json/include/nlohmann/detail/conversions/to_json.hpp

349 lines
11 KiB
C++

#pragma once
#include <ciso646> // or, and, not
#include <iterator> // begin, end
#include <tuple> // tuple, get
#include <type_traits> // is_same, is_constructible, is_floating_point, is_enum, underlying_type
#include <utility> // move, forward, declval, pair
#include <valarray> // valarray
#include <vector> // vector
#include <nlohmann/detail/meta.hpp>
#include <nlohmann/detail/value_t.hpp>
namespace nlohmann
{
namespace detail
{
//////////////////
// 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<typename BasicJsonType>
static void construct(BasicJsonType& j, typename BasicJsonType::string_t&& s)
{
j.m_type = value_t::string;
j.m_value = std::move(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
{
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>
static void construct(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
{
j.m_type = value_t::array;
j.m_value = std::move(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<typename BasicJsonType>
static void construct(BasicJsonType& j, const std::vector<bool>& arr)
{
j.m_type = value_t::array;
j.m_value = value_t::array;
j.m_value.array->reserve(arr.size());
for (const bool x : arr)
{
j.m_value.array->push_back(x);
}
j.assert_invariant();
}
template<typename BasicJsonType, typename T,
enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
static void construct(BasicJsonType& j, const std::valarray<T>& arr)
{
j.m_type = value_t::array;
j.m_value = value_t::array;
j.m_value.array->resize(arr.size());
std::copy(std::begin(arr), std::end(arr), j.m_value.array->begin());
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>
static void construct(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
{
j.m_type = value_t::object;
j.m_value = std::move(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();
}
};
/////////////
// to_json //
/////////////
template<typename BasicJsonType, typename T,
enable_if_t<std::is_same<T, typename BasicJsonType::boolean_t>::value, int> = 0>
void to_json(BasicJsonType& j, 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>
void to_json(BasicJsonType& j, typename BasicJsonType::string_t&& s)
{
external_constructor<value_t::string>::construct(j, std::move(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 EnumType,
enable_if_t<std::is_enum<EnumType>::value, int> = 0>
void to_json(BasicJsonType& j, EnumType e) noexcept
{
using underlying_type = typename std::underlying_type<EnumType>::type;
external_constructor<value_t::number_integer>::construct(j, static_cast<underlying_type>(e));
}
template<typename BasicJsonType>
void to_json(BasicJsonType& j, const std::vector<bool>& e)
{
external_constructor<value_t::array>::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 T,
enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
void to_json(BasicJsonType& j, std::valarray<T> arr)
{
external_constructor<value_t::array>::construct(j, std::move(arr));
}
template<typename BasicJsonType>
void to_json(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
{
external_constructor<value_t::array>::construct(j, std::move(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& obj)
{
external_constructor<value_t::object>::construct(j, obj);
}
template<typename BasicJsonType>
void to_json(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
{
external_constructor<value_t::object>::construct(j, std::move(obj));
}
template<typename BasicJsonType, typename T, std::size_t N,
enable_if_t<not std::is_constructible<typename BasicJsonType::string_t, T (&)[N]>::value, int> = 0>
void to_json(BasicJsonType& j, T (&arr)[N])
{
external_constructor<value_t::array>::construct(j, arr);
}
template<typename BasicJsonType, typename... Args>
void to_json(BasicJsonType& j, const std::pair<Args...>& p)
{
j = {p.first, p.second};
}
template<typename IteratorType> class iteration_proxy; // TODO: Forward decl needed, maybe move somewhere else
template<typename BasicJsonType, typename T,
enable_if_t<std::is_same<T, typename iteration_proxy<typename BasicJsonType::iterator>::iteration_proxy_internal>::value, int> = 0>
void to_json(BasicJsonType& j, T b) noexcept
{
typename BasicJsonType::object_t tmp_obj;
tmp_obj[b.key()] = b.value(); // TODO: maybe there is a better way?
external_constructor<value_t::object>::construct(j, std::move(tmp_obj));
}
template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<Idx...>)
{
j = {std::get<Idx>(t)...};
}
template<typename BasicJsonType, typename... Args>
void to_json(BasicJsonType& j, const std::tuple<Args...>& t)
{
to_json_tuple_impl(j, t, index_sequence_for<Args...> {});
}
struct to_json_fn
{
private:
template<typename BasicJsonType, typename T>
auto call(BasicJsonType& j, T&& val, priority_tag<1> /*unused*/) 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& /*unused*/, T&& /*unused*/, priority_tag<0> /*unused*/) const noexcept
{
static_assert(sizeof(BasicJsonType) == 0,
"could not find to_json() method in T's namespace");
#ifdef _MSC_VER
// MSVC does not show a stacktrace for the above assert
using decayed = uncvref_t<T>;
static_assert(sizeof(typename decayed::force_msvc_stacktrace) == 0,
"forcing MSVC stacktrace to show which T we're talking about.");
#endif
}
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> {});
}
};
}
/// namespace to hold default `to_json` function
namespace
{
constexpr const auto& to_json = detail::static_const<detail::to_json_fn>::value;
}
}