You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
136 lines
2.8 KiB
136 lines
2.8 KiB
|
|
#ifndef BOOST_MPL_IF_HPP_INCLUDED
|
|
#define BOOST_MPL_IF_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.
|
|
|
|
// $Id$
|
|
// $Date$
|
|
// $Revision$
|
|
|
|
#include <boost/mpl/aux_/value_wknd.hpp>
|
|
#include <boost/mpl/aux_/static_cast.hpp>
|
|
#include <boost/mpl/aux_/na_spec.hpp>
|
|
#include <boost/mpl/aux_/lambda_support.hpp>
|
|
#include <boost/mpl/aux_/config/integral.hpp>
|
|
#include <boost/mpl/aux_/config/ctps.hpp>
|
|
#include <boost/mpl/aux_/config/workaround.hpp>
|
|
|
|
namespace boost { namespace mpl {
|
|
|
|
#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
|
|
|
|
template<
|
|
bool C
|
|
, typename T1
|
|
, typename T2
|
|
>
|
|
struct if_c
|
|
{
|
|
typedef T1 type;
|
|
};
|
|
|
|
template<
|
|
typename T1
|
|
, typename T2
|
|
>
|
|
struct if_c<false,T1,T2>
|
|
{
|
|
typedef T2 type;
|
|
};
|
|
|
|
// agurt, 05/sep/04: nondescriptive parameter names for the sake of DigitalMars
|
|
// (and possibly MWCW < 8.0); see https://lists.boost.org/Archives/boost/2004/09/71383.php
|
|
template<
|
|
typename BOOST_MPL_AUX_NA_PARAM(T1)
|
|
, typename BOOST_MPL_AUX_NA_PARAM(T2)
|
|
, typename BOOST_MPL_AUX_NA_PARAM(T3)
|
|
>
|
|
struct if_
|
|
{
|
|
private:
|
|
// agurt, 02/jan/03: two-step 'type' definition for the sake of aCC
|
|
typedef if_c<
|
|
#if defined(BOOST_MPL_CFG_BCC_INTEGRAL_CONSTANTS)
|
|
BOOST_MPL_AUX_VALUE_WKND(T1)::value
|
|
#else
|
|
BOOST_MPL_AUX_STATIC_CAST(bool, BOOST_MPL_AUX_VALUE_WKND(T1)::value)
|
|
#endif
|
|
, T2
|
|
, T3
|
|
> almost_type_;
|
|
|
|
public:
|
|
typedef typename almost_type_::type type;
|
|
|
|
BOOST_MPL_AUX_LAMBDA_SUPPORT(3,if_,(T1,T2,T3))
|
|
};
|
|
|
|
#else
|
|
|
|
// no partial class template specialization
|
|
|
|
namespace aux {
|
|
|
|
template< bool C >
|
|
struct if_impl
|
|
{
|
|
template< typename T1, typename T2 > struct result_
|
|
{
|
|
typedef T1 type;
|
|
};
|
|
};
|
|
|
|
template<>
|
|
struct if_impl<false>
|
|
{
|
|
template< typename T1, typename T2 > struct result_
|
|
{
|
|
typedef T2 type;
|
|
};
|
|
};
|
|
|
|
} // namespace aux
|
|
|
|
template<
|
|
bool C_
|
|
, typename T1
|
|
, typename T2
|
|
>
|
|
struct if_c
|
|
{
|
|
typedef typename aux::if_impl< C_ >
|
|
::template result_<T1,T2>::type type;
|
|
};
|
|
|
|
// (almost) copy & paste in order to save one more
|
|
// recursively nested template instantiation to user
|
|
template<
|
|
typename BOOST_MPL_AUX_NA_PARAM(C_)
|
|
, typename BOOST_MPL_AUX_NA_PARAM(T1)
|
|
, typename BOOST_MPL_AUX_NA_PARAM(T2)
|
|
>
|
|
struct if_
|
|
{
|
|
enum { msvc_wknd_ = BOOST_MPL_AUX_MSVC_VALUE_WKND(C_)::value };
|
|
|
|
typedef typename aux::if_impl< BOOST_MPL_AUX_STATIC_CAST(bool, msvc_wknd_) >
|
|
::template result_<T1,T2>::type type;
|
|
|
|
BOOST_MPL_AUX_LAMBDA_SUPPORT(3,if_,(C_,T1,T2))
|
|
};
|
|
|
|
#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
|
|
|
BOOST_MPL_AUX_NA_SPEC(3, if_)
|
|
|
|
}}
|
|
|
|
#endif // BOOST_MPL_IF_HPP_INCLUDED
|