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1 | #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/smart_ptr/detail/sp_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 | ||
29 | extern "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 | ||
46 | namespace boost | |
47 | { | |
48 | ||
49 | namespace detail | |
50 | { | |
51 | ||
52 | class spinlock | |
53 | { | |
54 | public: | |
55 | ||
56 | long v_; | |
57 | ||
58 | public: | |
59 | ||
60 | bool try_lock() | |
61 | { | |
62 | long r = BOOST_SP_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 | boost::detail::yield( k ); | |
74 | } | |
75 | } | |
76 | ||
77 | void unlock() | |
78 | { | |
79 | BOOST_COMPILER_FENCE | |
80 | *const_cast< long volatile* >( &v_ ) = 0; | |
81 | } | |
82 | ||
83 | public: | |
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 boost | |
110 | ||
111 | #define BOOST_DETAIL_SPINLOCK_INIT {0} | |
112 | ||
113 | #endif // #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_W32_HPP_INCLUDED |