boost/container/detail/version_type.hpp
//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2013. 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/container for documentation.
//
//////////////////////////////////////////////////////////////////////////////
//
// This code comes from N1953 document by Howard E. Hinnant
//
//////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_CONTAINER_DETAIL_VERSION_TYPE_HPP
#define BOOST_CONTAINER_DETAIL_VERSION_TYPE_HPP
#ifndef BOOST_CONFIG_HPP
# include <boost/config.hpp>
#endif
#if defined(BOOST_HAS_PRAGMA_ONCE)
# pragma once
#endif
#include <boost/container/detail/config_begin.hpp>
#include <boost/container/detail/workaround.hpp>
#include <boost/container/detail/mpl.hpp>
#include <boost/container/detail/type_traits.hpp>
namespace boost{
namespace container {
namespace container_detail {
template <class T, unsigned V>
struct version_type
: public container_detail::integral_constant<unsigned, V>
{
typedef T type;
version_type(const version_type<T, 0>&);
};
namespace impl{
template <class T,
bool = container_detail::is_convertible<version_type<T, 0>, typename T::version>::value>
struct extract_version
{
static const unsigned value = 1;
};
template <class T>
struct extract_version<T, true>
{
static const unsigned value = T::version::value;
};
template <class T>
struct has_version
{
private:
struct two {char _[2];};
template <class U> static two test(...);
template <class U> static char test(const typename U::version*);
public:
static const bool value = sizeof(test<T>(0)) == 1;
void dummy(){}
};
template <class T, bool = has_version<T>::value>
struct version
{
static const unsigned value = 1;
};
template <class T>
struct version<T, true>
{
static const unsigned value = extract_version<T>::value;
};
} //namespace impl
template <class T>
struct version
: public container_detail::integral_constant<unsigned, impl::version<T>::value>
{};
template<class T, unsigned N>
struct is_version
{
static const bool value =
is_same< typename version<T>::type, integral_constant<unsigned, N> >::value;
};
} //namespace container_detail {
typedef container_detail::integral_constant<unsigned, 0> version_0;
typedef container_detail::integral_constant<unsigned, 1> version_1;
typedef container_detail::integral_constant<unsigned, 2> version_2;
} //namespace container {
} //namespace boost{
#include <boost/container/detail/config_end.hpp>
#endif //#define BOOST_CONTAINER_DETAIL_VERSION_TYPE_HPP