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Unverified Commit e0c02c14 by Théo DELRIEU
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add detail/conversions/from_json.hpp

parent 7056b375
Showing with 331 additions and 301 deletions
Makefile
...@@ -7,7 +7,9 @@ SRCS = ${SRCDIR}/json.hpp \ ...@@ -7,7 +7,9 @@ SRCS = ${SRCDIR}/json.hpp \
${SRCDIR}/detail/macro_unscope.hpp \ ${SRCDIR}/detail/macro_unscope.hpp \
${SRCDIR}/detail/meta.hpp \ ${SRCDIR}/detail/meta.hpp \
${SRCDIR}/detail/exceptions.hpp \ ${SRCDIR}/detail/exceptions.hpp \
${SRCDIR}/detail/value_t.hpp ${SRCDIR}/detail/value_t.hpp \
${SRCDIR}/detail/conversions/from_json.hpp
......
src/detail/conversions/from_json.hpp 0 → 100644
#ifndef NLOHMANN_JSON_DETAIL_CONVERSIONS_FROM_JSON_HPP
#define NLOHMANN_JSON_DETAIL_CONVERSIONS_FROM_JSON_HPP
#include <array>
#include <tuple>
#include <utility>
#include <valarray>
#include "detail/exceptions.hpp"
#include "detail/macro_scope.hpp"
#include "detail/meta.hpp"
#include "detail/value_t.hpp"
namespace nlohmann
{
namespace detail
{
///////////////
// 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(type_error::create(302, "type must be number, but is " + std::string(j.type_name())));
}
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b)
{
if (JSON_UNLIKELY(not j.is_boolean()))
{
JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(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 (JSON_UNLIKELY(not j.is_string()))
{
JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(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 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);
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::array_t& arr)
{
if (JSON_UNLIKELY(not j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(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,
enable_if_t<std::is_convertible<BasicJsonType, T>::value, int> = 0>
void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l)
{
if (JSON_UNLIKELY(not j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
}
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<std::is_convertible<BasicJsonType, T>::value, int> = 0>
void from_json(const BasicJsonType& j, std::valarray<T>& l)
{
if (JSON_UNLIKELY(not j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
}
l.resize(j.size());
std::copy(j.m_value.array->begin(), j.m_value.array->end(), std::begin(l));
}
template<typename BasicJsonType, typename CompatibleArrayType>
void from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<0> /*unused*/)
{
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> /*unused*/)
-> decltype(
arr.reserve(std::declval<typename CompatibleArrayType::size_type>()),
void())
{
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 T, std::size_t N>
void from_json_array_impl(const BasicJsonType& j, std::array<T, N>& arr, priority_tag<2> /*unused*/)
{
for (std::size_t i = 0; i < N; ++i)
{
arr[i] = j.at(i).template get<T>();
}
}
template<typename BasicJsonType, typename CompatibleArrayType,
enable_if_t<is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value and
std::is_convertible<BasicJsonType, typename CompatibleArrayType::value_type>::value and
not std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value, int> = 0>
void from_json(const BasicJsonType& j, CompatibleArrayType& arr)
{
if (JSON_UNLIKELY(not j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
}
from_json_array_impl(j, arr, priority_tag<2> {});
}
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 (JSON_UNLIKELY(not j.is_object()))
{
JSON_THROW(type_error::create(302, "type must be object, but is " + std::string(j.type_name())));
}
auto inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
using value_type = typename CompatibleObjectType::value_type;
std::transform(
inner_object->begin(), inner_object->end(),
std::inserter(obj, obj.begin()),
[](typename BasicJsonType::object_t::value_type const & p)
{
return value_type(p.first, p.second.template get<typename CompatibleObjectType::mapped_type>());
});
}
// 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(type_error::create(302, "type must be number, but is " + std::string(j.type_name())));
}
}
template<typename BasicJsonType, typename A1, typename A2>
void from_json(const BasicJsonType& j, std::pair<A1, A2>& p)
{
p = {j.at(0).template get<A1>(), j.at(1).template get<A2>()};
}
template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
void from_json_tuple_impl(const BasicJsonType& j, Tuple& t, index_sequence<Idx...>)
{
t = std::make_tuple(j.at(Idx).template get<typename std::tuple_element<Idx, Tuple>::type>()...);
}
template<typename BasicJsonType, typename... Args>
void from_json(const BasicJsonType& j, std::tuple<Args...>& t)
{
from_json_tuple_impl(j, t, index_sequence_for<Args...> {});
}
struct from_json_fn
{
private:
template<typename BasicJsonType, typename T>
auto call(const BasicJsonType& j, T& val, priority_tag<1> /*unused*/) 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& /*unused*/, T& /*unused*/, priority_tag<0> /*unused*/) const noexcept
{
static_assert(sizeof(BasicJsonType) == 0,
"could not find from_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()(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> {});
}
};
}
/// 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
{
constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value;
}
}
#endif
src/detail/meta.hpp
...@@ -220,6 +220,16 @@ struct has_to_json ...@@ -220,6 +220,16 @@ struct has_to_json
static constexpr bool value = std::is_integral<decltype(detect( static constexpr bool value = std::is_integral<decltype(detect(
std::declval<typename BasicJsonType::template json_serializer<T, void>>()))>::value; std::declval<typename BasicJsonType::template json_serializer<T, void>>()))>::value;
}; };
// taken from ranges-v3
template<typename T>
struct static_const
{
static constexpr T value{};
};
template<typename T>
constexpr T static_const<T>::value;
} }
} }
......
src/json.hpp
...@@ -56,6 +56,7 @@ SOFTWARE. ...@@ -56,6 +56,7 @@ SOFTWARE.
