Convert to streaming channel-based output interface

goborator.go

@@ -16,7 +16,7 @@ type Gaborator struct {
 	audioBlockSize            int
 	bandcenterCache           []float32
 	firstBandCache            int
-	fixedCoefficents          [][]float32
+	coefficientOutputChannel  chan []float32
 	frequencyBinTimeStepSize  int
 	bandsPerOctave            int
 	coefficients              [][]float32
@@ -32,7 +32,6 @@ func NewGaborator(blockSize int, sampleRate float64, bandsPerOctave int, minimum
 		frequencyBinTimeStepSize:  stepSize,
 		bandsPerOctave:            bandsPerOctave,
 		mostRecentCoefficentIndex: 0,
-		fixedCoefficents:          make([][]float32, 0, 16384), //preallocate
 	}
 
 	g.latency = int64(C.gaborator_get_anal_support(g.pointer))
@@ -118,7 +117,7 @@ func (g *Gaborator) gaborTransform(audioData []float32) {
 				g.mostRecentCoefficentIndex = coefficientIndex
 				// "copy" the oldest data to the history
 				// the slice can be reused thanks to the oldest being filled with zeros just after
-				g.fixedCoefficents = append(g.fixedCoefficents, g.coefficients[circularIndex])
+				g.coefficientOutputChannel <- g.coefficients[circularIndex]
 				// fill the oldest with zeros
 				g.coefficients[circularIndex] = make([]float32, len(g.coefficients[circularIndex]))
 			}
@@ -130,44 +129,58 @@ func (g *Gaborator) gaborTransform(audioData []float32) {
 	}
 }
 
-func (g *Gaborator) GaborBlockTransform(source chan []float32) [][]float32 {
+func (g *Gaborator) GetChannel() chan []float32 {
 
-	for {
-		block, more := <-source
-		if !more {
-			break
-		}
-		err := g.Process(block)
-		if err != nil {
-			log.Panic(err)
-		}
+	if g.coefficientOutputChannel == nil {
+		g.coefficientOutputChannel = make(chan []float32)
 	}
 
-	g.ProcessingFinished()
-
-	return g.coefficients
+	return g.coefficientOutputChannel
 }
 
-func (g *Gaborator) GaborTransform(source chan float32) [][]float32 {
+func (g *Gaborator) GaborBlockTransform(source chan []float32) (channel chan []float32) {
 
-	audioData := make([]float32, 0, g.audioBlockSize)
+	channel = g.GetChannel()
+	go func() {
+		defer g.ProcessingFinished()
 
-	for {
-		f, more := <-source
-		if !more {
-			break
+		for {
+			block, more := <-source
+			if !more {
+				break
+			}
+			err := g.Process(block)
+			if err != nil {
+				log.Panic(err)
+			}
 		}
-		audioData = append(audioData, f)
+	}()
 
-		for len(audioData) >= g.audioBlockSize {
-			g.gaborTransform(audioData[0:g.audioBlockSize])
-			audioData = audioData[:0]
+	return channel
+}
+
+func (g *Gaborator) GaborTransform(source chan float32) (channel chan []float32) {
+	channel = g.GetChannel()
+
+	go func() {
+		defer g.ProcessingFinished()
+		audioData := make([]float32, 0, g.audioBlockSize)
+
+		for {
+			f, more := <-source
+			if !more {
+				break
+			}
+			audioData = append(audioData, f)
+
+			for len(audioData) >= g.audioBlockSize {
+				g.gaborTransform(audioData[0:g.audioBlockSize])
+				audioData = audioData[:0]
+			}
 		}
-	}
+	}()
 
-	g.ProcessingFinished()
-
-	return g.coefficients
+	return channel
 }
 func (g *Gaborator) Process(block []float32) error {
 
@@ -182,6 +195,10 @@ func (g *Gaborator) ProcessingFinished() {
 		C.gaborator_release(g.pointer)
 		g.pointer = nil
 	}
+	if g.coefficientOutputChannel != nil {
+		close(g.coefficientOutputChannel)
+		g.coefficientOutputChannel = nil
+	}
 }
 
 func (g *Gaborator) GetStepSize() int {
@@ -196,10 +213,6 @@ func (g *Gaborator) GetSampleRate() float64 {
 	return g.sampleRate
 }
 
-func (g *Gaborator) GetCoefficients() [][]float32 {
-	return g.fixedCoefficents
-}
-
 func (g *Gaborator) GetBandwidth() float64 {
 	return 1200. / float64(g.bandsPerOctave)
 }

goborator_test.go

@@ -33,10 +33,10 @@ func TestGoborator(t *testing.T) {
 		}
 	}()
 
-	ob.GaborTransform(channel)
-
-	for i, c := range ob.GetCoefficients() {
+	var i = 0
+	for c := range ob.GaborTransform(channel) {
 		fmt.Printf("%d: %+F\n", i, c)
+		i++
 	}
 
 }