avl.h

/*
 * avl.h - this file is part of Libtree.
 * $Id: avl.h 2632 2021-05-03 06:38:18Z soci $
 *
 * Copyright (C) 2010 Franck Bui-Huu <fbuihuu@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; version 2 of the
 * License.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 */
#ifndef AVL_H
#define AVL_H

#include <stddef.h>
#include "attributes.h"

/*
 * The definition has been stolen from the Linux kernel.
 */
#ifdef __GNUC__
#  define avltree_container_of(node, type, member) ({                   \
        struct avltree_node *__mptr = (node);                   \
        (type *)( (char *)__mptr - offsetof(type,member) );})
#  define cavltree_container_of(node, type, member) ({                  \
        const struct avltree_node *__mptr = (node);                     \
        (const type *)( (const char *)__mptr - offsetof(type,member) );})
#else
#  define avltree_container_of(node, type, member)                      \
        ((type *)((char *)(node) - offsetof(type, member)))
#  define cavltree_container_of(node, type, member)                     \
        ((const type *)((const char *)(node) - offsetof(type, member)))
#endif  /* __GNUC__ */

/*
 * AVL tree
 */

struct avltree_node {
    struct avltree_node *left, *right;
    struct avltree_node *parent;
    signed char balance;            /* balance factor [-2:+2] */
};

typedef FAST_CALL int (*avltree_cmp_fn_t)(const struct avltree_node *, const struct avltree_node *);
typedef void (*avltree_free_fn_t)(struct avltree_node *);

struct avltree {
    struct avltree_node *root;
};

static inline void avltree_init(struct avltree *tree) {
    tree->root = NULL;
}

extern FAST_CALL struct avltree_node *avltree_lookup(const struct avltree_node *, const struct avltree *, avltree_cmp_fn_t);
extern struct avltree_node *avltree_insert(struct avltree_node *, struct avltree *, avltree_cmp_fn_t);
extern void avltree_remove(struct avltree_node *, struct avltree *);
extern void avltree_destroy(struct avltree *, avltree_free_fn_t);

#endif