ceph/src/boost/libs/log/src/alignment_gap_between.hpp

   1 /*
   2  *          Copyright Andrey Semashev 2007 - 2015.
   3  * Distributed under the Boost Software License, Version 1.0.
   4  *    (See accompanying file LICENSE_1_0.txt or copy at
   5  *          http://www.boost.org/LICENSE_1_0.txt)
   6  */
   7 /*!
   8  * \file   alignment_gap_between.hpp
   9  * \author Andrey Semashev
  10  * \date   20.11.2007
  11  *
  12  * \brief  This header is the Boost.Log library implementation, see the library documentation
  13  *         at http://www.boost.org/doc/libs/release/libs/log/doc/html/index.html.
  14  */
  15
  16 #ifndef BOOST_LOG_ALIGNMENT_GAP_BETWEEN_HPP_INCLUDED_
  17 #define BOOST_LOG_ALIGNMENT_GAP_BETWEEN_HPP_INCLUDED_
  18
  19 #include <boost/log/detail/config.hpp>
  20 #include <boost/type_traits/alignment_of.hpp>
  21 #include <boost/log/detail/header.hpp>
  22
  23 namespace boost {
  24
  25 BOOST_LOG_OPEN_NAMESPACE
  26
  27 namespace aux {
  28
  29 //! The metafunction computes the minimal gap between objects t1 and t2 of types T1 and T2
  30 //! that would be needed to maintain the alignment of t2 if it's placed right after t1
  31 template< typename T1, typename T2 >
  32 struct alignment_gap_between
  33 {
  34     enum _
  35     {
  36         T2_alignment = boost::alignment_of< T2 >::value,
  37         tail_size = sizeof(T1) % T2_alignment,
  38         value = tail_size > 0 ? T2_alignment - tail_size : 0
  39     };
  40 };
  41
  42 } // namespace aux
  43
  44 BOOST_LOG_CLOSE_NAMESPACE // namespace log
  45
  46 } // namespace boost
  47
  48 #include <boost/log/detail/footer.hpp>
  49
  50 #endif // BOOST_LOG_ALIGNMENT_GAP_BETWEEN_HPP_INCLUDED_