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json/include/nlohmann/detail/conversions/from_json.hpp
Ferry Huberts 44d60f8d14 All: fix warnings when compiling with -Wswitch-enum 
Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
2021-08-12 16:33:50 +02:00

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#pragma once
#include <algorithm> // transform
#include <array> // array
#include <forward_list> // forward_list
#include <iterator> // inserter, front_inserter, end
#include <map> // map
#include <string> // string
#include <tuple> // tuple, make_tuple
#include <type_traits> // is_arithmetic, is_same, is_enum, underlying_type, is_convertible
#include <unordered_map> // unordered_map
#include <utility> // pair, declval
#include <valarray> // valarray
#include <nlohmann/detail/exceptions.hpp>
#include <nlohmann/detail/macro_scope.hpp>
#include <nlohmann/detail/meta/cpp_future.hpp>
#include <nlohmann/detail/meta/identity_tag.hpp>
#include <nlohmann/detail/meta/type_traits.hpp>
#include <nlohmann/detail/value_t.hpp>
namespace nlohmann
{
namespace detail
{
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename std::nullptr_t& n)
{
if (JSON_HEDLEY_UNLIKELY(!j.is_null()))
{
JSON_THROW(type_error::create(302, "type must be null, but is " + std::string(j.type_name()), j));
}
n = nullptr;
}
// overloads for basic_json template parameters
template < typename BasicJsonType, typename ArithmeticType,
enable_if_t < std::is_arithmetic<ArithmeticType>::value&&
!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;
}
case value_t::null:
case value_t::object:
case value_t::array:
case value_t::string:
case value_t::boolean:
case value_t::binary:
case value_t::discarded:
default:
JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name()), j));
}
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b)
{
if (JSON_HEDLEY_UNLIKELY(!j.is_boolean()))
{
JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(j.type_name()), j));
}
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 (JSON_HEDLEY_UNLIKELY(!j.is_string()))
{
JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name()), j));
}
s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
}
template <
typename BasicJsonType, typename ConstructibleStringType,
enable_if_t <
is_constructible_string_type<BasicJsonType, ConstructibleStringType>::value&&
!std::is_same<typename BasicJsonType::string_t,
ConstructibleStringType>::value,
int > = 0 >
void from_json(const BasicJsonType& j, ConstructibleStringType& s)
{
if (JSON_HEDLEY_UNLIKELY(!j.is_string()))
{
JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name()), j));
}
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 EnumType,
enable_if_t<std::is_enum<EnumType>::value, int> = 0>
void from_json(const BasicJsonType& j, EnumType& e)
{
typename std::underlying_type<EnumType>::type val;
get_arithmetic_value(j, val);
e = static_cast<EnumType>(val);
}
// forward_list doesn't have an insert method
template<typename BasicJsonType, typename T, typename Allocator,
enable_if_t<is_getable<BasicJsonType, T>::value, int> = 0>
void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l)
{
if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
}
l.clear();
std::transform(j.rbegin(), j.rend(),
std::front_inserter(l), [](const BasicJsonType & i)
{
return i.template get<T>();
});
}
// valarray doesn't have an insert method
template<typename BasicJsonType, typename T,
enable_if_t<is_getable<BasicJsonType, T>::value, int> = 0>
void from_json(const BasicJsonType& j, std::valarray<T>& l)
{
if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
}
l.resize(j.size());
std::transform(j.begin(), j.end(), std::begin(l),
[](const BasicJsonType & elem)
{
return elem.template get<T>();
});
}
template<typename BasicJsonType, typename T, std::size_t N>
auto from_json(const BasicJsonType& j, T (&arr)[N]) // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
-> decltype(j.template get<T>(), void())
{
for (std::size_t i = 0; i < N; ++i)
{
arr[i] = j.at(i).template get<T>();
}
}
template<typename BasicJsonType>
void from_json_array_impl(const BasicJsonType& j, typename BasicJsonType::array_t& arr, priority_tag<3> /*unused*/)
{
