json.hpp

    }
    b = *j.template get_ptr<const typename BasicJsonType::boolean_t*>();
}

template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::string_t& s)
{
    if (JSON_UNLIKELY(not j.is_string()))
    {
        JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name())));
    }
    s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
}

template <
    typename BasicJsonType, typename CompatibleStringType,
    enable_if_t <
        is_compatible_string_type<BasicJsonType, CompatibleStringType>::value and
        not std::is_same<typename BasicJsonType::string_t,
                         CompatibleStringType>::value,
        int > = 0 >
void from_json(const BasicJsonType& j, CompatibleStringType& s)
{
    if (JSON_UNLIKELY(not j.is_string()))
    {
        JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name())));
    }

    s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
}

template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::number_float_t& val)
{
    get_arithmetic_value(j, val);
}

template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::number_unsigned_t& val)
{
    get_arithmetic_value(j, val);
}

template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::number_integer_t& val)
{
    get_arithmetic_value(j, val);
}

template<typename BasicJsonType, typename EnumType,
         enable_if_t<std::is_enum<EnumType>::value, int> = 0>
void from_json(const BasicJsonType& j, EnumType& e)
{
    typename std::underlying_type<EnumType>::type val;
    get_arithmetic_value(j, val);
    e = static_cast<EnumType>(val);
}

template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::array_t& arr)
{
    if (JSON_UNLIKELY(not j.is_array()))
    {
        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
    }
    arr = *j.template get_ptr<const typename BasicJsonType::array_t*>();
}

// forward_list doesn't have an insert method
template<typename BasicJsonType, typename T, typename Allocator,
         enable_if_t<std::is_convertible<BasicJsonType, T>::value, int> = 0>
void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l)
{
    if (JSON_UNLIKELY(not j.is_array()))
    {
        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
    }
    std::transform(j.rbegin(), j.rend(),
                   std::front_inserter(l), [](const BasicJsonType & i)
    {
        return i.template get<T>();
    });
}

// valarray doesn't have an insert method
template<typename BasicJsonType, typename T,
         enable_if_t<std::is_convertible<BasicJsonType, T>::value, int> = 0>
void from_json(const BasicJsonType& j, std::valarray<T>& l)
{
    if (JSON_UNLIKELY(not j.is_array()))
    {
        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
    }
    l.resize(j.size());
    std::copy(j.m_value.array->begin(), j.m_value.array->end(), std::begin(l));
}

template<typename BasicJsonType, typename CompatibleArrayType>
void from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<0> /*unused*/)
{
    using std::end;

    std::transform(j.begin(), j.end(),
                   std::inserter(arr, end(arr)), [](const BasicJsonType & i)
    {
        // get<BasicJsonType>() returns *this, this won't call a from_json
        // method when value_type is BasicJsonType
        return i.template get<typename CompatibleArrayType::value_type>();
    });
}

template<typename BasicJsonType, typename CompatibleArrayType>
auto from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<1> /*unused*/)
-> decltype(
    arr.reserve(std::declval<typename CompatibleArrayType::size_type>()),
    void())
{
    using std::end;

    arr.reserve(j.size());
    std::transform(j.begin(), j.end(),
                   std::inserter(arr, end(arr)), [](const BasicJsonType & i)
    {
        // get<BasicJsonType>() returns *this, this won't call a from_json
        // method when value_type is BasicJsonType
        return i.template get<typename CompatibleArrayType::value_type>();
    });
}

template<typename BasicJsonType, typename T, std::size_t N>
void from_json_array_impl(const BasicJsonType& j, std::array<T, N>& arr, priority_tag<2> /*unused*/)
{
    for (std::size_t i = 0; i < N; ++i)
    {
        arr[i] = j.at(i).template get<T>();
    }
}

template <
    typename BasicJsonType, typename CompatibleArrayType,
    enable_if_t <
        is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value and
        not std::is_same<typename BasicJsonType::array_t,
                         CompatibleArrayType>::value and
        std::is_constructible <
            BasicJsonType, typename CompatibleArrayType::value_type >::value,
        int > = 0 >
void from_json(const BasicJsonType& j, CompatibleArrayType& arr)
{
    if (JSON_UNLIKELY(not j.is_array()))
    {
        JSON_THROW(type_error::create(302, "type must be array, but is " +
                                      std::string(j.type_name())));
    }

