aboutsummaryrefslogtreecommitdiff
path: root/common/timer.cpp
blob: b6c1ce571048f1f8a7f2d1244da8428031184bb2 (plain)
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
/* ScummVM - Scumm Interpreter
 * Copyright (C) 2002-2003 The ScummVM project
 *
 * 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.
 *
 * $Header$
 */

#ifndef __MORPHOS__

#include "stdafx.h"
#include "common/scummsys.h"
#include "common/timer.h"
#include "common/util.h"

Timer *g_timer = NULL;

Timer::Timer(OSystem *system) :
	_system(system),
	_mutex(0),
	_timerHandler(0),
	_lastTime(0) {

	_mutex = _system->create_mutex();

	g_timer = this;
	
	for (int i = 0; i < MAX_TIMERS; i++) {
		_timerSlots[i].procedure = NULL;
		_timerSlots[i].interval = 0;
		_timerSlots[i].counter = 0;
	}

	_thisTime = _system->get_msecs();

	// Set the timer last, after everything has been initialised
	_system->set_timer(&timer_handler, 10);

}

Timer::~Timer() {
	_system->set_timer(0, 0);

	{
		Common::StackLock lock(_mutex);
		for (int i = 0; i < MAX_TIMERS; i++) {
			_timerSlots[i].procedure = NULL;
			_timerSlots[i].interval = 0;
			_timerSlots[i].counter = 0;
		}
	}


	// FIXME: There is still a potential race condition here, depending on how
	// the system backend implements set_timer: If timers are done using
	// threads, and if set_timer does *not* gurantee that after it terminates
	// that timer thread is not run anymore, we are fine. However, if the timer
	// is still running in parallel to this destructor, then it might be that
	// it is still waiting for the _mutex. So, again depending on the backend,
	// we might end up unlocking the mutex then immediately deleting it, while
	// the timer thread is about to lock it.
	_system->delete_mutex(_mutex);
}

int Timer::timer_handler(int t) {
	if (g_timer)
		return g_timer->handler(t);
	return 0;
}

int Timer::handler(int t) {
	Common::StackLock lock(_mutex);
	uint32 interval, l;

	_lastTime = _thisTime;
	_thisTime = _system->get_msecs();
	interval = 1000 * (_thisTime - _lastTime);

	for (l = 0; l < MAX_TIMERS; l++) {
		if (_timerSlots[l].procedure && _timerSlots[l].interval > 0) {
			_timerSlots[l].counter -= interval;
			while (_timerSlots[l].counter <= 0) {
				// A small paranoia check which catches the case where
				// a timer removes itself (which it never should do).
				assert(_timerSlots[l].procedure && _timerSlots[l].interval > 0);
				_timerSlots[l].counter += _timerSlots[l].interval;
				_timerSlots[l].procedure(_timerSlots[l].refCon);
			}
		}
	}

	return t;
}

bool Timer::installTimerProc(TimerProc procedure, int32 interval, void *refCon) {
	assert(interval > 0);
	Common::StackLock lock(_mutex);

	for (int l = 0; l < MAX_TIMERS; l++) {
		if (!_timerSlots[l].procedure) {
			_timerSlots[l].procedure = procedure;
			_timerSlots[l].interval = interval;
			_timerSlots[l].counter = interval;
			_timerSlots[l].refCon = refCon;
			return true;
		}
	}

	warning("Couldn't find free timer slot!");
	return false;
}

void Timer::removeTimerProc(TimerProc procedure) {
	Common::StackLock lock(_mutex);

	for (int l = 0; l < MAX_TIMERS; l++) {
		if (_timerSlots[l].procedure == procedure) {
			_timerSlots[l].procedure = 0;
			_timerSlots[l].interval = 0;
			_timerSlots[l].counter = 0;
			_timerSlots[l].refCon = 0;
		}
	}
}

#endif