//-----------------------------------------------------------------------------
// 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/map
// 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.
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// file		map_reverse.c
//-----------------------------------------------------------------------------

#include "map_lib.h"

#if 0
//-----------------------------------------------------------------------------
// struct	map_link
// struct	map_node
//
// purpose	Define structures needed to keep the AVL trees used to hold
//		the mapping.
//-----------------------------------------------------------------------------
struct map_link {
    avl_link		link	;
    // The key is found here in the type specific structs.
};
struct map_node {
    struct map_mixed	data	;
    struct map_link	link	;
};
#endif

__PROTO_BEGIN__
//-----------------------------------------------------------------------------
// function	map_reverse
//
// purpose	Move the current member selection of a mapping one step in
//		the reverse direction.	If there is no current member, then
//		select the last member.
//
// arguments	1 (MAP) mapping handle
//
// returns	(int) -2 = error, no map
//		(int) -1 = no member found
//		(int)  0 = member found, no data
//		(int) >0 = member found, data type returned
//-----------------------------------------------------------------------------
int
map_reverse (
    MAP		arg_map
    )
__PROTO_END__
{
    struct map_node *	node_p	;

    //-- Make sure we have a mapping.
    if ( ! arg_map ) return -2;

    //-- Let the AVL layer find the next reverse member.
    node_p = avl_reverse( & (arg_map->avl_tree), NULL );

    //-- Return the found data type or -1 if none found.
    return ( node_p ) ? node_p->data.type : -1;
}