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52 lines
1.4 KiB
C++
52 lines
1.4 KiB
C++
#pragma once
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#include <iterator> // random_access_iterator_tag
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#include <nlohmann/detail/meta/void_t.hpp>
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#include <nlohmann/detail/meta/cpp_future.hpp>
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namespace nlohmann
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{
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namespace detail
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{
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template<typename It, typename = void>
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struct iterator_types {};
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template<typename It>
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struct iterator_types <
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It,
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void_t<typename It::difference_type, typename It::value_type, typename It::pointer,
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typename It::reference, typename It::iterator_category >>
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{
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using difference_type = typename It::difference_type;
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using value_type = typename It::value_type;
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using pointer = typename It::pointer;
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using reference = typename It::reference;
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using iterator_category = typename It::iterator_category;
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};
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// This is required as some compilers implement std::iterator_traits in a way that
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// doesn't work with SFINAE. See https://github.com/nlohmann/json/issues/1341.
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template<typename T, typename = void>
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struct iterator_traits
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{
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};
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template<typename T>
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struct iterator_traits < T, enable_if_t < !std::is_pointer<T>::value >>
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: iterator_types<T>
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{
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};
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template<typename T>
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struct iterator_traits<T*, enable_if_t<std::is_object<T>::value>>
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{
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using iterator_category = std::random_access_iterator_tag;
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using value_type = T;
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using difference_type = ptrdiff_t;
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using pointer = T*;
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using reference = T&;
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};
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} // namespace detail
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} // namespace nlohmann
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