    from_json_array_impl(j, arr, priority_tag<2> {});
}

template<typename BasicJsonType, typename CompatibleObjectType,
         enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value, int> = 0>
void from_json(const BasicJsonType& j, CompatibleObjectType& obj)
{
    if (JSON_UNLIKELY(not j.is_object()))
    {
        JSON_THROW(type_error::create(302, "type must be object, but is " + std::string(j.type_name())));
    }

    auto inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
    using value_type = typename CompatibleObjectType::value_type;
    std::transform(
        inner_object->begin(), inner_object->end(),
        std::inserter(obj, obj.begin()),
        [](typename BasicJsonType::object_t::value_type const & p)
    {
        return value_type(p.first, p.second.template get<typename CompatibleObjectType::mapped_type>());
    });
}

// overload for arithmetic types, not chosen for basic_json template arguments
// (BooleanType, etc..); note: Is it really necessary to provide explicit
// overloads for boolean_t etc. in case of a custom BooleanType which is not
// an arithmetic type?
template<typename BasicJsonType, typename ArithmeticType,
         enable_if_t <
             std::is_arithmetic<ArithmeticType>::value and
             not std::is_same<ArithmeticType, typename BasicJsonType::number_unsigned_t>::value and
             not std::is_same<ArithmeticType, typename BasicJsonType::number_integer_t>::value and
             not std::is_same<ArithmeticType, typename BasicJsonType::number_float_t>::value and
             not std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
             int> = 0>
void from_json(const BasicJsonType& j, ArithmeticType& val)
{
    switch (static_cast<value_t>(j))
    {
        case value_t::number_unsigned:
        {
            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
            break;
        }
        case value_t::number_integer:
        {
            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
            break;
        }
        case value_t::number_float:
        {
            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
            break;
        }
        case value_t::boolean:
        {
            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::boolean_t*>());
            break;
        }

        default:
            JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name())));
    }
}

template<typename BasicJsonType, typename A1, typename A2>
void from_json(const BasicJsonType& j, std::pair<A1, A2>& p)
{
    p = {j.at(0).template get<A1>(), j.at(1).template get<A2>()};
}

template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
void from_json_tuple_impl(const BasicJsonType& j, Tuple& t, index_sequence<Idx...>)
{
    t = std::make_tuple(j.at(Idx).template get<typename std::tuple_element<Idx, Tuple>::type>()...);
}

template<typename BasicJsonType, typename... Args>
void from_json(const BasicJsonType& j, std::tuple<Args...>& t)
{
    from_json_tuple_impl(j, t, index_sequence_for<Args...> {});
}

template <typename BasicJsonType, typename Key, typename Value, typename Compare, typename Allocator,
          typename = enable_if_t<not std::is_constructible<
                                     typename BasicJsonType::string_t, Key>::value>>
void from_json(const BasicJsonType& j, std::map<Key, Value, Compare, Allocator>& m)
{
    if (JSON_UNLIKELY(not j.is_array()))
    {
        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
    }
    for (const auto& p : j)
    {
        if (JSON_UNLIKELY(not p.is_array()))
        {
            JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name())));
        }
        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<not 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_UNLIKELY(not j.is_array()))
    {
        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
    }
    for (const auto& p : j)
    {
        if (JSON_UNLIKELY(not p.is_array()))
        {
            JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name())));
        }
        m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
    }
}

struct from_json_fn
{
  private:
    template<typename BasicJsonType, typename T>
    auto call(const BasicJsonType& j, T& val, priority_tag<1> /*unused*/) const
    noexcept(noexcept(from_json(j, val)))
    -> decltype(from_json(j, val), void())
    {
        return from_json(j, val);
    }

    template<typename BasicJsonType, typename T>
    void call(const BasicJsonType& /*unused*/, T& /*unused*/, priority_tag<0> /*unused*/) const noexcept
    {
        static_assert(sizeof(BasicJsonType) == 0,
                      "could not find from_json() method in T's namespace");
#ifdef _MSC_VER
        // MSVC does not show a stacktrace for the above assert
        using decayed = uncvref_t<T>;
        static_assert(sizeof(typename decayed::force_msvc_stacktrace) == 0,
                      "forcing MSVC stacktrace to show which T we're talking about.");
#endif
    }

  public:
    template<typename BasicJsonType, typename T>
    void operator()(const BasicJsonType& j, T& val) const
    noexcept(noexcept(std::declval<from_json_fn>().call(j, val, priority_tag<1> {})))
    {
        return call(j, val, priority_tag<1> {});
    }
};
}

