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Jeff Thompsonf7d49942013-08-01 16:47:40 -07001#ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_W32_HPP_INCLUDED
2#define BOOST_SMART_PTR_DETAIL_SPINLOCK_W32_HPP_INCLUDED
3
4// MS compatible compilers support #pragma once
5
6#if defined(_MSC_VER) && (_MSC_VER >= 1020)
7# pragma once
8#endif
9
10//
11// Copyright (c) 2008 Peter Dimov
12//
13// Distributed under the Boost Software License, Version 1.0.
14// See accompanying file LICENSE_1_0.txt or copy at
15// http://www.boost.org/LICENSE_1_0.txt)
16//
17
18#include <boost/detail/interlocked.hpp>
19#include <boost/smart_ptr/detail/yield_k.hpp>
20
21// BOOST_COMPILER_FENCE
22
23#if defined(__INTEL_COMPILER)
24
25#define BOOST_COMPILER_FENCE __memory_barrier();
26
27#elif defined( _MSC_VER ) && _MSC_VER >= 1310
28
29extern "C" void _ReadWriteBarrier();
30#pragma intrinsic( _ReadWriteBarrier )
31
32#define BOOST_COMPILER_FENCE _ReadWriteBarrier();
33
34#elif defined(__GNUC__)
35
36#define BOOST_COMPILER_FENCE __asm__ __volatile__( "" : : : "memory" );
37
38#else
39
40#define BOOST_COMPILER_FENCE
41
42#endif
43
44//
45
46namespace ndnboost
47{
48
49namespace detail
50{
51
52class spinlock
53{
54public:
55
56 long v_;
57
58public:
59
60 bool try_lock()
61 {
62 long r = BOOST_INTERLOCKED_EXCHANGE( &v_, 1 );
63
64 BOOST_COMPILER_FENCE
65
66 return r == 0;
67 }
68
69 void lock()
70 {
71 for( unsigned k = 0; !try_lock(); ++k )
72 {
73 ndnboost::detail::yield( k );
74 }
75 }
76
77 void unlock()
78 {
79 BOOST_COMPILER_FENCE
80 *const_cast< long volatile* >( &v_ ) = 0;
81 }
82
83public:
84
85 class scoped_lock
86 {
87 private:
88
89 spinlock & sp_;
90
91 scoped_lock( scoped_lock const & );
92 scoped_lock & operator=( scoped_lock const & );
93
94 public:
95
96 explicit scoped_lock( spinlock & sp ): sp_( sp )
97 {
98 sp.lock();
99 }
100
101 ~scoped_lock()
102 {
103 sp_.unlock();
104 }
105 };
106};
107
108} // namespace detail
109} // namespace ndnboost
110
111#define BOOST_DETAIL_SPINLOCK_INIT {0}
112
113#endif // #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_W32_HPP_INCLUDED