//-----------------------------------------------------------------------------
// Copyright © 2003 - Philip Howard - All rights reserved
//
// 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.
//-----------------------------------------------------------------------------
// package	libh/avl
// homepage	http://libh.slashusr.org/
//-----------------------------------------------------------------------------
// author	Philip Howard
// email	libh at ipal dot org
// homepage	http://phil.ipal.org/
//-----------------------------------------------------------------------------
// This file is best viewed using a fixed spaced font such as Courier
// and in a display at least 120 columns wide.
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// G. M. Adelson-Velskii and E. M. Landis are the inventors of the algorithm
// bearing their initials, AVL.  Their algorithm for height-balanced binary
// search trees is the basis of the code in this package.  Some modification
// is made to the balancing operations, and features are added for practical
// purposes.
//-----------------------------------------------------------------------------

#include "avl_lib.h"

__PROTO_BEGIN__
//-----------------------------------------------------------------------------
// function	avl_iterate
//
// purpose	Execute a given function once for each node in the given
//		binary tree.  Iteration is done in forward order.
//
// arguments	1 (AVL *) pointer to binary tree
//		2 (void (*fun)(void *)) pointer to function to execute
//
// returns	(long) sum of return values or error code.
//
// callback	The function specified in argument 2 is called with:
//   arguments	1 (void *) pointer to node
//   returns	(void) ignored
//
// warning	Do NOT delete the current node from the tree during the
//		function being called with it.
//-----------------------------------------------------------------------------
long
avl_iterate(
    AVL *		arg_tree
    ,
    int			( (* arg_fun)(void *) )
    )
__PROTO_END__
{
    avl_link *		link_p		;
    avl_link *		prev_p		;
    long		count		;

#ifdef AVL_CHECK_ARGS
    //---------------------------------
    // Make sure we have a binary tree.
    //---------------------------------
    if ( ! arg_tree ) return AVL_ERR_BAD_ROOT;

    //--------------------------------------
    // Make sure we have a function to call.
    //--------------------------------------
    if ( ! arg_fun ) return 0;
#endif

    count = 0;

    if ( ! ( link_p = ( prev_p = & ( arg_tree->link ) )->hi ) ) return 0;

    while ( link_p != & ( arg_tree->link ) ) {
	if ( prev_p == link_p->pa ) {
	    if ( link_p->lo ) {
		prev_p = link_p;
		link_p = link_p->lo;
		continue;
	    }
	    prev_p = link_p->lo;
	}
	if ( prev_p == link_p->lo ) {
	    count += (* arg_fun)( (void *) avl_link_to_node( arg_tree, link_p ) );
	    if ( link_p->hi ) {
		prev_p = link_p;
		link_p = link_p->hi;
		continue;
	    }
	    prev_p = link_p->hi;
	}
	prev_p = link_p;
	link_p = link_p->pa;
	continue;
    }

    return count;
}