json.hpp

/*
    __ _____ _____ _____
 __|  |   __|     |   | |  JSON for Modern C++
|  |  |__   |  |  | | | |  version 3.1.1
|_____|_____|_____|_|___|  https://github.com/nlohmann/json

Licensed under the MIT License <http://opensource.org/licenses/MIT>.
Copyright (c) 2013-2018 Niels Lohmann <http://nlohmann.me>.

Permission is hereby  granted, free of charge, to any  person obtaining a copy
of this software and associated  documentation files (the "Software"), to deal
in the Software  without restriction, including without  limitation the rights
to  use, copy,  modify, merge,  publish, distribute,  sublicense, and/or  sell
copies  of  the Software,  and  to  permit persons  to  whom  the Software  is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
FITNESS FOR  A PARTICULAR PURPOSE AND  NONINFRINGEMENT. IN NO EVENT  SHALL THE
AUTHORS  OR COPYRIGHT  HOLDERS  BE  LIABLE FOR  ANY  CLAIM,  DAMAGES OR  OTHER
LIABILITY, WHETHER IN AN ACTION OF  CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

#ifndef NLOHMANN_JSON_HPP
#define NLOHMANN_JSON_HPP

#define NLOHMANN_JSON_VERSION_MAJOR 3
#define NLOHMANN_JSON_VERSION_MINOR 1
#define NLOHMANN_JSON_VERSION_PATCH 1

#include <algorithm> // all_of, find, for_each
#include <cassert> // assert
#include <ciso646> // and, not, or
#include <cstddef> // nullptr_t, ptrdiff_t, size_t
#include <functional> // hash, less
#include <initializer_list> // initializer_list
#include <iosfwd> // istream, ostream
#include <iterator> // iterator_traits, random_access_iterator_tag
#include <numeric> // accumulate
#include <string> // string, stoi, to_string
#include <utility> // declval, forward, move, pair, swap

// #include <nlohmann/json_fwd.hpp>
#ifndef NLOHMANN_JSON_FWD_HPP
#define NLOHMANN_JSON_FWD_HPP

#include <cstdint> // int64_t, uint64_t
#include <map> // map
#include <memory> // allocator
#include <string> // string
#include <vector> // vector

namespace nlohmann
{
template<typename = void, typename = void>
struct adl_serializer;

template<template<typename U, typename V, typename... Args> class ObjectType =
             std::map,
         template<typename U, typename... Args> class ArrayType = std::vector,
         class StringType = std::string, class BooleanType = bool,
         class NumberIntegerType = std::int64_t,
         class NumberUnsignedType = std::uint64_t,
         class NumberFloatType = double,
         template<typename U> class AllocatorType = std::allocator,
         template<typename T, typename SFINAE = void> class JSONSerializer =
             adl_serializer>
class basic_json;

template<typename BasicJsonType>
class json_pointer;

using json = basic_json<>;
} // namespace nlohmann

#endif

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


// This file contains all internal macro definitions
// You MUST include macro_unscope.hpp at the end of json.hpp to undef all of them

// exclude unsupported compilers
#if defined(__clang__)
    #if (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__) < 30400
        #error "unsupported Clang version - see https:// github.com/nlohmann/json#supported-compilers"
    #endif
#elif defined(__GNUC__) && !(defined(__ICC) || defined(__INTEL_COMPILER))
    #if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40900
        #error "unsupported GCC version - see https:// github.com/nlohmann/json#supported-compilers"
    #endif
#endif

// disable float-equal warnings on GCC/clang
#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
    #pragma GCC diagnostic push
    #pragma GCC diagnostic ignored "-Wfloat-equal"
#endif

// disable documentation warnings on clang
#if defined(__clang__)
    #pragma GCC diagnostic push
    #pragma GCC diagnostic ignored "-Wdocumentation"
#endif

// allow for portable deprecation warnings
#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
    #define JSON_DEPRECATED __attribute__ ((deprecated))
#elif defined(_MSC_VER)
    #define JSON_DEPRECATED __declspec(deprecated)
#else
    #define JSON_DEPRECATED
#endif

// allow to disable exceptions
#if (defined(__cpp_exceptions) || defined(__EXCEPTIONS) || defined(_CPPUNWIND)) && !defined(JSON_NOEXCEPTION)
    #define JSON_THROW(exception) throw exception
    #define JSON_TRY try
    #define JSON_CATCH(exception) catch (exception)
#else
    #define JSON_THROW(exception) std::abort()
    #define JSON_TRY if (true)
    #define JSON_CATCH(exception) if (false)
#endif

// override exception macros
#if defined(JSON_THROW_USER)
    #undef JSON_THROW
    #define JSON_THROW JSON_THROW_USER
#endif
#if defined(JSON_TRY_USER)
    #undef JSON_TRY
    #define JSON_TRY JSON_TRY_USER
#endif
#if defined(JSON_CATCH_USER)
    #undef JSON_CATCH
    #define JSON_CATCH JSON_CATCH_USER
#endif

// manual branch prediction
#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
    #define JSON_LIKELY(x)      __builtin_expect(!!(x), 1)
    #define JSON_UNLIKELY(x)    __builtin_expect(!!(x), 0)
#else
    #define JSON_LIKELY(x)      x
    #define JSON_UNLIKELY(x)    x
#endif

// C++ language standard detection
#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
    #define JSON_HAS_CPP_17
    #define JSON_HAS_CPP_14
#elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)
    #define JSON_HAS_CPP_14
#endif

// Ugly macros to avoid uglier copy-paste when specializing basic_json. They
// may be removed in the future once the class is split.

#define NLOHMANN_BASIC_JSON_TPL_DECLARATION                                \
    template<template<typename, typename, typename...> class ObjectType,   \
             template<typename, typename...> class ArrayType,              \
             class StringType, class BooleanType, class NumberIntegerType, \
             class NumberUnsignedType, class NumberFloatType,              \
             template<typename> class AllocatorType,                       \
             template<typename, typename = void> class JSONSerializer>

#define NLOHMANN_BASIC_JSON_TPL                                            \
    basic_json<ObjectType, ArrayType, StringType, BooleanType,             \
               NumberIntegerType, NumberUnsignedType, NumberFloatType,                \
               AllocatorType, JSONSerializer>

#define NLOHMANN_JSON_HAS_HELPER(type)                                        \
    template<typename T> struct has_ ## type {                                  \
    private:                                                                  \
        template<typename U, typename = typename U::type>                     \
        static int detect(U &&);                                              \
        static void detect(...);                                              \
    public:                                                                   \
        static constexpr bool value =                                         \
            std::is_integral<decltype(detect(std::declval<T>()))>::value; \
    }

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


#include <ciso646> // not
#include <cstddef> // size_t
#include <limits> // numeric_limits
#include <type_traits> // conditional, enable_if, false_type, integral_constant, is_constructible, is_integral, is_same, remove_cv, remove_reference, true_type
#include <utility> // declval

// #include <nlohmann/json_fwd.hpp>

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


namespace nlohmann
{
namespace detail
{
// helpers //

template<typename> struct is_basic_json : std::false_type {};

NLOHMANN_BASIC_JSON_TPL_DECLARATION
struct is_basic_json<NLOHMANN_BASIC_JSON_TPL> : std::true_type {};

// alias templates to reduce boilerplate
template<bool B, typename T = void>
using enable_if_t = typename std::enable_if<B, T>::type;

template<typename T>
using uncvref_t = typename std::remove_cv<typename std::remove_reference<T>::type>::type;

// implementation of C++14 index_sequence and affiliates
// source: https://stackoverflow.com/a/32223343
template<std::size_t... Ints>
struct index_sequence
{
    using type = index_sequence;
    using value_type = std::size_t;
    static constexpr std::size_t size() noexcept
    {
        return sizeof ... (Ints);
    }
};

template<class Sequence1, class Sequence2>
struct merge_and_renumber;

template<std::size_t... I1, std::size_t... I2>
struct merge_and_renumber<index_sequence<I1...>, index_sequence<I2...>>
    : index_sequence<I1..., (sizeof ... (I1) +I2) ...> {};

template<std::size_t N>
struct make_index_sequence
    : merge_and_renumber<typename make_index_sequence<N / 2>::type,
                         typename make_index_sequence<N - N / 2>::type> {};

template<> struct make_index_sequence<0> : index_sequence<> {};

template<> struct make_index_sequence<1> : index_sequence<0> {};

template<typename... Ts>
using index_sequence_for = make_index_sequence<sizeof ... (Ts)>;

/*
Implementation of two C++17 constructs: conjunction, negation. This is needed
to avoid evaluating all the traits in a condition

For example: not std::is_same<void, T>::value and has_value_type<T>::value
will not compile when T = void (on MSVC at least). Whereas
conjunction<negation<std::is_same<void, T>>, has_value_type<T>>::value will
stop evaluating if negation<...>::value == false

Please note that those constructs must be used with caution, since symbols can
become very long quickly (which can slow down compilation and cause MSVC
internal compiler errors). Only use it when you have to (see example ahead).
*/
template<class...> struct conjunction : std::true_type {};

template<class B1> struct conjunction<B1> : B1 {};

template<class B1, class... Bn>
struct conjunction<B1, Bn...> : std::conditional<bool(B1::value), conjunction<Bn...>, B1>::type {};

template<class B> struct negation : std::integral_constant<bool, not B::value> {};

// dispatch utility (taken from ranges-v3)
template<unsigned N> struct priority_tag : priority_tag<N - 1> {};

template<> struct priority_tag<0> {};

// has_/is_ functions //

// source: https://stackoverflow.com/a/37193089/4116453

template<typename T, typename = void>
struct is_complete_type : std::false_type {};

template<typename T>
struct is_complete_type<T, decltype(void(sizeof(T)))> : std::true_type {};

NLOHMANN_JSON_HAS_HELPER(mapped_type);
NLOHMANN_JSON_HAS_HELPER(key_type);
NLOHMANN_JSON_HAS_HELPER(value_type);
NLOHMANN_JSON_HAS_HELPER(iterator);

template<bool B, class RealType, class CompatibleObjectType>
struct is_compatible_object_type_impl : std::false_type {};

template<class RealType, class CompatibleObjectType>
struct is_compatible_object_type_impl<true, RealType, CompatibleObjectType>
{
    static constexpr auto value =
        std::is_constructible<typename RealType::key_type, typename CompatibleObjectType::key_type>::value and
        std::is_constructible<typename RealType::mapped_type,
                              typename CompatibleObjectType::mapped_type>::value;
};

template<class BasicJsonType, class CompatibleObjectType>
struct is_compatible_object_type
{
    static auto constexpr value = is_compatible_object_type_impl<
            conjunction<negation<std::is_same<void, CompatibleObjectType>>,
                        has_mapped_type<CompatibleObjectType>,
                        has_key_type<CompatibleObjectType>>::value,
            typename BasicJsonType::object_t, CompatibleObjectType>::value;
};

template<typename BasicJsonType, typename T>
struct is_basic_json_nested_type
{
    static auto constexpr value = std::is_same<T, typename BasicJsonType::iterator>::value or
        std::is_same<T, typename BasicJsonType::const_iterator>::value or
        std::is_same<T, typename BasicJsonType::reverse_iterator>::value or
        std::is_same<T, typename BasicJsonType::const_reverse_iterator>::value;
};

template<class BasicJsonType, class CompatibleArrayType>
struct is_compatible_array_type
{
    static auto constexpr value =
        conjunction<negation<std::is_same<void, CompatibleArrayType>>,
                    negation<is_compatible_object_type<
                                 BasicJsonType, CompatibleArrayType>>,
                    negation<std::is_constructible<typename BasicJsonType::string_t,
                                                   CompatibleArrayType>>,
                    negation<is_basic_json_nested_type<BasicJsonType, CompatibleArrayType>>,
                    has_value_type<CompatibleArrayType>,
                    has_iterator<CompatibleArrayType>>::value;
};

template<bool, typename, typename>
struct is_compatible_integer_type_impl : std::false_type {};

template<typename RealIntegerType, typename CompatibleNumberIntegerType>
struct is_compatible_integer_type_impl<true, RealIntegerType, CompatibleNumberIntegerType>
{
    // is there an assert somewhere on overflows?
    using RealLimits = std::numeric_limits<RealIntegerType>;
    using CompatibleLimits = std::numeric_limits<CompatibleNumberIntegerType>;

    static constexpr auto value =
        std::is_constructible<RealIntegerType, CompatibleNumberIntegerType>::value and
        CompatibleLimits::is_integer and
        RealLimits::is_signed == CompatibleLimits::is_signed;
};

template<typename RealIntegerType, typename CompatibleNumberIntegerType>
struct is_compatible_integer_type
{
    static constexpr auto value =
        is_compatible_integer_type_impl<
            std::is_integral<CompatibleNumberIntegerType>::value and
            not std::is_same<bool, CompatibleNumberIntegerType>::value,
            RealIntegerType, CompatibleNumberIntegerType>::value;
};

// trait checking if JSONSerializer<T>::from_json(json const&, udt&) exists
template<typename BasicJsonType, typename T>
struct has_from_json
{
private:
    // also check the return type of from_json
    template<typename U, typename = enable_if_t<std::is_same<void, decltype(uncvref_t<U>::from_json(
                                                                                std::declval<BasicJsonType>(),
                                                                                std::declval<T &>()))>::value>>
    static int detect(U &&);
    static void detect(...);

public:
    static constexpr bool value = std::is_integral<decltype(
                                                       detect(std::declval<typename BasicJsonType::template json_serializer<T,
                                                                                                                            void>>()))>
        ::value;
};

// This trait checks if JSONSerializer<T>::from_json(json const&) exists
// this overload is used for non-default-constructible user-defined-types
template<typename BasicJsonType, typename T>
struct has_non_default_from_json
{
private:
    template<
        typename U,
        typename = enable_if_t<std::is_same<
                                   T,
                                   decltype(uncvref_t<U>::from_json(std::declval<BasicJsonType>()))>::value>>
    static int detect(U &&);
    static void detect(...);

public:
    static constexpr bool value = std::is_integral<decltype(detect(
                                                                std::declval<typename BasicJsonType::template json_serializer<T,
                                                                                                                              void>>()))>
        ::value;
};

// This trait checks if BasicJsonType::json_serializer<T>::to_json exists
template<typename BasicJsonType, typename T>
struct has_to_json
{
private:
    template<typename U, typename = decltype(uncvref_t<U>::to_json(
                                                 std::declval<BasicJsonType &>(), std::declval<T>()))>
    static int detect(U &&);
    static void detect(...);

public:
    static constexpr bool value = std::is_integral<decltype(detect(
                                                                std::declval<typename BasicJsonType::template json_serializer<T,
                                                                                                                              void>>()))>
        ::value;
};

template<typename BasicJsonType, typename CompatibleCompleteType>
struct is_compatible_complete_type
{
    static constexpr bool value =
        not std::is_base_of<std::istream, CompatibleCompleteType>::value and
        not std::is_same<BasicJsonType, CompatibleCompleteType>::value and
        not is_basic_json_nested_type<BasicJsonType, CompatibleCompleteType>::value and
        has_to_json<BasicJsonType, CompatibleCompleteType>::value;
};

template<typename BasicJsonType, typename CompatibleType>
struct is_compatible_type
    : conjunction<is_complete_type<CompatibleType>,
                  is_compatible_complete_type<BasicJsonType, CompatibleType>>
{
};

// taken from ranges-v3
template<typename T>
struct static_const
{
    static constexpr T value {};
};

template<typename T>
constexpr T static_const<T>::value;
} // namespace detail
} // namespace nlohmann

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


#include <exception> // exception
#include <stdexcept> // runtime_error
#include <string> // to_string

namespace nlohmann
{
namespace detail
{
// exceptions //

class exception : public std::exception
{
public:
    const char *what() const noexcept override
    {
        return m.what();
    }

    const int id;

protected:
    exception(int id_, const char *what_arg) : id(id_), m(what_arg) {}

    static std::string name(const std::string &ename, int id_)
    {
        return "[json.exception." + ename + "." + std::to_string(id_) + "] ";
    }

private:
    std::runtime_error m;
};

class parse_error : public exception
{
public:
    static parse_error create(int id_, std::size_t byte_, const std::string &what_arg)
    {
        std::string w = exception::name("parse_error", id_) + "parse error" +
            (byte_ != 0 ? (" at " + std::to_string(byte_)) : "") +
            ": " + what_arg;
        return parse_error(id_, byte_, w.c_str());
    }

    const std::size_t byte;

private:
    parse_error(int id_, std::size_t byte_, const char *what_arg)
        : exception(id_, what_arg), byte(byte_) {}
};

class invalid_iterator : public exception
{
public:
    static invalid_iterator create(int id_, const std::string &what_arg)
    {
        std::string w = exception::name("invalid_iterator", id_) + what_arg;
        return invalid_iterator(id_, w.c_str());
    }

private:
    invalid_iterator(int id_, const char *what_arg)
        : exception(id_, what_arg) {}
};

class type_error : public exception
{
public:
    static type_error create(int id_, const std::string &what_arg)
    {
        std::string w = exception::name("type_error", id_) + what_arg;
        return type_error(id_, w.c_str());
    }

private:
    type_error(int id_, const char *what_arg) : exception(id_, what_arg) {}
};

class out_of_range : public exception
{
public:
    static out_of_range create(int id_, const std::string &what_arg)
    {
        std::string w = exception::name("out_of_range", id_) + what_arg;
        return out_of_range(id_, w.c_str());
    }

private:
    out_of_range(int id_, const char *what_arg) : exception(id_, what_arg) {}
};

class other_error : public exception
{
public:
    static other_error create(int id_, const std::string &what_arg)
    {
        std::string w = exception::name("other_error", id_) + what_arg;
        return other_error(id_, w.c_str());
    }

private:
    other_error(int id_, const char *what_arg) : exception(id_, what_arg) {}
};

} // namespace detail
} // namespace nlohmann

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


#include <array> // array
#include <ciso646> // and
#include <cstddef> // size_t
#include <cstdint> // uint8_t

namespace nlohmann
{
namespace detail
{
// JSON type enumeration //

enum class value_t : std::uint8_t
{
    null,             
    object,           
    array,            
    string,           
    boolean,          
    number_integer,   
    number_unsigned,  
    number_float,     
    discarded         
};

inline bool operator<(const value_t lhs, const value_t rhs) noexcept
{
    static constexpr std::array<std::uint8_t, 8> order = { {
                                                               0 /* null */, 3 /* object */, 4 /* array */,
                                                               5 /* string */,
                                                               1 /* boolean */, 2 /* integer */,
                                                               2 /* unsigned */, 2 /* float */
                                                           } };

    const auto l_index = static_cast<std::size_t>(lhs);
    const auto r_index = static_cast<std::size_t>(rhs);
    return l_index < order.size() and r_index < order.size() and order[l_index] < order[r_index];
}
} // namespace detail
} // namespace nlohmann

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


#include <algorithm> // transform
#include <array> // array
#include <ciso646> // and, not
#include <forward_list> // forward_list
#include <iterator> // inserter, front_inserter, end
#include <string> // string
#include <tuple> // tuple, make_tuple
#include <type_traits> // is_arithmetic, is_same, is_enum, underlying_type, is_convertible
#include <utility> // pair, declval
#include <valarray> // valarray

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

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

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

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


namespace nlohmann
{
namespace detail
{
// overloads for basic_json template parameters
template<typename BasicJsonType, typename ArithmeticType,
         enable_if_t<std::is_arithmetic<ArithmeticType>::value and
                     not std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
                     int> = 0>
void get_arithmetic_value(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;
    }

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

template<typename BasicJsonType>
void from_json(const BasicJsonType &j, typename BasicJsonType::boolean_t &b)
{
    if (JSON_UNLIKELY(not j.is_boolean())) {
        JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(j.type_name())));
    }

    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>
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...> {});
}

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 detail

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

// #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>


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<>
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, 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 };
}

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 detail

namespace
{
constexpr const auto &to_json = detail::static_const<detail::to_json_fn>::value;
} // namespace
} // namespace nlohmann

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


#include <algorithm> // min
#include <array> // array
#include <cassert> // assert
#include <cstddef> // size_t
#include <cstring> // strlen
#include <ios> // streamsize, streamoff, streampos
#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
{
// input adapters //

struct input_adapter_protocol
{
    virtual std::char_traits<char>::int_type get_character() = 0;
    virtual void unget_character() = 0;
    virtual ~input_adapter_protocol() = default;
};

using input_adapter_t = std::shared_ptr<input_adapter_protocol>;

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())
    {
        // skip byte order mark
        std::char_traits<char>::int_type c;
        if ((c = get_character()) == 0xEF) {
            if ((c = get_character()) == 0xBB) {
                if ((c = get_character()) == 0xBF) {
                    return; // Ignore BOM
                } else if (c != std::char_traits<char>::eof()) {
                    is.unget();
                }

                is.putback('\xBB');
            } else if (c != std::char_traits<char>::eof()) {
                is.unget();
            }

            is.putback('\xEF');
        } else if (c != std::char_traits<char>::eof()) {
            is.unget(); // no byte order mark; process as usual
        }
    }

    // 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();
    }

    void unget_character() override
    {
        sb.sungetc();  // is.unget() avoided for performance
    }

private:
    std::istream &is;
    std::streambuf &sb;
};

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), start(b)
    {
        // skip byte order mark
        if (l >= 3 and b[0] == '\xEF' and b[1] == '\xBB' and b[2] == '\xBF') {
            cursor += 3;
        }
    }

    // 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();
    }

    void unget_character() noexcept override
    {
        if (JSON_LIKELY(cursor > start)) {
            --cursor;
        }
    }

private:
    const char *cursor;
    const char *limit;
    const char *start;
};

class input_adapter
{
public:
    // native support

    input_adapter(std::istream &i)
        : ia(std::make_shared<input_stream_adapter>(i)) {}

    input_adapter(std::istream &&i)
        : ia(std::make_shared<input_stream_adapter>(i)) {}

    template<typename CharT,
             typename std::enable_if<
                 std::is_pointer<CharT>::value and
                 std::is_integral<typename std::remove_pointer<CharT>::type>::value and
                 sizeof(typename std::remove_pointer<CharT>::type) == 1,
                 int>::type = 0>
    input_adapter(CharT b, std::size_t l)
        : ia(std::make_shared<input_buffer_adapter>(reinterpret_cast<const char *>(b), l)) {}

    // derived support

    template<typename CharT,
             typename std::enable_if<
                 std::is_pointer<CharT>::value and
                 std::is_integral<typename std::remove_pointer<CharT>::type>::value and
                 sizeof(typename std::remove_pointer<CharT>::type) == 1,
                 int>::type = 0>
    input_adapter(CharT b)
        : input_adapter(reinterpret_cast<const char *>(b),
                        std::strlen(reinterpret_cast<const char *>(b))) {}

    template<class IteratorType,
             typename std::enable_if<
                 std::is_same<typename std::iterator_traits<IteratorType>::iterator_category,
                              std::random_access_iterator_tag>::value,
                 int>::type = 0>
    input_adapter(IteratorType first, IteratorType last)
    {
        // assertion to check that the iterator range is indeed contiguous,
        // see http://stackoverflow.com/a/35008842/266378 for more discussion
        assert(std::accumulate(
                   first, last, std::pair<bool, int>(true, 0),
                   [&first](std::pair<bool, int> res, decltype(*first) val) {
                    res.first &= (val == *(std::next(std::addressof(*first), res.second++)));
                    return res;
                }).first);

        // assertion to check that each element is 1 byte long
        static_assert(
            sizeof(typename std::iterator_traits<IteratorType>::value_type) == 1,
            "each element in the iterator range must have the size of 1 byte");

        const auto len = static_cast<size_t>(std::distance(first, last));
        if (JSON_LIKELY(len > 0)) {
            // there is at least one element: use the address of first
            ia = std::make_shared<input_buffer_adapter>(reinterpret_cast<const char *>(&(*first)), len);
        } else {
            // the address of first cannot be used: use nullptr
            ia = std::make_shared<input_buffer_adapter>(nullptr, len);
        }
    }

    template<class T, std::size_t N>
    input_adapter(T(&array)[N])
        : input_adapter(std::begin(array), std::end(array)) {}

    template<class ContiguousContainer, typename
             std::enable_if<not std::is_pointer<ContiguousContainer>::value and
                            std::is_base_of<std::random_access_iterator_tag,
                                            typename std::iterator_traits<decltype(std::begin(std::declval<ContiguousContainer const>()))>::iterator_category>::value,
                            int>::type = 0>
    input_adapter(const ContiguousContainer &c)
        : input_adapter(std::begin(c), std::end(c)) {}

    operator input_adapter_t()
    {
        return ia;
    }

private:
    input_adapter_t ia = nullptr;
};

} // namespace detail
} // namespace nlohmann

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


#include <clocale> // localeconv
#include <cstddef> // size_t
#include <cstdlib> // strtof, strtod, strtold, strtoll, strtoull
#include <initializer_list> // initializer_list
#include <ios> // hex, uppercase
#include <iomanip> // setw, setfill
#include <sstream> // stringstream
#include <string> // char_traits, string
#include <vector> // vector

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

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


namespace nlohmann
{
namespace detail
{
// lexer //

template<typename BasicJsonType>

class lexer
{
    using number_integer_t = typename BasicJsonType::number_integer_t;
    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
    using number_float_t = typename BasicJsonType::number_float_t;

public:
    enum class token_type
    {
        uninitialized,    
        literal_true,     
        literal_false,    
        literal_null,     
        value_string,     
        value_unsigned,   
        value_integer,    
        value_float,      
        begin_array,      
        begin_object,     
        end_array,        
        end_object,       
        name_separator,   
        value_separator,  
        parse_error,      
        end_of_input,     
        literal_or_value  
    };

    static const char *token_type_name(const token_type t) noexcept
    {
        switch (t) {
        case token_type::uninitialized:
            return "<uninitialized>";
        case token_type::literal_true:
            return "true literal";
        case token_type::literal_false:
            return "false literal";
        case token_type::literal_null:
            return "null literal";
        case token_type::value_string:
            return "string literal";
        case lexer::token_type::value_unsigned:
        case lexer::token_type::value_integer:
        case lexer::token_type::value_float:
            return "number literal";
        case token_type::begin_array:
            return "'['";
        case token_type::begin_object:
            return "'{'";
        case token_type::end_array:
            return "']'";
        case token_type::end_object:
            return "'}'";
        case token_type::name_separator:
            return "':'";
        case token_type::value_separator:
            return "','";
        case token_type::parse_error:
            return "<parse error>";
        case token_type::end_of_input:
            return "end of input";
        case token_type::literal_or_value:
            return "'[', '{', or a literal";
        default:     // catch non-enum values
            return "unknown token";     // LCOV_EXCL_LINE
        }
    }

    explicit lexer(detail::input_adapter_t adapter)
        : ia(std::move(adapter)), decimal_point_char(get_decimal_point()) {}

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

private:
    // locales

    static char get_decimal_point() noexcept
    {
        const auto loc = localeconv();
        assert(loc != nullptr);
        return (loc->decimal_point == nullptr) ? '.' : *(loc->decimal_point);
    }

    // scan functions

    int get_codepoint()
    {
        // this function only makes sense after reading `\u`
        assert(current == 'u');
        int codepoint = 0;

        const auto factors = { 12, 8, 4, 0 };
        for (const auto factor : factors) {
            get();

            if (current >= '0' and current <= '9') {
                codepoint += ((current - 0x30) << factor);
            } else if (current >= 'A' and current <= 'F') {
                codepoint += ((current - 0x37) << factor);
            } else if (current >= 'a' and current <= 'f') {
                codepoint += ((current - 0x57) << factor);
            } else {
                return -1;
            }
        }

        assert(0x0000 <= codepoint and codepoint <= 0xFFFF);
        return codepoint;
    }

    bool next_byte_in_range(std::initializer_list<int> ranges)
    {
        assert(ranges.size() == 2 or ranges.size() == 4 or ranges.size() == 6);
        add(current);

        for (auto range = ranges.begin(); range != ranges.end(); ++range) {
            get();
            if (JSON_LIKELY(*range <= current and current <= *(++range))) {
                add(current);
            } else {
                error_message = "invalid string: ill-formed UTF-8 byte";
                return false;
            }
        }

        return true;
    }

    token_type scan_string()
    {
        // reset token_buffer (ignore opening quote)
        reset();

        // we entered the function by reading an open quote
        assert(current == '\"');

        while (true) {
            // get next character
            switch (get()) {
            // end of file while parsing string
            case std::char_traits<char>::eof():
            {
                error_message = "invalid string: missing closing quote";
                return token_type::parse_error;
            }

            // closing quote
            case '\"':
            {
                return token_type::value_string;
            }

            // escapes
            case '\\':
            {
                switch (get()) {
                // quotation mark
                case '\"':
                    add('\"');
                    break;
                // reverse solidus
                case '\\':
                    add('\\');
                    break;
                // solidus
                case '/':
                    add('/');
                    break;
                // backspace
                case 'b':
                    add('\b');
                    break;
                // form feed
                case 'f':
                    add('\f');
                    break;
                // line feed
                case 'n':
                    add('\n');
                    break;
                // carriage return
                case 'r':
                    add('\r');
                    break;
                // tab
                case 't':
                    add('\t');
                    break;

                // unicode escapes
                case 'u':
                {
                    const int codepoint1 = get_codepoint();
                    int codepoint = codepoint1;         // start with codepoint1

                    if (JSON_UNLIKELY(codepoint1 == -1)) {
                        error_message = "invalid string: '\\u' must be followed by 4 hex digits";
                        return token_type::parse_error;
                    }

                    // check if code point is a high surrogate
                    if (0xD800 <= codepoint1 and codepoint1 <= 0xDBFF) {
                        // expect next \uxxxx entry
                        if (JSON_LIKELY(get() == '\\' and get() == 'u')) {
                            const int codepoint2 = get_codepoint();

                            if (JSON_UNLIKELY(codepoint2 == -1)) {
                                error_message = "invalid string: '\\u' must be followed by 4 hex digits";
                                return token_type::parse_error;
                            }

                            // check if codepoint2 is a low surrogate
                            if (JSON_LIKELY(0xDC00 <= codepoint2 and codepoint2 <= 0xDFFF)) {
                                // overwrite codepoint
                                codepoint =
                                    // high surrogate occupies the most significant 22 bits
                                    (codepoint1 << 10)
                                    // low surrogate occupies the least significant 15 bits
                                    + codepoint2
                                    // there is still the 0xD800, 0xDC00 and 0x10000 noise
                                    // in the result so we have to subtract with:
                                    // (0xD800 << 10) + DC00 - 0x10000 = 0x35FDC00
                                    - 0x35FDC00;
                            } else {
                                error_message =
                                    "invalid string: surrogate U+DC00..U+DFFF must be followed by U+DC00..U+DFFF";
                                return token_type::parse_error;
                            }
                        } else {
                            error_message =
                                "invalid string: surrogate U+DC00..U+DFFF must be followed by U+DC00..U+DFFF";
                            return token_type::parse_error;
                        }
                    } else {
                        if (JSON_UNLIKELY(0xDC00 <= codepoint1 and codepoint1 <= 0xDFFF)) {
                            error_message =
                                "invalid string: surrogate U+DC00..U+DFFF must follow U+D800..U+DBFF";
                            return token_type::parse_error;
                        }
                    }

                    // result of the above calculation yields a proper codepoint
                    assert(0x00 <= codepoint and codepoint <= 0x10FFFF);

                    // translate codepoint into bytes
                    if (codepoint < 0x80) {
                        // 1-byte characters: 0xxxxxxx (ASCII)
                        add(codepoint);
                    } else if (codepoint <= 0x7FF) {
                        // 2-byte characters: 110xxxxx 10xxxxxx
                        add(0xC0 | (codepoint >> 6));
                        add(0x80 | (codepoint & 0x3F));
                    } else if (codepoint <= 0xFFFF) {
                        // 3-byte characters: 1110xxxx 10xxxxxx 10xxxxxx
                        add(0xE0 | (codepoint >> 12));
                        add(0x80 | ((codepoint >> 6) & 0x3F));
                        add(0x80 | (codepoint & 0x3F));
                    } else {
                        // 4-byte characters: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
                        add(0xF0 | (codepoint >> 18));
                        add(0x80 | ((codepoint >> 12) & 0x3F));
                        add(0x80 | ((codepoint >> 6) & 0x3F));
                        add(0x80 | (codepoint & 0x3F));
                    }

                    break;
                }

                // other characters after escape
                default:
                    error_message = "invalid string: forbidden character after backslash";
                    return token_type::parse_error;
                }

                break;
            }

            // invalid control characters
            case 0x00:
            case 0x01:
            case 0x02:
            case 0x03:
            case 0x04:
            case 0x05:
            case 0x06:
            case 0x07:
            case 0x08:
            case 0x09:
            case 0x0A:
            case 0x0B:
            case 0x0C:
            case 0x0D:
            case 0x0E:
            case 0x0F:
            case 0x10:
            case 0x11:
            case 0x12:
            case 0x13:
            case 0x14:
            case 0x15:
            case 0x16:
            case 0x17:
            case 0x18:
            case 0x19:
            case 0x1A:
            case 0x1B:
            case 0x1C:
            case 0x1D:
            case 0x1E:
            case 0x1F:
            {
                error_message = "invalid string: control character must be escaped";
                return token_type::parse_error;
            }

