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json.hpp
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json.hpp
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/*
__ _____ _____ _____
__| | __| | | | JSON for Modern C++
| | |__ | | | | | | version 2.0.10
|_____|_____|_____|_|___| https://github.com/nlohmann/json
Licensed under the MIT License <http://opensource.org/licenses/MIT>.
Copyright (c) 2013-2017 Niels Lohmann <http://nlohmann.me>.
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
#ifndef NLOHMANN_JSON_HPP
#define NLOHMANN_JSON_HPP
#include <algorithm> // all_of, for_each, transform
#include <array> // array
#include <cassert> // assert
#include <cctype> // isdigit
#include <ciso646> // and, not, or
#include <cmath> // isfinite, ldexp, signbit
#include <cstddef> // nullptr_t, ptrdiff_t, size_t
#include <cstdint> // int64_t, uint64_t
#include <cstdlib> // strtod, strtof, strtold, strtoul
#include <cstring> // strlen
#include <forward_list> // forward_list
#include <functional> // function, hash, less
#include <initializer_list> // initializer_list
#include <iomanip> // setw
#include <iostream> // istream, ostream
#include <iterator> // advance, begin, bidirectional_iterator_tag, distance, end, inserter, iterator, iterator_traits, next, random_access_iterator_tag, reverse_iterator
#include <limits> // numeric_limits
#include <locale> // locale
#include <map> // map
#include <memory> // addressof, allocator, allocator_traits, unique_ptr
#include <numeric> // accumulate
#include <sstream> // stringstream
#include <stdexcept> // domain_error, invalid_argument, out_of_range
#include <string> // getline, stoi, string, to_string
#include <type_traits> // add_pointer, enable_if, is_arithmetic, is_base_of, is_const, is_constructible, is_convertible, is_floating_point, is_integral, is_nothrow_move_assignable, std::is_nothrow_move_constructible, std::is_pointer, std::is_reference, std::is_same, remove_const, remove_pointer, remove_reference
#include <utility> // declval, forward, make_pair, move, pair, swap
#include <vector> // vector
// exclude unsupported compilers
#if defined(__clang__)
#if (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__) < 30400
#error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
#endif
#elif defined(__GNUC__)
#if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40900
#error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
#endif
#endif
// disable float-equal warnings on GCC/clang
#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wfloat-equal"
#endif
// disable documentation warnings on clang
#if defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdocumentation"
#endif
// allow for portable deprecation warnings
#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
#define JSON_DEPRECATED __attribute__((deprecated))
#elif defined(_MSC_VER)
#define JSON_DEPRECATED __declspec(deprecated)
#else
#define JSON_DEPRECATED
#endif
// allow to disable exceptions
#if not defined(JSON_NOEXCEPTION) || defined(__EXCEPTIONS)
#define JSON_THROW(exception) throw exception
#define JSON_TRY try
#define JSON_CATCH(exception) catch(exception)
#else
#define JSON_THROW(exception) std::abort()
#define JSON_TRY if(true)
#define JSON_CATCH(exception) if(false)
#endif
/*!
@brief namespace for Niels Lohmann
@see https://github.com/nlohmann
@since version 1.0.0
*/
namespace nlohmann
{
/*!
@brief unnamed namespace with internal helper functions
This namespace collects some functions that could not be defined inside the
@ref basic_json class.
@since version 2.1.0
*/
namespace detail
{
///////////////////////////
// JSON type enumeration //
///////////////////////////
/*!
@brief the JSON type enumeration
This enumeration collects the different JSON types. It is internally used to
distinguish the stored values, and the functions @ref basic_json::is_null(),
@ref basic_json::is_object(), @ref basic_json::is_array(),
@ref basic_json::is_string(), @ref basic_json::is_boolean(),
@ref basic_json::is_number() (with @ref basic_json::is_number_integer(),
@ref basic_json::is_number_unsigned(), and @ref basic_json::is_number_float()),
@ref basic_json::is_discarded(), @ref basic_json::is_primitive(), and
@ref basic_json::is_structured() rely on it.
@note There are three enumeration entries (number_integer, number_unsigned, and
number_float), because the library distinguishes these three types for numbers:
@ref basic_json::number_unsigned_t is used for unsigned integers,
@ref basic_json::number_integer_t is used for signed integers, and
@ref basic_json::number_float_t is used for floating-point numbers or to
approximate integers which do not fit in the limits of their respective type.
