1 // The MIT License (MIT)
2 //
3 // 	Copyright (c) 2015 Sergey Makeev, Vadim Slyusarev
4 //
5 // 	Permission is hereby granted, free of charge, to any person obtaining a copy
6 // 	of this software and associated documentation files (the "Software"), to deal
7 // 	in the Software without restriction, including without limitation the rights
8 // 	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 // 	copies of the Software, and to permit persons to whom the Software is
10 // 	furnished to do so, subject to the following conditions:
11 //
12 //  The above copyright notice and this permission notice shall be included in
13 // 	all copies or substantial portions of the Software.
14 //
15 // 	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 // 	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 // 	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 // 	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 // 	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 // 	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
21 // 	THE SOFTWARE.
22 
23 #pragma once
24 
25 #include <sys/time.h>
26 #include <sched.h>
27 #include <errno.h>
28 
29 
30 namespace MT
31 {
32 	//
33 	//
34 	//
35 	class Event
36 	{
37 		static const int NOT_SIGNALED = 0;
38 		static const int SIGNALED = 1;
39 
40 		pthread_mutex_t	mutex;
41 		pthread_cond_t	condition;
42 		AtomicInt val;
43 		EventReset::Type resetType;
44 		bool isInitialized;
45 
46 	private:
47 
48 		Event(const Event&) {}
49 		void operator=(const Event&) {}
50 
51 		void AutoResetIfNeed()
52 		{
53 			if (resetType == EventReset::MANUAL)
54 			{
55 				return;
56 			}
57 			Reset();
58 		}
59 
60 	public:
61 
62 		Event()
63 			: isInitialized(false)
64 		{
65 		}
66 
67 		Event(EventReset::Type resetType, bool initialState)
68 			: isInitialized(false)
69 		{
70 			Create(resetType, initialState);
71 		}
72 
73 		~Event()
74 		{
75 			if (isInitialized)
76 			{
77 				pthread_cond_destroy( &condition );
78 				pthread_mutex_destroy( &mutex );
79 			}
80 		}
81 
82 		void Create(EventReset::Type _resetType, bool initialState)
83 		{
84 			MT_ASSERT (!isInitialized, "Event already initialized");
85 
86 			resetType = _resetType;
87 
88 			pthread_mutex_init( &mutex, nullptr );
89 			pthread_cond_init( &condition, nullptr );
90 			val.Set(initialState ? SIGNALED : NOT_SIGNALED);
91 
92 			isInitialized = true;
93 		}
94 
95 		void Signal()
96 		{
97 			MT_ASSERT (isInitialized, "Event not initialized");
98 
99 			pthread_mutex_lock( &mutex );
100 
101 			val.Set(SIGNALED);
102 			pthread_cond_broadcast( &condition );
103 
104 			pthread_mutex_unlock( &mutex );
105 		}
106 
107 		void Reset()
108 		{
109 			MT_ASSERT (isInitialized, "Event not initialized");
110 
111 			val.Set(NOT_SIGNALED);
112 		}
113 
114 		bool Wait(uint32 milliseconds)
115 		{
116 			MT_ASSERT (isInitialized, "Event not initialized");
117 
118 			pthread_mutex_lock( &mutex );
119 
120 			// early exit if event already signaled
121 			if ( val.Get() != NOT_SIGNALED )
122 			{
123 				AutoResetIfNeed();
124 				pthread_mutex_unlock( &mutex );
125 				return true;
126 			}
127 
128 			//convert milliseconds to posix time
129 			struct timeval tv;
130 			gettimeofday( &tv, nullptr );
131 			struct timespec tm;
132 			tm.tv_sec = milliseconds / 1000 + tv.tv_sec;
133 			tm.tv_nsec = ( milliseconds % 1000 ) * 1000000 + tv.tv_usec * 1000;
134 
135 			int ret = 0;
136 			do
137 			{
138 				ret = pthread_cond_timedwait( &condition, &mutex, &tm );
139 			} while( ret == EINTR );
140 
141 			sched_yield();
142 
143 			pthread_mutex_unlock( &mutex );
144 
145 			AutoResetIfNeed();
146 			return ret == 0;
147 		}
148 
149 	};
150 
151 }
152 
153 
154