/* Produced by texiweb from libavl.w on 2002/02/09 at 01:45. */

/* libavl - library for manipulation of binary trees.
   Copyright (C) 1998-2002 Free Software Foundation, Inc.

   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 Street, Fifth Floor, Boston, MA 02110-1301 USA

   The author may be contacted at <blp@gnu.org> on the Internet, or
   as Ben Pfaff, 12167 Airport Rd, DeWitt MI 48820, USA through more
   mundane means.
 */

#ifndef TAVL_H
#define TAVL_H 1

#include <stddef.h>

/* Function types. */
typedef int tavl_comparison_func(const void *tavl_a, const void *tavl_b,
				 void *tavl_param);
typedef void tavl_item_func(void *tavl_item, void *tavl_param);
typedef void *tavl_copy_func(void *tavl_item, void *tavl_param);

#ifndef LIBAVL_ALLOCATOR
#define LIBAVL_ALLOCATOR
/* Memory allocator. */
struct libavl_allocator
{
    void *(*libavl_malloc) (struct libavl_allocator *, size_t libavl_size);
    void (*libavl_free) (struct libavl_allocator *, void *libavl_block);
};
#endif

/* Default memory allocator. */
extern struct libavl_allocator tavl_allocator_default;
void *tavl_malloc(struct libavl_allocator *, size_t);
void tavl_free(struct libavl_allocator *, void *);

/* Maximum TAVL height. */
#ifndef TAVL_MAX_HEIGHT
#define TAVL_MAX_HEIGHT 32
#endif

/* Tree data structure. */
struct tavl_table
{
    struct tavl_node *tavl_root;	/* Tree's root. */
    tavl_comparison_func *tavl_compare;	/* Comparison function. */
    void *tavl_param;		/* Extra argument to |tavl_compare|. */
    struct libavl_allocator *tavl_alloc;	/* Memory allocator. */
    size_t tavl_count;		/* Number of items in tree. */
};

/* Characterizes a link as a child pointer or a thread. */
enum tavl_tag
{
    TAVL_CHILD,			/* Child pointer. */
    TAVL_THREAD			/* Thread. */
};

/* An TAVL tree node. */
struct tavl_node
{
    struct tavl_node *tavl_link[2];	/* Subtrees. */
    void *tavl_data;		/* Pointer to data. */
    unsigned char tavl_tag[2];	/* Tag fields. */
    signed char tavl_balance;	/* Balance factor. */
};

/* TAVL traverser structure. */
struct tavl_traverser
{
    struct tavl_table *tavl_table;	/* Tree being traversed. */
    struct tavl_node *tavl_node;	/* Current node in tree. */
};

/* Table functions. */
struct tavl_table *tavl_create(tavl_comparison_func *, void *,
			       struct libavl_allocator *);
struct tavl_table *tavl_copy(const struct tavl_table *, tavl_copy_func *,
			     tavl_item_func *, struct libavl_allocator *);
void tavl_destroy(struct tavl_table *, tavl_item_func *);
void **tavl_probe(struct tavl_table *, void *);
void *tavl_insert(struct tavl_table *, void *);
void *tavl_replace(struct tavl_table *, void *);
void *tavl_delete(struct tavl_table *, const void *);
void *tavl_find(const struct tavl_table *, const void *);
void tavl_assert_insert(struct tavl_table *, void *);
void *tavl_assert_delete(struct tavl_table *, void *);

#define tavl_count(table) ((size_t) (table)->tavl_count)

/* Table traverser functions. */
void tavl_t_init(struct tavl_traverser *, struct tavl_table *);
void *tavl_t_first(struct tavl_traverser *, struct tavl_table *);
void *tavl_t_last(struct tavl_traverser *, struct tavl_table *);
void *tavl_t_find(struct tavl_traverser *, struct tavl_table *, void *);
void *tavl_t_insert(struct tavl_traverser *, struct tavl_table *, void *);
void *tavl_t_copy(struct tavl_traverser *, const struct tavl_traverser *);
void *tavl_t_next(struct tavl_traverser *);
void *tavl_t_prev(struct tavl_traverser *);
void *tavl_t_cur(struct tavl_traverser *);
void *tavl_t_replace(struct tavl_traverser *, void *);

#endif /* tavl.h */
