smart_ptr/detail/spinlock_sync.hpp

0001 #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_SYNC_HPP_INCLUDED
0002 #define BOOST_SMART_PTR_DETAIL_SPINLOCK_SYNC_HPP_INCLUDED
0003
0004 // MS compatible compilers support #pragma once
0005
0006 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
0007 # pragma once
0008 #endif
0009
0010 //
0011 //  Copyright (c) 2008 Peter Dimov
0012 //
0013 //  Distributed under the Boost Software License, Version 1.0.
0014 //  See accompanying file LICENSE_1_0.txt or copy at
0015 //  http://www.boost.org/LICENSE_1_0.txt)
0016 //
0017
0018 #include <boost/smart_ptr/detail/yield_k.hpp>
0019
0020 #if defined( __ia64__ ) && defined( __INTEL_COMPILER )
0021 # include <ia64intrin.h>
0022 #endif
0023
0024 #if defined(BOOST_SP_REPORT_IMPLEMENTATION)
0025
0026 #include <boost/config/pragma_message.hpp>
0027 BOOST_PRAGMA_MESSAGE("Using __sync spinlock")
0028
0029 #endif
0030
0031 namespace boost
0032 {
0033
0034 namespace detail
0035 {
0036
0037 class spinlock
0038 {
0039 public:
0040
0041     unsigned char v_;
0042
0043 public:
0044
0045     bool try_lock()
0046     {
0047         int r = __sync_lock_test_and_set( &v_, 1 );
0048         return r == 0;
0049     }
0050
0051     void lock()
0052     {
0053         for( unsigned k = 0; !try_lock(); ++k )
0054         {
0055             boost::detail::yield( k );
0056         }
0057     }
0058
0059     void unlock()
0060     {
0061         __sync_lock_release( &v_ );
0062     }
0063
0064 public:
0065
0066     class scoped_lock
0067     {
0068     private:
0069
0070         spinlock & sp_;
0071
0072         scoped_lock( scoped_lock const & );
0073         scoped_lock & operator=( scoped_lock const & );
0074
0075     public:
0076
0077         explicit scoped_lock( spinlock & sp ): sp_( sp )
0078         {
0079             sp.lock();
0080         }
0081
0082         ~scoped_lock()
0083         {
0084             sp_.unlock();
0085         }
0086     };
0087 };
0088
0089 } // namespace detail
0090 } // namespace boost
0091
0092 #define BOOST_DETAIL_SPINLOCK_INIT {0}
0093
0094 #endif // #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_SYNC_HPP_INCLUDED