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mirror of https://github.com/nlohmann/json synced 2024-12-25 18:11:05 +00:00
nlohmannjson/src/json.hpp.re2c
2015-02-08 14:38:52 +01:00

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#ifndef _NLOHMANN_JSON
#define _NLOHMANN_JSON
#include <algorithm>
#include <cassert>
#include <functional>
#include <initializer_list>
#include <iostream>
#include <iterator>
#include <limits>
#include <map>
#include <memory>
#include <string>
#include <type_traits>
#include <utility>
#include <vector>
/*!
- ObjectType trick from http://stackoverflow.com/a/9860911
*/
/*
template<typename C, typename=void>
struct container_resizable : std::false_type {};
template<typename C>
struct container_resizable<C, decltype(C().resize(0))> : std::true_type {};
*/
/*!
@see https://github.com/nlohmann
*/
namespace nlohmann
{
/*!
@brief JSON
@tparam ObjectType type for JSON objects
(@c std::map by default)
@tparam ArrayType type for JSON arrays
(@c std::vector by default)
@tparam StringType type for JSON strings and object keys
(@c std::string by default)
@tparam BooleanType type for JSON booleans
(@c bool by default)
@tparam NumberIntegerType type for JSON integer numbers
(@c int64_t by default)
@tparam NumberFloatType type for JSON floating-point numbers
(@c double by default)
*/
template <
template<typename U, typename V, typename... Args> class ObjectType = std::map,
//template<typename... Args> class ArrayType = std::vector,
template<typename U, typename... Args> class ArrayType = std::vector,
class StringType = std::string,
class BooleanType = bool,
class NumberIntegerType = int64_t,
class NumberFloatType = double
>
class basic_json
{
public:
/////////////////////
// container types //
/////////////////////
class iterator;
class const_iterator;
/// the type of elements in a basic_json container
using value_type = basic_json;
/// the type of an element reference
using reference = basic_json&;
/// the type of an element const reference
using const_reference = const basic_json&;
/// the type of an element pointer
using pointer = basic_json*;
/// the type of an element const pointer
using const_pointer = const basic_json*;
/// a type to represent differences between iterators
using difference_type = std::ptrdiff_t;
/// a type to represent container sizes
using size_type = std::size_t;
/// an iterator for a basic_json container
using iterator = basic_json::iterator;
/// a const iterator for a basic_json container
using const_iterator = basic_json::const_iterator;
// a reverse iterator for a basic_json container
using reverse_iterator = std::reverse_iterator<iterator>;
/// a const reverse iterator for a basic_json container
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
///////////////////////////
// JSON value data types //
///////////////////////////
/// a type for an object
using object_t = ObjectType<StringType, basic_json>;
/// a type for an array
using array_t = ArrayType<basic_json>;
/// a type for a string
using string_t = StringType;
/// a type for a boolean
using boolean_t = BooleanType;
/// a type for a number (integer)
using number_integer_t = NumberIntegerType;
/// a type for a number (floating-point)
using number_float_t = NumberFloatType;
/// a type for list initialization
using list_init_t = std::initializer_list<basic_json>;
////////////////////////
// JSON value storage //
////////////////////////
/// a JSON value
union json_value
{
/// object (stored with pointer to save storage)
object_t* object;
/// array (stored with pointer to save storage)
array_t* array;
/// string (stored with pointer to save storage)
string_t* string;
/// bolean
boolean_t boolean;
/// number (integer)
number_integer_t number_integer;
/// number (floating-point)
number_float_t number_float;
/// default constructor (for null values)
json_value() = default;
/// constructor for objects
json_value(object_t* v) : object(v) {}
/// constructor for arrays
json_value(array_t* v) : array(v) {}
/// constructor for strings
json_value(string_t* v) : string(v) {}
/// constructor for booleans
json_value(boolean_t v) : boolean(v) {}
/// constructor for numbers (integer)
json_value(number_integer_t v) : number_integer(v) {}
/// constructor for numbers (floating-point)
json_value(number_float_t v) : number_float(v) {}
};
/////////////////////////////////
// JSON value type enumeration //
/////////////////////////////////
/// JSON value type enumeration
enum class value_t : uint8_t
{
/// null value
null,
/// object (unordered set of name/value pairs)
object,
/// array (ordered collection of values)
array,
/// string value
string,
/// boolean value
boolean,
/// number value (integer)
number_integer,
/// number value (floating-point)
number_float
};
//////////////////
// constructors //
//////////////////
/// create an empty value with a given type
inline basic_json(const value_t value)
: m_type(value)
{
switch (m_type)
{
case (value_t::null):
{
break;
}
case (value_t::object):
{
m_value.object = new object_t();
break;
}
case (value_t::array):
{
m_value.array = new array_t();
break;
}
case (value_t::string):
{
m_value.string = new string_t("");
break;
}
case (value_t::boolean):
{
m_value.boolean = boolean_t(false);
break;
}
case (value_t::number_integer):
{
m_value.number_integer = number_integer_t(0);
break;
}
case (value_t::number_float):
{
m_value.number_float = number_float_t(0.0);
break;
}
}
}
/// create a null object (implicitly)
inline basic_json() noexcept
: m_type(value_t::null)
{}
/// create a null object (explicitly)
inline basic_json(std::nullptr_t) noexcept
: m_type(value_t::null)
{}
/// create an object (explicit)
inline basic_json(const object_t& value)
: m_type(value_t::object), m_value(new object_t(value))
{}
/// create an object (implicit)
template <class V, typename
std::enable_if<
std::is_constructible<string_t, typename V::key_type>::value and
