Added DJ audio track player

audioplayer.h

@@ -20,25 +20,36 @@ public:
     void writeSamples(frame_t *begin, frame_t *end);
 
     bool playing() const { return m_playing; }
-    void setPlaying(bool playing) { m_playing = playing; emit playingChanged(playing); }
+    void setPlaying(bool playing);
 
-    std::size_t position() const { return m_position; }
-    void setPosition(std::size_t position) { m_position = position; emit positionChanged(position); }
+    double position() const { return m_position; }
+    void setPosition(double position);
+
+    float speed() const { return m_speed; }
+    void setSpeed(float speed);
+
+    float volume() const { return m_volume; }
+    void setVolume(float volume);
 
     const QAudioBuffer &buffer() const { return m_buffer; }
-    void setBuffer(const QAudioBuffer &buffer) { emit bufferChanged(m_buffer = buffer); }
+    void setBuffer(const QAudioBuffer &buffer);
 
+    void togglePlaying();
     void restart();
     void stop();
 
 signals:
     void playingChanged(bool playing);
-    void positionChanged(std::size_t position);
+    void positionChanged(double position);
+    void speedChanged(float speed);
+    void volumeChanged(float volume);
     void bufferChanged(const QAudioBuffer &buffer);
 
 private:
     bool m_playing{false};
-    std::size_t m_position{};
+    double m_position{};
+    float m_speed{1.f};
+    float m_volume{1.f};
     QAudioBuffer m_buffer;
 
     QDateTime m_lastPositionUpdate;