usr/src/old/refer/hunt/shell.c

/*-
 * This module is believed to contain source code proprietary to AT&T.
 * Use and redistribution is subject to the Berkeley Software License
 * Agreement and your Software Agreement with AT&T (Western Electric).
 */

#ifndef lint
static char sccsid[] = "@(#)shell.c     4.2 (Berkeley) 4/18/91";
#endif /* not lint */

/*
 * 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);
        }
}