core/elapsedtimer: add ElapsedTimer

src/core/elapsedtimer.cpp

@@ -0,0 +1,22 @@
+#include "elapsedtimer.hpp"
+
+#include <qtypes.h>
+
+ElapsedTimer::ElapsedTimer() { this->timer.start(); }
+
+qreal ElapsedTimer::elapsed() { return static_cast<qreal>(this->elapsedNs()) / 1000000000.0; }
+
+qreal ElapsedTimer::restart() { return static_cast<qreal>(this->restartNs()) / 1000000000.0; }
+
+qint64 ElapsedTimer::elapsedMs() { return this->timer.elapsed(); }
+
+qint64 ElapsedTimer::restartMs() { return this->timer.restart(); }
+
+qint64 ElapsedTimer::elapsedNs() { return this->timer.nsecsElapsed(); }
+
+qint64 ElapsedTimer::restartNs() {
+	// see qelapsedtimer.cpp
+	auto old = this->timer;
+	this->timer.start();
+	return old.durationTo(this->timer).count();
+}

src/core/elapsedtimer.hpp

@@ -0,0 +1,45 @@
+#pragma once
+
+#include <qelapsedtimer.h>
+#include <qobject.h>
+#include <qqmlintegration.h>
+#include <qtmetamacros.h>
+#include <qtypes.h>
+
+///! Measures time between events
+/// The ElapsedTimer measures time since its last restart, and is useful
+/// for determining the time between events that don't supply it.
+class ElapsedTimer: public QObject {
+	Q_OBJECT;
+	QML_ELEMENT;
+
+public:
+	explicit ElapsedTimer();
+
+	/// Return the number of seconds since the timer was last
+	/// started or restarted, with nanosecond precision.
+	Q_INVOKABLE qreal elapsed();
+
+	/// Restart the timer, returning the number of seconds since
+	/// the timer was last started or restarted, with nanosecond precision.
+	Q_INVOKABLE qreal restart();
+
+	/// Return the number of milliseconds since the timer was last
+	/// started or restarted.
+	Q_INVOKABLE qint64 elapsedMs();
+
+	/// Restart the timer, returning the number of milliseconds since
+	/// the timer was last started or restarted.
+	Q_INVOKABLE qint64 restartMs();
+
+	/// Return the number of nanoseconds since the timer was last
+	/// started or restarted.
+	Q_INVOKABLE qint64 elapsedNs();
+
+	/// Restart the timer, returning the number of nanoseconds since
+	/// the timer was last started or restarted.
+	Q_INVOKABLE qint64 restartNs();
+
+private:
+	QElapsedTimer timer;
+};