| 1 | /////////////////////////////////////////////////////////////////////////////// |
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| 2 | // Copyright Vicente J. Botet Escriba 2009-2011 |
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| 3 | // Copyright 2012 John Maddock. Distributed under the Boost |
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| 4 | // Software License, Version 1.0. (See accompanying file |
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| 5 | // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
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| 6 | |
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| 7 | #ifndef BOOST_MP_EXPLICIT_CONVERSION_HPP |
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| 8 | #define BOOST_MP_EXPLICIT_CONVERSION_HPP |
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| 9 | |
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| 10 | #include <type_traits> |
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| 11 | #include <boost/multiprecision/detail/standalone_config.hpp> |
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| 12 | #include <boost/multiprecision/detail/number_base.hpp> // number_category |
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| 13 | |
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| 14 | namespace boost { |
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| 15 | namespace multiprecision { |
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| 16 | namespace detail { |
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| 17 | |
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| 18 | template <unsigned int N> |
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| 19 | struct dummy_size |
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| 20 | {}; |
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| 21 | |
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| 22 | template <typename S, typename T> |
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| 23 | struct has_generic_interconversion |
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| 24 | { |
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| 25 | using type = typename std::conditional< |
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| 26 | is_number<S>::value && is_number<T>::value, |
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| 27 | typename std::conditional< |
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| 28 | number_category<S>::value == number_kind_integer, |
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| 29 | typename std::conditional< |
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| 30 | number_category<T>::value == number_kind_integer || number_category<T>::value == number_kind_floating_point || number_category<T>::value == number_kind_rational || number_category<T>::value == number_kind_fixed_point, |
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| 31 | std::true_type, |
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| 32 | std::false_type >::type, |
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| 33 | typename std::conditional< |
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| 34 | number_category<S>::value == number_kind_rational, |
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| 35 | typename std::conditional< |
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| 36 | number_category<T>::value == number_kind_rational || number_category<T>::value == number_kind_rational, |
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| 37 | std::true_type, |
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| 38 | std::false_type >::type, |
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| 39 | typename std::conditional< |
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| 40 | number_category<T>::value == number_kind_floating_point, |
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| 41 | std::true_type, |
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| 42 | std::false_type >::type>::type>::type, |
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| 43 | std::false_type >::type; |
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| 44 | }; |
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| 45 | |
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| 46 | template <typename S, typename T> |
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| 47 | struct is_explicitly_convertible_imp |
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| 48 | { |
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| 49 | template <typename S1, typename T1> |
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| 50 | static int selector(dummy_size<static_cast<unsigned int>(sizeof(new T1(std::declval<S1>())))>*); |
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| 51 | |
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| 52 | template <typename S1, typename T1> |
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| 53 | static char selector(...); |
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| 54 | |
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| 55 | static constexpr bool value = sizeof(selector<S, T>(nullptr)) == sizeof(int); |
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| 56 | |
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| 57 | using type = std::integral_constant<bool, value>; |
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| 58 | }; |
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| 59 | |
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| 60 | template <typename From, typename To> |
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| 61 | struct is_explicitly_convertible : public is_explicitly_convertible_imp<From, To>::type |
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| 62 | { |
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| 63 | }; |
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| 64 | |
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| 65 | }}} // namespace boost::multiprecision::detail |
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| 66 | |
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| 67 | #endif |
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| 68 | |
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