CMake/VMSbuild/cmsys/auto_ptr.hxx

204 lines
5.7 KiB
C++

/*=========================================================================
Program: KWSys - Kitware System Library
Module: $RCSfile$
Copyright (c) Kitware, Inc., Insight Consortium. All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notices for more information.
=========================================================================*/
#ifndef cmsys_auto_ptr_hxx
#define cmsys_auto_ptr_hxx
#include <cmsys/Configure.hxx>
// The HP compiler and VS6 cannot handle the conversions necessary to use
// auto_ptr_ref to pass an auto_ptr returned from one function
// directly to another function as in use_auto_ptr(get_auto_ptr()).
// We instead use const_cast to achieve the syntax on those platforms.
// We do not use const_cast on other platforms to maintain the C++
// standard design and guarantee that if an auto_ptr is bound
// to a reference-to-const then ownership will be maintained.
#if defined(__HP_aCC) || (defined(_MSC_VER) && _MSC_VER <= 1200)
# define cmsys_AUTO_PTR_REF 0
# define cmsys_AUTO_PTR_CONST const
# define cmsys_AUTO_PTR_CAST(a) cast(a)
#else
# define cmsys_AUTO_PTR_REF 1
# define cmsys_AUTO_PTR_CONST
# define cmsys_AUTO_PTR_CAST(a) a
#endif
namespace cmsys
{
template <class X> class auto_ptr;
#if cmsys_AUTO_PTR_REF
namespace detail
{
// The auto_ptr_ref template is supposed to be a private member of
// auto_ptr but Borland 5.8 cannot handle it. Instead put it in
// a private namespace.
template <class Y> struct auto_ptr_ref
{
Y* p_;
// The extra constructor argument prevents implicit conversion to
// auto_ptr_ref from auto_ptr through the constructor. Normally
// this should be done with the explicit keyword but Borland 5.x
// generates code in the conversion operator to call itself
// infinately.
auto_ptr_ref(Y* p, int): p_(p) {}
};
}
#endif
/** C++98 Standard Section 20.4.5 - Template class auto_ptr. */
template <class X>
class auto_ptr
{
#if !cmsys_AUTO_PTR_REF
template <typename Y>
static inline auto_ptr<Y>& cast(auto_ptr<Y> const& a)
{ return const_cast<auto_ptr<Y>&>(a); }
#endif
/** The pointer to the object held. */
X* x_;
public:
/** The type of object held by the auto_ptr. */
typedef X element_type;
/** Construct from an auto_ptr holding a compatible object. This
transfers ownership to the newly constructed auto_ptr. */
template <class Y>
auto_ptr(auto_ptr<Y> cmsys_AUTO_PTR_CONST& a) throw():
x_(cmsys_AUTO_PTR_CAST(a).release())
{
}
/** Assign from an auto_ptr holding a compatible object. This
transfers ownership to the left-hand-side of the assignment. */
template <class Y>
auto_ptr& operator=(auto_ptr<Y> cmsys_AUTO_PTR_CONST& a) throw()
{
this->reset(cmsys_AUTO_PTR_CAST(a).release());
return *this;
}
/**
* Explicitly construct from a raw pointer. This is typically
* called with the result of operator new. For example:
*
* auto_ptr<X> ptr(new X());
*/
explicit auto_ptr(X* p=0) throw(): x_(p)
{
}
/** Construct from another auto_ptr holding an object of the same
type. This transfers ownership to the newly constructed
auto_ptr. */
auto_ptr(auto_ptr cmsys_AUTO_PTR_CONST& a) throw():
x_(cmsys_AUTO_PTR_CAST(a).release())
{
}
/** Assign from another auto_ptr holding an object of the same type.
This transfers ownership to the newly constructed auto_ptr. */
auto_ptr& operator=(auto_ptr cmsys_AUTO_PTR_CONST& a) throw()
{
this->reset(cmsys_AUTO_PTR_CAST(a).release());
return *this;
}
/** Destruct and delete the object held. */
~auto_ptr() throw()
{
// Assume object destructor is nothrow.
delete this->x_;
}
/** Dereference and return a reference to the object held. */
X& operator*() const throw()
{
return *this->x_;
}
/** Return a pointer to the object held. */
X* operator->() const throw()
{
return this->x_;
}
/** Return a pointer to the object held. */
X* get() const throw()
{
return this->x_;
}
/** Return a pointer to the object held and reset to hold no object.
This transfers ownership to the caller. */
X* release() throw()
{
X* x = this->x_;
this->x_ = 0;
return x;
}
/** Assume ownership of the given object. The object previously
held is deleted. */
void reset(X* p=0) throw()
{
if(this->x_ != p)
{
// Assume object destructor is nothrow.
delete this->x_;
this->x_ = p;
}
}
/** Convert to an auto_ptr holding an object of a compatible type.
This transfers ownership to the returned auto_ptr. */
template <class Y> operator auto_ptr<Y>() throw()
{
return auto_ptr<Y>(this->release());
}
#if cmsys_AUTO_PTR_REF
/** Construct from an auto_ptr_ref. This is used when the
constructor argument is a call to a function returning an
auto_ptr. */
auto_ptr(detail::auto_ptr_ref<X> r) throw(): x_(r.p_)
{
}
/** Assign from an auto_ptr_ref. This is used when a function
returning an auto_ptr is passed on the right-hand-side of an
assignment. */
auto_ptr& operator=(detail::auto_ptr_ref<X> r) throw()
{
this->reset(r.p_);
return *this;
}
/** Convert to an auto_ptr_ref. This is used when a function
returning an auto_ptr is the argument to the constructor of
another auto_ptr. */
template <class Y> operator detail::auto_ptr_ref<Y>() throw()
{
return detail::auto_ptr_ref<Y>(this->release(), 1);
}
#endif
};
} // namespace cmsys
#endif