uuid_hash.c revision 139601
1106184Smarcel/*- 2139601Smarcel * Copyright (c) 2002,2005 Marcel Moolenaar 3106184Smarcel * Copyright (c) 2002 Hiten Mahesh Pandya 4106184Smarcel * All rights reserved. 5106184Smarcel * 6106184Smarcel * Redistribution and use in source and binary forms, with or without 7106184Smarcel * modification, are permitted provided that the following conditions 8106184Smarcel * are met: 9106184Smarcel * 1. Redistributions of source code must retain the above copyright 10106184Smarcel * notice, this list of conditions and the following disclaimer. 11106184Smarcel * 2. Redistributions in binary form must reproduce the above copyright 12106184Smarcel * notice, this list of conditions and the following disclaimer in the 13106184Smarcel * documentation and/or other materials provided with the distribution. 14106184Smarcel * 15106184Smarcel * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16106184Smarcel * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17106184Smarcel * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18106184Smarcel * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19106184Smarcel * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20106184Smarcel * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21106184Smarcel * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22106184Smarcel * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23106184Smarcel * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24106184Smarcel * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25106184Smarcel * SUCH DAMAGE. 26106184Smarcel * 27106184Smarcel * $FreeBSD: head/lib/libc/uuid/uuid_hash.c 139601 2005-01-03 02:56:15Z marcel $ 28106184Smarcel */ 29106184Smarcel 30106184Smarcel#include <uuid.h> 31106184Smarcel 32106184Smarcel/* 33106184Smarcel * uuid_hash() - generate a hash value. 34106184Smarcel * See also: 35106184Smarcel * http://www.opengroup.org/onlinepubs/009629399/uuid_hash.htm 36106184Smarcel */ 37106184Smarceluint16_t 38139601Smarceluuid_hash(const uuid_t *u, uint32_t *status) 39106184Smarcel{ 40106184Smarcel 41106184Smarcel if (status) 42106184Smarcel *status = uuid_s_ok; 43106184Smarcel 44106184Smarcel /* 45106184Smarcel * Use the most frequently changing bits in the UUID as the hash 46106184Smarcel * value. This should yield a good enough distribution... 47106184Smarcel */ 48106184Smarcel return ((u) ? u->time_low & 0xffff : 0); 49106184Smarcel} 50