@sa @ref basic_json::basic_json(const value_t value_type) -- create a JSON
value with the default value for a given type
@since version 1.0.0
*/
enum class value_t : uint8_t
{
null, ///< null value
object, ///< object (unordered set of name/value pairs)
array, ///< array (ordered collection of values)
string, ///< string value
boolean, ///< boolean value
number_integer, ///< number value (signed integer)
number_unsigned, ///< number value (unsigned integer)
number_float, ///< number value (floating-point)
discarded ///< discarded by the the parser callback function
};
/*!
@brief comparison operator for JSON types
Returns an ordering that is similar to Python:
- order: null < boolean < number < object < array < string
- furthermore, each type is not smaller than itself
@since version 1.0.0
*/
inline bool operator<(const value_t lhs, const value_t rhs) noexcept
{
static constexpr std::array<uint8_t, 8> order = {{
0, // null
3, // object
4, // array
5, // string
1, // boolean
2, // integer
2, // unsigned
2, // float
}
};
// discarded values are not comparable
if (lhs == value_t::discarded or rhs == value_t::discarded)
{
return false;
}
return order[static_cast<std::size_t>(lhs)] <
order[static_cast<std::size_t>(rhs)];
}
/////////////
// helpers //
/////////////
// alias templates to reduce boilerplate
template<bool B, typename T = void>
using enable_if_t = typename std::enable_if<B, T>::type;
template<typename T>
using uncvref_t = typename std::remove_cv<typename std::remove_reference<T>::type>::type;
// taken from http://stackoverflow.com/a/26936864/266378
template<typename T>
using is_unscoped_enum =
std::integral_constant<bool, std::is_convertible<T, int>::value and
std::is_enum<T>::value>;
/*
Implementation of two C++17 constructs: conjunction, negation. This is needed
to avoid evaluating all the traits in a condition
For example: not std::is_same<void, T>::value and has_value_type<T>::value
will not compile when T = void (on MSVC at least). Whereas
conjunction<negation<std::is_same<void, T>>, has_value_type<T>>::value will
stop evaluating if negation<...>::value == false
Please note that those constructs must be used with caution, since symbols can
become very long quickly (which can slow down compilation and cause MSVC
internal compiler errors). Only use it when you have to (see example ahead).
*/
template<class...> struct conjunction : std::true_type {};
template<class B1> struct conjunction<B1> : B1 {};
template<class B1, class... Bn>
struct conjunction<B1, Bn...> : std::conditional<bool(B1::value), conjunction<Bn...>, B1>::type {};
template<class B> struct negation : std::integral_constant < bool, !B::value > {};
// dispatch utility (taken from ranges-v3)
template<unsigned N> struct priority_tag : priority_tag < N - 1 > {};
template<> struct priority_tag<0> {};
//////////////////
// constructors //
//////////////////
template<value_t> struct external_constructor;
template<>
struct external_constructor<value_t::boolean>
{
template<typename BasicJsonType>
static void construct(BasicJsonType& j, typename BasicJsonType::boolean_t b) noexcept
{
j.m_type = value_t::boolean;
j.m_value = b;
j.assert_invariant();
}
};
template<>
struct external_constructor<value_t::string>
{
template<typename BasicJsonType>
static void construct(BasicJsonType& j, const typename BasicJsonType::string_t& s)
{
j.m_type = value_t::string;
j.m_value = s;
j.assert_invariant();
}
};
template<>
struct external_constructor<value_t::number_float>
{
template<typename BasicJsonType>
static void construct(BasicJsonType& j, typename BasicJsonType::number_float_t val) noexcept
{
// replace infinity and NAN by null
if (not std::isfinite(val))
{
j = BasicJsonType{};
}
else
{
j.m_type = value_t::number_float;
j.m_value = val;
}
j.assert_invariant();
}
};
template<>
struct external_constructor<value_t::number_unsigned>
{
template<typename BasicJsonType>
static void construct(BasicJsonType& j, typename BasicJsonType::number_unsigned_t val) noexcept
{
j.m_type = value_t::number_unsigned;
j.m_value = val;
j.assert_invariant();
}
};
template<>
struct external_constructor<value_t::number_integer>
{
template<typename BasicJsonType>
static void construct(BasicJsonType& j, typename BasicJsonType::number_integer_t val) noexcept
{
j.m_type = value_t::number_integer;
j.m_value = val;
j.assert_invariant();
}
};
template<>
