1 /* $NetBSD: hash.c,v 1.1.1.2 2014/04/24 12:45:28 pettai 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");
43
44 static Hashentry *_search(Hashtab * htab, /* The hash table */
45 void *ptr); /* And key */
46
47 Hashtab *
hashtabnew(int sz,int (* cmp)(void *,void *),unsigned (* hash)(void *))48 hashtabnew(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
72 static Hashentry *
_search(Hashtab * htab,void * ptr)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
89 void *
hashtabsearch(Hashtab * htab,void * ptr)90 hashtabsearch(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
102 void *
hashtabadd(Hashtab * htab,void * ptr)103 hashtabadd(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
130 int
_hashtabdel(Hashtab * htab,void * ptr,int freep)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
151 void
hashtabforeach(Hashtab * htab,int (* func)(void * ptr,void * arg),void * arg)152 hashtabforeach(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
167 unsigned
hashadd(const char * s)168 hashadd(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
179 unsigned
hashcaseadd(const char * s)180 hashcaseadd(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
195 unsigned
hashjpw(const char * ss)196 hashjpw(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