diff options
author | Anas Nashif <anas.nashif@intel.com> | 2012-10-30 12:57:26 -0700 |
---|---|---|
committer | Anas Nashif <anas.nashif@intel.com> | 2012-10-30 12:57:26 -0700 |
commit | 1a78a62555be32868418fe52f8e330c9d0f95d5a (patch) | |
tree | d3765a80e7d3b9640ec2e930743630cd6b9fce2b /boost/pending/lowest_bit.hpp | |
download | boost-1a78a62555be32868418fe52f8e330c9d0f95d5a.tar.gz boost-1a78a62555be32868418fe52f8e330c9d0f95d5a.tar.bz2 boost-1a78a62555be32868418fe52f8e330c9d0f95d5a.zip |
Imported Upstream version 1.49.0upstream/1.49.0
Diffstat (limited to 'boost/pending/lowest_bit.hpp')
-rw-r--r-- | boost/pending/lowest_bit.hpp | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/boost/pending/lowest_bit.hpp b/boost/pending/lowest_bit.hpp new file mode 100644 index 0000000000..dd6e6e8c9e --- /dev/null +++ b/boost/pending/lowest_bit.hpp @@ -0,0 +1,39 @@ +// ----------------------------------------------------------- +// 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 |