/* libavl - library for manipulation of binary trees.
   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004 Free Software
   Foundation, Inc.

   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; either
   version 3 of the License, or (at your option) any later version.

   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 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 */