            // U+0020..U+007F (except U+0022 (quote) and U+005C (backspace))
            case 0x20:
            case 0x21:
            case 0x23:
            case 0x24:
            case 0x25:
            case 0x26:
            case 0x27:
            case 0x28:
            case 0x29:
            case 0x2A:
            case 0x2B:
            case 0x2C:
            case 0x2D:
            case 0x2E:
            case 0x2F:
            case 0x30:
            case 0x31:
            case 0x32:
            case 0x33:
            case 0x34:
            case 0x35:
            case 0x36:
            case 0x37:
            case 0x38:
            case 0x39:
            case 0x3A:
            case 0x3B:
            case 0x3C:
            case 0x3D:
            case 0x3E:
            case 0x3F:
            case 0x40:
            case 0x41:
            case 0x42:
            case 0x43:
            case 0x44:
            case 0x45:
            case 0x46:
            case 0x47:
            case 0x48:
            case 0x49:
            case 0x4A:
            case 0x4B:
            case 0x4C:
            case 0x4D:
            case 0x4E:
            case 0x4F:
            case 0x50:
            case 0x51:
            case 0x52:
            case 0x53:
            case 0x54:
            case 0x55:
            case 0x56:
            case 0x57:
            case 0x58:
            case 0x59:
            case 0x5A:
            case 0x5B:
            case 0x5D:
            case 0x5E:
            case 0x5F:
            case 0x60:
            case 0x61:
            case 0x62:
            case 0x63:
            case 0x64:
            case 0x65:
            case 0x66:
            case 0x67:
            case 0x68:
            case 0x69:
            case 0x6A:
            case 0x6B:
            case 0x6C:
            case 0x6D:
            case 0x6E:
            case 0x6F:
            case 0x70:
            case 0x71:
            case 0x72:
            case 0x73:
            case 0x74:
            case 0x75:
            case 0x76:
            case 0x77:
            case 0x78:
            case 0x79:
            case 0x7A:
            case 0x7B:
            case 0x7C:
            case 0x7D:
            case 0x7E:
            case 0x7F:
            {
                add(current);
                break;
            }

            // U+0080..U+07FF: bytes C2..DF 80..BF
            case 0xC2:
            case 0xC3:
            case 0xC4:
            case 0xC5:
            case 0xC6:
            case 0xC7:
            case 0xC8:
            case 0xC9:
            case 0xCA:
            case 0xCB:
            case 0xCC:
            case 0xCD:
            case 0xCE:
            case 0xCF:
            case 0xD0:
            case 0xD1:
            case 0xD2:
            case 0xD3:
            case 0xD4:
            case 0xD5:
            case 0xD6:
            case 0xD7:
            case 0xD8:
            case 0xD9:
            case 0xDA:
            case 0xDB:
            case 0xDC:
            case 0xDD:
            case 0xDE:
            case 0xDF:
            {
                if (JSON_UNLIKELY(not next_byte_in_range({ 0x80, 0xBF }))) {
                    return token_type::parse_error;
                }

                break;
            }

            // U+0800..U+0FFF: bytes E0 A0..BF 80..BF
            case 0xE0:
            {
                if (JSON_UNLIKELY(not (next_byte_in_range({ 0xA0, 0xBF, 0x80, 0xBF })))) {
                    return token_type::parse_error;
                }

                break;
            }

            // U+1000..U+CFFF: bytes E1..EC 80..BF 80..BF
            // U+E000..U+FFFF: bytes EE..EF 80..BF 80..BF
            case 0xE1:
            case 0xE2:
            case 0xE3:
            case 0xE4:
            case 0xE5:
            case 0xE6:
            case 0xE7:
            case 0xE8:
            case 0xE9:
            case 0xEA:
            case 0xEB:
            case 0xEC:
            case 0xEE:
            case 0xEF:
            {
                if (JSON_UNLIKELY(not (next_byte_in_range({ 0x80, 0xBF, 0x80, 0xBF })))) {
                    return token_type::parse_error;
                }

                break;
            }

            // U+D000..U+D7FF: bytes ED 80..9F 80..BF
            case 0xED:
            {
                if (JSON_UNLIKELY(not (next_byte_in_range({ 0x80, 0x9F, 0x80, 0xBF })))) {
                    return token_type::parse_error;
                }

                break;
            }

            // U+10000..U+3FFFF F0 90..BF 80..BF 80..BF
            case 0xF0:
            {
                if (JSON_UNLIKELY(not (next_byte_in_range({ 0x90, 0xBF, 0x80, 0xBF, 0x80, 0xBF })))) {
                    return token_type::parse_error;
                }

                break;
            }

            // U+40000..U+FFFFF F1..F3 80..BF 80..BF 80..BF
            case 0xF1:
            case 0xF2:
            case 0xF3:
            {
                if (JSON_UNLIKELY(not (next_byte_in_range({ 0x80, 0xBF, 0x80, 0xBF, 0x80, 0xBF })))) {
                    return token_type::parse_error;
                }

                break;
            }

            // U+100000..U+10FFFF F4 80..8F 80..BF 80..BF
            case 0xF4:
            {
                if (JSON_UNLIKELY(not (next_byte_in_range({ 0x80, 0x8F, 0x80, 0xBF, 0x80, 0xBF })))) {
                    return token_type::parse_error;
                }

                break;
            }

            // remaining bytes (80..C1 and F5..FF) are ill-formed
            default:
            {
                error_message = "invalid string: ill-formed UTF-8 byte";
                return token_type::parse_error;
            }
            }
        }
    }

    static void strtof(float &f, const char *str, char **endptr) noexcept
    {
        f = std::strtof(str, endptr);
    }

    static void strtof(double &f, const char *str, char **endptr) noexcept
    {
        f = std::strtod(str, endptr);
    }

    static void strtof(long double &f, const char *str, char **endptr) noexcept
    {
        f = std::strtold(str, endptr);
    }

    token_type scan_number()
    {
        // reset token_buffer to store the number's bytes
        reset();

        // the type of the parsed number; initially set to unsigned; will be
        // changed if minus sign, decimal point or exponent is read
        token_type number_type = token_type::value_unsigned;

        // state (init): we just found out we need to scan a number
        switch (current) {
        case '-':
        {
            add(current);
            goto scan_number_minus;
        }

        case '0':
        {
            add(current);
            goto scan_number_zero;
        }

        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        {
            add(current);
            goto scan_number_any1;
        }

        default:
        {
            // all other characters are rejected outside scan_number()
            assert(false);     // LCOV_EXCL_LINE
        }
        }

    scan_number_minus:
        // state: we just parsed a leading minus sign
        number_type = token_type::value_integer;
        switch (get()) {
        case '0':
        {
            add(current);
            goto scan_number_zero;
        }

        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        {
            add(current);
            goto scan_number_any1;
        }

        default:
        {
            error_message = "invalid number; expected digit after '-'";
            return token_type::parse_error;
        }
        }

    scan_number_zero:
        // state: we just parse a zero (maybe with a leading minus sign)
        switch (get()) {
        case '.':
        {
            add(decimal_point_char);
            goto scan_number_decimal1;
        }

        case 'e':
        case 'E':
        {
            add(current);
            goto scan_number_exponent;
        }

        default:
            goto scan_number_done;
        }

    scan_number_any1:
        // state: we just parsed a number 0-9 (maybe with a leading minus sign)
        switch (get()) {
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        {
            add(current);
            goto scan_number_any1;
        }

        case '.':
        {
            add(decimal_point_char);
            goto scan_number_decimal1;
        }

        case 'e':
        case 'E':
        {
            add(current);
            goto scan_number_exponent;
        }

        default:
            goto scan_number_done;
        }

    scan_number_decimal1:
        // state: we just parsed a decimal point
        number_type = token_type::value_float;
        switch (get()) {
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        {
            add(current);
            goto scan_number_decimal2;
        }

        default:
        {
            error_message = "invalid number; expected digit after '.'";
            return token_type::parse_error;
        }
        }

    scan_number_decimal2:
        // we just parsed at least one number after a decimal point
        switch (get()) {
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        {
            add(current);
            goto scan_number_decimal2;
        }

        case 'e':
        case 'E':
        {
            add(current);
            goto scan_number_exponent;
        }

        default:
            goto scan_number_done;
        }

    scan_number_exponent:
        // we just parsed an exponent
        number_type = token_type::value_float;
        switch (get()) {
        case '+':
        case '-':
        {
            add(current);
            goto scan_number_sign;
        }

        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        {
            add(current);
            goto scan_number_any2;
        }

        default:
        {
            error_message =
                "invalid number; expected '+', '-', or digit after exponent";
            return token_type::parse_error;
        }
        }

    scan_number_sign:
        // we just parsed an exponent sign
        switch (get()) {
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        {
            add(current);
            goto scan_number_any2;
        }

        default:
        {
            error_message = "invalid number; expected digit after exponent sign";
            return token_type::parse_error;
        }
        }

    scan_number_any2:
        // we just parsed a number after the exponent or exponent sign
        switch (get()) {
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        {
            add(current);
            goto scan_number_any2;
        }

        default:
            goto scan_number_done;
        }

    scan_number_done:
        // unget the character after the number (we only read it to know that
        // we are done scanning a number)
        unget();

        char *endptr = nullptr;
        errno = 0;

        // try to parse integers first and fall back to floats
        if (number_type == token_type::value_unsigned) {
            const auto x = std::strtoull(token_buffer.data(), &endptr, 10);

            // we checked the number format before
            assert(endptr == token_buffer.data() + token_buffer.size());

            if (errno == 0) {
                value_unsigned = static_cast<number_unsigned_t>(x);
                if (value_unsigned == x) {
                    return token_type::value_unsigned;
                }
            }
        } else if (number_type == token_type::value_integer) {
            const auto x = std::strtoll(token_buffer.data(), &endptr, 10);

            // we checked the number format before
            assert(endptr == token_buffer.data() + token_buffer.size());

            if (errno == 0) {
                value_integer = static_cast<number_integer_t>(x);
                if (value_integer == x) {
                    return token_type::value_integer;
                }
            }
        }

        // this code is reached if we parse a floating-point number or if an
        // integer conversion above failed
        strtof(value_float, token_buffer.data(), &endptr);

        // we checked the number format before
        assert(endptr == token_buffer.data() + token_buffer.size());

        return token_type::value_float;
    }

    token_type scan_literal(const char *literal_text, const std::size_t length,
                            token_type return_type)
    {
        assert(current == literal_text[0]);
        for (std::size_t i = 1; i < length; ++i) {
            if (JSON_UNLIKELY(get() != literal_text[i])) {
                error_message = "invalid literal";
                return token_type::parse_error;
            }
        }

        return return_type;
    }

    // input management

    void reset() noexcept
    {
        token_buffer.clear();
        token_string.clear();
        token_string.push_back(std::char_traits<char>::to_char_type(current));
    }

    /*
    @brief get next character from the input

    This function provides the interface to the used input adapter. It does
    not throw in case the input reached EOF, but returns a
    `std::char_traits<char>::eof()` in that case.  Stores the scanned characters
    for use in error messages.

    @return character read from the input
    */
    std::char_traits<char>::int_type get()
    {
        ++chars_read;
        current = ia->get_character();
        if (JSON_LIKELY(current != std::char_traits<char>::eof())) {
            token_string.push_back(std::char_traits<char>::to_char_type(current));
        }

        return current;
    }

    void unget()
    {
        --chars_read;
        if (JSON_LIKELY(current != std::char_traits<char>::eof())) {
            ia->unget_character();
            assert(token_string.size() != 0);
            token_string.pop_back();
        }
    }

    void add(int c)
    {
        token_buffer.push_back(std::char_traits<char>::to_char_type(c));
    }

public:
    // value getters

    constexpr number_integer_t get_number_integer() const noexcept
    {
        return value_integer;
    }

    constexpr number_unsigned_t get_number_unsigned() const noexcept
    {
        return value_unsigned;
    }

    constexpr number_float_t get_number_float() const noexcept
    {
        return value_float;
    }

    std::string move_string()
    {
        return std::move(token_buffer);
    }

    // diagnostics

    constexpr std::size_t get_position() const noexcept
    {
        return chars_read;
    }

    std::string get_token_string() const
    {
        // escape control characters
        std::string result;
        for (const auto c : token_string) {
            if ('\x00' <= c and c <= '\x1F') {
                // escape control characters
                std::stringstream ss;
                ss << "<U+" << std::setw(4) << std::uppercase << std::setfill('0')
                   << std::hex << static_cast<int>(c) << ">";
                result += ss.str();
            } else {
                // add character as is
                result.push_back(c);
            }
        }

        return result;
    }

    constexpr const char *get_error_message() const noexcept
    {
        return error_message;
    }

    // actual scanner

    token_type scan()
    {
        // read next character and ignore whitespace
        do {
            get();
        } while (current == ' ' or current == '\t' or current == '\n' or current == '\r');

        switch (current) {
        // structural characters
        case '[':
            return token_type::begin_array;
        case ']':
            return token_type::end_array;
        case '{':
            return token_type::begin_object;
        case '}':
            return token_type::end_object;
        case ':':
            return token_type::name_separator;
        case ',':
            return token_type::value_separator;

        // literals
        case 't':
            return scan_literal("true", 4, token_type::literal_true);
        case 'f':
            return scan_literal("false", 5, token_type::literal_false);
        case 'n':
            return scan_literal("null", 4, token_type::literal_null);

        // string
        case '\"':
            return scan_string();

        // number
        case '-':
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
            return scan_number();

        // end of input (the null byte is needed when parsing from
        // string literals)
        case '\0':
        case std::char_traits<char>::eof():
            return token_type::end_of_input;

        // error
        default:
            error_message = "invalid literal";
            return token_type::parse_error;
        }
    }

private:
    detail::input_adapter_t ia = nullptr;

    std::char_traits<char>::int_type current = std::char_traits<char>::eof();

    std::size_t chars_read = 0;

    std::vector<char> token_string {};

    std::string token_buffer {};

    const char *error_message = "";

    // number values
    number_integer_t value_integer = 0;
    number_unsigned_t value_unsigned = 0;
    number_float_t value_float = 0;

    const char decimal_point_char = '.';
};

} // namespace detail
} // namespace nlohmann

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


#include <cassert> // assert
#include <cmath> // isfinite
#include <cstdint> // uint8_t
#include <functional> // function
#include <string> // string
#include <utility> // move

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

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

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

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

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


namespace nlohmann
{
namespace detail
{
// parser //

template<typename BasicJsonType>

class parser
{
    using number_integer_t = typename BasicJsonType::number_integer_t;
    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
    using number_float_t = typename BasicJsonType::number_float_t;
    using lexer_t = lexer<BasicJsonType>;
    using token_type = typename lexer_t::token_type;

public:
    enum class parse_event_t : uint8_t
    {
        object_start,
        object_end,
        array_start,
        array_end,
        key,
        value
    };

    using parser_callback_t =
        std::function<bool(int depth, parse_event_t event, BasicJsonType &parsed)>;

    explicit parser(detail::input_adapter_t adapter,
                    const parser_callback_t cb = nullptr,
                    const bool allow_exceptions_ = true)
        : callback(cb), m_lexer(adapter), allow_exceptions(allow_exceptions_)
    {}

    void parse(const bool strict, BasicJsonType &result)
    {
        // read first token
        get_token();

        parse_internal(true, result);
        result.assert_invariant();

        // in strict mode, input must be completely read
        if (strict) {
            get_token();
            expect(token_type::end_of_input);
        }

        // in case of an error, return discarded value
        if (errored) {
            result = value_t::discarded;
            return;
        }

        // set top-level value to null if it was discarded by the callback
        // function
        if (result.is_discarded()) {
            result = nullptr;
        }
    }

    bool accept(const bool strict = true)
    {
        // read first token
        get_token();

        if (not accept_internal()) {
            return false;
        }

        // strict => last token must be EOF
        return not strict or (get_token() == token_type::end_of_input);
    }

private:
    void parse_internal(bool keep, BasicJsonType &result)
    {
        // never parse after a parse error was detected
        assert(not errored);

        // start with a discarded value
        if (not result.is_discarded()) {
            result.m_value.destroy(result.m_type);
            result.m_type = value_t::discarded;
        }

        switch (last_token) {
        case token_type::begin_object:
        {
            if (keep) {
                if (callback) {
                    keep = callback(depth++, parse_event_t::object_start, result);
                }

                if (not callback or keep) {
                    // explicitly set result to object to cope with {}
                    result.m_type = value_t::object;
                    result.m_value = value_t::object;
                }
            }

            // read next token
            get_token();

            // closing } -> we are done
            if (last_token == token_type::end_object) {
                if (keep and callback and not callback(--depth, parse_event_t::object_end, result)) {
                    result.m_value.destroy(result.m_type);
                    result.m_type = value_t::discarded;
                }

                break;
            }

            // parse values
            std::string key;
            BasicJsonType value;
            while (true) {
                // store key
                if (not expect(token_type::value_string)) {
                    return;
                }

                key = m_lexer.move_string();

                bool keep_tag = false;
                if (keep) {
                    if (callback) {
                        BasicJsonType k(key);
                        keep_tag = callback(depth, parse_event_t::key, k);
                    } else {
                        keep_tag = true;
                    }
                }

                // parse separator (:)
                get_token();
                if (not expect(token_type::name_separator)) {
                    return;
                }

                // parse and add value
                get_token();
                value.m_value.destroy(value.m_type);
                value.m_type = value_t::discarded;
                parse_internal(keep, value);

                if (JSON_UNLIKELY(errored)) {
                    return;
                }

                if (keep and keep_tag and not value.is_discarded()) {
                    result.m_value.object->emplace(std::move(key), std::move(value));
                }

                // comma -> next value
                get_token();
                if (last_token == token_type::value_separator) {
                    get_token();
                    continue;
                }

                // closing }
                if (not expect(token_type::end_object)) {
                    return;
                }

                break;
            }

            if (keep and callback and not callback(--depth, parse_event_t::object_end, result)) {
                result.m_value.destroy(result.m_type);
                result.m_type = value_t::discarded;
            }

            break;
        }

        case token_type::begin_array:
        {
            if (keep) {
                if (callback) {
                    keep = callback(depth++, parse_event_t::array_start, result);
                }

                if (not callback or keep) {
                    // explicitly set result to array to cope with []
                    result.m_type = value_t::array;
                    result.m_value = value_t::array;
                }
            }

            // read next token
            get_token();

            // closing ] -> we are done
            if (last_token == token_type::end_array) {
                if (callback and not callback(--depth, parse_event_t::array_end, result)) {
                    result.m_value.destroy(result.m_type);
                    result.m_type = value_t::discarded;
                }

                break;
            }

            // parse values
            BasicJsonType value;
            while (true) {
                // parse value
                value.m_value.destroy(value.m_type);
                value.m_type = value_t::discarded;
                parse_internal(keep, value);

                if (JSON_UNLIKELY(errored)) {
                    return;
                }

                if (keep and not value.is_discarded()) {
                    result.m_value.array->push_back(std::move(value));
                }

                // comma -> next value
                get_token();
                if (last_token == token_type::value_separator) {
                    get_token();
                    continue;
                }

                // closing ]
                if (not expect(token_type::end_array)) {
                    return;
                }

                break;
            }

            if (keep and callback and not callback(--depth, parse_event_t::array_end, result)) {
                result.m_value.destroy(result.m_type);
                result.m_type = value_t::discarded;
            }

            break;
        }

        case token_type::literal_null:
        {
            result.m_type = value_t::null;
            break;
        }

        case token_type::value_string:
        {
            result.m_type = value_t::string;
            result.m_value = m_lexer.move_string();
            break;
        }

        case token_type::literal_true:
        {
            result.m_type = value_t::boolean;
            result.m_value = true;
            break;
        }

        case token_type::literal_false:
        {
            result.m_type = value_t::boolean;
            result.m_value = false;
            break;
        }

        case token_type::value_unsigned:
        {
            result.m_type = value_t::number_unsigned;
            result.m_value = m_lexer.get_number_unsigned();
            break;
        }

        case token_type::value_integer:
        {
            result.m_type = value_t::number_integer;
            result.m_value = m_lexer.get_number_integer();
            break;
        }

        case token_type::value_float:
        {
            result.m_type = value_t::number_float;
            result.m_value = m_lexer.get_number_float();

            // throw in case of infinity or NAN
            if (JSON_UNLIKELY(not std::isfinite(result.m_value.number_float))) {
                if (allow_exceptions) {
                    JSON_THROW(out_of_range::create(406, "number overflow parsing '" +
                                                    m_lexer.get_token_string() + "'"));
                }

                expect(token_type::uninitialized);
            }

            break;
        }

        case token_type::parse_error:
        {
            // using "uninitialized" to avoid "expected" message
            if (not expect(token_type::uninitialized)) {
                return;
            }

            break;     // LCOV_EXCL_LINE
        }

        default:
        {
            // the last token was unexpected; we expected a value
            if (not expect(token_type::literal_or_value)) {
                return;
            }

            break;     // LCOV_EXCL_LINE
        }
        }

        if (keep and callback and not callback(depth, parse_event_t::value, result)) {
            result.m_type = value_t::discarded;
        }
    }

    bool accept_internal()
    {
        switch (last_token) {
        case token_type::begin_object:
        {
            // read next token
            get_token();

            // closing } -> we are done
            if (last_token == token_type::end_object) {
                return true;
            }

            // parse values
            while (true) {
                // parse key
                if (last_token != token_type::value_string) {
                    return false;
                }

                // parse separator (:)
                get_token();
                if (last_token != token_type::name_separator) {
                    return false;
                }

                // parse value
                get_token();
                if (not accept_internal()) {
                    return false;
                }

                // comma -> next value
                get_token();
                if (last_token == token_type::value_separator) {
                    get_token();
                    continue;
                }

                // closing }
                return (last_token == token_type::end_object);
            }
        }

        case token_type::begin_array:
        {
            // read next token
            get_token();

            // closing ] -> we are done
            if (last_token == token_type::end_array) {
                return true;
            }

            // parse values
            while (true) {
                // parse value
                if (not accept_internal()) {
                    return false;
                }

                // comma -> next value
                get_token();
                if (last_token == token_type::value_separator) {
                    get_token();
                    continue;
                }

                // closing ]
                return (last_token == token_type::end_array);
            }
        }

        case token_type::value_float:
        {
            // reject infinity or NAN
            return std::isfinite(m_lexer.get_number_float());
        }

        case token_type::literal_false:
        case token_type::literal_null:
        case token_type::literal_true:
        case token_type::value_integer:
        case token_type::value_string:
        case token_type::value_unsigned:
            return true;

        default:     // the last token was unexpected
            return false;
        }
    }

    token_type get_token()
    {
        return (last_token = m_lexer.scan());
    }

    bool expect(token_type t)
    {
        if (JSON_UNLIKELY(t != last_token)) {
            errored = true;
            expected = t;
            if (allow_exceptions) {
                throw_exception();
            } else {
                return false;
            }
        }

        return true;
    }

    [[noreturn]] void throw_exception() const
    {
        std::string error_msg = "syntax error - ";
        if (last_token == token_type::parse_error) {
            error_msg += std::string(m_lexer.get_error_message()) + "; last read: '" +
                m_lexer.get_token_string() + "'";
        } else {
            error_msg += "unexpected " + std::string(lexer_t::token_type_name(last_token));
        }

        if (expected != token_type::uninitialized) {
            error_msg += "; expected " + std::string(lexer_t::token_type_name(expected));
        }

        JSON_THROW(parse_error::create(101, m_lexer.get_position(), error_msg));
    }

private:
    int depth = 0;
    const parser_callback_t callback = nullptr;
    token_type last_token = token_type::uninitialized;
    lexer_t m_lexer;
    bool errored = false;
    token_type expected = token_type::uninitialized;
    const bool allow_exceptions = true;
};

} // namespace detail
} // namespace nlohmann

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


#include <cstddef> // ptrdiff_t
#include <limits>  // numeric_limits

namespace nlohmann
{
namespace detail
{
/*
@brief an iterator for primitive JSON types

This class models an iterator for primitive JSON types (boolean, number,
string). It's only purpose is to allow the iterator/const_iterator classes
to "iterate" over primitive values. Internally, the iterator is modeled by
a `difference_type` variable. Value begin_value (`0`) models the begin,
end_value (`1`) models past the end.
*/

class primitive_iterator_t
{
private:
    using difference_type = std::ptrdiff_t;
    static constexpr difference_type begin_value = 0;
    static constexpr difference_type end_value = begin_value + 1;

    difference_type m_it = (std::numeric_limits<std::ptrdiff_t>::min)();

public:
    constexpr difference_type get_value() const noexcept
    {
        return m_it;
    }

    void set_begin() noexcept
    {
        m_it = begin_value;
    }

    void set_end() noexcept
    {
        m_it = end_value;
    }

    constexpr bool is_begin() const noexcept
    {
        return m_it == begin_value;
    }

    constexpr bool is_end() const noexcept
    {
        return m_it == end_value;
    }

    friend constexpr bool operator==(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
    {
        return lhs.m_it == rhs.m_it;
    }

    friend constexpr bool operator<(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
    {
        return lhs.m_it < rhs.m_it;
    }

    primitive_iterator_t operator+(difference_type n) noexcept
    {
        auto result = *this;
        result += n;
        return result;
    }

    friend constexpr difference_type operator-(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
    {
        return lhs.m_it - rhs.m_it;
    }

    primitive_iterator_t &operator++() noexcept
    {
        ++m_it;
        return *this;
    }

    primitive_iterator_t const operator++(int) noexcept
    {
        auto result = *this;
        m_it++;
        return result;
    }

    primitive_iterator_t &operator--() noexcept
    {
        --m_it;
        return *this;
    }

    primitive_iterator_t const operator--(int) noexcept
    {
        auto result = *this;
        m_it--;
        return result;
    }

    primitive_iterator_t &operator+=(difference_type n) noexcept
    {
        m_it += n;
        return *this;
    }

    primitive_iterator_t &operator-=(difference_type n) noexcept
    {
        m_it -= n;
        return *this;
    }
};

} // namespace detail
} // namespace nlohmann

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


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


namespace nlohmann
{
namespace detail
{
template<typename BasicJsonType> struct internal_iterator
{
    typename BasicJsonType::object_t::iterator object_iterator {};
    typename BasicJsonType::array_t::iterator array_iterator {};
    primitive_iterator_t primitive_iterator {};
};

} // namespace detail
} // namespace nlohmann

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


#include <ciso646> // not
#include <iterator> // iterator, random_access_iterator_tag, bidirectional_iterator_tag, advance, next
#include <type_traits> // conditional, is_const, remove_const

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

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

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

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

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

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


namespace nlohmann
{
namespace detail
{
// forward declare, to be able to friend it later on
template<typename IteratorType> class iteration_proxy;

template<typename BasicJsonType>

class iter_impl
{
    friend iter_impl<typename std::conditional<std::is_const<BasicJsonType>::value,
                                               typename std::remove_const<BasicJsonType>::type,
                                               const BasicJsonType>::type>;
    friend BasicJsonType;
    friend iteration_proxy<iter_impl>;

    using object_t = typename BasicJsonType::object_t;
    using array_t = typename BasicJsonType::array_t;
    // make sure BasicJsonType is basic_json or const basic_json
    static_assert(is_basic_json<typename std::remove_const<BasicJsonType>::type>::value,
                  "iter_impl only accepts (const) basic_json");

public:

    using iterator_category = std::bidirectional_iterator_tag;

    using value_type = typename BasicJsonType::value_type;
    using difference_type = typename BasicJsonType::difference_type;
    using pointer = typename std::conditional<std::is_const<BasicJsonType>::value,
                                              typename BasicJsonType::const_pointer,
                                              typename BasicJsonType::pointer>::type;
    using reference =
        typename std::conditional<std::is_const<BasicJsonType>::value,
                                  typename BasicJsonType::const_reference,
                                  typename BasicJsonType::reference>::type;

    iter_impl() = default;

    explicit iter_impl(pointer object) noexcept : m_object(object)
    {
        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
        {
            m_it.object_iterator = typename object_t::iterator();
            break;
        }

        case value_t::array:
        {
            m_it.array_iterator = typename array_t::iterator();
            break;
        }

        default:
        {
            m_it.primitive_iterator = primitive_iterator_t();
            break;
        }
        }
    }

    iter_impl(const iter_impl<typename std::remove_const<BasicJsonType>::type> &other) noexcept
        : m_object(other.m_object), m_it(other.m_it) {}

    iter_impl &operator=(const iter_impl<typename std::remove_const<BasicJsonType>::type> &other) noexcept
    {
        m_object = other.m_object;
        m_it = other.m_it;
        return *this;
    }

private:
    void set_begin() noexcept
    {
        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
        {
            m_it.object_iterator = m_object->m_value.object->begin();
            break;
        }

        case value_t::array:
        {
            m_it.array_iterator = m_object->m_value.array->begin();
            break;
        }

        case value_t::null:
        {
            // set to end so begin()==end() is true: null is empty
            m_it.primitive_iterator.set_end();
            break;
        }

        default:
        {
            m_it.primitive_iterator.set_begin();
            break;
        }
        }
    }

    void set_end() noexcept
    {
        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
        {
            m_it.object_iterator = m_object->m_value.object->end();
            break;
        }

        case value_t::array:
        {
            m_it.array_iterator = m_object->m_value.array->end();
            break;
        }

        default:
        {
            m_it.primitive_iterator.set_end();
            break;
        }
        }
    }

public:
    reference operator*() const
    {
        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
        {
            assert(m_it.object_iterator != m_object->m_value.object->end());
            return m_it.object_iterator->second;
        }

        case value_t::array:
        {
            assert(m_it.array_iterator != m_object->m_value.array->end());
            return *m_it.array_iterator;
        }

        case value_t::null:
            JSON_THROW(invalid_iterator::create(214, "cannot get value"));

        default:
        {
            if (JSON_LIKELY(m_it.primitive_iterator.is_begin())) {
                return *m_object;
            }

            JSON_THROW(invalid_iterator::create(214, "cannot get value"));
        }
        }
    }

    pointer operator->() const
    {
        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
        {
            assert(m_it.object_iterator != m_object->m_value.object->end());
            return &(m_it.object_iterator->second);
        }

        case value_t::array:
        {
            assert(m_it.array_iterator != m_object->m_value.array->end());
            return &*m_it.array_iterator;
        }

        default:
        {
            if (JSON_LIKELY(m_it.primitive_iterator.is_begin())) {
                return m_object;
            }

            JSON_THROW(invalid_iterator::create(214, "cannot get value"));
        }
        }
    }

    iter_impl const operator++(int)
    {
        auto result = *this;
        ++(*this);
        return result;
    }

    iter_impl &operator++()
    {
        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
        {
            std::advance(m_it.object_iterator, 1);
            break;
        }

        case value_t::array:
        {
            std::advance(m_it.array_iterator, 1);
            break;
        }

        default:
        {
            ++m_it.primitive_iterator;
            break;
        }
        }

        return *this;
    }

    iter_impl const operator--(int)
    {
        auto result = *this;
        --(*this);
        return result;
    }

    iter_impl &operator--()
    {
        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
        {
            std::advance(m_it.object_iterator, -1);
            break;
        }

        case value_t::array:
        {
            std::advance(m_it.array_iterator, -1);
            break;
        }

        default:
        {
            --m_it.primitive_iterator;
            break;
        }
        }

        return *this;
    }

    bool operator==(const iter_impl &other) const
    {
        // if objects are not the same, the comparison is undefined
        if (JSON_UNLIKELY(m_object != other.m_object)) {
            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
        }

        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
            return (m_it.object_iterator == other.m_it.object_iterator);

        case value_t::array:
            return (m_it.array_iterator == other.m_it.array_iterator);

        default:
            return (m_it.primitive_iterator == other.m_it.primitive_iterator);
        }
    }

    bool operator!=(const iter_impl &other) const
    {
        return not operator==(other);
    }

    bool operator<(const iter_impl &other) const
    {
        // if objects are not the same, the comparison is undefined
        if (JSON_UNLIKELY(m_object != other.m_object)) {
            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
        }

