ext-boost/boost/ratio/detail/mpl/sign.hpp
2019-08-24 15:39:04 +02:00

90 lines
2.1 KiB
C++

////////////////////////////////////////////////////////////////////
//
// Copyright Vicente J. Botet Escriba 2010
//
// 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/mpl for documentation.
//
////////////////////////////////////////////////////////////////////
#ifndef BOOST_MPL_SIGN_HPP_INCLUDED
#define BOOST_MPL_SIGN_HPP_INCLUDED
#include <boost/mpl/integral_c.hpp>
#include <boost/mpl/aux_/na_spec.hpp>
#include <boost/mpl/aux_/lambda_support.hpp>
#include <boost/mpl/aux_/config/integral.hpp>
#include <boost/mpl/aux_/config/static_constant.hpp>
#if !defined(BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2) \
&& !defined(BOOST_MPL_PREPROCESSING_MODE) \
&& !defined(__CUDACC__) \
&& ( defined(BOOST_MSVC) \
|| BOOST_WORKAROUND(__EDG_VERSION__, <= 238) \
)
# define BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2
#endif
namespace boost { namespace mpl {
template< typename Tag > struct sign_impl;
template< typename T > struct sign_tag
{
typedef typename T::tag type;
};
template<
typename BOOST_MPL_AUX_NA_PARAM(N)
>
struct sign
: sign_impl<
typename sign_tag<N>::type
>::template apply<N>::type
{
BOOST_MPL_AUX_LAMBDA_SUPPORT(1, sign, (N))
};
BOOST_MPL_AUX_NA_SPEC(1, sign)
template<
typename T
, T n1
>
struct sign_c
: sign<integral_c<T,n1> >
{
};
#if defined(BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2)
namespace aux {
template< typename T, T n > struct sign_wknd
{
BOOST_STATIC_CONSTANT(T, value = (n == 0 ? 0 : (n < 0 ? -1 : 1)));
typedef integral_c<T,value> type;
};
}
#endif
template<>
struct sign_impl<integral_c_tag>
{
#if defined(BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2)
template< typename N > struct apply
: aux::sign_wknd< typename N::value_type, N::value >
#else
template< typename N > struct apply
: integral_c< typename N::value_type, (N::value == 0 ? 0 : (N::value < 0 ? -1 : 1)) >
#endif
{
};
};
}}
#endif // BOOST_MPL_SIGN_HPP_INCLUDED