1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
|
#ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_VACPP_PPC_HPP_INCLUDED
#define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_VACPP_PPC_HPP_INCLUDED
//
// detail/sp_counted_base_vacpp_ppc.hpp - xlC(vacpp) on POWER
// based on: detail/sp_counted_base_w32.hpp
//
// Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
// Copyright 2004-2005 Peter Dimov
// Copyright 2006 Michael van der Westhuizen
// Copyright 2012 IBM Corp.
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
//
// Lock-free algorithm by Alexander Terekhov
//
// Thanks to Ben Hitchings for the #weak + (#shared != 0)
// formulation
//
#include <cutl/details/boost/detail/sp_typeinfo.hpp>
extern "builtin" void __lwsync(void);
extern "builtin" void __isync(void);
extern "builtin" int __fetch_and_add(volatile int* addr, int val);
extern "builtin" int __compare_and_swap(volatile int*, int*, int);
namespace cutl_details_boost
{
namespace detail
{
inline void atomic_increment( int *pw )
{
// ++*pw;
__lwsync();
__fetch_and_add(pw, 1);
__isync();
}
inline int atomic_decrement( int *pw )
{
// return --*pw;
__lwsync();
int originalValue = __fetch_and_add(pw, -1);
__isync();
return (originalValue - 1);
}
inline int atomic_conditional_increment( int *pw )
{
// if( *pw != 0 ) ++*pw;
// return *pw;
__lwsync();
int v = *const_cast<volatile int*>(pw);
for (;;)
// loop until state is known
{
if (v == 0) return 0;
if (__compare_and_swap(pw, &v, v + 1))
{
__isync(); return (v + 1);
}
}
}
class sp_counted_base
{
private:
sp_counted_base( sp_counted_base const & );
sp_counted_base & operator= ( sp_counted_base const & );
int use_count_; // #shared
int weak_count_; // #weak + (#shared != 0)
char pad[64] __attribute__((__aligned__(64)));
// pad to prevent false sharing
public:
sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
{
}
virtual ~sp_counted_base() // nothrow
{
}
// dispose() is called when use_count_ drops to zero, to release
// the resources managed by *this.
virtual void dispose() = 0; // nothrow
// destroy() is called when weak_count_ drops to zero.
virtual void destroy() // nothrow
{
delete this;
}
virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
virtual void * get_untyped_deleter() = 0;
void add_ref_copy()
{
atomic_increment( &use_count_ );
}
bool add_ref_lock() // true on success
{
return atomic_conditional_increment( &use_count_ ) != 0;
}
void release() // nothrow
{
if( atomic_decrement( &use_count_ ) == 0 )
{
dispose();
weak_release();
}
}
void weak_add_ref() // nothrow
{
atomic_increment( &weak_count_ );
}
void weak_release() // nothrow
{
if( atomic_decrement( &weak_count_ ) == 0 )
{
destroy();
}
}
long use_count() const // nothrow
{
return *const_cast<volatile int*>(&use_count_);
}
};
} // namespace detail
} // namespace cutl_details_boost
#endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_VACPP_PPC_HPP_INCLUDED
|