struct external_constructor<value_t::array>
{
template<typename BasicJsonType>
static void construct(BasicJsonType& j, const typename BasicJsonType::array_t& arr)
{
j.m_type = value_t::array;
j.m_value = arr;
j.assert_invariant();
}
template<typename BasicJsonType, typename CompatibleArrayType,
enable_if_t<not std::is_same<CompatibleArrayType,
typename BasicJsonType::array_t>::value,
int> = 0>
static void construct(BasicJsonType& j, const CompatibleArrayType& arr)
{
using std::begin;
using std::end;
j.m_type = value_t::array;
j.m_value.array = j.template create<typename BasicJsonType::array_t>(begin(arr), end(arr));
j.assert_invariant();
}
};
template<>
struct external_constructor<value_t::object>
{
template<typename BasicJsonType>
static void construct(BasicJsonType& j, const typename BasicJsonType::object_t& obj)
{
j.m_type = value_t::object;
j.m_value = obj;
j.assert_invariant();
}
template<typename BasicJsonType, typename CompatibleObjectType,
enable_if_t<not std::is_same<CompatibleObjectType,
typename BasicJsonType::object_t>::value,
int> = 0>
static void construct(BasicJsonType& j, const CompatibleObjectType& obj)
{
using std::begin;
using std::end;
j.m_type = value_t::object;
j.m_value.object = j.template create<typename BasicJsonType::object_t>(begin(obj), end(obj));
j.assert_invariant();
}
};
////////////////////////
// has_/is_ functions //
////////////////////////
/*!
@brief Helper to determine whether there's a key_type for T.
This helper is used to tell associative containers apart from other containers
such as sequence containers. For instance, `std::map` passes the test as it
contains a `mapped_type`, whereas `std::vector` fails the test.
@sa http://stackoverflow.com/a/7728728/266378
@since version 1.0.0, overworked in version 2.0.6
*/
#define NLOHMANN_JSON_HAS_HELPER(type) \
template<typename T> struct has_##type { \
private: \
template<typename U, typename = typename U::type> \
static int detect(U &&); \
static void detect(...); \
public: \
static constexpr bool value = \
std::is_integral<decltype(detect(std::declval<T>()))>::value; \
}
NLOHMANN_JSON_HAS_HELPER(mapped_type);
NLOHMANN_JSON_HAS_HELPER(key_type);
NLOHMANN_JSON_HAS_HELPER(value_type);
NLOHMANN_JSON_HAS_HELPER(iterator);
#undef NLOHMANN_JSON_HAS_HELPER
template<bool B, class RealType, class CompatibleObjectType>
struct is_compatible_object_type_impl : std::false_type {};
template<class RealType, class CompatibleObjectType>
struct is_compatible_object_type_impl<true, RealType, CompatibleObjectType>
{
static constexpr auto value =
std::is_constructible<typename RealType::key_type,
typename CompatibleObjectType::key_type>::value and
std::is_constructible<typename RealType::mapped_type,
typename CompatibleObjectType::mapped_type>::value;
};
template<class BasicJsonType, class CompatibleObjectType>
struct is_compatible_object_type
{
static auto constexpr value = is_compatible_object_type_impl <
conjunction<negation<std::is_same<void, CompatibleObjectType>>,
has_mapped_type<CompatibleObjectType>,
has_key_type<CompatibleObjectType>>::value,
typename BasicJsonType::object_t, CompatibleObjectType >::value;
};
template<typename BasicJsonType, typename T>
struct is_basic_json_nested_type
{
static auto constexpr value = std::is_same<T, typename BasicJsonType::iterator>::value or
std::is_same<T, typename BasicJsonType::const_iterator>::value or
std::is_same<T, typename BasicJsonType::reverse_iterator>::value or
std::is_same<T, typename BasicJsonType::const_reverse_iterator>::value or
std::is_same<T, typename BasicJsonType::json_pointer>::value;
};
template<class BasicJsonType, class CompatibleArrayType>
struct is_compatible_array_type
{
static auto constexpr value =
conjunction<negation<std::is_same<void, CompatibleArrayType>>,
negation<is_compatible_object_type<
BasicJsonType, CompatibleArrayType>>,
negation<std::is_constructible<typename BasicJsonType::string_t,
CompatibleArrayType>>,
negation<is_basic_json_nested_type<BasicJsonType, CompatibleArrayType>>,
has_value_type<CompatibleArrayType>,
has_iterator<CompatibleArrayType>>::value;
};
template<bool, typename, typename>
struct is_compatible_integer_type_impl : std::false_type {};
template<typename RealIntegerType, typename CompatibleNumberIntegerType>
struct is_compatible_integer_type_impl<true, RealIntegerType, CompatibleNumberIntegerType>
{
// is there an assert somewhere on overflows?
