auto_ptr 源码

template <typename _Tp>
class auto_ptr
{
private:
_Tp *m_ptr;
public:
typedef _Tp elementType;

// object life cycle
explicit auto_ptr(elementType *p) throw():m_ptr(p)
{
}

auto_ptr(auto_ptr &a) throw():m_ptr(a.release())
{
}

template <typename _Tp1>
auto_ptr(auto_ptr<_Tp1> &a) throw() : m_ptr(a.release())
{
}

auto_ptr& operator= (auto_ptr& a) throw()
{
reset(a.release());
return *this;
}

template <typename _Tp1>
auto_ptr& operator=(auto_ptr<_Tp1> &a) throw()
{
reset(a.release());
return *this;
}

~auto_ptr()
{
delete m_ptr;
}

// operator override
elementType& operator*() const throw()
{
assert(m_ptr != 0);
return *m_ptr;
}

elementType* operator->() const throw()
{
assert(m_ptr != 0);
return m_ptr;
}

// helper
elementType* get() const throw()
{
return m_ptr;
}

elementType* release() throw()
{
elementType *tmp = m_ptr;
m_ptr = 0;
return tmp;
}

void reset(elementType *p = 0) throw()
{
if (p != m_ptr)
{
delete m_ptr;
m_ptr = p;
}
}
};