#include "detail/meta.hpp" #include "detail/meta.hpp"
#include "detail/exceptions.hpp" #include "detail/exceptions.hpp"
#include "detail/value_t.hpp" #include "detail/value_t.hpp"
#include "detail/conversions/from_json.hpp"
/*! /*!
@brief namespace for Niels Lohmann @brief namespace for Niels Lohmann
...@@ -347,261 +348,6 @@ void to_json(BasicJsonType& j, const std::tuple<Args...>& t) ...@@ -347,261 +348,6 @@ void to_json(BasicJsonType& j, const std::tuple<Args...>& t)
to_json_tuple_impl(j, t, index_sequence_for<Args...> {}); to_json_tuple_impl(j, t, index_sequence_for<Args...> {});
} }
///////////////
// 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(type_error::create(302, "type must be number, but is " + std::string(j.type_name())));
}
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b)
{
if (JSON_UNLIKELY(not j.is_boolean()))
{
JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(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 (JSON_UNLIKELY(not j.is_string()))
{
JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(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 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);
}
template<typename BasicJsonType>
void from_json(const BasicJsonType& j, typename BasicJsonType::array_t& arr)
{
if (JSON_UNLIKELY(not j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(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,
enable_if_t<std::is_convertible<BasicJsonType, T>::value, int> = 0>
void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l)
{
if (JSON_UNLIKELY(not j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
}
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<std::is_convertible<BasicJsonType, T>::value, int> = 0>
void from_json(const BasicJsonType& j, std::valarray<T>& l)
{
if (JSON_UNLIKELY(not j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
}
l.resize(j.size());
std::copy(j.m_value.array->begin(), j.m_value.array->end(), std::begin(l));
}
template<typename BasicJsonType, typename CompatibleArrayType>
void from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<0> /*unused*/)
{
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> /*unused*/)
-> decltype(
arr.reserve(std::declval<typename CompatibleArrayType::size_type>()),
void())
{
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 T, std::size_t N>
void from_json_array_impl(const BasicJsonType& j, std::array<T, N>& arr, priority_tag<2> /*unused*/)
{
for (std::size_t i = 0; i < N; ++i)
{
arr[i] = j.at(i).template get<T>();
}
}
template<typename BasicJsonType, typename CompatibleArrayType,
enable_if_t<is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value and
std::is_convertible<BasicJsonType, typename CompatibleArrayType::value_type>::value and
not std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value, int> = 0>
void from_json(const BasicJsonType& j, CompatibleArrayType& arr)
{
if (JSON_UNLIKELY(not j.is_array()))
{
JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
}
from_json_array_impl(j, arr, priority_tag<2> {});
}
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 (JSON_UNLIKELY(not j.is_object()))
{
JSON_THROW(type_error::create(302, "type must be object, but is " + std::string(j.type_name())));
}
auto inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
using value_type = typename CompatibleObjectType::value_type;
std::transform(
inner_object->begin(), inner_object->end(),
std::inserter(obj, obj.begin()),
[](typename BasicJsonType::object_t::value_type const & p)
{
return value_type(p.first, p.second.template get<typename CompatibleObjectType::mapped_type>());
});
}
// 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(type_error::create(302, "type must be number, but is " + std::string(j.type_name())));
}
}
template<typename BasicJsonType, typename A1, typename A2>
void from_json(const BasicJsonType& j, std::pair<A1, A2>& p)
{
p = {j.at(0).template get<A1>(), j.at(1).template get<A2>()};
}
template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
void from_json_tuple_impl(const BasicJsonType& j, Tuple& t, index_sequence<Idx...>)
{
t = std::make_tuple(j.at(Idx).template get<typename std::tuple_element<Idx, Tuple>::type>()...);
}
template<typename BasicJsonType, typename... Args>
void from_json(const BasicJsonType& j, std::tuple<Args...>& t)
{
from_json_tuple_impl(j, t, index_sequence_for<Args...> {});
}
struct to_json_fn struct to_json_fn
{ {
private: private:
...@@ -635,49 +381,6 @@ struct to_json_fn ...@@ -635,49 +381,6 @@ struct to_json_fn
} }
}; };
struct from_json_fn
{
private:
template<typename BasicJsonType, typename T>
auto call(const BasicJsonType& j, T& val, priority_tag<1> /*unused*/) 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& /*unused*/, T& /*unused*/, priority_tag<0> /*unused*/) const noexcept
{
static_assert(sizeof(BasicJsonType) == 0,
"could not find from_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()(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;
//////////////////// ////////////////////
// input adapters // // input adapters //
//////////////////// ////////////////////
...@@ -6181,11 +5884,10 @@ class json_ref ...@@ -6181,11 +5884,10 @@ class json_ref
} // namespace detail } // namespace detail
/// namespace to hold default `to_json` / `from_json` functions /// namespace to hold default `to_json` function
namespace namespace
{ {
constexpr const auto& to_json = detail::static_const<detail::to_json_fn>::value; 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;
} }
template<typename, typename> template<typename, typename>
......
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