// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
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// (C) Copyright 2003-2007 Jonathan Turkanis
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
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// See http://www.boost.org/libs/iostreams for documentation.
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// Contains the definition of the class template access_control, which
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// allows the type of inheritance from a provided base class to be specified
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// using a template parameter.
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#ifndef BOOST_IOSTREAMS_ACCESS_CONTROL_HPP_INCLUDED
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#define BOOST_IOSTREAMS_ACCESS_CONTROL_HPP_INCLUDED
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#if defined(_MSC_VER)
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# pragma once
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#endif
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#include <boost/iostreams/detail/select.hpp>
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#include <boost/mpl/identity.hpp>
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#include <boost/type_traits/is_same.hpp>
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namespace boost { namespace iostreams {
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struct protected_ { }; // Represents protected inheritance.
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struct public_ { }; // Represents public inheritance.
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namespace detail {
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// Implements protected inheritance.
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template<typename U>
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struct prot_ : protected U
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{
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prot_() { }
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template<typename V> prot_(V v) : U(v) { }
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};
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// Implements public inheritance.
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template<typename U> struct pub_ : public U {
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pub_() { }
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template<typename V> pub_(V v) : U(v) { }
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};
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//
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// Used to deduce the base type for the template access_control.
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//
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template<typename T, typename Access>
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struct access_control_base {
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typedef int bad_access_specifier;
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typedef typename
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iostreams::select< // Disambiguation for Tru64
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::boost::is_same<
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Access, protected_
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>, prot_<T>,
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::boost::is_same<
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Access, public_
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>, pub_<T>,
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else_, bad_access_specifier
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>::type type;
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};
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} // End namespace detail.
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//
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// Template name: access_control.
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// Description: Allows the type of inheritance from a provided base class
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// to be specified using an int template parameter.
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// Template parameters:
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// Base - The class from which to inherit (indirectly.)
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// Access - The type of access desired. Must be one of the
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// values access_base::prot or access_base::pub.
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//
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template< typename T, typename Access,
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typename Base = // VC6 workaraound (Compiler Error C2516)
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typename detail::access_control_base<T, Access>::type >
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struct access_control : public Base {
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access_control() { }
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template<typename U> explicit access_control(U u) : Base(u) { }
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};
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//----------------------------------------------------------------------------//
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} } // End namespaces iostreams, boost.
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#endif // #ifndef BOOST_IOSTREAMS_ACCESS_CONTROL_HPP_INCLUDED
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