std::is_constructible<basic_json, typename V::mapped_type>::value, int>::type
= 0>
inline basic_json(const V& value)
: m_type(value_t::object), m_value(new object_t(value.begin(), value.end()))
{}
/// create an array (explicit)
inline basic_json(const array_t& value)
: m_type(value_t::array), m_value(new array_t(value))
{}
/// create an array (implicit)
template <class V, typename
std::enable_if<
not std::is_same<V, basic_json::iterator>::value and
not std::is_same<V, basic_json::const_iterator>::value and
not std::is_same<V, basic_json::reverse_iterator>::value and
not std::is_same<V, basic_json::const_reverse_iterator>::value and
std::is_constructible<basic_json, typename V::value_type>::value, int>::type
= 0>
inline basic_json(const V& value)
: m_type(value_t::array), m_value(new array_t(value.begin(), value.end()))
{}
/// create a string (explicit)
inline basic_json(const string_t& value)
: m_type(value_t::string), m_value(new string_t(value))
{}
/// create a string (explicit)
inline basic_json(const typename string_t::value_type* value)
: m_type(value_t::string), m_value(new string_t(value))
{}
/// create a string (implicit)
template <class V, typename
std::enable_if<
std::is_constructible<string_t, V>::value, int>::type
= 0>
inline basic_json(const V& value)
: basic_json(string_t(value))
{}
/// create a boolean (explicit)
inline basic_json(boolean_t value)
: m_type(value_t::boolean), m_value(value)
{}
/// create an integer number (explicit)
inline basic_json(const number_integer_t& value)
: m_type(value_t::number_integer), m_value(value)
{}
/// create an integer number (implicit)
template<typename T, typename
std::enable_if<
std::is_constructible<number_integer_t, T>::value and
std::numeric_limits<T>::is_integer, T>::type
= 0>
inline basic_json(const T value) noexcept
: m_type(value_t::number_integer), m_value(number_integer_t(value))
{}
/// create a floating-point number (explicit)
inline basic_json(const number_float_t& value)
: m_type(value_t::number_float), m_value(value)
{}
/// create a floating-point number (implicit)
template<typename T, typename = typename
std::enable_if<
std::is_constructible<number_float_t, T>::value and
std::is_floating_point<T>::value>::type
>
inline basic_json(const T value) noexcept
: m_type(value_t::number_float), m_value(number_float_t(value))
{}
/// create a container (array or object) from an initializer list
inline basic_json(list_init_t l, bool type_deduction = true, value_t manual_type = value_t::array)
{
// the initializer list could describe an object
bool is_object = true;
// check if each element is an array with two elements whose first element
// is a string
for (const auto& element : l)
{
if ((element.m_final and element.m_type == value_t::array)
or (element.m_type != value_t::array or element.size() != 2
or element[0].m_type != value_t::string))
{
// we found an element that makes it impossible to use the
// initializer list as object
is_object = false;
break;
}
}
// adjust type if type deduction is not wanted
if (not type_deduction)
{
// mark this object's type as final
m_final = true;
// if array is wanted, do not create an object though possible
if (manual_type == value_t::array)
{
is_object = false;
}
// if object is wanted but impossible, throw an exception
if (manual_type == value_t::object and not is_object)
{
throw std::logic_error("cannot create JSON object from initializer list");
}
}
if (is_object)
{
// the initializer list is a list of pairs -> create object
m_type = value_t::object;
m_value = new object_t();
for (auto& element : l)
{
m_value.object->emplace(std::move(*(element[0].m_value.string)), std::move(element[1]));
}
}
else
{
// the initializer list describes an array -> create array
m_type = value_t::array;
m_value = new array_t(std::move(l));
}
}
/// explicitly create an array from an initializer list
inline static basic_json array(list_init_t l = list_init_t())
{
return basic_json(l, false, value_t::array);
}
/// explicitly create an object from an initializer list
inline static basic_json object(list_init_t l = list_init_t())
{
return basic_json(l, false, value_t::object);
}
///////////////////////////////////////
// other constructors and destructor //
///////////////////////////////////////
/// copy constructor
inline basic_json(const basic_json& other)
: m_type(other.m_type)
{
switch (m_type)
{
case (value_t::null):
{
break;
}
case (value_t::object):
{
m_value.object = new object_t(*other.m_value.object);
break;
}
case (value_t::array):
{
m_value.array = new array_t(*other.m_value.array);
break;
}
case (value_t::string):
{
m_value.string = new string_t(*other.m_value.string);
break;
}
case (value_t::boolean):
{
m_value.boolean = other.m_value.boolean;
break;
}
case (value_t::number_integer):
{
m_value.number_integer = other.m_value.number_integer;
break;
}
case (value_t::number_float):
{
m_value.number_float = other.m_value.number_float;
break;
}
}
}
/// move constructor
inline basic_json(basic_json&& other) noexcept
: m_type(std::move(other.m_type)),
m_value(std::move(other.m_value))
{
// invalidate payload
other.m_type = value_t::null;
other.m_value = {};
}
/// copy assignment
inline reference operator=(basic_json other) noexcept
{
std::swap(m_type, other.m_type);
std::swap(m_value, other.m_value);
return *this;
}
/// destructor
inline ~basic_json() noexcept
{
switch (m_type)
{
case (value_t::object):
{
delete m_value.object;
m_value.object = nullptr;
break;
}
case (value_t::array):
{
delete m_value.array;
m_value.array = nullptr;
break;
}
case (value_t::string):
{
delete m_value.string;
m_value.string = nullptr;
break;
}
default:
{
// all other types need no specific destructor
break;
}
}
}
public:
///////////////////////
// object inspection //
///////////////////////
/*!
Serialization function for JSON objects. The function tries to mimick Python's
@p json.dumps() function, and currently supports its @p indent parameter.
