rbtree.h

/*
 * Red Black Trees
 * This file is part of mtrace-ng.
 *  This file is based on the linux kernel source
 *   Copyright (C) 1999  Andrea Arcangeli <andrea@suse.de>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#ifndef _INC_RBTREE_H
#define _INC_RBTREE_H

#include <stdlib.h>

#include "common.h"

struct rb_node
{
	unsigned long  rb_parent_color;
#define	RB_RED		0
#define	RB_BLACK	1
	struct rb_node *rb_right;
	struct rb_node *rb_left;
} __attribute__((aligned(sizeof(long))));

struct rb_root
{
	struct rb_node *rb_node;
};

#define RB_ROOT	(struct rb_root) { NULL, }

void rb_insert_color(struct rb_node *, struct rb_root *);
void rb_erase(struct rb_node *, struct rb_root *);

/* Postorder iteration - always visit the parent after its children */
struct rb_node *rb_first_postorder(const struct rb_root *);
struct rb_node *rb_next_postorder(const struct rb_node *);

/* Find logical next and previous nodes in a tree */
struct rb_node *rb_next(const struct rb_node *);
struct rb_node *rb_prev(const struct rb_node *);
struct rb_node *rb_first(const struct rb_root *);
struct rb_node *rb_last(const struct rb_root *);

static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
				struct rb_node **rb_link)
{
	node->rb_parent_color = (unsigned long )parent;
	node->rb_left = node->rb_right = NULL;

	*rb_link = node;
}

int rb_iterate(const struct rb_root *root, int (*func)(struct rb_node *,void *data), void *user);

#define	rb_entry(ptr, type, member) container_of(ptr, type, member)

#define rb_entry_safe(ptr, type, member) \
	({ typeof(ptr) ____ptr = (ptr); \
	   ____ptr ? rb_entry(____ptr, type, member) : NULL; \
	})

/**
 * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
 * given type safe against removal of rb_node entry
 *
 * @pos:	the 'type *' to use as a loop cursor.
 * @n:		another 'type *' to use as temporary storage
 * @root:	'rb_root *' of the rbtree.
 * @field:	the name of the rb_node field within 'type'.
 */
#define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
	for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
	     pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
			typeof(*pos), field); 1; }); \
	     pos = n)

#endif