json/develop/detail/json_ref.hpp

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2017-08-14 16:14:27 +00:00
#ifndef NLOHMANN_JSON_DETAIL_JSON_REF_HPP
#define NLOHMANN_JSON_DETAIL_JSON_REF_HPP
#include <initializer_list>
#include <utility>
namespace nlohmann
{
namespace detail
{
template<typename BasicJsonType>
class json_ref
{
public:
using value_type = BasicJsonType;
json_ref(value_type&& value)
: owned_value(std::move(value)), value_ref(&owned_value), is_rvalue(true)
{}
json_ref(const value_type& value)
: value_ref(const_cast<value_type*>(&value)), is_rvalue(false)
{}
json_ref(std::initializer_list<json_ref> init)
: owned_value(init), value_ref(&owned_value), is_rvalue(true)
{}
template<class... Args>
json_ref(Args&& ... args)
: owned_value(std::forward<Args>(args)...), value_ref(&owned_value), is_rvalue(true)
{}
// class should be movable only
json_ref(json_ref&&) = default;
json_ref(const json_ref&) = delete;
json_ref& operator=(const json_ref&) = delete;
value_type moved_or_copied() const
{
if (is_rvalue)
{
return std::move(*value_ref);
}
return *value_ref;
}
value_type const& operator*() const
{
return *static_cast<value_type const*>(value_ref);
}
value_type const* operator->() const
{
return static_cast<value_type const*>(value_ref);
}
private:
mutable value_type owned_value = nullptr;
value_type* value_ref = nullptr;
const bool is_rvalue;
};
}
}
#endif