/* * 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 }