mirror of
https://github.com/nlohmann/json.git
synced 2024-08-24 22:07:02 +02:00
212 lines
7.3 KiB
C++
212 lines
7.3 KiB
C++
#pragma once
|
|
|
|
#include <ciso646> // not
|
|
#include <limits> // numeric_limits
|
|
#include <type_traits> // false_type, is_constructible, is_integral, is_same, true_type
|
|
#include <utility> // declval
|
|
|
|
#include <nlohmann/json_fwd.hpp>
|
|
#include <nlohmann/detail/meta/cpp_future.hpp>
|
|
#include <nlohmann/detail/meta/detected.hpp>
|
|
#include <nlohmann/detail/macro_scope.hpp>
|
|
|
|
namespace nlohmann
|
|
{
|
|
/*!
|
|
@brief detail namespace with internal helper functions
|
|
|
|
This namespace collects functions that should not be exposed,
|
|
implementations of some @ref basic_json methods, and meta-programming helpers.
|
|
|
|
@since version 2.1.0
|
|
*/
|
|
namespace detail
|
|
{
|
|
/////////////
|
|
// helpers //
|
|
/////////////
|
|
|
|
template<typename> struct is_basic_json : std::false_type {};
|
|
|
|
NLOHMANN_BASIC_JSON_TPL_DECLARATION
|
|
struct is_basic_json<NLOHMANN_BASIC_JSON_TPL> : std::true_type {};
|
|
|
|
//////////////////////////
|
|
// aliases for detected //
|
|
//////////////////////////
|
|
|
|
template <typename T>
|
|
using mapped_type_t = typename T::mapped_type;
|
|
|
|
template <typename T>
|
|
using key_type_t = typename T::key_type;
|
|
|
|
template <typename T>
|
|
using value_type_t = typename T::value_type;
|
|
|
|
template <typename T>
|
|
using iterator_t = typename T::iterator;
|
|
|
|
template <typename T, typename... Args>
|
|
using to_json_function = decltype(T::to_json(std::declval<Args>()...));
|
|
|
|
template <typename T, typename... Args>
|
|
using from_json_function = decltype(T::from_json(std::declval<Args>()...));
|
|
|
|
///////////////////
|
|
// is_ functions //
|
|
///////////////////
|
|
|
|
// source: https://stackoverflow.com/a/37193089/4116453
|
|
|
|
template <typename T, typename = void>
|
|
struct is_complete_type : std::false_type {};
|
|
|
|
template <typename T>
|
|
struct is_complete_type<T, decltype(void(sizeof(T)))> : std::true_type {};
|
|
|
|
template <typename BasicJsonType, typename CompatibleObjectType,
|
|
typename = void>
|
|
struct is_compatible_object_type_impl : std::false_type {};
|
|
|
|
template <typename BasicJsonType, typename CompatibleObjectType>
|
|
struct is_compatible_object_type_impl <
|
|
BasicJsonType, CompatibleObjectType,
|
|
enable_if_t<is_detected<mapped_type_t, CompatibleObjectType>::value and
|
|
is_detected<key_type_t, CompatibleObjectType>::value >>
|
|
{
|
|
|
|
using object_t = typename BasicJsonType::object_t;
|
|
|
|
// macOS's is_constructible does not play well with nonesuch...
|
|
static constexpr bool value =
|
|
std::is_constructible<typename object_t::key_type,
|
|
typename CompatibleObjectType::key_type>::value and
|
|
std::is_constructible<typename object_t::mapped_type,
|
|
typename CompatibleObjectType::mapped_type>::value;
|
|
};
|
|
|
|
template <typename BasicJsonType, typename CompatibleObjectType>
|
|
struct is_compatible_object_type
|
|
: is_compatible_object_type_impl<BasicJsonType, CompatibleObjectType> {};
|
|
|
|
template <typename BasicJsonType, typename CompatibleStringType,
|
|
typename = void>
|
|
struct is_compatible_string_type_impl : std::false_type {};
|
|
|
|
template <typename BasicJsonType, typename CompatibleStringType>
|
|
struct is_compatible_string_type_impl <
|
|
BasicJsonType, CompatibleStringType,
|
|
enable_if_t<is_detected_exact<typename BasicJsonType::string_t::value_type,
|
|
value_type_t, CompatibleStringType>::value >>
|
|
{
|
|
static constexpr auto value =
|
|
std::is_constructible<typename BasicJsonType::string_t, CompatibleStringType>::value;
|
|
};
|
|
|
|
template <typename BasicJsonType, typename CompatibleStringType>
|
|
struct is_compatible_string_type
|
|
: is_compatible_string_type_impl<BasicJsonType, CompatibleStringType> {};
|
|
|
|
template<typename BasicJsonType, typename T>
|
|
struct is_basic_json_nested_type
|
|
{
|
|
static auto constexpr value = std::is_same<T, typename BasicJsonType::iterator>::value or
|
|
std::is_same<T, typename BasicJsonType::const_iterator>::value or
|
|
std::is_same<T, typename BasicJsonType::reverse_iterator>::value or
|
|
std::is_same<T, typename BasicJsonType::const_reverse_iterator>::value;
|
|
};
|
|
|
|
template<class BasicJsonType, class CompatibleArrayType>
|
|
struct is_compatible_array_type
|
|
{
|
|
static auto constexpr value =
|
|
conjunction<negation<std::is_same<void, CompatibleArrayType>>,
|
|
negation<is_compatible_object_type<
|
|
BasicJsonType, CompatibleArrayType>>,
|
|
negation<std::is_constructible<typename BasicJsonType::string_t,
|
|
CompatibleArrayType>>,
|
|
negation<is_basic_json_nested_type<BasicJsonType, CompatibleArrayType>>,
|
|
is_detected<value_type_t, CompatibleArrayType>,
|
|
is_detected<iterator_t, 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
|
|
{
|
|
using serializer = typename BasicJsonType::template json_serializer<T, void>;
|
|
|
|
static constexpr bool value =
|
|
is_detected_exact<void, from_json_function, serializer,
|
|
const BasicJsonType&, T&>::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
|
|
{
|
|
using serializer = typename BasicJsonType::template json_serializer<T, void>;
|
|
|
|
static constexpr bool value =
|
|
is_detected_exact<T, from_json_function, serializer,
|
|
const BasicJsonType&>::value;
|
|
};
|
|
|
|
// This trait checks if BasicJsonType::json_serializer<T>::to_json exists
|
|
template<typename BasicJsonType, typename T>
|
|
struct has_to_json
|
|
{
|
|
using serializer = typename BasicJsonType::template json_serializer<T, void>;
|
|
|
|
static constexpr bool value =
|
|
is_detected_exact<void, to_json_function, serializer, BasicJsonType&,
|
|
T>::value;
|
|
};
|
|
|
|
template <typename BasicJsonType, typename CompatibleCompleteType>
|
|
struct is_compatible_complete_type
|
|
{
|
|
static constexpr bool value =
|
|
not std::is_base_of<std::istream, CompatibleCompleteType>::value and
|
|
not is_basic_json<CompatibleCompleteType>::value and
|
|
not is_basic_json_nested_type<BasicJsonType, CompatibleCompleteType>::value and
|
|
has_to_json<BasicJsonType, CompatibleCompleteType>::value;
|
|
};
|
|
|
|
template <typename BasicJsonType, typename CompatibleType>
|
|
struct is_compatible_type
|
|
: conjunction<is_complete_type<CompatibleType>,
|
|
is_compatible_complete_type<BasicJsonType, CompatibleType>>
|
|
{
|
|
};
|
|
}
|
|
}
|