Implement VolumeSampleProvider to gain in and output

fixup! Implement VolumeSampleProvider to gain in and output

src/blacksound/sampleprovider/volumesampleprovider.cpp

@@ -0,0 +1,40 @@
+/* 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.
+ */
+
+//! \file
+
+#include "volumesampleprovider.h"
+
+VolumeSampleProvider::VolumeSampleProvider(ISampleProvider *sourceProvider, QObject *parent) :
+    ISampleProvider(parent),
+    m_sourceProvider(sourceProvider)
+{ }
+
+int VolumeSampleProvider::readSamples(QVector<qint16> &samples, qint64 count)
+{
+    int samplesRead = m_sourceProvider->readSamples(samples, count);
+
+    if (! qFuzzyCompare(m_volume, 1.0))
+    {
+        for (int n = 0; n < samplesRead; n++)
+        {
+            samples[n] *= m_volume;
+        }
+    }
+    return samplesRead;
+}
+
+double VolumeSampleProvider::volume() const
+{
+    return m_volume;
+}
+
+void VolumeSampleProvider::setVolume(double volume)
+{
+    m_volume = volume;
+}

src/blacksound/sampleprovider/volumesampleprovider.h

@@ -0,0 +1,36 @@
+/* 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.
+ */
+
+//! \file
+
+#ifndef VOLUMESAMPLEPROVIDER_H
+#define VOLUMESAMPLEPROVIDER_H
+
+#include "blacksound/blacksoundexport.h"
+#include "blacksound/sampleprovider/sampleprovider.h"
+
+//! Pink noise generator
+class BLACKSOUND_EXPORT VolumeSampleProvider : public ISampleProvider
+{
+    Q_OBJECT
+
+public:
+    //! Noise generator
+    VolumeSampleProvider(ISampleProvider *sourceProvider, QObject *parent = nullptr);
+
+    virtual int readSamples(QVector<qint16> &samples, qint64 count) override;
+
+    double volume() const;
+    void setVolume(double volume);
+
+private:
+    ISampleProvider *m_sourceProvider;
+    double m_volume = 1.0;
+};
+
+#endif // guard