O1_size_impl.hpp

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#ifndef BOOST_MPL_O1_SIZE_IMPL_HPP_INCLUDED
#define BOOST_MPL_O1_SIZE_IMPL_HPP_INCLUDED
 
// Copyright Aleksey Gurtovoy 2000-2004
//
// 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)
//
// See http://www.boost.org/libs/mpl for documentation.
 
// $Id: O1_size_impl.hpp 13472 2017-08-22 07:53:44Z richean $
// $Date: 2017-08-22 09:53:44 +0200 (Di, 22 Aug 2017) $
// $Revision: 13472 $
 
#include <boost/mpl/O1_size_fwd.hpp>
#include <boost/mpl/long.hpp>
#include <boost/mpl/if.hpp>
#include <boost/mpl/aux_/has_size.hpp>
#include <boost/mpl/aux_/config/forwarding.hpp>
#include <boost/mpl/aux_/config/static_constant.hpp>
#include <boost/mpl/aux_/config/msvc.hpp>
#include <boost/mpl/aux_/config/workaround.hpp>
 
namespace boost { namespace mpl {
 
// default implementation - returns 'Sequence::size' if sequence has a 'size'
// member, and -1 otherwise; conrete sequences might override it by 
// specializing either the 'O1_size_impl' or the primary 'O1_size' template
 
#   if !BOOST_WORKAROUND(BOOST_MSVC, < 1300) \
    && !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
 
namespace aux {
template< typename Sequence > struct O1_size_impl
    : Sequence::size
{
};
}
 
template< typename Tag >
struct O1_size_impl
{
    template< typename Sequence > struct apply
#if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING)
        : if_<
              aux::has_size<Sequence>
            , aux::O1_size_impl<Sequence>
            , long_<-1>
            >::type
    {
#else
    {
        typedef typename if_<
              aux::has_size<Sequence>
            , aux::O1_size_impl<Sequence>
            , long_<-1>
            >::type type;
 
        BOOST_STATIC_CONSTANT(long, value =
              (if_<
                  aux::has_size<Sequence>
                , aux::O1_size_impl<Sequence>
                , long_<-1>
                >::type::value)
            );
#endif
    };
};
 
#   else // BOOST_MSVC
 
template< typename Tag >
struct O1_size_impl
{
    template< typename Sequence > struct apply
        : long_<-1>
        {
        };
};
 
#   endif
 
}}
 
#endif // BOOST_MPL_O1_SIZE_IMPL_HPP_INCLUDED