102/**
103 * Internal representation of the hash map.
104 */
105struct GNUNET_CONTAINER_MultiUuidmap
106{
107 /**
108 * All of our buckets.
109 */
110 union MapEntry *map;
111
112 /**
113 * Number of entries in the map.
114 */
115 unsigned int size;
116
117 /**
118 * Length of the "map" array.
119 */
120 unsigned int map_length;
121
122 /**
123 * #GNUNET_NO if the map entries are of type 'struct BigMapEntry',
124 * #GNUNET_YES if the map entries are of type 'struct SmallMapEntry'.
125 */
126 int use_small_entries;
127
128 /**
129 * Counts the destructive modifications (grow, remove)
130 * to the map, so that iterators can check if they are still valid.
131 */
132 unsigned int modification_counter;
133
134 /**
135 * Map entries indicating iteration positions currently
136 * in use by #GNUNET_CONTAINER_multihashmap_get_multiple().
137 * Only used up to @e next_cache_off.
138 */
139 union MapEntry next_cache[NEXT_CACHE_SIZE];
140
141 /**
142 * Offset of @e next_cache entries in use, must be smaller
143 * than #NEXT_CACHE_SIZE.
144 */
145 unsigned int next_cache_off;
146};
147
148
149/**
150 * Cursor into a multiuuidmap.
151 * Allows to enumerate elements asynchronously.
152 */
153struct GNUNET_CONTAINER_MultiUuidmapIterator
154{
155 /**
156 * Position in the bucket 'idx'
157 */
158 union MapEntry me;
159
160 /**
161 * Current bucket index.
162 */
163 unsigned int idx;
164
165 /**
166 * Modification counter as observed on the map when the iterator
167 * was created.
168 */
169 unsigned int modification_counter;
170
171 /**
172 * Map that we are iterating over.
173 */
174 const struct GNUNET_CONTAINER_MultiUuidmap *map;
175};
176
177
178/**
179 * Create a multi hash map.
180 *
181 * @param len initial size (map will grow as needed)
182 * @param do_not_copy_keys #GNUNET_NO is always safe and should be used by default;
183 * #GNUNET_YES means that on 'put', the 'key' does not have
184 * to be copied as the destination of the pointer is
185 * guaranteed to be life as long as the value is stored in
186 * the hashmap. This can significantly reduce memory
187 * consumption, but of course is also a recipe for
188 * heap corruption if the assumption is not true. Only
189 * use this if (1) memory use is important in this case and
190 * (2) you have triple-checked that the invariant holds
191 * @return NULL on error
192 */
193struct GNUNET_CONTAINER_MultiUuidmap *
194GNUNET_CONTAINER_multiuuidmap_create (unsigned int len, int do_not_copy_keys)
195{
196 struct GNUNET_CONTAINER_MultiUuidmap *map;
197
198 GNUNET_assert (len > 0);
199 map = GNUNET_new (struct GNUNET_CONTAINER_MultiUuidmap);
200 map->map = GNUNET_malloc_large (len * sizeof(union MapEntry));
201 if (NULL == map->map)
202 {
203 GNUNET_free (map);
204 return NULL;
205 }
206 map->map_length = len;
207 map->use_small_entries = do_not_copy_keys;
208 return map;
209}
210
211
212/**
213 * Destroy a hash map. Will not free any values
214 * stored in the hash map!
215 *
216 * @param map the map
217 */
218void
219GNUNET_CONTAINER_multiuuidmap_destroy (
220 struct GNUNET_CONTAINER_MultiUuidmap *map)
221{
222 GNUNET_assert (0 == map->next_cache_off);
223 for (unsigned int i = 0; i < map->map_length; i++)
224 {
225 union MapEntry me;
226
227 me = map->map[i];
228 if (map->use_small_entries)
229 {
230 struct SmallMapEntry *sme;
231 struct SmallMapEntry *nxt;
232
233 nxt = me.sme;
234 while (NULL != (sme = nxt))
235 {
236 nxt = sme->next;
237 GNUNET_free (sme);
238 }
239 me.sme = NULL;
240 }
241 else
242 {
243 struct BigMapEntry *bme;
244 struct BigMapEntry *nxt;
245
246 nxt = me.bme;
247 while (NULL != (bme = nxt))
248 {
249 nxt = bme->next;
250 GNUNET_free (bme);
251 }
252 me.bme = NULL;
253 }
254 }
255 GNUNET_free (map->map);
256 GNUNET_free (map);
257}
258
259
260/**
261 * Compute the index of the bucket for the given key.