        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
            JSON_THROW(invalid_iterator::create(213, "cannot compare order of object iterators"));

        case value_t::array:
            return (m_it.array_iterator < other.m_it.array_iterator);

        default:
            return (m_it.primitive_iterator < other.m_it.primitive_iterator);
        }
    }

    bool operator<=(const iter_impl &other) const
    {
        return not other.operator<(*this);
    }

    bool operator>(const iter_impl &other) const
    {
        return not operator<=(other);
    }

    bool operator>=(const iter_impl &other) const
    {
        return not operator<(other);
    }

    iter_impl &operator+=(difference_type i)
    {
        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
            JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators"));

        case value_t::array:
        {
            std::advance(m_it.array_iterator, i);
            break;
        }

        default:
        {
            m_it.primitive_iterator += i;
            break;
        }
        }

        return *this;
    }

    iter_impl &operator-=(difference_type i)
    {
        return operator+=(-i);
    }

    iter_impl operator+(difference_type i) const
    {
        auto result = *this;
        result += i;
        return result;
    }

    friend iter_impl operator+(difference_type i, const iter_impl &it)
    {
        auto result = it;
        result += i;
        return result;
    }

    iter_impl operator-(difference_type i) const
    {
        auto result = *this;
        result -= i;
        return result;
    }

    difference_type operator-(const iter_impl &other) const
    {
        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
            JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators"));

        case value_t::array:
            return m_it.array_iterator - other.m_it.array_iterator;

        default:
            return m_it.primitive_iterator - other.m_it.primitive_iterator;
        }
    }

    reference operator[](difference_type n) const
    {
        assert(m_object != nullptr);

        switch (m_object->m_type) {
        case value_t::object:
            JSON_THROW(invalid_iterator::create(208, "cannot use operator[] for object iterators"));

        case value_t::array:
            return *std::next(m_it.array_iterator, n);

        case value_t::null:
            JSON_THROW(invalid_iterator::create(214, "cannot get value"));

        default:
        {
            if (JSON_LIKELY(m_it.primitive_iterator.get_value() == -n)) {
                return *m_object;
            }

            JSON_THROW(invalid_iterator::create(214, "cannot get value"));
        }
        }
    }

    typename object_t::key_type key() const
    {
        assert(m_object != nullptr);

        if (JSON_LIKELY(m_object->is_object())) {
            return m_it.object_iterator->first;
        }

        JSON_THROW(invalid_iterator::create(207, "cannot use key() for non-object iterators"));
    }

    reference value() const
    {
        return operator*();
    }

private:
    pointer m_object = nullptr;
    internal_iterator<typename std::remove_const<BasicJsonType>::type> m_it;
};

} // namespace detail
} // namespace nlohmann

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


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

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


namespace nlohmann
{
namespace detail
{
template<typename IteratorType> class iteration_proxy
{
private:
    class iteration_proxy_internal
    {
    private:
        IteratorType anchor;
        std::size_t array_index = 0;

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

        iteration_proxy_internal &operator*()
        {
            return *this;
        }

        iteration_proxy_internal &operator++()
        {
            ++anchor;
            ++array_index;

            return *this;
        }

        bool operator!=(const iteration_proxy_internal &o) const noexcept
        {
            return anchor != o.anchor;
        }

        std::string key() const
        {
            assert(anchor.m_object != nullptr);

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

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

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

        typename IteratorType::reference value() const
        {
            return anchor.value();
        }
    };

    typename IteratorType::reference container;

public:
    explicit iteration_proxy(typename IteratorType::reference cont) noexcept
        : container(cont) {}

    iteration_proxy_internal begin() noexcept
    {
        return iteration_proxy_internal(container.begin());
    }

    iteration_proxy_internal end() noexcept
    {
        return iteration_proxy_internal(container.end());
    }
};

} // namespace detail
} // namespace nlohmann

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


#include <cstddef> // ptrdiff_t
#include <iterator> // reverse_iterator
#include <utility> // declval

namespace nlohmann
{
namespace detail
{
// reverse_iterator //

template<typename Base>

class json_reverse_iterator : public std::reverse_iterator<Base>
{
public:
    using difference_type = std::ptrdiff_t;
    using base_iterator = std::reverse_iterator<Base>;
    using reference = typename Base::reference;

    json_reverse_iterator(const typename base_iterator::iterator_type &it) noexcept
        : base_iterator(it) {}

    json_reverse_iterator(const base_iterator &it) noexcept : base_iterator(it) {}

    json_reverse_iterator const operator++(int)
    {
        return static_cast<json_reverse_iterator>(base_iterator::operator++(1));
    }

    json_reverse_iterator &operator++()
    {
        return static_cast<json_reverse_iterator &>(base_iterator::operator++());
    }

    json_reverse_iterator const operator--(int)
    {
        return static_cast<json_reverse_iterator>(base_iterator::operator--(1));
    }

    json_reverse_iterator &operator--()
    {
        return static_cast<json_reverse_iterator &>(base_iterator::operator--());
    }

    json_reverse_iterator &operator+=(difference_type i)
    {
        return static_cast<json_reverse_iterator &>(base_iterator::operator+=(i));
    }

    json_reverse_iterator operator+(difference_type i) const
    {
        return static_cast<json_reverse_iterator>(base_iterator::operator+(i));
    }

    json_reverse_iterator operator-(difference_type i) const
    {
        return static_cast<json_reverse_iterator>(base_iterator::operator-(i));
    }

    difference_type operator-(const json_reverse_iterator &other) const
    {
        return base_iterator(*this) - base_iterator(other);
    }

    reference operator[](difference_type n) const
    {
        return *(this->operator+(n));
    }

    auto key() const->decltype(std::declval<Base>().key())
    {
        auto it = --this->base();
        return it.key();
    }

    reference value() const
    {
        auto it = --this->base();
        return it.operator*();
    }
};

} // namespace detail
} // namespace nlohmann

// #include <nlohmann/detail/output/output_adapters.hpp>


#include <algorithm> // copy
#include <cstddef> // size_t
#include <ios> // streamsize
#include <iterator> // back_inserter
#include <memory> // shared_ptr, make_shared
#include <ostream> // basic_ostream
#include <string> // basic_string
#include <vector> // vector

namespace nlohmann
{
namespace detail
{
template<typename CharType> struct output_adapter_protocol
{
    virtual void write_character(CharType c) = 0;
    virtual void write_characters(const CharType *s, std::size_t length) = 0;
    virtual ~output_adapter_protocol() = default;
};

template<typename CharType>
using output_adapter_t = std::shared_ptr<output_adapter_protocol<CharType>>;

template<typename CharType>
class output_vector_adapter : public output_adapter_protocol<CharType>
{
public:
    explicit output_vector_adapter(std::vector<CharType> &vec) : v(vec) {}

    void write_character(CharType c) override
    {
        v.push_back(c);
    }

    void write_characters(const CharType *s, std::size_t length) override
    {
        std::copy(s, s + length, std::back_inserter(v));
    }

private:
    std::vector<CharType> &v;
};

template<typename CharType>
class output_stream_adapter : public output_adapter_protocol<CharType>
{
public:
    explicit output_stream_adapter(std::basic_ostream<CharType> &s) : stream(s) {}

    void write_character(CharType c) override
    {
        stream.put(c);
    }

    void write_characters(const CharType *s, std::size_t length) override
    {
        stream.write(s, static_cast<std::streamsize>(length));
    }

private:
    std::basic_ostream<CharType> &stream;
};

template<typename CharType>
class output_string_adapter : public output_adapter_protocol<CharType>
{
public:
    explicit output_string_adapter(std::basic_string<CharType> &s) : str(s) {}

    void write_character(CharType c) override
    {
        str.push_back(c);
    }

    void write_characters(const CharType *s, std::size_t length) override
    {
        str.append(s, length);
    }

private:
    std::basic_string<CharType> &str;
};

template<typename CharType>

class output_adapter
{
public:
    output_adapter(std::vector<CharType> &vec)
        : oa(std::make_shared<output_vector_adapter<CharType>>(vec)) {}

    output_adapter(std::basic_ostream<CharType> &s)
        : oa(std::make_shared<output_stream_adapter<CharType>>(s)) {}

    output_adapter(std::basic_string<CharType> &s)
        : oa(std::make_shared<output_string_adapter<CharType>>(s)) {}

    operator output_adapter_t<CharType>()
    {
        return oa;
    }

private:
    output_adapter_t<CharType> oa = nullptr;
};

} // namespace detail
} // namespace nlohmann

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


#include <algorithm> // generate_n
#include <array> // array
#include <cassert> // assert
#include <cmath> // ldexp
#include <cstddef> // size_t
#include <cstdint> // uint8_t, uint16_t, uint32_t, uint64_t
#include <cstring> // memcpy
#include <iomanip> // setw, setfill
#include <ios> // hex
#include <iterator> // back_inserter
#include <limits> // numeric_limits
#include <sstream> // stringstream
#include <string> // char_traits, string
#include <utility> // make_pair, move

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

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

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

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


namespace nlohmann
{
namespace detail
{
// binary reader //

template<typename BasicJsonType>

class binary_reader
{
    using number_integer_t = typename BasicJsonType::number_integer_t;
    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
    using string_t = typename BasicJsonType::string_t;

public:
    explicit binary_reader(input_adapter_t adapter) : ia(std::move(adapter))
    {
        assert(ia);
    }

    BasicJsonType parse_cbor(const bool strict)
    {
        const auto res = parse_cbor_internal();
        if (strict) {
            get();
            expect_eof();
        }

        return res;
    }

    BasicJsonType parse_msgpack(const bool strict)
    {
        const auto res = parse_msgpack_internal();
        if (strict) {
            get();
            expect_eof();
        }

        return res;
    }

    BasicJsonType parse_ubjson(const bool strict)
    {
        const auto res = parse_ubjson_internal();
        if (strict) {
            get_ignore_noop();
            expect_eof();
        }

        return res;
    }

    static constexpr bool little_endianess(int num = 1) noexcept
    {
        return (*reinterpret_cast<char *>(&num) == 1);
    }

private:
    BasicJsonType parse_cbor_internal(const bool get_char = true)
    {
        switch (get_char ? get() : current) {
        // EOF
        case std::char_traits<char>::eof():
            JSON_THROW(parse_error::create(110, chars_read, "unexpected end of input"));

        // Integer 0x00..0x17 (0..23)
        case 0x00:
        case 0x01:
        case 0x02:
        case 0x03:
        case 0x04:
        case 0x05:
        case 0x06:
        case 0x07:
        case 0x08:
        case 0x09:
        case 0x0A:
        case 0x0B:
        case 0x0C:
        case 0x0D:
        case 0x0E:
        case 0x0F:
        case 0x10:
        case 0x11:
        case 0x12:
        case 0x13:
        case 0x14:
        case 0x15:
        case 0x16:
        case 0x17:
            return static_cast<number_unsigned_t>(current);

        case 0x18:     // Unsigned integer (one-byte uint8_t follows)
            return get_number<uint8_t>();

        case 0x19:     // Unsigned integer (two-byte uint16_t follows)
            return get_number<uint16_t>();

        case 0x1A:     // Unsigned integer (four-byte uint32_t follows)
            return get_number<uint32_t>();

        case 0x1B:     // Unsigned integer (eight-byte uint64_t follows)
            return get_number<uint64_t>();

        // Negative integer -1-0x00..-1-0x17 (-1..-24)
        case 0x20:
        case 0x21:
        case 0x22:
        case 0x23:
        case 0x24:
        case 0x25:
        case 0x26:
        case 0x27:
        case 0x28:
        case 0x29:
        case 0x2A:
        case 0x2B:
        case 0x2C:
        case 0x2D:
        case 0x2E:
        case 0x2F:
        case 0x30:
        case 0x31:
        case 0x32:
        case 0x33:
        case 0x34:
        case 0x35:
        case 0x36:
        case 0x37:
            return static_cast<int8_t>(0x20 - 1 - current);

        case 0x38:     // Negative integer (one-byte uint8_t follows)
        {
            return static_cast<number_integer_t>(-1) - get_number<uint8_t>();
        }

        case 0x39:     // Negative integer -1-n (two-byte uint16_t follows)
        {
            return static_cast<number_integer_t>(-1) - get_number<uint16_t>();
        }

        case 0x3A:     // Negative integer -1-n (four-byte uint32_t follows)
        {
            return static_cast<number_integer_t>(-1) - get_number<uint32_t>();
        }

        case 0x3B:     // Negative integer -1-n (eight-byte uint64_t follows)
        {
            return static_cast<number_integer_t>(-1) -
                   static_cast<number_integer_t>(get_number<uint64_t>());
        }

        // UTF-8 string (0x00..0x17 bytes follow)
        case 0x60:
        case 0x61:
        case 0x62:
        case 0x63:
        case 0x64:
        case 0x65:
        case 0x66:
        case 0x67:
        case 0x68:
        case 0x69:
        case 0x6A:
        case 0x6B:
        case 0x6C:
        case 0x6D:
        case 0x6E:
        case 0x6F:
        case 0x70:
        case 0x71:
        case 0x72:
        case 0x73:
        case 0x74:
        case 0x75:
        case 0x76:
        case 0x77:
        case 0x78:     // UTF-8 string (one-byte uint8_t for n follows)
        case 0x79:     // UTF-8 string (two-byte uint16_t for n follow)
        case 0x7A:     // UTF-8 string (four-byte uint32_t for n follow)
        case 0x7B:     // UTF-8 string (eight-byte uint64_t for n follow)
        case 0x7F:     // UTF-8 string (indefinite length)
        {
            return get_cbor_string();
        }

        // array (0x00..0x17 data items follow)
        case 0x80:
        case 0x81:
        case 0x82:
        case 0x83:
        case 0x84:
        case 0x85:
        case 0x86:
        case 0x87:
        case 0x88:
        case 0x89:
        case 0x8A:
        case 0x8B:
        case 0x8C:
        case 0x8D:
        case 0x8E:
        case 0x8F:
        case 0x90:
        case 0x91:
        case 0x92:
        case 0x93:
        case 0x94:
        case 0x95:
        case 0x96:
        case 0x97:
        {
            return get_cbor_array(current & 0x1F);
        }

        case 0x98:     // array (one-byte uint8_t for n follows)
        {
            return get_cbor_array(get_number<uint8_t>());
        }

        case 0x99:     // array (two-byte uint16_t for n follow)
        {
            return get_cbor_array(get_number<uint16_t>());
        }

        case 0x9A:     // array (four-byte uint32_t for n follow)
        {
            return get_cbor_array(get_number<uint32_t>());
        }

        case 0x9B:     // array (eight-byte uint64_t for n follow)
        {
            return get_cbor_array(get_number<uint64_t>());
        }

        case 0x9F:     // array (indefinite length)
        {
            BasicJsonType result = value_t::array;
            while (get() != 0xFF) {
                result.push_back(parse_cbor_internal(false));
            }

            return result;
        }

        // map (0x00..0x17 pairs of data items follow)
        case 0xA0:
        case 0xA1:
        case 0xA2:
        case 0xA3:
        case 0xA4:
        case 0xA5:
        case 0xA6:
        case 0xA7:
        case 0xA8:
        case 0xA9:
        case 0xAA:
        case 0xAB:
        case 0xAC:
        case 0xAD:
        case 0xAE:
        case 0xAF:
        case 0xB0:
        case 0xB1:
        case 0xB2:
        case 0xB3:
        case 0xB4:
        case 0xB5:
        case 0xB6:
        case 0xB7:
        {
            return get_cbor_object(current & 0x1F);
        }

        case 0xB8:     // map (one-byte uint8_t for n follows)
        {
            return get_cbor_object(get_number<uint8_t>());
        }

        case 0xB9:     // map (two-byte uint16_t for n follow)
        {
            return get_cbor_object(get_number<uint16_t>());
        }

        case 0xBA:     // map (four-byte uint32_t for n follow)
        {
            return get_cbor_object(get_number<uint32_t>());
        }

        case 0xBB:     // map (eight-byte uint64_t for n follow)
        {
            return get_cbor_object(get_number<uint64_t>());
        }

        case 0xBF:     // map (indefinite length)
        {
            BasicJsonType result = value_t::object;
            while (get() != 0xFF) {
                auto key = get_cbor_string();
                result[key] = parse_cbor_internal();
            }

            return result;
        }

        case 0xF4:     // false
        {
            return false;
        }

        case 0xF5:     // true
        {
            return true;
        }

        case 0xF6:     // null
        {
            return value_t::null;
        }

        case 0xF9:     // Half-Precision Float (two-byte IEEE 754)
        {
            const int byte1 = get();
            unexpect_eof();
            const int byte2 = get();
            unexpect_eof();

            // code from RFC 7049, Appendix D, Figure 3:
            // As half-precision floating-point numbers were only added
            // to IEEE 754 in 2008, today's programming platforms often
            // still only have limited support for them. It is very
            // easy to include at least decoding support for them even
            // without such support. An example of a small decoder for
            // half-precision floating-point numbers in the C language
            // is shown in Fig. 3.
            const int half = (byte1 << 8) + byte2;
            const int exp = (half >> 10) & 0x1F;
            const int mant = half & 0x3FF;
            double val;
            if (exp == 0) {
                val = std::ldexp(mant, -24);
            } else if (exp != 31) {
                val = std::ldexp(mant + 1024, exp - 25);
            } else {
                val = (mant == 0) ? std::numeric_limits<double>::infinity()
                                  : std::numeric_limits<double>::quiet_NaN();
            }

            return (half & 0x8000) != 0 ? -val : val;
        }

        case 0xFA:     // Single-Precision Float (four-byte IEEE 754)
        {
            return get_number<float>();
        }

        case 0xFB:     // Double-Precision Float (eight-byte IEEE 754)
        {
            return get_number<double>();
        }

        default:     // anything else (0xFF is handled inside the other types)
        {
            std::stringstream ss;
            ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
            JSON_THROW(parse_error::create(112, chars_read, "error reading CBOR; last byte: 0x" + ss.str()));
        }
        }
    }

    BasicJsonType parse_msgpack_internal()
    {
        switch (get()) {
        // EOF
        case std::char_traits<char>::eof():
            JSON_THROW(parse_error::create(110, chars_read, "unexpected end of input"));

        // positive fixint
        case 0x00:
        case 0x01:
        case 0x02:
        case 0x03:
        case 0x04:
        case 0x05:
        case 0x06:
        case 0x07:
        case 0x08:
        case 0x09:
        case 0x0A:
        case 0x0B:
        case 0x0C:
        case 0x0D:
        case 0x0E:
        case 0x0F:
        case 0x10:
        case 0x11:
        case 0x12:
        case 0x13:
        case 0x14:
        case 0x15:
        case 0x16:
        case 0x17:
        case 0x18:
        case 0x19:
        case 0x1A:
        case 0x1B:
        case 0x1C:
        case 0x1D:
        case 0x1E:
        case 0x1F:
        case 0x20:
        case 0x21:
        case 0x22:
        case 0x23:
        case 0x24:
        case 0x25:
        case 0x26:
        case 0x27:
        case 0x28:
        case 0x29:
        case 0x2A:
        case 0x2B:
        case 0x2C:
        case 0x2D:
        case 0x2E:
        case 0x2F:
        case 0x30:
        case 0x31:
        case 0x32:
        case 0x33:
        case 0x34:
        case 0x35:
        case 0x36:
        case 0x37:
        case 0x38:
        case 0x39:
        case 0x3A:
        case 0x3B:
        case 0x3C:
        case 0x3D:
        case 0x3E:
        case 0x3F:
        case 0x40:
        case 0x41:
        case 0x42:
        case 0x43:
        case 0x44:
        case 0x45:
        case 0x46:
        case 0x47:
        case 0x48:
        case 0x49:
        case 0x4A:
        case 0x4B:
        case 0x4C:
        case 0x4D:
        case 0x4E:
        case 0x4F:
        case 0x50:
        case 0x51:
        case 0x52:
        case 0x53:
        case 0x54:
        case 0x55:
        case 0x56:
        case 0x57:
        case 0x58:
        case 0x59:
        case 0x5A:
        case 0x5B:
        case 0x5C:
        case 0x5D:
        case 0x5E:
        case 0x5F:
        case 0x60:
        case 0x61:
        case 0x62:
        case 0x63:
        case 0x64:
        case 0x65:
        case 0x66:
        case 0x67:
        case 0x68:
        case 0x69:
        case 0x6A:
        case 0x6B:
        case 0x6C:
        case 0x6D:
        case 0x6E:
        case 0x6F:
        case 0x70:
        case 0x71:
        case 0x72:
        case 0x73:
        case 0x74:
        case 0x75:
        case 0x76:
        case 0x77:
        case 0x78:
        case 0x79:
        case 0x7A:
        case 0x7B:
        case 0x7C:
        case 0x7D:
        case 0x7E:
        case 0x7F:
            return static_cast<number_unsigned_t>(current);

        // fixmap
        case 0x80:
        case 0x81:
        case 0x82:
        case 0x83:
        case 0x84:
        case 0x85:
        case 0x86:
        case 0x87:
        case 0x88:
        case 0x89:
        case 0x8A:
        case 0x8B:
        case 0x8C:
        case 0x8D:
        case 0x8E:
        case 0x8F:
        {
            return get_msgpack_object(current & 0x0F);
        }

        // fixarray
        case 0x90:
        case 0x91:
        case 0x92:
        case 0x93:
        case 0x94:
        case 0x95:
        case 0x96:
        case 0x97:
        case 0x98:
        case 0x99:
        case 0x9A:
        case 0x9B:
        case 0x9C:
        case 0x9D:
        case 0x9E:
        case 0x9F:
        {
            return get_msgpack_array(current & 0x0F);
        }

        // fixstr
        case 0xA0:
        case 0xA1:
        case 0xA2:
        case 0xA3:
        case 0xA4:
        case 0xA5:
        case 0xA6:
        case 0xA7:
        case 0xA8:
        case 0xA9:
        case 0xAA:
        case 0xAB:
        case 0xAC:
        case 0xAD:
        case 0xAE:
        case 0xAF:
        case 0xB0:
        case 0xB1:
        case 0xB2:
        case 0xB3:
        case 0xB4:
        case 0xB5:
        case 0xB6:
        case 0xB7:
        case 0xB8:
        case 0xB9:
        case 0xBA:
        case 0xBB:
        case 0xBC:
        case 0xBD:
        case 0xBE:
        case 0xBF:
            return get_msgpack_string();

        case 0xC0:     // nil
            return value_t::null;

        case 0xC2:     // false
            return false;

        case 0xC3:     // true
            return true;

        case 0xCA:     // float 32
            return get_number<float>();

        case 0xCB:     // float 64
            return get_number<double>();

        case 0xCC:     // uint 8
            return get_number<uint8_t>();

        case 0xCD:     // uint 16
            return get_number<uint16_t>();

        case 0xCE:     // uint 32
            return get_number<uint32_t>();

        case 0xCF:     // uint 64
            return get_number<uint64_t>();

        case 0xD0:     // int 8
            return get_number<int8_t>();

        case 0xD1:     // int 16
            return get_number<int16_t>();

        case 0xD2:     // int 32
            return get_number<int32_t>();

        case 0xD3:     // int 64
            return get_number<int64_t>();

        case 0xD9:     // str 8
        case 0xDA:     // str 16
        case 0xDB:     // str 32
            return get_msgpack_string();

        case 0xDC:     // array 16
        {
            return get_msgpack_array(get_number<uint16_t>());
        }

        case 0xDD:     // array 32
        {
            return get_msgpack_array(get_number<uint32_t>());
        }

        case 0xDE:     // map 16
        {
            return get_msgpack_object(get_number<uint16_t>());
        }

        case 0xDF:     // map 32
        {
            return get_msgpack_object(get_number<uint32_t>());
        }

        // positive fixint
        case 0xE0:
        case 0xE1:
        case 0xE2:
        case 0xE3:
        case 0xE4:
        case 0xE5:
        case 0xE6:
        case 0xE7:
        case 0xE8:
        case 0xE9:
        case 0xEA:
        case 0xEB:
        case 0xEC:
        case 0xED:
        case 0xEE:
        case 0xEF:
        case 0xF0:
        case 0xF1:
        case 0xF2:
        case 0xF3:
        case 0xF4:
        case 0xF5:
        case 0xF6:
        case 0xF7:
        case 0xF8:
        case 0xF9:
        case 0xFA:
        case 0xFB:
        case 0xFC:
        case 0xFD:
        case 0xFE:
        case 0xFF:
            return static_cast<int8_t>(current);

        default:     // anything else
        {
            std::stringstream ss;
            ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
            JSON_THROW(parse_error::create(112, chars_read,
                                           "error reading MessagePack; last byte: 0x" + ss.str()));
        }
        }
    }

    BasicJsonType parse_ubjson_internal(const bool get_char = true)
    {
        return get_ubjson_value(get_char ? get_ignore_noop() : current);
    }

    int get()
    {
        ++chars_read;
        return (current = ia->get_character());
    }

    int get_ignore_noop()
    {
        do {
            get();
        } while (current == 'N');

        return current;
    }

    /*
    @brief read a number from the input

    @tparam NumberType the type of the number

    @return number of type @a NumberType

    @note This function needs to respect the system's endianess, because
          bytes in CBOR and MessagePack are stored in network order (big
          endian) and therefore need reordering on little endian systems.

    @throw parse_error.110 if input has less than `sizeof(NumberType)` bytes
    */
    template<typename NumberType> NumberType get_number()
    {
        // step 1: read input into array with system's byte order
        std::array<uint8_t, sizeof(NumberType)> vec;
        for (std::size_t i = 0; i < sizeof(NumberType); ++i) {
            get();
            unexpect_eof();

            // reverse byte order prior to conversion if necessary
            if (is_little_endian) {
                vec[sizeof(NumberType) - i - 1] = static_cast<uint8_t>(current);
            } else {
                vec[i] = static_cast<uint8_t>(current); // LCOV_EXCL_LINE
            }
        }

        // step 2: convert array into number of type T and return
        NumberType result;
        std::memcpy(&result, vec.data(), sizeof(NumberType));
        return result;
    }

    template<typename NumberType>
    string_t get_string(const NumberType len)
    {
        string_t result;
        std::generate_n(std::back_inserter(result), len, [this]() {
                    get();
                    unexpect_eof();
                    return static_cast<char>(current);
                });
        return result;
    }

    string_t get_cbor_string()
    {
        unexpect_eof();

        switch (current) {
        // UTF-8 string (0x00..0x17 bytes follow)
        case 0x60:
        case 0x61:
        case 0x62:
        case 0x63:
        case 0x64:
        case 0x65:
        case 0x66:
        case 0x67:
        case 0x68:
        case 0x69:
        case 0x6A:
        case 0x6B:
        case 0x6C:
        case 0x6D:
        case 0x6E:
        case 0x6F:
        case 0x70:
        case 0x71:
        case 0x72:
        case 0x73:
        case 0x74:
        case 0x75:
        case 0x76:
        case 0x77:
        {
            return get_string(current & 0x1F);
        }

        case 0x78:     // UTF-8 string (one-byte uint8_t for n follows)
        {
            return get_string(get_number<uint8_t>());
        }

        case 0x79:     // UTF-8 string (two-byte uint16_t for n follow)
        {
            return get_string(get_number<uint16_t>());
        }

        case 0x7A:     // UTF-8 string (four-byte uint32_t for n follow)
        {
            return get_string(get_number<uint32_t>());
        }

        case 0x7B:     // UTF-8 string (eight-byte uint64_t for n follow)
        {
            return get_string(get_number<uint64_t>());
        }

        case 0x7F:     // UTF-8 string (indefinite length)
        {
            string_t result;
            while (get() != 0xFF) {
                result.append(get_cbor_string());
            }

            return result;
        }

        default:
        {
            std::stringstream ss;
            ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
            JSON_THROW(parse_error::create(113, chars_read,
                                           "expected a CBOR string; last byte: 0x" + ss.str()));
        }
        }
    }

    template<typename NumberType>
    BasicJsonType get_cbor_array(const NumberType len)
    {
        BasicJsonType result = value_t::array;
        std::generate_n(std::back_inserter(*result.m_value.array), len, [this]() {
                    return parse_cbor_internal();
                });
        return result;
    }

    template<typename NumberType>
    BasicJsonType get_cbor_object(const NumberType len)
    {
        BasicJsonType result = value_t::object;
        std::generate_n(std::inserter(*result.m_value.object,
                                      result.m_value.object->end()),
                        len, [this]() {
                    get();
                    auto key = get_cbor_string();
                    auto val = parse_cbor_internal();
                    return std::make_pair(std::move(key), std::move(val));
                });
        return result;
    }

    string_t get_msgpack_string()
    {
        unexpect_eof();

        switch (current) {
        // fixstr
        case 0xA0:
        case 0xA1:
        case 0xA2:
        case 0xA3:
        case 0xA4:
        case 0xA5:
        case 0xA6:
        case 0xA7:
        case 0xA8:
        case 0xA9:
        case 0xAA:
        case 0xAB:
        case 0xAC:
        case 0xAD:
        case 0xAE:
        case 0xAF:
        case 0xB0:
        case 0xB1:
        case 0xB2:
        case 0xB3:
        case 0xB4:
        case 0xB5:
        case 0xB6:
        case 0xB7:
        case 0xB8:
        case 0xB9:
        case 0xBA:
        case 0xBB:
        case 0xBC:
        case 0xBD:
        case 0xBE:
        case 0xBF:
        {
            return get_string(current & 0x1F);
        }

        case 0xD9:     // str 8
        {
            return get_string(get_number<uint8_t>());
        }

        case 0xDA:     // str 16
        {
            return get_string(get_number<uint16_t>());
        }

        case 0xDB:     // str 32
        {
            return get_string(get_number<uint32_t>());
        }

        default:
        {
            std::stringstream ss;
            ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
            JSON_THROW(parse_error::create(113, chars_read,
                                           "expected a MessagePack string; last byte: 0x" + ss.str()));
        }
        }
    }

    template<typename NumberType>
    BasicJsonType get_msgpack_array(const NumberType len)
    {
        BasicJsonType result = value_t::array;
        std::generate_n(std::back_inserter(*result.m_value.array), len, [this]() {
                    return parse_msgpack_internal();
                });
        return result;
    }

    template<typename NumberType>
    BasicJsonType get_msgpack_object(const NumberType len)
    {
        BasicJsonType result = value_t::object;
        std::generate_n(std::inserter(*result.m_value.object,
                                      result.m_value.object->end()),
                        len, [this]() {
                    get();
                    auto key = get_msgpack_string();
                    auto val = parse_msgpack_internal();
                    return std::make_pair(std::move(key), std::move(val));
                });
        return result;
    }

    string_t get_ubjson_string(const bool get_char = true)
    {
        if (get_char) {
            get();  // TODO: may we ignore N here?
        }

        unexpect_eof();

        switch (current) {
        case 'U':
            return get_string(get_number<uint8_t>());
        case 'i':
            return get_string(get_number<int8_t>());
        case 'I':
            return get_string(get_number<int16_t>());
        case 'l':
            return get_string(get_number<int32_t>());
        case 'L':
            return get_string(get_number<int64_t>());
        default:
            std::stringstream ss;
            ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
            JSON_THROW(parse_error::create(113, chars_read,
                                           "expected a UBJSON string; last byte: 0x" + ss.str()));
        }
    }

    std::pair<std::size_t, int> get_ubjson_size_type()
    {
        std::size_t sz = string_t::npos;
        int tc = 0;

        get_ignore_noop();

        if (current == '$') {
            tc = get();  // must not ignore 'N', because 'N' maybe the type
            unexpect_eof();

            get_ignore_noop();
            if (current != '#') {
                std::stringstream ss;
                ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
                JSON_THROW(parse_error::create(112, chars_read,
                                               "expected '#' after UBJSON type information; last byte: 0x" +
                                               ss.str()));
            }

            sz = parse_ubjson_internal();
        } else if (current == '#') {
            sz = parse_ubjson_internal();
        }

        return std::make_pair(sz, tc);
    }

    BasicJsonType get_ubjson_value(const int prefix)
    {
        switch (prefix) {
        case std::char_traits<char>::eof():      // EOF
            JSON_THROW(parse_error::create(110, chars_read, "unexpected end of input"));

        case 'T':      // true
            return true;
        case 'F':      // false
            return false;

        case 'Z':      // null
            return nullptr;

        case 'U':
            return get_number<uint8_t>();
        case 'i':
            return get_number<int8_t>();
        case 'I':
            return get_number<int16_t>();
        case 'l':
            return get_number<int32_t>();
        case 'L':
            return get_number<int64_t>();
        case 'd':
            return get_number<float>();
        case 'D':
            return get_number<double>();

        case 'C':      // char
        {
            get();
            unexpect_eof();
            if (JSON_UNLIKELY(current > 127)) {
                std::stringstream ss;
                ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
                JSON_THROW(parse_error::create(113, chars_read,
                                               "byte after 'C' must be in range 0x00..0x7F; last byte: 0x" +
                                               ss.str()));
            }

            return string_t(1, static_cast<char>(current));
        }

        case 'S':      // string
            return get_ubjson_string();

        case '[':      // array
            return get_ubjson_array();

        case '{':      // object
            return get_ubjson_object();

        default:     // anything else
            std::stringstream ss;
            ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
            JSON_THROW(parse_error::create(112, chars_read,
                                           "error reading UBJSON; last byte: 0x" + ss.str()));
        }
    }

