rculfhash: Check that init size is power of 2
[urcu.git] / urcu / rculfhash.h
CommitLineData
a42cc659
MD
1#ifndef _URCU_RCULFHASH_H
2#define _URCU_RCULFHASH_H
ab7d5fc6 3
f0c29ed7
MD
4/*
5 * urcu/rculfhash.h
6 *
7 * Userspace RCU library - Lock-Free RCU Hash Table
8 *
9 * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 *
11 * This library is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public
13 * License as published by the Free Software Foundation; either
14 * version 2.1 of the License, or (at your option) any later version.
15 *
16 * This library is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this library; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 */
25
674f7a69 26#include <stdint.h>
abc490a1
MD
27#include <urcu-call-rcu.h>
28
01389791
MD
29#ifdef __cplusplus
30extern "C" {
31#endif
32
7f61a77f 33/*
14044b37 34 * struct cds_lfht_node and struct _cds_lfht_node should be aligned on
7f61a77f
MD
35 * 4-bytes boundaries because the two lower bits are used as flags.
36 */
37
14044b37
MD
38struct _cds_lfht_node {
39 struct cds_lfht_node *next; /* ptr | DUMMY_FLAG | REMOVED_FLAG */
abc490a1 40 unsigned long reverse_hash;
cc4fcb10
MD
41};
42
14044b37 43struct cds_lfht_node {
cc4fcb10 44 /* cache-hot for iteration */
14044b37 45 struct _cds_lfht_node p; /* needs to be first field */
9b35f1e4
MD
46 void *key;
47 unsigned int key_len;
9b35f1e4 48 /* cache-cold for iteration */
abc490a1
MD
49 struct rcu_head head;
50};
51
14044b37 52struct cds_lfht;
ab7d5fc6 53
5e28c532
MD
54/*
55 * Caution !
abc490a1 56 * Ensure reader and writer threads are registered as urcu readers.
5e28c532
MD
57 */
58
14044b37
MD
59typedef unsigned long (*cds_lfht_hash_fct)(void *key, size_t length,
60 unsigned long seed);
61typedef unsigned long (*cds_lfht_compare_fct)(void *key1, size_t key1_len,
62 void *key2, size_t key2_len);
abc490a1 63
f0c29ed7 64/*
14044b37 65 * cds_lfht_node_init - initialize a hash table node
f0c29ed7 66 */
abc490a1 67static inline
14044b37
MD
68void cds_lfht_node_init(struct cds_lfht_node *node, void *key,
69 size_t key_len)
abc490a1
MD
70{
71 node->key = key;
732ad076 72 node->key_len = key_len;
abc490a1 73}
674f7a69
MD
74
75/*
14044b37 76 * cds_lfht_new - allocate a hash table.
f0c29ed7 77 *
674f7a69
MD
78 * init_size must be power of two.
79 */
14044b37
MD
80struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct,
81 cds_lfht_compare_fct compare_fct,
82 unsigned long hash_seed,
83 unsigned long init_size,
84 void (*cds_lfht_call_rcu)(struct rcu_head *head,
abc490a1 85 void (*func)(struct rcu_head *head)));
ab7d5fc6 86
f0c29ed7 87/*
14044b37 88 * cds_lfht_destroy - destroy a hash table.
f0c29ed7 89 */
14044b37 90int cds_lfht_destroy(struct cds_lfht *ht);
f0c29ed7
MD
91
92/*
14044b37 93 * cds_lfht_count_nodes - count the number of nodes in the hash table.
f0c29ed7
MD
94 *
95 * Call with rcu_read_lock held.
96 */
14044b37
MD
97void cds_lfht_count_nodes(struct cds_lfht *ht,
98 unsigned long *count,
99 unsigned long *removed);
ab7d5fc6 100
f0c29ed7 101/*
14044b37 102 * cds_lfht_lookup - lookup a node by key.
f0c29ed7
MD
103 *
104 * Returns NULL if not found.
105 * Call with rcu_read_lock held.
106 */
14044b37 107struct cds_lfht_node *cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len);
ab7d5fc6 108
f0c29ed7 109/*
14044b37 110 * cds_lfht_next - get the next item with same key (after a lookup).
f0c29ed7
MD
111 *
112 * Returns NULL if no following node exists with same key.
14044b37
MD
113 * RCU read-side lock must be held across cds_lfht_lookup and cds_lfht_next calls, and also
114 * between cds_lfht_next calls using the node returned by a previous cds_lfht_next.
f0c29ed7
MD
115 * Call with rcu_read_lock held.
116 */
14044b37 117struct cds_lfht_node *cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_node *node);
ab7d5fc6 118
18117871 119/*
14044b37 120 * cds_lfht_add - add a node to the hash table.
f0c29ed7 121 *
18117871 122 * Call with rcu_read_lock held.
f0c29ed7 123 */
14044b37 124void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node);
f0c29ed7
MD
125
126/*
14044b37 127 * cds_lfht_add_unique - add a node to hash table, if key is not present.
f0c29ed7 128 *
18117871 129 * Returns the node added upon success.
14044b37 130 * Returns the unique node already present upon failure. If cds_lfht_add_unique fails,
18117871 131 * the node passed as parameter should be freed by the caller.
f0c29ed7 132 * Call with rcu_read_lock held.
18117871 133 */
14044b37 134struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, struct cds_lfht_node *node);
3eca1b8c 135
f0c29ed7 136/*
14044b37 137 * cds_lfht_remove - remove node from hash table.
f0c29ed7 138 *
14044b37 139 * Node can be looked up with cds_lfht_lookup. RCU read-side lock must be held between
f0c29ed7
MD
140 * lookup and removal.
141 * Call with rcu_read_lock held.
142 */
14044b37 143int cds_lfht_remove(struct cds_lfht *ht, struct cds_lfht_node *node);
ab7d5fc6 144
f0c29ed7 145/*
14044b37 146 * cds_lfht_resize - Force a hash table resize
f0c29ed7
MD
147 * @growth: growth order (current size is multiplied by 2^growth)
148 *
149 * Currently, only expand operation is supported (growth >= 0).
150 */
14044b37 151void cds_lfht_resize(struct cds_lfht *ht, int growth);
464a1ec9 152
01389791
MD
153#ifdef __cplusplus
154}
155#endif
156
a42cc659 157#endif /* _URCU_RCULFHASH_H */
This page took 0.043314 seconds and 4 git commands to generate.