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rbtree.h revision 1.7 
      1 /*	$NetBSD: rbtree.h,v 1.7 2021/12/19 01:44:33 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 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_RBTREE_H_
     33 #define _LINUX_RBTREE_H_
     34 
     35 #include <sys/rbtree.h>
     36 
     37 struct rb_root {
     38 	struct rb_tree	rbr_tree;
     39 };
     40 
     41 struct rb_root_cached {
     42 	struct rb_root	rbrc_root;
     43 };
     44 
     45 static inline bool
     46 RB_EMPTY_ROOT(struct rb_root *root)
     47 {
     48 
     49 	return RB_TREE_MIN(&root->rbr_tree) == NULL;
     50 }
     51 
     52 static inline void
     53 rb_erase(struct rb_node *rbnode, struct rb_root *root)
     54 {
     55 	struct rb_tree *tree = &root->rbr_tree;
     56 	void *node = (char *)rbnode - tree->rbt_ops->rbto_node_offset;
     57 
     58 	rb_tree_remove_node(tree, node);
     59 }
     60 
     61 static inline void
     62 rb_erase_cached(struct rb_node *rbnode, struct rb_root_cached *root)
     63 {
     64 	rb_erase(rbnode, &root->rbrc_root);
     65 }
     66 
     67 /*
     68  * XXX This is not actually postorder, but I can't fathom why you would
     69  * want postorder for an ordered tree; different insertion orders lead
     70  * to different traversal orders.
     71  */
     72 #define	rbtree_postorder_for_each_entry_safe(NODE, TMP, ROOT, FIELD)	      \
     73 	for ((NODE) = RB_TREE_MIN(&(ROOT)->rbr_tree);			      \
     74 		((NODE) != NULL &&					      \
     75 		    ((TMP) = rb_tree_iterate(&(ROOT)->rbr_tree, (NODE),	      \
     76 			RB_DIR_RIGHT)));				      \
     77 		(NODE) = (TMP))
     78 
     79 #endif  /* _LINUX_RBTREE_H_ */
     80