    BasicJsonType get_ubjson_array()
    {
        BasicJsonType result = value_t::array;
        const auto size_and_type = get_ubjson_size_type();

        if (size_and_type.first != string_t::npos) {
            if (JSON_UNLIKELY(size_and_type.first > result.max_size())) {
                JSON_THROW(out_of_range::create(408,
                                                "excessive array size: " + std::to_string(
                                                    size_and_type.first)));
            }

            if (size_and_type.second != 0) {
                if (size_and_type.second != 'N') {
                    std::generate_n(std::back_inserter(*result.m_value.array),
                                    size_and_type.first, [this, size_and_type]() {
                                return get_ubjson_value(size_and_type.second);
                            });
                }
            } else {
                std::generate_n(std::back_inserter(*result.m_value.array),
                                size_and_type.first, [this]() {
                            return parse_ubjson_internal();
                        });
            }
        } else {
            while (current != ']') {
                result.push_back(parse_ubjson_internal(false));
                get_ignore_noop();
            }
        }

        return result;
    }

    BasicJsonType get_ubjson_object()
    {
        BasicJsonType result = value_t::object;
        const auto size_and_type = get_ubjson_size_type();

        if (size_and_type.first != string_t::npos) {
            if (JSON_UNLIKELY(size_and_type.first > result.max_size())) {
                JSON_THROW(out_of_range::create(408,
                                                "excessive object size: " +
                                                std::to_string(size_and_type.first)));
            }

            if (size_and_type.second != 0) {
                std::generate_n(std::inserter(*result.m_value.object,
                                              result.m_value.object->end()),
                                size_and_type.first, [this, size_and_type]() {
                            auto key = get_ubjson_string();
                            auto val = get_ubjson_value(size_and_type.second);
                            return std::make_pair(std::move(key), std::move(val));
                        });
            } else {
                std::generate_n(std::inserter(*result.m_value.object,
                                              result.m_value.object->end()),
                                size_and_type.first, [this]() {
                            auto key = get_ubjson_string();
                            auto val = parse_ubjson_internal();
                            return std::make_pair(std::move(key), std::move(val));
                        });
            }
        } else {
            while (current != '}') {
                auto key = get_ubjson_string(false);
                result[std::move(key)] = parse_ubjson_internal();
                get_ignore_noop();
            }
        }

        return result;
    }

    void expect_eof() const
    {
        if (JSON_UNLIKELY(current != std::char_traits<char>::eof())) {
            JSON_THROW(parse_error::create(110, chars_read, "expected end of input"));
        }
    }

    void unexpect_eof() const
    {
        if (JSON_UNLIKELY(current == std::char_traits<char>::eof())) {
            JSON_THROW(parse_error::create(110, chars_read, "unexpected end of input"));
        }
    }

private:
    input_adapter_t ia = nullptr;

    int current = std::char_traits<char>::eof();

    std::size_t chars_read = 0;

    const bool is_little_endian = little_endianess();
};

} // namespace detail
} // namespace nlohmann

// #include <nlohmann/detail/output/binary_writer.hpp>


#include <algorithm> // reverse
#include <array> // array
#include <cstdint> // uint8_t, uint16_t, uint32_t, uint64_t
#include <cstring> // memcpy
#include <limits> // numeric_limits

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

// #include <nlohmann/detail/output/output_adapters.hpp>


namespace nlohmann
{
namespace detail
{
// binary writer //

template<typename BasicJsonType, typename CharType>

class binary_writer
{
public:
    explicit binary_writer(output_adapter_t<CharType> adapter) : oa(adapter)
    {
        assert(oa);
    }

    void write_cbor(const BasicJsonType &j)
    {
        switch (j.type()) {
        case value_t::null:
        {
            oa->write_character(static_cast<CharType>(0xF6));
            break;
        }

        case value_t::boolean:
        {
            oa->write_character(j.m_value.boolean
                                ? static_cast<CharType>(0xF5)
                                : static_cast<CharType>(0xF4));
            break;
        }

        case value_t::number_integer:
        {
            if (j.m_value.number_integer >= 0) {
                // CBOR does not differentiate between positive signed
                // integers and unsigned integers. Therefore, we used the
                // code from the value_t::number_unsigned case here.
                if (j.m_value.number_integer <= 0x17) {
                    write_number(static_cast<uint8_t>(j.m_value.number_integer));
                } else if (j.m_value.number_integer <= (std::numeric_limits<uint8_t>::max)()) {
                    oa->write_character(static_cast<CharType>(0x18));
                    write_number(static_cast<uint8_t>(j.m_value.number_integer));
                } else if (j.m_value.number_integer <= (std::numeric_limits<uint16_t>::max)()) {
                    oa->write_character(static_cast<CharType>(0x19));
                    write_number(static_cast<uint16_t>(j.m_value.number_integer));
                } else if (j.m_value.number_integer <= (std::numeric_limits<uint32_t>::max)()) {
                    oa->write_character(static_cast<CharType>(0x1A));
                    write_number(static_cast<uint32_t>(j.m_value.number_integer));
                } else {
                    oa->write_character(static_cast<CharType>(0x1B));
                    write_number(static_cast<uint64_t>(j.m_value.number_integer));
                }
            } else {
                // The conversions below encode the sign in the first
                // byte, and the value is converted to a positive number.
                const auto positive_number = -1 - j.m_value.number_integer;
                if (j.m_value.number_integer >= -24) {
                    write_number(static_cast<uint8_t>(0x20 + positive_number));
                } else if (positive_number <= (std::numeric_limits<uint8_t>::max)()) {
                    oa->write_character(static_cast<CharType>(0x38));
                    write_number(static_cast<uint8_t>(positive_number));
                } else if (positive_number <= (std::numeric_limits<uint16_t>::max)()) {
                    oa->write_character(static_cast<CharType>(0x39));
                    write_number(static_cast<uint16_t>(positive_number));
                } else if (positive_number <= (std::numeric_limits<uint32_t>::max)()) {
                    oa->write_character(static_cast<CharType>(0x3A));
                    write_number(static_cast<uint32_t>(positive_number));
                } else {
                    oa->write_character(static_cast<CharType>(0x3B));
                    write_number(static_cast<uint64_t>(positive_number));
                }
            }

            break;
        }

        case value_t::number_unsigned:
        {
            if (j.m_value.number_unsigned <= 0x17) {
                write_number(static_cast<uint8_t>(j.m_value.number_unsigned));
            } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)()) {
                oa->write_character(static_cast<CharType>(0x18));
                write_number(static_cast<uint8_t>(j.m_value.number_unsigned));
            } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)()) {
                oa->write_character(static_cast<CharType>(0x19));
                write_number(static_cast<uint16_t>(j.m_value.number_unsigned));
            } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)()) {
                oa->write_character(static_cast<CharType>(0x1A));
                write_number(static_cast<uint32_t>(j.m_value.number_unsigned));
            } else {
                oa->write_character(static_cast<CharType>(0x1B));
                write_number(static_cast<uint64_t>(j.m_value.number_unsigned));
            }

            break;
        }

        case value_t::number_float:     // Double-Precision Float
        {
            oa->write_character(static_cast<CharType>(0xFB));
            write_number(j.m_value.number_float);
            break;
        }

        case value_t::string:
        {
            // step 1: write control byte and the string length
            const auto N = j.m_value.string->size();
            if (N <= 0x17) {
                write_number(static_cast<uint8_t>(0x60 + N));
            } else if (N <= (std::numeric_limits<uint8_t>::max)()) {
                oa->write_character(static_cast<CharType>(0x78));
                write_number(static_cast<uint8_t>(N));
            } else if (N <= (std::numeric_limits<uint16_t>::max)()) {
                oa->write_character(static_cast<CharType>(0x79));
                write_number(static_cast<uint16_t>(N));
            } else if (N <= (std::numeric_limits<uint32_t>::max)()) {
                oa->write_character(static_cast<CharType>(0x7A));
                write_number(static_cast<uint32_t>(N));
            }
            // LCOV_EXCL_START
            else if (N <= (std::numeric_limits<uint64_t>::max)()) {
                oa->write_character(static_cast<CharType>(0x7B));
                write_number(static_cast<uint64_t>(N));
            }

            // LCOV_EXCL_STOP

            // step 2: write the string
            oa->write_characters(
                reinterpret_cast<const CharType *>(j.m_value.string->c_str()),
                j.m_value.string->size());
            break;
        }

        case value_t::array:
        {
            // step 1: write control byte and the array size
            const auto N = j.m_value.array->size();
            if (N <= 0x17) {
                write_number(static_cast<uint8_t>(0x80 + N));
            } else if (N <= (std::numeric_limits<uint8_t>::max)()) {
                oa->write_character(static_cast<CharType>(0x98));
                write_number(static_cast<uint8_t>(N));
            } else if (N <= (std::numeric_limits<uint16_t>::max)()) {
                oa->write_character(static_cast<CharType>(0x99));
                write_number(static_cast<uint16_t>(N));
            } else if (N <= (std::numeric_limits<uint32_t>::max)()) {
                oa->write_character(static_cast<CharType>(0x9A));
                write_number(static_cast<uint32_t>(N));
            }
            // LCOV_EXCL_START
            else if (N <= (std::numeric_limits<uint64_t>::max)()) {
                oa->write_character(static_cast<CharType>(0x9B));
                write_number(static_cast<uint64_t>(N));
            }

            // LCOV_EXCL_STOP

            // step 2: write each element
            for (const auto &el : *j.m_value.array) {
                write_cbor(el);
            }

            break;
        }

        case value_t::object:
        {
            // step 1: write control byte and the object size
            const auto N = j.m_value.object->size();
            if (N <= 0x17) {
                write_number(static_cast<uint8_t>(0xA0 + N));
            } else if (N <= (std::numeric_limits<uint8_t>::max)()) {
                oa->write_character(static_cast<CharType>(0xB8));
                write_number(static_cast<uint8_t>(N));
            } else if (N <= (std::numeric_limits<uint16_t>::max)()) {
                oa->write_character(static_cast<CharType>(0xB9));
                write_number(static_cast<uint16_t>(N));
            } else if (N <= (std::numeric_limits<uint32_t>::max)()) {
                oa->write_character(static_cast<CharType>(0xBA));
                write_number(static_cast<uint32_t>(N));
            }
            // LCOV_EXCL_START
            else if (N <= (std::numeric_limits<uint64_t>::max)()) {
                oa->write_character(static_cast<CharType>(0xBB));
                write_number(static_cast<uint64_t>(N));
            }

            // LCOV_EXCL_STOP

            // step 2: write each element
            for (const auto &el : *j.m_value.object) {
                write_cbor(el.first);
                write_cbor(el.second);
            }

            break;
        }

        default:
            break;
        }
    }

    void write_msgpack(const BasicJsonType &j)
    {
        switch (j.type()) {
        case value_t::null:     // nil
        {
            oa->write_character(static_cast<CharType>(0xC0));
            break;
        }

        case value_t::boolean:     // true and false
        {
            oa->write_character(j.m_value.boolean
                                ? static_cast<CharType>(0xC3)
                                : static_cast<CharType>(0xC2));
            break;
        }

        case value_t::number_integer:
        {
            if (j.m_value.number_integer >= 0) {
                // MessagePack does not differentiate between positive
                // signed integers and unsigned integers. Therefore, we used
                // the code from the value_t::number_unsigned case here.
                if (j.m_value.number_unsigned < 128) {
                    // positive fixnum
                    write_number(static_cast<uint8_t>(j.m_value.number_integer));
                } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)()) {
                    // uint 8
                    oa->write_character(static_cast<CharType>(0xCC));
                    write_number(static_cast<uint8_t>(j.m_value.number_integer));
                } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)()) {
                    // uint 16
                    oa->write_character(static_cast<CharType>(0xCD));
                    write_number(static_cast<uint16_t>(j.m_value.number_integer));
                } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)()) {
                    // uint 32
                    oa->write_character(static_cast<CharType>(0xCE));
                    write_number(static_cast<uint32_t>(j.m_value.number_integer));
                } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint64_t>::max)()) {
                    // uint 64
                    oa->write_character(static_cast<CharType>(0xCF));
                    write_number(static_cast<uint64_t>(j.m_value.number_integer));
                }
            } else {
                if (j.m_value.number_integer >= -32) {
                    // negative fixnum
                    write_number(static_cast<int8_t>(j.m_value.number_integer));
                } else if (j.m_value.number_integer >= (std::numeric_limits<int8_t>::min)() and
                           j.m_value.number_integer <= (std::numeric_limits<int8_t>::max)()) {
                    // int 8
                    oa->write_character(static_cast<CharType>(0xD0));
                    write_number(static_cast<int8_t>(j.m_value.number_integer));
                } else if (j.m_value.number_integer >= (std::numeric_limits<int16_t>::min)() and
                           j.m_value.number_integer <= (std::numeric_limits<int16_t>::max)()) {
                    // int 16
                    oa->write_character(static_cast<CharType>(0xD1));
                    write_number(static_cast<int16_t>(j.m_value.number_integer));
                } else if (j.m_value.number_integer >= (std::numeric_limits<int32_t>::min)() and
                           j.m_value.number_integer <= (std::numeric_limits<int32_t>::max)()) {
                    // int 32
                    oa->write_character(static_cast<CharType>(0xD2));
                    write_number(static_cast<int32_t>(j.m_value.number_integer));
                } else if (j.m_value.number_integer >= (std::numeric_limits<int64_t>::min)() and
                           j.m_value.number_integer <= (std::numeric_limits<int64_t>::max)()) {
                    // int 64
                    oa->write_character(static_cast<CharType>(0xD3));
                    write_number(static_cast<int64_t>(j.m_value.number_integer));
                }
            }

            break;
        }

        case value_t::number_unsigned:
        {
            if (j.m_value.number_unsigned < 128) {
                // positive fixnum
                write_number(static_cast<uint8_t>(j.m_value.number_integer));
            } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)()) {
                // uint 8
                oa->write_character(static_cast<CharType>(0xCC));
                write_number(static_cast<uint8_t>(j.m_value.number_integer));
            } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)()) {
                // uint 16
                oa->write_character(static_cast<CharType>(0xCD));
                write_number(static_cast<uint16_t>(j.m_value.number_integer));
            } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)()) {
                // uint 32
                oa->write_character(static_cast<CharType>(0xCE));
                write_number(static_cast<uint32_t>(j.m_value.number_integer));
            } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint64_t>::max)()) {
                // uint 64
                oa->write_character(static_cast<CharType>(0xCF));
                write_number(static_cast<uint64_t>(j.m_value.number_integer));
            }

            break;
        }

        case value_t::number_float:     // float 64
        {
            oa->write_character(static_cast<CharType>(0xCB));
            write_number(j.m_value.number_float);
            break;
        }

        case value_t::string:
        {
            // step 1: write control byte and the string length
            const auto N = j.m_value.string->size();
            if (N <= 31) {
                // fixstr
                write_number(static_cast<uint8_t>(0xA0 | N));
            } else if (N <= (std::numeric_limits<uint8_t>::max)()) {
                // str 8
                oa->write_character(static_cast<CharType>(0xD9));
                write_number(static_cast<uint8_t>(N));
            } else if (N <= (std::numeric_limits<uint16_t>::max)()) {
                // str 16
                oa->write_character(static_cast<CharType>(0xDA));
                write_number(static_cast<uint16_t>(N));
            } else if (N <= (std::numeric_limits<uint32_t>::max)()) {
                // str 32
                oa->write_character(static_cast<CharType>(0xDB));
                write_number(static_cast<uint32_t>(N));
            }

            // step 2: write the string
            oa->write_characters(
                reinterpret_cast<const CharType *>(j.m_value.string->c_str()),
                j.m_value.string->size());
            break;
        }

        case value_t::array:
        {
            // step 1: write control byte and the array size
            const auto N = j.m_value.array->size();
            if (N <= 15) {
                // fixarray
                write_number(static_cast<uint8_t>(0x90 | N));
            } else if (N <= (std::numeric_limits<uint16_t>::max)()) {
                // array 16
                oa->write_character(static_cast<CharType>(0xDC));
                write_number(static_cast<uint16_t>(N));
            } else if (N <= (std::numeric_limits<uint32_t>::max)()) {
                // array 32
                oa->write_character(static_cast<CharType>(0xDD));
                write_number(static_cast<uint32_t>(N));
            }

            // step 2: write each element
            for (const auto &el : *j.m_value.array) {
                write_msgpack(el);
            }

            break;
        }

        case value_t::object:
        {
            // step 1: write control byte and the object size
            const auto N = j.m_value.object->size();
            if (N <= 15) {
                // fixmap
                write_number(static_cast<uint8_t>(0x80 | (N & 0xF)));
            } else if (N <= (std::numeric_limits<uint16_t>::max)()) {
                // map 16
                oa->write_character(static_cast<CharType>(0xDE));
                write_number(static_cast<uint16_t>(N));
            } else if (N <= (std::numeric_limits<uint32_t>::max)()) {
                // map 32
                oa->write_character(static_cast<CharType>(0xDF));
                write_number(static_cast<uint32_t>(N));
            }

            // step 2: write each element
            for (const auto &el : *j.m_value.object) {
                write_msgpack(el.first);
                write_msgpack(el.second);
            }

            break;
        }

        default:
            break;
        }
    }

    void write_ubjson(const BasicJsonType &j, const bool use_count,
                      const bool use_type, const bool add_prefix = true)
    {
        switch (j.type()) {
        case value_t::null:
        {
            if (add_prefix) {
                oa->write_character(static_cast<CharType>('Z'));
            }

            break;
        }

        case value_t::boolean:
        {
            if (add_prefix)
                oa->write_character(j.m_value.boolean
                                    ? static_cast<CharType>('T')
                                    : static_cast<CharType>('F'));

            break;
        }

        case value_t::number_integer:
        {
            write_number_with_ubjson_prefix(j.m_value.number_integer, add_prefix);
            break;
        }

        case value_t::number_unsigned:
        {
            write_number_with_ubjson_prefix(j.m_value.number_unsigned, add_prefix);
            break;
        }

        case value_t::number_float:
        {
            write_number_with_ubjson_prefix(j.m_value.number_float, add_prefix);
            break;
        }

        case value_t::string:
        {
            if (add_prefix) {
                oa->write_character(static_cast<CharType>('S'));
            }

            write_number_with_ubjson_prefix(j.m_value.string->size(), true);
            oa->write_characters(
                reinterpret_cast<const CharType *>(j.m_value.string->c_str()),
                j.m_value.string->size());
            break;
        }

        case value_t::array:
        {
            if (add_prefix) {
                oa->write_character(static_cast<CharType>('['));
            }

            bool prefix_required = true;
            if (use_type and not j.m_value.array->empty()) {
                assert(use_count);
                const char first_prefix = ubjson_prefix(j.front());
                const bool same_prefix = std::all_of(j.begin() + 1, j.end(),
                                                     [this, first_prefix](const BasicJsonType &v) {
                                return ubjson_prefix(v) == first_prefix;
                            });

                if (same_prefix) {
                    prefix_required = false;
                    oa->write_character(static_cast<CharType>('$'));
                    oa->write_character(static_cast<CharType>(first_prefix));
                }
            }

            if (use_count) {
                oa->write_character(static_cast<CharType>('#'));
                write_number_with_ubjson_prefix(j.m_value.array->size(), true);
            }

            for (const auto &el : *j.m_value.array) {
                write_ubjson(el, use_count, use_type, prefix_required);
            }

            if (not use_count) {
                oa->write_character(static_cast<CharType>(']'));
            }

            break;
        }

        case value_t::object:
        {
            if (add_prefix) {
                oa->write_character(static_cast<CharType>('{'));
            }

            bool prefix_required = true;
            if (use_type and not j.m_value.object->empty()) {
                assert(use_count);
                const char first_prefix = ubjson_prefix(j.front());
                const bool same_prefix = std::all_of(j.begin(), j.end(),
                                                     [this, first_prefix](const BasicJsonType &v) {
                                return ubjson_prefix(v) == first_prefix;
                            });

                if (same_prefix) {
                    prefix_required = false;
                    oa->write_character(static_cast<CharType>('$'));
                    oa->write_character(static_cast<CharType>(first_prefix));
                }
            }

            if (use_count) {
                oa->write_character(static_cast<CharType>('#'));
                write_number_with_ubjson_prefix(j.m_value.object->size(), true);
            }

            for (const auto &el : *j.m_value.object) {
                write_number_with_ubjson_prefix(el.first.size(), true);
                oa->write_characters(
                    reinterpret_cast<const CharType *>(el.first.c_str()),
                    el.first.size());
                write_ubjson(el.second, use_count, use_type, prefix_required);
            }

            if (not use_count) {
                oa->write_character(static_cast<CharType>('}'));
            }

            break;
        }

        default:
            break;
        }
    }

private:
    /*
    @brief write a number to output input

    @param[in] n number of type @a NumberType
    @tparam NumberType the type of the number

    @note This function needs to respect the system's endianess, because bytes
          in CBOR, MessagePack, and UBJSON are stored in network order (big
          endian) and therefore need reordering on little endian systems.
    */
    template<typename NumberType>
    void write_number(const NumberType n)
    {
        // step 1: write number to array of length NumberType
        std::array<CharType, sizeof(NumberType)> vec;
        std::memcpy(vec.data(), &n, sizeof(NumberType));

        // step 2: write array to output (with possible reordering)
        if (is_little_endian) {
            // reverse byte order prior to conversion if necessary
            std::reverse(vec.begin(), vec.end());
        }

        oa->write_characters(vec.data(), sizeof(NumberType));
    }

    template<typename NumberType>
    void write_number_with_ubjson_prefix(const NumberType n,
                                         const bool add_prefix)
    {
        if (std::is_floating_point<NumberType>::value) {
            if (add_prefix) {
                oa->write_character(static_cast<CharType>('D'));  // float64
            }

            write_number(n);
        } else if (std::is_unsigned<NumberType>::value) {
            if (n <= (std::numeric_limits<int8_t>::max)()) {
                if (add_prefix) {
                    oa->write_character(static_cast<CharType>('i'));  // int8
                }

                write_number(static_cast<uint8_t>(n));
            } else if (n <= (std::numeric_limits<uint8_t>::max)()) {
                if (add_prefix) {
                    oa->write_character(static_cast<CharType>('U'));  // uint8
                }

                write_number(static_cast<uint8_t>(n));
            } else if (n <= (std::numeric_limits<int16_t>::max)()) {
                if (add_prefix) {
                    oa->write_character(static_cast<CharType>('I'));  // int16
                }

                write_number(static_cast<int16_t>(n));
            } else if (n <= (std::numeric_limits<int32_t>::max)()) {
                if (add_prefix) {
                    oa->write_character(static_cast<CharType>('l'));  // int32
                }

                write_number(static_cast<int32_t>(n));
            } else if (n <= (std::numeric_limits<int64_t>::max)()) {
                if (add_prefix) {
                    oa->write_character(static_cast<CharType>('L'));  // int64
                }

                write_number(static_cast<int64_t>(n));
            } else {
                JSON_THROW(out_of_range::create(407, "number overflow serializing " + std::to_string(n)));
            }
        } else {
            if ((std::numeric_limits<int8_t>::min)() <= n and n <= (std::numeric_limits<int8_t>::max)()) {
                if (add_prefix) {
                    oa->write_character(static_cast<CharType>('i'));  // int8
                }

                write_number(static_cast<int8_t>(n));
            } else if ((std::numeric_limits<uint8_t>::min)() <= n and n <=
                       (std::numeric_limits<uint8_t>::max)()) {
                if (add_prefix) {
                    oa->write_character(static_cast<CharType>('U'));  // uint8
                }

                write_number(static_cast<uint8_t>(n));
            } else if ((std::numeric_limits<int16_t>::min)() <= n and n <=
                       (std::numeric_limits<int16_t>::max)()) {
                if (add_prefix) {
                    oa->write_character(static_cast<CharType>('I'));  // int16
                }

                write_number(static_cast<int16_t>(n));
            } else if ((std::numeric_limits<int32_t>::min)() <= n and n <=
                       (std::numeric_limits<int32_t>::max)()) {
                if (add_prefix) {
                    oa->write_character(static_cast<CharType>('l'));  // int32
                }

                write_number(static_cast<int32_t>(n));
            } else if ((std::numeric_limits<int64_t>::min)() <= n and n <=
                       (std::numeric_limits<int64_t>::max)()) {
                if (add_prefix) {
                    oa->write_character(static_cast<CharType>('L'));  // int64
                }

                write_number(static_cast<int64_t>(n));
            }
            // LCOV_EXCL_START
            else {
                JSON_THROW(out_of_range::create(407, "number overflow serializing " + std::to_string(n)));
            }

            // LCOV_EXCL_STOP
        }
    }

    char ubjson_prefix(const BasicJsonType &j) const noexcept
    {
        switch (j.type()) {
        case value_t::null:
            return 'Z';

        case value_t::boolean:
            return j.m_value.boolean ? 'T' : 'F';

        case value_t::number_integer:
        {
            if ((std::numeric_limits<int8_t>::min)() <=
                j.m_value.number_integer and j.m_value.number_integer <=
                (std::numeric_limits<int8_t>::max)()) {
                return 'i';
            } else if ((std::numeric_limits<uint8_t>::min)() <=
                       j.m_value.number_integer and j.m_value.number_integer <=
                       (std::numeric_limits<uint8_t>::max)()) {
                return 'U';
            } else if ((std::numeric_limits<int16_t>::min)() <=
                       j.m_value.number_integer and j.m_value.number_integer <=
                       (std::numeric_limits<int16_t>::max)()) {
                return 'I';
            } else if ((std::numeric_limits<int32_t>::min)() <=
                       j.m_value.number_integer and j.m_value.number_integer <=
                       (std::numeric_limits<int32_t>::max)()) {
                return 'l';
            } else {  // no check and assume int64_t (see note above)
                return 'L';
            }
        }

        case value_t::number_unsigned:
        {
            if (j.m_value.number_unsigned <= (std::numeric_limits<int8_t>::max)()) {
                return 'i';
            } else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)()) {
                return 'U';
            } else if (j.m_value.number_unsigned <= (std::numeric_limits<int16_t>::max)()) {
                return 'I';
            } else if (j.m_value.number_unsigned <= (std::numeric_limits<int32_t>::max)()) {
                return 'l';
            } else {  // no check and assume int64_t (see note above)
                return 'L';
            }
        }

        case value_t::number_float:
            return 'D';

        case value_t::string:
            return 'S';

        case value_t::array:
            return '[';

        case value_t::object:
            return '{';

        default:      // discarded values
            return 'N';
        }
    }

private:
    const bool is_little_endian = binary_reader<BasicJsonType>::little_endianess();

    output_adapter_t<CharType> oa = nullptr;
};

} // namespace detail
} // namespace nlohmann

// #include <nlohmann/detail/output/serializer.hpp>


#include <algorithm> // reverse, remove, fill, find, none_of
#include <array> // array
#include <cassert> // assert
#include <ciso646> // and, or
#include <clocale> // localeconv, lconv
#include <cmath> // labs, isfinite, isnan, signbit
#include <cstddef> // size_t, ptrdiff_t
#include <cstdint> // uint8_t
#include <cstdio> // snprintf
#include <iomanip> // setfill
#include <iterator> // next
#include <limits> // numeric_limits
#include <string> // string
#include <sstream> // stringstream
#include <type_traits> // is_same

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

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


#include <cassert> // assert
#include <ciso646> // or, and, not
#include <cmath>   // signbit, isfinite
#include <cstdint> // intN_t, uintN_t
#include <cstring> // memcpy, memmove

namespace nlohmann
{
namespace detail
{

namespace dtoa_impl
{

template<typename Target, typename Source>
Target reinterpret_bits(const Source source)
{
    static_assert(sizeof(Target) == sizeof(Source), "size mismatch");

    Target target;
    std::memcpy(&target, &source, sizeof(Source));
    return target;
}

struct diyfp // f * 2^e
{
    static constexpr int kPrecision = 64; // = q

    uint64_t f;
    int e;

    constexpr diyfp() noexcept : f(0), e(0) {}
    constexpr diyfp(uint64_t f_, int e_) noexcept : f(f_), e(e_) {}

    static diyfp sub(const diyfp &x, const diyfp &y) noexcept
    {
        assert(x.e == y.e);
        assert(x.f >= y.f);

        return diyfp(x.f - y.f, x.e);
    }

    static diyfp mul(const diyfp &x, const diyfp &y) noexcept
    {
        static_assert(kPrecision == 64, "internal error");

        // Computes:
        //  f = round((x.f * y.f) / 2^q)
        //  e = x.e + y.e + q

        // Emulate the 64-bit * 64-bit multiplication:
        //
        // p = u * v
        //   = (u_lo + 2^32 u_hi) (v_lo + 2^32 v_hi)
        //   = (u_lo v_lo         ) + 2^32 ((u_lo v_hi         ) + (u_hi v_lo         )) + 2^64 (u_hi v_hi         )
        //   = (p0                ) + 2^32 ((p1                ) + (p2                )) + 2^64 (p3                )
        //   = (p0_lo + 2^32 p0_hi) + 2^32 ((p1_lo + 2^32 p1_hi) + (p2_lo + 2^32 p2_hi)) + 2^64 (p3                )
        //   = (p0_lo             ) + 2^32 (p0_hi + p1_lo + p2_lo                      ) + 2^64 (p1_hi + p2_hi + p3)
        //   = (p0_lo             ) + 2^32 (Q                                          ) + 2^64 (H                 )
        //   = (p0_lo             ) + 2^32 (Q_lo + 2^32 Q_hi                           ) + 2^64 (H                 )
        //
        // (Since Q might be larger than 2^32 - 1)
        //
        //   = (p0_lo + 2^32 Q_lo) + 2^64 (Q_hi + H)
        //
        // (Q_hi + H does not overflow a 64-bit int)
        //
        //   = p_lo + 2^64 p_hi

        const uint64_t u_lo = x.f & 0xFFFFFFFF;
        const uint64_t u_hi = x.f >> 32;
        const uint64_t v_lo = y.f & 0xFFFFFFFF;
        const uint64_t v_hi = y.f >> 32;

        const uint64_t p0 = u_lo * v_lo;
        const uint64_t p1 = u_lo * v_hi;
        const uint64_t p2 = u_hi * v_lo;
        const uint64_t p3 = u_hi * v_hi;

        const uint64_t p0_hi = p0 >> 32;
        const uint64_t p1_lo = p1 & 0xFFFFFFFF;
        const uint64_t p1_hi = p1 >> 32;
        const uint64_t p2_lo = p2 & 0xFFFFFFFF;
        const uint64_t p2_hi = p2 >> 32;

        uint64_t Q = p0_hi + p1_lo + p2_lo;

        // The full product might now be computed as
        //
        // p_hi = p3 + p2_hi + p1_hi + (Q >> 32)
        // p_lo = p0_lo + (Q << 32)
        //
        // But in this particular case here, the full p_lo is not required.
        // Effectively we only need to add the highest bit in p_lo to p_hi (and
        // Q_hi + 1 does not overflow).

