[AFV] Finalize blocking tone

Blocking tone is emitted if more than one station is received
in parallel.

src/blacksound/sampleprovider/sinusgenerator.cpp

@@ -0,0 +1,41 @@
+/* Copyright (C) 2019
+ * swift project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+#include "sinusgenerator.h"
+#include <cmath>
+
+namespace BlackSound
+{
+    namespace SampleProvider
+    {
+        CSinusGenerator::CSinusGenerator(double frequency, QObject *parent) :
+            ISampleProvider(parent),
+            m_frequency(frequency)
+        {}
+
+        int CSinusGenerator::readSamples(QVector<float> &samples, qint64 count)
+        {
+            samples.clear();
+            samples.fill(0, static_cast<int>(count));
+
+            for (int sampleCount = 0; sampleCount < count; sampleCount++)
+            {
+                double multiple = m_twoPi * m_frequency / m_sampleRate;
+                double sampleValue = m_gain * qSin(m_nSample * multiple);
+                samples[sampleCount] = static_cast<float>(sampleValue);
+                m_nSample++;
+            }
+            return static_cast<int>(count);
+        }
+
+        void CSinusGenerator::setFrequency(double frequency)
+        {
+            m_frequency = frequency;
+        }
+    } // ns
+} // ns