mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2025-06-05 00:02:25 -04:00
ecaa982b9f
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7593 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
40 lines
925 B
C++
40 lines
925 B
C++
// -----------------------------------------------------------
|
|
// lowest_bit.hpp
|
|
//
|
|
// Position of the lowest bit 'on'
|
|
//
|
|
// Copyright (c) 2003-2004, 2008 Gennaro Prota
|
|
//
|
|
// 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)
|
|
//
|
|
// -----------------------------------------------------------
|
|
|
|
#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
|