        Q += uint64_t { 1 } << (64 - 32 - 1); // round, ties up

        const uint64_t h = p3 + p2_hi + p1_hi + (Q >> 32);

        return diyfp(h, x.e + y.e + 64);
    }

    static diyfp normalize(diyfp x) noexcept
    {
        assert(x.f != 0);

        while ((x.f >> 63) == 0) {
            x.f <<= 1;
            x.e--;
        }

        return x;
    }

    static diyfp normalize_to(const diyfp &x, const int target_exponent) noexcept
    {
        const int delta = x.e - target_exponent;

        assert(delta >= 0);
        assert(((x.f << delta) >> delta) == x.f);

        return diyfp(x.f << delta, target_exponent);
    }
};

struct boundaries
{
    diyfp w;
    diyfp minus;
    diyfp plus;
};

template<typename FloatType>
boundaries compute_boundaries(FloatType value)
{
    assert(std::isfinite(value));
    assert(value > 0);

    // Convert the IEEE representation into a diyfp.
    //
    // If v is denormal:
    //      value = 0.F * 2^(1 - bias) = (          F) * 2^(1 - bias - (p-1))
    // If v is normalized:
    //      value = 1.F * 2^(E - bias) = (2^(p-1) + F) * 2^(E - bias - (p-1))

    static_assert(std::numeric_limits<FloatType>::is_iec559,
                  "internal error: dtoa_short requires an IEEE-754 floating-point implementation");

    constexpr int kPrecision = std::numeric_limits<FloatType>::digits;      // = p (includes the hidden bit)
    constexpr int kBias = std::numeric_limits<FloatType>::max_exponent - 1 + (kPrecision - 1);
    constexpr int kMinExp = 1 - kBias;
    constexpr uint64_t kHiddenBit = uint64_t { 1 } << (kPrecision - 1); // = 2^(p-1)

    using bits_type = typename std::conditional<kPrecision == 24, uint32_t, uint64_t>::type;

    const uint64_t bits = reinterpret_bits<bits_type>(value);
    const uint64_t E = bits >> (kPrecision - 1);
    const uint64_t F = bits & (kHiddenBit - 1);

    const bool is_denormal = (E == 0);
    const diyfp v = is_denormal
        ? diyfp(F, kMinExp)
        : diyfp(F + kHiddenBit, static_cast<int>(E) - kBias);

    // Compute the boundaries m- and m+ of the floating-point value
    // v = f * 2^e.
    //
    // Determine v- and v+, the floating-point predecessor and successor if v,
    // respectively.
    //
    //      v- = v - 2^e        if f != 2^(p-1) or e == e_min                (A)
    //         = v - 2^(e-1)    if f == 2^(p-1) and e > e_min                (B)
    //
    //      v+ = v + 2^e
    //
    // Let m- = (v- + v) / 2 and m+ = (v + v+) / 2. All real numbers _strictly_
    // between m- and m+ round to v, regardless of how the input rounding
    // algorithm breaks ties.
    //
    //      ---+-------------+-------------+-------------+-------------+---  (A)
    //         v-            m-            v             m+            v+
    //
    //      -----------------+------+------+-------------+-------------+---  (B)
    //                       v-     m-     v             m+            v+

    const bool lower_boundary_is_closer = (F == 0 and E > 1);
    const diyfp m_plus = diyfp(2 * v.f + 1, v.e - 1);
    const diyfp m_minus = lower_boundary_is_closer
        ? diyfp(4 * v.f - 1, v.e - 2)                    // (B)
        : diyfp(2 * v.f - 1, v.e - 1);                   // (A)

    // Determine the normalized w+ = m+.
    const diyfp w_plus = diyfp::normalize(m_plus);

    // Determine w- = m- such that e_(w-) = e_(w+).
    const diyfp w_minus = diyfp::normalize_to(m_minus, w_plus.e);

    return { diyfp::normalize(v), w_minus, w_plus };
}

// Given normalized diyfp w, Grisu needs to find a (normalized) cached
// power-of-ten c, such that the exponent of the product c * w = f * 2^e lies
// within a certain range [alpha, gamma] (Definition 3.2 from [1])
//
//      alpha <= e = e_c + e_w + q <= gamma
//
// or
//
//      f_c * f_w * 2^alpha <= f_c 2^(e_c) * f_w 2^(e_w) * 2^q
//                          <= f_c * f_w * 2^gamma
//
// Since c and w are normalized, i.e. 2^(q-1) <= f < 2^q, this implies
//
//      2^(q-1) * 2^(q-1) * 2^alpha <= c * w * 2^q < 2^q * 2^q * 2^gamma
//
// or
//
//      2^(q - 2 + alpha) <= c * w < 2^(q + gamma)
//
// The choice of (alpha,gamma) determines the size of the table and the form of
// the digit generation procedure. Using (alpha,gamma)=(-60,-32) works out well
// in practice:
//
// The idea is to cut the number c * w = f * 2^e into two parts, which can be
// processed independently: An integral part p1, and a fractional part p2:
//
//      f * 2^e = ( (f div 2^-e) * 2^-e + (f mod 2^-e) ) * 2^e
//              = (f div 2^-e) + (f mod 2^-e) * 2^e
//              = p1 + p2 * 2^e
//
// The conversion of p1 into decimal form requires a series of divisions and
// modulos by (a power of) 10. These operations are faster for 32-bit than for
// 64-bit integers, so p1 should ideally fit into a 32-bit integer. This can be
// achieved by choosing
//
//      -e >= 32   or   e <= -32 := gamma
//
// In order to convert the fractional part
//
//      p2 * 2^e = p2 / 2^-e = d[-1] / 10^1 + d[-2] / 10^2 + ...
//
// into decimal form, the fraction is repeatedly multiplied by 10 and the digits
// d[-i] are extracted in order:
//
//      (10 * p2) div 2^-e = d[-1]
//      (10 * p2) mod 2^-e = d[-2] / 10^1 + ...
//
// The multiplication by 10 must not overflow. It is sufficient to choose
//
//      10 * p2 < 16 * p2 = 2^4 * p2 <= 2^64.
//
// Since p2 = f mod 2^-e < 2^-e,
//
//      -e <= 60   or   e >= -60 := alpha

constexpr int kAlpha = -60;
constexpr int kGamma = -32;

struct cached_power // c = f * 2^e ~= 10^k
{
    uint64_t f;
    int e;
    int k;
};

inline cached_power get_cached_power_for_binary_exponent(int e)
{
    // Now
    //
    //      alpha <= e_c + e + q <= gamma                                    (1)
    //      ==> f_c * 2^alpha <= c * 2^e * 2^q
    //
    // and since the c's are normalized, 2^(q-1) <= f_c,
    //
    //      ==> 2^(q - 1 + alpha) <= c * 2^(e + q)
    //      ==> 2^(alpha - e - 1) <= c
    //
    // If c were an exakt power of ten, i.e. c = 10^k, one may determine k as
    //
    //      k = ceil( log_10( 2^(alpha - e - 1) ) )
    //        = ceil( (alpha - e - 1) * log_10(2) )
    //
    // From the paper:
    // "In theory the result of the procedure could be wrong since c is rounded,
    //  and the computation itself is approximated [...]. In practice, however,
    //  this simple function is sufficient."
    //
    // For IEEE double precision floating-point numbers converted into
    // normalized diyfp's w = f * 2^e, with q = 64,
    //
    //      e >= -1022      (min IEEE exponent)
    //           -52        (p - 1)
    //           -52        (p - 1, possibly normalize denormal IEEE numbers)
    //           -11        (normalize the diyfp)
    //         = -1137
    //
    // and
    //
    //      e <= +1023      (max IEEE exponent)
    //           -52        (p - 1)
    //           -11        (normalize the diyfp)
    //         = 960
    //
    // This binary exponent range [-1137,960] results in a decimal exponent
    // range [-307,324]. One does not need to store a cached power for each
    // k in this range. For each such k it suffices to find a cached power
    // such that the exponent of the product lies in [alpha,gamma].
    // This implies that the difference of the decimal exponents of adjacent
    // table entries must be less than or equal to
    //
    //      floor( (gamma - alpha) * log_10(2) ) = 8.
    //
    // (A smaller distance gamma-alpha would require a larger table.)

    // NB:
    // Actually this function returns c, such that -60 <= e_c + e + 64 <= -34.

    constexpr int kCachedPowersSize = 79;
    constexpr int kCachedPowersMinDecExp = -300;
    constexpr int kCachedPowersDecStep = 8;

    static constexpr cached_power kCachedPowers[] =
    {
        { 0xAB70FE17C79AC6CA, -1060, -300 },
        { 0xFF77B1FCBEBCDC4F, -1034, -292 },
        { 0xBE5691EF416BD60C, -1007, -284 },
        { 0x8DD01FAD907FFC3C, -980, -276 },
        { 0xD3515C2831559A83, -954, -268 },
        { 0x9D71AC8FADA6C9B5, -927, -260 },
        { 0xEA9C227723EE8BCB, -901, -252 },
        { 0xAECC49914078536D, -874, -244 },
        { 0x823C12795DB6CE57, -847, -236 },
        { 0xC21094364DFB5637, -821, -228 },
        { 0x9096EA6F3848984F, -794, -220 },
        { 0xD77485CB25823AC7, -768, -212 },
        { 0xA086CFCD97BF97F4, -741, -204 },
        { 0xEF340A98172AACE5, -715, -196 },
        { 0xB23867FB2A35B28E, -688, -188 },
        { 0x84C8D4DFD2C63F3B, -661, -180 },
        { 0xC5DD44271AD3CDBA, -635, -172 },
        { 0x936B9FCEBB25C996, -608, -164 },
        { 0xDBAC6C247D62A584, -582, -156 },
        { 0xA3AB66580D5FDAF6, -555, -148 },
        { 0xF3E2F893DEC3F126, -529, -140 },
        { 0xB5B5ADA8AAFF80B8, -502, -132 },
        { 0x87625F056C7C4A8B, -475, -124 },
        { 0xC9BCFF6034C13053, -449, -116 },
        { 0x964E858C91BA2655, -422, -108 },
        { 0xDFF9772470297EBD, -396, -100 },
        { 0xA6DFBD9FB8E5B88F, -369, -92 },
        { 0xF8A95FCF88747D94, -343, -84 },
        { 0xB94470938FA89BCF, -316, -76 },
        { 0x8A08F0F8BF0F156B, -289, -68 },
        { 0xCDB02555653131B6, -263, -60 },
        { 0x993FE2C6D07B7FAC, -236, -52 },
        { 0xE45C10C42A2B3B06, -210, -44 },
        { 0xAA242499697392D3, -183, -36 },
        { 0xFD87B5F28300CA0E, -157, -28 },
        { 0xBCE5086492111AEB, -130, -20 },
        { 0x8CBCCC096F5088CC, -103, -12 },
        { 0xD1B71758E219652C, -77, -4 },
        { 0x9C40000000000000, -50, 4 },
        { 0xE8D4A51000000000, -24, 12 },
        { 0xAD78EBC5AC620000, 3, 20 },
        { 0x813F3978F8940984, 30, 28 },
        { 0xC097CE7BC90715B3, 56, 36 },
        { 0x8F7E32CE7BEA5C70, 83, 44 },
        { 0xD5D238A4ABE98068, 109, 52 },
        { 0x9F4F2726179A2245, 136, 60 },
        { 0xED63A231D4C4FB27, 162, 68 },
        { 0xB0DE65388CC8ADA8, 189, 76 },
        { 0x83C7088E1AAB65DB, 216, 84 },
        { 0xC45D1DF942711D9A, 242, 92 },
        { 0x924D692CA61BE758, 269, 100 },
        { 0xDA01EE641A708DEA, 295, 108 },
        { 0xA26DA3999AEF774A, 322, 116 },
        { 0xF209787BB47D6B85, 348, 124 },
        { 0xB454E4A179DD1877, 375, 132 },
        { 0x865B86925B9BC5C2, 402, 140 },
        { 0xC83553C5C8965D3D, 428, 148 },
        { 0x952AB45CFA97A0B3, 455, 156 },
        { 0xDE469FBD99A05FE3, 481, 164 },
        { 0xA59BC234DB398C25, 508, 172 },
        { 0xF6C69A72A3989F5C, 534, 180 },
        { 0xB7DCBF5354E9BECE, 561, 188 },
        { 0x88FCF317F22241E2, 588, 196 },
        { 0xCC20CE9BD35C78A5, 614, 204 },
        { 0x98165AF37B2153DF, 641, 212 },
        { 0xE2A0B5DC971F303A, 667, 220 },
        { 0xA8D9D1535CE3B396, 694, 228 },
        { 0xFB9B7CD9A4A7443C, 720, 236 },
        { 0xBB764C4CA7A44410, 747, 244 },
        { 0x8BAB8EEFB6409C1A, 774, 252 },
        { 0xD01FEF10A657842C, 800, 260 },
        { 0x9B10A4E5E9913129, 827, 268 },
        { 0xE7109BFBA19C0C9D, 853, 276 },
        { 0xAC2820D9623BF429, 880, 284 },
        { 0x80444B5E7AA7CF85, 907, 292 },
        { 0xBF21E44003ACDD2D, 933, 300 },
        { 0x8E679C2F5E44FF8F, 960, 308 },
        { 0xD433179D9C8CB841, 986, 316 },
        { 0x9E19DB92B4E31BA9, 1013, 324 },
    };

    // This computation gives exactly the same results for k as
    //      k = ceil((kAlpha - e - 1) * 0.30102999566398114)
    // for |e| <= 1500, but doesn't require floating-point operations.
    // NB: log_10(2) ~= 78913 / 2^18
    assert(e >= -1500);
    assert(e <= 1500);
    const int f = kAlpha - e - 1;
    const int k = (f * 78913) / (1 << 18) + (f > 0);

    const int index = (-kCachedPowersMinDecExp + k + (kCachedPowersDecStep - 1)) / kCachedPowersDecStep;
    assert(index >= 0);
    assert(index < kCachedPowersSize);
    static_cast<void>(kCachedPowersSize); // Fix warning.

    const cached_power cached = kCachedPowers[index];
    assert(kAlpha <= cached.e + e + 64);
    assert(kGamma >= cached.e + e + 64);

    return cached;
}

inline int find_largest_pow10(const uint32_t n, uint32_t &pow10)
{
    // LCOV_EXCL_START
    if (n >= 1000000000) {
        pow10 = 1000000000;
        return 10;
    }
    // LCOV_EXCL_STOP
    else if (n >= 100000000) {
        pow10 = 100000000;
        return 9;
    } else if (n >= 10000000) {
        pow10 = 10000000;
        return 8;
    } else if (n >= 1000000) {
        pow10 = 1000000;
        return 7;
    } else if (n >= 100000) {
        pow10 = 100000;
        return 6;
    } else if (n >= 10000) {
        pow10 = 10000;
        return 5;
    } else if (n >= 1000) {
        pow10 = 1000;
        return 4;
    } else if (n >= 100) {
        pow10 = 100;
        return 3;
    } else if (n >= 10) {
        pow10 = 10;
        return 2;
    } else {
        pow10 = 1;
        return 1;
    }
}

inline void grisu2_round(char *buf, int len, uint64_t dist, uint64_t delta,
                         uint64_t rest, uint64_t ten_k)
{
    assert(len >= 1);
    assert(dist <= delta);
    assert(rest <= delta);
    assert(ten_k > 0);

    //               <--------------------------- delta ---->
    //                                  <---- dist --------->
    // --------------[------------------+-------------------]--------------
    //               M-                 w                   M+
    //
    //                                  ten_k
    //                                <------>
    //                                       <---- rest ---->
    // --------------[------------------+----+--------------]--------------
    //                                  w    V
    //                                       = buf * 10^k
    //
    // ten_k represents a unit-in-the-last-place in the decimal representation
    // stored in buf.
    // Decrement buf by ten_k while this takes buf closer to w.

    // The tests are written in this order to avoid overflow in unsigned
    // integer arithmetic.

    while (rest < dist
           and delta - rest >= ten_k
           and (rest + ten_k<dist or dist - rest> rest + ten_k - dist)) {
        assert(buf[len - 1] != '0');
        buf[len - 1]--;
        rest += ten_k;
    }
}

inline void grisu2_digit_gen(char *buffer, int &length, int &decimal_exponent,
                             diyfp M_minus, diyfp w, diyfp M_plus)
{
    static_assert(kAlpha >= -60, "internal error");
    static_assert(kGamma <= -32, "internal error");

    // Generates the digits (and the exponent) of a decimal floating-point
    // number V = buffer * 10^decimal_exponent in the range [M-, M+]. The diyfp's
    // w, M- and M+ share the same exponent e, which satisfies alpha <= e <= gamma.
    //
    //               <--------------------------- delta ---->
    //                                  <---- dist --------->
    // --------------[------------------+-------------------]--------------
    //               M-                 w                   M+
    //
    // Grisu2 generates the digits of M+ from left to right and stops as soon as
    // V is in [M-,M+].

    assert(M_plus.e >= kAlpha);
    assert(M_plus.e <= kGamma);

    uint64_t delta = diyfp::sub(M_plus, M_minus).f; // (significand of (M+ - M-), implicit exponent is e)
    uint64_t dist = diyfp::sub(M_plus, w).f;        // (significand of (M+ - w ), implicit exponent is e)

    // Split M+ = f * 2^e into two parts p1 and p2 (note: e < 0):
    //
    //      M+ = f * 2^e
    //         = ((f div 2^-e) * 2^-e + (f mod 2^-e)) * 2^e
    //         = ((p1        ) * 2^-e + (p2        )) * 2^e
    //         = p1 + p2 * 2^e

    const diyfp one(uint64_t { 1 } << -M_plus.e, M_plus.e);

    uint32_t p1 = static_cast<uint32_t>(M_plus.f >> -one.e); // p1 = f div 2^-e (Since -e >= 32, p1 fits into a 32-bit int.)
    uint64_t p2 = M_plus.f & (one.f - 1);                    // p2 = f mod 2^-e

    // 1)
    //
    // Generate the digits of the integral part p1 = d[n-1]...d[1]d[0]

    assert(p1 > 0);

    uint32_t pow10;
    const int k = find_largest_pow10(p1, pow10);

    //      10^(k-1) <= p1 < 10^k, pow10 = 10^(k-1)
    //
    //      p1 = (p1 div 10^(k-1)) * 10^(k-1) + (p1 mod 10^(k-1))
    //         = (d[k-1]         ) * 10^(k-1) + (p1 mod 10^(k-1))
    //
    //      M+ = p1                                             + p2 * 2^e
    //         = d[k-1] * 10^(k-1) + (p1 mod 10^(k-1))          + p2 * 2^e
    //         = d[k-1] * 10^(k-1) + ((p1 mod 10^(k-1)) * 2^-e + p2) * 2^e
    //         = d[k-1] * 10^(k-1) + (                         rest) * 2^e
    //
    // Now generate the digits d[n] of p1 from left to right (n = k-1,...,0)
    //
    //      p1 = d[k-1]...d[n] * 10^n + d[n-1]...d[0]
    //
    // but stop as soon as
    //
    //      rest * 2^e = (d[n-1]...d[0] * 2^-e + p2) * 2^e <= delta * 2^e

    int n = k;
    while (n > 0) {
        // Invariants:
        //      M+ = buffer * 10^n + (p1 + p2 * 2^e)    (buffer = 0 for n = k)
        //      pow10 = 10^(n-1) <= p1 < 10^n
        //
        const uint32_t d = p1 / pow10;  // d = p1 div 10^(n-1)
        const uint32_t r = p1 % pow10;  // r = p1 mod 10^(n-1)
        //
        //      M+ = buffer * 10^n + (d * 10^(n-1) + r) + p2 * 2^e
        //         = (buffer * 10 + d) * 10^(n-1) + (r + p2 * 2^e)
        //
        assert(d <= 9);
        buffer[length++] = static_cast<char>('0' + d); // buffer := buffer * 10 + d
        //
        //      M+ = buffer * 10^(n-1) + (r + p2 * 2^e)
        //
        p1 = r;
        n--;
        //
        //      M+ = buffer * 10^n + (p1 + p2 * 2^e)
        //      pow10 = 10^n
        //

        // Now check if enough digits have been generated.
        // Compute
        //
        //      p1 + p2 * 2^e = (p1 * 2^-e + p2) * 2^e = rest * 2^e
        //
        // Note:
        // Since rest and delta share the same exponent e, it suffices to
        // compare the significands.
        const uint64_t rest = (uint64_t { p1 } << -one.e) + p2;
        if (rest <= delta) {
            // V = buffer * 10^n, with M- <= V <= M+.

            decimal_exponent += n;

            // We may now just stop. But instead look if the buffer could be
            // decremented to bring V closer to w.
            //
            // pow10 = 10^n is now 1 ulp in the decimal representation V.
            // The rounding procedure works with diyfp's with an implicit
            // exponent of e.
            //
            //      10^n = (10^n * 2^-e) * 2^e = ulp * 2^e
            //
            const uint64_t ten_n = uint64_t { pow10 } << -one.e;
            grisu2_round(buffer, length, dist, delta, rest, ten_n);

            return;
        }

        pow10 /= 10;
        //
        //      pow10 = 10^(n-1) <= p1 < 10^n
        // Invariants restored.
    }

    // 2)
    //
    // The digits of the integral part have been generated:
    //
    //      M+ = d[k-1]...d[1]d[0] + p2 * 2^e
    //         = buffer            + p2 * 2^e
    //
    // Now generate the digits of the fractional part p2 * 2^e.
    //
    // Note:
    // No decimal point is generated: the exponent is adjusted instead.
    //
    // p2 actually represents the fraction
    //
    //      p2 * 2^e
    //          = p2 / 2^-e
    //          = d[-1] / 10^1 + d[-2] / 10^2 + ...
    //
    // Now generate the digits d[-m] of p1 from left to right (m = 1,2,...)
    //
    //      p2 * 2^e = d[-1]d[-2]...d[-m] * 10^-m
    //                      + 10^-m * (d[-m-1] / 10^1 + d[-m-2] / 10^2 + ...)
    //
    // using
    //
    //      10^m * p2 = ((10^m * p2) div 2^-e) * 2^-e + ((10^m * p2) mod 2^-e)
    //                = (                   d) * 2^-e + (                   r)
    //
    // or
    //      10^m * p2 * 2^e = d + r * 2^e
    //
    // i.e.
    //
    //      M+ = buffer + p2 * 2^e
    //         = buffer + 10^-m * (d + r * 2^e)
    //         = (buffer * 10^m + d) * 10^-m + 10^-m * r * 2^e
    //
    // and stop as soon as 10^-m * r * 2^e <= delta * 2^e

    assert(p2 > delta);

    int m = 0;
    for (;;) {
        // Invariant:
        //      M+ = buffer * 10^-m + 10^-m * (d[-m-1] / 10 + d[-m-2] / 10^2 + ...) * 2^e
        //         = buffer * 10^-m + 10^-m * (p2                                 ) * 2^e
        //         = buffer * 10^-m + 10^-m * (1/10 * (10 * p2)                   ) * 2^e
        //         = buffer * 10^-m + 10^-m * (1/10 * ((10*p2 div 2^-e) * 2^-e + (10*p2 mod 2^-e)) * 2^e
        //
        assert(p2 <= UINT64_MAX / 10);
        p2 *= 10;
        const uint64_t d = p2 >> -one.e;     // d = (10 * p2) div 2^-e
        const uint64_t r = p2 & (one.f - 1); // r = (10 * p2) mod 2^-e
        //
        //      M+ = buffer * 10^-m + 10^-m * (1/10 * (d * 2^-e + r) * 2^e
        //         = buffer * 10^-m + 10^-m * (1/10 * (d + r * 2^e))
        //         = (buffer * 10 + d) * 10^(-m-1) + 10^(-m-1) * r * 2^e
        //
        assert(d <= 9);
        buffer[length++] = static_cast<char>('0' + d); // buffer := buffer * 10 + d
        //
        //      M+ = buffer * 10^(-m-1) + 10^(-m-1) * r * 2^e
        //
        p2 = r;
        m++;
        //
        //      M+ = buffer * 10^-m + 10^-m * p2 * 2^e
        // Invariant restored.

        // Check if enough digits have been generated.
        //
        //      10^-m * p2 * 2^e <= delta * 2^e
        //              p2 * 2^e <= 10^m * delta * 2^e
        //                    p2 <= 10^m * delta
        delta *= 10;
        dist *= 10;
        if (p2 <= delta) {
            break;
        }
    }

    // V = buffer * 10^-m, with M- <= V <= M+.

    decimal_exponent -= m;

    // 1 ulp in the decimal representation is now 10^-m.
    // Since delta and dist are now scaled by 10^m, we need to do the
    // same with ulp in order to keep the units in sync.
    //
    //      10^m * 10^-m = 1 = 2^-e * 2^e = ten_m * 2^e
    //
    const uint64_t ten_m = one.f;
    grisu2_round(buffer, length, dist, delta, p2, ten_m);

    // By construction this algorithm generates the shortest possible decimal
    // number (Loitsch, Theorem 6.2) which rounds back to w.
    // For an input number of precision p, at least
    //
    //      N = 1 + ceil(p * log_10(2))
    //
    // decimal digits are sufficient to identify all binary floating-point
    // numbers (Matula, "In-and-Out conversions").
    // This implies that the algorithm does not produce more than N decimal
    // digits.
    //
    //      N = 17 for p = 53 (IEEE double precision)
    //      N = 9  for p = 24 (IEEE single precision)
}

inline void grisu2(char *buf, int &len, int &decimal_exponent,
                   diyfp m_minus, diyfp v, diyfp m_plus)
{
    assert(m_plus.e == m_minus.e);
    assert(m_plus.e == v.e);

    //  --------(-----------------------+-----------------------)--------    (A)
    //          m-                      v                       m+
    //
    //  --------------------(-----------+-----------------------)--------    (B)
    //                      m-          v                       m+
    //
    // First scale v (and m- and m+) such that the exponent is in the range
    // [alpha, gamma].

    const cached_power cached = get_cached_power_for_binary_exponent(m_plus.e);

    const diyfp c_minus_k(cached.f, cached.e); // = c ~= 10^-k

    // The exponent of the products is = v.e + c_minus_k.e + q and is in the range [alpha,gamma]
    const diyfp w = diyfp::mul(v, c_minus_k);
    const diyfp w_minus = diyfp::mul(m_minus, c_minus_k);
    const diyfp w_plus = diyfp::mul(m_plus, c_minus_k);

    //  ----(---+---)---------------(---+---)---------------(---+---)----
    //          w-                      w                       w+
    //          = c*m-                  = c*v                   = c*m+
    //
    // diyfp::mul rounds its result and c_minus_k is approximated too. w, w- and
    // w+ are now off by a small amount.
    // In fact:
    //
    //      w - v * 10^k < 1 ulp
    //
    // To account for this inaccuracy, add resp. subtract 1 ulp.
    //
    //  --------+---[---------------(---+---)---------------]---+--------
    //          w-  M-                  w                   M+  w+
    //
    // Now any number in [M-, M+] (bounds included) will round to w when input,
    // regardless of how the input rounding algorithm breaks ties.
    //
    // And digit_gen generates the shortest possible such number in [M-, M+].
    // Note that this does not mean that Grisu2 always generates the shortest
    // possible number in the interval (m-, m+).
    const diyfp M_minus(w_minus.f + 1, w_minus.e);
    const diyfp M_plus(w_plus.f - 1, w_plus.e);

    decimal_exponent = -cached.k; // = -(-k) = k

    grisu2_digit_gen(buf, len, decimal_exponent, M_minus, w, M_plus);
}

template<typename FloatType>
void grisu2(char *buf, int &len, int &decimal_exponent, FloatType value)
{
    static_assert(diyfp::kPrecision >= std::numeric_limits<FloatType>::digits + 3,
                  "internal error: not enough precision");

    assert(std::isfinite(value));
    assert(value > 0);

    // If the neighbors (and boundaries) of 'value' are always computed for double-precision
    // numbers, all float's can be recovered using strtod (and strtof). However, the resulting
    // decimal representations are not exactly "short".
    //
    // The documentation for 'std::to_chars' (http://en.cppreference.com/w/cpp/utility/to_chars)
    // says "value is converted to a string as if by std::sprintf in the default ("C") locale"
    // and since sprintf promotes float's to double's, I think this is exactly what 'std::to_chars'
    // does.
    // On the other hand, the documentation for 'std::to_chars' requires that "parsing the
    // representation using the corresponding std::from_chars function recovers value exactly". That
    // indicates that single precision floating-point numbers should be recovered using
    // 'std::strtof'.
    //
    // NB: If the neighbors are computed for single-precision numbers, there is a single float
    //     (7.0385307e-26f) which can't be recovered using strtod. The resulting double precision
    //     value is off by 1 ulp.
#if 0
    const boundaries w = compute_boundaries(static_cast<double>(value));
#else
    const boundaries w = compute_boundaries(value);
#endif

    grisu2(buf, len, decimal_exponent, w.minus, w.w, w.plus);
}

inline char *append_exponent(char *buf, int e)
{
    assert(e > -1000);
    assert(e < 1000);

    if (e < 0) {
        e = -e;
        *buf++ = '-';
    } else {
        *buf++ = '+';
    }

    uint32_t k = static_cast<uint32_t>(e);
    if (k < 10) {
        // Always print at least two digits in the exponent.
        // This is for compatibility with printf("%g").
        *buf++ = '0';
        *buf++ = static_cast<char>('0' + k);
    } else if (k < 100) {
        *buf++ = static_cast<char>('0' + k / 10);
        k %= 10;
        *buf++ = static_cast<char>('0' + k);
    } else {
        *buf++ = static_cast<char>('0' + k / 100);
        k %= 100;
        *buf++ = static_cast<char>('0' + k / 10);
        k %= 10;
        *buf++ = static_cast<char>('0' + k);
    }

    return buf;
}

inline char *format_buffer(char *buf, int len, int decimal_exponent,
                           int min_exp, int max_exp)
{
    assert(min_exp < 0);
    assert(max_exp > 0);

    const int k = len;
    const int n = len + decimal_exponent;

    // v = buf * 10^(n-k)
    // k is the length of the buffer (number of decimal digits)
    // n is the position of the decimal point relative to the start of the buffer.

    if (k <= n and n <= max_exp) {
        // digits[000]
        // len <= max_exp + 2

        std::memset(buf + k, '0', static_cast<size_t>(n - k));
        // Make it look like a floating-point number (#362, #378)
        buf[n + 0] = '.';
        buf[n + 1] = '0';
        return buf + (n + 2);
    }

    if (0 < n and n <= max_exp) {
        // dig.its
        // len <= max_digits10 + 1

        assert(k > n);

        std::memmove(buf + (n + 1), buf + n, static_cast<size_t>(k - n));
        buf[n] = '.';
        return buf + (k + 1);
    }

    if (min_exp < n and n <= 0) {
        // 0.[000]digits
        // len <= 2 + (-min_exp - 1) + max_digits10

        std::memmove(buf + (2 + -n), buf, static_cast<size_t>(k));
        buf[0] = '0';
        buf[1] = '.';
        std::memset(buf + 2, '0', static_cast<size_t>(-n));
        return buf + (2 + (-n) + k);
    }

    if (k == 1) {
        // dE+123
        // len <= 1 + 5

        buf += 1;
    } else {
        // d.igitsE+123
        // len <= max_digits10 + 1 + 5

        std::memmove(buf + 2, buf + 1, static_cast<size_t>(k - 1));
        buf[1] = '.';
        buf += 1 + k;
    }

    *buf++ = 'e';
    return append_exponent(buf, n - 1);
}

} // namespace dtoa_impl

template<typename FloatType>
char *to_chars(char *first, char *last, FloatType value)
{
    static_cast<void>(last); // maybe unused - fix warning
    assert(std::isfinite(value));

    // Use signbit(value) instead of (value < 0) since signbit works for -0.
    if (std::signbit(value)) {
        value = -value;
        *first++ = '-';
    }

    if (value == 0) { // +-0
        *first++ = '0';
        // Make it look like a floating-point number (#362, #378)
        *first++ = '.';
        *first++ = '0';
        return first;
    }

    assert(last - first >= std::numeric_limits<FloatType>::max_digits10);

    // Compute v = buffer * 10^decimal_exponent.
    // The decimal digits are stored in the buffer, which needs to be interpreted
    // as an unsigned decimal integer.
    // len is the length of the buffer, i.e. the number of decimal digits.
    int len = 0;
    int decimal_exponent = 0;
    dtoa_impl::grisu2(first, len, decimal_exponent, value);

    assert(len <= std::numeric_limits<FloatType>::max_digits10);

    // Format the buffer like printf("%.*g", prec, value)
    constexpr int kMinExp = -4;
    // Use digits10 here to increase compatibility with version 2.
    constexpr int kMaxExp = std::numeric_limits<FloatType>::digits10;

    assert(last - first >= kMaxExp + 2);
    assert(last - first >= 2 + (-kMinExp - 1) + std::numeric_limits<FloatType>::max_digits10);
    assert(last - first >= std::numeric_limits<FloatType>::max_digits10 + 6);

    return dtoa_impl::format_buffer(first, len, decimal_exponent, kMinExp, kMaxExp);
}

} // namespace detail
} // namespace nlohmann

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

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

// #include <nlohmann/detail/output/output_adapters.hpp>

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


namespace nlohmann
{
namespace detail
{
// serialization //

template<typename BasicJsonType>

class serializer
{
    using string_t = typename BasicJsonType::string_t;
    using number_float_t = typename BasicJsonType::number_float_t;
    using number_integer_t = typename BasicJsonType::number_integer_t;
    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
    static constexpr uint8_t UTF8_ACCEPT = 0;
    static constexpr uint8_t UTF8_REJECT = 1;

public:
    serializer(output_adapter_t<char> s, const char ichar)
        : o(std::move(s)), loc(std::localeconv()),
        thousands_sep(loc->thousands_sep == nullptr ? '\0' : *(loc->thousands_sep)), decimal_point(
            loc->decimal_point == nullptr ? '\0' : *(loc->decimal_point)), indent_char(ichar), indent_string(
            512, indent_char)
    {}

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

    void dump(const BasicJsonType &val, const bool pretty_print,
              const bool ensure_ascii,
              const unsigned int indent_step,
              const unsigned int current_indent = 0)
    {
        switch (val.m_type) {
        case value_t::object:
        {
            if (val.m_value.object->empty()) {
                o->write_characters("{}", 2);
                return;
            }

            if (pretty_print) {
                o->write_characters("{\n", 2);

                // variable to hold indentation for recursive calls
                const auto new_indent = current_indent + indent_step;
                if (JSON_UNLIKELY(indent_string.size() < new_indent)) {
                    indent_string.resize(indent_string.size() * 2, ' ');
                }

                // first n-1 elements
                auto i = val.m_value.object->cbegin();
                for (std::size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i) {
                    o->write_characters(indent_string.c_str(), new_indent);
                    o->write_character('\"');
                    dump_escaped(i->first, ensure_ascii);
                    o->write_characters("\": ", 3);
                    dump(i->second, true, ensure_ascii, indent_step, new_indent);
                    o->write_characters(",\n", 2);
                }

