xref: /illumos-gate/usr/src/lib/lib9p/common/hashtable.h (revision 9b9d39d2a32ff806d2431dbcc50968ef1e6d46b2)
1 /*
2  * Copyright 2016 Jakub Klama <jceel@FreeBSD.org>
3  * All rights reserved
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted providing that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
16  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
18  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
22  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
23  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
24  * POSSIBILITY OF SUCH DAMAGE.
25  *
26  */
27 
28 #ifndef LIB9P_HASHTABLE_H
29 #define LIB9P_HASHTABLE_H
30 
31 #include <pthread.h>
32 #include <sys/queue.h>
33 
34 struct ht {
35 	struct ht_entry * 	ht_entries;
36 	ssize_t 		ht_nentries;
37 	pthread_rwlock_t	ht_rwlock;
38 };
39 
40 struct ht_entry {
41 	TAILQ_HEAD(, ht_item) hte_items;
42 };
43 
44 struct ht_item {
45 	uint32_t		hti_hash;
46 	void *			hti_data;
47 	TAILQ_ENTRY(ht_item)	hti_link;
48 };
49 
50 struct ht_iter {
51 	struct ht *		htit_parent;
52 	struct ht_item *	htit_curr;
53 	struct ht_item *	htit_next;
54 	ssize_t			htit_slot;
55 };
56 
57 #ifdef __clang__
58 #pragma clang diagnostic push
59 #pragma clang diagnostic ignored "-Wthread-safety-analysis"
60 #endif
61 
62 /*
63  * Obtain read-lock on hash table.
64  */
65 static inline int
66 ht_rdlock(struct ht *h)
67 {
68 
69 	return (pthread_rwlock_rdlock(&h->ht_rwlock));
70 }
71 
72 /*
73  * Obtain write-lock on hash table.
74  */
75 static inline int
76 ht_wrlock(struct ht *h)
77 {
78 
79 	return (pthread_rwlock_wrlock(&h->ht_rwlock));
80 }
81 
82 /*
83  * Release lock on hash table.
84  */
85 static inline int
86 ht_unlock(struct ht *h)
87 {
88 
89 	return (pthread_rwlock_unlock(&h->ht_rwlock));
90 }
91 
92 #ifdef __clang__
93 #pragma clang diagnostic pop
94 #endif
95 
96 void ht_init(struct ht *h, ssize_t size);
97 void ht_destroy(struct ht *h);
98 void *ht_find(struct ht *h, uint32_t hash);
99 void *ht_find_locked(struct ht *h, uint32_t hash);
100 int ht_add(struct ht *h, uint32_t hash, void *value);
101 int ht_remove(struct ht *h, uint32_t hash);
102 int ht_remove_locked(struct ht *h, uint32_t hash);
103 int ht_remove_at_iter(struct ht_iter *iter);
104 void ht_iter(struct ht *h, struct ht_iter *iter);
105 void *ht_next(struct ht_iter *iter);
106 
107 #endif  /* LIB9P_HASHTABLE_H */
108