mirror of
https://github.com/nlohmann/json.git
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261cc4e509
Constrain from_json() overload for StringType to not accept json_ref and require it to be assignable, instead of constructible, from basic_json::string_t. Re-enable C++14 tests on Clang <4.0. Fixes #3171. Fixes #3267. Fixes #3312. Fixes #3384.
492 lines
18 KiB
C++
492 lines
18 KiB
C++
#pragma once
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#include <algorithm> // transform
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#include <array> // array
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#include <forward_list> // forward_list
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#include <iterator> // inserter, front_inserter, end
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#include <map> // map
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#include <string> // string
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#include <tuple> // tuple, make_tuple
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#include <type_traits> // is_arithmetic, is_same, is_enum, underlying_type, is_convertible
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#include <unordered_map> // unordered_map
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#include <utility> // pair, declval
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#include <valarray> // valarray
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#include <nlohmann/detail/exceptions.hpp>
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#include <nlohmann/detail/macro_scope.hpp>
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#include <nlohmann/detail/meta/cpp_future.hpp>
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#include <nlohmann/detail/meta/identity_tag.hpp>
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#include <nlohmann/detail/meta/type_traits.hpp>
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#include <nlohmann/detail/value_t.hpp>
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#if JSON_HAS_EXPERIMENTAL_FILESYSTEM
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#include <experimental/filesystem>
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namespace nlohmann::detail
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{
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namespace std_fs = std::experimental::filesystem;
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} // namespace nlohmann::detail
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#elif JSON_HAS_FILESYSTEM
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#include <filesystem>
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namespace nlohmann::detail
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{
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namespace std_fs = std::filesystem;
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} // namespace nlohmann::detail
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#endif
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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 BasicJsonType>
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void from_json(const BasicJsonType& j, typename std::nullptr_t& n)
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_null()))
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{
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JSON_THROW(type_error::create(302, "type must be null, but is " + std::string(j.type_name()), j));
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}
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n = nullptr;
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}
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// overloads for basic_json template parameters
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template < typename BasicJsonType, typename ArithmeticType,
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enable_if_t < std::is_arithmetic<ArithmeticType>::value&&
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!std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
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int > = 0 >
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void get_arithmetic_value(const BasicJsonType& j, ArithmeticType& val)
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{
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switch (static_cast<value_t>(j))
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{
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case value_t::number_unsigned:
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{
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val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
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break;
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}
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case value_t::number_integer:
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{
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val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
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break;
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}
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case value_t::number_float:
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{
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val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
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break;
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}
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case value_t::null:
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case value_t::object:
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case value_t::array:
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case value_t::string:
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case value_t::boolean:
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case value_t::binary:
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case value_t::discarded:
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default:
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JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name()), j));
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}
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}
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template<typename BasicJsonType>
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void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b)
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_boolean()))
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{
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JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(j.type_name()), j));
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}
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b = *j.template get_ptr<const typename BasicJsonType::boolean_t*>();
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}
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template<typename BasicJsonType>
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void from_json(const BasicJsonType& j, typename BasicJsonType::string_t& s)
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_string()))
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{
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JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name()), j));
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}
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s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
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}
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template <
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typename BasicJsonType, typename StringType,
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enable_if_t <
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std::is_assignable<StringType&, const typename BasicJsonType::string_t>::value
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&& !std::is_same<typename BasicJsonType::string_t, StringType>::value
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&& !is_json_ref<StringType>::value, int > = 0 >
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void from_json(const BasicJsonType& j, StringType& s)
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_string()))
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{
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JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name()), j));
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}
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s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
