Import of Empire 4.2.12

src/lib/as/as_costcomp.c

@@ -0,0 +1,49 @@
+/*
+ *  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);
+}