/* Et-forest data structure implementation.
   Copyright (C) 2002, 2003 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* This package implements ET forest data structure. Each tree in
   the structure maintains a tree structure and offers logarithmic time
   for tree operations (insertion and removal of nodes and edges) and
   poly-logarithmic time for nearest common ancestor.

   ET tree stores its structue as a sequence of symbols obtained
   by dfs(root)

   dfs (node)
   {
     s = node;
     for each child c of node do
       s = concat (s, c, node);
     return s;
   }

   For example for tree

            1
          / | \
         2  3  4
       / |
      4  5

   the sequence is 1 2 4 2 5 3 1 3 1 4 1.

   The sequence is stored in a slightly modified splay tree.
   In order to support various types of node values, a hashtable
   is used to convert node values to the internal representation.  */

#ifndef _ET_TREE_H
#define _ET_TREE_H

#include <ansidecl.h>
#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

typedef struct et_forest *et_forest_t;
typedef struct et_forest_node *et_forest_node_t;

extern et_forest_t et_forest_create (void);

extern void et_forest_delete (et_forest_t);

extern et_forest_node_t et_forest_add_node (et_forest_t, void *);
extern int et_forest_add_edge (et_forest_t, et_forest_node_t,
			       et_forest_node_t);
extern void et_forest_remove_node (et_forest_t, et_forest_node_t);
extern int et_forest_remove_edge (et_forest_t, et_forest_node_t,
				  et_forest_node_t);
extern et_forest_node_t et_forest_parent (et_forest_t, et_forest_node_t);
extern et_forest_node_t et_forest_common_ancestor (et_forest_t,
						   et_forest_node_t,
						   et_forest_node_t);
extern void * et_forest_node_value (et_forest_t, et_forest_node_t);
extern int et_forest_enumerate_sons (et_forest_t, et_forest_node_t,
				     et_forest_node_t *);

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif /* _ET_TREE_H */