forked from boostorg/smart_ptr
80 lines
1.5 KiB
C++
80 lines
1.5 KiB
C++
#ifndef BOOST_DETAIL_LWM_LINUX_HPP_INCLUDED
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#define BOOST_DETAIL_LWM_LINUX_HPP_INCLUDED
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#if _MSC_VER >= 1020
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#pragma once
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#endif
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//
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// boost/detail/lwm_linux.hpp
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//
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// Copyright (c) 2002 Peter Dimov and Multi Media Ltd.
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//
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// Permission to copy, use, modify, sell and distribute this software
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// is granted provided this copyright notice appears in all copies.
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// This software is provided "as is" without express or implied
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// warranty, and with no claim as to its suitability for any purpose.
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//
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#include <asm/atomic.h>
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#include <sched.h>
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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 lightweight_mutex
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{
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private:
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atomic_t a_;
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lightweight_mutex(lightweight_mutex const &);
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lightweight_mutex & operator=(lightweight_mutex const &);
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public:
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lightweight_mutex()
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{
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atomic_t a = ATOMIC_INIT(1);
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a_ = a;
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}
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class scoped_lock;
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friend class scoped_lock;
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class scoped_lock
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{
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private:
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lightweight_mutex & m_;
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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(lightweight_mutex & m): m_(m)
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{
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while( !atomic_dec_and_test(&m_.a_) )
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{
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atomic_inc(&m_.a_);
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sched_yield();
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}
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}
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~scoped_lock()
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{
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atomic_inc(&m_.a_);
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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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#endif // #ifndef BOOST_DETAIL_LWM_WIN32_HPP_INCLUDED
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