using RealLimits = std::numeric_limits<RealIntegerType>;
using CompatibleLimits = std::numeric_limits<CompatibleNumberIntegerType>;
static constexpr auto value =
std::is_constructible<RealIntegerType,
CompatibleNumberIntegerType>::value and
CompatibleLimits::is_integer and
RealLimits::is_signed == CompatibleLimits::is_signed;
};
template<typename RealIntegerType, typename CompatibleNumberIntegerType>
struct is_compatible_integer_type
{
static constexpr auto value =
is_compatible_integer_type_impl <
std::is_integral<CompatibleNumberIntegerType>::value and
not std::is_same<bool, CompatibleNumberIntegerType>::value,
RealIntegerType, CompatibleNumberIntegerType > ::value;
};
// trait checking if JSONSerializer<T>::from_json(json const&, udt&) exists
template<typename BasicJsonType, typename T>
struct has_from_json
{
private:
// also check the return type of from_json
template<typename U, typename = enable_if_t<std::is_same<void, decltype(uncvref_t<U>::from_json(
std::declval<BasicJsonType>(), std::declval<T&>()))>::value>>
static int detect(U&&);
static void detect(...);
public:
static constexpr bool value = std::is_integral<decltype(
detect(std::declval<typename BasicJsonType::template json_serializer<T, void>>()))>::value;
};
// This trait checks if JSONSerializer<T>::from_json(json const&) exists
// this overload is used for non-default-constructible user-defined-types
template<typename BasicJsonType, typename T>
struct has_non_default_from_json
{
private:
template <
typename U,
typename = enable_if_t<std::is_same<
T, decltype(uncvref_t<U>::from_json(std::declval<BasicJsonType>()))>::value >>
static int detect(U&&);
static void detect(...);
public:
static constexpr bool value = std::is_integral<decltype(detect(
std::declval<typename BasicJsonType::template json_serializer<T, void>>()))>::value;
};
// This trait checks if BasicJsonType::json_serializer<T>::to_json exists
template<typename BasicJsonType, typename T>
struct has_to_json
{
private:
template<typename U, typename = decltype(uncvref_t<U>::to_json(
std::declval<BasicJsonType&>(), std::declval<T>()))>
static int detect(U&&);
static void detect(...);
public:
static constexpr bool value = std::is_integral<decltype(detect(
std::declval<typename BasicJsonType::template json_serializer<T, void>>()))>::value;
};
/////////////
// to_json //
/////////////
template<typename BasicJsonType>
void to_json(BasicJsonType& j, typename BasicJsonType::boolean_t b) noexcept
{
external_constructor<value_t::boolean>::construct(j, b);
}
template<typename BasicJsonType, typename CompatibleString,
enable_if_t<std::is_constructible<typename BasicJsonType::string_t,
CompatibleString>::value, int> = 0>
void to_json(BasicJsonType& j, const CompatibleString& s)
{
external_constructor<value_t::string>::construct(j, s);
}
template<typename BasicJsonType, typename FloatType,
enable_if_t<std::is_floating_point<FloatType>::value, int> = 0>
void to_json(BasicJsonType& j, FloatType val) noexcept
{
external_constructor<value_t::number_float>::construct(j, static_cast<typename BasicJsonType::number_float_t>(val));
}
template <
typename BasicJsonType, typename CompatibleNumberUnsignedType,
enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_unsigned_t,
CompatibleNumberUnsignedType>::value, int> = 0 >
void to_json(BasicJsonType& j, CompatibleNumberUnsignedType val) noexcept
{
external_constructor<value_t::number_unsigned>::construct(j, static_cast<typename BasicJsonType::number_unsigned_t>(val));
}
template <
typename BasicJsonType, typename CompatibleNumberIntegerType,
enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_integer_t,
