2 * Copyright (c) 2018 Jaroslav Jindrak
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6 * modification, are permitted provided that the following conditions
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29 #ifndef LIBCPP_BITS_AUX
30 #define LIBCPP_BITS_AUX
35 * 20.10.3, helper class:
38 template<class T
, T v
>
39 struct integral_constant
41 static constexpr T value
= v
;
44 using type
= integral_constant
<T
, v
>;
46 constexpr operator value_type() const noexcept
51 constexpr value_type
operator()() const noexcept
57 using true_type
= integral_constant
<bool, true>;
58 using false_type
= integral_constant
<bool, false>;
64 * Two very handy templates, this allows us
65 * to easily follow the T::type and T::value
66 * convention by simply inheriting from specific
67 * instantiations of these templates.
69 * 1) We need a struct with int typedef'd to type:
71 * stuct has_type_int: aux::type<int> {};
72 * typename has_type_int::type x = 1; // x is of type int
74 * 2) We need a struct with static size_t member called value:
76 * struct has_value_size_t: aux::value<size_t, 1u> {};
77 * std::printf("%u\n", has_value_size_t::value); // prints "1\n"
86 // For compatibility with integral_constant.
87 template<class T
, T v
>
88 using value_is
= std::integral_constant
<T
, v
>;