1 #pragma once 2 3 #include <cstddef> // size_t 4 #include <type_traits> // conditional, enable_if, false_type, integral_constant, is_constructible, is_integral, is_same, remove_cv, remove_reference, true_type 5 6 namespace nlohmann 7 { 8 namespace detail 9 { 10 // alias templates to reduce boilerplate 11 template<bool B, typename T = void> 12 using enable_if_t = typename std::enable_if<B, T>::type; 13 14 template<typename T> 15 using uncvref_t = typename std::remove_cv<typename std::remove_reference<T>::type>::type; 16 17 // implementation of C++14 index_sequence and affiliates 18 // source: https://stackoverflow.com/a/32223343 19 template<std::size_t... Ints> 20 struct index_sequence 21 { 22 using type = index_sequence; 23 using value_type = std::size_t; sizenlohmann::detail::index_sequence24 static constexpr std::size_t size() noexcept 25 { 26 return sizeof...(Ints); 27 } 28 }; 29 30 template<class Sequence1, class Sequence2> 31 struct merge_and_renumber; 32 33 template<std::size_t... I1, std::size_t... I2> 34 struct merge_and_renumber<index_sequence<I1...>, index_sequence<I2...>> 35 : index_sequence < I1..., (sizeof...(I1) + I2)... > {}; 36 37 template<std::size_t N> 38 struct make_index_sequence 39 : merge_and_renumber < typename make_index_sequence < N / 2 >::type, 40 typename make_index_sequence < N - N / 2 >::type > {}; 41 42 template<> struct make_index_sequence<0> : index_sequence<> {}; 43 template<> struct make_index_sequence<1> : index_sequence<0> {}; 44 45 template<typename... Ts> 46 using index_sequence_for = make_index_sequence<sizeof...(Ts)>; 47 48 // dispatch utility (taken from ranges-v3) 49 template<unsigned N> struct priority_tag : priority_tag < N - 1 > {}; 50 template<> struct priority_tag<0> {}; 51 52 // taken from ranges-v3 53 template<typename T> 54 struct static_const 55 { 56 static constexpr T value{}; 57 }; 58 59 template<typename T> 60 constexpr T static_const<T>::value; 61 } // namespace detail 62 } // namespace nlohmann 63