1 /* $OpenBSD: hash.c,v 1.9 2004/05/10 15:30:47 deraadt Exp $ */
3 /* Routines for manipulating hash tables... */
6 * SPDX-License-Identifier: BSD-3-Clause
8 * Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of The Internet Software Consortium nor the names
21 * of its contributors may be used to endorse or promote products derived
22 * from this software without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
25 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
26 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
27 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
28 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
29 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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33 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
34 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
35 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * This software has been written for the Internet Software Consortium
39 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
40 * Enterprises. To learn more about the Internet Software Consortium,
41 * see ``http://www.vix.com/isc''. To learn more about Vixie
42 * Enterprises, see ``http://www.vix.com''.
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD$");
50 static int do_hash(const unsigned char *, int, int);
55 struct hash_table *rv = new_hash_table(DEFAULT_HASH_SIZE);
59 memset(&rv->buckets[0], 0,
60 DEFAULT_HASH_SIZE * sizeof(struct hash_bucket *));
65 do_hash(const unsigned char *name, int len, int size)
67 const unsigned char *s = name;
68 int accum = 0, i = len;
71 /* Add the character in... */
73 /* Add carry back in... */
75 accum = (accum & 255) + (accum >> 8);
77 return (accum % size);
80 void add_hash(struct hash_table *table, const unsigned char *name, int len,
81 unsigned char *pointer)
83 struct hash_bucket *bp;
89 len = strlen((const char *)name);
91 hashno = do_hash(name, len, table->hash_count);
92 bp = new_hash_bucket();
95 warning("Can't add %s to hash table.", name);
100 bp->next = table->buckets[hashno];
102 table->buckets[hashno] = bp;
106 hash_lookup(struct hash_table *table, unsigned char *name, int len)
108 struct hash_bucket *bp;
115 len = strlen((char *)name);
117 hashno = do_hash(name, len, table->hash_count);
119 for (bp = table->buckets[hashno]; bp; bp = bp->next)
120 if (len == bp->len && !memcmp(bp->name, name, len))