/// 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
{
constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value;
}
}

// #include <nlohmann/detail/conversions/to_json.hpp>


#include <ciso646> // or, and, not
#include <iterator> // begin, end
#include <tuple> // tuple, get
#include <type_traits> // is_same, is_constructible, is_floating_point, is_enum, underlying_type
#include <utility> // move, forward, declval, pair
#include <valarray> // valarray
#include <vector> // vector

// #include <nlohmann/detail/meta.hpp>

// #include <nlohmann/detail/value_t.hpp>

// #include <nlohmann/detail/iterators/iteration_proxy.hpp>


#include <cstddef> // size_t
#include <string> // string, to_string
#include <iterator> // input_iterator_tag

// #include <nlohmann/detail/value_t.hpp>


namespace nlohmann
{
namespace detail
{
/// proxy class for the items() function
template<typename IteratorType> class iteration_proxy
{
  private:
    /// helper class for iteration
    class iteration_proxy_internal
    {
      public:
        using difference_type = std::ptrdiff_t;
        using value_type = iteration_proxy_internal;
        using pointer = iteration_proxy_internal*;
        using reference = iteration_proxy_internal&;
        using iterator_category = std::input_iterator_tag;

      private:
        /// the iterator
        IteratorType anchor;
        /// an index for arrays (used to create key names)
        std::size_t array_index = 0;
        /// last stringified array index
        mutable std::size_t array_index_last = 0;
        /// a string representation of the array index
        mutable std::string array_index_str = "0";
        /// an empty string (to return a reference for primitive values)
        const std::string empty_str = "";

      public:
        explicit iteration_proxy_internal(IteratorType it) noexcept : anchor(it) {}

        iteration_proxy_internal(const iteration_proxy_internal&) = default;
        iteration_proxy_internal& operator=(const iteration_proxy_internal&) = default;

        /// dereference operator (needed for range-based for)
        iteration_proxy_internal& operator*()
        {
            return *this;
        }

        /// increment operator (needed for range-based for)
        iteration_proxy_internal& operator++()
        {
            ++anchor;
            ++array_index;

            return *this;
        }

        /// equality operator (needed for InputIterator)
        bool operator==(const iteration_proxy_internal& o) const noexcept
        {
            return anchor == o.anchor;
        }

        /// inequality operator (needed for range-based for)
        bool operator!=(const iteration_proxy_internal& o) const noexcept
        {
            return anchor != o.anchor;
        }

        /// return key of the iterator
        const std::string& key() const
        {
            assert(anchor.m_object != nullptr);

            switch (anchor.m_object->type())
            {
                // use integer array index as key
                case value_t::array:
                {
                    if (array_index != array_index_last)
                    {
                        array_index_str = std::to_string(array_index);
                        array_index_last = array_index;
                    }
                    return array_index_str;
                }

                // use key from the object
                case value_t::object:
                    return anchor.key();

                // use an empty key for all primitive types
                default:
                    return empty_str;
            }
        }

        /// return value of the iterator
        typename IteratorType::reference value() const
        {
            return anchor.value();
        }
    };

    /// the container to iterate
    typename IteratorType::reference container;

  public:
    /// construct iteration proxy from a container
    explicit iteration_proxy(typename IteratorType::reference cont) noexcept
        : container(cont) {}

    /// return iterator begin (needed for range-based for)
    iteration_proxy_internal begin() noexcept
    {
        return iteration_proxy_internal(container.begin());
    }

