-/* $Id$
-
-This file is part of libmspcore
-Copyright © 2006-2007 Mikko Rasa, Mikkosoft Productions
-Distributed under the LGPL
-*/
-
#ifndef MSP_CORE_VARIANT_H_
#define MSP_CORE_VARIANT_H_
-#include "except.h"
+#include <stdexcept>
+#include <type_traits>
+#include <typeinfo>
#include "meta.h"
namespace Msp {
+class type_mismatch: public std::runtime_error
+{
+public:
+ type_mismatch(const std::type_info &, const std::type_info &);
+};
+
+
class Variant
{
private:
struct StoreBase
{
virtual ~StoreBase() { }
+
+ virtual const std::type_info &type_id() const = 0;
+ virtual StoreBase *clone() const = 0;
+ virtual bool type_equals(const StoreBase &) const = 0;
+ virtual bool value_equals(const StoreBase &) const = 0;
};
template<typename T>
{
T data;
- Store(T d): data(d) { }
+ Store(const T &d): data(d) { }
+
+ const std::type_info &type_id() const override { return typeid(T); }
+ StoreBase *clone() const override { return new Store<T>(data); }
+ bool type_equals(const StoreBase &s) const override { return dynamic_cast<const Store<T> *>(&s); }
+ bool value_equals(const StoreBase &s) const override { return _value_equals<T>(s); }
+
+ template<typename U>
+ typename std::enable_if<IsEqualityComparable<U>::value, bool>::type _value_equals(const StoreBase &s) const
+ { const Store<T> *t = dynamic_cast<const Store<T> *>(&s); return (t && t->data==data); }
+
+ template<typename U>
+ typename std::enable_if<!IsEqualityComparable<U>::value, bool>::type _value_equals(const StoreBase &) const
+ { return false; }
};
- StoreBase *store;
+ StoreBase *store = nullptr;
public:
- Variant(): store(0) { }
+ Variant() = default;
template<typename T>
- Variant(const T &v): store(new Store<typename RemoveConst<T>::Type>(v)) { }
+ Variant(const T &v): store(new Store<typename std::remove_cv<T>::type>(v)) { }
+ Variant(const Variant &v): store(v.store ? v.store->clone() : nullptr) { }
~Variant() { delete store; }
template<typename T>
Variant &operator=(const T &v)
{
delete store;
- store=new Store<typename RemoveConst<T>::Type>(v);
+ store = new Store<typename std::remove_cv<T>::type>(v);
+ return *this;
+ }
+
+ Variant &operator=(const Variant &v)
+ {
+ if(&v==this)
+ return *this;
+
+ delete store;
+ store = (v.store ? v.store->clone() : nullptr);
return *this;
}
+private:
template<typename T>
- T &value() const
+ Store<typename std::remove_cv<T>::type> *get_typed_store() const
{
- typedef typename RemoveConst<T>::Type NCT;
- Store<NCT> *s=dynamic_cast<Store<NCT> *>(store);
+ typedef typename std::remove_cv<T>::type NCT;
+ Store<NCT> *s = dynamic_cast<Store<NCT> *>(store);
if(!s)
- throw InvalidState("Type mismatch");
- return s->data;
+ throw type_mismatch(typeid(T), (store ? store->type_id() : typeid(void)));
+ return s;
+ }
+
+public:
+ template<typename T>
+ T &value()
+ {
+ return get_typed_store<T>()->data;
+ }
+
+ template<typename T>
+ const T &value() const
+ {
+ return get_typed_store<T>()->data;
}
template<typename T>
bool check_type() const
{
- return dynamic_cast<Store<typename RemoveConst<T>::Type> *>(store)!=0;
+ return dynamic_cast<Store<typename std::remove_cv<T>::type> *>(store);
}
+ bool check_same_type(const Variant &v) const
+ { return store && v.store && store->type_equals(*v.store); }
+
+ bool operator==(const Variant &v) const
+ { return store && v.store && store->value_equals(*v.store); }
+
+ bool operator!=(const Variant &v) const
+ { return !(operator==(v)); }
+
template<typename T>
operator T() const
{ return value<T>(); }