// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) | |
// (C) Copyright 2003-2007 Jonathan Turkanis | |
// 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/iostreams for documentation. | |
// Contains the definition of the class template access_control, which | |
// allows the type of inheritance from a provided base class to be specified | |
// using a template parameter. | |
#ifndef BOOST_IOSTREAMS_ACCESS_CONTROL_HPP_INCLUDED | |
#define BOOST_IOSTREAMS_ACCESS_CONTROL_HPP_INCLUDED | |
#if defined(_MSC_VER) && (_MSC_VER >= 1020) | |
# pragma once | |
#endif | |
#include <boost/iostreams/detail/select.hpp> | |
#include <boost/mpl/identity.hpp> | |
#include <boost/type_traits/is_same.hpp> | |
namespace boost { namespace iostreams { | |
struct protected_ { }; // Represents protected inheritance. | |
struct public_ { }; // Represents public inheritance. | |
namespace detail { | |
// Implements protected inheritance. | |
template<typename U> | |
struct prot_ : protected U | |
{ | |
prot_() { } | |
template<typename V> prot_(V v) : U(v) { } | |
}; | |
// Implements public inheritance. | |
template<typename U> struct pub_ : public U { | |
pub_() { } | |
template<typename V> pub_(V v) : U(v) { } | |
}; | |
// | |
// Used to deduce the base type for the template access_control. | |
// | |
template<typename T, typename Access> | |
struct access_control_base { | |
typedef int bad_access_specifier; | |
typedef typename | |
iostreams::select< // Disambiguation for Tru64 | |
::boost::is_same< | |
Access, protected_ | |
>, prot_<T>, | |
::boost::is_same< | |
Access, public_ | |
>, pub_<T>, | |
else_, bad_access_specifier | |
>::type type; | |
}; | |
} // End namespace detail. | |
// | |
// Template name: access_control. | |
// Description: Allows the type of inheritance from a provided base class | |
// to be specified using an int template parameter. | |
// Template parameters: | |
// Base - The class from which to inherit (indirectly.) | |
// Access - The type of access desired. Must be one of the | |
// values access_base::prot or access_base::pub. | |
// | |
template< typename T, typename Access, | |
typename Base = // VC6 workaraound (Compiler Error C2516) | |
typename detail::access_control_base<T, Access>::type > | |
struct access_control : public Base { | |
access_control() { } | |
template<typename U> explicit access_control(U u) : Base(u) { } | |
}; | |
//----------------------------------------------------------------------------// | |
} } // End namespaces iostreams, boost. | |
#endif // #ifndef BOOST_IOSTREAMS_ACCESS_CONTROL_HPP_INCLUDED |