262 *
263 * @param map hash map for which to compute the index
264 * @param key what key should the index be computed for
265 * @return offset into the "map" array of "map"
266 */
267static unsigned int
268idx_of (const struct GNUNET_CONTAINER_MultiUuidmap *map,
269 const struct GNUNET_Uuid *key)
270{
271 unsigned int kx;
272
273 GNUNET_assert (NULL != map);
274 GNUNET_memcpy (&kx, key, sizeof(kx));
275 return kx % map->map_length;
276}
277
278
279/**
280 * Get the number of key-value pairs in the map.
281 *
282 * @param map the map
283 * @return the number of key value pairs
284 */
285unsigned int
286GNUNET_CONTAINER_multiuuidmap_size (
287 const struct GNUNET_CONTAINER_MultiUuidmap *map)
288{
289 return map->size;
290}
291
292
293/**
294 * Given a key find a value in the map matching the key.
295 *
296 * @param map the map
297 * @param key what to look for
298 * @return NULL if no value was found; note that
299 * this is indistinguishable from values that just
300 * happen to be NULL; use "contains" to test for
301 * key-value pairs with value NULL
302 */
303void *
304GNUNET_CONTAINER_multiuuidmap_get (
305 const struct GNUNET_CONTAINER_MultiUuidmap *map,
306 const struct GNUNET_Uuid *key)
307{
308 union MapEntry me;
309
310 me = map->map[idx_of (map, key)];
311 if (map->use_small_entries)
312 {
313 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
314 if (0 == GNUNET_memcmp (key, sme->key))
315 return sme->value;
316 }
317 else
318 {
319 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
320 if (0 == GNUNET_memcmp (key, &bme->key))
321 return bme->value;
322 }
323 return NULL;
324}
325
326
327/**
328 * Iterate over all entries in the map.
329 *
330 * @param map the map
331 * @param it function to call on each entry
332 * @param it_cls extra argument to @a it
333 * @return the number of key value pairs processed,
334 * #GNUNET_SYSERR if it aborted iteration
335 */
336int
337GNUNET_CONTAINER_multiuuidmap_iterate (
338 struct GNUNET_CONTAINER_MultiUuidmap *map,
339 GNUNET_CONTAINER_MultiUuidmapIteratorCallback it,
340 void *it_cls)
341{
342 int count;
343 union MapEntry me;
344 union MapEntry *ce;
345 struct GNUNET_Uuid kc;
346
347 count = 0;
348 GNUNET_assert (NULL != map);
349 ce = &map->next_cache[map->next_cache_off];
350 GNUNET_assert (++map->next_cache_off < NEXT_CACHE_SIZE);
351 for (unsigned int i = 0; i < map->map_length; i++)
352 {
353 me = map->map[i];
354 if (map->use_small_entries)
355 {
356 struct SmallMapEntry *sme;
357
358 ce->sme = me.sme;
359 while (NULL != (sme = ce->sme))
360 {
361 ce->sme = sme->next;
362 if ((NULL != it) && (GNUNET_OK != it (it_cls, sme->key, sme->value)))
363 {
364 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
365 return GNUNET_SYSERR;
366 }
367 count++;
368 }
369 }
370 else
371 {
372 struct BigMapEntry *bme;
373
374 ce->bme = me.bme;
375 while (NULL != (bme = ce->bme))
376 {
377 ce->bme = bme->next;
378 if (NULL != it)
379 {
380 kc = bme->key;
381 if (GNUNET_OK != it (it_cls, &kc, bme->value))
382 {
383 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
384 return GNUNET_SYSERR;
385 }
386 }
387 count++;
388 }
389 }
390 }
391 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
392 return count;
393}
394
395
396/**
397 * We are about to free() the @a bme, make sure it is not in
398 * the list of next values for any iterator in the @a map's next_cache.
399 *
400 * @param map the map to check
401 * @param bme the entry that is about to be free'd
402 */
403static void
404update_next_cache_bme (struct GNUNET_CONTAINER_MultiUuidmap *map,
405 const struct BigMapEntry *bme)
406{
407 for (unsigned int i = 0; i < map->next_cache_off; i++)
408 if (map->next_cache[i].bme == bme)
409 map->next_cache[i].bme = bme->next;
410}
411
412
413/**
414 * We are about to free() the @a sme, make sure it is not in
415 * the list of next values for any iterator in the @a map's next_cache.