                // last element
                assert(i != val.m_value.object->cend());
                assert(std::next(i) == val.m_value.object->cend());
                o->write_characters(indent_string.c_str(), new_indent);
                o->write_character('\"');
                dump_escaped(i->first, ensure_ascii);
                o->write_characters("\": ", 3);
                dump(i->second, true, ensure_ascii, indent_step, new_indent);

                o->write_character('\n');
                o->write_characters(indent_string.c_str(), current_indent);
                o->write_character('}');
            } else {
                o->write_character('{');

                // first n-1 elements
                auto i = val.m_value.object->cbegin();
                for (std::size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i) {
                    o->write_character('\"');
                    dump_escaped(i->first, ensure_ascii);
                    o->write_characters("\":", 2);
                    dump(i->second, false, ensure_ascii, indent_step, current_indent);
                    o->write_character(',');
                }

                // last element
                assert(i != val.m_value.object->cend());
                assert(std::next(i) == val.m_value.object->cend());
                o->write_character('\"');
                dump_escaped(i->first, ensure_ascii);
                o->write_characters("\":", 2);
                dump(i->second, false, ensure_ascii, indent_step, current_indent);

                o->write_character('}');
            }

            return;
        }

        case value_t::array:
        {
            if (val.m_value.array->empty()) {
                o->write_characters("[]", 2);
                return;
            }

            if (pretty_print) {
                o->write_characters("[\n", 2);

                // variable to hold indentation for recursive calls
                const auto new_indent = current_indent + indent_step;
                if (JSON_UNLIKELY(indent_string.size() < new_indent)) {
                    indent_string.resize(indent_string.size() * 2, ' ');
                }

                // first n-1 elements
                for (auto i = val.m_value.array->cbegin();
                     i != val.m_value.array->cend() - 1; ++i) {
                    o->write_characters(indent_string.c_str(), new_indent);
                    dump(*i, true, ensure_ascii, indent_step, new_indent);
                    o->write_characters(",\n", 2);
                }

                // last element
                assert(not val.m_value.array->empty());
                o->write_characters(indent_string.c_str(), new_indent);
                dump(val.m_value.array->back(), true, ensure_ascii, indent_step, new_indent);

                o->write_character('\n');
                o->write_characters(indent_string.c_str(), current_indent);
                o->write_character(']');
            } else {
                o->write_character('[');

                // first n-1 elements
                for (auto i = val.m_value.array->cbegin();
                     i != val.m_value.array->cend() - 1; ++i) {
                    dump(*i, false, ensure_ascii, indent_step, current_indent);
                    o->write_character(',');
                }

                // last element
                assert(not val.m_value.array->empty());
                dump(val.m_value.array->back(), false, ensure_ascii, indent_step, current_indent);

                o->write_character(']');
            }

            return;
        }

        case value_t::string:
        {
            o->write_character('\"');
            dump_escaped(*val.m_value.string, ensure_ascii);
            o->write_character('\"');
            return;
        }

        case value_t::boolean:
        {
            if (val.m_value.boolean) {
                o->write_characters("true", 4);
            } else {
                o->write_characters("false", 5);
            }

            return;
        }

        case value_t::number_integer:
        {
            dump_integer(val.m_value.number_integer);
            return;
        }

        case value_t::number_unsigned:
        {
            dump_integer(val.m_value.number_unsigned);
            return;
        }

        case value_t::number_float:
        {
            dump_float(val.m_value.number_float);
            return;
        }

        case value_t::discarded:
        {
            o->write_characters("<discarded>", 11);
            return;
        }

        case value_t::null:
        {
            o->write_characters("null", 4);
            return;
        }
        }
    }

private:
    void dump_escaped(const string_t &s, const bool ensure_ascii)
    {
        uint32_t codepoint;
        uint8_t state = UTF8_ACCEPT;
        std::size_t bytes = 0;  // number of bytes written to string_buffer

        for (std::size_t i = 0; i < s.size(); ++i) {
            const auto byte = static_cast<uint8_t>(s[i]);

            switch (decode(state, codepoint, byte)) {
            case UTF8_ACCEPT:      // decode found a new code point
            {
                switch (codepoint) {
                case 0x08:         // backspace
                {
                    string_buffer[bytes++] = '\\';
                    string_buffer[bytes++] = 'b';
                    break;
                }

                case 0x09:         // horizontal tab
                {
                    string_buffer[bytes++] = '\\';
                    string_buffer[bytes++] = 't';
                    break;
                }

                case 0x0A:         // newline
                {
                    string_buffer[bytes++] = '\\';
                    string_buffer[bytes++] = 'n';
                    break;
                }

                case 0x0C:         // formfeed
                {
                    string_buffer[bytes++] = '\\';
                    string_buffer[bytes++] = 'f';
                    break;
                }

                case 0x0D:         // carriage return
                {
                    string_buffer[bytes++] = '\\';
                    string_buffer[bytes++] = 'r';
                    break;
                }

                case 0x22:         // quotation mark
                {
                    string_buffer[bytes++] = '\\';
                    string_buffer[bytes++] = '\"';
                    break;
                }

                case 0x5C:         // reverse solidus
                {
                    string_buffer[bytes++] = '\\';
                    string_buffer[bytes++] = '\\';
                    break;
                }

                default:
                {
                    // escape control characters (0x00..0x1F) or, if
                    // ensure_ascii parameter is used, non-ASCII characters
                    if ((codepoint <= 0x1F) or (ensure_ascii and (codepoint >= 0x7F))) {
                        if (codepoint <= 0xFFFF) {
                            std::snprintf(string_buffer.data() + bytes, 7, "\\u%04x",
                                          static_cast<uint16_t>(codepoint));
                            bytes += 6;
                        } else {
                            std::snprintf(string_buffer.data() + bytes, 13, "\\u%04x\\u%04x",
                                          static_cast<uint16_t>(0xD7C0 + (codepoint >> 10)),
                                          static_cast<uint16_t>(0xDC00 + (codepoint & 0x3FF)));
                            bytes += 12;
                        }
                    } else {
                        // copy byte to buffer (all previous bytes
                        // been copied have in default case above)
                        string_buffer[bytes++] = s[i];
                    }

                    break;
                }
                }

                // write buffer and reset index; there must be 13 bytes
                // left, as this is the maximal number of bytes to be
                // written ("\uxxxx\uxxxx\0") for one code point
                if (string_buffer.size() - bytes < 13) {
                    o->write_characters(string_buffer.data(), bytes);
                    bytes = 0;
                }

                break;
            }

            case UTF8_REJECT:      // decode found invalid UTF-8 byte
            {
                std::stringstream ss;
                ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex <<
                    static_cast<int>(byte);
                JSON_THROW(type_error::create(316,
                                              "invalid UTF-8 byte at index " + std::to_string(i) + ": 0x" +
                                              ss.str()));
            }

            default:      // decode found yet incomplete multi-byte code point
            {
                if (not ensure_ascii) {
                    // code point will not be escaped - copy byte to buffer
                    string_buffer[bytes++] = s[i];
                }

                break;
            }
            }
        }

        if (JSON_LIKELY(state == UTF8_ACCEPT)) {
            // write buffer
            if (bytes > 0) {
                o->write_characters(string_buffer.data(), bytes);
            }
        } else {
            // we finish reading, but do not accept: string was incomplete
            std::stringstream ss;
            ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex <<
                static_cast<int>(static_cast<uint8_t>(s.back()));
            JSON_THROW(type_error::create(316, "incomplete UTF-8 string; last byte: 0x" + ss.str()));
        }
    }

    template<typename NumberType, detail::enable_if_t<
                 std::is_same<NumberType, number_unsigned_t>::value or
                 std::is_same<NumberType, number_integer_t>::value,
                 int> = 0>
    void dump_integer(NumberType x)
    {
        // special case for "0"
        if (x == 0) {
            o->write_character('0');
            return;
        }

        const bool is_negative = (x <= 0) and (x != 0);  // see issue #755
        std::size_t i = 0;

        while (x != 0) {
            // spare 1 byte for '\0'
            assert(i < number_buffer.size() - 1);

            const auto digit = std::labs(static_cast<long>(x % 10));
            number_buffer[i++] = static_cast<char>('0' + digit);
            x /= 10;
        }

        if (is_negative) {
            // make sure there is capacity for the '-'
            assert(i < number_buffer.size() - 2);
            number_buffer[i++] = '-';
        }

        std::reverse(number_buffer.begin(), number_buffer.begin() + i);
        o->write_characters(number_buffer.data(), i);
    }

    void dump_float(number_float_t x)
    {
        // NaN / inf
        if (not std::isfinite(x)) {
            o->write_characters("null", 4);
            return;
        }

        // If number_float_t is an IEEE-754 single or double precision number,
        // use the Grisu2 algorithm to produce short numbers which are
        // guaranteed to round-trip, using strtof and strtod, resp.
        //
        // NB: The test below works if <long double> == <double>.
        static constexpr bool is_ieee_single_or_double
            = (std::numeric_limits<number_float_t>::is_iec559 and std::numeric_limits<number_float_t>::digits
               == 24 and std::numeric_limits<number_float_t>::max_exponent == 128) or
                (std::numeric_limits<number_float_t>::is_iec559 and std::numeric_limits<number_float_t>::
                 digits == 53 and std::numeric_limits<number_float_t>::max_exponent == 1024);

        dump_float(x, std::integral_constant<bool, is_ieee_single_or_double>());
    }

    void dump_float(number_float_t x, std::true_type /*is_ieee_single_or_double*/)
    {
        char *begin = number_buffer.data();
        char *end = ::nlohmann::detail::to_chars(begin, begin + number_buffer.size(), x);

        o->write_characters(begin, static_cast<size_t>(end - begin));
    }

    void dump_float(number_float_t x, std::false_type /*is_ieee_single_or_double*/)
    {
        // get number of digits for a float -> text -> float round-trip
        static constexpr auto d = std::numeric_limits<number_float_t>::max_digits10;

        // the actual conversion
        std::ptrdiff_t len = snprintf(number_buffer.data(), number_buffer.size(), "%.*g", d, x);

        // negative value indicates an error
        assert(len > 0);
        // check if buffer was large enough
        assert(static_cast<std::size_t>(len) < number_buffer.size());

        // erase thousands separator
        if (thousands_sep != '\0') {
            const auto end = std::remove(number_buffer.begin(),
                                         number_buffer.begin() + len, thousands_sep);
            std::fill(end, number_buffer.end(), '\0');
            assert((end - number_buffer.begin()) <= len);
            len = (end - number_buffer.begin());
        }

        // convert decimal point to '.'
        if (decimal_point != '\0' and decimal_point != '.') {
            const auto dec_pos = std::find(number_buffer.begin(), number_buffer.end(), decimal_point);
            if (dec_pos != number_buffer.end()) {
                *dec_pos = '.';
            }
        }

        o->write_characters(number_buffer.data(), static_cast<std::size_t>(len));

        // determine if need to append ".0"
        const bool value_is_int_like =
            std::none_of(number_buffer.begin(), number_buffer.begin() + len + 1,
                         [](char c) {
                    return (c == '.' or c == 'e');
                });

        if (value_is_int_like) {
            o->write_characters(".0", 2);
        }
    }

    static uint8_t decode(uint8_t &state, uint32_t &codep, const uint8_t byte) noexcept
    {
        static const std::array<uint8_t, 400> utf8d =
        {
            {
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0,                                                                                              // 00..1F
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0,                                                                                              // 20..3F
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0,                                                                                              // 40..5F
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                0,                                                                                              // 60..7F
                1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
                9,                                                                                              // 80..9F
                7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
                7,                                                                                              // A0..BF
                8, 8, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
                2,                                                                                              // C0..DF
                0xA, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x4, 0x3, 0x3, // E0..EF
                0xB, 0x6, 0x6, 0x6, 0x5, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, // F0..FF
                0x0, 0x1, 0x2, 0x3, 0x5, 0x8, 0x7, 0x1, 0x1, 0x1, 0x4, 0x6, 0x1, 0x1, 0x1, 0x1, // s0..s0
                1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1,
                1,                                                                                              // s1..s2
                1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1,
                1,                                                                                              // s3..s4
                1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1,
                1,                                                                                              // s5..s6
                1, 3, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 // s7..s8
            }
        };

        const uint8_t type = utf8d[byte];

        codep = (state != UTF8_ACCEPT)
            ? (byte & 0x3fu) | (codep << 6)
            : static_cast<uint32_t>(0xff >> type) & (byte);

        state = utf8d[256u + state * 16u + type];
        return state;
    }

private:
    output_adapter_t<char> o = nullptr;

    std::array<char, 64> number_buffer { {} };

    const std::lconv *loc = nullptr;
    const char thousands_sep = '\0';
    const char decimal_point = '\0';

    std::array<char, 512> string_buffer { {} };

    const char indent_char;
    string_t indent_string;
};

} // namespace detail
} // namespace nlohmann

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


#include <initializer_list>
#include <utility>

namespace nlohmann
{
namespace detail
{
template<typename BasicJsonType>

class json_ref
{
public:
    using value_type = BasicJsonType;

    json_ref(value_type &&value)
        : owned_value(std::move(value)), value_ref(&owned_value), is_rvalue(true)
    {}

    json_ref(const value_type &value)
        : value_ref(const_cast<value_type *>(&value)), is_rvalue(false)
    {}

    json_ref(std::initializer_list<json_ref> init)
        : owned_value(init), value_ref(&owned_value), is_rvalue(true)
    {}

    template<class... Args>
    json_ref(Args && ... args)
        : owned_value(std::forward<Args>(args) ...), value_ref(&owned_value), is_rvalue(true)
    {}

    // class should be movable only
    json_ref(json_ref &&) = default;
    json_ref(const json_ref &) = delete;
    json_ref &operator=(const json_ref &) = delete;

    value_type moved_or_copied() const
    {
        if (is_rvalue) {
            return std::move(*value_ref);
        }

        return *value_ref;
    }

    value_type const &operator*() const
    {
        return *static_cast<value_type const *>(value_ref);
    }

    value_type const *operator->() const
    {
        return static_cast<value_type const *>(value_ref);
    }

private:
    mutable value_type owned_value = nullptr;
    value_type *value_ref = nullptr;
    const bool is_rvalue;
};

} // namespace detail
} // namespace nlohmann

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


#include <cassert> // assert
#include <numeric> // accumulate
#include <string> // string
#include <vector> // vector

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

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

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


namespace nlohmann
{
template<typename BasicJsonType>

class json_pointer
{
    // allow basic_json to access private members
    NLOHMANN_BASIC_JSON_TPL_DECLARATION
    friend class basic_json;

public:
    explicit json_pointer(const std::string &s = "")
        : reference_tokens(split(s))
    {}

    std::string to_string() const noexcept
    {
        return std::accumulate(reference_tokens.begin(), reference_tokens.end(),
                               std::string {},
                               [](const std::string &a, const std::string &b) {
                return a + "/" + escape(b);
            });
    }

    operator std::string() const
    {
        return to_string();
    }

    static int array_index(const std::string &s)
    {
        std::size_t processed_chars = 0;
        const int res = std::stoi(s, &processed_chars);

        // check if the string was completely read
        if (JSON_UNLIKELY(processed_chars != s.size())) {
            JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + s + "'"));
        }

        return res;
    }

private:
    std::string pop_back()
    {
        if (JSON_UNLIKELY(is_root())) {
            JSON_THROW(detail::out_of_range::create(405, "JSON pointer has no parent"));
        }

        auto last = reference_tokens.back();
        reference_tokens.pop_back();
        return last;
    }

    bool is_root() const
    {
        return reference_tokens.empty();
    }

    json_pointer top() const
    {
        if (JSON_UNLIKELY(is_root())) {
            JSON_THROW(detail::out_of_range::create(405, "JSON pointer has no parent"));
        }

        json_pointer result = *this;
        result.reference_tokens = { reference_tokens[0] };
        return result;
    }

    BasicJsonType &get_and_create(BasicJsonType &j) const
    {
        using size_type = typename BasicJsonType::size_type;
        auto result = &j;

        // in case no reference tokens exist, return a reference to the JSON value
        // j which will be overwritten by a primitive value
        for (const auto &reference_token : reference_tokens) {
            switch (result->m_type) {
            case detail::value_t::null:
            {
                if (reference_token == "0") {
                    // start a new array if reference token is 0
                    result = &result->operator[](0);
                } else {
                    // start a new object otherwise
                    result = &result->operator[](reference_token);
                }

                break;
            }

            case detail::value_t::object:
            {
                // create an entry in the object
                result = &result->operator[](reference_token);
                break;
            }

            case detail::value_t::array:
            {
                // create an entry in the array
                JSON_TRY
                {
                    result = &result->operator[](static_cast<size_type>(array_index(reference_token)));
                }
                JSON_CATCH(std::invalid_argument &)
                {
                    JSON_THROW(detail::parse_error::create(109, 0,
                                                           "array index '" + reference_token +
                                                           "' is not a number"));
                }
                break;
            }

            /*
            The following code is only reached if there exists a reference
            token _and_ the current value is primitive. In this case, we have
            an error situation, because primitive values may only occur as
            single value; that is, with an empty list of reference tokens.
            */default:
                JSON_THROW(detail::type_error::create(313, "invalid value to unflatten"));
            }
        }

        return *result;
    }

    BasicJsonType &get_unchecked(BasicJsonType *ptr) const
    {
        using size_type = typename BasicJsonType::size_type;
        for (const auto &reference_token : reference_tokens) {
            // convert null values to arrays or objects before continuing
            if (ptr->m_type == detail::value_t::null) {
                // check if reference token is a number
                const bool nums =
                    std::all_of(reference_token.begin(), reference_token.end(),
                                [](const char x) {
                        return (x >= '0' and x <= '9');
                    });

                // change value to array for numbers or "-" or to object otherwise
                *ptr = (nums or reference_token == "-")
                    ? detail::value_t::array
                    : detail::value_t::object;
            }

            switch (ptr->m_type) {
            case detail::value_t::object:
            {
                // use unchecked object access
                ptr = &ptr->operator[](reference_token);
                break;
            }

            case detail::value_t::array:
            {
                // error condition (cf. RFC 6901, Sect. 4)
                if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0')) {
                    JSON_THROW(detail::parse_error::create(106, 0,
                                                           "array index '" + reference_token +
                                                           "' must not begin with '0'"));
                }

                if (reference_token == "-") {
                    // explicitly treat "-" as index beyond the end
                    ptr = &ptr->operator[](ptr->m_value.array->size());
                } else {
                    // convert array index to number; unchecked access
                    JSON_TRY
                    {
                        ptr = &ptr->operator[](
                                static_cast<size_type>(array_index(reference_token)));
                    }
                    JSON_CATCH(std::invalid_argument &)
                    {
                        JSON_THROW(detail::parse_error::create(109, 0,
                                                               "array index '" + reference_token +
                                                               "' is not a number"));
                    }
                }

                break;
            }

            default:
                JSON_THROW(detail::out_of_range::create(404,
                                                        "unresolved reference token '" + reference_token +
                                                        "'"));
            }
        }

        return *ptr;
    }

    BasicJsonType &get_checked(BasicJsonType *ptr) const
    {
        using size_type = typename BasicJsonType::size_type;
        for (const auto &reference_token : reference_tokens) {
            switch (ptr->m_type) {
            case detail::value_t::object:
            {
                // note: at performs range check
                ptr = &ptr->at(reference_token);
                break;
            }

            case detail::value_t::array:
            {
                if (JSON_UNLIKELY(reference_token == "-")) {
                    // "-" always fails the range check
                    JSON_THROW(detail::out_of_range::create(402,
                                                            "array index '-' (" +
                                                            std::to_string(ptr->m_value.array->size()) +
                                                            ") is out of range"));
                }

                // error condition (cf. RFC 6901, Sect. 4)
                if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0')) {
                    JSON_THROW(detail::parse_error::create(106, 0,
                                                           "array index '" + reference_token +
                                                           "' must not begin with '0'"));
                }

                // note: at performs range check
                JSON_TRY
                {
                    ptr = &ptr->at(static_cast<size_type>(array_index(reference_token)));
                }
                JSON_CATCH(std::invalid_argument &)
                {
                    JSON_THROW(detail::parse_error::create(109, 0,
                                                           "array index '" + reference_token +
                                                           "' is not a number"));
                }
                break;
            }

            default:
                JSON_THROW(detail::out_of_range::create(404,
                                                        "unresolved reference token '" + reference_token +
                                                        "'"));
            }
        }

        return *ptr;
    }

    const BasicJsonType &get_unchecked(const BasicJsonType *ptr) const
    {
        using size_type = typename BasicJsonType::size_type;
        for (const auto &reference_token : reference_tokens) {
            switch (ptr->m_type) {
            case detail::value_t::object:
            {
                // use unchecked object access
                ptr = &ptr->operator[](reference_token);
                break;
            }

            case detail::value_t::array:
            {
                if (JSON_UNLIKELY(reference_token == "-")) {
                    // "-" cannot be used for const access
                    JSON_THROW(detail::out_of_range::create(402,
                                                            "array index '-' (" +
                                                            std::to_string(ptr->m_value.array->size()) +
                                                            ") is out of range"));
                }

                // error condition (cf. RFC 6901, Sect. 4)
                if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0')) {
                    JSON_THROW(detail::parse_error::create(106, 0,
                                                           "array index '" + reference_token +
                                                           "' must not begin with '0'"));
                }

                // use unchecked array access
                JSON_TRY
                {
                    ptr = &ptr->operator[](
                            static_cast<size_type>(array_index(reference_token)));
                }
                JSON_CATCH(std::invalid_argument &)
                {
                    JSON_THROW(detail::parse_error::create(109, 0,
                                                           "array index '" + reference_token +
                                                           "' is not a number"));
                }
                break;
            }

            default:
                JSON_THROW(detail::out_of_range::create(404,
                                                        "unresolved reference token '" + reference_token +
                                                        "'"));
            }
        }

        return *ptr;
    }

    const BasicJsonType &get_checked(const BasicJsonType *ptr) const
    {
        using size_type = typename BasicJsonType::size_type;
        for (const auto &reference_token : reference_tokens) {
            switch (ptr->m_type) {
            case detail::value_t::object:
            {
                // note: at performs range check
                ptr = &ptr->at(reference_token);
                break;
            }

            case detail::value_t::array:
            {
                if (JSON_UNLIKELY(reference_token == "-")) {
                    // "-" always fails the range check
                    JSON_THROW(detail::out_of_range::create(402,
                                                            "array index '-' (" +
                                                            std::to_string(ptr->m_value.array->size()) +
                                                            ") is out of range"));
                }

                // error condition (cf. RFC 6901, Sect. 4)
                if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0')) {
                    JSON_THROW(detail::parse_error::create(106, 0,
                                                           "array index '" + reference_token +
                                                           "' must not begin with '0'"));
                }

                // note: at performs range check
                JSON_TRY
                {
                    ptr = &ptr->at(static_cast<size_type>(array_index(reference_token)));
                }
                JSON_CATCH(std::invalid_argument &)
                {
                    JSON_THROW(detail::parse_error::create(109, 0,
                                                           "array index '" + reference_token +
                                                           "' is not a number"));
                }
                break;
            }

            default:
                JSON_THROW(detail::out_of_range::create(404,
                                                        "unresolved reference token '" + reference_token +
                                                        "'"));
            }
        }

        return *ptr;
    }

    static std::vector<std::string> split(const std::string &reference_string)
    {
        std::vector<std::string> result;

        // special case: empty reference string -> no reference tokens
        if (reference_string.empty()) {
            return result;
        }

        // check if nonempty reference string begins with slash
        if (JSON_UNLIKELY(reference_string[0] != '/')) {
            JSON_THROW(detail::parse_error::create(107, 1,
                                                   "JSON pointer must be empty or begin with '/' - was: '" +
                                                   reference_string + "'"));
        }

        // extract the reference tokens:
        // - slash: position of the last read slash (or end of string)
        // - start: position after the previous slash
        for (
            // search for the first slash after the first character
            std::size_t slash = reference_string.find_first_of('/', 1),
            // set the beginning of the first reference token
            start = 1;
            // we can stop if start == string::npos+1 = 0
            start != 0;
            // set the beginning of the next reference token
            // (will eventually be 0 if slash == std::string::npos)
            start = slash + 1,
            // find next slash
            slash = reference_string.find_first_of('/', start)) {
            // use the text between the beginning of the reference token
            // (start) and the last slash (slash).
            auto reference_token = reference_string.substr(start, slash - start);

            // check reference tokens are properly escaped
            for (std::size_t pos = reference_token.find_first_of('~');
                 pos != std::string::npos;
                 pos = reference_token.find_first_of('~', pos + 1)) {
                assert(reference_token[pos] == '~');

                // ~ must be followed by 0 or 1
                if (JSON_UNLIKELY(pos == reference_token.size() - 1 or
                                  (reference_token[pos + 1] != '0' and
                                   reference_token[pos + 1] != '1'))) {
                    JSON_THROW(detail::parse_error::create(108, 0,
                                                           "escape character '~' must be followed with '0' or '1'"));
                }
            }

            // finally, store the reference token
            unescape(reference_token);
            result.push_back(reference_token);
        }

        return result;
    }

    static void replace_substring(std::string &s, const std::string &f,
                                  const std::string &t)
    {
        assert(not f.empty());
        for (auto pos = s.find(f);                // find first occurrence of f
             pos != std::string::npos;            // make sure f was found
             s.replace(pos, f.size(), t),         // replace with t, and
             pos = s.find(f, pos + t.size()))     // find next occurrence of f
        {}
    }

    static std::string escape(std::string s)
    {
        replace_substring(s, "~", "~0");
        replace_substring(s, "/", "~1");
        return s;
    }

    static void unescape(std::string &s)
    {
        replace_substring(s, "~1", "/");
        replace_substring(s, "~0", "~");
    }

    static void flatten(const std::string &reference_string,
                        const BasicJsonType &value,
                        BasicJsonType &result)
    {
        switch (value.m_type) {
        case detail::value_t::array:
        {
            if (value.m_value.array->empty()) {
                // flatten empty array as null
                result[reference_string] = nullptr;
            } else {
                // iterate array and use index as reference string
                for (std::size_t i = 0; i < value.m_value.array->size(); ++i) {
                    flatten(reference_string + "/" + std::to_string(i),
                            value.m_value.array->operator[](i), result);
                }
            }

            break;
        }

        case detail::value_t::object:
        {
            if (value.m_value.object->empty()) {
                // flatten empty object as null
                result[reference_string] = nullptr;
            } else {
                // iterate object and use keys as reference string
                for (const auto &element : *value.m_value.object) {
                    flatten(reference_string + "/" + escape(element.first), element.second, result);
                }
            }

            break;
        }

        default:
        {
            // add primitive value with its reference string
            result[reference_string] = value;
            break;
        }
        }
    }

    static BasicJsonType
    unflatten(const BasicJsonType &value)
    {
        if (JSON_UNLIKELY(not value.is_object())) {
            JSON_THROW(detail::type_error::create(314, "only objects can be unflattened"));
        }

        BasicJsonType result;

        // iterate the JSON object values
        for (const auto &element : *value.m_value.object) {
            if (JSON_UNLIKELY(not element.second.is_primitive())) {
                JSON_THROW(detail::type_error::create(315, "values in object must be primitive"));
            }

            // assign value to reference pointed to by JSON pointer; Note that if
            // the JSON pointer is "" (i.e., points to the whole value), function
            // get_and_create returns a reference to result itself. An assignment
            // will then create a primitive value.
            json_pointer(element.first).get_and_create(result) = element.second;
        }

        return result;
    }

    friend bool operator==(json_pointer const &lhs,
                           json_pointer const &rhs) noexcept
    {
        return (lhs.reference_tokens == rhs.reference_tokens);
    }

    friend bool operator!=(json_pointer const &lhs,
                           json_pointer const &rhs) noexcept
    {
        return not (lhs == rhs);
    }

    std::vector<std::string> reference_tokens;
};

} // namespace nlohmann

// #include <nlohmann/adl_serializer.hpp>


#include <utility>

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

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


namespace nlohmann
{
template<typename, typename>
struct adl_serializer
{
    template<typename BasicJsonType, typename ValueType>
    static void from_json(BasicJsonType &&j, ValueType &val) noexcept (
        noexcept (::nlohmann::from_json(std::forward<BasicJsonType>(j), val)))
    {
        ::nlohmann::from_json(std::forward<BasicJsonType>(j), val);
    }

    template<typename BasicJsonType, typename ValueType>
    static void to_json(BasicJsonType &j, ValueType &&val) noexcept (
        noexcept (::nlohmann::to_json(j, std::forward<ValueType>(val))))
    {
        ::nlohmann::to_json(j, std::forward<ValueType>(val));
    }
};

} // namespace nlohmann


namespace nlohmann
{

NLOHMANN_BASIC_JSON_TPL_DECLARATION

class basic_json
{
private:
    template<detail::value_t> friend struct detail::external_constructor;
    friend ::nlohmann::json_pointer<basic_json>;
    friend ::nlohmann::detail::parser<basic_json>;
    friend ::nlohmann::detail::serializer<basic_json>;
    template<typename BasicJsonType>
    friend class ::nlohmann::detail::iter_impl;
    template<typename BasicJsonType, typename CharType>
    friend class ::nlohmann::detail::binary_writer;
    template<typename BasicJsonType>
    friend class ::nlohmann::detail::binary_reader;

    using basic_json_t = NLOHMANN_BASIC_JSON_TPL;

    // convenience aliases for types residing in namespace detail;
    using lexer = ::nlohmann::detail::lexer<basic_json>;
    using parser = ::nlohmann::detail::parser<basic_json>;

    using primitive_iterator_t = ::nlohmann::detail::primitive_iterator_t;
    template<typename BasicJsonType>
    using internal_iterator = ::nlohmann::detail::internal_iterator<BasicJsonType>;
    template<typename BasicJsonType>
    using iter_impl = ::nlohmann::detail::iter_impl<BasicJsonType>;
    template<typename Iterator>
    using iteration_proxy = ::nlohmann::detail::iteration_proxy<Iterator>;
    template<typename Base> using json_reverse_iterator = ::nlohmann::detail::json_reverse_iterator<Base>;

    template<typename CharType>
    using output_adapter_t = ::nlohmann::detail::output_adapter_t<CharType>;

    using binary_reader = ::nlohmann::detail::binary_reader<basic_json>;
    template<typename CharType> using binary_writer = ::nlohmann::detail::binary_writer<basic_json, CharType>;

    using serializer = ::nlohmann::detail::serializer<basic_json>;

public:
    using value_t = detail::value_t;
    using json_pointer = ::nlohmann::json_pointer<basic_json>;
    template<typename T, typename SFINAE>
    using json_serializer = JSONSerializer<T, SFINAE>;
    using initializer_list_t = std::initializer_list<detail::json_ref<basic_json>>;

    // exceptions //


    using exception = detail::exception;
    using parse_error = detail::parse_error;
    using invalid_iterator = detail::invalid_iterator;
    using type_error = detail::type_error;
    using out_of_range = detail::out_of_range;
    using other_error = detail::other_error;



    // container types //


    using value_type = basic_json;

    using reference = value_type &;
    using const_reference = const value_type &;

    using difference_type = std::ptrdiff_t;
    using size_type = std::size_t;

    using allocator_type = AllocatorType<basic_json>;

    using pointer = typename std::allocator_traits<allocator_type>::pointer;
    using const_pointer = typename std::allocator_traits<allocator_type>::const_pointer;

    using iterator = iter_impl<basic_json>;
    using const_iterator = iter_impl<const basic_json>;
    using reverse_iterator = json_reverse_iterator<typename basic_json::iterator>;
    using const_reverse_iterator = json_reverse_iterator<typename basic_json::const_iterator>;



    static allocator_type get_allocator()
    {
        return allocator_type();
    }

    static basic_json meta()
    {
        basic_json result;

        result["copyright"] = "(C) 2013-2017 Niels Lohmann";
        result["name"] = "JSON for Modern C++";
        result["url"] = "https://github.com/nlohmann/json";
        result["version"]["string"] =
            std::to_string(NLOHMANN_JSON_VERSION_MAJOR) + "." +
            std::to_string(NLOHMANN_JSON_VERSION_MINOR) + "." +
            std::to_string(NLOHMANN_JSON_VERSION_PATCH);
        result["version"]["major"] = NLOHMANN_JSON_VERSION_MAJOR;
        result["version"]["minor"] = NLOHMANN_JSON_VERSION_MINOR;
        result["version"]["patch"] = NLOHMANN_JSON_VERSION_PATCH;

#ifdef _WIN32
        result["platform"] = "win32";
#elif defined __linux__
        result["platform"] = "linux";
#elif defined __APPLE__
        result["platform"] = "apple";
#elif defined __unix__
        result["platform"] = "unix";
#else
        result["platform"] = "unknown";
#endif

