// (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. | |
#ifndef BOOST_IOSTREAMS_DETAIL_WRAP_UNWRAP_HPP_INCLUDED | |
#define BOOST_IOSTREAMS_DETAIL_WRAP_UNWRAP_HPP_INCLUDED | |
#if defined(_MSC_VER) && (_MSC_VER >= 1020) | |
# pragma once | |
#endif | |
#include <boost/config.hpp> // SFINAE, MSVC. | |
#include <boost/detail/workaround.hpp> | |
#include <boost/iostreams/detail/enable_if_stream.hpp> | |
#include <boost/iostreams/traits_fwd.hpp> // is_std_io. | |
#include <boost/mpl/bool.hpp> | |
#include <boost/mpl/identity.hpp> | |
#include <boost/mpl/eval_if.hpp> | |
#include <boost/mpl/if.hpp> | |
#include <boost/ref.hpp> | |
namespace boost { namespace iostreams { namespace detail { | |
//------------------Definition of wrap/unwrap traits--------------------------// | |
template<typename T> | |
struct wrapped_type | |
: mpl::if_<is_std_io<T>, reference_wrapper<T>, T> | |
{ }; | |
template<typename T> | |
struct unwrapped_type | |
: unwrap_reference<T> | |
{ }; | |
template<typename T> | |
struct unwrap_ios | |
: mpl::eval_if< | |
is_std_io<T>, | |
unwrap_reference<T>, | |
mpl::identity<T> | |
> | |
{ }; | |
//------------------Definition of wrap----------------------------------------// | |
#ifndef BOOST_NO_SFINAE //----------------------------------------------------// | |
template<typename T> | |
inline T wrap(const T& t BOOST_IOSTREAMS_DISABLE_IF_STREAM(T)) | |
{ return t; } | |
template<typename T> | |
inline typename wrapped_type<T>::type | |
wrap(T& t BOOST_IOSTREAMS_ENABLE_IF_STREAM(T)) { return boost::ref(t); } | |
#else // #ifndef BOOST_NO_SFINAE //-------------------------------------------// | |
template<typename T> | |
inline typename wrapped_type<T>::type // BCC 5.x needs namespace qualification. | |
wrap_impl(const T& t, mpl::true_) { return boost::ref(const_cast<T&>(t)); } | |
template<typename T> | |
inline typename wrapped_type<T>::type // BCC 5.x needs namespace qualification. | |
wrap_impl(T& t, mpl::true_) { return boost::ref(t); } | |
template<typename T> | |
inline typename wrapped_type<T>::type | |
wrap_impl(const T& t, mpl::false_) { return t; } | |
template<typename T> | |
inline typename wrapped_type<T>::type | |
wrap_impl(T& t, mpl::false_) { return t; } | |
template<typename T> | |
inline typename wrapped_type<T>::type | |
wrap(const T& t) { return wrap_impl(t, is_std_io<T>()); } | |
template<typename T> | |
inline typename wrapped_type<T>::type | |
wrap(T& t) { return wrap_impl(t, is_std_io<T>()); } | |
#endif // #ifndef BOOST_NO_SFINAE //------------------------------------------// | |
//------------------Definition of unwrap--------------------------------------// | |
#if !BOOST_WORKAROUND(BOOST_MSVC, < 1310) //----------------------------------// | |
template<typename T> | |
typename unwrapped_type<T>::type& | |
unwrap(const reference_wrapper<T>& ref) { return ref.get(); } | |
template<typename T> | |
typename unwrapped_type<T>::type& unwrap(T& t) { return t; } | |
template<typename T> | |
const typename unwrapped_type<T>::type& unwrap(const T& t) { return t; } | |
#else // #if !BOOST_WORKAROUND(BOOST_MSVC, < 1310) //-------------------------// | |
// Since unwrap is a potential bottleneck, we avoid runtime tag dispatch. | |
template<bool IsRefWrap> | |
struct unwrap_impl; | |
template<> | |
struct unwrap_impl<true> { | |
template<typename T> | |
static typename unwrapped_type<T>::type& unwrap(const T& t) | |
{ return t.get(); } | |
}; | |
template<> | |
struct unwrap_impl<false> { | |
template<typename T> | |
static typename unwrapped_type<T>::type& unwrap(const T& t) | |
{ return const_cast<T&>(t); } | |
}; | |
template<typename T> | |
typename unwrapped_type<T>::type& | |
unwrap(const T& t) | |
{ return unwrap_impl<is_reference_wrapper<T>::value>::unwrap(t); } | |
#endif // #if !BOOST_WORKAROUND(BOOST_MSVC, < 1310) //------------------------// | |
} } } // End namespaces detail, iostreams, boost. | |
#endif // #ifndef BOOST_IOSTREAMS_DETAIL_WRAP_UNWRAP_HPP_INCLUDED |