bsnes/nall/any.hpp

99 lines
2.8 KiB
C++

#ifndef NALL_ANY_HPP
#define NALL_ANY_HPP
#include <typeinfo>
#include <nall/traits.hpp>
namespace nall {
struct any {
bool empty() const { return container; }
void reset() { if(container) { delete container; container = nullptr; } }
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& operator=(const any& source) {
if(container) { delete container; container = nullptr; }
if(source.container) container = source.container->copy();
return *this;
}
any& operator=(any&& source) {
if(container) delete container;
container = source.container;
source.container = nullptr;
return *this;
}
any() = default;
any(const any& source) { operator=(source); }
any(any&& source) { operator=(std::move(source)); }
template<typename T> any(const T& value) { operator=(value); }
~any() { reset(); }
private:
struct placeholder {
virtual const std::type_info& type() const = 0;
virtual placeholder* copy() const = 0;
virtual ~placeholder() {}
};
placeholder* container = nullptr;
template<typename T> struct holder : placeholder {
T value;
const std::type_info& type() const { return typeid(T); }
placeholder* copy() const { return new holder(value); }
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