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  1. #include <iostream>
  2. #include <memory>
  3. #include <map>
  4.  
  5. using namespace std;
  6.  
  7. #define Msg1(msg) {cout << (msg) << endl;}
  8. #define Msg2(msg1,msg2) {cout << (msg1) << (msg2) << endl;}
  9. #define Msg2s(msg1,msg2,sp) {cout << (msg1) << (sp) << (msg2) << endl;}
  10.  
  11. #define DebugMode
  12.  
  13. #ifdef DebugMode
  14. # define DebugMsg1(msg) Msg1(msg)
  15. #else
  16. # define DebugMsg1(msg)
  17. #endif
  18.  
  19.  
  20. class NullPtr_t
  21. {
  22. public:
  23. 	NullPtr_t() : zero(NULL) {}
  24. 	template< class T >
  25. 	operator T* () const { return NULL; }
  26. 	template< class T, class C >
  27. 	operator T C::* () const { return NULL; }
  28. private:
  29. 	void operator &() const;
  30. 	void *zero;
  31. };
  32.  
  33. inline NullPtr_t getNullPtr() { return NullPtr_t(); }
  34. #define nullptr getNullPtr()
  35.  
  36. template< class T >
  37. class BasePtr
  38. {
  39. 	typedef BasePtr< T > ThisPtr;
  40.  
  41. 	virtual T* get() = 0;
  42. 	virtual T& ref() = 0;
  43.  
  44. 	friend bool operator == (ThisPtr& a, ThisPtr& b) {
  45. 		return a.get() == b.get();
  46. 	}
  47.  
  48. 	friend bool operator != (ThisPtr& a, ThisPtr& b) {
  49. 		return a.get() != b.get();
  50. 	}
  51. };
  52.  
  53. template< class T, class A = allocator< T > >
  54. class FooPtr : public BasePtr< T >
  55. {
  56. 	typedef T FOO, *LPFOO;
  57. 	typedef A ALLO;
  58. 	typedef map< LPFOO, int > REFMAP; 
  59. 	typedef FooPtr< FOO , ALLO > ThisPtr;
  60.  
  61. private:
  62. 	LPFOO _ptr;
  63.  
  64. 	REFMAP& refmap() {
  65. 		static REFMAP refm;
  66. 		return refm;
  67. 	}
  68.  
  69. public:
  70.  
  71. 	FooPtr() : _ptr(nullptr) {
  72. 	}
  73.  
  74.  	FooPtr(const LPFOO foo) : _ptr(nullptr) {
  75.  		DebugMsg1( "FooPtr(LPFOO)" );
  76.  		reset(foo);
  77.  	}
  78.  
  79.  	FooPtr(const ThisPtr& other) : _ptr(nullptr) {
  80.  		DebugMsg1( "FooPtr(ThisPtr)" );
  81.  		copy(other);
  82.  	} 
  83.  
  84.  	~FooPtr() {
  85.  		clear();
  86.  	}
  87.  
  88.  	FOO& operator *() const { return *_ptr; }
  89.  
  90. 	operator LPFOO const () { return _ptr; }
  91.  
  92. 	LPFOO operator -> () const { return _ptr; }
  93.  
  94. 	LPFOO get() { return _ptr; }
  95.  
  96. 	FOO& ref() { return *_ptr; }
  97.  
  98. 	ThisPtr& operator = (const ThisPtr& other) {
  99. 		DebugMsg1( "ope = ThisPtr" );
  100. 		copy(other);
  101. 		return *this;
  102. 	}
  103.  
  104. 	ThisPtr& operator = (const LPFOO foo) {
  105. 		DebugMsg1( "ope = LPFOO" );
  106. 		reset(foo);
  107. 		return *this;
  108. 	}
  109.  
  110. 	void reset(const LPFOO foo) {
  111. 		clear();
  112. 		if (foo == nullptr) {
  113. 			return;
  114. 		}
  115.  
  116. 		_ptr = foo;
  117.  
  118. 		REFMAP& m = refmap();
  119. 		m[_ptr]++;
  120. 	}
  121.  
  122. 	void copy(const ThisPtr& other) {
  123. 		clear();
  124. 		_ptr = other._ptr;
  125. 		if (_ptr != nullptr) {
  126. 			REFMAP& m = refmap();
  127. 			if (m[_ptr]) {
  128. 				m[_ptr]++;
  129. 			} else {
  130. 				 // missing
  131. 				_ptr = nullptr;
  132. 				// or throw Exception
  133. 			}
  134. 		}
  135. 	}
  136.  
  137. 	void clear() {
  138. 		if (_ptr == nullptr) {
  139. 			return;
  140. 		}
  141. 		REFMAP& m = refmap();
  142. 		m[_ptr]--;
  143. 		if (m[_ptr] == 0) {
  144. 			ALLO allo;
  145. 			allo.destroy(_ptr);
  146. 			allo.deallocate(_ptr, 1);
  147. 		}
  148. 		_ptr = nullptr;
  149. 	}
  150.  
  151. };
  152.  
  153.  
  154. class Hoge
  155. {
  156. public:
  157. 	Hoge() : id(counter()) {
  158. 		Msg2( "Hoge() : ", id );
  159. 	}
  160. 	Hoge(const Hoge&) : id(counter()) {
  161. 		Msg2( "Hoge(Hoge&) : ", id );
  162. 	}
  163.  
