64 lines
2.3 KiB
C++
64 lines
2.3 KiB
C++
///////////////////////////////////////////////////////////////////////////////
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// Copyright 2015 John Maddock. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_MP_IS_BACKEND_HPP
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#define BOOST_MP_IS_BACKEND_HPP
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#include <boost/mpl/has_xxx.hpp>
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#include <boost/type_traits/conditional.hpp>
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#include <boost/type_traits/is_convertible.hpp>
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#include <boost/multiprecision/detail/number_base.hpp>
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namespace boost{ namespace multiprecision{ namespace detail{
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BOOST_MPL_HAS_XXX_TRAIT_DEF(signed_types);
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BOOST_MPL_HAS_XXX_TRAIT_DEF(unsigned_types);
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BOOST_MPL_HAS_XXX_TRAIT_DEF(float_types);
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template <class T>
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struct is_backend
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{
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static const bool value = has_signed_types<T>::value && has_unsigned_types<T>::value && has_float_types<T>::value;
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};
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template <class Backend>
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struct other_backend
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{
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typedef typename boost::conditional<
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boost::is_same<number<Backend>, number<Backend, et_on> >::value,
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number<Backend, et_off>, number<Backend, et_on> >::type type;
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};
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template <class B, class V>
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struct number_from_backend
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{
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typedef typename boost::conditional <
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boost::is_convertible<V, number<B> >::value,
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number<B>,
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typename other_backend<B>::type > ::type type;
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};
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template <bool b, class T, class U>
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struct is_first_backend_imp{ static const bool value = false; };
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template <class T, class U>
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struct is_first_backend_imp<true, T, U>{ static const bool value = is_convertible<U, number<T, et_on> >::value || is_convertible<U, number<T, et_off> >::value; };
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template <class T, class U>
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struct is_first_backend : is_first_backend_imp<is_backend<T>::value, T, U> {};
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template <bool b, class T, class U>
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struct is_second_backend_imp{ static const bool value = false; };
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template <class T, class U>
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struct is_second_backend_imp<true, T, U>{ static const bool value = (is_convertible<T, number<U, et_on> >::value || is_convertible<T, number<U, et_off> >::value) && !is_first_backend<T, U>::value; };
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template <class T, class U>
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struct is_second_backend : is_second_backend_imp<is_backend<U>::value, T, U> {};
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}
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}
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}
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#endif // BOOST_MP_IS_BACKEND_HPP
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