@param indent if indent is nonnegative, then array elements and object members
will be pretty-printed with that indent level. An indent level
of 0 will only insert newlines. -1 (the default) selects the
most compact representation
@see https://docs.python.org/2/library/json.html#json.dump
*/
inline string_t dump(int indent = -1) const noexcept
{
if (indent >= 0)
{
return dump(true, static_cast<unsigned int>(indent));
}
else
{
return dump(false, 0);
}
}
/// return the type of the object explicitly
inline value_t type() const noexcept
{
return m_type;
}
/// return the type of the object implicitly
operator value_t() const noexcept
{
return m_type;
}
//////////////////////
// value conversion //
//////////////////////
/// get an object
template <class T, typename
std::enable_if<
std::is_constructible<string_t, typename T::key_type>::value and
std::is_constructible<basic_json, typename T::mapped_type>::value, int>::type
= 0>
inline T get() const
{
switch (m_type)
{
case (value_t::object):
return T(m_value.object->begin(), m_value.object->end());
default:
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
/// get an array
template <class T, typename
std::enable_if<
not std::is_same<T, string_t>::value and
std::is_constructible<basic_json, typename T::value_type>::value, int>::type
= 0>
inline T get() const
{
switch (m_type)
{
case (value_t::array):
return T(m_value.array->begin(), m_value.array->end());
default:
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
/// get a string
template <typename T, typename
std::enable_if<
std::is_constructible<T, string_t>::value, int>::type
= 0>
inline T get() const
{
switch (m_type)
{
case (value_t::string):
return *m_value.string;
default:
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
/// get a boolean
template <typename T, typename
std::enable_if<
std::is_same<boolean_t, T>::value, int>::type
= 0>
inline T get() const
{
switch (m_type)
{
case (value_t::boolean):
return m_value.boolean;
default:
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
/// explicitly get a number
template<typename T, typename
std::enable_if<
not std::is_same<boolean_t, T>::value and
std::is_arithmetic<T>::value, int>::type
= 0>
inline T get() const
{
switch (m_type)
{
case (value_t::number_integer):
return static_cast<T>(m_value.number_integer);
case (value_t::number_float):
return static_cast<T>(m_value.number_float);
default:
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
/// explicitly get a value
template<typename T>
inline operator T() const
{
return get<T>();
}
////////////////////
// element access //
////////////////////
/// access specified element with bounds checking
inline reference at(size_type pos)
{
// at only works for arrays
if (m_type != value_t::array)
{
throw std::runtime_error("cannot use at with " + type_name());
}
return m_value.array->at(pos);
}
/// access specified element with bounds checking
inline const_reference at(size_type pos) const
{
// at only works for arrays
if (m_type != value_t::array)
{
throw std::runtime_error("cannot use at with " + type_name());
}
return m_value.array->at(pos);
}
/// access specified element
inline reference operator[](size_type pos)
{
// at only works for arrays
if (m_type != value_t::array)
{
throw std::runtime_error("cannot use [] with " + type_name());
}
return m_value.array->operator[](pos);
}
/// access specified element
inline const_reference operator[](size_type pos) const
{
// at only works for arrays
if (m_type != value_t::array)
{
throw std::runtime_error("cannot use [] with " + type_name());
}
return m_value.array->operator[](pos);
}
/// access specified element with bounds checking
inline reference at(const typename object_t::key_type& key)
{
// at only works for objects
if (m_type != value_t::object)
{
throw std::runtime_error("cannot use at with " + type_name());
}
return m_value.object->at(key);
}
/// access specified element with bounds checking
inline const_reference at(const typename object_t::key_type& key) const
{
// at only works for objects
if (m_type != value_t::object)
{
throw std::runtime_error("cannot use at with " + type_name());
}
return m_value.object->at(key);
}
/// access specified element
inline reference operator[](const typename object_t::key_type& key)
{
// at only works for objects
if (m_type != value_t::object)
{
throw std::runtime_error("cannot use [] with " + type_name());
}
return m_value.object->operator[](key);
}
/// access specified element (needed for clang)
template<typename T, size_t n>
inline reference operator[](const T (&key)[n])
{
// at only works for objects
if (m_type != value_t::object)
{
throw std::runtime_error("cannot use [] with " + type_name());
}
return m_value.object->operator[](key);
}
/// access specified element
inline reference operator[](typename object_t::key_type&& key)
{
// at only works for objects
if (m_type != value_t::object)
{
throw std::runtime_error("cannot use [] with " + type_name());
}
return m_value.object->operator[](std::move(key));
}
/// find an element in an object
inline iterator find(typename object_t::key_type key)
{
auto result = end();
if (m_type == value_t::object)
{
result.m_it.object_iterator = m_value.object->find(key);
}
return result;
}
/// find an element in an object
inline const_iterator find(typename object_t::key_type key) const
{
auto result = cend();
if (m_type == value_t::object)
{
result.m_it.object_iterator = m_value.object->find(key);
}
return result;
}
///////////////
// iterators //
///////////////
/// returns an iterator to the beginning of the container
inline iterator begin() noexcept
{
iterator result(this);
result.set_begin();
return result;
}
/// returns a const iterator to the beginning of the container
inline const_iterator begin() const noexcept
{
const_iterator result(this);
result.set_begin();
return result;
}
/// returns a const iterator to the beginning of the container
inline const_iterator cbegin() const noexcept
{
const_iterator result(this);
result.set_begin();
return result;
}
/// returns an iterator to the end of the container
inline iterator end() noexcept
{
iterator result(this);
result.set_end();
return result;
}
/// returns a const iterator to the end of the container
inline const_iterator end() const noexcept
{
const_iterator result(this);
result.set_end();
return result;
}
/// returns a const iterator to the end of the container
inline const_iterator cend() const noexcept
{
const_iterator result(this);
result.set_end();
return result;
}
/// returns a reverse iterator to the end of the container
inline reverse_iterator rbegin() const noexcept
{
reverse_iterator result(this);
result.set_end();
return result;
}
/// returns a reverse iterator to the beginning of the container
inline reverse_iterator rend() const noexcept
{
reverse_iterator result(this);
result.set_begin();
return result;
}
/// returns a const reverse iterator to the end of the container
inline const_reverse_iterator crbegin() const noexcept
{
const_reverse_iterator result(this);
result.set_end();
return result;
}
/// returns a const reverse iterator to the beginning of the container
inline const_reverse_iterator crend() const noexcept
{
const_reverse_iterator result(this);
result.set_begin();
return result;
}
//////////////
// capacity //
//////////////
/// checks whether the container is empty
inline bool empty() const noexcept
{
switch (m_type)
{
case (value_t::null):
{
return true;
}
case (value_t::array):
{
return m_value.array->empty();
}
case (value_t::object):
{
return m_value.object->empty();
}
default:
{
// all other types are nonempty
return false;
}
}
}
/// returns the number of elements
inline size_type size() const noexcept
{
switch (m_type)
{
case (value_t::null):
{
return 0;
}
case (value_t::array):
{
return m_value.array->size();
}
case (value_t::object):
{
return m_value.object->size();
}
default:
{
// all other types have size 1
return 1;
}
}
}
/// returns the maximum possible number of elements
inline size_type max_size() const noexcept
{
switch (m_type)
{
case (value_t::null):
{
return 0;
}
case (value_t::array):
{
return m_value.array->max_size();
}
case (value_t::object):
{
