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54 lines
1.2 KiB
C
54 lines
1.2 KiB
C
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// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
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// vi: set et ft=cpp ts=4 sts=4 sw=4 fenc=utf-8 :vi
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#ifndef CTL_IS_CONVERTIBLE_H_
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#define CTL_IS_CONVERTIBLE_H_
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#include "ctl/integral_constant.h"
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#include "ctl/void_t.h"
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namespace ctl {
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// Declaration of declval
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template<typename T>
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T&&
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declval() noexcept;
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namespace detail {
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template<typename From, typename To, typename = void>
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struct is_convertible_impl : false_type
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{};
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template<typename From, typename To>
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struct is_convertible_impl<From,
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To,
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void_t<decltype(static_cast<To>(declval<From>()))>>
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: true_type
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{};
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// Handle void types separately
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template<>
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struct is_convertible_impl<void, void> : true_type
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{};
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template<typename To>
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struct is_convertible_impl<void, To> : false_type
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{};
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template<typename From>
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struct is_convertible_impl<From, void> : false_type
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{};
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} // namespace detail
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template<typename From, typename To>
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struct is_convertible : detail::is_convertible_impl<From, To>
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{};
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// Helper variable template (C++17 and later)
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template<typename From, typename To>
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inline constexpr bool is_convertible_v = is_convertible<From, To>::value;
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} // namespace ctl
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#endif // CTL_IS_CONVERTIBLE_H_
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