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#ifndef VARIANT_CAST_HPP
#define VARIANT_CAST_HPP
#include <type_traits>
namespace mapbox {
namespace util {
namespace detail {
template <class T>
class static_caster
{
public:
template <class V>
T& operator()(V& v) const
{
return static_cast<T&>(v);
}
};
template <class T>
class dynamic_caster
{
public:
using result_type = T&;
template <class V>
T& operator()(V& v, typename std::enable_if<!std::is_polymorphic<V>::value>::type* = nullptr) const
{
throw std::bad_cast();
}
template <class V>
T& operator()(V& v, typename std::enable_if<std::is_polymorphic<V>::value>::type* = nullptr) const
{
return dynamic_cast<T&>(v);
}
};
template <class T>
class dynamic_caster<T*>
{
public:
using result_type = T*;
template <class V>
T* operator()(V& v, typename std::enable_if<!std::is_polymorphic<V>::value>::type* = nullptr) const
{
return nullptr;
}
template <class V>
T* operator()(V& v, typename std::enable_if<std::is_polymorphic<V>::value>::type* = nullptr) const
{
return dynamic_cast<T*>(&v);
}
};
}
template <class T, class V>
typename detail::dynamic_caster<T>::result_type
dynamic_variant_cast(V& v)
{
return mapbox::util::apply_visitor(detail::dynamic_caster<T>(), v);
}
template <class T, class V>
typename detail::dynamic_caster<const T>::result_type
dynamic_variant_cast(const V& v)
{
return mapbox::util::apply_visitor(detail::dynamic_caster<const T>(), v);
}
template <class T, class V>
T& static_variant_cast(V& v)
{
return mapbox::util::apply_visitor(detail::static_caster<T>(), v);
}
template <class T, class V>
const T& static_variant_cast(const V& v)
{
return mapbox::util::apply_visitor(detail::static_caster<const T>(), v);
}
}
}
#endif // VARIANT_CAST_HPP
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