X-Git-Url: http://git.tdb.fi/?p=libs%2Fcore.git;a=blobdiff_plain;f=source%2Fcore%2Fvariant.h;h=af204f2233f3c7759665a0f6b729bd52459d4326;hp=5de5a726f2dde80ee987c582851bbac2ca0523e6;hb=HEAD;hpb=5d51c374869f13f762039f58c03f3c5d75c12f07

diff --git a/source/core/variant.h b/source/core/variant.h
index 5de5a72..5cb1b93 100644
--- a/source/core/variant.h
+++ b/source/core/variant.h
@@ -5,17 +5,18 @@
 #include <type_traits>
 #include <typeinfo>
 #include "meta.h"
+#include "mspcore_api.h"
 
 namespace Msp {
 
-class type_mismatch: public std::runtime_error
+class MSPCORE_API type_mismatch: public std::runtime_error
 {
 public:
 	type_mismatch(const std::type_info &, const std::type_info &);
 };
 
 
-class Variant
+class MSPCORE_API Variant
 {
 public:
 	static constexpr unsigned INTERNAL_SIZE = 2*sizeof(void *);
@@ -25,30 +26,39 @@ public:
 		const std::type_info &(*get_type)();
 		bool (*compare)(const char *, const char *);
 		void (*clone)(char *, const char *);
+		void (*move)(char *, char *);
 		void (*destroy)(char *);
 	};
 
 private:
+	template<typename T>
+	using EnableNotVariant = typename std::enable_if<!std::is_same<typename std::remove_cv<typename std::remove_reference<T>::type>::type, Variant>::value>::type;
+
 	const Functions *funcs = nullptr;
 	alignas(void *) char storage[INTERNAL_SIZE];
 
 public:
 	Variant() = default;
-	template<typename T>
-	Variant(const T &v) { assign(v); }
+	template<typename T, typename = EnableNotVariant<T>>
+	Variant(T &&v) { assign(std::forward<T>(v)); }
 	Variant(const Variant &v) { copy_from(v); }
-	~Variant() { if(funcs) funcs->destroy(storage); }
+	Variant(Variant &&v) { move_from(std::move(v)); }
+	~Variant() { clear(); }
 
-	template<typename T>
-	Variant &operator=(const T &v) { assign(v); return *this; }
+	template<typename T, typename = EnableNotVariant<T>>
+	Variant &operator=(T &&v) { assign(std::forward<T>(v)); return *this; }
 
 	Variant &operator=(const Variant &v) { if(&v!=this) copy_from(v); return *this; }
+	Variant &operator=(Variant &&v) { if(&v!=this) move_from(std::move(v)); return *this; }
+
+	void clear();
 
 private:
 	template<typename T>
-	void assign(const T &);
+	void assign(T &&);
 
 	void copy_from(const Variant &);
+	void move_from(Variant &&);
 
 	template<typename T>
 	T &get();
@@ -95,12 +105,12 @@ private:
 	static const std::type_info &get_type() { return typeid(T); }
 
 	template<typename T>
-	static EnableSmall<T, void> create(char *s, const T &v)
-	{ new(s) T(v); }
+	static EnableSmall<T, void> create(char *s, T &&v)
+	{ new(s) typename std::remove_reference<T>::type(std::forward<T>(v)); }
 
 	template<typename T>
-	static EnableLarge<T, void> create(char *s, const T &v)
-	{ *reinterpret_cast<T **>(s) = new T(v); }
+	static EnableLarge<T, void> create(char *s, T &&v)
+	{ using V = typename std::remove_reference<T>::type; *reinterpret_cast<V **>(s) = new V(std::forward<T>(v)); }
 
 	template<typename T>
 	static typename std::enable_if<!IsEqualityComparable<T>::value, bool>::type compare(const char *, const char *)
@@ -122,6 +132,14 @@ private:
 	static EnableLarge<T, void> clone(char *s, const char *v)
 	{ *reinterpret_cast<T **>(s) = new T(**reinterpret_cast<const T *const *>(v)); }
 
+	template<typename T>
+	static EnableSmall<T, void> move(char *s, char *v)
+	{ new(s) T(std::move(*reinterpret_cast<T *>(v))); }
+
+	template<typename T>
+	static EnableLarge<T, void> move(char *s, char *v)
+	{ T *&p = *reinterpret_cast<T **>(v); *reinterpret_cast<T **>(s) = p; p = nullptr; }
+
 	template<typename T>
 	static EnableSmall<T, void> destroy(char *s)
 	{ reinterpret_cast<T *>(s)->~T(); }
@@ -132,26 +150,36 @@ private:
 };
 
 
-template<typename T>
-inline void Variant::assign(const T &v)
+inline void Variant::clear()
 {
 	if(funcs)
 		funcs->destroy(storage);
+	funcs = nullptr;
+}
 
-	funcs = get_functions<typename std::remove_cv<T>::type>();
-	create(storage, v);
+template<typename T>
+inline void Variant::assign(T &&v)
+{
+	clear();
+	funcs = get_functions<typename std::remove_cv<typename std::remove_reference<T>::type>::type>();
+	create(storage, std::forward<T>(v));
 }
 
 inline void Variant::copy_from(const Variant &v)
 {
-	if(funcs)
-		funcs->destroy(storage);
-
-	funcs = v.funcs;
-	if(funcs)
+	clear();
+	if((funcs = v.funcs))
 		funcs->clone(storage, v.storage);
 }
 
+inline void Variant::move_from(Variant &&v)
+{
+	clear();
+	if((funcs = v.funcs))
+		funcs->move(storage, v.storage);
+	v.clear();
+}
+
 template<typename T>
 inline T &Variant::get()
 {
@@ -182,6 +210,7 @@ inline const Variant::Functions *Variant::get_functions()
 		&get_type<T>,
 		&compare<T>,
 		&clone<T>,
+		&move<T>,
 		&destroy<T>
 	};
 	return &funcs;