nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value Union Reference

a JSON value More...

Public Member Functions
	json_value ()=default
	default constructor (for null values) More...
	json_value (boolean_t v) noexcept
	constructor for booleans More...
	json_value (number_integer_t v) noexcept
	constructor for numbers (integer) More...
	json_value (number_unsigned_t v) noexcept
	constructor for numbers (unsigned) More...
	json_value (number_float_t v) noexcept
	constructor for numbers (floating-point) More...
	json_value (value_t t)
	constructor for empty values of a given type More...
	json_value (const string_t &value)
	constructor for strings More...
	json_value (string_t &&value)
	constructor for rvalue strings More...
	json_value (const object_t &value)
	constructor for objects More...
	json_value (object_t &&value)
	constructor for rvalue objects More...
	json_value (const array_t &value)
	constructor for arrays More...
	json_value (array_t &&value)
	constructor for rvalue arrays More...
void	destroy (value_t t) noexcept

Public Attributes
object_t *	object
	object (stored with pointer to save storage) More...
array_t *	array
	array (stored with pointer to save storage) More...
string_t *	string
	string (stored with pointer to save storage) More...
boolean_t	boolean
	boolean More...
number_integer_t	number_integer
	number (integer) More...
number_unsigned_t	number_unsigned
	number (unsigned integer) More...
number_float_t	number_float
	number (floating-point) More...

Detailed Description

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>
union nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value

a JSON value

The actual storage for a JSON value of the basic_json class. This union combines the different storage types for the JSON value types defined in value_t.

JSON type	value_t type	used type
object	object	pointer to object_t
array	array	pointer to array_t
string	string	pointer to string_t
boolean	boolean	boolean_t
number	number_integer	number_integer_t
number	number_unsigned	number_unsigned_t
number	number_float	number_float_t
null	null	no value is stored

Note

Variable-length types (objects, arrays, and strings) are stored as pointers. The size of the union should not exceed 64 bits if the default value types are used.

Since

version 1.0.0

Definition at line 15414 of file json.hpp.

Constructor & Destructor Documentation

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( )

default

default constructor (for null values)

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( boolean_t  v )

inlinenoexcept

constructor for booleans

Definition at line 15434 of file json.hpp.

: boolean(v) {}

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( number_integer_t  v )

inlinenoexcept

constructor for numbers (integer)

Definition at line 15436 of file json.hpp.

: number_integer(v) {}

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( number_unsigned_t  v )

inlinenoexcept

constructor for numbers (unsigned)

Definition at line 15438 of file json.hpp.

: number_unsigned(v) {}

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( number_float_t  v )

inlinenoexcept

constructor for numbers (floating-point)

Definition at line 15440 of file json.hpp.

: number_float(v) {}

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( value_t  t )

inline

constructor for empty values of a given type

Definition at line 15442 of file json.hpp.

        {
            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_HEDLEY_UNLIKELY(t == value_t::null))
                    {
                        JSON_THROW(other_error::create(500, "961c151d2e87f2686a955a9be24d316f1362bf21 3.7.3")); // LCOV_EXCL_LINE
                    }
                    break;
                }
            }
        }

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( const string_t &  value )

inline

constructor for strings

Definition at line 15507 of file json.hpp.

        {
            string = create<string_t>(value);
        }

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( string_t &&  value )

inline

constructor for rvalue strings

Definition at line 15513 of file json.hpp.

        {
            string = create<string_t>(std::move(value));
        }

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( const object_t &  value )

inline

constructor for objects

Definition at line 15519 of file json.hpp.

        {
            object = create<object_t>(value);
        }

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( object_t &&  value )

inline

constructor for rvalue objects

Definition at line 15525 of file json.hpp.

        {
            object = create<object_t>(std::move(value));
        }

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( const array_t &  value )

inline

constructor for arrays

Definition at line 15531 of file json.hpp.

        {
            array = create<array_t>(value);
        }

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>

nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::json_value ( array_t &&  value )

inline

constructor for rvalue arrays

Definition at line 15537 of file json.hpp.

        {
            array = create<array_t>(std::move(value));
        }

Member Function Documentation

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>

void nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::destroy ( value_t  t )

inlinenoexcept

Definition at line 15542 of file json.hpp.

        {
            // flatten the current json_value to a heap-allocated stack
            std::vector<basic_json> stack;

            // move the top-level items to stack
            if (t == value_t::array)
            {
                stack.reserve(array->size());
                std::move(array->begin(), array->end(), std::back_inserter(stack));
            }
            else if (t == value_t::object)
            {
                stack.reserve(object->size());
                for (auto&& it : *object)
                {
                    stack.push_back(std::move(it.second));
                }
            }

            while (not stack.empty())
            {
                // move the last item to local variable to be processed
                basic_json current_item(std::move(stack.back()));
                stack.pop_back();

                // if current_item is array/object, move
                // its children to the stack to be processed later
                if (current_item.is_array())
                {
                    std::move(current_item.m_value.array->begin(), current_item.m_value.array->end(),
                              std::back_inserter(stack));

                    current_item.m_value.array->clear();
                }
                else if (current_item.is_object())
                {
                    for (auto&& it : *current_item.m_value.object)
                    {
                        stack.push_back(std::move(it.second));
                    }

                    current_item.m_value.object->clear();
                }

                // it's now safe that current_item get destructed
                // since it doesn't have any children
            }

            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;
                }
            }
        }

Member Data Documentation

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>

array_t* nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::array

array (stored with pointer to save storage)

Definition at line 15419 of file json.hpp.

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>

boolean_t nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::boolean

boolean

Definition at line 15423 of file json.hpp.

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>

number_float_t nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::number_float

number (floating-point)

Definition at line 15429 of file json.hpp.

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>

number_integer_t nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::number_integer

number (integer)

Definition at line 15425 of file json.hpp.

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>

number_unsigned_t nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::number_unsigned

number (unsigned integer)

Definition at line 15427 of file json.hpp.

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>

object_t* nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::object

object (stored with pointer to save storage)

Definition at line 15417 of file json.hpp.

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>

string_t* nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::json_value::string

string (stored with pointer to save storage)

Definition at line 15421 of file json.hpp.

---

The documentation for this union was generated from the following file:

• json.hpp