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renamed class from "JSON" to "son"
This commit is contained in:
Niels
439
src/json.h
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439
src/json.h
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/*!
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@file
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@copyright The code is licensed under the MIT License
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<http://opensource.org/licenses/MIT>,
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Copyright (c) 2013-2014 Niels Lohmann.
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@author Niels Lohmann <http://nlohmann.me>
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@see https://github.com/nlohmann/json
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*/
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#pragma once
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#include <initializer_list> // std::initializer_list
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#include <iostream> // std::istream, std::ostream
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#include <map> // std::map
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#include <mutex> // std::mutex
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#include <string> // std::string
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#include <vector> // std::vector
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/*!
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@brief JSON for Modern C++
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The size of a JSON object is 16 bytes: 8 bytes for the value union whose
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largest item is a pointer type and another 8 byte for an element of the
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type union. The latter only needs 1 byte - the remaining 7 bytes are wasted
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due to alignment.
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@see http://stackoverflow.com/questions/7758580/writing-your-own-stl-container/7759622#7759622
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@bug Numbers are currently handled too generously. There are several formats
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that are forbidden by the standard, but are accepted by the parser.
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@todo Implement json::swap()
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@todo Implement json::insert(), json::emplace(), json::emplace_back, json::erase
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@todo Implement json::reverse_iterator, json::const_reverse_iterator,
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json::rbegin(), json::rend(), json::crbegin(), json::crend()?
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*/
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class json
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{
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// forward declaration to friend this class
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public:
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class iterator;
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class const_iterator;
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public:
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/// possible types of a JSON object
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enum class value_type : uint8_t
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{
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/// ordered collection of values
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array = 0,
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/// unordered set of name/value pairs
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object,
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/// null value
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null,
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/// string value
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string,
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/// Boolean value
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boolean,
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/// number value (integer)
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number,
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/// number value (float)
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number_float
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};
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/// a type for an object
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using object_t = std::map<std::string, json>;
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/// a type for an array
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using array_t = std::vector<json>;
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/// a type for a string
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using string_t = std::string;
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/// a type for a Boolean
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using boolean_t = bool;
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/// a type for an integer number
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using number_t = int;
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/// a type for a floating point number
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using number_float_t = double;
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/// a type for list initialization
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using list_init_t = std::initializer_list<json>;
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/// a JSON value
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union value
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{
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/// array as pointer to array_t
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array_t* array;
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/// object as pointer to object_t
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object_t* object;
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/// string as pointer to string_t
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string_t* string;
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/// Boolean
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boolean_t boolean;
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/// number (integer)
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number_t number;
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/// number (float)
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number_float_t number_float;
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/// default constructor
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value() = default;
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/// constructor for arrays
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value(array_t*);
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/// constructor for objects
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value(object_t*);
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/// constructor for strings
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value(string_t*);
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/// constructor for Booleans
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value(boolean_t);
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/// constructor for numbers (integer)
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value(number_t);
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/// constructor for numbers (float)
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value(number_float_t);
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};
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public:
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/// create an object according to given type
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json(const value_type) noexcept;
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/// create a null object
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json() = default;
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/// create a null object
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json(std::nullptr_t) noexcept;
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/// create a string object from a C++ string
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json(const std::string&) noexcept;
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/// create a string object from a C++ string (move)
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json(std::string&&) noexcept;
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/// create a string object from a C string
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json(const char*) noexcept;
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/// create a Boolean object
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json(const bool) noexcept;
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/// create a number object
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json(const int) noexcept;
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/// create a number object
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json(const double) noexcept;
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/// create an array
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json(const array_t&) noexcept;
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/// create an array (move)
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json(array_t&&) noexcept;
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/// create an object
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json(const object_t&) noexcept;
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/// create an object (move)
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json(object_t&&) noexcept;
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/// create from an initializer list (to an array or object)
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json(list_init_t) noexcept;
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/// copy constructor
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json(const json&) noexcept;
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/// move constructor
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json(json&&) noexcept;
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/// copy assignment
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json& operator=(json) noexcept;
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/// destructor
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~json() noexcept;
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/// create from string representation
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static json parse(const std::string&);
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/// create from string representation
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static json parse(const char*);
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private:
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/// return the type as string
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const std::string _typename() const noexcept;
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public:
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/// explicit value conversion
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template<typename T>
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T get() const;
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/// implicit conversion to string representation
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operator const std::string() const;
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/// implicit conversion to integer (only for numbers)
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operator int() const;
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/// implicit conversion to double (only for numbers)
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operator double() const;
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/// implicit conversion to Boolean (only for Booleans)
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operator bool() const;
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/// implicit conversion to JSON vector (not for objects)
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operator array_t() const;
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/// implicit conversion to JSON map (only for objects)
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operator object_t() const;
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/// write to stream
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friend std::ostream& operator<<(std::ostream& o, const json& j)
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{
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o << j.toString();
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return o;
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}
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/// write to stream
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friend std::ostream& operator>>(const json& j, std::ostream& o)
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{
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o << j.toString();
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return o;
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}
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/// read from stream
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friend std::istream& operator>>(std::istream& i, json& j)
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{
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j = parser(i).parse();
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return i;
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}
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/// read from stream
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friend std::istream& operator<<(json& j, std::istream& i)
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{
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j = parser(i).parse();
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return i;
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}
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/// explicit conversion to string representation (C++ style)
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const std::string toString() const noexcept;
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/// add an object/array to an array
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json& operator+=(const json&);
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/// add a string to an array
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json& operator+=(const std::string&);
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/// add a null object to an array
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json& operator+=(const std::nullptr_t);
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/// add a string to an array
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json& operator+=(const char*);
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/// add a Boolean to an array
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json& operator+=(bool);
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/// add a number to an array
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json& operator+=(int);
