114 lines
2.0 KiB
C++
114 lines
2.0 KiB
C++
#ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_W32_HPP_INCLUDED
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#define BOOST_SMART_PTR_DETAIL_SPINLOCK_W32_HPP_INCLUDED
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// MS compatible compilers support #pragma once
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#if defined(_MSC_VER) && (_MSC_VER >= 1020)
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# pragma once
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#endif
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//
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// Copyright (c) 2008 Peter Dimov
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//
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// Distributed under the Boost Software License, Version 1.0.
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// See 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 <boost/detail/interlocked.hpp>
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#include <boost/smart_ptr/detail/yield_k.hpp>
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// BOOST_COMPILER_FENCE
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#if defined(__INTEL_COMPILER)
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#define BOOST_COMPILER_FENCE __memory_barrier();
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#elif defined( _MSC_VER ) && _MSC_VER >= 1310
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extern "C" void _ReadWriteBarrier();
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#pragma intrinsic( _ReadWriteBarrier )
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#define BOOST_COMPILER_FENCE _ReadWriteBarrier();
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#elif defined(__GNUC__)
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#define BOOST_COMPILER_FENCE __asm__ __volatile__( "" : : : "memory" );
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#else
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#define BOOST_COMPILER_FENCE
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#endif
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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 spinlock
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{
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public:
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long v_;
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public:
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bool try_lock()
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{
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long r = BOOST_INTERLOCKED_EXCHANGE( &v_, 1 );
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BOOST_COMPILER_FENCE
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return r == 0;
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}
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void lock()
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{
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for( unsigned k = 0; !try_lock(); ++k )
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{
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boost::detail::yield( k );
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}
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}
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void unlock()
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{
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BOOST_COMPILER_FENCE
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*const_cast< long volatile* >( &v_ ) = 0;
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}
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public:
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class scoped_lock
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{
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private:
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spinlock & sp_;
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scoped_lock( scoped_lock const & );
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scoped_lock & operator=( scoped_lock const & );
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public:
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explicit scoped_lock( spinlock & sp ): sp_( sp )
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{
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sp.lock();
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}
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~scoped_lock()
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{
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sp_.unlock();
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}
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};
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};
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} // namespace detail
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} // namespace boost
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#define BOOST_DETAIL_SPINLOCK_INIT {0}
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#endif // #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_W32_HPP_INCLUDED
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