bsnes/higan/nall/any.hpp

74 lines
2.3 KiB
C++
Executable File

#ifndef NALL_ANY_HPP
#define NALL_ANY_HPP
#include <typeinfo>
#include <nall/traits.hpp>
namespace nall {
struct any {
bool empty() const { return container; }
const std::type_info& type() const { return container ? container->type() : typeid(void); }
template<typename T> any& operator=(const T& value_) {
typedef typename type_if<
std::is_array<T>::value,
typename std::remove_extent<typename std::add_const<T>::type>::type*,
T
>::type auto_t;
if(type() == typeid(auto_t)) {
static_cast<holder<auto_t>*>(container)->value = (auto_t)value_;
} else {
if(container) delete container;
container = new holder<auto_t>((auto_t)value_);
}
return *this;
}
any() : container(nullptr) {}
~any() { if(container) delete container; }
template<typename T> any(const T& value_) : container(nullptr) { operator=(value_); }
private:
struct placeholder {
virtual const std::type_info& type() const = 0;
} *container;
template<typename T> struct holder : placeholder {
T value;
const std::type_info& type() const { return typeid(T); }
holder(const T& value_) : value(value_) {}
};
template<typename T> friend T any_cast(any&);
template<typename T> friend T any_cast(const any&);
template<typename T> friend T* any_cast(any*);
template<typename T> friend const T* any_cast(const any*);
};
template<typename T> T any_cast(any &value) {
typedef typename std::remove_reference<T>::type nonref;
if(value.type() != typeid(nonref)) throw;
return static_cast<any::holder<nonref>*>(value.container)->value;
}
template<typename T> T any_cast(const any &value) {
typedef const typename std::remove_reference<T>::type nonref;
if(value.type() != typeid(nonref)) throw;
return static_cast<any::holder<nonref>*>(value.container)->value;
}
template<typename T> T* any_cast(any *value) {
if(!value || value->type() != typeid(T)) return nullptr;
return &static_cast<any::holder<T>*>(value->container)->value;
}
template<typename T> const T* any_cast(const any *value) {
if(!value || value->type() != typeid(T)) return nullptr;
return &static_cast<any::holder<T>*>(value->container)->value;
}
}
#endif