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/// add a number to an array
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json& operator+=(double);
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/// add a pair to an object
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json& operator+=(const object_t::value_type&);
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/// add a list of elements to array or list of pairs to object
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json& operator+=(list_init_t);
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/// add an object/array to an array
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void push_back(const json&);
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/// add an object/array to an array (move)
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void push_back(json&&);
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/// add a string to an array
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void push_back(const std::string&);
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/// add a null object to an array
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void push_back(const std::nullptr_t);
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/// add a string to an array
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void push_back(const char*);
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/// add a Boolean to an array
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void push_back(bool);
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/// add a number to an array
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void push_back(int);
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/// add a number to an array
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void push_back(double);
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/// add a pair to an object
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void push_back(const object_t::value_type&);
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/// add a list of elements to array or list of pairs to object
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void push_back(list_init_t);
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/// operator to set an element in an array
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json& operator[](const int);
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/// operator to get an element in an array
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const json& operator[](const int) const;
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/// operator to get an element in an array
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json& at(const int);
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/// operator to get an element in an array
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const json& at(const int) const;
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/// operator to set an element in an object
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json& operator[](const std::string&);
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/// operator to set an element in an object
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json& operator[](const char*);
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/// operator to get an element in an object
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const json& operator[](const std::string&) const;
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/// operator to set an element in an object
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json& at(const std::string&);
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/// operator to set an element in an object
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json& at(const char*);
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/// operator to get an element in an object
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const json& at(const std::string&) const;
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/// operator to get an element in an object
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const json& at(const char*) const;
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/// return the number of stored values
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size_t size() const noexcept;
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/// checks whether object is empty
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bool empty() const noexcept;
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/// removes all elements from compounds and resets values to default
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void clear() noexcept;
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/// return the type of the object
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value_type type() const noexcept;
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/// find an element in an object (returns end() iterator otherwise)
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iterator find(const std::string&);
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/// find an element in an object (returns end() iterator otherwise)
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const_iterator find(const std::string&) const;
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/// find an element in an object (returns end() iterator otherwise)
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iterator find(const char*);
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/// find an element in an object (returns end() iterator otherwise)
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const_iterator find(const char*) const;
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/// lexicographically compares the values
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bool operator==(const json&) const noexcept;
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/// lexicographically compares the values
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bool operator!=(const json&) const noexcept;
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/// returns an iterator to the beginning (array/object)
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iterator begin() noexcept;
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/// returns an iterator to the end (array/object)
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iterator end() noexcept;
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/// returns an iterator to the beginning (array/object)
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const_iterator begin() const noexcept;
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/// returns an iterator to the end (array/object)
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const_iterator end() const noexcept;
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/// returns an iterator to the beginning (array/object)
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const_iterator cbegin() const noexcept;
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/// returns an iterator to the end (array/object)
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const_iterator cend() const noexcept;
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private:
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/// the type of this object
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value_type _type = value_type::null;
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/// the payload
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value _value {};
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private:
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/// mutex to guard payload
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static std::mutex _token;
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public:
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/// an iterator
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class iterator
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{
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friend class json;
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friend class json::const_iterator;
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public:
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iterator() = default;
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iterator(json*);
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iterator(const iterator&);
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~iterator();
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iterator& operator=(iterator);
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bool operator==(const iterator&) const;
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bool operator!=(const iterator&) const;
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iterator& operator++();
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json& operator*() const;
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json* operator->() const;
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/// getter for the key (in case of objects)
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std::string key() const;
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/// getter for the value
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json& value() const;
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private:
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/// a JSON value
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json* _object = nullptr;
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/// an iterator for JSON arrays
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array_t::iterator* _vi = nullptr;
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/// an iterator for JSON objects
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object_t::iterator* _oi = nullptr;
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};
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/// a const iterator
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class const_iterator
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{
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friend class json;
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public:
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const_iterator() = default;
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const_iterator(const json*);
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const_iterator(const const_iterator&);
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const_iterator(const iterator&);
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~const_iterator();
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const_iterator& operator=(const_iterator);
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bool operator==(const const_iterator&) const;
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bool operator!=(const const_iterator&) const;
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const_iterator& operator++();
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const json& operator*() const;
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const json* operator->() const;
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/// getter for the key (in case of objects)
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std::string key() const;
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/// getter for the value
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const json& value() const;
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private:
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/// a JSON value
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const json* _object = nullptr;
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/// an iterator for JSON arrays
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array_t::const_iterator* _vi = nullptr;
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/// an iterator for JSON objects
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object_t::const_iterator* _oi = nullptr;
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};
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private:
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/// a helper class to parse a JSON object
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class parser
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{
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public:
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/// a parser reading from a C string
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parser(const char*);
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/// a parser reading from a C++ string
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parser(const std::string&);
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/// a parser reading from an input stream
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parser(std::istream&);
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/// destructor of the parser
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~parser() = default;
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// no copy constructor
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parser(const parser&) = delete;
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// no copy assignment
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parser& operator=(parser) = delete;
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/// parse and return a JSON object
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json parse();
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private:
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/// read the next character, stripping whitespace
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bool next();
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/// raise an exception with an error message
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inline void error(const std::string&) __attribute__((noreturn));
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/// parse a quoted string
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inline std::string parseString();
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/// parse a Boolean "true"
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inline void parseTrue();
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/// parse a Boolean "false"
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inline void parseFalse();
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/// parse a null object
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inline void parseNull();
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/// a helper function to expect a certain character
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inline void expect(const char);
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private:
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/// a buffer of the input
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std::string _buffer {};
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/// the current character
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char _current {};
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/// the position inside the input buffer
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size_t _pos = 0;
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};
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};
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/// user-defined literal operator to create JSON objects from strings
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json operator "" _json(const char*, size_t);
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