#if defined(__ICC) || defined(__INTEL_COMPILER)
        result["compiler"] = { { "family", "icc" }, { "version", __INTEL_COMPILER } };
#elif defined(__clang__)
        result["compiler"] = { { "family", "clang" }, { "version", __clang_version__ } };
#elif defined(__GNUC__) || defined(__GNUG__)
        result["compiler"] =
        { { "family", "gcc" },
          { "version",
            std::to_string(__GNUC__) + "." + std::to_string(__GNUC_MINOR__) + "." + std::to_string(
                __GNUC_PATCHLEVEL__) } };
#elif defined(__HP_cc) || defined(__HP_aCC)
        result["compiler"] = "hp"
#elif defined(__IBMCPP__)
        result["compiler"] = { { "family", "ilecpp" }, { "version", __IBMCPP__ } };
#elif defined(_MSC_VER)
        result["compiler"] = { { "family", "msvc" }, { "version", _MSC_VER } };
#elif defined(__PGI)
        result["compiler"] = { { "family", "pgcpp" }, { "version", __PGI } };
#elif defined(__SUNPRO_CC)
        result["compiler"] = { { "family", "sunpro" }, { "version", __SUNPRO_CC } };
#else
        result["compiler"] = { { "family", "unknown" }, { "version", "unknown" } };
#endif

#ifdef __cplusplus
        result["compiler"]["c++"] = std::to_string(__cplusplus);
#else
        result["compiler"]["c++"] = "unknown";
#endif
        return result;
    }


    // JSON value data types //


#if defined(JSON_HAS_CPP_14)
    // Use transparent comparator if possible, combined with perfect forwarding
    // on find() and count() calls prevents unnecessary string construction.
    using object_comparator_t = std::less<>;
#else
    using object_comparator_t = std::less<StringType>;
#endif

    using object_t = ObjectType<StringType,
                                basic_json,
                                object_comparator_t,
                                AllocatorType<std::pair<const StringType,
                                                        basic_json>>>;

    using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;

    using string_t = StringType;

    using boolean_t = BooleanType;

    using number_integer_t = NumberIntegerType;

    using number_unsigned_t = NumberUnsignedType;

    using number_float_t = NumberFloatType;


private:

    template<typename T, typename... Args>
    static T *create(Args && ... args)
    {
        AllocatorType<T> alloc;
        using AllocatorTraits = std::allocator_traits<AllocatorType<T>>;

        auto deleter = [&](T *object) {
                AllocatorTraits::deallocate(alloc, object, 1);
            };
        std::unique_ptr<T, decltype(deleter)> object(AllocatorTraits::allocate(alloc, 1), deleter);
        AllocatorTraits::construct(alloc, object.get(), std::forward<Args>(args) ...);
        assert(object != nullptr);
        return object.release();
    }

    // JSON value storage //

    union json_value
    {
        object_t *object;
        array_t *array;
        string_t *string;
        boolean_t boolean;
        number_integer_t number_integer;
        number_unsigned_t number_unsigned;
        number_float_t number_float;

        json_value() = default;
        json_value(boolean_t v) noexcept : boolean(v) {}
        json_value(number_integer_t v) noexcept : number_integer(v) {}
        json_value(number_unsigned_t v) noexcept : number_unsigned(v) {}
        json_value(number_float_t v) noexcept : number_float(v) {}
        json_value(value_t t)
        {
            switch (t) {
            case value_t::object:
            {
                object = create<object_t>();
                break;
            }

            case value_t::array:
            {
                array = create<array_t>();
                break;
            }

            case value_t::string:
            {
                string = create<string_t>("");
                break;
            }

            case value_t::boolean:
            {
                boolean = boolean_t(false);
                break;
            }

            case value_t::number_integer:
            {
                number_integer = number_integer_t(0);
                break;
            }

            case value_t::number_unsigned:
            {
                number_unsigned = number_unsigned_t(0);
                break;
            }

            case value_t::number_float:
            {
                number_float = number_float_t(0.0);
                break;
            }

            case value_t::null:
            {
                object = nullptr;      // silence warning, see #821
                break;
            }

            default:
            {
                object = nullptr;      // silence warning, see #821
                if (JSON_UNLIKELY(t == value_t::null)) {
                    JSON_THROW(other_error::create(500, "961c151d2e87f2686a955a9be24d316f1362bf21 3.1.1"));     // LCOV_EXCL_LINE
                }

                break;
            }
            }
        }

        json_value(const string_t &value)
        {
            string = create<string_t>(value);
        }

        json_value(string_t && value)
        {
            string = create<string_t>(std::move(value));
        }

        json_value(const object_t &value)
        {
            object = create<object_t>(value);
        }

        json_value(object_t && value)
        {
            object = create<object_t>(std::move(value));
        }

        json_value(const array_t &value)
        {
            array = create<array_t>(value);
        }

        json_value(array_t && value)
        {
            array = create<array_t>(std::move(value));
        }

        void destroy(value_t t) noexcept
        {
            switch (t) {
            case value_t::object:
            {
                AllocatorType<object_t> alloc;
                std::allocator_traits<decltype(alloc)>::destroy(alloc, object);
                std::allocator_traits<decltype(alloc)>::deallocate(alloc, object, 1);
                break;
            }

            case value_t::array:
            {
                AllocatorType<array_t> alloc;
                std::allocator_traits<decltype(alloc)>::destroy(alloc, array);
                std::allocator_traits<decltype(alloc)>::deallocate(alloc, array, 1);
                break;
            }

            case value_t::string:
            {
                AllocatorType<string_t> alloc;
                std::allocator_traits<decltype(alloc)>::destroy(alloc, string);
                std::allocator_traits<decltype(alloc)>::deallocate(alloc, string, 1);
                break;
            }

            default:
            {
                break;
            }
            }
        }
    };

    void assert_invariant() const noexcept
    {
        assert(m_type != value_t::object or m_value.object != nullptr);
        assert(m_type != value_t::array or m_value.array != nullptr);
        assert(m_type != value_t::string or m_value.string != nullptr);
    }

public:
    // JSON parser callback //

    using parse_event_t = typename parser::parse_event_t;

    using parser_callback_t = typename parser::parser_callback_t;


    // constructors //


    basic_json(const value_t v)
        : m_type(v), m_value(v)
    {
        assert_invariant();
    }

    basic_json(std::nullptr_t = nullptr) noexcept
        : basic_json(value_t::null)
    {
        assert_invariant();
    }

    template<typename CompatibleType,
             typename U = detail::uncvref_t<CompatibleType>,
             detail::enable_if_t<
                 detail::is_compatible_type<basic_json_t, U>::value, int> = 0>
    basic_json(CompatibleType &&val) noexcept (noexcept (
                                                   JSONSerializer<U>::to_json(std::declval<basic_json_t &>(),
                                                                              std::forward<CompatibleType>(val))))
    {
        JSONSerializer<U>::to_json(*this, std::forward<CompatibleType>(val));
        assert_invariant();
    }

    basic_json(initializer_list_t init,
               bool type_deduction = true,
               value_t manual_type = value_t::array)
    {
        // check if each element is an array with two elements whose first
        // element is a string
        bool is_an_object = std::all_of(init.begin(), init.end(),
                                        [](const detail::json_ref<basic_json> &element_ref) {
                return (element_ref->is_array() and element_ref->size() == 2 and (*element_ref)[0].is_string());
            });

        // adjust type if type deduction is not wanted
        if (not type_deduction) {
            // if array is wanted, do not create an object though possible
            if (manual_type == value_t::array) {
                is_an_object = false;
            }

            // if object is wanted but impossible, throw an exception
            if (JSON_UNLIKELY(manual_type == value_t::object and not is_an_object)) {
                JSON_THROW(type_error::create(301, "cannot create object from initializer list"));
            }
        }

        if (is_an_object) {
            // the initializer list is a list of pairs -> create object
            m_type = value_t::object;
            m_value = value_t::object;

            std::for_each(init.begin(), init.end(), [this](const detail::json_ref<basic_json> &element_ref) {
                    auto element = element_ref.moved_or_copied();
                    m_value.object->emplace(
                        std::move(*((*element.m_value.array)[0].m_value.string)),
                        std::move((*element.m_value.array)[1]));
                });
        } else {
            // the initializer list describes an array -> create array
            m_type = value_t::array;
            m_value.array = create<array_t>(init.begin(), init.end());
        }

        assert_invariant();
    }

    static basic_json array(initializer_list_t init = {})
    {
        return basic_json(init, false, value_t::array);
    }

    static basic_json object(initializer_list_t init = {})
    {
        return basic_json(init, false, value_t::object);
    }

    basic_json(size_type cnt, const basic_json &val)
        : m_type(value_t::array)
    {
        m_value.array = create<array_t>(cnt, val);
        assert_invariant();
    }

    template<class InputIT, typename std::enable_if<
                 std::is_same<InputIT, typename basic_json_t::iterator>::value or
                 std::is_same<InputIT, typename basic_json_t::const_iterator>::value, int>::type = 0>
    basic_json(InputIT first, InputIT last)
    {
        assert(first.m_object != nullptr);
        assert(last.m_object != nullptr);

        // make sure iterator fits the current value
        if (JSON_UNLIKELY(first.m_object != last.m_object)) {
            JSON_THROW(invalid_iterator::create(201, "iterators are not compatible"));
        }

        // copy type from first iterator
        m_type = first.m_object->m_type;

        // check if iterator range is complete for primitive values
        switch (m_type) {
        case value_t::boolean:
        case value_t::number_float:
        case value_t::number_integer:
        case value_t::number_unsigned:
        case value_t::string:
        {
            if (JSON_UNLIKELY(not first.m_it.primitive_iterator.is_begin()
                              or not last.m_it.primitive_iterator.is_end())) {
                JSON_THROW(invalid_iterator::create(204, "iterators out of range"));
            }

            break;
        }

        default:
            break;
        }

        switch (m_type) {
        case value_t::number_integer:
        {
            m_value.number_integer = first.m_object->m_value.number_integer;
            break;
        }

        case value_t::number_unsigned:
        {
            m_value.number_unsigned = first.m_object->m_value.number_unsigned;
            break;
        }

        case value_t::number_float:
        {
            m_value.number_float = first.m_object->m_value.number_float;
            break;
        }

        case value_t::boolean:
        {
            m_value.boolean = first.m_object->m_value.boolean;
            break;
        }

        case value_t::string:
        {
            m_value = *first.m_object->m_value.string;
            break;
        }

        case value_t::object:
        {
            m_value.object = create<object_t>(first.m_it.object_iterator,
                                              last.m_it.object_iterator);
            break;
        }

        case value_t::array:
        {
            m_value.array = create<array_t>(first.m_it.array_iterator,
                                            last.m_it.array_iterator);
            break;
        }

        default:
            JSON_THROW(invalid_iterator::create(206, "cannot construct with iterators from " +
                                                std::string(first.m_object->type_name())));
        }

        assert_invariant();
    }


    // other constructors and destructor //

    basic_json(const detail::json_ref<basic_json> &ref)
        : basic_json(ref.moved_or_copied())
    {}

    basic_json(const basic_json &other)
        : m_type(other.m_type)
    {
        // check of passed value is valid
        other.assert_invariant();

        switch (m_type) {
        case value_t::object:
        {
            m_value = *other.m_value.object;
            break;
        }

        case value_t::array:
        {
            m_value = *other.m_value.array;
            break;
        }

        case value_t::string:
        {
            m_value = *other.m_value.string;
            break;
        }

        case value_t::boolean:
        {
            m_value = other.m_value.boolean;
            break;
        }

        case value_t::number_integer:
        {
            m_value = other.m_value.number_integer;
            break;
        }

        case value_t::number_unsigned:
        {
            m_value = other.m_value.number_unsigned;
            break;
        }

        case value_t::number_float:
        {
            m_value = other.m_value.number_float;
            break;
        }

        default:
            break;
        }

        assert_invariant();
    }

    basic_json(basic_json &&other) noexcept
        : m_type(std::move(other.m_type)), m_value(std::move(other.m_value))
    {
        // check that passed value is valid
        other.assert_invariant();

        // invalidate payload
        other.m_type = value_t::null;
        other.m_value = {};

        assert_invariant();
    }

    reference &operator=(basic_json other) noexcept (
        std::is_nothrow_move_constructible<value_t>::value and
        std::is_nothrow_move_assignable<value_t>::value and
        std::is_nothrow_move_constructible<json_value>::value and
        std::is_nothrow_move_assignable<json_value>::value
    )
    {
        // check that passed value is valid
        other.assert_invariant();

        using std::swap;
        swap(m_type, other.m_type);
        swap(m_value, other.m_value);

        assert_invariant();
        return *this;
    }

    ~basic_json() noexcept
    {
        assert_invariant();
        m_value.destroy(m_type);
    }


public:
    // object inspection //


    string_t dump(const int indent = -1, const char indent_char = ' ',
                  const bool ensure_ascii = false) const
    {
        string_t result;
        serializer s(detail::output_adapter<char>(result), indent_char);

        if (indent >= 0) {
            s.dump(*this, true, ensure_ascii, static_cast<unsigned int>(indent));
        } else {
            s.dump(*this, false, ensure_ascii, 0);
        }

        return result;
    }

    constexpr value_t type() const noexcept
    {
        return m_type;
    }

    constexpr bool is_primitive() const noexcept
    {
        return is_null() or is_string() or is_boolean() or is_number();
    }

    constexpr bool is_structured() const noexcept
    {
        return is_array() or is_object();
    }

    constexpr bool is_null() const noexcept
    {
        return (m_type == value_t::null);
    }

    constexpr bool is_boolean() const noexcept
    {
        return (m_type == value_t::boolean);
    }

    constexpr bool is_number() const noexcept
    {
        return is_number_integer() or is_number_float();
    }

    constexpr bool is_number_integer() const noexcept
    {
        return (m_type == value_t::number_integer or m_type == value_t::number_unsigned);
    }

    constexpr bool is_number_unsigned() const noexcept
    {
        return (m_type == value_t::number_unsigned);
    }

    constexpr bool is_number_float() const noexcept
    {
        return (m_type == value_t::number_float);
    }

    constexpr bool is_object() const noexcept
    {
        return (m_type == value_t::object);
    }

    constexpr bool is_array() const noexcept
    {
        return (m_type == value_t::array);
    }

    constexpr bool is_string() const noexcept
    {
        return (m_type == value_t::string);
    }

    constexpr bool is_discarded() const noexcept
    {
        return (m_type == value_t::discarded);
    }

    constexpr operator value_t() const noexcept
    {
        return m_type;
    }


private:
    // value access //

    boolean_t get_impl(boolean_t * /*unused*/) const
    {
        if (JSON_LIKELY(is_boolean())) {
            return m_value.boolean;
        }

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

    object_t *get_impl_ptr(object_t * /*unused*/) noexcept
    {
        return is_object() ? m_value.object : nullptr;
    }

    constexpr const object_t *get_impl_ptr(const object_t * /*unused*/) const noexcept
    {
        return is_object() ? m_value.object : nullptr;
    }

    array_t *get_impl_ptr(array_t * /*unused*/) noexcept
    {
        return is_array() ? m_value.array : nullptr;
    }

    constexpr const array_t *get_impl_ptr(const array_t * /*unused*/) const noexcept
    {
        return is_array() ? m_value.array : nullptr;
    }

    string_t *get_impl_ptr(string_t * /*unused*/) noexcept
    {
        return is_string() ? m_value.string : nullptr;
    }

    constexpr const string_t *get_impl_ptr(const string_t * /*unused*/) const noexcept
    {
        return is_string() ? m_value.string : nullptr;
    }

    boolean_t *get_impl_ptr(boolean_t * /*unused*/) noexcept
    {
        return is_boolean() ? &m_value.boolean : nullptr;
    }

    constexpr const boolean_t *get_impl_ptr(const boolean_t * /*unused*/) const noexcept
    {
        return is_boolean() ? &m_value.boolean : nullptr;
    }

    number_integer_t *get_impl_ptr(number_integer_t * /*unused*/) noexcept
    {
        return is_number_integer() ? &m_value.number_integer : nullptr;
    }

    constexpr const number_integer_t *get_impl_ptr(const number_integer_t * /*unused*/) const noexcept
    {
        return is_number_integer() ? &m_value.number_integer : nullptr;
    }

    number_unsigned_t *get_impl_ptr(number_unsigned_t * /*unused*/) noexcept
    {
        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
    }

    constexpr const number_unsigned_t *get_impl_ptr(const number_unsigned_t * /*unused*/) const noexcept
    {
        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
    }

    number_float_t *get_impl_ptr(number_float_t * /*unused*/) noexcept
    {
        return is_number_float() ? &m_value.number_float : nullptr;
    }

    constexpr const number_float_t *get_impl_ptr(const number_float_t * /*unused*/) const noexcept
    {
        return is_number_float() ? &m_value.number_float : nullptr;
    }

    template<typename ReferenceType, typename ThisType>
    static ReferenceType get_ref_impl(ThisType &obj)
    {
        // delegate the call to get_ptr<>()
        auto ptr = obj.template get_ptr<typename std::add_pointer<ReferenceType>::type>();

        if (JSON_LIKELY(ptr != nullptr)) {
            return *ptr;
        }

        JSON_THROW(type_error::create(303,
                                      "incompatible ReferenceType for get_ref, actual type is " +
                                      std::string(obj.type_name())));
    }

public:

    template<typename BasicJsonType, detail::enable_if_t<
                 std::is_same<typename std::remove_const<BasicJsonType>::type, basic_json_t>::value,
                 int> = 0>
    basic_json get() const
    {
        return *this;
    }

    template<typename ValueTypeCV, typename ValueType = detail::uncvref_t<ValueTypeCV>,
             detail::enable_if_t<
                 not std::is_same<basic_json_t, ValueType>::value and
                 detail::has_from_json<basic_json_t, ValueType>::value and
                 not detail::has_non_default_from_json<basic_json_t, ValueType>::value,
                 int> = 0>
    ValueType get() const noexcept (noexcept (
                                        JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t &>(),
                                                                             std::declval<ValueType &>())))
    {
        // we cannot static_assert on ValueTypeCV being non-const, because
        // there is support for get<const basic_json_t>(), which is why we
        // still need the uncvref
        static_assert(not std::is_reference<ValueTypeCV>::value,
                      "get() cannot be used with reference types, you might want to use get_ref()");
        static_assert(std::is_default_constructible<ValueType>::value,
                      "types must be DefaultConstructible when used with get()");

        ValueType ret;
        JSONSerializer<ValueType>::from_json(*this, ret);
        return ret;
    }

    template<typename ValueTypeCV, typename ValueType = detail::uncvref_t<ValueTypeCV>,
             detail::enable_if_t<not std::is_same<basic_json_t, ValueType>::value and
                                 detail::has_non_default_from_json<basic_json_t, ValueType>::value,
                                 int> = 0>
    ValueType get() const noexcept (noexcept (
                                        JSONSerializer<ValueTypeCV>::from_json(std::declval<const basic_json_t &>())))
    {
        static_assert(not std::is_reference<ValueTypeCV>::value,
                      "get() cannot be used with reference types, you might want to use get_ref()");
        return JSONSerializer<ValueTypeCV>::from_json(*this);
    }

    template<typename PointerType, typename std::enable_if<
                 std::is_pointer<PointerType>::value, int>::type = 0>
    PointerType get() noexcept
    {
        // delegate the call to get_ptr
        return get_ptr<PointerType>();
    }

    template<typename PointerType, typename std::enable_if<
                 std::is_pointer<PointerType>::value, int>::type = 0>
    constexpr const PointerType get() const noexcept
    {
        // delegate the call to get_ptr
        return get_ptr<PointerType>();
    }

    template<typename PointerType, typename std::enable_if<
                 std::is_pointer<PointerType>::value, int>::type = 0>
    PointerType get_ptr() noexcept
    {
        // get the type of the PointerType (remove pointer and const)
        using pointee_t = typename std::remove_const<typename
                                                     std::remove_pointer<typename
                                                                         std::remove_const<PointerType>::type>::type>
            ::type;
        // make sure the type matches the allowed types
        static_assert(
            std::is_same<object_t, pointee_t>::value
            or std::is_same<array_t, pointee_t>::value
            or std::is_same<string_t, pointee_t>::value
            or std::is_same<boolean_t, pointee_t>::value
            or std::is_same<number_integer_t, pointee_t>::value
            or std::is_same<number_unsigned_t, pointee_t>::value
            or std::is_same<number_float_t, pointee_t>::value
            , "incompatible pointer type");

        // delegate the call to get_impl_ptr<>()
        return get_impl_ptr(static_cast<PointerType>(nullptr));
    }

    template<typename PointerType, typename std::enable_if<
                 std::is_pointer<PointerType>::value and
                 std::is_const<typename std::remove_pointer<PointerType>::type>::value, int>::type = 0>
    constexpr const PointerType get_ptr() const noexcept
    {
        // get the type of the PointerType (remove pointer and const)
        using pointee_t = typename std::remove_const<typename
                                                     std::remove_pointer<typename
                                                                         std::remove_const<PointerType>::type>::type>
            ::type;
        // make sure the type matches the allowed types
        static_assert(
            std::is_same<object_t, pointee_t>::value
            or std::is_same<array_t, pointee_t>::value
            or std::is_same<string_t, pointee_t>::value
            or std::is_same<boolean_t, pointee_t>::value
            or std::is_same<number_integer_t, pointee_t>::value
            or std::is_same<number_unsigned_t, pointee_t>::value
            or std::is_same<number_float_t, pointee_t>::value
            , "incompatible pointer type");

        // delegate the call to get_impl_ptr<>() const
        return get_impl_ptr(static_cast<PointerType>(nullptr));
    }

    template<typename ReferenceType, typename std::enable_if<
                 std::is_reference<ReferenceType>::value, int>::type = 0>
    ReferenceType get_ref()
    {
        // delegate call to get_ref_impl
        return get_ref_impl<ReferenceType>(*this);
    }

    template<typename ReferenceType, typename std::enable_if<
                 std::is_reference<ReferenceType>::value and
                 std::is_const<typename std::remove_reference<ReferenceType>::type>::value, int>::type = 0>
    ReferenceType get_ref() const
    {
        // delegate call to get_ref_impl
        return get_ref_impl<ReferenceType>(*this);
    }

    template<typename ValueType, typename std::enable_if<
                 not std::is_pointer<ValueType>::value and
                 not std::is_same<ValueType, detail::json_ref<basic_json>>::value and
                 not std::is_same<ValueType, typename string_t::value_type>::value
#ifndef _MSC_VER  // fix for issue #167 operator<< ambiguity under VS2015
                 and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
#endif
#if defined(JSON_HAS_CPP_17)
                 and not std::is_same<ValueType, typename std::string_view>::value
#endif
                 , int>::type = 0>
    operator ValueType() const
    {
        // delegate the call to get<>() const
        return get<ValueType>();
    }



    // element access //


    reference at(size_type idx)
    {
        // at only works for arrays
        if (JSON_LIKELY(is_array())) {
            JSON_TRY
            {
                return m_value.array->at(idx);
            }
            JSON_CATCH(std::out_of_range &)
            {
                // create better exception explanation
                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(
                                                    idx) + " is out of range"));
            }
        } else {
            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
        }
    }

    const_reference at(size_type idx) const
    {
        // at only works for arrays
        if (JSON_LIKELY(is_array())) {
            JSON_TRY
            {
                return m_value.array->at(idx);
            }
            JSON_CATCH(std::out_of_range &)
            {
                // create better exception explanation
                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(
                                                    idx) + " is out of range"));
            }
        } else {
            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
        }
    }

    reference at(const typename object_t::key_type &key)
    {
        // at only works for objects
        if (JSON_LIKELY(is_object())) {
            JSON_TRY
            {
                return m_value.object->at(key);
            }
            JSON_CATCH(std::out_of_range &)
            {
                // create better exception explanation
                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found"));
            }
        } else {
            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
        }
    }

    const_reference at(const typename object_t::key_type &key) const
    {
        // at only works for objects
        if (JSON_LIKELY(is_object())) {
            JSON_TRY
            {
                return m_value.object->at(key);
            }
            JSON_CATCH(std::out_of_range &)
            {
                // create better exception explanation
                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found"));
            }
        } else {
            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
        }
    }

    reference operator[](size_type idx)
    {
        // implicitly convert null value to an empty array
        if (is_null()) {
            m_type = value_t::array;
            m_value.array = create<array_t>();
            assert_invariant();
        }

        // operator[] only works for arrays
        if (JSON_LIKELY(is_array())) {
            // fill up array with null values if given idx is outside range
            if (idx >= m_value.array->size()) {
                m_value.array->insert(m_value.array->end(),
                                      idx - m_value.array->size() + 1,
                                      basic_json());
            }

            return m_value.array->operator[](idx);
        }

        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
    }

    const_reference operator[](size_type idx) const
    {
        // const operator[] only works for arrays
        if (JSON_LIKELY(is_array())) {
            return m_value.array->operator[](idx);
        }

        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
    }

    reference operator[](const typename object_t::key_type &key)
    {
        // implicitly convert null value to an empty object
        if (is_null()) {
            m_type = value_t::object;
            m_value.object = create<object_t>();
            assert_invariant();
        }

        // operator[] only works for objects
        if (JSON_LIKELY(is_object())) {
            return m_value.object->operator[](key);
        }

        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
    }

    const_reference operator[](const typename object_t::key_type &key) const
    {
        // const operator[] only works for objects
        if (JSON_LIKELY(is_object())) {
            assert(m_value.object->find(key) != m_value.object->end());
            return m_value.object->find(key)->second;
        }

        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
    }

    template<typename T>
    reference operator[](T *key)
    {
        // implicitly convert null to object
        if (is_null()) {
            m_type = value_t::object;
            m_value = value_t::object;
            assert_invariant();
        }

        // at only works for objects
        if (JSON_LIKELY(is_object())) {
            return m_value.object->operator[](key);
        }

        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
    }

    template<typename T>
    const_reference operator[](T *key) const
    {
        // at only works for objects
        if (JSON_LIKELY(is_object())) {
            assert(m_value.object->find(key) != m_value.object->end());
            return m_value.object->find(key)->second;
        }

        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
    }

    template<class ValueType, typename std::enable_if<
                 std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0>
    ValueType value(const typename object_t::key_type &key, const ValueType &default_value) const
    {
        // at only works for objects
        if (JSON_LIKELY(is_object())) {
            // if key is found, return value and given default value otherwise
            const auto it = find(key);
            if (it != end()) {
                return *it;
            }

            return default_value;
        }

        JSON_THROW(type_error::create(306, "cannot use value() with " + std::string(type_name())));
    }

    string_t value(const typename object_t::key_type &key, const char *default_value) const
    {
        return value(key, string_t(default_value));
    }

    template<class ValueType, typename std::enable_if<
                 std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0>
    ValueType value(const json_pointer &ptr, const ValueType &default_value) const
    {
        // at only works for objects
        if (JSON_LIKELY(is_object())) {
            // if pointer resolves a value, return it or use default value
            JSON_TRY
            {
                return ptr.get_checked(this);
            }
            JSON_CATCH(out_of_range &)
            {
                return default_value;
            }
        }

        JSON_THROW(type_error::create(306, "cannot use value() with " + std::string(type_name())));
    }

    string_t value(const json_pointer &ptr, const char *default_value) const
    {
        return value(ptr, string_t(default_value));
    }

    reference front()
    {
        return *begin();
    }

    const_reference front() const
    {
        return *cbegin();
    }

    reference back()
    {
        auto tmp = end();
        --tmp;
        return *tmp;
    }

    const_reference back() const
    {
        auto tmp = cend();
        --tmp;
        return *tmp;
    }

    template<class IteratorType, typename std::enable_if<
                 std::is_same<IteratorType, typename basic_json_t::iterator>::value or
                 std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type
                 = 0>
    IteratorType erase(IteratorType pos)
    {
        // make sure iterator fits the current value
        if (JSON_UNLIKELY(this != pos.m_object)) {
            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
        }

        IteratorType result = end();

        switch (m_type) {
        case value_t::boolean:
        case value_t::number_float:
        case value_t::number_integer:
        case value_t::number_unsigned:
        case value_t::string:
        {
            if (JSON_UNLIKELY(not pos.m_it.primitive_iterator.is_begin())) {
                JSON_THROW(invalid_iterator::create(205, "iterator out of range"));
            }

            if (is_string()) {
                AllocatorType<string_t> alloc;
                std::allocator_traits<decltype(alloc)>::destroy(alloc, m_value.string);
                std::allocator_traits<decltype(alloc)>::deallocate(alloc, m_value.string, 1);
                m_value.string = nullptr;
            }

            m_type = value_t::null;
            assert_invariant();
            break;
        }

        case value_t::object:
        {
            result.m_it.object_iterator = m_value.object->erase(pos.m_it.object_iterator);
            break;
        }

        case value_t::array:
        {
            result.m_it.array_iterator = m_value.array->erase(pos.m_it.array_iterator);
            break;
        }

        default:
            JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
        }

        return result;
    }

    template<class IteratorType, typename std::enable_if<
                 std::is_same<IteratorType, typename basic_json_t::iterator>::value or
                 std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type
                 = 0>
    IteratorType erase(IteratorType first, IteratorType last)
    {
        // make sure iterator fits the current value
        if (JSON_UNLIKELY(this != first.m_object or this != last.m_object)) {
            JSON_THROW(invalid_iterator::create(203, "iterators do not fit current value"));
        }

        IteratorType result = end();

        switch (m_type) {
        case value_t::boolean:
        case value_t::number_float:
        case value_t::number_integer:
        case value_t::number_unsigned:
        case value_t::string:
        {
            if (JSON_LIKELY(not first.m_it.primitive_iterator.is_begin()
                            or not last.m_it.primitive_iterator.is_end())) {
                JSON_THROW(invalid_iterator::create(204, "iterators out of range"));
            }

            if (is_string()) {
                AllocatorType<string_t> alloc;
                std::allocator_traits<decltype(alloc)>::destroy(alloc, m_value.string);
                std::allocator_traits<decltype(alloc)>::deallocate(alloc, m_value.string, 1);
                m_value.string = nullptr;
            }

            m_type = value_t::null;
            assert_invariant();
            break;
        }

        case value_t::object:
        {
            result.m_it.object_iterator = m_value.object->erase(first.m_it.object_iterator,
                                                                last.m_it.object_iterator);
            break;
        }

        case value_t::array:
        {
            result.m_it.array_iterator = m_value.array->erase(first.m_it.array_iterator,
                                                              last.m_it.array_iterator);
            break;
        }

        default:
            JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
        }

        return result;
    }

    size_type erase(const typename object_t::key_type &key)
    {
        // this erase only works for objects
        if (JSON_LIKELY(is_object())) {
            return m_value.object->erase(key);
        }

        JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
    }

    void erase(const size_type idx)
    {
        // this erase only works for arrays
        if (JSON_LIKELY(is_array())) {
            if (JSON_UNLIKELY(idx >= size())) {
                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(
                                                    idx) + " is out of range"));
            }

            m_value.array->erase(m_value.array->begin() + static_cast<difference_type>(idx));
        } else {
            JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
        }
    }



    // lookup //


    template<typename KeyT>
    iterator find(KeyT &&key)
    {
        auto result = end();

        if (is_object()) {
            result.m_it.object_iterator = m_value.object->find(std::forward<KeyT>(key));
        }

        return result;
    }

    template<typename KeyT>
    const_iterator find(KeyT &&key) const
    {
        auto result = cend();

        if (is_object()) {
            result.m_it.object_iterator = m_value.object->find(std::forward<KeyT>(key));
        }

        return result;
    }

    template<typename KeyT>
    size_type count(KeyT &&key) const
    {
        // return 0 for all nonobject types
        return is_object() ? m_value.object->count(std::forward<KeyT>(key)) : 0;
    }



    // iterators //


    iterator begin() noexcept
    {
        iterator result(this);
        result.set_begin();
        return result;
    }

    const_iterator begin() const noexcept
    {
        return cbegin();
    }

    const_iterator cbegin() const noexcept
    {
        const_iterator result(this);
        result.set_begin();
        return result;
    }

    iterator end() noexcept
    {
        iterator result(this);
        result.set_end();
        return result;
    }

    const_iterator end() const noexcept
    {
        return cend();
    }

    const_iterator cend() const noexcept
    {
        const_iterator result(this);
        result.set_end();
        return result;
    }

    reverse_iterator rbegin() noexcept
    {
        return reverse_iterator(end());
    }

    const_reverse_iterator rbegin() const noexcept
    {
        return crbegin();
    }

    reverse_iterator rend() noexcept
    {
        return reverse_iterator(begin());
    }

    const_reverse_iterator rend() const noexcept
    {
        return crend();
    }

    const_reverse_iterator crbegin() const noexcept
    {
        return const_reverse_iterator(cend());
    }

    const_reverse_iterator crend() const noexcept
    {
        return const_reverse_iterator(cbegin());
    }

public:
    JSON_DEPRECATED
    static iteration_proxy<iterator> iterator_wrapper(reference ref) noexcept
    {
        return ref.items();
    }