    /// return iterator end (needed for range-based for)
    iteration_proxy_internal end() noexcept
    {
        return iteration_proxy_internal(container.end());
    }
};
}
}


namespace nlohmann
{
namespace detail
{
//////////////////
// constructors //
//////////////////

template<value_t> struct external_constructor;

template<>
struct external_constructor<value_t::boolean>
{
    template<typename BasicJsonType>
    static void construct(BasicJsonType& j, typename BasicJsonType::boolean_t b) noexcept
    {
        j.m_type = value_t::boolean;
        j.m_value = b;
        j.assert_invariant();
    }
};

template<>
struct external_constructor<value_t::string>
{
    template<typename BasicJsonType>
    static void construct(BasicJsonType& j, const typename BasicJsonType::string_t& s)
    {
        j.m_type = value_t::string;
        j.m_value = s;
        j.assert_invariant();
    }

    template<typename BasicJsonType>
    static void construct(BasicJsonType& j, typename BasicJsonType::string_t&& s)
    {
        j.m_type = value_t::string;
        j.m_value = std::move(s);
        j.assert_invariant();
    }

    template<typename BasicJsonType, typename CompatibleStringType,
             enable_if_t<not std::is_same<CompatibleStringType, typename BasicJsonType::string_t>::value,
                         int> = 0>
    static void construct(BasicJsonType& j, const CompatibleStringType& str)
    {
        j.m_type = value_t::string;
        j.m_value.string = j.template create<typename BasicJsonType::string_t>(str);
        j.assert_invariant();
    }
};

template<>
struct external_constructor<value_t::number_float>
{
    template<typename BasicJsonType>
    static void construct(BasicJsonType& j, typename BasicJsonType::number_float_t val) noexcept
    {
        j.m_type = value_t::number_float;
        j.m_value = val;
        j.assert_invariant();
    }
};

template<>
struct external_constructor<value_t::number_unsigned>
{
    template<typename BasicJsonType>
    static void construct(BasicJsonType& j, typename BasicJsonType::number_unsigned_t val) noexcept
    {
        j.m_type = value_t::number_unsigned;
        j.m_value = val;
        j.assert_invariant();
    }
};

template<>
struct external_constructor<value_t::number_integer>
{
    template<typename BasicJsonType>
    static void construct(BasicJsonType& j, typename BasicJsonType::number_integer_t val) noexcept
    {
        j.m_type = value_t::number_integer;
        j.m_value = val;
        j.assert_invariant();
    }
};

template<>
struct external_constructor<value_t::array>
{
    template<typename BasicJsonType>
    static void construct(BasicJsonType& j, const typename BasicJsonType::array_t& arr)
    {
        j.m_type = value_t::array;
        j.m_value = arr;
        j.assert_invariant();
    }

    template<typename BasicJsonType>
    static void construct(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
    {
        j.m_type = value_t::array;
        j.m_value = std::move(arr);
        j.assert_invariant();
    }

    template<typename BasicJsonType, typename CompatibleArrayType,
             enable_if_t<not std::is_same<CompatibleArrayType, typename BasicJsonType::array_t>::value,
                         int> = 0>
    static void construct(BasicJsonType& j, const CompatibleArrayType& arr)
    {
        using std::begin;
        using std::end;
        j.m_type = value_t::array;
        j.m_value.array = j.template create<typename BasicJsonType::array_t>(begin(arr), end(arr));
        j.assert_invariant();
    }

    template<typename BasicJsonType>
    static void construct(BasicJsonType& j, const std::vector<bool>& arr)
    {
        j.m_type = value_t::array;
        j.m_value = value_t::array;
        j.m_value.array->reserve(arr.size());
        for (const bool x : arr)
        {
            j.m_value.array->push_back(x);
        }
        j.assert_invariant();
    }

    template<typename BasicJsonType, typename T,
             enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
    static void construct(BasicJsonType& j, const std::valarray<T>& arr)
    {
        j.m_type = value_t::array;
        j.m_value = value_t::array;
        j.m_value.array->resize(arr.size());
        std::copy(std::begin(arr), std::end(arr), j.m_value.array->begin());
        j.assert_invariant();
    }
};

template<>
struct external_constructor<value_t::object>
{
    template<typename BasicJsonType>
    static void construct(BasicJsonType& j, const typename BasicJsonType::object_t& obj)
    {
        j.m_type = value_t::object;
        j.m_value = obj;
        j.assert_invariant();
    }

