You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and dots ('.'), can be up to 35 characters long. Letters must be lowercase.
128 lines
4.0 KiB
128 lines
4.0 KiB
// 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) 2007-2008 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) |
|
|
|
/// \file |
|
/// \brief base unit (meter, kg, sec...). |
|
/// \details base unit definition registration. |
|
|
|
#ifndef BOOST_UNITS_BASE_UNIT_HPP |
|
#define BOOST_UNITS_BASE_UNIT_HPP |
|
|
|
#include <boost/units/config.hpp> |
|
#include <boost/units/heterogeneous_system.hpp> |
|
#include <boost/units/static_rational.hpp> |
|
#include <boost/units/units_fwd.hpp> |
|
#include <boost/units/unit.hpp> |
|
#include <boost/units/detail/dimension_list.hpp> |
|
#include <boost/units/detail/ordinal.hpp> |
|
#include <boost/units/detail/prevent_redefinition.hpp> |
|
|
|
namespace boost { |
|
|
|
namespace units { |
|
|
|
/// This must be in namespace boost::units so that ADL |
|
/// will work with friend functions defined inline. |
|
/// Base dimensions and base units are independent. |
|
/// INTERNAL ONLY |
|
template<long N> struct base_unit_ordinal { }; |
|
|
|
/// INTERNAL ONLY |
|
template<class T, long N> struct base_unit_pair { }; |
|
|
|
/// INTERNAL ONLY |
|
template<class T, long N> |
|
struct check_base_unit { |
|
enum { |
|
value = |
|
sizeof(boost_units_unit_is_registered(units::base_unit_ordinal<N>())) == sizeof(detail::yes) && |
|
sizeof(boost_units_unit_is_registered(units::base_unit_pair<T, N>())) != sizeof(detail::yes) |
|
}; |
|
}; |
|
|
|
/// Defines a base unit. To define a unit you need to provide |
|
/// the derived class (CRTP), a dimension list and a unique integer. |
|
/// @code |
|
/// struct my_unit : boost::units::base_unit<my_unit, length_dimension, 1> {}; |
|
/// @endcode |
|
/// It is designed so that you will get an error message if you try |
|
/// to use the same value in multiple definitions. |
|
template<class Derived, |
|
class Dim, |
|
long N |
|
#if !defined(BOOST_UNITS_DOXYGEN) && !defined(__BORLANDC__) |
|
, |
|
class = typename detail::ordinal_has_already_been_defined< |
|
check_base_unit<Derived, N>::value |
|
>::type |
|
#endif |
|
> |
|
class base_unit : |
|
public ordinal<N> |
|
{ |
|
public: |
|
/// INTERNAL ONLY |
|
typedef void boost_units_is_base_unit_type; |
|
/// INTERNAL ONLY |
|
typedef base_unit this_type; |
|
/// The dimensions of this base unit. |
|
typedef Dim dimension_type; |
|
|
|
/// Provided for mpl compatability. |
|
typedef Derived type; |
|
|
|
/// The unit corresponding to this base unit. |
|
#ifndef BOOST_UNITS_DOXYGEN |
|
typedef unit< |
|
Dim, |
|
heterogeneous_system< |
|
heterogeneous_system_impl< |
|
list< |
|
heterogeneous_system_dim<Derived,static_rational<1> >, |
|
dimensionless_type |
|
>, |
|
Dim, |
|
no_scale |
|
> |
|
> |
|
> unit_type; |
|
#else |
|
typedef detail::unspecified unit_type; |
|
#endif |
|
|
|
private: |
|
/// Check for C++0x. In C++0x, we have to have identical |
|
/// arguments but a different return type to trigger an |
|
/// error. Note that this is only needed for clang as |
|
/// check_base_unit will trigger an error earlier |
|
/// for compilers with less strict name lookup. |
|
/// INTERNAL ONLY |
|
friend Derived* |
|
check_double_register(const units::base_unit_ordinal<N>&) |
|
{ return(0); } |
|
|
|
/// Register this ordinal |
|
/// INTERNAL ONLY |
|
friend detail::yes |
|
boost_units_unit_is_registered(const units::base_unit_ordinal<N>&) |
|
{ detail::yes result; return(result); } |
|
|
|
/// But make sure we can identify the current instantiation! |
|
/// INTERNAL ONLY |
|
friend detail::yes |
|
boost_units_unit_is_registered(const units::base_unit_pair<Derived, N>&) |
|
{ detail::yes result; return(result); } |
|
}; |
|
|
|
} // namespace units |
|
|
|
} // namespace boost |
|
|
|
#endif // BOOST_UNITS_BASE_UNIT_HPP
|
|
|