ecency-mobile/ios/Pods/boost-for-react-native/boost/units/base_dimension.hpp

108 lines
3.7 KiB
C++

// 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 dimensions (mass, length, time...).
/// \details base dimension definition registration.
#ifndef BOOST_UNITS_BASE_DIMENSION_HPP
#define BOOST_UNITS_BASE_DIMENSION_HPP
#include <boost/units/config.hpp>
#include <boost/units/dim.hpp>
#include <boost/units/static_rational.hpp>
#include <boost/units/units_fwd.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.
/// INTERNAL ONLY
template<long N> struct base_dimension_ordinal { };
/// INTERNAL ONLY
template<class T, long N> struct base_dimension_pair { };
/// INTERNAL ONLY
template<class T, long N>
struct check_base_dimension {
enum {
value =
sizeof(boost_units_is_registered(units::base_dimension_ordinal<N>())) == sizeof(detail::yes) &&
sizeof(boost_units_is_registered(units::base_dimension_pair<T, N>())) != sizeof(detail::yes)
};
};
/// Defines a base dimension. To define a dimension you need to provide
/// the derived class (CRTP) and a unique integer.
/// @code
/// struct my_dimension : boost::units::base_dimension<my_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,
long N
#if !defined(BOOST_UNITS_DOXYGEN) && !defined(__BORLANDC__)
,
class = typename detail::ordinal_has_already_been_defined<
check_base_dimension<Derived, N>::value
>::type
#endif
>
class base_dimension :
public ordinal<N>
{
public:
/// INTERNAL ONLY
typedef base_dimension this_type;
/// A convenience typedef. Equivalent to boost::units::derived_dimension<Derived,1>::type.
#ifndef BOOST_UNITS_DOXYGEN
typedef list<dim<Derived,static_rational<1> >, dimensionless_type> dimension_type;
#else
typedef detail::unspecified dimension_type;
#endif
/// Provided for mpl compatability.
typedef Derived type;
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_dimension will trigger an error earlier
/// for compilers with less strict name lookup.
/// INTERNAL ONLY
friend Derived*
check_double_register(const units::base_dimension_ordinal<N>&)
{ return(0); }
/// Register this ordinal
/// INTERNAL ONLY
friend detail::yes
boost_units_is_registered(const units::base_dimension_ordinal<N>&)
{ detail::yes result; return(result); }
/// But make sure we can identify the current instantiation!
/// INTERNAL ONLY
friend detail::yes
boost_units_is_registered(const units::base_dimension_pair<Derived, N>&)
{ detail::yes result; return(result); }
};
} // namespace units
} // namespace boost
#endif // BOOST_UNITS_BASE_DIMENSION_HPP