/*
* Copyright (c) 1997-1999
* Silicon Graphics Computer Systems, Inc.
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation.  Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose.  It is provided "as is" without express or implied warranty.
*
*/
 
#ifndef __SGI_STL_MEMORY
#define __SGI_STL_MEMORY
 
#include <stl_algobase.h>
#include <stl_alloc.h>
#include <stl_construct.h>
#include <stl_tempbuf.h>
#include <stl_uninitialized.h>
#include <stl_raw_storage_iter.h>
 
 
__STL_BEGIN_NAMESPACE
// 如果定義了auto_ptr轉(zhuǎn)換以及支持成員函數(shù)模板
#if defined(__SGI_STL_USE_AUTO_PTR_CONVERSIONS) && \
	defined(__STL_MEMBER_TEMPLATES)
// 定義auto_ptr_ref template結(jié)構(gòu)體①
template<class _Tp1> struct auto_ptr_ref {
	_Tp1* _M_ptr;
	auto_ptr_ref(_Tp1* __p) : _M_ptr(__p) {}
};
 
#endif
 
template <class _Tp>
class auto_ptr {
private:
	_Tp* _M_ptr;
 
public:
	typedef _Tp element_type;
	// explicit修飾構(gòu)造函數(shù)，防止從原始指針隱式轉(zhuǎn)換
	explicit auto_ptr(_Tp* __p = 0) __STL_NOTHROW : _M_ptr(__p) {}
	// Copy構(gòu)造函數(shù)，注意這里是直接引用傳參（非const），同時(shí)轉(zhuǎn)移指針?biāo)袡?quán)
	auto_ptr(auto_ptr& __a) __STL_NOTHROW : _M_ptr(__a.release()) {}
 
// 如果允許定義成員函數(shù)模板（Member Function Templates）②
#ifdef __STL_MEMBER_TEMPLATES
	// 如果可以從_Tp1*轉(zhuǎn)換為_Tp*，則可以從auto_ptr<_Tp1>構(gòu)造auto_ptr<_Tp>
	// 同時(shí)轉(zhuǎn)移指針?biāo)袡?quán)
	template <class _Tp1>
	auto_ptr(auto_ptr<_Tp1>& __a) __STL_NOTHROW
		: _M_ptr(__a.release()) {}
#endif /* __STL_MEMBER_TEMPLATES */
 
	// 賦值操作符，同樣是非const引用傳參，有證同測(cè)試③
	auto_ptr& operator=(auto_ptr& __a) __STL_NOTHROW {
		// 如果是自我賦值，就直接返回
		if (&__a != this) {
			delete _M_ptr;
			_M_ptr = __a.release();
		}
		return *this;
	}
 
#ifdef __STL_MEMBER_TEMPLATES
	// 賦值操作符的Member Function Templates
	template <class _Tp1>
	auto_ptr& operator=(auto_ptr<_Tp1>& __a) __STL_NOTHROW {
		if (__a.get() != this->get()) {
			delete _M_ptr;
			_M_ptr = __a.release();
		}
		return *this;
	}
#endif /* __STL_MEMBER_TEMPLATES */
 
	// Note: The C++ standard says there is supposed to be an empty throw
	// specification here, but omitting it is standard conforming.  Its 
	// presence can be detected only if _Tp::~_Tp() throws, but (17.4.3.6/2)
	// this is prohibited.
	// auto_ptr的析構(gòu)函數(shù)
	~auto_ptr() { delete _M_ptr; }
	// operator*定義，返回值
	_Tp& operator*() const __STL_NOTHROW {
		return *_M_ptr;
	}
	// operator->定義，返回指針
	_Tp* operator->() const __STL_NOTHROW {
		return _M_ptr;
	}
	// const成員函數(shù)get定義，返回指針
	_Tp* get() const __STL_NOTHROW {
		return _M_ptr;
	}
	// release函數(shù)定義，釋放指針
	_Tp* release() __STL_NOTHROW {
		_Tp* __tmp = _M_ptr;
		_M_ptr = 0;
		return __tmp;
	}
	// reset函數(shù)定義，重置指針
	void reset(_Tp* __p = 0) __STL_NOTHROW {
		if (__p != _M_ptr) {
			delete _M_ptr;
			_M_ptr = __p;
		}
	}
 
	// According to the C++ standard, these conversions are required.  Most
	// present-day compilers, however, do not enforce that requirement---and, 
	// in fact, most present-day compilers do not support the language 
	// features that these conversions rely on.
 
#if defined(__SGI_STL_USE_AUTO_PTR_CONVERSIONS) && \
	defined(__STL_MEMBER_TEMPLATES)
 
public:
	// 從auto_ptr_ref<_Tp>構(gòu)造auto_ptr<_Tp>
	auto_ptr(auto_ptr_ref<_Tp> __ref) __STL_NOTHROW
		: _M_ptr(__ref._M_ptr) {}
	// 從auto_ptr_ref<_Tp>對(duì)auto_ptr<_Tp>進(jìn)行賦值操作。
	// 注意這里是普通傳參，沒有引用④
	auto_ptr& operator=(auto_ptr_ref<_Tp> __ref) __STL_NOTHROW {
		if (__ref._M_ptr != this->get()) {
			delete _M_ptr;
			_M_ptr = __ref._M_ptr;
		}
		return *this;
	}
	// 成員函數(shù)模板（Member Function Templates）②
	// 如果可以從_Tp*轉(zhuǎn)換為_Tp1*，則可以從auto_ptr<_Tp>轉(zhuǎn)換為auto_ptr_ref<_Tp1>
	template <class _Tp1> operator auto_ptr_ref<_Tp1>() __STL_NOTHROW 
	{ return auto_ptr_ref<_Tp1>(this->release()); }
	// 成員函數(shù)模板（Member Function Templates）②
	// 如果可以從_Tp*轉(zhuǎn)換為_Tp1*，則可以從auto_ptr<_Tp>轉(zhuǎn)換為auto_ptr<_Tp1>
	template <class _Tp1> operator auto_ptr<_Tp1>() __STL_NOTHROW
	{ return auto_ptr<_Tp1>(this->release()); }
 
#endif /* auto ptr conversions && member templates */
};
 
__STL_END_NAMESPACE
 
#endif /* __SGI_STL_MEMORY */
 
// Local Variables:
// mode:C++
// End:

public:
	// 從auto_ptr_ref<_Tp>構(gòu)造auto_ptr<_Tp>
	auto_ptr(auto_ptr_ref<_Tp> __ref) __STL_NOTHROW
		: _M_ptr(__ref._M_ptr) {}
	// 從auto_ptr_ref<_Tp>對(duì)auto_ptr<_Tp>進(jìn)行賦值操作。
	// 注意這里是普通傳參，沒有引用④
	auto_ptr& operator=(auto_ptr_ref<_Tp> __ref) __STL_NOTHROW {
		if (__ref._M_ptr != this->get()) {
			delete _M_ptr;
			_M_ptr = __ref._M_ptr;
		}
		return *this;
	}

	template <class _Tp1> operator auto_ptr_ref<_Tp1>() __STL_NOTHROW 
	{ return auto_ptr_ref<_Tp1>(this->release()); }