416 *
417 * @param map the map to check
418 * @param sme the entry that is about to be free'd
419 */
420static void
421update_next_cache_sme (struct GNUNET_CONTAINER_MultiUuidmap *map,
422 const struct SmallMapEntry *sme)
423{
424 for (unsigned int i = 0; i < map->next_cache_off; i++)
425 if (map->next_cache[i].sme == sme)
426 map->next_cache[i].sme = sme->next;
427}
428
429
430/**
431 * Remove the given key-value pair from the map. Note that if the
432 * key-value pair is in the map multiple times, only one of the pairs
433 * will be removed.
434 *
435 * @param map the map
436 * @param key key of the key-value pair
437 * @param value value of the key-value pair
438 * @return #GNUNET_YES on success, #GNUNET_NO if the key-value pair
439 * is not in the map
440 */
441int
442GNUNET_CONTAINER_multiuuidmap_remove (struct GNUNET_CONTAINER_MultiUuidmap *map,
443 const struct GNUNET_Uuid *key,
444 const void *value)
445{
446 union MapEntry me;
447 unsigned int i;
448
449 map->modification_counter++;
450 i = idx_of (map, key);
451 me = map->map[i];
452 if (map->use_small_entries)
453 {
454 struct SmallMapEntry *p = NULL;
455
456 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
457 {
458 if ((0 == GNUNET_memcmp (key, sme->key)) && (value == sme->value))
459 {
460 if (NULL == p)
461 map->map[i].sme = sme->next;
462 else
463 p->next = sme->next;
464 update_next_cache_sme (map, sme);
465 GNUNET_free (sme);
466 map->size--;
467 return GNUNET_YES;
468 }
469 p = sme;
470 }
471 }
472 else
473 {
474 struct BigMapEntry *p = NULL;
475
476 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
477 {
478 if ((0 == GNUNET_memcmp (key, &bme->key)) && (value == bme->value))
479 {
480 if (NULL == p)
481 map->map[i].bme = bme->next;
482 else
483 p->next = bme->next;
484 update_next_cache_bme (map, bme);
485 GNUNET_free (bme);
486 map->size--;
487 return GNUNET_YES;
488 }
489 p = bme;
490 }
491 }
492 return GNUNET_NO;
493}
494
495
496/**
497 * Remove all entries for the given key from the map.
498 * Note that the values would not be "freed".
499 *
500 * @param map the map
501 * @param key identifies values to be removed
502 * @return number of values removed
503 */
504int
505GNUNET_CONTAINER_multiuuidmap_remove_all (
506 struct GNUNET_CONTAINER_MultiUuidmap *map,
507 const struct GNUNET_Uuid *key)
508{
509 union MapEntry me;
510 unsigned int i;
511 int ret;
512
513 map->modification_counter++;
514
515 ret = 0;
516 i = idx_of (map, key);
517 me = map->map[i];
518 if (map->use_small_entries)
519 {
520 struct SmallMapEntry *sme;
521 struct SmallMapEntry *p;
522
523 p = NULL;
524 sme = me.sme;
525 while (NULL != sme)
526 {
527 if (0 == GNUNET_memcmp (key, sme->key))
528 {
529 if (NULL == p)
530 map->map[i].sme = sme->next;
531 else
532 p->next = sme->next;
533 update_next_cache_sme (map, sme);
534 GNUNET_free (sme);
535 map->size--;
536 if (NULL == p)
537 sme = map->map[i].sme;
538 else
539 sme = p->next;
540 ret++;
541 }
542 else
543 {
544 p = sme;
545 sme = sme->next;
546 }
547 }
548 }
549 else
550 {
551 struct BigMapEntry *bme;
552 struct BigMapEntry *p;
553
554 p = NULL;
555 bme = me.bme;
556 while (NULL != bme)
557 {
558 if (0 == GNUNET_memcmp (key, &bme->key))
559 {
560 if (NULL == p)
561 map->map[i].bme = bme->next;
562 else
563 p->next = bme->next;
564 update_next_cache_bme (map, bme);
565 GNUNET_free (bme);
566 map->size--;
567 if (NULL == p)
568 bme = map->map[i].bme;
569 else
570 bme = p->next;
571 ret++;
572 }
573 else
574 {
575 p = bme;
576 bme = bme->next;
577 }
578 }
579 }
580 return ret;
581}
582
583
584/**
585 * Check if the map contains any value under the given
586 * key (including values that are NULL).
