1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26#include <string.h>
27#include <stdlib.h>
28#include <sys/nsctl/nsc_hash.h>
29
30#define	HASH_PRIME 2039
31
32static int calc_hash(const char *);
33
34hash_node_t **
35nsc_create_hash()
36{
37	hash_node_t **hash;
38
39	hash = (hash_node_t **)calloc(HASH_PRIME, sizeof (hash_node_t *));
40	return (hash);
41}
42
43int
44nsc_insert_node(hash_node_t **hash, void *data, const char *key)
45{
46	int index;
47	hash_node_t *node;
48
49	node = (hash_node_t *)malloc(sizeof (hash_node_t));
50	if (!node) {
51		return (-1);
52	}
53	node->key = strdup(key);
54	node->data = data;
55
56	/*
57	 * possible enhancement would be to search
58	 * in this index for a duplicate
59	 */
60	index = calc_hash(key);
61	node->next = hash[ index ];
62	hash[ index ] = node;
63
64	return (0);
65}
66
67/*
68 * lookup
69 *
70 * Description:
71 *	Searches the hash to find a node.
72 *
73 * Return values:
74 *	0 if not found.
75 *	pointer to node if found.
76 */
77void *
78nsc_lookup(hash_node_t **hash, const char *key)
79{
80	int index;
81	hash_node_t *node;
82
83	index = calc_hash(key);
84	node = hash[ index ];
85	while (node) {
86		if (strcmp(node->key, key) == 0)
87			return (node->data);
88		node = node->next;
89	}
90	return (0);
91}
92
93void *
94nsc_remove_node(hash_node_t **hash, char *key)
95{
96	int index;
97	hash_node_t *node, *prev;
98	void *retval;
99
100	index = calc_hash(key);
101	if (!hash[ index ]) {
102		return (0);
103	}
104
105	if (strcmp(hash[ index ]->key, key) == 0) {
106		node = hash[ index ];
107		retval = node->data;
108		hash[ index ] = hash[ index ]->next;
109		free(node->key);
110		free(node);
111		return (retval);
112	}
113	prev = hash[ index ];
114	node = prev->next;
115	while (node && (strcmp(node->key, key) != 0)) {
116		prev = node;
117		node = node->next;
118	}
119
120	/* did we find it? */
121	if (node) {
122		prev->next = node->next;
123		retval = node->data;
124		free(node->key);
125		free(node);
126		return (retval);
127	}
128	return (0);
129}
130
131void
132nsc_remove_all(hash_node_t **hash, void (*callback)(void *))
133{
134	int i;
135	hash_node_t *p, *next;
136
137	for (i = 0; i < HASH_PRIME; i++) {
138		p = hash[ i ];
139		while (p) {
140			next = p->next;
141			if (callback) {
142				callback(p->data);
143			}
144			free(p->key);
145			free(p);
146			p = next;
147		}
148	}
149	free(hash);
150}
151
152/* ---------------------------------------------------------------------- */
153
154/*
155 * Basic rotating hash, as per Knuth.
156 */
157static int
158calc_hash(const char *key)
159{
160	unsigned int hash, i;
161	int len = strlen(key);
162	for (hash = len, i = 0; i < len; i++) {
163		hash = (hash << 5) ^ (hash >> 27) ^ key[ i ];
164	}
165	return (hash % HASH_PRIME);
166}
167