CompatibleNumberIntegerType>::value, int> = 0 >
void to_json(BasicJsonType& j, CompatibleNumberIntegerType val) noexcept
{
external_constructor<value_t::number_integer>::construct(j, static_cast<typename BasicJsonType::number_integer_t>(val));
}
template<typename BasicJsonType, typename UnscopedEnumType,
enable_if_t<is_unscoped_enum<UnscopedEnumType>::value, int> = 0>
void to_json(BasicJsonType& j, UnscopedEnumType e) noexcept
{
external_constructor<value_t::number_integer>::construct(j, e);
}
template <
typename BasicJsonType, typename CompatibleArrayType,
enable_if_t <
is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value or
std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value,
int > = 0 >
void to_json(BasicJsonType& j, const CompatibleArrayType& arr)
{
external_constructor<value_t::array>::construct(j, arr);
}
template <
typename BasicJsonType, typename CompatibleObjectType,
enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value,
int> = 0 >
void to_json(BasicJsonType& j, const CompatibleObjectType& arr)
{
external_constructor<value_t::object>::construct(j, arr);
}
///////////////
// from_json //
///////////////
// overloads for basic_json template parameters
template<typename BasicJsonType, typename ArithmeticType,
enable_if_t<std::is_arithmetic<ArithmeticType>::value and
not std::is_same<ArithmeticType,
typename BasicJsonType::boolean_t>::value,
int> = 0>
void get_arithmetic_value(const BasicJsonType& j, ArithmeticType& val)
{
switch (static_cast<value_t>(j))
{
case value_t::number_unsigned:
{
val = static_cast<ArithmeticType>(
*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
break;
}
case value_t::number_integer:
{
val = static_cast<ArithmeticType>(
*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
break;
}
case value_t::number_float:
{
val = static_cast<ArithmeticType>(
*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
break;
}
default:
{
JSON_THROW(
std::domain_error("type must be number, but is " + j.type_name()));
}
}
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b)
{
if (!j.is_boolean())
{
JSON_THROW(std::domain_error("type must be boolean, but is " + j.type_name()));
}
b = *j.template get_ptr<const typename BasicJsonType::boolean_t*>();
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::string_t& s)
{
if (!j.is_string())
{
JSON_THROW(std::domain_error("type must be string, but is " + j.type_name()));
}
s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::number_float_t& val)
{
get_arithmetic_value(j, val);
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::number_unsigned_t& val)
{
get_arithmetic_value(j, val);
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::number_integer_t& val)
{
get_arithmetic_value(j, val);
}
template<typename BasicJsonType, typename UnscopedEnumType,
enable_if_t<is_unscoped_enum<UnscopedEnumType>::value, int> = 0>
void from_json(const BasicJsonType& j, UnscopedEnumType& e)
{
typename std::underlying_type<UnscopedEnumType>::type val = e;
get_arithmetic_value(j, val);
e = static_cast<UnscopedEnumType>(val);
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::array_t& arr)
{
if (!j.is_array())
{
JSON_THROW(std::domain_error("type must be array, but is " + j.type_name()));
}
arr = *j.template get_ptr<const typename BasicJsonType::array_t*>();
}
// forward_list doesn't have an insert method
template<typename BasicJsonType, typename T, typename Allocator>
void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l)
{
// do not perform the check when user wants to retrieve jsons
// (except when it's null.. ?)
