xref: /titanic_53/usr/src/cmd/refer/shell.c (revision 7c478bd95313f5f23a4c958a745db2134aa03244)
1*7c478bd9Sstevel@tonic-gate /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
2*7c478bd9Sstevel@tonic-gate /*	  All Rights Reserved  	*/
3*7c478bd9Sstevel@tonic-gate 
4*7c478bd9Sstevel@tonic-gate 
5*7c478bd9Sstevel@tonic-gate /*
6*7c478bd9Sstevel@tonic-gate  * Copyright (c) 1980 Regents of the University of California.
7*7c478bd9Sstevel@tonic-gate  * All rights reserved. The Berkeley software License Agreement
8*7c478bd9Sstevel@tonic-gate  * specifies the terms and conditions for redistribution.
9*7c478bd9Sstevel@tonic-gate  */
10*7c478bd9Sstevel@tonic-gate 
11*7c478bd9Sstevel@tonic-gate /*
12*7c478bd9Sstevel@tonic-gate  * Copyright (c) 1983, 1984 1985, 1986, 1987, 1988, Sun Microsystems, Inc.
13*7c478bd9Sstevel@tonic-gate  * All Rights Reserved.
14*7c478bd9Sstevel@tonic-gate  */
15*7c478bd9Sstevel@tonic-gate 
16*7c478bd9Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
17*7c478bd9Sstevel@tonic-gate 
18*7c478bd9Sstevel@tonic-gate /*
19*7c478bd9Sstevel@tonic-gate  * SORTS UP.
20*7c478bd9Sstevel@tonic-gate  * IF THERE ARE NO EXCHANGES (IEX=0) ON A SWEEP
21*7c478bd9Sstevel@tonic-gate  * THE COMPARISON GAP (IGAP) IS HALVED FOR THE NEXT SWEEP
22*7c478bd9Sstevel@tonic-gate  */
23*7c478bd9Sstevel@tonic-gate shell (n, comp, exch)
24*7c478bd9Sstevel@tonic-gate int (*comp)(), (*exch)();
25*7c478bd9Sstevel@tonic-gate {
26*7c478bd9Sstevel@tonic-gate 	int igap, iplusg, iex, i, imax;
27*7c478bd9Sstevel@tonic-gate 	igap=n;
28*7c478bd9Sstevel@tonic-gate 	while (igap > 1)
29*7c478bd9Sstevel@tonic-gate 	{
30*7c478bd9Sstevel@tonic-gate 		igap /= 2;
31*7c478bd9Sstevel@tonic-gate 		imax = n-igap;
32*7c478bd9Sstevel@tonic-gate 		do
33*7c478bd9Sstevel@tonic-gate 		    {
34*7c478bd9Sstevel@tonic-gate 			iex=0;
35*7c478bd9Sstevel@tonic-gate 			for(i=0; i<imax; i++)
36*7c478bd9Sstevel@tonic-gate 			{
37*7c478bd9Sstevel@tonic-gate 				iplusg = i + igap;
38*7c478bd9Sstevel@tonic-gate 				if ((*comp) (i, iplusg) ) continue;
39*7c478bd9Sstevel@tonic-gate 				(*exch) (i, iplusg);
40*7c478bd9Sstevel@tonic-gate 				iex=1;
41*7c478bd9Sstevel@tonic-gate 			}
42*7c478bd9Sstevel@tonic-gate 		}
43*7c478bd9Sstevel@tonic-gate 		while (iex>0);
44*7c478bd9Sstevel@tonic-gate 	}
45*7c478bd9Sstevel@tonic-gate }
46