    template<typename BasicJsonType>
    static void construct(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
    {
        j.m_type = value_t::object;
        j.m_value = std::move(obj);
        j.assert_invariant();
    }

    template<typename BasicJsonType, typename CompatibleObjectType,
             enable_if_t<not std::is_same<CompatibleObjectType, typename BasicJsonType::object_t>::value, int> = 0>
    static void construct(BasicJsonType& j, const CompatibleObjectType& obj)
    {
        using std::begin;
        using std::end;

        j.m_type = value_t::object;
        j.m_value.object = j.template create<typename BasicJsonType::object_t>(begin(obj), end(obj));
        j.assert_invariant();
    }
};

/////////////
// to_json //
/////////////

template<typename BasicJsonType, typename T,
         enable_if_t<std::is_same<T, typename BasicJsonType::boolean_t>::value, int> = 0>
void to_json(BasicJsonType& j, T b) noexcept
{
    external_constructor<value_t::boolean>::construct(j, b);
}

template<typename BasicJsonType, typename CompatibleString,
         enable_if_t<std::is_constructible<typename BasicJsonType::string_t, CompatibleString>::value, int> = 0>
void to_json(BasicJsonType& j, const CompatibleString& s)
{
    external_constructor<value_t::string>::construct(j, s);
}

template<typename BasicJsonType>
void to_json(BasicJsonType& j, typename BasicJsonType::string_t&& s)
{
    external_constructor<value_t::string>::construct(j, std::move(s));
}

template<typename BasicJsonType, typename FloatType,
         enable_if_t<std::is_floating_point<FloatType>::value, int> = 0>
void to_json(BasicJsonType& j, FloatType val) noexcept
{
    external_constructor<value_t::number_float>::construct(j, static_cast<typename BasicJsonType::number_float_t>(val));
}

template<typename BasicJsonType, typename CompatibleNumberUnsignedType,
         enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_unsigned_t, CompatibleNumberUnsignedType>::value, int> = 0>
void to_json(BasicJsonType& j, CompatibleNumberUnsignedType val) noexcept
{
    external_constructor<value_t::number_unsigned>::construct(j, static_cast<typename BasicJsonType::number_unsigned_t>(val));
}

template<typename BasicJsonType, typename CompatibleNumberIntegerType,
         enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_integer_t, CompatibleNumberIntegerType>::value, int> = 0>
void to_json(BasicJsonType& j, CompatibleNumberIntegerType val) noexcept
{
    external_constructor<value_t::number_integer>::construct(j, static_cast<typename BasicJsonType::number_integer_t>(val));
}

template<typename BasicJsonType, typename EnumType,
         enable_if_t<std::is_enum<EnumType>::value, int> = 0>
void to_json(BasicJsonType& j, EnumType e) noexcept
{
    using underlying_type = typename std::underlying_type<EnumType>::type;
    external_constructor<value_t::number_integer>::construct(j, static_cast<underlying_type>(e));
}

template<typename BasicJsonType>
void to_json(BasicJsonType& j, const std::vector<bool>& e)
{
    external_constructor<value_t::array>::construct(j, e);
}

template<typename BasicJsonType, typename CompatibleArrayType,
         enable_if_t<is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value or
                     std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value,
                     int> = 0>
void to_json(BasicJsonType& j, const CompatibleArrayType& arr)
{
    external_constructor<value_t::array>::construct(j, arr);
}

template<typename BasicJsonType, typename T,
         enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
void to_json(BasicJsonType& j, const std::valarray<T>& arr)
{
    external_constructor<value_t::array>::construct(j, std::move(arr));
}

template<typename BasicJsonType>
void to_json(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
{
    external_constructor<value_t::array>::construct(j, std::move(arr));
}

template<typename BasicJsonType, typename CompatibleObjectType,
         enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value, int> = 0>
void to_json(BasicJsonType& j, const CompatibleObjectType& obj)
{
    external_constructor<value_t::object>::construct(j, obj);
}

template<typename BasicJsonType>
void to_json(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
{
    external_constructor<value_t::object>::construct(j, std::move(obj));
}

template<typename BasicJsonType, typename T, std::size_t N,
         enable_if_t<not std::is_constructible<typename BasicJsonType::string_t, T (&)[N]>::value, int> = 0>
void to_json(BasicJsonType& j, T (&arr)[N])
{
    external_constructor<value_t::array>::construct(j, arr);
}

template<typename BasicJsonType, typename... Args>
void to_json(BasicJsonType& j, const std::pair<Args...>& p)
{
    j = {p.first, p.second};
}

