90 lines
2.1 KiB
C++
90 lines
2.1 KiB
C++
////////////////////////////////////////////////////////////////////
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//
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// Copyright Vicente J. Botet Escriba 2010
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/mpl for documentation.
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//
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////////////////////////////////////////////////////////////////////
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#ifndef BOOST_MPL_SIGN_HPP_INCLUDED
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#define BOOST_MPL_SIGN_HPP_INCLUDED
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#include <boost/mpl/integral_c.hpp>
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#include <boost/mpl/aux_/na_spec.hpp>
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#include <boost/mpl/aux_/lambda_support.hpp>
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#include <boost/mpl/aux_/config/eti.hpp>
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#include <boost/mpl/aux_/config/integral.hpp>
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#include <boost/mpl/aux_/config/static_constant.hpp>
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#if !defined(BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2) \
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&& !defined(BOOST_MPL_PREPROCESSING_MODE) \
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&& ( defined(BOOST_MSVC) \
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|| BOOST_WORKAROUND(__EDG_VERSION__, <= 238) \
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)
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# define BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2
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#endif
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namespace boost { namespace mpl {
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template< typename Tag > struct sign_impl;
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template< typename T > struct sign_tag
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{
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typedef typename T::tag type;
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};
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template<
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typename BOOST_MPL_AUX_NA_PARAM(N)
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>
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struct sign
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: sign_impl<
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typename sign_tag<N>::type
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>::template apply<N>::type
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{
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BOOST_MPL_AUX_LAMBDA_SUPPORT(1, sign, (N))
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};
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BOOST_MPL_AUX_NA_SPEC(1, sign)
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template<
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typename T
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, T n1
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>
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struct sign_c
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: sign<integral_c<T,n1> >
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{
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};
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#if defined(BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2)
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namespace aux {
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template< typename T, T n > struct sign_wknd
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{
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BOOST_STATIC_CONSTANT(T, value = (n == 0 ? 0 : (n < 0 ? -1 : 1)));
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typedef integral_c<T,value> type;
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};
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}
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#endif
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template<>
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struct sign_impl<integral_c_tag>
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{
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#if defined(BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2)
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template< typename N > struct apply
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: aux::sign_wknd< typename N::value_type, N::value >
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#else
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template< typename N > struct apply
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: integral_c< typename N::value_type, (N::value == 0 ? 0 : (N::value < 0 ? -1 : 1)) >
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#endif
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{
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};
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};
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}}
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#endif // BOOST_MPL_SIGN_HPP_INCLUDED
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