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      1 /*	$NetBSD: hashtable.h,v 1.6 2021/12/19 12:02:40 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2018 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _LINUX_HASHTABLE_H_
     33 #define _LINUX_HASHTABLE_H_
     34 
     35 #include <sys/cdefs.h>
     36 
     37 #include <linux/hash.h>
     38 #include <linux/list.h>
     39 
     40 #define DECLARE_HASHTABLE(name, bits)					      \
     41 	struct hlist_head name[1u << (bits)]
     42 
     43 static inline void
     44 __hash_init(struct hlist_head *hash, unsigned n)
     45 {
     46 
     47 	while (n --> 0)
     48 		INIT_HLIST_HEAD(&hash[n]);
     49 }
     50 
     51 static inline bool
     52 __hash_empty(struct hlist_head *hash, unsigned n)
     53 {
     54 
     55 	while (n --> 0) {
     56 		if (!hlist_empty(&hash[n]))
     57 			return false;
     58 	}
     59 
     60 	return true;
     61 }
     62 
     63 #define	hash_init(h)		__hash_init((h), __arraycount(h))
     64 #define	hash_add(h, n, k)	hlist_add_head(n, &(h)[(k) % __arraycount(h)])
     65 #define	hash_del(n)		hlist_del_init(n)
     66 #define	hash_empty(h)		__hash_empty((h), __arraycount(h))
     67 #define	hash_for_each_possible(h, n, f, k)				      \
     68 	hlist_for_each_entry(n, &(h)[(k) % __arraycount(h)], f)
     69 #define	hash_for_each_safe(h, i, t, n, f)				      \
     70 	for ((i) = 0; (i) < __arraycount(h); (i)++)			      \
     71 		hlist_for_each_entry_safe(n, t, &(h)[i], f)
     72 
     73 #endif /*_LINUX_HASHTABLE_H_*/
     74