// for https://github.com/nlohmann/json/pull/1134
template<typename BasicJsonType, typename T,
         enable_if_t<std::is_same<T, typename iteration_proxy<typename BasicJsonType::iterator>::iteration_proxy_internal>::value, int> = 0>
void to_json(BasicJsonType& j, T b) noexcept
{
    j = {{b.key(), b.value()}};
}

template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<Idx...>)
{
    j = {std::get<Idx>(t)...};
}

template<typename BasicJsonType, typename... Args>
void to_json(BasicJsonType& j, const std::tuple<Args...>& t)
{
    to_json_tuple_impl(j, t, index_sequence_for<Args...> {});
}

struct to_json_fn
{
  private:
    template<typename BasicJsonType, typename T>
    auto call(BasicJsonType& j, T&& val, priority_tag<1> /*unused*/) const noexcept(noexcept(to_json(j, std::forward<T>(val))))
    -> decltype(to_json(j, std::forward<T>(val)), void())
    {
        return to_json(j, std::forward<T>(val));
    }

    template<typename BasicJsonType, typename T>
    void call(BasicJsonType& /*unused*/, T&& /*unused*/, priority_tag<0> /*unused*/) const noexcept
    {
        static_assert(sizeof(BasicJsonType) == 0,
                      "could not find to_json() method in T's namespace");

#ifdef _MSC_VER
        // MSVC does not show a stacktrace for the above assert
        using decayed = uncvref_t<T>;
        static_assert(sizeof(typename decayed::force_msvc_stacktrace) == 0,
                      "forcing MSVC stacktrace to show which T we're talking about.");
#endif
    }

  public:
    template<typename BasicJsonType, typename T>
    void operator()(BasicJsonType& j, T&& val) const
    noexcept(noexcept(std::declval<to_json_fn>().call(j, std::forward<T>(val), priority_tag<1> {})))
    {
        return call(j, std::forward<T>(val), priority_tag<1> {});
    }
};
}

/// namespace to hold default `to_json` function
namespace
{
constexpr const auto& to_json = detail::static_const<detail::to_json_fn>::value;
}
}

// #include <nlohmann/detail/input/input_adapters.hpp>


#include <cassert> // assert
#include <cstddef> // size_t
#include <cstring> // strlen
#include <istream> // istream
#include <iterator> // begin, end, iterator_traits, random_access_iterator_tag, distance, next
#include <memory> // shared_ptr, make_shared, addressof
#include <numeric> // accumulate
#include <string> // string, char_traits
#include <type_traits> // enable_if, is_base_of, is_pointer, is_integral, remove_pointer
#include <utility> // pair, declval

// #include <nlohmann/detail/macro_scope.hpp>


namespace nlohmann
{
namespace detail
{
/// the supported input formats
enum class input_format_t { json, cbor, msgpack, ubjson };

////////////////////
// input adapters //
////////////////////

/*!
@brief abstract input adapter interface

Produces a stream of std::char_traits<char>::int_type characters from a
std::istream, a buffer, or some other input type. Accepts the return of
exactly one non-EOF character for future input. The int_type characters
returned consist of all valid char values as positive values (typically
unsigned char), plus an EOF value outside that range, specified by the value
of the function std::char_traits<char>::eof(). This value is typically -1, but
could be any arbitrary value which is not a valid char value.
*/
struct input_adapter_protocol
{
    /// get a character [0,255] or std::char_traits<char>::eof().
    virtual std::char_traits<char>::int_type get_character() = 0;
    virtual ~input_adapter_protocol() = default;
};

/// a type to simplify interfaces
using input_adapter_t = std::shared_ptr<input_adapter_protocol>;

