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overworked type conversion

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This commit is contained in:
Niels
2015-04-08 22:23:40 +02:00
parent 0a96116b0c
commit 1bdb6acb1f
3 changed files with 1116 additions and 393 deletions
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192
src/json.hpp.re2c
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@ -58,16 +58,15 @@ namespace nlohmann
// Helper to determine whether there's a key_type for T.
// http://stackoverflow.com/a/7728728/266378
template<typename T>
struct has_key_type
struct has_mapped_type
{
private:
template<typename C> static char test(typename C::key_type*);
template<typename C> static char test(typename C::mapped_type*);
template<typename C> static int test(...);
public:
enum { value = sizeof(test<T>(0)) == sizeof(char) };
};
/*!
@brief JSON
@ -814,7 +813,7 @@ class basic_json
return m_type;
}
private:
//////////////////////
// value conversion //
//////////////////////
@ -822,89 +821,206 @@ class basic_json
/// get an object (explicit)
template <class T, typename
std::enable_if<
std::is_constructible<typename T::key_type, typename object_t::key_type>::value and
std::is_constructible<typename T::mapped_type, basic_json>::value, int>::type
= 0>
inline T get() const
std::is_convertible<typename object_t::key_type, typename T::key_type>::value and
std::is_convertible<basic_json, typename T::mapped_type>::value
, int>::type = 0>
inline T get_impl(T*) const
{
switch (m_type)
{
case (value_t::object):
{
return T(m_value.object->begin(), m_value.object->end());
}
default:
{
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
}
/// get an object (explicit)
inline object_t get_impl(object_t*) const
{
switch (m_type)
{
case (value_t::object):
{
return *(m_value.object);
}
default:
{
throw std::logic_error("cannot cast " + type_name() + " to object");
}
}
}
/// get an array (explicit)
template <class T, typename
std::enable_if<
not std::is_same<T, string_t>::value and
not has_key_type<T>::value and
std::is_constructible<typename T::value_type, basic_json>::value, int>::type
= 0>
inline T get() const
std::is_convertible<basic_json, typename T::value_type>::value and
not std::is_same<basic_json, typename T::value_type>::value and
not std::is_arithmetic<T>::value and
not std::is_convertible<std::string, T>::value and
not has_mapped_type<T>::value
, int>::type = 0>
inline T get_impl(T*) const
{
switch (m_type)
{
case (value_t::array):
return T(m_value.array->begin(), m_value.array->end());
{
T to_vector;
//to_vector.reserve(m_value.array->size());
std::transform(m_value.array->begin(), m_value.array->end(),
std::inserter(to_vector, to_vector.end()), [](basic_json i)
{
return i.get<typename T::value_type>();
});
return to_vector;
// return T(m_value.array->begin(), m_value.array->end());
}
default:
{
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
}
/// get an array (explicit)
template <class T, typename
std::enable_if<
std::is_convertible<basic_json, T>::value and
not std::is_same<basic_json, T>::value
, int>::type = 0>
inline std::vector<T> get_impl(std::vector<T>*) const
{
switch (m_type)
{
case (value_t::array):
{
std::vector<T> to_vector;
to_vector.reserve(m_value.array->size());
std::transform(m_value.array->begin(), m_value.array->end(),
std::inserter(to_vector, to_vector.end()), [](basic_json i)
{
return i.get<T>();
});
return to_vector;
}
default:
{
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
}
/// get an array (explicit)
template <class T, typename
std::enable_if<
std::is_same<basic_json, typename T::value_type>::value and
not has_mapped_type<T>::value
, int>::type = 0>
inline T get_impl(T*) const
{
switch (m_type)
{
case (value_t::array):
{
return T(m_value.array->begin(), m_value.array->end());
}
default:
{
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
}
inline array_t get_impl(array_t*) const
{
switch (m_type)
{
case (value_t::array):
{
return *(m_value.array);
}
default:
{
throw std::logic_error("cannot cast " + type_name() + " to array");
}
}
}
/// get a string (explicit)
template <typename T, typename
std::enable_if<
std::is_constructible<T, string_t>::value, int>::type
= 0>
inline T get() const
std::is_convertible<string_t, T>::value
, int>::type = 0>
inline T get_impl(T*) const
{
switch (m_type)
{
case (value_t::string):
{
return *m_value.string;
}
default:
{
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
/// get a boolean (explicit)
template <typename T, typename
std::enable_if<
std::is_same<boolean_t, T>::value, int>::type
= 0>
inline T get() const
{
switch (m_type)
{
case (value_t::boolean):
return m_value.boolean;
default:
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
}
/// get a number (explicit)
template<typename T, typename
std::enable_if<
not std::is_same<boolean_t, T>::value and
std::is_arithmetic<T>::value, int>::type
= 0>
inline T get() const
std::is_arithmetic<T>::value
, int>::type = 0>
inline T get_impl(T*) const
{
switch (m_type)
{
case (value_t::number_integer):
{
return static_cast<T>(m_value.number_integer);
}
case (value_t::number_float):
{
return static_cast<T>(m_value.number_float);
}
default:
{
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(T).name());
}
}
}
/// get a boolean (explicit)
inline boolean_t get_impl(boolean_t*) const
{
switch (m_type)
{
case (value_t::boolean):
{
return m_value.boolean;
}
default:
{
throw std::logic_error("cannot cast " + type_name() + " to " + typeid(boolean_t).name());
}
}
}
public:
/// get a value (explicit)
// <http://stackoverflow.com/a/8315197/266378>
template<typename T>
inline T get() const
{
return get_impl(static_cast<T*>(nullptr));
}
/// get a value (implicit)
template<typename T>
inline operator T() const
@ -1077,7 +1193,7 @@ class basic_json
// at only works for objects
if (m_type != value_t::object)
{
throw std::runtime_error("cannot use at with " + type_name());
throw std::runtime_error("cannot use erase with " + type_name());
}
return m_value.object->erase(key);