mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-25 11:37:56 +00:00
123 lines
3.5 KiB
C
123 lines
3.5 KiB
C
/* $OpenBSD: hash.c,v 1.9 2004/05/10 15:30:47 deraadt Exp $ */
|
|
|
|
/* Routines for manipulating hash tables... */
|
|
|
|
/*
|
|
* Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of The Internet Software Consortium nor the names
|
|
* of its contributors may be used to endorse or promote products derived
|
|
* from this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
|
|
* CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
|
|
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
|
* DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
|
|
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
|
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
|
|
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
|
|
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
|
|
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* This software has been written for the Internet Software Consortium
|
|
* by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
|
|
* Enterprises. To learn more about the Internet Software Consortium,
|
|
* see ``http://www.vix.com/isc''. To learn more about Vixie
|
|
* Enterprises, see ``http://www.vix.com''.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include "dhcpd.h"
|
|
|
|
static int do_hash(unsigned char *, int, int);
|
|
|
|
struct hash_table *
|
|
new_hash(void)
|
|
{
|
|
struct hash_table *rv = new_hash_table(DEFAULT_HASH_SIZE);
|
|
|
|
if (!rv)
|
|
return (rv);
|
|
memset(&rv->buckets[0], 0,
|
|
DEFAULT_HASH_SIZE * sizeof(struct hash_bucket *));
|
|
return (rv);
|
|
}
|
|
|
|
static int
|
|
do_hash(unsigned char *name, int len, int size)
|
|
{
|
|
unsigned char *s = name;
|
|
int accum = 0, i = len;
|
|
|
|
while (i--) {
|
|
/* Add the character in... */
|
|
accum += *s++;
|
|
/* Add carry back in... */
|
|
while (accum > 255)
|
|
accum = (accum & 255) + (accum >> 8);
|
|
}
|
|
return (accum % size);
|
|
}
|
|
|
|
void add_hash(struct hash_table *table, unsigned char *name, int len,
|
|
unsigned char *pointer)
|
|
{
|
|
struct hash_bucket *bp;
|
|
int hashno;
|
|
|
|
if (!table)
|
|
return;
|
|
if (!len)
|
|
len = strlen((char *)name);
|
|
|
|
hashno = do_hash(name, len, table->hash_count);
|
|
bp = new_hash_bucket();
|
|
|
|
if (!bp) {
|
|
warning("Can't add %s to hash table.", name);
|
|
return;
|
|
}
|
|
bp->name = name;
|
|
bp->value = pointer;
|
|
bp->next = table->buckets[hashno];
|
|
bp->len = len;
|
|
table->buckets[hashno] = bp;
|
|
}
|
|
|
|
unsigned char *
|
|
hash_lookup(struct hash_table *table, unsigned char *name, int len)
|
|
{
|
|
struct hash_bucket *bp;
|
|
int hashno;
|
|
|
|
if (!table)
|
|
return (NULL);
|
|
|
|
if (!len)
|
|
len = strlen((char *)name);
|
|
|
|
hashno = do_hash(name, len, table->hash_count);
|
|
|
|
for (bp = table->buckets[hashno]; bp; bp = bp->next)
|
|
if (len == bp->len && !memcmp(bp->name, name, len))
|
|
return (bp->value);
|
|
|
|
return (NULL);
|
|
}
|