/*!
Input adapter for a (caching) istream. Ignores a UFT Byte Order Mark at
beginning of input. Does not support changing the underlying std::streambuf
in mid-input. Maintains underlying std::istream and std::streambuf to support
subsequent use of standard std::istream operations to process any input
characters following those used in parsing the JSON input.  Clears the
std::istream flags; any input errors (e.g., EOF) will be detected by the first
subsequent call for input from the std::istream.
*/
class input_stream_adapter : public input_adapter_protocol
{
  public:
    ~input_stream_adapter() override
    {
        // clear stream flags; we use underlying streambuf I/O, do not
        // maintain ifstream flags
        is.clear();
    }

    explicit input_stream_adapter(std::istream& i)
        : is(i), sb(*i.rdbuf())
    {}

    // delete because of pointer members
    input_stream_adapter(const input_stream_adapter&) = delete;
    input_stream_adapter& operator=(input_stream_adapter&) = delete;

    // std::istream/std::streambuf use std::char_traits<char>::to_int_type, to
    // ensure that std::char_traits<char>::eof() and the character 0xFF do not
    // end up as the same value, eg. 0xFFFFFFFF.
    std::char_traits<char>::int_type get_character() override
    {
        return sb.sbumpc();
    }

  private:
    /// the associated input stream
    std::istream& is;
    std::streambuf& sb;
};

/// input adapter for buffer input
class input_buffer_adapter : public input_adapter_protocol
{
  public:
    input_buffer_adapter(const char* b, const std::size_t l)
        : cursor(b), limit(b + l)
    {}

    // delete because of pointer members
    input_buffer_adapter(const input_buffer_adapter&) = delete;
    input_buffer_adapter& operator=(input_buffer_adapter&) = delete;

    std::char_traits<char>::int_type get_character() noexcept override
    {
        if (JSON_LIKELY(cursor < limit))
        {
            return std::char_traits<char>::to_int_type(*(cursor++));
        }

        return std::char_traits<char>::eof();
    }

  private:
    /// pointer to the current character
    const char* cursor;
    /// pointer past the last character
    const char* const limit;
};

template<typename WideStringType>
class wide_string_input_adapter : public input_adapter_protocol
{
  public:
    explicit wide_string_input_adapter(const WideStringType& w) : str(w) {}

    std::char_traits<char>::int_type get_character() noexcept override
    {
        // check if buffer needs to be filled
        if (utf8_bytes_index == utf8_bytes_filled)
        {
            if (sizeof(typename WideStringType::value_type) == 2)
            {
                fill_buffer_utf16();
            }
            else
            {
                fill_buffer_utf32();
            }

            assert(utf8_bytes_filled > 0);
            assert(utf8_bytes_index == 0);
        }

        // use buffer
        assert(utf8_bytes_filled > 0);
        assert(utf8_bytes_index < utf8_bytes_filled);
        return utf8_bytes[utf8_bytes_index++];
    }

  private:
    void fill_buffer_utf16()
    {
        utf8_bytes_index = 0;

        if (current_wchar == str.size())
        {
            utf8_bytes[0] = std::char_traits<char>::eof();
            utf8_bytes_filled = 1;
        }
        else
        {
            // get the current character
            const int wc = static_cast<int>(str[current_wchar++]);

            // UTF-16 to UTF-8 encoding
            if (wc < 0x80)
            {
                utf8_bytes[0] = wc;
                utf8_bytes_filled = 1;
            }
            else if (wc <= 0x7FF)
            {
                utf8_bytes[0] = 0xC0 | ((wc >> 6));
                utf8_bytes[1] = 0x80 | (wc & 0x3F);
                utf8_bytes_filled = 2;
            }
            else if (0xD800 > wc or wc >= 0xE000)
            {
                utf8_bytes[0] = 0xE0 | ((wc >> 12));
                utf8_bytes[1] = 0x80 | ((wc >> 6) & 0x3F);
                utf8_bytes[2] = 0x80 | (wc & 0x3F);
                utf8_bytes_filled = 3;
            }
            else
            {
                if (current_wchar < str.size())
                {
                    const int wc2 = static_cast<int>(str[current_wchar++]);
                    const int charcode = 0x10000 + (((wc & 0x3FF) << 10) | (wc2 & 0x3FF));
                    utf8_bytes[0] = 0xf0 | (charcode >> 18);