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1 | // Support for pointer abstractions -*- C++ -*- |
2 | ||
818ab71a | 3 | // Copyright (C) 2011-2016 Free Software Foundation, Inc. |
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4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free | |
6 | // software; you can redistribute it and/or modify it under the | |
7 | // terms of the GNU General Public License as published by the | |
8 | // Free Software Foundation; either version 3, or (at your option) | |
9 | // any later version. | |
10 | ||
11 | // This library is distributed in the hope that it will be useful, | |
12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | // GNU General Public License for more details. | |
15 | ||
16 | // Under Section 7 of GPL version 3, you are granted additional | |
17 | // permissions described in the GCC Runtime Library Exception, version | |
18 | // 3.1, as published by the Free Software Foundation. | |
19 | ||
20 | // You should have received a copy of the GNU General Public License and | |
21 | // a copy of the GCC Runtime Library Exception along with this program; | |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | // <http://www.gnu.org/licenses/>. | |
24 | ||
25 | #include <memory> | |
26 | ||
27 | namespace std _GLIBCXX_VISIBILITY(default) | |
28 | { | |
29 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
30 | ||
8535715d | 31 | bad_weak_ptr::~bad_weak_ptr() noexcept = default; |
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32 | |
33 | char const* | |
8535715d | 34 | bad_weak_ptr::what() const noexcept |
78aff336 | 35 | { return "bad_weak_ptr"; } |
e9599233 | 36 | |
be8de894 JW |
37 | #ifdef __GTHREADS |
38 | namespace | |
39 | { | |
40 | const unsigned char mask = 0xf; | |
41 | const unsigned char invalid = mask + 1; | |
42 | ||
43 | inline unsigned char key(const void* addr) | |
44 | { return _Hash_impl::hash(addr) & mask; } | |
45 | ||
46 | /* Returns different instances of __mutex depending on the passed address | |
47 | * in order to limit contention. | |
48 | */ | |
49 | __gnu_cxx::__mutex& | |
50 | get_mutex(unsigned char i) | |
51 | { | |
52 | static __gnu_cxx::__mutex m[mask + 1]; | |
53 | return m[i]; | |
54 | } | |
55 | } | |
56 | ||
57 | _Sp_locker::_Sp_locker(const void* p) | |
58 | { | |
59 | if (__gthread_active_p()) | |
60 | { | |
61 | _M_key1 = _M_key2 = key(p); | |
62 | get_mutex(_M_key1).lock(); | |
63 | } | |
64 | else | |
65 | _M_key1 = _M_key2 = invalid; | |
66 | } | |
67 | ||
68 | _Sp_locker::_Sp_locker(const void* p1, const void* p2) | |
69 | { | |
70 | if (__gthread_active_p()) | |
71 | { | |
72 | _M_key1 = key(p1); | |
73 | _M_key2 = key(p2); | |
74 | if (_M_key2 < _M_key1) | |
75 | get_mutex(_M_key2).lock(); | |
76 | get_mutex(_M_key1).lock(); | |
77 | if (_M_key2 > _M_key1) | |
78 | get_mutex(_M_key2).lock(); | |
79 | } | |
80 | else | |
81 | _M_key1 = _M_key2 = invalid; | |
82 | } | |
83 | ||
84 | _Sp_locker::~_Sp_locker() | |
85 | { | |
86 | if (_M_key1 != invalid) | |
87 | { | |
88 | get_mutex(_M_key1).unlock(); | |
89 | if (_M_key2 != _M_key1) | |
90 | get_mutex(_M_key2).unlock(); | |
91 | } | |
92 | } | |
93 | #endif | |
94 | ||
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95 | _GLIBCXX_END_NAMESPACE_VERSION |
96 | } // namespace |