if (j.is_null())
{
JSON_THROW(std::domain_error("type must be array, but is " + j.type_name()));
}
if (not std::is_same<T, BasicJsonType>::value)
{
if (!j.is_array())
{
JSON_THROW(std::domain_error("type must be array, but is " + j.type_name()));
}
}
for (auto it = j.rbegin(), end = j.rend(); it != end; ++it)
{
l.push_front(it->template get<T>());
}
}
template<typename BasicJsonType, typename CompatibleArrayType>
void from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<0>)
{
using std::begin;
using std::end;
std::transform(j.begin(), j.end(),
std::inserter(arr, end(arr)), [](const BasicJsonType & i)
{
// get<BasicJsonType>() returns *this, this won't call a from_json
// method when value_type is BasicJsonType
return i.template get<typename CompatibleArrayType::value_type>();
});
}
template<typename BasicJsonType, typename CompatibleArrayType>
auto from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<1>)
-> decltype(
arr.reserve(std::declval<typename CompatibleArrayType::size_type>()),
void())
{
using std::begin;
using std::end;
arr.reserve(j.size());
std::transform(
j.begin(), j.end(), std::inserter(arr, end(arr)), [](const BasicJsonType & i)
{
// get<BasicJsonType>() returns *this, this won't call a from_json
// method when value_type is BasicJsonType
return i.template get<typename CompatibleArrayType::value_type>();
});
}
template<typename BasicJsonType, typename CompatibleArrayType,
enable_if_t<is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value and
not std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value, int> = 0>
void from_json(const BasicJsonType& j, CompatibleArrayType& arr)
{
if (j.is_null())
{
JSON_THROW(std::domain_error("type must be array, but is " + j.type_name()));
}
// when T == BasicJsonType, do not check if value_t is correct
if (not std::is_same<typename CompatibleArrayType::value_type, BasicJsonType>::value)
{
if (!j.is_array())
{
JSON_THROW(std::domain_error("type must be array, but is " + j.type_name()));
}
}
from_json_array_impl(j, arr, priority_tag<1> {});
}
template<typename BasicJsonType, typename CompatibleObjectType,
enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value, int> = 0>
void from_json(const BasicJsonType& j, CompatibleObjectType& obj)
{
if (!j.is_object())
{
JSON_THROW(std::domain_error("type must be object, but is " + j.type_name()));
}
auto inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
using std::begin;
using std::end;
// we could avoid the assignment, but this might require a for loop, which
// might be less efficient than the container constructor for some
// containers (would it?)
obj = CompatibleObjectType(begin(*inner_object), end(*inner_object));
}
// overload for arithmetic types, not chosen for basic_json template arguments
// (BooleanType, etc..); note: Is it really necessary to provide explicit
// overloads for boolean_t etc. in case of a custom BooleanType which is not
// an arithmetic type?
template<typename BasicJsonType, typename ArithmeticType,
enable_if_t <
std::is_arithmetic<ArithmeticType>::value and
not std::is_same<ArithmeticType, typename BasicJsonType::number_unsigned_t>::value and
not std::is_same<ArithmeticType, typename BasicJsonType::number_integer_t>::value and
not std::is_same<ArithmeticType, typename BasicJsonType::number_float_t>::value and
not std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
int> = 0>
void from_json(const BasicJsonType& j, ArithmeticType& val)
{
switch (static_cast<value_t>(j))
{
case value_t::number_unsigned:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
break;
}
case value_t::number_integer:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
break;
}
case value_t::number_float:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
break;
}
case value_t::boolean:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::boolean_t*>());
break;
}
default:
{
JSON_THROW(std::domain_error("type must be number, but is " + j.type_name()));
}
}
}
struct to_json_fn
{
template<typename BasicJsonType, typename T>
auto call(BasicJsonType& j, T&& val, priority_tag<1>) const noexcept(noexcept(to_json(j, std::forward<T>(val))))
-> decltype(to_json(j, std::forward<T>(val)), void())
{
return to_json(j, std::forward<T>(val));
}
template<typename BasicJsonType, typename T>
void call(BasicJsonType&, T&&, priority_tag<0>) const noexcept
{
static_assert(sizeof(BasicJsonType) == 0,
"could not find to_json() method in T's namespace");
}
public:
template<typename BasicJsonType, typename T>
void operator()(BasicJsonType& j, T&& val) const
noexcept(noexcept(std::declval<to_json_fn>().call(j, std::forward<T>(val), priority_tag<1> {})))
{
return call(j, std::forward<T>(val), priority_tag<1> {});
}
};
struct from_json_fn
{
private:
template<typename BasicJsonType, typename T>
auto call(const BasicJsonType& j, T& val, priority_tag<1>) const
noexcept(noexcept(from_json(j, val)))
-> decltype(from_json(j, val), void())
{
return from_json(j, val);
}
template<typename BasicJsonType, typename T>
void call(const BasicJsonType&, T&, priority_tag<0>) const noexcept
{
static_assert(sizeof(BasicJsonType) == 0,
"could not find from_json() method in T's namespace");
}
public:
template<typename BasicJsonType, typename T>
void operator()(const BasicJsonType& j, T& val) const
noexcept(noexcept(std::declval<from_json_fn>().call(j, val, priority_tag<1> {})))
{
return call(j, val, priority_tag<1> {});
}
};
// taken from ranges-v3
template<typename T>
struct static_const
{
static constexpr T value{};
};
template<typename T>
constexpr T static_const<T>::value;
/*!
