static_move_ptr.hpp

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// (C) Copyright Thorsten Ottosen 2005.
// (C) Copyright Jonathan Turkanis 2004.
// (C) Copyright Daniel Wallin 2004.
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)

// Implementation of the move_ptr from the "Move Proposal" 
// (http://std.dkuug.dk/jtc1/sc22/wg21/docs/papers/2002/n1377.htm) 
// enhanced to support custom deleters and safe boolean conversions.
//
// The implementation is based on an implementation by Daniel Wallin, at
// "http://aspn.activestate.com/ASPN/Mail/Message/Attachments/boost/
// [e-mail]/move_ptr.hpp". The current was adapted 
// by Jonathan Turkanis to incorporating ideas of Howard Hinnant and 
// Rani Sharoni. 

#ifndef BOOST_STATIC_MOVE_PTR_HPP_INCLUDED
#define BOOST_STATIC_MOVE_PTR_HPP_INCLUDED

#include <boost/config.hpp> // Member template friends, put size_t in std.
#include <cstddef>          // size_t
#include <boost/compressed_pair.hpp> 
#include <boost/ptr_container/detail/default_deleter.hpp>       
#include <boost/ptr_container/detail/is_convertible.hpp>       
#include <boost/ptr_container/detail/move.hpp>       
#include <boost/static_assert.hpp>
#include <boost/type_traits/add_reference.hpp>
#include <boost/type_traits/is_array.hpp>

#if defined(BOOST_MSVC)
#pragma warning(push)
#pragma warning(disable:4521)        // Multiple copy constuctors.
#endif

namespace boost { namespace ptr_container_detail {

    
template< typename T, 
          typename Deleter = 
              move_ptrs::default_deleter<T> >
class static_move_ptr 
{
public:

    typedef typename remove_bounds<T>::type             element_type;
    typedef Deleter                                     deleter_type;

private:
    
    struct safe_bool_helper { int x; };
    typedef int safe_bool_helper::* safe_bool;
    typedef boost::compressed_pair<element_type*, Deleter> impl_type;

public:
    typedef typename impl_type::second_reference        deleter_reference;
    typedef typename impl_type::second_const_reference  deleter_const_reference;

        // Constructors

    static_move_ptr() : impl_(0) { }

    static_move_ptr(const static_move_ptr& p)
        : impl_(p.get(), p.get_deleter())    
        { 
            const_cast<static_move_ptr&>(p).release();
        }

#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))    
    static_move_ptr( const move_ptrs::move_source<static_move_ptr<T,Deleter> >& src )
#else
    static_move_ptr( const move_ptrs::move_source<static_move_ptr>& src )
#endif    
            : impl_(src.ptr().get(), src.ptr().get_deleter())
            {
                src.ptr().release();
            }
    
    template<typename TT>
    explicit static_move_ptr(TT* tt) 
        : impl_(tt, Deleter()) 
        { }

        // Destructor

    ~static_move_ptr() { if (ptr()) get_deleter()(ptr()); }

        // Assignment

    static_move_ptr& operator=(static_move_ptr rhs)
        {
            rhs.swap(*this);
            return *this;
        }

        // Smart pointer interface

    element_type* get() const { return ptr(); }

    element_type& operator*() 
        { 
            /*BOOST_STATIC_ASSERT(!is_array);*/ return *ptr(); 
        }

    const element_type& operator*() const 
        { 
            /*BOOST_STATIC_ASSERT(!is_array);*/ return *ptr(); 
        }

    element_type* operator->()  
        { 
            /*BOOST_STATIC_ASSERT(!is_array);*/ return ptr(); 
        }    

    const element_type* operator->() const 
        { 
            /*BOOST_STATIC_ASSERT(!is_array);*/ return ptr(); 
        }    


    element_type* release()
        {
            element_type* result = ptr();
            ptr() = 0;
            return result;
        }

    void reset()
        {
            if (ptr()) get_deleter()(ptr());
            ptr() = 0;
        }

    template<typename TT>
    void reset(TT* tt) 
        {
            static_move_ptr(tt).swap(*this);
        }

    template<typename TT, typename DD>
    void reset(TT* tt, DD dd) 
        {
            static_move_ptr(tt, dd).swap(*this);
        }

    operator safe_bool() const { return ptr() ? &safe_bool_helper::x : 0; }

    void swap(static_move_ptr& p) { impl_.swap(p.impl_); }

    deleter_reference get_deleter() { return impl_.second(); }

    deleter_const_reference get_deleter() const { return impl_.second(); }
private:
    template<typename TT, typename DD>
    void check(const static_move_ptr<TT, DD>& ptr)
        {
            typedef move_ptrs::is_smart_ptr_convertible<TT, T> convertible;
            BOOST_STATIC_ASSERT(convertible::value);
        }   

#if defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING) || defined(BOOST_NO_SFINAE)
// give up on this behavior
#else 

    template<typename Ptr> struct cant_move_from_const;

    template<typename TT, typename DD> 
    struct cant_move_from_const< const static_move_ptr<TT, DD> > { 
        typedef typename static_move_ptr<TT, DD>::error type; 
    };

    template<typename Ptr> 
    static_move_ptr(Ptr&, typename cant_move_from_const<Ptr>::type = 0);


public:
    static_move_ptr(static_move_ptr&);

    
private:
    template<typename TT, typename DD>
    static_move_ptr( static_move_ptr<TT, DD>&,
                     typename 
                     move_ptrs::enable_if_convertible<
                         TT, T, static_move_ptr&
                     >::type::type* = 0 );

#endif // BOOST_NO_FUNCTION_TEMPLATE_ORDERING || BOOST_NO_SFINAE

//#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
//    template<typename TT, typename DD>
//    friend class static_move_ptr;
//#else
    public:
//#endif
    typename impl_type::first_reference 
    ptr() { return impl_.first(); } 

    typename impl_type::first_const_reference 
    ptr() const { return impl_.first(); }

    impl_type impl_;
};

} // namespace ptr_container_detail
} // End namespace boost.

#if defined(BOOST_MSVC)
#pragma warning(pop) // #pragma warning(disable:4251)
#endif

#endif      // #ifndef BOOST_STATIC_MOVE_PTR_HPP_INCLUDED