587 *
588 * @param map the map
589 * @param key the key to test if a value exists for it
590 * @return #GNUNET_YES if such a value exists,
591 * #GNUNET_NO if not
592 */
593int
594GNUNET_CONTAINER_multiuuidmap_contains (
595 const struct GNUNET_CONTAINER_MultiUuidmap *map,
596 const struct GNUNET_Uuid *key)
597{
598 union MapEntry me;
599
600 me = map->map[idx_of (map, key)];
601 if (map->use_small_entries)
602 {
603 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
604 if (0 == GNUNET_memcmp (key, sme->key))
605 return GNUNET_YES;
606 }
607 else
608 {
609 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
610 if (0 == GNUNET_memcmp (key, &bme->key))
611 return GNUNET_YES;
612 }
613 return GNUNET_NO;
614}
615
616
617/**
618 * Check if the map contains the given value under the given
619 * key.
620 *
621 * @param map the map
622 * @param key the key to test if a value exists for it
623 * @param value value to test for
624 * @return #GNUNET_YES if such a value exists,
625 * #GNUNET_NO if not
626 */
627int
628GNUNET_CONTAINER_multiuuidmap_contains_value (
629 const struct GNUNET_CONTAINER_MultiUuidmap *map,
630 const struct GNUNET_Uuid *key,
631 const void *value)
632{
633 union MapEntry me;
634
635 me = map->map[idx_of (map, key)];
636 if (map->use_small_entries)
637 {
638 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
639 if ((0 == GNUNET_memcmp (key, sme->key)) && (sme->value == value))
640 return GNUNET_YES;
641 }
642 else
643 {
644 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
645 if ((0 == GNUNET_memcmp (key, &bme->key)) && (bme->value == value))
646 return GNUNET_YES;
647 }
648 return GNUNET_NO;
649}
650
651
652/**
653 * Grow the given map to a more appropriate size.
654 *
655 * @param map the hash map to grow
656 */
657static void
658grow (struct GNUNET_CONTAINER_MultiUuidmap *map)
659{
660 union MapEntry *old_map;
661 union MapEntry *new_map;
662 unsigned int old_len;
663 unsigned int new_len;
664 unsigned int idx;
665
666 old_map = map->map;
667 old_len = map->map_length;
668 new_len = old_len * 2;
669 if (0 == new_len) /* 2^31 * 2 == 0 */
670 new_len = old_len; /* never use 0 */
671 if (new_len == old_len)
672 return; /* nothing changed */
673 new_map = GNUNET_malloc_large (new_len * sizeof(union MapEntry));
674 if (NULL == new_map)
675 return; /* grow not possible */
676 map->modification_counter++;
677 map->map_length = new_len;
678 map->map = new_map;
679 for (unsigned int i = 0; i < old_len; i++)
680 {
681 if (map->use_small_entries)
682 {
683 struct SmallMapEntry *sme;
684
685 while (NULL != (sme = old_map[i].sme))
686 {
687 old_map[i].sme = sme->next;
688 idx = idx_of (map, sme->key);
689 sme->next = new_map[idx].sme;
690 new_map[idx].sme = sme;
691 }
692 }
693 else
694 {
695 struct BigMapEntry *bme;
696
697 while (NULL != (bme = old_map[i].bme))
698 {
699 old_map[i].bme = bme->next;
700 idx = idx_of (map, &bme->key);
701 bme->next = new_map[idx].bme;
702 new_map[idx].bme = bme;
703 }
704 }
705 }
706 GNUNET_free (old_map);
707}
708
709
710/**
711 * Store a key-value pair in the map.
