boost/container/detail/variadic_templates_tools.hpp
//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2008-2013. 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.
//
//////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_CONTAINER_DETAIL_VARIADIC_TEMPLATES_TOOLS_HPP
#define BOOST_CONTAINER_DETAIL_VARIADIC_TEMPLATES_TOOLS_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/type_traits.hpp>
#include <cstddef> //std::size_t
namespace boost {
namespace container {
namespace container_detail {
template<typename... Values>
class tuple;
template<> class tuple<>
{};
template<typename Head, typename... Tail>
class tuple<Head, Tail...>
: private tuple<Tail...>
{
typedef tuple<Tail...> inherited;
public:
tuple() { }
// implicit copy-constructor is okay
// Construct tuple from separate arguments.
tuple(typename add_const_reference<Head>::type v,
typename add_const_reference<Tail>::type... vtail)
: inherited(vtail...), m_head(v)
{}
// Construct tuple from another tuple.
template<typename... VValues>
tuple(const tuple<VValues...>& other)
: m_head(other.head()), inherited(other.tail())
{}
template<typename... VValues>
tuple& operator=(const tuple<VValues...>& other)
{
m_head = other.head();
tail() = other.tail();
return this;
}
typename add_reference<Head>::type head() { return m_head; }
typename add_reference<const Head>::type head() const { return m_head; }
inherited& tail() { return *this; }
const inherited& tail() const { return *this; }
protected:
Head m_head;
};
template<typename... Values>
tuple<Values&&...> tie_forward(Values&&... values)
{ return tuple<Values&&...>(values...); }
template<int I, typename Tuple>
struct tuple_element;
template<int I, typename Head, typename... Tail>
struct tuple_element<I, tuple<Head, Tail...> >
{
typedef typename tuple_element<I-1, tuple<Tail...> >::type type;
};
template<typename Head, typename... Tail>
struct tuple_element<0, tuple<Head, Tail...> >
{
typedef Head type;
};
template<int I, typename Tuple>
class get_impl;
template<int I, typename Head, typename... Values>
class get_impl<I, tuple<Head, Values...> >
{
typedef typename tuple_element<I-1, tuple<Values...> >::type Element;
typedef get_impl<I-1, tuple<Values...> > Next;
public:
typedef typename add_reference<Element>::type type;
typedef typename add_const_reference<Element>::type const_type;
static type get(tuple<Head, Values...>& t) { return Next::get(t.tail()); }
static const_type get(const tuple<Head, Values...>& t) { return Next::get(t.tail()); }
};
template<typename Head, typename... Values>
class get_impl<0, tuple<Head, Values...> >
{
public:
typedef typename add_reference<Head>::type type;
typedef typename add_const_reference<Head>::type const_type;
static type get(tuple<Head, Values...>& t) { return t.head(); }
static const_type get(const tuple<Head, Values...>& t){ return t.head(); }
};
template<int I, typename... Values>
typename get_impl<I, tuple<Values...> >::type get(tuple<Values...>& t)
{ return get_impl<I, tuple<Values...> >::get(t); }
template<int I, typename... Values>
typename get_impl<I, tuple<Values...> >::const_type get(const tuple<Values...>& t)
{ return get_impl<I, tuple<Values...> >::get(t); }
////////////////////////////////////////////////////
// Builds an index_tuple<0, 1, 2, ..., Num-1>, that will
// be used to "unpack" into comma-separated values
// in a function call.
////////////////////////////////////////////////////
template<int... Indexes>
struct index_tuple{};
template<std::size_t Num, typename Tuple = index_tuple<> >
struct build_number_seq;
template<std::size_t Num, int... Indexes>
struct build_number_seq<Num, index_tuple<Indexes...> >
: build_number_seq<Num - 1, index_tuple<Indexes..., sizeof...(Indexes)> >
{};
template<int... Indexes>
struct build_number_seq<0, index_tuple<Indexes...> >
{ typedef index_tuple<Indexes...> type; };
}}} //namespace boost { namespace container { namespace container_detail {
#include <boost/container/detail/config_end.hpp>
#endif //#ifndef BOOST_CONTAINER_DETAIL_VARIADIC_TEMPLATES_TOOLS_HPP