arr = *j.template get_ptr<const typename BasicJsonType::array_t*>();
}
template<typename BasicJsonType, typename T, std::size_t N>
auto from_json_array_impl(const BasicJsonType& j, std::array<T, N>& arr,
priority_tag<2> /*unused*/)
-> decltype(j.template get<T>(), void())
{
for (std::size_t i = 0; i < N; ++i)
{
arr[i] = j.at(i).template get<T>();
}
}
template<typename BasicJsonType, typename ConstructibleArrayType,
enable_if_t<
std::is_assignable<ConstructibleArrayType&, ConstructibleArrayType>::value,
int> = 0>
auto from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr, priority_tag<1> /*unused*/)
-> decltype(
arr.reserve(std::declval<typename ConstructibleArrayType::size_type>()),
j.template get<typename ConstructibleArrayType::value_type>(),
void())
{
using std::end;
ConstructibleArrayType ret;
ret.reserve(j.size());
std::transform(j.begin(), j.end(),
std::inserter(ret, end(ret)), [](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 ConstructibleArrayType::value_type>();
});
arr = std::move(ret);
}
template<typename BasicJsonType, typename ConstructibleArrayType,
enable_if_t<
std::is_assignable<ConstructibleArrayType&, ConstructibleArrayType>::value,
int> = 0>
void from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr,
priority_tag<0> /*unused*/)
{
using std::end;
ConstructibleArrayType ret;
std::transform(
j.begin(), j.end(), std::inserter(ret, end(ret)),
[](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 ConstructibleArrayType::value_type>();
});
arr = std::move(ret);
}
template < typename BasicJsonType, typename ConstructibleArrayType,
enable_if_t <
is_constructible_array_type<BasicJsonType, ConstructibleArrayType>::value&&
!is_constructible_object_type<BasicJsonType, ConstructibleArrayType>::value&&
!is_constructible_string_type<BasicJsonType, ConstructibleArrayType>::value&&
!std::is_same<ConstructibleArrayType, typename BasicJsonType::binary_t>::value&&
!is_basic_json<ConstructibleArrayType>::value,
int > = 0 >
auto from_json(const BasicJsonType& j, ConstructibleArrayType& arr)
-> decltype(from_json_array_impl(j, arr, priority_tag<3> {}),
j.template get<typename ConstructibleArrayType::value_type>(),
void())
{
if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
}
from_json_array_impl(j, arr, priority_tag<3> {});
}
template < typename BasicJsonType, typename T, std::size_t... Idx >
std::array<T, sizeof...(Idx)> from_json_inplace_array_impl(BasicJsonType&& j,
identity_tag<std::array<T, sizeof...(Idx)>> /*unused*/, index_sequence<Idx...> /*unused*/)
{
return { { std::forward<BasicJsonType>(j).at(Idx).template get<T>()... } };
}
template < typename BasicJsonType, typename T, std::size_t N >
auto from_json(BasicJsonType&& j, identity_tag<std::array<T, N>> tag)
-> decltype(from_json_inplace_array_impl(std::forward<BasicJsonType>(j), tag, make_index_sequence<N> {}))
{
if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
}
return from_json_inplace_array_impl(std::forward<BasicJsonType>(j), tag, make_index_sequence<N> {});
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::binary_t& bin)
{
if (JSON_HEDLEY_UNLIKELY(!j.is_binary()))
{
JSON_THROW(type_error::create(302, "type must be binary, but is " + std::string(j.type_name()), j));
}
bin = *j.template get_ptr<const typename BasicJsonType::binary_t*>();
}
template<typename BasicJsonType, typename ConstructibleObjectType,
enable_if_t<is_constructible_object_type<BasicJsonType, ConstructibleObjectType>::value, int> = 0>
void from_json(const BasicJsonType& j, ConstructibleObjectType& obj)
{
if (JSON_HEDLEY_UNLIKELY(!j.is_object()))
{
JSON_THROW(type_error::create(302, "type must be object, but is " + std::string(j.type_name()), j));
}
ConstructibleObjectType ret;
const auto* inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
using value_type = typename ConstructibleObjectType::value_type;
std::transform(
inner_object->begin(), inner_object->end(),
std::inserter(ret, ret.begin()),
[](typename BasicJsonType::object_t::value_type const & p)
{
return value_type(p.first, p.second.template get<typename ConstructibleObjectType::mapped_type>());
});
obj = std::move(ret);
}
// 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&&
