workbench/network/stacks/AROSTCP/bsdsocket/kern/kern_subr.c

   1 /*
   2  * Copyright (c) 1982, 1986, 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  * Copyright (c) 2006 Pavel Fedin
   5  * (c) UNIX System Laboratories, Inc.
   6  * All or some portions of this file are derived from material licensed
   7  * to the University of California by American Telephone and Telegraph
   8  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   9  * the permission of UNIX System Laboratories, Inc.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgement:
  21  *      This product includes software developed by the University of
  22  *      California, Berkeley and its contributors.
  23  * 4. Neither the name of the University nor the names of its contributors
  24  *    may be used to endorse or promote products derived from this software
  25  *    without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  37  * SUCH DAMAGE.
  38  *
  39  *      @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
  40  * $Id$
  41  */
  42
  43 #include <sys/param.h>
  44 #include <sys/systm.h>
  45 #include <sys/malloc.h>
  46 #include <sys/queue.h>
  47
  48 #define NPRIMES 27
  49 static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039,
  50                         2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
  51                         7159, 7673, 8191, 12281, 16381, 24571, 32749 };
  52
  53 /*
  54  * General routine to allocate a prime number sized hash table.
  55  */
  56 void *
  57 phashinit(elements, type, nentries)
  58         int elements, type;
  59         u_long *nentries;
  60 {
  61         long hashsize;
  62         LIST_HEAD(generic, generic) *hashtbl;
  63         int i;
  64
  65         if (elements <= 0)
  66                 panic("phashinit: bad elements");
  67         for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
  68                 i++;
  69                 if (i == NPRIMES)
  70                         break;
  71                 hashsize = primes[i];
  72         }
  73         hashsize = primes[i - 1];
  74         hashtbl = bsd_malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
  75         for (i = 0; i < hashsize; i++)
  76                 LIST_INIT(&hashtbl[i]);
  77         *nentries = hashsize;
  78         return (hashtbl);
  79 }