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diff --git a/contrib/gcc/et-forest.h b/contrib/gcc/et-forest.h
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+/* Et-forest data structure implementation.  
+   Copyright (C) 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., 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 ancesto.
+ 
+   ET tree strores 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 sligtly 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 PARAMS ((void));
+
+extern void et_forest_delete PARAMS ((et_forest_t));
+
+extern et_forest_node_t et_forest_add_node PARAMS ((et_forest_t, void *));
+extern int et_forest_add_edge PARAMS ((et_forest_t, et_forest_node_t, 
+					et_forest_node_t));
+extern void et_forest_remove_node PARAMS ((et_forest_t, et_forest_node_t));
+extern int et_forest_remove_edge PARAMS ((et_forest_t, et_forest_node_t,
+					   et_forest_node_t));
+extern et_forest_node_t et_forest_parent PARAMS ((et_forest_t, et_forest_node_t));
+extern et_forest_node_t et_forest_common_ancestor PARAMS ((et_forest_t,
+							  et_forest_node_t,
+							  et_forest_node_t));
+extern void * et_forest_node_value PARAMS ((et_forest_t, et_forest_node_t));
+extern int et_forest_enumerate_sons PARAMS ((et_forest_t, et_forest_node_t,
+					     et_forest_node_t *));
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* _ET_TREE_H */