  164. 	~Hoge() {
  165. 		Msg2( "~Hoge() : ", id );
  166. 	}
  167.  
  168. 	operator int () {
  169. 		return id;
  170. 	}
  171.  
  172. 	void print() {
  173. 		Msg2( "Hoge method : ", id );
  174. 	}
  175.  
  176. private:
  177. 	const int id;
  178. 	static int counter() {
  179. 		static int c = 0;
  180. 		return ++c;
  181. 	}
  182. };
  183.  
  184. FooPtr<Hoge> getHoge() {
  185. 	FooPtr<Hoge> temp(new Hoge);
  186. 	return temp;
  187. }
  188.  
  189. int main() {
  190. 	Msg1( "** begin of program **" );
  191.  
  192. 	FooPtr<Hoge> hoge1(new Hoge);
  193.  
  194. 	{
  195. 		Msg1( "-- test 1 --" );
  196. 		FooPtr<Hoge> empty;
  197.  
  198. 		empty = hoge1;
  199.  
  200. 		Msg2( "hoge1: ", *hoge1 );
  201. 		Msg2( "empty: ", *empty );
  202. 	}
  203.  
  204. 	{
  205. 		Msg1( "-- test 2 --" );
  206. 		FooPtr<Hoge> hoge2(hoge1);
  207.  
  208. 		Msg2( "hoge1: ", *hoge1 );
  209. 		Msg2( "hoge2: ", *hoge2 );
  210. 	}
  211.  
  212. 	{
  213. 		Msg1( "-- test 3 --" );
  214. 		FooPtr<Hoge> hoge3 = hoge1;
  215.  
  216. 		Msg2( "hoge1: ", *hoge1 );
  217. 		Msg2( "hgoe3: ", *hoge3 );
  218. 	}
  219.  
  220. 	{
  221. 		Msg1( "-- test 4 --" );
  222. 		FooPtr<Hoge> hoge4 = hoge1;
  223. 		hoge1 = nullptr;
  224.  
  225. 		Msg2( "hoge4: ", *hoge4 );
  226. 	}
  227.  
  228. 	{
  229. 		Msg1( "-- test 5 --" );
  230. 		hoge1 = new Hoge;
  231.  
  232. 		Msg2( "hoge1: ", *hoge1 );
  233. 	}
  234.  
  235. 	{
  236. 		Msg1( "-- test 6 --" );
  237.  
  238. 		hoge1->print();
  239. 	}
  240.  
  241. 	{
  242. 		Msg1( "-- test 7 --" );
  243.  
  244. 		getHoge();
  245.  
  246. 		hoge1 = getHoge();
  247. 	}
  248.  
  249. 	{
  250. 		Msg1( "-- test 8 --" );
  251.  
  252. 		Hoge *h1 = hoge1;
  253.  
  254. 		h1->print();
  255.  
  256. 		h1 = nullptr;
  257. 	}
  258.  
  259. 	{
  260. 		Msg1( "-- test 9 --" );
  261.  
  262. 		FooPtr<Hoge> f1(hoge1);
  263. 		FooPtr<Hoge> f2(new Hoge);
  264.  
  265. 		if (f1 == hoge1) {
  266. 			Msg1( "f1 == hoge1" );
  267. 		} else {
  268. 			Msg1( "not f1 == hoge1 (!?)" );
  269. 		}
  270.  
  271. 		if (f2 != hoge1) {
  272. 			Msg1( "f2 != hoge1" );
  273. 		} else {
  274. 			Msg1( "not f2 != hoge1 (!?)" );
  275. 		}
  276. 	}
  277.  
  278. 	{
  279. 		Msg1( "-- test 10 --" );
  280. 		FooPtr<Hoge> h3 = new Hoge;
  281. 		hoge1 = h3;
  282. 	}
  283.  
  284. 	Msg1( "** end of program **" );
  285. 	return 0;
  286. }
Success #stdin #stdout 0s 3484KB
comments (?)
stdin 
Standard input is empty
stdout 
** begin of program **
Hoge() : 1
FooPtr(LPFOO)
-- test 1 --
ope = ThisPtr
hoge1: 1
empty: 1
-- test 2 --
FooPtr(ThisPtr)
hoge1: 1
hoge2: 1
-- test 3 --
FooPtr(ThisPtr)
hoge1: 1
hgoe3: 1
-- test 4 --
FooPtr(ThisPtr)
ope = LPFOO
hoge4: 1
~Hoge() : 1
-- test 5 --
Hoge() : 2
ope = LPFOO
hoge1: 2
-- test 6 --
Hoge method : 2
-- test 7 --
Hoge() : 3
FooPtr(LPFOO)
~Hoge() : 3
Hoge() : 4
FooPtr(LPFOO)
ope = ThisPtr
~Hoge() : 2
-- test 8 --
Hoge method : 4
-- test 9 --
FooPtr(ThisPtr)
Hoge() : 5
FooPtr(LPFOO)
f1 == hoge1
f2 != hoge1
~Hoge() : 5
-- test 10 --
Hoge() : 6
FooPtr(LPFOO)
ope = ThisPtr
~Hoge() : 4
** end of program **
~Hoge() : 6
https://ideone.com/1Hr0i2
language:
C++ (gcc 8.3)
created:
10 years ago
visibility:
public

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