Added 'timer' backend module, based on the existing TimerManager code (work in progress)

svn-id: r23279

2 files changed, 189 insertions, 0 deletions

diff --git a/backends/timer/default/default-timer.cpp b/backends/timer/default/default-timer.cpp
new file mode 100644
index 0000000000..907c715a07
--- /dev/null
+++ b/backends/timer/default/default-timer.cpp
@@ -0,0 +1,130 @@
+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2002-2006 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ */
+
+#include "common/stdafx.h"
+#include "common/scummsys.h"
+#include "backends/timer/default/default-timer.h"
+#include "common/util.h"
+#include "common/system.h"
+
+namespace Common {
+// FIXME: Hack: This global variable shouldn't be declared here; in fact it 
+// probably shouldn't be declared at all but rather a different method to
+// query the TimerManager object should be invented.
+TimerManager *g_timer = NULL;
+}
+
+DefaultTimerManager::DefaultTimerManager(OSystem *system) :
+	_system(system),
+	_timerHandler(0),
+	_lastTime(0) {
+
+	Common::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->getMillis();
+
+	// Set the timer last, after everything has been initialised
+	_system->setTimerCallback(&timer_handler, 10);
+
+}
+
+DefaultTimerManager::~DefaultTimerManager() {
+	// Remove the timer callback.
+	// Note: backends *must* gurantee that after this method call returns,
+	// the handler is not in use anymore; else race condtions could occur.
+	_system->setTimerCallback(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;
+		}
+	}
+}
+
+int DefaultTimerManager::timer_handler(int t) {
+	if (Common::g_timer)
+		return ((DefaultTimerManager *)Common::g_timer)->handler(t);
+	return 0;
+}
+
+int DefaultTimerManager::handler(int t) {
+	Common::StackLock lock(_mutex);
+	uint32 interval, l;
+
+	_lastTime = _thisTime;
+	_thisTime = _system->getMillis();
+	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 DefaultTimerManager::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 DefaultTimerManager::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 = 1;	// Work around a problem when a timer proc removes itself
+			_timerSlots[l].refCon = 0;
+		}
+	}
+}
diff --git a/backends/timer/default/default-timer.h b/backends/timer/default/default-timer.h
new file mode 100644
index 0000000000..12779cc59c
--- /dev/null
+++ b/backends/timer/default/default-timer.h
@@ -0,0 +1,59 @@
+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2002-2006 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ */
+
+#ifndef BACKENDS_TIMER_DEFAULT_H
+#define BACKENDS_TIMER_DEFAULT_H
+
+#include "common/timer.h"
+#include "common/mutex.h"
+
+class OSystem;
+
+class DefaultTimerManager : public Common::TimerManager {
+private:
+	enum {
+		MAX_TIMERS = 8
+	};
+	OSystem *_system;
+	Common::Mutex _mutex;
+	void *_timerHandler;
+	int32 _thisTime;
+	int32 _lastTime;
+
+	struct TimerSlots {
+		TimerProc procedure;
+		int32 interval;
+		int32 counter;
+		void *refCon;
+	} _timerSlots[MAX_TIMERS];
+
+public:
+	DefaultTimerManager(OSystem *system);
+	~DefaultTimerManager();
+	bool installTimerProc(TimerProc proc, int32 interval, void *refCon);
+	void removeTimerProc(TimerProc proc);
+
+protected:
+	static int timer_handler(int t);
+	int handler(int t);
+};
+
+#endif