return m_value.object->max_size();
}
default:
{
// all other types have max_size 1
return 1;
}
}
}
///////////////
// modifiers //
///////////////
/// clears the contents
inline void clear() noexcept
{
switch (m_type)
{
case (value_t::null):
{
break;
}
case (value_t::number_integer):
{
m_value.number_integer = 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;
}
}
}
/// add an object to an array
inline void push_back(basic_json&& value)
{
// push_back only works for null objects or arrays
if (not(m_type == value_t::null or m_type == value_t::array))
{
throw std::runtime_error("cannot add element to " + type_name());
}
// transform null object into an array
if (m_type == value_t::null)
{
m_type = value_t::array;
m_value.array = new array_t;
}
// add element to array (move semantics)
m_value.array->push_back(std::move(value));
// invalidate object
value.m_type = value_t::null;
}
/// add an object to an array
inline void push_back(const basic_json& value)
{
// push_back only works for null objects or arrays
if (not(m_type == value_t::null or m_type == value_t::array))
{
throw std::runtime_error("cannot add element to " + type_name());
}
// transform null object into an array
if (m_type == value_t::null)
{
m_type = value_t::array;
m_value.array = new array_t;
}
// add element to array
m_value.array->push_back(value);
}
/*
/// add an object to an array
inline reference operator+=(const basic_json& value)
{
push_back(value);
return *this;
}
*/
/// add constructible objects to an array
template<class T, typename std::enable_if<std::is_constructible<basic_json, T>::value>::type = 0>
inline void push_back(const T& value)
{
assert(false); // not sure if function will ever be called
push_back(basic_json(value));
}
/*
/// add constructible objects to an array
template<class T, typename std::enable_if<std::is_constructible<basic_json, T>::value>::type = 0>
inline reference operator+=(const T& value)
{
push_back(basic_json(value));
return *this;
}
*/
/// add an object to an object
inline void push_back(const typename object_t::value_type& value)
{
// push_back only works for null objects or objects
if (not(m_type == value_t::null or m_type == value_t::object))
{
throw std::runtime_error("cannot add element to " + type_name());
}
// transform null object into an object
if (m_type == value_t::null)
{
m_type = value_t::object;
m_value.object = new object_t;
}
// add element to array
m_value.object->insert(value);
}
/*
/// add an object to an object
inline reference operator+=(const typename object_t::value_type& value)
{
push_back(value);
return operator[](value.first);
}
*/
/// constructs element in-place at the end of an array
template <typename T, typename
std::enable_if<
std::is_constructible<basic_json, T>::value, int>::type
= 0>
inline void emplace_back(T && arg)
{
// push_back only works for null objects or arrays
if (not(m_type == value_t::null or m_type == value_t::array))
{
throw std::runtime_error("cannot add element to " + type_name());
}
// transform null object into an array
if (m_type == value_t::null)
{
m_type = value_t::array;
m_value.array = new array_t;
}
// add element to array
m_value.array->emplace_back(std::forward<T>(arg));
}
/// swaps the contents
inline void swap(reference other) noexcept
{
std::swap(m_type, other.m_type);
std::swap(m_value, other.m_value);
}
/// swaps the contents
inline void swap(array_t& other)
{
// swap only works for arrays
if (m_type != value_t::array)
{
throw std::runtime_error("cannot use swap with " + type_name());
}
// swap arrays
std::swap(*(m_value.array), other);
}
/// swaps the contents
inline void swap(object_t& other)
{
// swap only works for objects
if (m_type != value_t::object)
{
throw std::runtime_error("cannot use swap with " + type_name());
}
// swap arrays
std::swap(*(m_value.object), other);
}
/// swaps the contents
inline void swap(string_t& other)
{
// swap only works for strings
if (m_type != value_t::string)
{
throw std::runtime_error("cannot use swap with " + type_name());
}
// swap arrays
std::swap(*(m_value.string), other);
}
//////////////////////////////////////////
// lexicographical comparison operators //
//////////////////////////////////////////
/// comparison: equal
friend bool operator==(const_reference lhs, const_reference rhs)
{
switch (lhs.type())
{
case (value_t::array):
{
if (rhs.type() == value_t::array)
{
return *lhs.m_value.array == *rhs.m_value.array;
}
break;
}
case (value_t::object):
{
if (rhs.type() == value_t::object)
{
return *lhs.m_value.object == *rhs.m_value.object;
}
break;
}
case (value_t::null):
{
if (rhs.type() == value_t::null)
{
return true;
}
break;
}
case (value_t::string):
{
if (rhs.type() == value_t::string)
{
return *lhs.m_value.string == *rhs.m_value.string;
}
break;
}
case (value_t::boolean):
{
if (rhs.type() == value_t::boolean)
{
return lhs.m_value.boolean == rhs.m_value.boolean;
}
break;
}
case (value_t::number_integer):
{
if (rhs.type() == value_t::number_integer)
{
return lhs.m_value.number_integer == rhs.m_value.number_integer;
}
if (rhs.type() == value_t::number_float)
{
return lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_float);
}
break;
}
case (value_t::number_float):
{
if (rhs.type() == value_t::number_integer)
{
return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer);
}
if (rhs.type() == value_t::number_float)
{
return lhs.m_value.number_float == rhs.m_value.number_float;
}
break;
}
}
return false;
}
/// comparison: not equal
friend bool operator!=(const_reference lhs, const_reference rhs)
{
return not (lhs == rhs);
}
/// comparison: less than
friend bool operator<(const_reference lhs, const_reference rhs)
{
switch (lhs.type())
{
case (value_t::array):
{
if (rhs.type() == value_t::array)
{
return *lhs.m_value.array < *rhs.m_value.array;
}
break;
}
case (value_t::object):
{
if (rhs.type() == value_t::object)
{
return *lhs.m_value.object < *rhs.m_value.object;
}
break;
}
case (value_t::null):
{
if (rhs.type() == value_t::null)
{
return false;
}
break;
}
case (value_t::string):
{
if (rhs.type() == value_t::string)
{
return *lhs.m_value.string < *rhs.m_value.string;
}
break;
}
case (value_t::boolean):
{
if (rhs.type() == value_t::boolean)
{
return lhs.m_value.boolean < rhs.m_value.boolean;
}
break;
}
case (value_t::number_integer):
{
if (rhs.type() == value_t::number_integer)
{
return lhs.m_value.number_integer < rhs.m_value.number_integer;
}
if (rhs.type() == value_t::number_float)
{
return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_float);
}
break;
}
case (value_t::number_float):
{
if (rhs.type() == value_t::number_integer)
{
return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
}
if (rhs.type() == value_t::number_float)
{
return lhs.m_value.number_float < rhs.m_value.number_float;
}
break;
}
}
return false;
}
/// comparison: less than or equal
friend bool operator<=(const_reference lhs, const_reference rhs)
{
return not (rhs < lhs);
}
/// comparison: greater than
friend bool operator>(const_reference lhs, const_reference rhs)
{
return not (lhs <= rhs);
}
/// comparison: greater than or equal
friend bool operator>=(const_reference lhs, const_reference rhs)
{
return not (lhs < rhs);
}
///////////////////
// serialization //
///////////////////
/// serialize to stream
friend std::ostream& operator<<(std::ostream& o, const basic_json& j)
{
o << j.dump();
return o;
}
/// serialize to stream
friend std::ostream& operator>>(const basic_json& j, std::ostream& o)
{
o << j.dump();
return o;
}
/////////////////////
// deserialization //
/////////////////////
/// deserialize from string
static basic_json parse(const std::string& s)
{
return parser(s).parse();
}
/// deserialize from stream
friend std::istream& operator>>(std::istream& i, basic_json& j)
{
j = parser(i).parse();
return i;
}
/// deserialize from stream
friend std::istream& operator<<(basic_json& j, std::istream& i)
{
j = parser(i).parse();
return i;
}
private:
///////////////////////////
// convenience functions //
///////////////////////////
/// return the type as string
inline string_t 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::number_integer):
case (value_t::number_float):
{
return "number";
}
}
}
/*!