712 *
713 * @param map the map
714 * @param key key to use
715 * @param value value to use
716 * @param opt options for put
717 * @return #GNUNET_OK on success,
718 * #GNUNET_NO if a value was replaced (with REPLACE)
719 * #GNUNET_SYSERR if #GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY was the option and the
720 * value already exists
721 */
722int
723GNUNET_CONTAINER_multiuuidmap_put (struct GNUNET_CONTAINER_MultiUuidmap *map,
724 const struct GNUNET_Uuid *key,
725 void *value,
726 enum GNUNET_CONTAINER_MultiHashMapOption opt)
727{
728 union MapEntry me;
729 unsigned int i;
730
731 i = idx_of (map, key);
732 if ((opt != GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE) &&
733 (opt != GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST))
734 {
735 me = map->map[i];
736 if (map->use_small_entries)
737 {
738 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
739 if (0 == GNUNET_memcmp (key, sme->key))
740 {
741 if (opt == GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)
742 return GNUNET_SYSERR;
743 sme->value = value;
744 return GNUNET_NO;
745 }
746 }
747 else
748 {
749 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
750 if (0 == GNUNET_memcmp (key, &bme->key))
751 {
752 if (opt == GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)
753 return GNUNET_SYSERR;
754 bme->value = value;
755 return GNUNET_NO;
756 }
757 }
758 }
759 if (map->size / 3 >= map->map_length / 4)
760 {
761 grow (map);
762 i = idx_of (map, key);
763 }
764 if (map->use_small_entries)
765 {
766 struct SmallMapEntry *sme;
767
768 sme = GNUNET_new (struct SmallMapEntry);
769 sme->key = key;
770 sme->value = value;
771 sme->next = map->map[i].sme;
772 map->map[i].sme = sme;
773 }
774 else
775 {
776 struct BigMapEntry *bme;
777
778 bme = GNUNET_new (struct BigMapEntry);
779 bme->key = *key;
780 bme->value = value;
781 bme->next = map->map[i].bme;
782 map->map[i].bme = bme;
783 }
784 map->size++;
785 return GNUNET_OK;
786}
787
788
789/**
790 * Iterate over all entries in the map that match a particular key.
791 *
792 * @param map the map
793 * @param key key that the entries must correspond to
794 * @param it function to call on each entry
795 * @param it_cls extra argument to @a it
796 * @return the number of key value pairs processed,
797 * #GNUNET_SYSERR if it aborted iteration
798 */
799int
800GNUNET_CONTAINER_multiuuidmap_get_multiple (
801 struct GNUNET_CONTAINER_MultiUuidmap *map,
802 const struct GNUNET_Uuid *key,
803 GNUNET_CONTAINER_MultiUuidmapIteratorCallback it,
804 void *it_cls)
805{
806 int count;
807 union MapEntry me;
808 union MapEntry *ce;
809
810 ce = &map->next_cache[map->next_cache_off];
811 GNUNET_assert (++map->next_cache_off < NEXT_CACHE_SIZE);
812 count = 0;
813 me = map->map[idx_of (map, key)];
814 if (map->use_small_entries)
815 {
816 struct SmallMapEntry *sme;
817
818 ce->sme = me.sme;
819 while (NULL != (sme = ce->sme))
820 {
821 ce->sme = sme->next;
822 if (0 != GNUNET_memcmp (key, sme->key))
823 continue;
824 if ((NULL != it) && (GNUNET_OK != it (it_cls, key, sme->value)))
825 {
826 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
827 return GNUNET_SYSERR;
828 }
829 count++;
830 }
831 }
832 else
833 {
834 struct BigMapEntry *bme;
835
836 ce->bme = me.bme;
837 while (NULL != (bme = ce->bme))
838 {
839 ce->bme = bme->next;
840 if (0 != GNUNET_memcmp (key, &bme->key))
841 continue;
842 if ((NULL != it) && (GNUNET_OK != it (it_cls, key, bme->value)))
843 {
844 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
845 return GNUNET_SYSERR;
846 }
847 count++;
848 }
849 }
850 GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
851 return count;
852}
853
854
855/**
856 * @ingroup hashmap
857 * Call @a it on a random value from the map, or not at all
858 * if the map is empty. Note that this function has linear
859 * complexity (in the size of the map).
860 *
861 * @param map the map
862 * @param it function to call on a random entry
863 * @param it_cls extra argument to @a it
864 * @return the number of key value pairs processed, zero or one.
