/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
#pragma ident "%Z%%M% %I% %E% SMI"
#include <stdlib.h>
#include "hash.h"
#define LOCHWIDTH 3
#define HICHWIDTH 3
#define CHARWIDTH (LOCHWIDTH+HICHWIDTH)
#define LOCHMASK ((1<<LOCHWIDTH)-1)
/*
* if HASHWIDTH + CHARWIDTH < bitsizeof(long)
* one could make LOCHWIDTH=6 and HICHWIDTH=0
* and simplify accordingly; the hanky-panky
* is to avoid overflow in long multiplication
*/
#define NC 30
static long hashsize = HASHSIZE;
static long pow2[NC*2];
static signed char hashtab[] = {
-1, -1, -1, -1, -1, -1, 0, 31, /* &' */
-1, -1, -1, -1, 68, -1, 65, -1,
2, 25, 20, 35, 54, 61, 40, 39, /* 0-7 */
42, 33, 64, 67, -1, -1, -1, 66,
-1, 60, 43, 30, 5, 16, 47, 18, /* A-G */
41, 36, 51, 6, 13, 56, 55, 58,
49, 12, 59, 46, 21, 32, 63, 34,
57, 52, 3, -1, -1, -1, -1, -1,
-1, 22, 29, 8, 7, 10, 1, 28, /* a-g */
11, 62, 37, 48, 15, 50, 9, 4,
19, 38, 45, 24, 23, 26, 17, 44,
27, 14, 53, -1, -1, -1, -1, -1
};
unsigned long
hash(char *s)
{
int c;
long *lp;
unsigned long h = 0;
for (lp = pow2; (c = *s++) != 0; ) {
c = hashtab[c-' '];
h += (c&LOCHMASK) * *lp++;
h += (c>>LOCHWIDTH) * *lp++;
h %= hashsize;
}
return (h);
}
void
hashinit(void)
{
#if ((1L << (HASHWIDTH+LOCHWIDTH) == 0) || (1L << (HASHWIDTH+HICHWIDTH) == 0))
abort(); /* overflow is imminent */
#else
int i;
pow2[0] = 1L<<(HASHWIDTH-CHARWIDTH-2);
for (i = 0; i < 2*NC-3; i += 2) {
pow2[i+1] = (pow2[i]<<LOCHWIDTH) % hashsize;
pow2[i+2] = (pow2[i+1]<<HICHWIDTH) % hashsize;
}
#endif
}