@brief escape a string
Escape a string by replacing certain special characters by a sequence of an
escape character (backslash) and another character and other control
characters by a sequence of "\u" followed by a four-digit hex
representation.
@param s the string to escape
@return escaped string
*/
static string_t escape_string(const string_t& s) noexcept
{
// create a result string of at least the size than s
string_t result;
result.reserve(s.size());
for (const auto c : s)
{
switch (c)
{
// quotation mark (0x22)
case '"':
{
result += "\\\"";
break;
}
// reverse solidus (0x5c)
case '\\':
{
result += "\\\\";
break;
}
// backspace (0x08)
case '\b':
{
result += "\\b";
break;
}
// formfeed (0x0c)
case '\f':
{
result += "\\f";
break;
}
// newline (0x0a)
case '\n':
{
result += "\\n";
break;
}
// carriage return (0x0d)
case '\r':
{
result += "\\r";
break;
}
// horizontal tab (0x09)
case '\t':
{
result += "\\t";
break;
}
default:
{
if (c <= 0x1f)
{
// control characters (everything between 0x00 and 0x1f)
// -> create four-digit hex representation
std::stringstream ss;
ss << "\\u" << std::hex << std::setw(4) << std::setfill('0') << int(c);
result += ss.str();
}
else
{
// all other characters are added as-is
result.append(1, c);
}
break;
}
}
}
return result;
}
/*!
@brief internal implementation of the serialization function
This function is called by the public member function dump and organizes
the serializaion internally. The indentation level is propagated as
additional parameter. In case of arrays and objects, the function is called
recursively. Note that
- strings and object keys are escaped using escape_string()
- numbers are converted to a string before output using std::to_string()
@param prettyPrint whether the output shall be pretty-printed
@param indentStep the indent level
@param currentIndent the current indent level (only used internally)
*/
inline string_t dump(const bool prettyPrint, const unsigned int indentStep,
unsigned int currentIndent = 0) const noexcept
{
// helper function to return whitespace as indentation
const auto indent = [prettyPrint, &currentIndent]()
{
return prettyPrint ? string_t(currentIndent, ' ') : string_t();
};
switch (m_type)
{
case (value_t::null):
{
return "null";
}
case (value_t::object):
{
if (m_value.object->empty())
{
return "{}";
}
string_t result = "{";
// increase indentation
if (prettyPrint)
{
currentIndent += indentStep;
result += "\n";
}
for (auto i = m_value.object->cbegin(); i != m_value.object->cend(); ++i)
{
if (i != m_value.object->cbegin())
{
result += prettyPrint ? ",\n" : ",";
}
result += indent() + "\"" + escape_string(i->first) + "\":" + (prettyPrint ? " " : "")
+ i->second.dump(prettyPrint, indentStep, currentIndent);
}
// decrease indentation
if (prettyPrint)
{
currentIndent -= indentStep;
result += "\n";
}
return result + indent() + "}";
}
case (value_t::array):
{
if (m_value.array->empty())
{
return "[]";
}
string_t result = "[";
// increase indentation
if (prettyPrint)
{
currentIndent += indentStep;
result += "\n";
}
for (auto i = m_value.array->cbegin(); i != m_value.array->cend(); ++i)
{
if (i != m_value.array->cbegin())
{
result += prettyPrint ? ",\n" : ",";
}
result += indent() + i->dump(prettyPrint, indentStep, currentIndent);
}
// decrease indentation
if (prettyPrint)
{
currentIndent -= indentStep;
result += "\n";
}
return result + indent() + "]";
}
case (value_t::string):
{
return string_t("\"") + escape_string(*m_value.string) + "\"";
}
case (value_t::boolean):
{
return m_value.boolean ? "true" : "false";
}
case (value_t::number_integer):
{
return std::to_string(m_value.number_integer);
}
case (value_t::number_float):
{
return std::to_string(m_value.number_float);
}
}
}
private:
//////////////////////
// member variables //
//////////////////////
/// the type of the current element
value_t m_type = value_t::null;
/// whether the type of JSON object may change later
bool m_final = false;
/// the value of the current element
json_value m_value = {};
public:
///////////////
// iterators //
///////////////
/// a bidirectional iterator for the basic_json class
class iterator : public std::iterator<std::bidirectional_iterator_tag, basic_json>
{
public:
/// the type of the values when the iterator is dereferenced
using value_type = basic_json::value_type;
/// a type to represent differences between iterators
using difference_type = basic_json::difference_type;
/// defines a pointer to the type iterated over (value_type)
using pointer = basic_json::pointer;
/// defines a reference to the type iterated over (value_type)
using reference = basic_json::reference;
/// the category of the iterator
using iterator_category = std::bidirectional_iterator_tag;
/// values of a generic iterator type of non-container JSON values
enum class generic_iterator_value
{
/// the iterator was not initialized
uninitialized,
/// the iterator points to the only value
begin,
/// the iterator points past the only value
end,
/// the iterator points to an invalid value
invalid
};
/// an iterator value
union internal_iterator
{
/// iterator for JSON objects
typename object_t::iterator object_iterator;
/// iterator for JSON arrays
typename array_t::iterator array_iterator;
/// generic iteraotr for all other value types
generic_iterator_value generic_iterator;
/// default constructor
internal_iterator() : generic_iterator(generic_iterator_value::uninitialized) {}
/// constructor for object iterators
internal_iterator(typename object_t::iterator v) : object_iterator(v) {}
/// constructor for array iterators
internal_iterator(typename array_t::iterator v) : array_iterator(v) {}
/// constructor for generic iterators
internal_iterator(generic_iterator_value v) : generic_iterator(v) {}
};
/// constructor for a given JSON instance
inline iterator(pointer object) : m_object(object)
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
m_it.object_iterator = typename object_t::iterator();
break;
}
case (basic_json::value_t::array):
{
m_it.array_iterator = typename array_t::iterator();
break;
}
default:
{
m_it.generic_iterator = generic_iterator_value::uninitialized;
break;
}
}
}
/// copy assignment
inline iterator& operator=(const iterator& other) noexcept
{
m_object = other.m_object;
m_it = other.m_it;
return *this;
}
/// set the iterator to the first value
inline void set_begin() noexcept
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
m_it.object_iterator = m_object->m_value.object->begin();
break;
}
case (basic_json::value_t::array):
{
m_it.array_iterator = m_object->m_value.array->begin();
break;
}
case (basic_json::value_t::null):
{
// set to end so begin()==end() is true: null is empty
m_it.generic_iterator = generic_iterator_value::end;
break;
}
default:
{
m_it.generic_iterator = generic_iterator_value::begin;
break;
}
}
}
/// set the iterator past the last value
inline void set_end() noexcept
