Init

usr.bin/refer/shell.c

@@ -0,0 +1,31 @@
+#ifndef lint
+static char sccsid[] = "@(#)shell.c 1.1 94/10/31 SMI"; /* from UCB 4.1 5/6/83 */
+#endif
+/*
+ * SORTS UP.
+ * IF THERE ARE NO EXCHANGES (IEX=0) ON A SWEEP
+ * THE COMPARISON GAP (IGAP) IS HALVED FOR THE NEXT SWEEP
+ */
+shell (n, comp, exch)
+int (*comp)(), (*exch)();
+{
+	int igap, iplusg, iex, i, imax;
+	igap=n;
+	while (igap > 1)
+	{
+		igap /= 2;
+		imax = n-igap;
+		do
+		    {
+			iex=0;
+			for(i=0; i<imax; i++)
+			{
+				iplusg = i + igap;
+				if ((*comp) (i, iplusg) ) continue;
+				(*exch) (i, iplusg);
+				iex=1;
+			}
+		} 
+		while (iex>0);
+	}
+}