Audio refactor

inc/streams/DataStream.h

@@ -47,6 +47,11 @@ DEALINGS IN THE SOFTWARE.
 
 #define DATASTREAM_SAMPLE_RATE_UNKNOWN      0.0f
 
+#define DATASTREAM_DONT_CARE                0
+#define DATASTREAM_NOT_WANTED               1
+#define DATASTREAM_WANTED                   2
+
+
 namespace codal
 {
     /**
@@ -55,7 +60,6 @@ namespace codal
     class DataSink
     {
     	public:
-
             virtual int pullRequest();
     };
 
@@ -64,6 +68,8 @@ namespace codal
     */
     class DataSource
     {
+        int    dataIsWanted;
+
     	public:
             virtual ManagedBuffer pull();
             virtual void connect(DataSink &sink);
@@ -72,27 +78,54 @@ namespace codal
             virtual int getFormat();
             virtual int setFormat(int format);
             virtual float getSampleRate();
-            virtual float requestSampleRate(float sampleRate);
+            virtual void dataWanted(int wanted);
+            virtual int isWanted();
+    };
+
+    /**
+     * This class acts as a base class for objects that serve both the DataSource and DataSink interfaces.
+     * Classes anre not required to use this, but are strongly encouraged to use this as a base class, in order
+     * to reduce complexity, ensure consistent behaviour, and reduce duplicated code.
+     */
+    class DataSourceSink : public DataSource, public DataSink
+    {
+
+        public:
+            DataSink *downStream;
+            DataSource &upStream;
+
+             /**
+             * Constructor.
+             * Creates an empty DataSourceSink.
+             *
+             * @param upstream the component that will normally feed this datastream with data.
+             */
+            DataSourceSink(DataSource &upstream);
+            virtual ~DataSourceSink();
+
+            virtual void connect(DataSink &sink);
+            virtual bool isConnected();
+            virtual void disconnect();
+            virtual int getFormat();
+            virtual int setFormat(int format);
+            virtual float getSampleRate();
+            virtual void dataWanted(int wanted);
+            virtual int pullRequest();
     };
 
     /**
       * Class definition for DataStream.
       * A Datastream holds a number of ManagedBuffer references, provides basic flow control through a push/pull mechanism
       * and byte level access to the datastream, even if it spans different buffers.
       */
-    class DataStream : public DataSource, public DataSink
+    class DataStream : public DataSourceSink
     {
         uint16_t pullRequestEventCode;
-        uint16_t flowEventCode;
         ManagedBuffer nextBuffer;
         bool hasPending;
         bool isBlocking;
-        unsigned int missedBuffers;
         int downstreamReturn;
 
-        DataSink *downStream;
-        DataSource *upStream;
-
         public:
 
             /**
@@ -109,58 +142,12 @@ namespace codal
              */
             ~DataStream();
 
-            /**
-             * Controls if this component should emit flow state events.
-             * 
-             * @warning Should not be called mutliple times with `id == 0`, as it will spuriously reallocate event IDs
-             * 
-             * @param id If zero, this will auto-allocate a new event ID
-             * @return uint16_t The new event ID for this DataStream
-             */
-            uint16_t emitFlowEvents( uint16_t id = 0 );
-
             /**
              * Determines if any of the data currently flowing through this stream is held in non-volatile (FLASH) memory.
              * @return true if one or more of the ManagedBuffers in this stream reside in FLASH memory, false otherwise.
              */
             bool isReadOnly();
 
-            /**
-             * Attempts to determine if another component downstream of this one is _actually_ pulling data, and thus, data
-             * is flowing.
-             * 
-             * @return true If there is a count-match between `pullRequest` and `pull` calls.
-             * @return false If `pullRequest` calls are not currently being matched by `pull` calls.
-             */
-            bool isFlowing();
-
-            /**
-             * Define a downstream component for data stream.
-             *
-             * @sink The component that data will be delivered to, when it is available
-             */
-            virtual void connect(DataSink &sink) override;
-
-            /**
-             * Determines if this source is connected to a downstream component
-             * 
-             * @return true If a downstream is connected
-             * @return false If a downstream is not connected
-             */
-            virtual bool isConnected();
-
-            /**
-             * Define a downstream component for data stream.
-             *
-             * @sink The component that data will be delivered to, when it is available
-             */
-            virtual void disconnect() override;
-
-            /**
-             *  Determine the data format of the buffers streamed out of this component.
-             */
-            virtual int getFormat() override;
-
             /**
              * Determines if this stream acts in a synchronous, blocking mode or asynchronous mode. In blocking mode, writes to a full buffer
              * will result int he calling fiber being blocked until space is available. Downstream DataSinks will also attempt to process data
@@ -187,29 +174,7 @@ namespace codal
              */
             virtual int pullRequest();
 
-            /**
-             * Query the stream for its current sample rate.
-             * 
-             * If the current object is unable to determine this itself, it will pass the call upstream until it reaches a component can respond.
-             * 
-             * @warning The sample rate for a stream may change during its lifetime. If a component is sensitive to this, it should periodically check.
-             * 
-             * @return float The current sample rate for this stream, or `DATASTREAM_SAMPLE_RATE_UNKNOWN` if none is found.
-             */
-            virtual float getSampleRate() override;
-
-            /**
-             * Request a new sample rate on this stream.
-             * 
-             * Most components will simply forward this call upstream, and upon reaching a data source, if possible the source should change
-             * the sample rate to accomodate the request.
-             * 
-             * @warning Not all sample rates will be possible for all devices, so if the caller needs to know the _actual_ rate, they should check the returned value here
-             * 
-             * @param sampleRate The requested sample rate, to be handled by the nearest component capable of doing so.
-             * @return float The actual sample rate this stream will now run at, may differ from the requested sample rate.
-             */
-            virtual float requestSampleRate(float sampleRate) override;
+            virtual void connect(DataSink &sink);
 
