empserver/src/lib/as/as_costcomp.c

49 lines
1.5 KiB
C

/*
* A* Search - A search library used in Empire to determine paths between
* objects.
* Copyright (C) 1990-1998 Phil Lapsley
*
* 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
*/
#include "as.h"
#if !defined(lint) && !defined(SABER)
static char sccsid[] = "@(#)as_costcomp.c 1.4 11/13/90";
#endif /* not lint */
/*
* Compare the lower bound costs of two nodes. If the two nodes have
* equal lower bound costs, sort on the secondary field.
* Used as comparision function for qsort.
*/
int
as_costcomp(struct as_node **n1, struct as_node **n2)
{
double diff;
diff = (*n1)->lbcost - (*n2)->lbcost;
if (diff < -0.0001)
return (-1);
if (diff > 0.0001)
return (1);
/* equal, check secondary cost */
diff = (*n1)->seccost - (*n2)->seccost;
if (diff < -0.0001)
return (-1);
if (diff > 0.0001)
return (1);
return (0);
}