    JSON_DEPRECATED
    static iteration_proxy<const_iterator> iterator_wrapper(const_reference ref) noexcept
    {
        return ref.items();
    }

    iteration_proxy<iterator> items() noexcept
    {
        return iteration_proxy<iterator>(*this);
    }

    iteration_proxy<const_iterator> items() const noexcept
    {
        return iteration_proxy<const_iterator>(*this);
    }



    // capacity //


    bool empty() const noexcept
    {
        switch (m_type) {
        case value_t::null:
        {
            // null values are empty
            return true;
        }

        case value_t::array:
        {
            // delegate call to array_t::empty()
            return m_value.array->empty();
        }

        case value_t::object:
        {
            // delegate call to object_t::empty()
            return m_value.object->empty();
        }

        default:
        {
            // all other types are nonempty
            return false;
        }
        }
    }

    size_type size() const noexcept
    {
        switch (m_type) {
        case value_t::null:
        {
            // null values are empty
            return 0;
        }

        case value_t::array:
        {
            // delegate call to array_t::size()
            return m_value.array->size();
        }

        case value_t::object:
        {
            // delegate call to object_t::size()
            return m_value.object->size();
        }

        default:
        {
            // all other types have size 1
            return 1;
        }
        }
    }

    size_type max_size() const noexcept
    {
        switch (m_type) {
        case value_t::array:
        {
            // delegate call to array_t::max_size()
            return m_value.array->max_size();
        }

        case value_t::object:
        {
            // delegate call to object_t::max_size()
            return m_value.object->max_size();
        }

        default:
        {
            // all other types have max_size() == size()
            return size();
        }
        }
    }



    // modifiers //


    void clear() noexcept
    {
        switch (m_type) {
        case value_t::number_integer:
        {
            m_value.number_integer = 0;
            break;
        }

        case value_t::number_unsigned:
        {
            m_value.number_unsigned = 0;
            break;
        }

        case value_t::number_float:
        {
            m_value.number_float = 0.0;
            break;
        }

        case value_t::boolean:
        {
            m_value.boolean = false;
            break;
        }

        case value_t::string:
        {
            m_value.string->clear();
            break;
        }

        case value_t::array:
        {
            m_value.array->clear();
            break;
        }

        case value_t::object:
        {
            m_value.object->clear();
            break;
        }

        default:
            break;
        }
    }

    void push_back(basic_json &&val)
    {
        // push_back only works for null objects or arrays
        if (JSON_UNLIKELY(not (is_null() or is_array()))) {
            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name())));
        }

        // transform null object into an array
        if (is_null()) {
            m_type = value_t::array;
            m_value = value_t::array;
            assert_invariant();
        }

        // add element to array (move semantics)
        m_value.array->push_back(std::move(val));
        // invalidate object
        val.m_type = value_t::null;
    }

    reference operator+=(basic_json &&val)
    {
        push_back(std::move(val));
        return *this;
    }

    void push_back(const basic_json &val)
    {
        // push_back only works for null objects or arrays
        if (JSON_UNLIKELY(not (is_null() or is_array()))) {
            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name())));
        }

        // transform null object into an array
        if (is_null()) {
            m_type = value_t::array;
            m_value = value_t::array;
            assert_invariant();
        }

        // add element to array
        m_value.array->push_back(val);
    }

    reference operator+=(const basic_json &val)
    {
        push_back(val);
        return *this;
    }

    void push_back(const typename object_t::value_type &val)
    {
        // push_back only works for null objects or objects
        if (JSON_UNLIKELY(not (is_null() or is_object()))) {
            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name())));
        }

        // transform null object into an object
        if (is_null()) {
            m_type = value_t::object;
            m_value = value_t::object;
            assert_invariant();
        }

        // add element to array
        m_value.object->insert(val);
    }

    reference operator+=(const typename object_t::value_type &val)
    {
        push_back(val);
        return *this;
    }

    void push_back(initializer_list_t init)
    {
        if (is_object() and init.size() == 2 and (*init.begin())->is_string()) {
            basic_json &&key = init.begin()->moved_or_copied();
            push_back(typename object_t::value_type(
                          std::move(key.get_ref<string_t &>()), (init.begin() + 1)->moved_or_copied()));
        } else {
            push_back(basic_json(init));
        }
    }

    reference operator+=(initializer_list_t init)
    {
        push_back(init);
        return *this;
    }

    template<class... Args>
    void emplace_back(Args && ... args)
    {
        // emplace_back only works for null objects or arrays
        if (JSON_UNLIKELY(not (is_null() or is_array()))) {
            JSON_THROW(type_error::create(311, "cannot use emplace_back() with " + std::string(type_name())));
        }

        // transform null object into an array
        if (is_null()) {
            m_type = value_t::array;
            m_value = value_t::array;
            assert_invariant();
        }

        // add element to array (perfect forwarding)
        m_value.array->emplace_back(std::forward<Args>(args) ...);
    }

    template<class... Args>
    std::pair<iterator, bool> emplace(Args && ... args)
    {
        // emplace only works for null objects or arrays
        if (JSON_UNLIKELY(not (is_null() or is_object()))) {
            JSON_THROW(type_error::create(311, "cannot use emplace() with " + std::string(type_name())));
        }

        // transform null object into an object
        if (is_null()) {
            m_type = value_t::object;
            m_value = value_t::object;
            assert_invariant();
        }

        // add element to array (perfect forwarding)
        auto res = m_value.object->emplace(std::forward<Args>(args) ...);
        // create result iterator and set iterator to the result of emplace
        auto it = begin();
        it.m_it.object_iterator = res.first;

        // return pair of iterator and boolean
        return { it, res.second };
    }

    iterator insert(const_iterator pos, const basic_json &val)
    {
        // insert only works for arrays
        if (JSON_LIKELY(is_array())) {
            // check if iterator pos fits to this JSON value
            if (JSON_UNLIKELY(pos.m_object != this)) {
                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
            }

            // insert to array and return iterator
            iterator result(this);
            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, val);
            return result;
        }

        JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
    }

    iterator insert(const_iterator pos, basic_json &&val)
    {
        return insert(pos, val);
    }

    iterator insert(const_iterator pos, size_type cnt, const basic_json &val)
    {
        // insert only works for arrays
        if (JSON_LIKELY(is_array())) {
            // check if iterator pos fits to this JSON value
            if (JSON_UNLIKELY(pos.m_object != this)) {
                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
            }

            // insert to array and return iterator
            iterator result(this);
            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, cnt, val);
            return result;
        }

        JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
    }

    iterator insert(const_iterator pos, const_iterator first, const_iterator last)
    {
        // insert only works for arrays
        if (JSON_UNLIKELY(not is_array())) {
            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
        }

        // check if iterator pos fits to this JSON value
        if (JSON_UNLIKELY(pos.m_object != this)) {
            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
        }

        // check if range iterators belong to the same JSON object
        if (JSON_UNLIKELY(first.m_object != last.m_object)) {
            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
        }

        if (JSON_UNLIKELY(first.m_object == this)) {
            JSON_THROW(invalid_iterator::create(211, "passed iterators may not belong to container"));
        }

        // insert to array and return iterator
        iterator result(this);
        result.m_it.array_iterator = m_value.array->insert(
                pos.m_it.array_iterator,
                first.m_it.array_iterator,
                last.m_it.array_iterator);
        return result;
    }

    iterator insert(const_iterator pos, initializer_list_t ilist)
    {
        // insert only works for arrays
        if (JSON_UNLIKELY(not is_array())) {
            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
        }

        // check if iterator pos fits to this JSON value
        if (JSON_UNLIKELY(pos.m_object != this)) {
            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
        }

        // insert to array and return iterator
        iterator result(this);
        result.m_it.array_iterator =
            m_value.array->insert(pos.m_it.array_iterator, ilist.begin(), ilist.end());
        return result;
    }

    void insert(const_iterator first, const_iterator last)
    {
        // insert only works for objects
        if (JSON_UNLIKELY(not is_object())) {
            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
        }

        // check if range iterators belong to the same JSON object
        if (JSON_UNLIKELY(first.m_object != last.m_object)) {
            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
        }

        // passed iterators must belong to objects
        if (JSON_UNLIKELY(not first.m_object->is_object())) {
            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to objects"));
        }

        m_value.object->insert(first.m_it.object_iterator, last.m_it.object_iterator);
    }

    void update(const_reference j)
    {
        // implicitly convert null value to an empty object
        if (is_null()) {
            m_type = value_t::object;
            m_value.object = create<object_t>();
            assert_invariant();
        }

        if (JSON_UNLIKELY(not is_object())) {
            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(type_name())));
        }

        if (JSON_UNLIKELY(not j.is_object())) {
            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(j.type_name())));
        }

        for (auto it = j.cbegin(); it != j.cend(); ++it) {
            m_value.object->operator[](it.key()) = it.value();
        }
    }

    void update(const_iterator first, const_iterator last)
    {
        // implicitly convert null value to an empty object
        if (is_null()) {
            m_type = value_t::object;
            m_value.object = create<object_t>();
            assert_invariant();
        }

        if (JSON_UNLIKELY(not is_object())) {
            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(type_name())));
        }

        // check if range iterators belong to the same JSON object
        if (JSON_UNLIKELY(first.m_object != last.m_object)) {
            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
        }

        // passed iterators must belong to objects
        if (JSON_UNLIKELY(not first.m_object->is_object()
                          or not first.m_object->is_object())) {
            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to objects"));
        }

        for (auto it = first; it != last; ++it) {
            m_value.object->operator[](it.key()) = it.value();
        }
    }

    void swap(reference other) noexcept (
        std::is_nothrow_move_constructible<value_t>::value and
        std::is_nothrow_move_assignable<value_t>::value and
        std::is_nothrow_move_constructible<json_value>::value and
        std::is_nothrow_move_assignable<json_value>::value
    )
    {
        std::swap(m_type, other.m_type);
        std::swap(m_value, other.m_value);
        assert_invariant();
    }

    void swap(array_t &other)
    {
        // swap only works for arrays
        if (JSON_LIKELY(is_array())) {
            std::swap(*(m_value.array), other);
        } else {
            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name())));
        }
    }

    void swap(object_t &other)
    {
        // swap only works for objects
        if (JSON_LIKELY(is_object())) {
            std::swap(*(m_value.object), other);
        } else {
            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name())));
        }
    }

    void swap(string_t &other)
    {
        // swap only works for strings
        if (JSON_LIKELY(is_string())) {
            std::swap(*(m_value.string), other);
        } else {
            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name())));
        }
    }


public:
    // lexicographical comparison operators //


    friend bool operator==(const_reference lhs, const_reference rhs) noexcept
    {
        const auto lhs_type = lhs.type();
        const auto rhs_type = rhs.type();

        if (lhs_type == rhs_type) {
            switch (lhs_type) {
            case value_t::array:
                return (*lhs.m_value.array == *rhs.m_value.array);

            case value_t::object:
                return (*lhs.m_value.object == *rhs.m_value.object);

            case value_t::null:
                return true;

            case value_t::string:
                return (*lhs.m_value.string == *rhs.m_value.string);

            case value_t::boolean:
                return (lhs.m_value.boolean == rhs.m_value.boolean);

            case value_t::number_integer:
                return (lhs.m_value.number_integer == rhs.m_value.number_integer);

            case value_t::number_unsigned:
                return (lhs.m_value.number_unsigned == rhs.m_value.number_unsigned);

            case value_t::number_float:
                return (lhs.m_value.number_float == rhs.m_value.number_float);

            default:
                return false;
            }
        } else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float) {
            return (static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float);
        } else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer) {
            return (lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer));
        } else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float) {
            return (static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float);
        } else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned) {
            return (lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned));
        } else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer) {
            return (static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer);
        } else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned) {
            return (lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned));
        }

        return false;
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator==(const_reference lhs, const ScalarType rhs) noexcept
    {
        return (lhs == basic_json(rhs));
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator==(const ScalarType lhs, const_reference rhs) noexcept
    {
        return (basic_json(lhs) == rhs);
    }

    friend bool operator!=(const_reference lhs, const_reference rhs) noexcept
    {
        return not (lhs == rhs);
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator!=(const_reference lhs, const ScalarType rhs) noexcept
    {
        return (lhs != basic_json(rhs));
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator!=(const ScalarType lhs, const_reference rhs) noexcept
    {
        return (basic_json(lhs) != rhs);
    }

    friend bool operator<(const_reference lhs, const_reference rhs) noexcept
    {
        const auto lhs_type = lhs.type();
        const auto rhs_type = rhs.type();

        if (lhs_type == rhs_type) {
            switch (lhs_type) {
            case value_t::array:
                return (*lhs.m_value.array) < (*rhs.m_value.array);

            case value_t::object:
                return *lhs.m_value.object < *rhs.m_value.object;

            case value_t::null:
                return false;

            case value_t::string:
                return *lhs.m_value.string < *rhs.m_value.string;

            case value_t::boolean:
                return lhs.m_value.boolean < rhs.m_value.boolean;

            case value_t::number_integer:
                return lhs.m_value.number_integer < rhs.m_value.number_integer;

            case value_t::number_unsigned:
                return lhs.m_value.number_unsigned < rhs.m_value.number_unsigned;

            case value_t::number_float:
                return lhs.m_value.number_float < rhs.m_value.number_float;

            default:
                return false;
            }
        } else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float) {
            return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float;
        } else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer) {
            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
        } else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float) {
            return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float;
        } else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned) {
            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned);
        } else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned) {
            return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_unsigned);
        } else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer) {
            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_integer;
        }

        // We only reach this line if we cannot compare values. In that case,
        // we compare types. Note we have to call the operator explicitly,
        // because MSVC has problems otherwise.
        return operator<(lhs_type, rhs_type);
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator<(const_reference lhs, const ScalarType rhs) noexcept
    {
        return (lhs < basic_json(rhs));
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator<(const ScalarType lhs, const_reference rhs) noexcept
    {
        return (basic_json(lhs) < rhs);
    }

    friend bool operator<=(const_reference lhs, const_reference rhs) noexcept
    {
        return not (rhs < lhs);
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator<=(const_reference lhs, const ScalarType rhs) noexcept
    {
        return (lhs <= basic_json(rhs));
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator<=(const ScalarType lhs, const_reference rhs) noexcept
    {
        return (basic_json(lhs) <= rhs);
    }

    friend bool operator>(const_reference lhs, const_reference rhs) noexcept
    {
        return not (lhs <= rhs);
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator>(const_reference lhs, const ScalarType rhs) noexcept
    {
        return (lhs > basic_json(rhs));
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator>(const ScalarType lhs, const_reference rhs) noexcept
    {
        return (basic_json(lhs) > rhs);
    }

    friend bool operator>=(const_reference lhs, const_reference rhs) noexcept
    {
        return not (lhs < rhs);
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator>=(const_reference lhs, const ScalarType rhs) noexcept
    {
        return (lhs >= basic_json(rhs));
    }

    template<typename ScalarType, typename std::enable_if<
                 std::is_scalar<ScalarType>::value, int>::type = 0>
    friend bool operator>=(const ScalarType lhs, const_reference rhs) noexcept
    {
        return (basic_json(lhs) >= rhs);
    }


    // serialization //


    friend std ::ostream &operator<<(std::ostream &o, const basic_json &j)
    {
        // read width member and use it as indentation parameter if nonzero
        const bool pretty_print = (o.width() > 0);
        const auto indentation = (pretty_print ? o.width() : 0);

        // reset width to 0 for subsequent calls to this stream
        o.width(0);

        // do the actual serialization
        serializer s(detail::output_adapter<char>(o), o.fill());
        s.dump(j, pretty_print, false, static_cast<unsigned int>(indentation));
        return o;
    }

    JSON_DEPRECATED
    friend std ::ostream &operator>>(const basic_json &j, std::ostream &o)
    {
        return o << j;
    }



    // deserialization //


    static basic_json parse(detail::input_adapter i,
                            const parser_callback_t cb = nullptr,
                            const bool allow_exceptions = true)
    {
        basic_json result;
        parser(i, cb, allow_exceptions).parse(true, result);
        return result;
    }

    static basic_json parse(detail::input_adapter &i,
                            const parser_callback_t cb = nullptr,
                            const bool allow_exceptions = true)
    {
        basic_json result;
        parser(i, cb, allow_exceptions).parse(true, result);
        return result;
    }

    static bool accept(detail::input_adapter i)
    {
        return parser(i).accept(true);
    }

    static bool accept(detail::input_adapter &i)
    {
        return parser(i).accept(true);
    }

    template<class IteratorType, typename std::enable_if<
                 std::is_base_of<
                     std::random_access_iterator_tag,
                     typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
    static basic_json parse(IteratorType first, IteratorType last,
                            const parser_callback_t cb = nullptr,
                            const bool allow_exceptions = true)
    {
        basic_json result;
        parser(detail::input_adapter(first, last), cb, allow_exceptions).parse(true, result);
        return result;
    }

    template<class IteratorType, typename std::enable_if<
                 std::is_base_of<
                     std::random_access_iterator_tag,
                     typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
    static bool accept(IteratorType first, IteratorType last)
    {
        return parser(detail::input_adapter(first, last)).accept(true);
    }

    JSON_DEPRECATED
    friend std ::istream &operator<<(basic_json &j, std::istream &i)
    {
        return operator>>(i, j);
    }

    friend std ::istream &operator>>(std::istream &i, basic_json &j)
    {
        parser(detail::input_adapter(i)).parse(false, j);
        return i;
    }


    // convenience functions //

    const char *type_name() const noexcept
    {
        {
            switch (m_type) {
            case value_t::null:
                return "null";
            case value_t::object:
                return "object";
            case value_t::array:
                return "array";
            case value_t::string:
                return "string";
            case value_t::boolean:
                return "boolean";
            case value_t::discarded:
                return "discarded";
            default:
                return "number";
            }
        }
    }

private:
    // member variables //

    value_t m_type = value_t::null;

    json_value m_value = {};

    // binary serialization/deserialization //


public:
    static std::vector<uint8_t> to_cbor(const basic_json &j)
    {
        std::vector<uint8_t> result;
        to_cbor(j, result);
        return result;
    }

    static void to_cbor(const basic_json &j, detail::output_adapter<uint8_t> o)
    {
        binary_writer<uint8_t>(o).write_cbor(j);
    }

    static void to_cbor(const basic_json &j, detail::output_adapter<char> o)
    {
        binary_writer<char>(o).write_cbor(j);
    }

    static std::vector<uint8_t> to_msgpack(const basic_json &j)
    {
        std::vector<uint8_t> result;
        to_msgpack(j, result);
        return result;
    }

    static void to_msgpack(const basic_json &j, detail::output_adapter<uint8_t> o)
    {
        binary_writer<uint8_t>(o).write_msgpack(j);
    }

    static void to_msgpack(const basic_json &j, detail::output_adapter<char> o)
    {
        binary_writer<char>(o).write_msgpack(j);
    }

    static std::vector<uint8_t> to_ubjson(const basic_json &j,
                                          const bool use_size = false,
                                          const bool use_type = false)
    {
        std::vector<uint8_t> result;
        to_ubjson(j, result, use_size, use_type);
        return result;
    }

    static void to_ubjson(const basic_json &j, detail::output_adapter<uint8_t> o,
                          const bool use_size = false, const bool use_type = false)
    {
        binary_writer<uint8_t>(o).write_ubjson(j, use_size, use_type);
    }

    static void to_ubjson(const basic_json &j, detail::output_adapter<char> o,
                          const bool use_size = false, const bool use_type = false)
    {
        binary_writer<char>(o).write_ubjson(j, use_size, use_type);
    }

    static basic_json from_cbor(detail::input_adapter i,
                                const bool strict = true)
    {
        return binary_reader(i).parse_cbor(strict);
    }

    template<typename A1, typename A2,
             detail::enable_if_t<std::is_constructible<detail::input_adapter, A1, A2>::value, int> = 0>
    static basic_json from_cbor(A1 &&a1, A2 &&a2, const bool strict = true)
    {
        return binary_reader(detail::input_adapter(std::forward<A1>(a1), std::forward<A2>(a2))).parse_cbor(
            strict);
    }

    static basic_json from_msgpack(detail::input_adapter i,
                                   const bool strict = true)
    {
        return binary_reader(i).parse_msgpack(strict);
    }

    template<typename A1, typename A2,
             detail::enable_if_t<std::is_constructible<detail::input_adapter, A1, A2>::value, int> = 0>
    static basic_json from_msgpack(A1 &&a1, A2 &&a2, const bool strict = true)
    {
        return binary_reader(detail::input_adapter(std::forward<A1>(a1), std::forward<A2>(a2))).parse_msgpack(
            strict);
    }

    static basic_json from_ubjson(detail::input_adapter i,
                                  const bool strict = true)
    {
        return binary_reader(i).parse_ubjson(strict);
    }

    template<typename A1, typename A2,
             detail::enable_if_t<std::is_constructible<detail::input_adapter, A1, A2>::value, int> = 0>
    static basic_json from_ubjson(A1 &&a1, A2 &&a2, const bool strict = true)
    {
        return binary_reader(detail::input_adapter(std::forward<A1>(a1), std::forward<A2>(a2))).parse_ubjson(
            strict);
    }


    // JSON Pointer support //


    reference operator[](const json_pointer &ptr)
    {
        return ptr.get_unchecked(this);
    }

    const_reference operator[](const json_pointer &ptr) const
    {
        return ptr.get_unchecked(this);
    }

    reference at(const json_pointer &ptr)
    {
        return ptr.get_checked(this);
    }

    const_reference at(const json_pointer &ptr) const
    {
        return ptr.get_checked(this);
    }

    basic_json flatten() const
    {
        basic_json result(value_t::object);
        json_pointer::flatten("", *this, result);
        return result;
    }

    basic_json unflatten() const
    {
        return json_pointer::unflatten(*this);
    }


    // JSON Patch functions //


    basic_json patch(const basic_json &json_patch) const
    {
        // make a working copy to apply the patch to
        basic_json result = *this;

        // the valid JSON Patch operations
        enum class patch_operations { add, remove, replace, move, copy, test, invalid };

        const auto get_op = [](const std::string &op) {
                if (op == "add") {
                    return patch_operations::add;
                }

                if (op == "remove") {
                    return patch_operations::remove;
                }

                if (op == "replace") {
                    return patch_operations::replace;
                }

                if (op == "move") {
                    return patch_operations::move;
                }

                if (op == "copy") {
                    return patch_operations::copy;
                }

                if (op == "test") {
                    return patch_operations::test;
                }

                return patch_operations::invalid;
            };

        // wrapper for "add" operation; add value at ptr
        const auto operation_add = [&result](json_pointer &ptr, basic_json val) {
                // adding to the root of the target document means replacing it
                if (ptr.is_root()) {
                    result = val;
                } else {
                    // make sure the top element of the pointer exists
                    json_pointer top_pointer = ptr.top();
                    if (top_pointer != ptr) {
                        result.at(top_pointer);
                    }

                    // get reference to parent of JSON pointer ptr
                    const auto last_path = ptr.pop_back();
                    basic_json &parent = result[ptr];

                    switch (parent.m_type) {
                    case value_t::null:
                    case value_t::object:
                    {
                        // use operator[] to add value
                        parent[last_path] = val;
                        break;
                    }

                    case value_t::array:
                    {
                        if (last_path == "-") {
                            // special case: append to back
                            parent.push_back(val);
                        } else {
                            const auto idx = json_pointer::array_index(last_path);
                            if (JSON_UNLIKELY(static_cast<size_type>(idx) > parent.size())) {
                                // avoid undefined behavior
                                JSON_THROW(out_of_range::create(401,
                                                                "array index " + std::to_string(idx) +
                                                                " is out of range"));
                            } else {
                                // default case: insert add offset
                                parent.insert(parent.begin() + static_cast<difference_type>(idx), val);
                            }
                        }

                        break;
                    }

                    default:
                    {
                        // if there exists a parent it cannot be primitive
                        assert(false);  // LCOV_EXCL_LINE
                    }
                    }
                }
            };

        // wrapper for "remove" operation; remove value at ptr
        const auto operation_remove = [&result](json_pointer &ptr) {
                // get reference to parent of JSON pointer ptr
                const auto last_path = ptr.pop_back();
                basic_json &parent = result.at(ptr);

                // remove child
                if (parent.is_object()) {
                    // perform range check
                    auto it = parent.find(last_path);
                    if (JSON_LIKELY(it != parent.end())) {
                        parent.erase(it);
                    } else {
                        JSON_THROW(out_of_range::create(403, "key '" + last_path + "' not found"));
                    }
                } else if (parent.is_array()) {
                    // note erase performs range check
                    parent.erase(static_cast<size_type>(json_pointer::array_index(last_path)));
                }
            };

        // type check: top level value must be an array
        if (JSON_UNLIKELY(not json_patch.is_array())) {
            JSON_THROW(parse_error::create(104, 0, "JSON patch must be an array of objects"));
        }

        // iterate and apply the operations
        for (const auto &val : json_patch) {
            // wrapper to get a value for an operation
            const auto get_value = [&val](const std::string &op,
                                          const std::string &member,
                                          bool string_type) -> basic_json & {
                    // find value
                    auto it = val.m_value.object->find(member);

                    // context-sensitive error message
                    const auto error_msg = (op == "op") ? "operation" : "operation '" + op + "'";

                    // check if desired value is present
                    if (JSON_UNLIKELY(it == val.m_value.object->end())) {
                        JSON_THROW(parse_error::create(105, 0,
                                                       error_msg + " must have member '" + member + "'"));
                    }

                    // check if result is of type string
                    if (JSON_UNLIKELY(string_type and not it->second.is_string())) {
                        JSON_THROW(parse_error::create(105, 0,
                                                       error_msg + " must have string member '" + member +
                                                       "'"));
                    }

                    // no error: return value
                    return it->second;
                };

            // type check: every element of the array must be an object
            if (JSON_UNLIKELY(not val.is_object())) {
                JSON_THROW(parse_error::create(104, 0, "JSON patch must be an array of objects"));
            }

            // collect mandatory members
            const std::string op = get_value("op", "op", true);
            const std::string path = get_value(op, "path", true);
            json_pointer ptr(path);

            switch (get_op(op)) {
            case patch_operations::add:
            {
                operation_add(ptr, get_value("add", "value", false));
                break;
            }

            case patch_operations::remove:
            {
                operation_remove(ptr);
                break;
            }

            case patch_operations::replace:
            {
                // the "path" location must exist - use at()
                result.at(ptr) = get_value("replace", "value", false);
                break;
            }

            case patch_operations::move:
            {
                const std::string from_path = get_value("move", "from", true);
                json_pointer from_ptr(from_path);

                // the "from" location must exist - use at()
                basic_json v = result.at(from_ptr);

                // The move operation is functionally identical to a
                // "remove" operation on the "from" location, followed
                // immediately by an "add" operation at the target
                // location with the value that was just removed.
                operation_remove(from_ptr);
                operation_add(ptr, v);
                break;
            }

            case patch_operations::copy:
            {
                const std::string from_path = get_value("copy", "from", true);
                const json_pointer from_ptr(from_path);

                // the "from" location must exist - use at()
                basic_json v = result.at(from_ptr);

                // The copy is functionally identical to an "add"
                // operation at the target location using the value
                // specified in the "from" member.
                operation_add(ptr, v);
                break;
            }

            case patch_operations::test:
            {
                bool success = false;
                JSON_TRY
                {
                    // check if "value" matches the one at "path"
                    // the "path" location must exist - use at()
                    success = (result.at(ptr) == get_value("test", "value", false));
                }
                JSON_CATCH(out_of_range &)
                {
                    // ignore out of range errors: success remains false
                }

                // throw an exception if test fails
                if (JSON_UNLIKELY(not success)) {
                    JSON_THROW(other_error::create(501, "unsuccessful: " + val.dump()));
                }

                break;
            }

            case patch_operations::invalid:
            {
                // op must be "add", "remove", "replace", "move", "copy", or
                // "test"
                JSON_THROW(parse_error::create(105, 0, "operation value '" + op + "' is invalid"));
            }
            }
        }

        return result;
    }

    static basic_json diff(const basic_json &source, const basic_json &target,
                           const std::string &path = "")
    {
        // the patch
        basic_json result(value_t::array);

        // if the values are the same, return empty patch
        if (source == target) {
            return result;
        }

        if (source.type() != target.type()) {
            // different types: replace value
            result.push_back(
                {
                    { "op", "replace" }, { "path", path }, { "value", target }
                });
        } else {
            switch (source.type()) {
            case value_t::array:
            {
                // first pass: traverse common elements
                std::size_t i = 0;
                while (i < source.size() and i < target.size()) {
                    // recursive call to compare array values at index i
                    auto temp_diff = diff(source[i], target[i], path + "/" + std::to_string(i));
                    result.insert(result.end(), temp_diff.begin(), temp_diff.end());
                    ++i;
                }

                // i now reached the end of at least one array
                // in a second pass, traverse the remaining elements

                // remove my remaining elements
                const auto end_index = static_cast<difference_type>(result.size());
                while (i < source.size()) {
                    // add operations in reverse order to avoid invalid
                    // indices
                    result.insert(result.begin() + end_index, object(
                            {
                                { "op", "remove" },
                                { "path", path + "/" + std::to_string(i) }
                            }));
                    ++i;
                }

                // add other remaining elements
                while (i < target.size()) {
                    result.push_back(
                            {
                                { "op", "add" },
                                { "path", path + "/" + std::to_string(i) },
                                { "value", target[i] }
                            });
                    ++i;
                }

                break;
            }

            case value_t::object:
            {
                // first pass: traverse this object's elements
                for (auto it = source.cbegin(); it != source.cend(); ++it) {
                    // escape the key name to be used in a JSON patch
                    const auto key = json_pointer::escape(it.key());

                    if (target.find(it.key()) != target.end()) {
                        // recursive call to compare object values at key it
                        auto temp_diff = diff(it.value(), target[it.key()], path + "/" + key);
                        result.insert(result.end(), temp_diff.begin(), temp_diff.end());
                    } else {
                        // found a key that is not in o -> remove it
                        result.push_back(object(
                                {
                                    { "op", "remove" }, { "path", path + "/" + key }
                                }));
                    }
                }

                // second pass: traverse other object's elements
                for (auto it = target.cbegin(); it != target.cend(); ++it) {
                    if (source.find(it.key()) == source.end()) {
                        // found a key that is not in this -> add it
                        const auto key = json_pointer::escape(it.key());
                        result.push_back(
                                {
                                    { "op", "add" }, { "path", path + "/" + key },
                                    { "value", it.value() }
                                });
                    }
                }

                break;
            }

            default:
            {
                // both primitive type: replace value
                result.push_back(
                        {
                            { "op", "replace" }, { "path", path }, { "value", target }
                        });
                break;
            }
            }
        }

        return result;
    }


    // JSON Merge Patch functions //


    void merge_patch(const basic_json &patch)
    {
        if (patch.is_object()) {
            if (not is_object()) {
                *this = object();
            }

            for (auto it = patch.begin(); it != patch.end(); ++it) {
                if (it.value().is_null()) {
                    erase(it.key());
                } else {
                    operator[](it.key()).merge_patch(it.value());
                }
            }
        } else {
            *this = patch;
        }
    }

};

} // namespace nlohmann

// nonmember support //

// specialization of std::swap, and std::hash
namespace std
{
template<>
inline void swap(nlohmann::json &j1,
                 nlohmann::json &j2) noexcept (
    is_nothrow_move_constructible<nlohmann::json>::value and
    is_nothrow_move_assignable<nlohmann::json>::value
)
{
    j1.swap(j2);
}

template<>
struct hash<nlohmann::json>
{
    std::size_t operator()(const nlohmann::json &j) const
    {
        // a naive hashing via the string representation
        const auto &h = hash<nlohmann::json::string_t>();
        return h(j.dump());
    }
};

template<>
struct less<::nlohmann::detail::value_t>
{
    bool operator()(nlohmann::detail::value_t lhs,
                    nlohmann::detail::value_t rhs) const noexcept
    {
        return nlohmann::detail::operator<(lhs, rhs);
    }
};

} // namespace std

inline nlohmann::json operator"" _json(const char *s, std::size_t n)
{
    return nlohmann::json::parse(s, s + n);
}

inline nlohmann::json::json_pointer operator"" _json_pointer(const char *s, std::size_t n)
{
    return nlohmann::json::json_pointer(std::string(s, n));
}

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


// restore GCC/clang diagnostic settings
#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
    #pragma GCC diagnostic pop
#endif
#if defined(__clang__)
    #pragma GCC diagnostic pop
#endif

// clean up
#undef JSON_CATCH
#undef JSON_THROW
#undef JSON_TRY
#undef JSON_LIKELY
#undef JSON_UNLIKELY
#undef JSON_DEPRECATED
#undef JSON_HAS_CPP_14
#undef JSON_HAS_CPP_17
#undef NLOHMANN_BASIC_JSON_TPL_DECLARATION
#undef NLOHMANN_BASIC_JSON_TPL
#undef NLOHMANN_JSON_HAS_HELPER


#endif