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
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
/*
* Copyright (C) 2001-2006 Jacek Sieka, arnetheduck on gmail point com
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#if !defined(CRITICAL_SECTION_H)
#define CRITICAL_SECTION_H
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#include "Thread.h"
class CriticalSection
{
#ifdef _WIN32
public:
void enter() throw() {
EnterCriticalSection(&cs);
dcdrun(counter++);
}
void leave() throw() {
dcassert(--counter >= 0);
LeaveCriticalSection(&cs);
}
CriticalSection() throw() {
dcdrun(counter = 0;);
InitializeCriticalSection(&cs);
}
~CriticalSection() throw() {
dcassert(counter==0);
DeleteCriticalSection(&cs);
}
private:
dcdrun(long counter;);
CRITICAL_SECTION cs;
#else
public:
CriticalSection() throw() {
pthread_mutexattr_init(&ma);
pthread_mutexattr_settype(&ma, PTHREAD_MUTEX_RECURSIVE);
pthread_mutex_init(&mtx, &ma);
}
~CriticalSection() throw() {
pthread_mutex_destroy(&mtx);
pthread_mutexattr_destroy(&ma);
}
void enter() throw() { pthread_mutex_lock(&mtx); }
void leave() throw() { pthread_mutex_unlock(&mtx); }
pthread_mutex_t& getMutex() { return mtx; }
private:
pthread_mutex_t mtx;
pthread_mutexattr_t ma;
#endif
CriticalSection(const CriticalSection&);
CriticalSection& operator=(const CriticalSection&);
};
/**
* A fast, non-recursive and unfair implementation of the Critical Section.
* It is meant to be used in situations where the risk for lock conflict is very low,
* i e locks that are held for a very short time. The lock is _not_ recursive, i e if
* the same thread will try to grab the lock it'll hang in a never-ending loop. The lock
* is not fair, i e the first to try to enter a locked lock is not guaranteed to be the
* first to get it when it's freed...
*/
class FastCriticalSection {
public:
#ifdef _WIN32
FastCriticalSection() : state(0) { }
void enter() {
while(Thread::safeExchange(state, 1) == 1) {
Thread::yield();
}
}
void leave() {
Thread::safeDec(state);
}
private:
volatile long state;
#else
// We have to use a pthread (nonrecursive) mutex, didn't find any test_and_set on linux...
FastCriticalSection() {
static pthread_mutex_t fastmtx = PTHREAD_MUTEX_INITIALIZER;
mtx = fastmtx;
}
~FastCriticalSection() { pthread_mutex_destroy(&mtx); }
void enter() { pthread_mutex_lock(&mtx); }
void leave() { pthread_mutex_unlock(&mtx); }
private:
pthread_mutex_t mtx;
#endif
};
template<class T>
class LockBase {
public:
LockBase(T& aCs) throw() : cs(aCs) { cs.enter(); }
~LockBase() throw() { cs.leave(); }
private:
LockBase& operator=(const LockBase&);
T& cs;
};
typedef LockBase<CriticalSection> Lock;
typedef LockBase<FastCriticalSection> FastLock;
template<class T = CriticalSection>
class RWLock
{
public:
RWLock() throw() : cs(), readers(0) { }
~RWLock() throw() { dcassert(readers==0); }
void enterRead() throw() {
cs.enter();
readers++;
dcassert(readers < 100);
cs.leave();
}
void leaveRead() throw() {
dcassert(readers > 0);
Thread::safeDec(readers);
}
void enterWrite() throw() {
cs.enter();
while(readers > 0) {
Thread::yield();
}
}
void leaveWrite() {
cs.leave();
}
private:
T cs;
volatile long readers;
};
template<class T = CriticalSection>
class RLock {
public:
RLock(RWLock<T>& aRwl) throw() : rwl(aRwl) { rwl.enterRead(); }
~RLock() throw() { rwl.leaveRead(); }
private:
RLock& operator=(const RLock&);
RWLock<T>& rwl;
};
template<class T = CriticalSection>
class WLock {
public:
WLock(RWLock<T>& aRwl) throw() : rwl(aRwl) { rwl.enterWrite(); }
~WLock() throw() { rwl.leaveWrite(); }
private:
WLock& operator=(const WLock&);
RWLock<T>& rwl;
};
#endif // !defined(CRITICAL_SECTION_H)
|
