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Filename : tsearch.h
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/* Binary tree data structure.
   Copyright (C) 2006, 2015-2016 Free Software Foundation, Inc.

   This program 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 2.1 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 Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#ifndef _TSEARCH_H
#define _TSEARCH_H

#if HAVE_TSEARCH

/* Get tseach(), tfind(), tdelete(), twalk() declarations.  */
#include <search.h>

#else

#ifdef __cplusplus
extern "C" {
#endif

/* See <http://www.opengroup.org/susv3xbd/search.h.html>,
       <http://www.opengroup.org/susv3xsh/tsearch.html>
   for details.  */

typedef enum
{ 
  preorder,
  postorder, 
  endorder,
  leaf
}
VISIT;

/* Searches an element in the tree *VROOTP that compares equal to KEY.
   If one is found, it is returned.  Otherwise, a new element equal to KEY
   is inserted in the tree and is returned.  */
extern void * tsearch (const void *key, void **vrootp,
                       int (*compar) (const void *, const void *));

/* Searches an element in the tree *VROOTP that compares equal to KEY.
   If one is found, it is returned.  Otherwise, NULL is returned.  */
extern void * tfind (const void *key, void *const *vrootp,
                     int (*compar) (const void *, const void *));

/* Searches an element in the tree *VROOTP that compares equal to KEY.
   If one is found, it is removed from the tree, and its parent node is
   returned.  Otherwise, NULL is returned.  */
extern void * tdelete (const void *key, void **vrootp,
                       int (*compar) (const void *, const void *));

/* Perform a depth-first, left-to-right traversal of the tree VROOT.
   The ACTION function is called:
     - for non-leaf nodes: 3 times, before the left subtree traversal,
       after the left subtree traversal but before the right subtree traversal,
       and after the right subtree traversal,
     - for leaf nodes: once.
   The arguments passed to ACTION are:
     1. the node; it can be casted to a 'const void * const *', i.e. into a
        pointer to the key,
     2. an indicator which visit of the node this is,
     3. the level of the node in the tree (0 for the root).  */
extern void twalk (const void *vroot,
                   void (*action) (const void *, VISIT, int));

#ifdef __cplusplus
}
#endif

#endif

#endif /* _TSEARCH_H */