X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fcore%2Fvariant.h;h=eaf5a34e171ea3423018548a189f7fd8e250ba9a;hb=3bfc22d12b893d94cbb4697a77b7cababcbbd921;hp=b81bb506f300f8df2f215a63a427a7df38af7f7e;hpb=773a089db67a6293ac057e3160a43cceab8e5c1e;p=libs%2Fcore.git

diff --git a/source/core/variant.h b/source/core/variant.h
index b81bb50..eaf5a34 100644
--- a/source/core/variant.h
+++ b/source/core/variant.h
@@ -1,23 +1,31 @@
-/* $Id$
-
-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>
@@ -25,40 +33,88 @@ private:
 	{
 		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(T v): store(new Store<T>(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=(T v)
+	Variant &operator=(const T &v)
+	{
+		delete store;
+		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=new Store<T>(v);
+		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
 	{
-		Store<T> *s=dynamic_cast<Store<T> *>(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<T> *>(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>(); }