boost/variant/detail/backup_holder.hpp
//-----------------------------------------------------------------------------
// boost variant/detail/backup_holder.hpp header file
// See http://www.boost.org for updates, documentation, and revision history.
//-----------------------------------------------------------------------------
//
// Copyright (c) 2003
// Eric Friedman
//
// 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)
#ifndef BOOST_VARIANT_DETAIL_BACKUP_HOLDER_HPP
#define BOOST_VARIANT_DETAIL_BACKUP_HOLDER_HPP
#include "boost/assert.hpp"
namespace boost {
namespace detail { namespace variant {
template <typename T>
class backup_holder
{
private: // representation
T* backup_;
public: // structors
~backup_holder()
{
delete backup_;
}
explicit backup_holder(T* backup)
: backup_(backup)
{
}
backup_holder(const backup_holder&);
public: // modifiers
backup_holder& operator=(const backup_holder& rhs)
{
*backup_ = rhs.get();
return *this;
}
backup_holder& operator=(const T& rhs)
{
*backup_ = rhs;
return *this;
}
void swap(backup_holder& rhs)
{
T* tmp = rhs.backup_;
rhs.backup_ = this->backup_;
this->backup_ = tmp;
}
public: // queries
T& get()
{
return *backup_;
}
const T& get() const
{
return *backup_;
}
};
template <typename T>
backup_holder<T>::backup_holder(const backup_holder&)
: backup_(0)
{
// not intended for copy, but do not want to prohibit syntactically
BOOST_ASSERT(false);
}
template <typename T>
void swap(backup_holder<T>& lhs, backup_holder<T>& rhs)
{
lhs.swap(rhs);
}
}} // namespace detail::variant
} // namespace boost
#endif // BOOST_VARIANT_DETAIL_BACKUP_HOLDER_HPP