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Viewing changes to libs/boost-lib/boost/smart_ptr/detail/atomic_count_pthreads.hpp

  • Committer: Bazaar Package Importer
  • Author(s): Alessio Treglia
  • Date: 2010-11-04 11:46:25 UTC
  • mto: This revision was merged to the branch mainline in revision 8.
  • Revision ID: james.westby@ubuntu.com-20101104114625-8xfdhvhpsm51i0nu
Tags: upstream-0.8.0
Import upstream version 0.8.0

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libs/boost-lib/boost/smart_ptr/detail/atomic_count_pthreads.hpp
 
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#ifndef BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_PTHREADS_HPP_INCLUDED
 
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#define BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_PTHREADS_HPP_INCLUDED
 
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//
 
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//  boost/detail/atomic_count_pthreads.hpp
 
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//
 
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//  Copyright (c) 2001, 2002 Peter Dimov and Multi Media Ltd.
 
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//
 
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// Distributed under the Boost Software License, Version 1.0. (See
 
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// accompanying file LICENSE_1_0.txt or copy at
 
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// http://www.boost.org/LICENSE_1_0.txt)
 
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//
 
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#include <pthread.h>
 
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//
 
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//  The generic pthread_mutex-based implementation sometimes leads to
 
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//    inefficiencies. Example: a class with two atomic_count members
 
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//    can get away with a single mutex.
 
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//
 
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//  Users can detect this situation by checking BOOST_AC_USE_PTHREADS.
 
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//
 
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namespace boost
 
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{
 
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namespace detail
 
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{
 
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class atomic_count
 
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{
 
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private:
 
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    class scoped_lock
 
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    {
 
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    public:
 
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        scoped_lock(pthread_mutex_t & m): m_(m)
 
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        {
 
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            pthread_mutex_lock(&m_);
 
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        }
 
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        ~scoped_lock()
 
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        {
 
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            pthread_mutex_unlock(&m_);
 
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        }
 
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    private:
 
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        pthread_mutex_t & m_;
 
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    };
 
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public:
 
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    explicit atomic_count(long v): value_(v)
 
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    {
 
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        pthread_mutex_init(&mutex_, 0);
 
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    }
 
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    ~atomic_count()
 
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    {
 
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        pthread_mutex_destroy(&mutex_);
 
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    }
 
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    long operator++()
 
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    {
 
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        scoped_lock lock(mutex_);
 
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        return ++value_;
 
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    }
 
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    long operator--()
 
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    {
 
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        scoped_lock lock(mutex_);
 
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        return --value_;
 
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    }
 
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    operator long() const
 
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    {
 
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        scoped_lock lock(mutex_);
 
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        return value_;
 
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    }
 
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private:
 
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    atomic_count(atomic_count const &);
 
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    atomic_count & operator=(atomic_count const &);
 
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    mutable pthread_mutex_t mutex_;
 
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    long value_;
 
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};
 
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} // namespace detail
 
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} // namespace boost
 
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#endif // #ifndef BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_PTHREADS_HPP_INCLUDED