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}
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template<typename BasicJsonType>
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void from_json(const BasicJsonType& j, typename BasicJsonType::number_float_t& val)
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{
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get_arithmetic_value(j, val);
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}
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template<typename BasicJsonType>
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void from_json(const BasicJsonType& j, typename BasicJsonType::number_unsigned_t& val)
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{
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get_arithmetic_value(j, val);
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}
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template<typename BasicJsonType>
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void from_json(const BasicJsonType& j, typename BasicJsonType::number_integer_t& val)
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{
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get_arithmetic_value(j, val);
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}
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template<typename BasicJsonType, typename EnumType,
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enable_if_t<std::is_enum<EnumType>::value, int> = 0>
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void from_json(const BasicJsonType& j, EnumType& e)
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{
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typename std::underlying_type<EnumType>::type val;
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get_arithmetic_value(j, val);
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e = static_cast<EnumType>(val);
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}
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// forward_list doesn't have an insert method
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template<typename BasicJsonType, typename T, typename Allocator,
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enable_if_t<is_getable<BasicJsonType, T>::value, int> = 0>
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void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l)
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
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{
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JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
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}
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l.clear();
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std::transform(j.rbegin(), j.rend(),
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std::front_inserter(l), [](const BasicJsonType & i)
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{
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return i.template get<T>();
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});
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}
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// valarray doesn't have an insert method
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template<typename BasicJsonType, typename T,
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enable_if_t<is_getable<BasicJsonType, T>::value, int> = 0>
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void from_json(const BasicJsonType& j, std::valarray<T>& l)
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
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{
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JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
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}
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l.resize(j.size());
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std::transform(j.begin(), j.end(), std::begin(l),
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[](const BasicJsonType & elem)
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{
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return elem.template get<T>();
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});
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}
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template<typename BasicJsonType, typename T, std::size_t N>
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auto from_json(const BasicJsonType& j, T (&arr)[N]) // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
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-> decltype(j.template get<T>(), void())
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{
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for (std::size_t i = 0; i < N; ++i)
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{
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arr[i] = j.at(i).template get<T>();
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}
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}
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template<typename BasicJsonType>
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void from_json_array_impl(const BasicJsonType& j, typename BasicJsonType::array_t& arr, priority_tag<3> /*unused*/)
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{
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arr = *j.template get_ptr<const typename BasicJsonType::array_t*>();
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}
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template<typename BasicJsonType, typename T, std::size_t N>
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auto from_json_array_impl(const BasicJsonType& j, std::array<T, N>& arr,
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priority_tag<2> /*unused*/)
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-> decltype(j.template get<T>(), void())
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{
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for (std::size_t i = 0; i < N; ++i)
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{
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arr[i] = j.at(i).template get<T>();
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}
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}
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template<typename BasicJsonType, typename ConstructibleArrayType,
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enable_if_t<
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std::is_assignable<ConstructibleArrayType&, ConstructibleArrayType>::value,
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int> = 0>
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auto from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr, priority_tag<1> /*unused*/)
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-> decltype(
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arr.reserve(std::declval<typename ConstructibleArrayType::size_type>()),
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j.template get<typename ConstructibleArrayType::value_type>(),
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void())
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{
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using std::end;
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ConstructibleArrayType ret;
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ret.reserve(j.size());
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std::transform(j.begin(), j.end(),
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std::inserter(ret, end(ret)), [](const BasicJsonType & i)
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{
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// get<BasicJsonType>() returns *this, this won't call a from_json
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// method when value_type is BasicJsonType
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return i.template get<typename ConstructibleArrayType::value_type>();
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});
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arr = std::move(ret);
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}
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template<typename BasicJsonType, typename ConstructibleArrayType,
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enable_if_t<
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std::is_assignable<ConstructibleArrayType&, ConstructibleArrayType>::value,
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int> = 0>
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void from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr,
