aboutsummaryrefslogtreecommitdiff
path: root/backends/timer/default/default-timer.cpp
blob: 5b133660e0db4bfce98f9736b90c2b5419a8deb1 (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
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
/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include "common/scummsys.h"
#include "backends/timer/default/default-timer.h"
#include "common/util.h"
#include "common/system.h"

struct TimerSlot {
	Common::TimerManager::TimerProc callback;
	void *refCon;
	Common::String id;
	uint32 interval;	// in microseconds

	uint32 nextFireTime;	// in milliseconds
	uint32 nextFireTimeMicro;	// microseconds part of nextFire

	TimerSlot *next;
};

void insertPrioQueue(TimerSlot *head, TimerSlot *newSlot) {
	// The head points to a fake anchor TimerSlot; this common
	// trick allows us to get rid of many special cases.

	const uint32 nextFireTime = newSlot->nextFireTime;
	TimerSlot *slot = head;
	newSlot->next = 0;

	// Insert the new slot into the sorted list of already scheduled
	// timers in such a way that the list stays sorted...
	while (true) {
		assert(slot);
		if (slot->next == 0 || nextFireTime < slot->next->nextFireTime) {
			newSlot->next = slot->next;
			slot->next = newSlot;
			return;
		}
		slot = slot->next;
	}
}


DefaultTimerManager::DefaultTimerManager() :
	_timerHandler(0),
	_head(0) {

	_head = new TimerSlot();
	memset(_head, 0, sizeof(TimerSlot));
}

DefaultTimerManager::~DefaultTimerManager() {
	Common::StackLock lock(_mutex);

	TimerSlot *slot = _head;
	while (slot) {
		TimerSlot *next = slot->next;
		delete slot;
		slot = next;
	}
	_head = 0;
}

void DefaultTimerManager::handler() {
	Common::StackLock lock(_mutex);

	const uint32 curTime = g_system->getMillis();

	// Repeat as long as there is a TimerSlot that is scheduled to fire.
	TimerSlot *slot = _head->next;
	while (slot && slot->nextFireTime < curTime) {
		// Remove the slot from the priority queue
		_head->next = slot->next;

		// Update the fire time and reinsert the TimerSlot into the priority
		// queue.
		assert(slot->interval > 0);
		slot->nextFireTime += (slot->interval / 1000);
		slot->nextFireTimeMicro += (slot->interval % 1000);
		if (slot->nextFireTimeMicro > 1000) {
			slot->nextFireTime += slot->nextFireTimeMicro / 1000;
			slot->nextFireTimeMicro %= 1000;
		}
		insertPrioQueue(_head, slot);

		// Invoke the timer callback
		assert(slot->callback);
		slot->callback(slot->refCon);

		// Look at the next scheduled timer
		slot = _head->next;
	}
}

bool DefaultTimerManager::installTimerProc(TimerProc callback, int32 interval, void *refCon, const Common::String &id) {
	assert(interval > 0);
	Common::StackLock lock(_mutex);

	if (_callbacks.contains(id)) {
		if (_callbacks[id] != callback) {
			error("Different callbacks are referred by same name (%s)", id.c_str());
		}
	}
	TimerSlotMap::const_iterator i;

	for (i = _callbacks.begin(); i != _callbacks.end(); ++i) {
		if (i->_value == callback) {
			error("Same callback is referred by different names (%s vs %s)", i->_key.c_str(), id.c_str());
		}
	}
	_callbacks[id] = callback;

	TimerSlot *slot = new TimerSlot;
	slot->callback = callback;
	slot->refCon = refCon;
	slot->id = id;
	slot->interval = interval;
	slot->nextFireTime = g_system->getMillis() + interval / 1000;
	slot->nextFireTimeMicro = interval % 1000;
	slot->next = 0;

	// FIXME: It seems we do allow the client to add one callback multiple times over here,
	// but "removeTimerProc" will remove *all* added instances. We should either prevent
	// multiple additions of a timer proc OR we should change removeTimerProc to only remove
	// a specific timer proc entry.
	// Probably we can safely just allow a single addition of a specific function once
	// and just update our Timer documentation accordingly.
	insertPrioQueue(_head, slot);

	return true;
}

void DefaultTimerManager::removeTimerProc(TimerProc callback) {
	Common::StackLock lock(_mutex);

	TimerSlot *slot = _head;

	while (slot->next) {
		if (slot->next->callback == callback) {
			TimerSlot *next = slot->next->next;
			delete slot->next;
			slot->next = next;
		} else {
			slot = slot->next;
		}
	}

	for (TimerSlotMap::iterator i = _callbacks.begin(), end = _callbacks.end(); i != end; ++i) {
		if (i->_value == callback)
			_callbacks.erase(i);
	}
}