1/*	$NetBSD: hash.c,v 1.1.1.1 2011/04/13 18:14:41 elric Exp $	*/
2
3/*
4 * Copyright (c) 1997 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36/*
37 * Hash table functions
38 */
39
40#include "gen_locl.h"
41
42__RCSID("$NetBSD: hash.c,v 1.1.1.1 2011/04/13 18:14:41 elric Exp $");
43
44static Hashentry *_search(Hashtab * htab,	/* The hash table */
45			  void *ptr);	/* And key */
46
47Hashtab *
48hashtabnew(int sz,
49	   int (*cmp) (void *, void *),
50	   unsigned (*hash) (void *))
51{
52    Hashtab *htab;
53    int i;
54
55    assert(sz > 0);
56
57    htab = (Hashtab *) malloc(sizeof(Hashtab) + (sz - 1) * sizeof(Hashentry *));
58    if (htab == NULL)
59	return NULL;
60
61    for (i = 0; i < sz; ++i)
62	htab->tab[i] = NULL;
63
64    htab->cmp = cmp;
65    htab->hash = hash;
66    htab->sz = sz;
67    return htab;
68}
69
70/* Intern search function */
71
72static Hashentry *
73_search(Hashtab * htab, void *ptr)
74{
75    Hashentry *hptr;
76
77    assert(htab && ptr);
78
79    for (hptr = htab->tab[(*htab->hash) (ptr) % htab->sz];
80	 hptr;
81	 hptr = hptr->next)
82	if ((*htab->cmp) (ptr, hptr->ptr) == 0)
83	    break;
84    return hptr;
85}
86
87/* Search for element in hash table */
88
89void *
90hashtabsearch(Hashtab * htab, void *ptr)
91{
92    Hashentry *tmp;
93
94    tmp = _search(htab, ptr);
95    return tmp ? tmp->ptr : tmp;
96}
97
98/* add element to hash table */
99/* if already there, set new value */
100/* !NULL if succesful */
101
102void *
103hashtabadd(Hashtab * htab, void *ptr)
104{
105    Hashentry *h = _search(htab, ptr);
106    Hashentry **tabptr;
107
108    assert(htab && ptr);
109
110    if (h)
111	free((void *) h->ptr);
112    else {
113	h = (Hashentry *) malloc(sizeof(Hashentry));
114	if (h == NULL) {
115	    return NULL;
116	}
117	tabptr = &htab->tab[(*htab->hash) (ptr) % htab->sz];
118	h->next = *tabptr;
119	*tabptr = h;
120	h->prev = tabptr;
121	if (h->next)
122	    h->next->prev = &h->next;
123    }
124    h->ptr = ptr;
125    return h;
126}
127
128/* delete element with key key. Iff freep, free Hashentry->ptr */
129
130int
131_hashtabdel(Hashtab * htab, void *ptr, int freep)
132{
133    Hashentry *h;
134
135    assert(htab && ptr);
136
137    h = _search(htab, ptr);
138    if (h) {
139	if (freep)
140	    free(h->ptr);
141	if ((*(h->prev) = h->next))
142	    h->next->prev = h->prev;
143	free(h);
144	return 0;
145    } else
146	return -1;
147}
148
149/* Do something for each element */
150
151void
152hashtabforeach(Hashtab * htab, int (*func) (void *ptr, void *arg),
153	       void *arg)
154{
155    Hashentry **h, *g;
156
157    assert(htab);
158
159    for (h = htab->tab; h < &htab->tab[htab->sz]; ++h)
160	for (g = *h; g; g = g->next)
161	    if ((*func) (g->ptr, arg))
162		return;
163}
164
165/* standard hash-functions for strings */
166
167unsigned
168hashadd(const char *s)
169{				/* Standard hash function */
170    unsigned i;
171
172    assert(s);
173
174    for (i = 0; *s; ++s)
175	i += *s;
176    return i;
177}
178
179unsigned
180hashcaseadd(const char *s)
181{				/* Standard hash function */
182    unsigned i;
183
184    assert(s);
185
186    for (i = 0; *s; ++s)
187	i += toupper((unsigned char)*s);
188    return i;
189}
190
191#define TWELVE (sizeof(unsigned))
192#define SEVENTYFIVE (6*sizeof(unsigned))
193#define HIGH_BITS (~((unsigned)(~0) >> TWELVE))
194
195unsigned
196hashjpw(const char *ss)
197{				/* another hash function */
198    unsigned h = 0;
199    unsigned g;
200    const unsigned char *s = (const unsigned char *)ss;
201
202    for (; *s; ++s) {
203	h = (h << TWELVE) + *s;
204	if ((g = h & HIGH_BITS))
205	    h = (h ^ (g >> SEVENTYFIVE)) & ~HIGH_BITS;
206    }
207    return h;
208}
209