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priority_tag<0> /*unused*/)
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{
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using std::end;
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ConstructibleArrayType ret;
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std::transform(
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j.begin(), j.end(), std::inserter(ret, end(ret)),
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[](const BasicJsonType & i)
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{
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// get<BasicJsonType>() returns *this, this won't call a from_json
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// method when value_type is BasicJsonType
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return i.template get<typename ConstructibleArrayType::value_type>();
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});
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arr = std::move(ret);
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}
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template < typename BasicJsonType, typename ConstructibleArrayType,
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enable_if_t <
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is_constructible_array_type<BasicJsonType, ConstructibleArrayType>::value&&
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!is_constructible_object_type<BasicJsonType, ConstructibleArrayType>::value&&
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!is_constructible_string_type<BasicJsonType, ConstructibleArrayType>::value&&
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!std::is_same<ConstructibleArrayType, typename BasicJsonType::binary_t>::value&&
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!is_basic_json<ConstructibleArrayType>::value,
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int > = 0 >
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auto from_json(const BasicJsonType& j, ConstructibleArrayType& arr)
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-> decltype(from_json_array_impl(j, arr, priority_tag<3> {}),
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j.template get<typename ConstructibleArrayType::value_type>(),
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void())
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
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{
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JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
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}
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from_json_array_impl(j, arr, priority_tag<3> {});
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}
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template < typename BasicJsonType, typename T, std::size_t... Idx >
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std::array<T, sizeof...(Idx)> from_json_inplace_array_impl(BasicJsonType&& j,
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identity_tag<std::array<T, sizeof...(Idx)>> /*unused*/, index_sequence<Idx...> /*unused*/)
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{
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return { { std::forward<BasicJsonType>(j).at(Idx).template get<T>()... } };
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}
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template < typename BasicJsonType, typename T, std::size_t N >
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auto from_json(BasicJsonType&& j, identity_tag<std::array<T, N>> tag)
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-> decltype(from_json_inplace_array_impl(std::forward<BasicJsonType>(j), tag, make_index_sequence<N> {}))
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
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{
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JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
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}
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return from_json_inplace_array_impl(std::forward<BasicJsonType>(j), tag, make_index_sequence<N> {});
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}
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template<typename BasicJsonType>
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void from_json(const BasicJsonType& j, typename BasicJsonType::binary_t& bin)
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_binary()))
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{
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JSON_THROW(type_error::create(302, "type must be binary, but is " + std::string(j.type_name()), j));
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}
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bin = *j.template get_ptr<const typename BasicJsonType::binary_t*>();
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}
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template<typename BasicJsonType, typename ConstructibleObjectType,
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enable_if_t<is_constructible_object_type<BasicJsonType, ConstructibleObjectType>::value, int> = 0>
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void from_json(const BasicJsonType& j, ConstructibleObjectType& obj)
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_object()))
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{
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JSON_THROW(type_error::create(302, "type must be object, but is " + std::string(j.type_name()), j));
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}
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ConstructibleObjectType ret;
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const auto* inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
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using value_type = typename ConstructibleObjectType::value_type;
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std::transform(
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inner_object->begin(), inner_object->end(),
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std::inserter(ret, ret.begin()),
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[](typename BasicJsonType::object_t::value_type const & p)
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{
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return value_type(p.first, p.second.template get<typename ConstructibleObjectType::mapped_type>());
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});
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obj = std::move(ret);
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}
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// overload for arithmetic types, not chosen for basic_json template arguments
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// (BooleanType, etc..); note: Is it really necessary to provide explicit
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// overloads for boolean_t etc. in case of a custom BooleanType which is not
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// an arithmetic type?
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template < typename BasicJsonType, typename ArithmeticType,
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enable_if_t <
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std::is_arithmetic<ArithmeticType>::value&&
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!std::is_same<ArithmeticType, typename BasicJsonType::number_unsigned_t>::value&&
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!std::is_same<ArithmeticType, typename BasicJsonType::number_integer_t>::value&&
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!std::is_same<ArithmeticType, typename BasicJsonType::number_float_t>::value&&
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!std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
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int > = 0 >
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void from_json(const BasicJsonType& j, ArithmeticType& val)
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{
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switch (static_cast<value_t>(j))
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{
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case value_t::number_unsigned:
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{
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val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
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break;
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}
