#ifndef BOOST_DETAIL_SP_COUNTED_BASE_GCC_SPARC_HPP_INCLUDED
#define BOOST_DETAIL_SP_COUNTED_BASE_GCC_SPARC_HPP_INCLUDED

// MS compatible compilers support #pragma once

#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif

//  detail/sp_counted_base_gcc_sparc.hpp - g++ on Sparc V9+
//
//  Copyright (c) 2006 Piotr Wyderski
//  Based on the framework by 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)

#include <typeinfo>

namespace boost
{

namespace detail
{

inline long compare_exchange(long* v, const long c, const long n) {

    long r;

#ifdef __arch64__

    // UltraSparc 64-bit variant

    __asm__ __volatile__("casx [%2], %3, %0         \t\n" \
                         "                          \t\n"
                         : "=&r"(r), "=m"(*v)
                         : "r"(v), "r"(c), "0"(n), "m"(*v)
                         :);
#else

    // Legacy 32-bit variant

    __asm__ __volatile__("cas [%2], %3, %0          \t\n" \
                         "                          \t\n"
                         : "=&r"(r), "=m"(*v)
                         : "r"(v), "r"(c), "0"(n), "m"(*v)
                         :);
#endif

    return r;
}

inline long atomic_exchange_and_add(long * pw, long dv )
{
    // long r = *pw;
    // *pw += dv;
    // return r;

    for(;;) {

        const long r = *pw;

        if (__builtin_expect((compare_exchange(pw, r, r + dv) == r), 1))
            return r;
    }
}

inline void atomic_increment( long * pw )
{
    atomic_exchange_and_add( pw, 1L );
}

inline long atomic_conditional_increment( long * pw )
{
    // long r = *pw;
    // if( r != 0 ) ++*pw;
    // return r;

    for(;;) {

        const long r = *pw;

        if (__builtin_expect((r == 0L), 0))
            return r;

        if (__builtin_expect((compare_exchange(pw, r, r + 1L) == r), 1))
            return r;
    }    
}

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_( 1L ), weak_count_( 1L )
    {
    }

    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_ ) != 0L;
    }

    void release() // nothrow
    {
        if( atomic_exchange_and_add( &use_count_, -1L ) == 1L )
        {
            dispose();
            weak_release();
        }
    }

    void weak_add_ref() // nothrow
    {
        atomic_increment( &weak_count_ );
    }

    void weak_release() // nothrow
    {
        if( atomic_exchange_and_add( &weak_count_, -1L ) == 1L )
        {
            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_GCC_SPARC_HPP_INCLUDED