usr/src/cmd/refer/shell.c

   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 #pragma ident   "%Z%%M% %I%     %E% SMI"
  16
  17 /*
  18  * SORTS UP.
  19  * IF THERE ARE NO EXCHANGES (IEX=0) ON A SWEEP
  20  * THE COMPARISON GAP (IGAP) IS HALVED FOR THE NEXT SWEEP
  21  */
  22 void
  23 shell(int n, int (*comp)(), int (*exch)())
  24 {
  25         int igap, iplusg, iex, i, imax;
  26         igap = n;
  27         while (igap > 1) {
  28                 igap /= 2;
  29                 imax = n-igap;
  30                 do {
  31                         iex = 0;
  32                         for (i = 0; i < imax; i++) {
  33                                 iplusg = i + igap;
  34                                 if ((*comp)(i, iplusg)) continue;
  35                                 (*exch) (i, iplusg);
  36                                 iex = 1;
  37                         }
  38                 }
  39                 while (iex > 0)
  40                         ;
  41         }
  42 }