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case value_t::number_integer:
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{
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val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
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break;
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}
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case value_t::number_float:
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{
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val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
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break;
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}
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case value_t::boolean:
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{
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val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::boolean_t*>());
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break;
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}
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case value_t::null:
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case value_t::object:
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case value_t::array:
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case value_t::string:
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case value_t::binary:
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case value_t::discarded:
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default:
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JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name()), j));
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}
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}
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template<typename BasicJsonType, typename... Args, std::size_t... Idx>
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std::tuple<Args...> from_json_tuple_impl_base(BasicJsonType&& j, index_sequence<Idx...> /*unused*/)
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{
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return std::make_tuple(std::forward<BasicJsonType>(j).at(Idx).template get<Args>()...);
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}
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template < typename BasicJsonType, class A1, class A2 >
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std::pair<A1, A2> from_json_tuple_impl(BasicJsonType&& j, identity_tag<std::pair<A1, A2>> /*unused*/, priority_tag<0> /*unused*/)
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{
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return {std::forward<BasicJsonType>(j).at(0).template get<A1>(),
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std::forward<BasicJsonType>(j).at(1).template get<A2>()};
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}
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template<typename BasicJsonType, typename A1, typename A2>
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void from_json_tuple_impl(BasicJsonType&& j, std::pair<A1, A2>& p, priority_tag<1> /*unused*/)
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{
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p = from_json_tuple_impl(std::forward<BasicJsonType>(j), identity_tag<std::pair<A1, A2>> {}, priority_tag<0> {});
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}
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template<typename BasicJsonType, typename... Args>
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std::tuple<Args...> from_json_tuple_impl(BasicJsonType&& j, identity_tag<std::tuple<Args...>> /*unused*/, priority_tag<2> /*unused*/)
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{
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return from_json_tuple_impl_base<BasicJsonType, Args...>(std::forward<BasicJsonType>(j), index_sequence_for<Args...> {});
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}
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template<typename BasicJsonType, typename... Args>
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void from_json_tuple_impl(BasicJsonType&& j, std::tuple<Args...>& t, priority_tag<3> /*unused*/)
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{
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t = from_json_tuple_impl_base<BasicJsonType, Args...>(std::forward<BasicJsonType>(j), index_sequence_for<Args...> {});
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}
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template<typename BasicJsonType, typename TupleRelated>
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auto from_json(BasicJsonType&& j, TupleRelated&& t)
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-> decltype(from_json_tuple_impl(std::forward<BasicJsonType>(j), std::forward<TupleRelated>(t), priority_tag<3> {}))
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
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{
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JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
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}
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return from_json_tuple_impl(std::forward<BasicJsonType>(j), std::forward<TupleRelated>(t), priority_tag<3> {});
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}
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template < typename BasicJsonType, typename Key, typename Value, typename Compare, typename Allocator,
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typename = enable_if_t < !std::is_constructible <
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typename BasicJsonType::string_t, Key >::value >>
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void from_json(const BasicJsonType& j, std::map<Key, Value, Compare, Allocator>& m)
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{
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if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
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{
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JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
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}
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m.clear();
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for (const auto& p : j)
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{
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if (JSON_HEDLEY_UNLIKELY(!p.is_array()))
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{
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JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name()), j));
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}
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|
m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
|
|
}
|
|
}
|
|
|
|
template < typename BasicJsonType, typename Key, typename Value, typename Hash, typename KeyEqual, typename Allocator,
|
|
typename = enable_if_t < !std::is_constructible <
|
|
typename BasicJsonType::string_t, Key >::value >>
|
|
void from_json(const BasicJsonType& j, std::unordered_map<Key, Value, Hash, KeyEqual, Allocator>& m)
|
|
{
|
|
if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
|
|
{
|
|
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
|
|
}
|
|
m.clear();
|
|
for (const auto& p : j)
|
|
{
|
|
if (JSON_HEDLEY_UNLIKELY(!p.is_array()))
|
|
{
|
|
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name()), j));
|
|
}
|
|
m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
|
|
}
|
|
}
|
|
|
|
#if JSON_HAS_FILESYSTEM || JSON_HAS_EXPERIMENTAL_FILESYSTEM
|
|
template<typename BasicJsonType>
|
|
void from_json(const BasicJsonType& j, std_fs::path& p)
|
|
{
|
|
if (JSON_HEDLEY_UNLIKELY(!j.is_string()))
|
|
{
|
|
JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name()), j));
|
|
}
|
|
p = *j.template get_ptr<const typename BasicJsonType::string_t*>();
|
|
}
|
|
#endif
|
|
|
|
struct from_json_fn
|
|
{
|
|
template<typename BasicJsonType, typename T>
|
|
auto operator()(const BasicJsonType& j, T&& val) const
|
|
noexcept(noexcept(from_json(j, std::forward<T>(val))))
|
|
-> decltype(from_json(j, std::forward<T>(val)))
|
|
{
|
|
return from_json(j, std::forward<T>(val));
|
|
}
|
|
};
|
|
} // namespace detail
|
|
|
|
/// namespace to hold default `from_json` function
|
|
/// to see why this is required:
|
|
/// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
|
|
namespace // NOLINT(cert-dcl59-cpp,fuchsia-header-anon-namespaces,google-build-namespaces)
|
|
{
|
|
constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value; // NOLINT(misc-definitions-in-headers)
|
|
} // namespace
|
|
} // namespace nlohmann
|