@brief helper class to create locales with decimal point
This struct is used a default locale during the JSON serialization. JSON
requires the decimal point to be `.`, so this function overloads the
`do_decimal_point()` function to return `.`. This function is called by
float-to-string conversions to retrieve the decimal separator between integer
and fractional parts.
@sa https://github.com/nlohmann/json/issues/51#issuecomment-86869315
@since version 2.0.0
*/
struct DecimalSeparator : std::numpunct<char>
{
char do_decimal_point() const
{
return '.';
}
};
} // namespace detail
namespace
{
constexpr const auto& to_json = detail::static_const<detail::to_json_fn>::value;
constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value;
}
// default JSONSerializer template argument, doesn't care about template argument
// will use ADL for serialization
template<typename = void, typename = void>
struct adl_serializer
{
template<typename BasicJsonType, typename T>
static void from_json(BasicJsonType&& j, T& val) noexcept(noexcept(::nlohmann::from_json(std::forward<BasicJsonType>(j), val)))
{
::nlohmann::from_json(std::forward<BasicJsonType>(j), val);
}
template<typename BasicJsonType, typename T>
static void to_json(BasicJsonType& j, T&& val) noexcept(
noexcept(::nlohmann::to_json(j, std::forward<T>(val))))
{
::nlohmann::to_json(j, std::forward<T>(val));
}
};
/*!
@brief a class to store JSON values
@tparam ObjectType type for JSON objects (`std::map` by default; will be used
in @ref object_t)
@tparam ArrayType type for JSON arrays (`std::vector` by default; will be used
in @ref array_t)
@tparam StringType type for JSON strings and object keys (`std::string` by
default; will be used in @ref string_t)
@tparam BooleanType type for JSON booleans (`bool` by default; will be used
in @ref boolean_t)
@tparam NumberIntegerType type for JSON integer numbers (`int64_t` by
default; will be used in @ref number_integer_t)
@tparam NumberUnsignedType type for JSON unsigned integer numbers (@c
`uint64_t` by default; will be used in @ref number_unsigned_t)
@tparam NumberFloatType type for JSON floating-point numbers (`double` by
default; will be used in @ref number_float_t)
@tparam AllocatorType type of the allocator to use (`std::allocator` by
default)
@tparam JSONSerializer the serializer to resolve internal calls to `to_json()`
and `from_json()`
@requirement The class satisfies the following concept requirements:
- Basic
- [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible):
JSON values can be default constructed. The result will be a JSON null
value.
- [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible):
A JSON value can be constructed from an rvalue argument.
- [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible):
A JSON value can be copy-constructed from an lvalue expression.
- [MoveAssignable](http://en.cppreference.com/w/cpp/concept/MoveAssignable):
A JSON value van be assigned from an rvalue argument.
- [CopyAssignable](http://en.cppreference.com/w/cpp/concept/CopyAssignable):
A JSON value can be copy-assigned from an lvalue expression.
- [Destructible](http://en.cppreference.com/w/cpp/concept/Destructible):
JSON values can be destructed.
- Layout
- [StandardLayoutType](http://en.cppreference.com/w/cpp/concept/StandardLayoutType):
JSON values have
[standard layout](http://en.cppreference.com/w/cpp/language/data_members#Standard_layout):
All non-static data members are private and standard layout types, the
class has no virtual functions or (virtual) base classes.
- Library-wide
- [EqualityComparable](http://en.cppreference.com/w/cpp/concept/EqualityComparable):
JSON values can be compared with `==`, see @ref
operator==(const_reference,const_reference).
- [LessThanComparable](http://en.cppreference.com/w/cpp/concept/LessThanComparable):
JSON values can be compared with `<`, see @ref
operator<(const_reference,const_reference).
- [Swappable](http://en.cppreference.com/w/cpp/concept/Swappable):
Any JSON lvalue or rvalue of can be swapped with any lvalue or rvalue of
other compatible types, using unqualified function call @ref swap().
- [NullablePointer](http://en.cppreference.com/w/cpp/concept/NullablePointer):
JSON values can be compared against `std::nullptr_t` objects which are used
to model the `null` value.
- Container
- [Container](http://en.cppreference.com/w/cpp/concept/Container):
JSON values can be used like STL containers and provide iterator access.
- [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer);
JSON values can be used like STL containers and provide reverse iterator