1 1.5 riastrad /* $NetBSD: hash.h,v 1.5 2021/12/19 12:02:40 riastradh Exp $ */ 2 1.2 riastrad 3 1.2 riastrad /*- 4 1.2 riastrad * Copyright (c) 2013 The NetBSD Foundation, Inc. 5 1.2 riastrad * All rights reserved. 6 1.2 riastrad * 7 1.2 riastrad * This code is derived from software contributed to The NetBSD Foundation 8 1.2 riastrad * by Taylor R. Campbell. 9 1.2 riastrad * 10 1.2 riastrad * Redistribution and use in source and binary forms, with or without 11 1.2 riastrad * modification, are permitted provided that the following conditions 12 1.2 riastrad * are met: 13 1.2 riastrad * 1. Redistributions of source code must retain the above copyright 14 1.2 riastrad * notice, this list of conditions and the following disclaimer. 15 1.2 riastrad * 2. Redistributions in binary form must reproduce the above copyright 16 1.2 riastrad * notice, this list of conditions and the following disclaimer in the 17 1.2 riastrad * documentation and/or other materials provided with the distribution. 18 1.2 riastrad * 19 1.2 riastrad * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 1.2 riastrad * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 1.2 riastrad * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 1.2 riastrad * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 1.2 riastrad * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 1.2 riastrad * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 1.2 riastrad * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 1.2 riastrad * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 1.2 riastrad * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 1.2 riastrad * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 1.2 riastrad * POSSIBILITY OF SUCH DAMAGE. 30 1.2 riastrad */ 31 1.2 riastrad 32 1.2 riastrad #ifndef _LINUX_HASH_H_ 33 1.2 riastrad #define _LINUX_HASH_H_ 34 1.2 riastrad 35 1.4 riastrad #include <sys/param.h> 36 1.2 riastrad #include <machine/limits.h> 37 1.2 riastrad 38 1.2 riastrad static inline unsigned long 39 1.2 riastrad hash_long(unsigned long value, unsigned int bits) 40 1.2 riastrad { 41 1.2 riastrad const unsigned long factor = (sizeof(factor) > 4? 42 1.2 riastrad 0x9e37fffffffc0001ull : 0x9e370001ul); 43 1.2 riastrad 44 1.2 riastrad return ((value * factor) >> ((CHAR_BIT * sizeof(value)) - bits)); 45 1.2 riastrad } 46 1.2 riastrad 47 1.3 riastrad static inline uint32_t 48 1.3 riastrad hash_32(uint32_t value, unsigned int bits) 49 1.3 riastrad { 50 1.3 riastrad return (value * 0x61c88647) >> (32 - bits); 51 1.3 riastrad } 52 1.3 riastrad 53 1.5 riastrad static inline uint64_t 54 1.5 riastrad hash_64(uint64_t value, unsigned int bits) 55 1.5 riastrad { 56 1.5 riastrad return (value * 0x61c8864680b583ebull) >> (64 - bits); 57 1.5 riastrad } 58 1.5 riastrad 59 1.2 riastrad #endif /* _LINUX_HASH_H_ */ 60
Indexes created Sat Sep 27 22:09:54 GMT 2025