85 lines
2.0 KiB
Plaintext
85 lines
2.0 KiB
Plaintext
|
// Boost.Units - A C++ library for zero-overhead dimensional analysis and
|
||
|
|
// unit/quantity manipulation and conversion
|
||
|
|
//
|
||
|
|
// Copyright (C) 2003-2008 Matthias Christian Schabel
|
||
|
|
// Copyright (C) 2008 Steven Watanabe
|
||
|
|
//
|
||
|
|
// 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_UNITS_DETAIL_PUSH_FRONT_OR_ADD_HPP
|
||
|
|
#define BOOST_UNITS_DETAIL_PUSH_FRONT_OR_ADD_HPP
|
||
|
|
|
||
|
|
#include <boost/mpl/plus.hpp>
|
||
|
|
#include <boost/mpl/front.hpp>
|
||
|
|
#include <boost/mpl/push_front.hpp>
|
||
|
|
#include <boost/mpl/pop_front.hpp>
|
||
|
|
#include <boost/type_traits/is_same.hpp>
|
||
|
|
|
||
|
|
#include <boost/units/units_fwd.hpp>
|
||
|
|
#include <boost/units/detail/push_front_if.hpp>
|
||
|
|
|
||
|
|
namespace boost {
|
||
|
|
|
||
|
|
namespace units {
|
||
|
|
|
||
|
|
template<class Item, class Next>
|
||
|
|
struct list;
|
||
|
|
|
||
|
|
namespace detail {
|
||
|
|
|
||
|
|
template<class T>
|
||
|
|
struct is_empty_dim;
|
||
|
|
|
||
|
|
/// add an instantiation of dim to Sequence.
|
||
|
|
template<bool>
|
||
|
|
struct push_front_or_add_impl;
|
||
|
|
|
||
|
|
template<>
|
||
|
|
struct push_front_or_add_impl<true>
|
||
|
|
{
|
||
|
|
template<typename Sequence, typename T>
|
||
|
|
struct apply
|
||
|
|
{
|
||
|
|
typedef typename mpl::plus<T, typename Sequence::item>::type item;
|
||
|
|
typedef typename push_front_if<!is_empty_dim<item>::value>::template apply<
|
||
|
|
typename Sequence::next,
|
||
|
|
item
|
||
|
|
> type;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
template<>
|
||
|
|
struct push_front_or_add_impl<false>
|
||
|
|
{
|
||
|
|
template<typename Sequence, typename T>
|
||
|
|
struct apply
|
||
|
|
{
|
||
|
|
typedef list<T, Sequence> type;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
template<typename Sequence, typename T>
|
||
|
|
struct push_front_or_add
|
||
|
|
{
|
||
|
|
typedef typename push_front_or_add_impl<boost::is_same<typename T::tag_type, typename Sequence::item::tag_type>::value>::template apply<
|
||
|
|
Sequence,
|
||
|
|
T
|
||
|
|
>::type type;
|
||
|
|
};
|
||
|
|
|
||
|
|
template<typename T>
|
||
|
|
struct push_front_or_add<dimensionless_type, T>
|
||
|
|
{
|
||
|
|
typedef list<T, dimensionless_type> type;
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace detail
|
||
|
|
|
||
|
|
} // namespace units
|
||
|
|
|
||
|
|
} // namespace boost
|
||
|
|
|
||
|
|
#endif
|