// -------------------------------------

// lowest_bit.hpp

//

//           Position of the lowest bit 'on'

//

//       (C) Copyright Gennaro Prota 2003 - 2004.

//

// Distributed under the Boost Software License, Version 1.0.

//    (See accompanying file LICENSE_1_0.txt or copy at

//          http://www.boost.org/LICENSE_1_0.txt)

//

// ------------------------------------------------------

//

// $Id: lowest_bit.hpp 41369 2007-11-25 18:07:19Z bemandawes $



#ifndef BOOST_LOWEST_BIT_HPP_GP_20030301

#define BOOST_LOWEST_BIT_HPP_GP_20030301



#include <assert.h>

#include "boost/pending/integer_log2.hpp"





namespace boost {



    template <typename T>

    int lowest_bit(T x) {



        assert(x >= 1); // PRE



        // clear all bits on except the rightmost one,

        // then calculate the logarithm base 2

        //

        return boost::integer_log2<T>( x - ( x & (x-1) ) );



    }





}





#endif // include guard

