#ifndef BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_PTHREADS_HPP_INCLUDED

#define BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_PTHREADS_HPP_INCLUDED

//

//  boost/detail/atomic_count_pthreads.hpp

//

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

//

// 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 <pthread.h>

//

//  The generic pthread_mutex-based implementation sometimes leads to

//    inefficiencies. Example: a class with two atomic_count members

//    can get away with a single mutex.

//

//  Users can detect this situation by checking BOOST_AC_USE_PTHREADS.

//

namespace boost

{

namespace detail

{

class atomic_count

{

private:

    class scoped_lock

    {

    public:

        scoped_lock(pthread_mutex_t & m): m_(m)

        {

            pthread_mutex_lock(&m_);

        }

        ~scoped_lock()

        {

            pthread_mutex_unlock(&m_);

        }

    private:

        pthread_mutex_t & m_;

    };

public:

    explicit atomic_count(long v): value_(v)

    {

        pthread_mutex_init(&mutex_, 0);

    }

    ~atomic_count()

    {

        pthread_mutex_destroy(&mutex_);

    }

    long operator++()

    {

        scoped_lock lock(mutex_);

        return ++value_;

    }

    long operator--()

    {

        scoped_lock lock(mutex_);

        return --value_;

    }

    operator long() const

    {

        scoped_lock lock(mutex_);

        return value_;

    }

private:

    atomic_count(atomic_count const &);

    atomic_count & operator=(atomic_count const &);

    mutable pthread_mutex_t mutex_;

    long value_;

};

} // namespace detail

} // namespace boost

#endif // #ifndef BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_PTHREADS_HPP_INCLUDED