/*
 * Copyright (C) 2012 by Darren Reed.
 *
 * See the IPFILTER.LICENCE file for details on licencing.
 *
 * $Id$
 */

#include "ipf.h"


/*
 * count consecutive 1's in bit mask.  If the mask generated by counting
* consecutive 1's is different to that passed, return -1, else return #
 * of bits.
 */
int
count4bits(u_int ip)
{
        int cnt = 0, i, j;
        u_int ipn;

        ip = ipn = ntohl(ip);
        for (i = 32; i; i--, ipn *= 2)
                if (ipn & 0x80000000)
                        cnt++;
                else
                        break;
        ipn = 0;
        for (i = 32, j = cnt; i; i--, j--) {
                ipn *= 2;
                if (j > 0)
                        ipn++;
        }
        if (ipn == ip)
                return (cnt);
        return (-1);
}