         private:
             /**

inc/streams/EffectFilter.h

@@ -7,12 +7,8 @@
 
 namespace codal
 {
-    class EffectFilter : public DataSource, public DataSink
+    class EffectFilter : public DataSourceSink
     {
-        protected:
-
-        DataSink *downStream;
-        DataSource &upStream;
         bool deepCopy;
 
         public:
@@ -21,15 +17,6 @@ namespace codal
         ~EffectFilter();
 
         virtual ManagedBuffer pull();
-        virtual int pullRequest();
-    	virtual void connect( DataSink &sink );
-        bool isConnected();
-        virtual void disconnect();
-        virtual int getFormat();
-        virtual int setFormat( int format );
-
-        virtual float getSampleRate();
-        virtual float requestSampleRate(float sampleRate);
 
         /**
         * Defines if this filter should perform a deep copy of incoming data, or update data in place.

inc/streams/FIFOStream.h

@@ -9,7 +9,7 @@
 
 namespace codal {
 
-    class FIFOStream : public DataSource, public DataSink
+    class FIFOStream : public DataSourceSink
     {
         private:
 
@@ -20,21 +20,13 @@ namespace codal {
         bool allowInput;
         bool allowOutput;
 
-        DataSink *downStream;
-        DataSource &upStream;
-
         public:
 
         FIFOStream( DataSource &source );
         ~FIFOStream();
 
         virtual ManagedBuffer pull();
         virtual int pullRequest();
-    	virtual void connect( DataSink &sink );
-        bool isConnected();
-        virtual void disconnect();
-        virtual int getFormat();
-        virtual int setFormat( int format );
         int length();
         void dumpState();
 

inc/streams/LevelDetectorSPL.h

@@ -36,6 +36,7 @@ DEALINGS IN THE SOFTWARE.
 #define LEVEL_DETECTOR_SPL_HIGH_THRESHOLD_PASSED             0x02
 #define LEVEL_DETECTOR_SPL_LOW_THRESHOLD_PASSED              0x04
 #define LEVEL_DETECTOR_SPL_CLAP                              0x08
+#define LEVEL_DETECTOR_SPL_DATA_REQUESTED                    0x10
 
 
 /**
@@ -82,6 +83,7 @@ DEALINGS IN THE SOFTWARE.
 #define LEVEL_DETECTOR_SPL_CLAP_MIN_LOUD_BLOCKS             2        // ensure noise not too short to be a clap
 #define LEVEL_DETECTOR_SPL_CLAP_MIN_QUIET_BLOCKS            20       // prevent very fast taps being registered as clap
 
+#define LEVEL_DETECTOR_SPL_TIMEOUT                          50      // Time in ms at which we request no further data.
 
 namespace codal{
     class LevelDetectorSPL : public CodalComponent, public DataSink
@@ -97,18 +99,18 @@ namespace codal{
         int             sigma;              // Running total of the samples in the current window.
         float           gain;
         float           minValue;
-        bool            activated;          // Has this component been connected yet
-        bool            enabled;            // Is the component currently running
-        int             unit;               // The units to be returned from this level detector (e.g. dB or linear 8bit)
-        int             quietBlockCount;    // number of quiet blocks consecutively - used for clap detection
-        int             noisyBlockCount;    // number of noisy blocks consecutively - used for clap detection
-        bool            inNoisyBlock;       // if had noisy and waiting to lower beyond lower threshold
-        float           maxRms;             // maximum rms within a noisy block
+        bool            enabled;            // Is the component currently running.
+        int             unit;               // The units to be returned from this level detector (e.g. dB or linear 8bit).
+        int             quietBlockCount;    // number of quiet blocks consecutively - used for clap detection.
+        int             noisyBlockCount;    // number of noisy blocks consecutively - used for clap detection.
+        bool            inNoisyBlock;       // if had noisy and waiting to lower beyond lower threshold.
+        float           maxRms;             // maximum rms within a noisy block.
 
         private:
-        uint64_t        timeout;            // The timestamp at which this component will cease actively sampling the data stream
-        uint8_t         bufferCount;        // Used to track that enough buffers have been seen since activation to output a valid value/event
-        FiberLock       resourceLock;
+        uint8_t         bufferCount;        // Used to track that enough buffers have been seen since activation to output a valid value/event.
+        uint8_t         listenerCount;      // The total number of active listeners to this component.
+        FiberLock       resourceLock;       // Fiberlock - used purely hold fibers requesting data before it is available.
+        uint64_t        timestamp;          // Timestamp of the last time someone requesed data from this component.
         public:
 
         /**
@@ -122,9 +124,13 @@ namespace codal{
           */
         LevelDetectorSPL(DataSource &source, float highThreshold, float lowThreshold, float gain,
             float minValue = 52,
-            uint16_t id = DEVICE_ID_SYSTEM_LEVEL_DETECTOR_SPL,
-            bool activateImmediately  = true);
+            uint16_t id = DEVICE_ID_SYSTEM_LEVEL_DETECTOR_SPL);
 
+        /**
+         * Periodic callback, every 6ms or so.
+         */
+        void periodicCallback();
+
         /**
          * Callback provided when data is ready.
          */
@@ -139,11 +145,10 @@ namespace codal{
         float getValue( int scale = -1 );
 
         /**
-         * Keep this component active and processing buffers so that events can be produced
-         * 
-         * @param state If set to true, this component will connect (if required) and start consuming buffers
+         * Callback when a listener to this component is added.
+         * n.b. we currently don't support removing listners (future work if necessary)
          */
-        void activateForEvents( bool state );
+        void listenerAdded();
 
         /**
          * Disable component