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
m_it.object_iterator = m_object->m_value.object->end();
break;
}
case (basic_json::value_t::array):
{
m_it.array_iterator = m_object->m_value.array->end();
break;
}
default:
{
m_it.generic_iterator = generic_iterator_value::end;
break;
}
}
}
/// return a reference to the value pointed to by the iterator
inline reference operator*() const
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
return m_it.object_iterator->second;
}
case (basic_json::value_t::array):
{
return *m_it.array_iterator;
}
case (basic_json::value_t::null):
{
throw std::out_of_range("cannot get value");
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::begin)
{
return *m_object;
}
else
{
throw std::out_of_range("cannot get value");
}
}
}
}
/// dereference the iterator
inline pointer operator->() const
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
return &(m_it.object_iterator->second);
}
case (basic_json::value_t::array):
{
return &*m_it.array_iterator;
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::begin)
{
return m_object;
}
else
{
throw std::out_of_range("cannot get value");
}
}
}
}
/// post-increment (it++)
inline iterator operator++(int)
{
iterator result = *this;
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
m_it.object_iterator++;
break;
}
case (basic_json::value_t::array):
{
m_it.array_iterator++;
break;
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::begin)
{
m_it.generic_iterator = generic_iterator_value::end;
}
else
{
m_it.generic_iterator = generic_iterator_value::invalid;
}
break;
}
}
return result;
}
/// pre-increment (++it)
inline iterator& operator++()
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
++m_it.object_iterator;
break;
}
case (basic_json::value_t::array):
{
++m_it.array_iterator;
break;
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::begin)
{
m_it.generic_iterator = generic_iterator_value::end;
}
else
{
m_it.generic_iterator = generic_iterator_value::invalid;
}
break;
}
}
return *this;
}
/// post-decrement (it--)
inline iterator operator--(int)
{
iterator result = *this;
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
m_it.object_iterator--;
break;
}
case (basic_json::value_t::array):
{
m_it.array_iterator--;
break;
}
case (basic_json::value_t::null):
{
m_it.generic_iterator = generic_iterator_value::invalid;
break;
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::end)
{
m_it.generic_iterator = generic_iterator_value::begin;
}
else
{
m_it.generic_iterator = generic_iterator_value::invalid;
}
break;
}
}
return result;
}
/// pre-decrement (--it)
inline iterator& operator--()
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
--m_it.object_iterator;
break;
}
case (basic_json::value_t::array):
{
--m_it.array_iterator;
break;
}
case (basic_json::value_t::null):
{
m_it.generic_iterator = generic_iterator_value::invalid;
break;
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::end)
{
m_it.generic_iterator = generic_iterator_value::begin;
}
else
{
m_it.generic_iterator = generic_iterator_value::invalid;
}
break;
}
}
return *this;
}
/// comparison: equal
inline bool operator==(const iterator& other) const
{
if (m_object != other.m_object or m_object->m_type != other.m_object->m_type)
{
return false;
}
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
return (m_it.object_iterator == other.m_it.object_iterator);
}
case (basic_json::value_t::array):
{
return (m_it.array_iterator == other.m_it.array_iterator);
}
default:
{
return (m_it.generic_iterator == other.m_it.generic_iterator);
}
}
}
/// comparison: not equal
inline bool operator!=(const iterator& other) const
{
return not operator==(other);
}
private:
/// associated JSON instance
pointer m_object = nullptr;
/// the actual iterator of the associated instance
internal_iterator m_it;
};
/// a const bidirectional iterator for the basic_json class
class const_iterator : public std::iterator<std::bidirectional_iterator_tag, const basic_json>
{
public:
/// the type of the values when the iterator is dereferenced
using value_type = basic_json::value_type;
/// a type to represent differences between iterators
using difference_type = basic_json::difference_type;
/// defines a pointer to the type iterated over (value_type)
using pointer = basic_json::const_pointer;
/// defines a reference to the type iterated over (value_type)
using reference = basic_json::const_reference;
/// the category of the iterator
using iterator_category = std::bidirectional_iterator_tag;
/// values of a generic iterator type of non-container JSON values
enum class generic_iterator_value
{
/// the iterator was not initialized
uninitialized,
/// the iterator points to the only value
begin,
/// the iterator points past the only value
end,
/// the iterator points to an invalid value
invalid
};
/// an iterator value
union internal_const_iterator
{
/// iterator for JSON objects
typename object_t::const_iterator object_iterator;
/// iterator for JSON arrays
typename array_t::const_iterator array_iterator;
/// generic iteraotr for all other value types
generic_iterator_value generic_iterator;
/// default constructor
internal_const_iterator() : generic_iterator(generic_iterator_value::uninitialized) {}
/// constructor for object iterators
internal_const_iterator(typename object_t::iterator v) : object_iterator(v) {}
/// constructor for array iterators
internal_const_iterator(typename array_t::iterator v) : array_iterator(v) {}
/// constructor for generic iterators
internal_const_iterator(generic_iterator_value v) : generic_iterator(v) {}
};
/// constructor for a given JSON instance
inline const_iterator(pointer object) : m_object(object)
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
m_it.object_iterator = typename object_t::const_iterator();
break;
}
case (basic_json::value_t::array):
{
m_it.array_iterator = typename array_t::const_iterator();
break;
}
default:
{
m_it.generic_iterator = generic_iterator_value::uninitialized;
break;
}
}
}
/// copy constructor given a nonconst iterator
inline const_iterator(const iterator& other) : m_object(other.m_object), m_it(other.m_it)
{}
/// copy assignment
inline const_iterator operator=(const const_iterator& other) noexcept
{
m_object = other.m_object;
m_it = other.m_it;
return *this;
}
/// set the iterator to the first value
inline void set_begin() noexcept
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
m_it.object_iterator = m_object->m_value.object->cbegin();
break;
}
case (basic_json::value_t::array):
{
m_it.array_iterator = m_object->m_value.array->cbegin();
break;
}
case (basic_json::value_t::null):
{
// set to end so begin()==end() is true: null is empty
m_it.generic_iterator = generic_iterator_value::end;
break;
}
default:
{
m_it.generic_iterator = generic_iterator_value::begin;
break;
}
}
}
/// set the iterator past the last value
inline void set_end() noexcept
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
