xref: /illumos-gate/usr/src/cmd/refer/shell.c (revision 9b9d39d2a32ff806d2431dbcc50968ef1e6d46b2)
1 /*
2  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 
6 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
7 /*	  All Rights Reserved  	*/
8 
9 /*
10  * Copyright (c) 1980 Regents of the University of California.
11  * All rights reserved. The Berkeley software License Agreement
12  * specifies the terms and conditions for redistribution.
13  */
14 
15 /*
16  * SORTS UP.
17  * IF THERE ARE NO EXCHANGES (IEX=0) ON A SWEEP
18  * THE COMPARISON GAP (IGAP) IS HALVED FOR THE NEXT SWEEP
19  */
20 void
21 shell(int n, int (*comp)(), int (*exch)())
22 {
23 	int igap, iplusg, iex, i, imax;
24 	igap = n;
25 	while (igap > 1) {
26 		igap /= 2;
27 		imax = n-igap;
28 		do {
29 			iex = 0;
30 			for (i = 0; i < imax; i++) {
31 				iplusg = i + igap;
32 				if ((*comp)(i, iplusg)) continue;
33 				(*exch) (i, iplusg);
34 				iex = 1;
35 			}
36 		}
37 		while (iex > 0)
38 			;
39 	}
40 }
41