sp_convertible.hpp

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#ifndef BOOST_SMART_PTR_DETAIL_SP_CONVERTIBLE_HPP_INCLUDED
#define BOOST_SMART_PTR_DETAIL_SP_CONVERTIBLE_HPP_INCLUDED
 
// MS compatible compilers support #pragma once
 
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif
 
//  detail/sp_convertible.hpp
//
//  Copyright 2008 Peter Dimov
//
//  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
 
#include <boost/config.hpp>
#include <cstddef>
 
#if !defined( BOOST_SP_NO_SP_CONVERTIBLE ) && defined( BOOST_NO_SFINAE )
# define BOOST_SP_NO_SP_CONVERTIBLE
#endif
 
#if !defined( BOOST_SP_NO_SP_CONVERTIBLE ) && defined( __GNUC__ ) && ( __GNUC__ * 100 + __GNUC_MINOR__ < 303 )
# define BOOST_SP_NO_SP_CONVERTIBLE
#endif
 
#if !defined( BOOST_SP_NO_SP_CONVERTIBLE ) && defined( __BORLANDC__ ) && ( __BORLANDC__ < 0x630 )
# define BOOST_SP_NO_SP_CONVERTIBLE
#endif
 
#if !defined( BOOST_SP_NO_SP_CONVERTIBLE )
 
namespace boost
{
 
namespace detail
{
 
template< class Y, class T > struct sp_convertible
{
    typedef char (&yes) [1];
    typedef char (&no)  [2];
 
    static yes f( T* );
    static no  f( ... );
 
    enum _vt { value = sizeof( (f)( static_cast<Y*>(0) ) ) == sizeof(yes) };
};
 
template< class Y, class T > struct sp_convertible< Y, T[] >
{
    enum _vt { value = false };
};
 
template< class Y, class T > struct sp_convertible< Y[], T[] >
{
    enum _vt { value = sp_convertible< Y[1], T[1] >::value };
};
 
template< class Y, std::size_t N, class T > struct sp_convertible< Y[N], T[] >
{
    enum _vt { value = sp_convertible< Y[1], T[1] >::value };
};
 
struct sp_empty
{
};
 
template< bool > struct sp_enable_if_convertible_impl;
 
template<> struct sp_enable_if_convertible_impl<true>
{
    typedef sp_empty type;
};
 
template<> struct sp_enable_if_convertible_impl<false>
{
};
 
template< class Y, class T > struct sp_enable_if_convertible: public sp_enable_if_convertible_impl< sp_convertible< Y, T >::value >
{
};
 
} // namespace detail
 
} // namespace boost
 
#endif // !defined( BOOST_SP_NO_SP_CONVERTIBLE )
 
#endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_CONVERTIBLE_HPP_INCLUDED