m_it.object_iterator = m_object->m_value.object->cend();
break;
}
case (basic_json::value_t::array):
{
m_it.array_iterator = m_object->m_value.array->cend();
break;
}
default:
{
m_it.generic_iterator = generic_iterator_value::end;
break;
}
}
}
/// return a reference to the value pointed to by the iterator
inline reference operator*() const
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
return m_it.object_iterator->second;
}
case (basic_json::value_t::array):
{
return *m_it.array_iterator;
}
case (basic_json::value_t::null):
{
throw std::out_of_range("cannot get value");
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::begin)
{
return *m_object;
}
else
{
throw std::out_of_range("cannot get value");
}
}
}
}
/// dereference the iterator
inline pointer operator->() const
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
return &(m_it.object_iterator->second);
}
case (basic_json::value_t::array):
{
return &*m_it.array_iterator;
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::begin)
{
return m_object;
}
else
{
throw std::out_of_range("cannot get value");
}
}
}
}
/// post-increment (it++)
inline const_iterator operator++(int)
{
const_iterator result = *this;
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
m_it.object_iterator++;
break;
}
case (basic_json::value_t::array):
{
m_it.array_iterator++;
break;
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::begin)
{
m_it.generic_iterator = generic_iterator_value::end;
}
else
{
m_it.generic_iterator = generic_iterator_value::invalid;
}
break;
}
}
return result;
}
/// pre-increment (++it)
inline const_iterator& operator++()
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
++m_it.object_iterator;
break;
}
case (basic_json::value_t::array):
{
++m_it.array_iterator;
break;
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::begin)
{
m_it.generic_iterator = generic_iterator_value::end;
}
else
{
m_it.generic_iterator = generic_iterator_value::invalid;
}
break;
}
}
return *this;
}
/// post-decrement (it--)
inline const_iterator operator--(int)
{
iterator result = *this;
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
m_it.object_iterator--;
break;
}
case (basic_json::value_t::array):
{
m_it.array_iterator--;
break;
}
case (basic_json::value_t::null):
{
m_it.generic_iterator = generic_iterator_value::invalid;
break;
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::end)
{
m_it.generic_iterator = generic_iterator_value::begin;
}
else
{
m_it.generic_iterator = generic_iterator_value::invalid;
}
break;
}
}
return result;
}
/// pre-decrement (--it)
inline const_iterator& operator--()
{
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
--m_it.object_iterator;
break;
}
case (basic_json::value_t::array):
{
--m_it.array_iterator;
break;
}
case (basic_json::value_t::null):
{
m_it.generic_iterator = generic_iterator_value::invalid;
break;
}
default:
{
if (m_it.generic_iterator == generic_iterator_value::end)
{
m_it.generic_iterator = generic_iterator_value::begin;
}
else
{
m_it.generic_iterator = generic_iterator_value::invalid;
}
break;
}
}
return *this;
}
/// comparison: equal
inline bool operator==(const const_iterator& other) const
{
if (m_object != other.m_object or m_object->m_type != other.m_object->m_type)
{
return false;
}
switch (m_object->m_type)
{
case (basic_json::value_t::object):
{
return (m_it.object_iterator == other.m_it.object_iterator);
}
case (basic_json::value_t::array):
{
return (m_it.array_iterator == other.m_it.array_iterator);
}
default:
{
return (m_it.generic_iterator == other.m_it.generic_iterator);
}
}
}
/// comparison: not equal
inline bool operator!=(const const_iterator& other) const
{
return not operator==(other);
}
private:
/// associated JSON instance
pointer m_object = nullptr;
/// the actual iterator of the associated instance
internal_const_iterator m_it;
};
private:
////////////
// parser //
////////////
class parser
{
private:
/// token types for the parser
enum class token_type
{
uninitialized,
literal_true,
literal_false,
literal_null,
value_string,
value_number,
begin_array,
begin_object,
end_array,
end_object,
name_separator,
value_separator,
parse_error
};
/// the type of a lexer character
using lexer_char_t = unsigned char;
public:
/// constructor for strings
inline parser(const std::string& s) : buffer(s)
{
// set buffer for RE2C
buffer_re2c = reinterpret_cast<const lexer_char_t*>(buffer.c_str());
// set a pointer past the end of the buffer
buffer_re2c_limit = buffer_re2c + buffer.size();
// read first token
get_token();
}
/// a parser reading from an input stream
inline parser(std::istream& _is)
{
while (_is)
{
std::string input_line;
std::getline(_is, input_line);
buffer += input_line;
}
// set buffer for RE2C
buffer_re2c = reinterpret_cast<const lexer_char_t*>(buffer.c_str());
// set a pointer past the end of the buffer
buffer_re2c_limit = buffer_re2c + buffer.size();
// read first token
get_token();
}
inline basic_json parse()
{
switch (last_token)
{
case (token_type::begin_object):
{
// explicitly set result to object to cope with {}
basic_json result(value_t::object);
// read next token
get_token();
// closing } -> we are done
if (last_token == token_type::end_object)
{
return result;
}
// otherwise: parse key-value pairs
do
{
// store key
expect_new(token_type::value_string);
const auto key = get_string();
// parse separator (:)
get_token();
expect_new(token_type::name_separator);
// parse value
get_token();
result[key] = parse();
// read next character
get_token();
}
while (last_token == token_type::value_separator
and get_token() == last_token);
// closing }
expect_new(token_type::end_object);
return result;
}
case (token_type::begin_array):
{
// explicitly set result to object to cope with []
basic_json result(value_t::array);
// read next token
get_token();
// closing ] -> we are done
if (last_token == token_type::end_array)
{
return result;
}
// otherwise: parse values
do
{
// parse value
result.push_back(parse());
// read next character
get_token();
}
while (last_token == token_type::value_separator
and get_token() == last_token);
// closing ]
expect_new(token_type::end_array);
return result;
}
case (token_type::literal_null):
{
return basic_json(nullptr);
}
case (token_type::value_string):
{
return basic_json(get_string());
}
case (token_type::literal_true):
{
return basic_json(true);
}
case (token_type::literal_false):
{
return basic_json(false);
}
case (token_type::value_number):
{
// The pointer current_re2c points to the beginning of the
// parsed number. We pass this pointer to std::strtod which
// sets endptr to the first character past the converted
// number. If this pointer is not the same as buffer_re2c,
// then either more or less characters have been used
// during the comparison. This can happen for inputs like
// "01" which will be treated like number 0 followed by
// number 1.