865 */
866unsigned int
867GNUNET_CONTAINER_multiuuidmap_get_random (
868 const struct GNUNET_CONTAINER_MultiUuidmap *map,
869 GNUNET_CONTAINER_MultiUuidmapIteratorCallback it,
870 void *it_cls)
871{
872 unsigned int off;
873 union MapEntry me;
874
875 if (0 == map->size)
876 return 0;
877 if (NULL == it)
878 return 1;
879 off = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, map->size);
880 for (unsigned int idx = 0; idx < map->map_length; idx++)
881 {
882 me = map->map[idx];
883 if (map->use_small_entries)
884 {
885 for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
886 {
887 if (0 == off)
888 {
889 if (GNUNET_OK != it (it_cls, sme->key, sme->value))
890 return GNUNET_SYSERR;
891 return 1;
892 }
893 off--;
894 }
895 }
896 else
897 {
898 for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
899 {
900 if (0 == off)
901 {
902 if (GNUNET_OK != it (it_cls, &bme->key, bme->value))
903 return GNUNET_SYSERR;
904 return 1;
905 }
906 off--;
907 }
908 }
909 }
910 GNUNET_break (0);
911 return GNUNET_SYSERR;
912}
913
914
915/**
916 * Create an iterator for a multiuuidmap.
917 * The iterator can be used to retrieve all the elements in the multiuuidmap
918 * one by one, without having to handle all elements at once (in contrast to
919 * #GNUNET_CONTAINER_multiuuidmap_iterate). Note that the iterator can not be
920 * used anymore if elements have been removed from 'map' after the creation of
921 * the iterator, or 'map' has been destroyed. Adding elements to 'map' may
922 * result in skipped or repeated elements.
923 *
924 * @param map the map to create an iterator for
925 * @return an iterator over the given multiuuidmap 'map'
926 */
927struct GNUNET_CONTAINER_MultiUuidmapIterator *
928GNUNET_CONTAINER_multiuuidmap_iterator_create (
929 const struct GNUNET_CONTAINER_MultiUuidmap *map)
930{
931 struct GNUNET_CONTAINER_MultiUuidmapIterator *iter;
932
933 iter = GNUNET_new (struct GNUNET_CONTAINER_MultiUuidmapIterator);
934 iter->map = map;
935 iter->modification_counter = map->modification_counter;
936 iter->me = map->map[0];
937 return iter;
938}
939
940
941/**
942 * Retrieve the next element from the hash map at the iterator's position.
943 * If there are no elements left, GNUNET_NO is returned, and 'key' and 'value'
944 * are not modified.
945 * This operation is only allowed if no elements have been removed from the
946 * multiuuidmap since the creation of 'iter', and the map has not been destroyed.
947 * Adding elements may result in repeating or skipping elements.
948 *
949 * @param iter the iterator to get the next element from
950 * @param key pointer to store the key in, can be NULL
951 * @param value pointer to store the value in, can be NULL
952 * @return #GNUNET_YES we returned an element,
953 * #GNUNET_NO if we are out of elements
954 */
955int
956GNUNET_CONTAINER_multiuuidmap_iterator_next (
957 struct GNUNET_CONTAINER_MultiUuidmapIterator *iter,
958 struct GNUNET_Uuid *key,
959 const void **value)
960{
961 /* make sure the map has not been modified */
962 GNUNET_assert (iter->modification_counter == iter->map->modification_counter);
963
964 /* look for the next entry, skipping empty buckets */
965 while (1)
966 {
967 if (iter->idx >= iter->map->map_length)
968 return GNUNET_NO;
969 if (GNUNET_YES == iter->map->use_small_entries)
970 {
971 if (NULL != iter->me.sme)
972 {
973 if (NULL != key)
974 *key = *iter->me.sme->key;
975 if (NULL != value)
976 *value = iter->me.sme->value;
977 iter->me.sme = iter->me.sme->next;
978 return GNUNET_YES;
979 }
980 }
981 else
982 {
983 if (NULL != iter->me.bme)
984 {
985 if (NULL != key)
986 *key = iter->me.bme->key;
987 if (NULL != value)
988 *value = iter->me.bme->value;
989 iter->me.bme = iter->me.bme->next;
990 return GNUNET_YES;
991 }
992 }
993 iter->idx += 1;
994 if (iter->idx < iter->map->map_length)
995 iter->me = iter->map->map[iter->idx];
996 }
997}
998
999
1000/**
1001 * Destroy a multiuuidmap iterator.
1002 *
1003 * @param iter the iterator to destroy
1004 */
1005void
1006GNUNET_CONTAINER_multiuuidmap_iterator_destroy (
1007 struct GNUNET_CONTAINER_MultiUuidmapIterator *iter)
1008{
1009 GNUNET_free (iter);
1010}
1011
1012
1013/* end of container_multiuuidmap.c */
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-18 14:42:06 +0000