#ifndef BOOST_DETAIL_SP_COUNTED_BASE_CW_PPC_HPP_INCLUDED

#define BOOST_DETAIL_SP_COUNTED_BASE_CW_PPC_HPP_INCLUDED

// MS compatible compilers support #pragma once

#if defined(_MSC_VER) && (_MSC_VER >= 1020)

# pragma once

#endif

//

//  detail/sp_counted_base_cw_ppc.hpp - CodeWarrior on PowerPC

//

//  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.

//  Copyright 2004-2005 Peter Dimov

//

//  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)

//

//

//  Lock-free algorithm by Alexander Terekhov

//

//  Thanks to Ben Hitchings for the #weak + (#shared != 0)

//  formulation

//

#include <typeinfo>

namespace boost

{

namespace detail

{

inline void atomic_increment( register long * pw )

{

    register int a;

    asm

    {

loop:

    lwarx   a, 0, pw

    addi    a, a, 1

    stwcx.  a, 0, pw

    bne-    loop

    }

}

inline long atomic_decrement( register long * pw )

{

    register int a;

    asm

    {

    sync

loop:

    lwarx   a, 0, pw

    addi    a, a, -1

    stwcx.  a, 0, pw

    bne-    loop

    isync

    }

    return a;

}

inline long atomic_conditional_increment( register long * pw )

{

    register int a;

    asm

    {

loop:

    lwarx   a, 0, pw

    cmpwi   a, 0

    beq     store

    addi    a, a, 1

store:

    stwcx.  a, 0, pw

    bne-    loop

    }

    return a;

}

class sp_counted_base

{

private:

    sp_counted_base( sp_counted_base const & );

    sp_counted_base & operator= ( sp_counted_base const & );

    long use_count_;        // #shared

    long weak_count_;       // #weak + (#shared != 0)

public:

    sp_counted_base(): use_count_( 1 ), weak_count_( 1 )

    {

    }

    virtual ~sp_counted_base() // nothrow

    {

    }

    // dispose() is called when use_count_ drops to zero, to release

    // the resources managed by *this.

    virtual void dispose() = 0; // nothrow

    // destroy() is called when weak_count_ drops to zero.

    virtual void destroy() // nothrow

    {

        delete this;

    }

    virtual void * get_deleter( std::type_info const & ti ) = 0;

    void add_ref_copy()

    {

        atomic_increment( &use_count_ );

    }

    bool add_ref_lock() // true on success

    {

        return atomic_conditional_increment( &use_count_ ) != 0;

    }

    void release() // nothrow

    {

        if( atomic_decrement( &use_count_ ) == 0 )

        {

            dispose();

            weak_release();

        }

    }

    void weak_add_ref() // nothrow

    {

        atomic_increment( &weak_count_ );

    }

    void weak_release() // nothrow

    {

        if( atomic_decrement( &weak_count_ ) == 0 )

        {

            destroy();

        }

    }

    long use_count() const // nothrow

    {

        return static_cast<long const volatile &>( use_count_ );

    }

};

} // namespace detail

} // namespace boost

#endif  // #ifndef BOOST_DETAIL_SP_COUNTED_BASE_CW_PPC_HPP_INCLUDED