// conversion
char* endptr;
const auto float_val = std::strtod(reinterpret_cast<const char*>(current_re2c), &endptr);
// check if strtod read beyond the end of the lexem
if (reinterpret_cast<const lexer_char_t*>(endptr) != buffer_re2c)
{
throw std::invalid_argument(std::string("parse error - ") +
reinterpret_cast<const char*>(current_re2c) + " is not a number");
}
// check if conversion loses precision
const auto int_val = static_cast<int>(float_val);
if (float_val == int_val)
{
// we basic_json not lose precision -> return int
return basic_json(int_val);
}
else
{
// we would lose precision -> returnfloat
return basic_json(float_val);
}
}
default:
{
std::string error_msg = "parse error - unexpected \'";
error_msg += static_cast<char>(current_re2c[0]);
error_msg += "\' (";
error_msg += token_type_name(last_token) + ")";
throw std::invalid_argument(error_msg);
}
}
}
private:
/*!
This function implements a scanner for JSON. It is specified using
regular expressions that try to follow RFC 7159 and ECMA-404 as close
as possible. These regular expressions are then translated into a
deterministic finite automaton (DFA) by the tool RE2C. As a result, the
translated code for this function consists of a large block of code
with goto jumps.
@return the class of the next token read from the buffer
@todo Unicode support needs to be checked.
*/
inline token_type get_token()
{
// needed by RE2C
const lexer_char_t* marker;
// set up RE2C
/*!re2c
re2c:labelprefix = "json_parser_";
re2c:yyfill:enable = 0;
re2c:define:YYCURSOR = buffer_re2c;
re2c:define:YYCTYPE = lexer_char_t;
re2c:define:YYMARKER = marker;
re2c:indent:string = " ";
re2c:define:YYLIMIT = buffer_re2c_limit;
*/
for (;;)
{
// set current to the begin of the buffer
current_re2c = buffer_re2c;
/*!re2c
// whitespace
ws = [ \t\n\r]*;
ws { continue; }
// structural characters
"[" { return last_token = token_type::begin_array; }
"]" { return last_token = token_type::end_array; }
"{" { return last_token = token_type::begin_object; }
"}" { return last_token = token_type::end_object; }
"," { return last_token = token_type::value_separator; }
":" { return last_token = token_type::name_separator; }
// literal names
"null" { return last_token = token_type::literal_null; }
"true" { return last_token = token_type::literal_true; }
"false" { return last_token = token_type::literal_false; }
// number
decimal_point = [.];
digit = [0-9];
digit_1_9 = [1-9];
e = [eE];
minus = [-];
plus = [+];
zero = [0];
exp = e (minus|plus)? digit+;
frac = decimal_point digit+;
int = (zero|digit_1_9 digit*);
number = minus? int frac? exp?;
number { return last_token = token_type::value_number; }
// string
quotation_mark = [\"];
escape = [\\];
unescaped = [^\"\\];
escaped = escape ([\"\\/bfnrt] | [u][0-9a-fA-F]{4});
char = unescaped | escaped;
string = quotation_mark char* quotation_mark;
string { return last_token = token_type::value_string; }
// anything else is an error
* { return last_token = token_type::parse_error; }
*/
}
}
inline std::string token_type_name(token_type t)
{
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 (token_type::value_number):
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>";
}
}
inline void expect_new(token_type t)
{
if (t != last_token)
{
std::string error_msg = "parse error - unexpected \'";
error_msg += static_cast<char>(current_re2c[0]);
error_msg += "\' (" + token_type_name(last_token);
error_msg += "); expected " + token_type_name(t);
throw std::invalid_argument(error_msg);
}
}
/*!
The pointer current_re2c points to the opening quote of the string, and
buffer_re2c past the closing quote of the string. We create a std::string from
the character after the opening quotes (current_re2c+1) until the character
before the closing quotes (hence subtracting 2 characters from the pointer
difference of the two pointers).
@return string value of current token without opening and closing quotes
@todo Take care of Unicode.
*/
inline std::string get_string() const
{
return std::string(
reinterpret_cast<const char*>(current_re2c + 1),
static_cast<std::size_t>(buffer_re2c - current_re2c - 2)
);
}
private:
/// the buffer
std::string buffer;
/// a pointer to the next character to read from the buffer
const lexer_char_t* buffer_re2c = nullptr;
/// a pointer past the last character of the buffer
const lexer_char_t* buffer_re2c_limit = nullptr;
/// a pointer to the beginning of the current token
const lexer_char_t* current_re2c = nullptr;
/// the type of the last read token
token_type last_token = token_type::uninitialized;
};
};
/////////////
// presets //
/////////////
/// default JSON class
using json = basic_json<>;
}
/////////////////////////
// nonmember functions //
/////////////////////////
// specialization of std::swap, and std::hash
namespace std
{
/// swaps the values of two JSON objects
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);
}
/// hash value for JSON objects
template <>
struct hash<nlohmann::json>
{
/// return a hash value for a JSON object
inline size_t operator()(const nlohmann::json& j) const
{
// a naive hashing via the string representation
return hash<std::string>()(j.dump());
}
};
}
/*!
This operator implements a user-defined string literal for JSON objects. It can
be used by adding \p "_json" to a string literal and returns a JSON object if
no parse error occurred.
@param s a string representation of a JSON object
@return a JSON object
*/
inline nlohmann::json operator "" _json(const char* s, std::size_t)
{
return nlohmann::json::parse(s);
}
#endif