!std::is_same<ArithmeticType, typename BasicJsonType::number_unsigned_t>::value&&
!std::is_same<ArithmeticType, typename BasicJsonType::number_integer_t>::value&&
!std::is_same<ArithmeticType, typename BasicJsonType::number_float_t>::value&&
!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;
}
case value_t::null:
case value_t::object:
case value_t::array:
case value_t::string:
case value_t::binary:
case value_t::discarded:
default:
JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name()), j));
}
}
template<typename BasicJsonType, typename... Args, std::size_t... Idx>
std::tuple<Args...> from_json_tuple_impl_base(BasicJsonType&& j, index_sequence<Idx...> /*unused*/)
{
return std::make_tuple(std::forward<BasicJsonType>(j).at(Idx).template get<Args>()...);
}
template < typename BasicJsonType, class A1, class A2 >
std::pair<A1, A2> from_json_tuple_impl(BasicJsonType&& j, identity_tag<std::pair<A1, A2>> /*unused*/, priority_tag<0> /*unused*/)
{
return {std::forward<BasicJsonType>(j).at(0).template get<A1>(),
std::forward<BasicJsonType>(j).at(1).template get<A2>()};
}
template<typename BasicJsonType, typename A1, typename A2>
void from_json_tuple_impl(BasicJsonType&& j, std::pair<A1, A2>& p, priority_tag<1> /*unused*/)
{
p = from_json_tuple_impl(std::forward<BasicJsonType>(j), identity_tag<std::pair<A1, A2>> {}, priority_tag<0> {});
}
template<typename BasicJsonType, typename... Args>
std::tuple<Args...> from_json_tuple_impl(BasicJsonType&& j, identity_tag<std::tuple<Args...>> /*unused*/, priority_tag<2> /*unused*/)
{
return from_json_tuple_impl_base<BasicJsonType, Args...>(std::forward<BasicJsonType>(j), index_sequence_for<Args...> {});
}
template<typename BasicJsonType, typename... Args>
void from_json_tuple_impl(BasicJsonType&& j, std::tuple<Args...>& t, priority_tag<3> /*unused*/)
{
t = from_json_tuple_impl_base<BasicJsonType, Args...>(std::forward<BasicJsonType>(j), index_sequence_for<Args...> {});
}
template<typename BasicJsonType, typename TupleRelated>
auto from_json(BasicJsonType&& j, TupleRelated&& t)
-> decltype(from_json_tuple_impl(std::forward<BasicJsonType>(j), std::forward<TupleRelated>(t), priority_tag<3> {}))
{
if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
}
return from_json_tuple_impl(std::forward<BasicJsonType>(j), std::forward<TupleRelated>(t), priority_tag<3> {});
}
template < typename BasicJsonType, typename Key, typename Value, typename Compare, typename Allocator,
typename = enable_if_t < !std::is_constructible <
typename BasicJsonType::string_t, Key >::value >>
void from_json(const BasicJsonType& j, std::map<Key, Value, Compare, Allocator>& m)
{
if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
}
m.clear();
for (const auto& p : j)
{
if (JSON_HEDLEY_UNLIKELY(!p.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name()), j));
}
m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
}
}
template < typename BasicJsonType, typename Key, typename Value, typename Hash, typename KeyEqual, typename Allocator,
typename = enable_if_t < !std::is_constructible <
typename BasicJsonType::string_t, Key >::value >>
void from_json(const BasicJsonType& j, std::unordered_map<Key, Value, Hash, KeyEqual, Allocator>& m)
{
if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
}
m.clear();
for (const auto& p : j)
{
if (JSON_HEDLEY_UNLIKELY(!p.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name()), j));
}
m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
}
}
struct from_json_fn
{
template<typename BasicJsonType, typename T>
auto operator()(const BasicJsonType& j, T&& val) const
noexcept(noexcept(from_json(j, std::forward<T>(val))))
-> decltype(from_json(j, std::forward<T>(val)))
{
return from_json(j, std::forward<T>(val));
}
};
} // namespace detail
/// namespace to hold default `from_json` function
/// to see why this is required:
/// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
namespace // NOLINT(cert-dcl59-cpp,fuchsia-header-anon-namespaces,google-build-namespaces)
{
constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value; // NOLINT(misc-definitions-in-headers)
} // namespace
} // namespace nlohmann
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