Data copy/slice optimizations

goborator.go

@@ -16,7 +16,6 @@ type Gaborator struct {
 	audioBlockSize            int
 	bandcenterCache           []float32
 	firstBandCache            int
-	audioDataToTransform      []float32
 	fixedCoefficents          [][]float32
 	frequencyBinTimeStepSize  int
 	bandsPerOctave            int
@@ -30,10 +29,10 @@ func NewGaborator(blockSize int, sampleRate float64, bandsPerOctave int, minimum
 		pointer:                   unsafe.Pointer(C.gaborator_initialize(C.double(sampleRate), C.int(bandsPerOctave), C.double(minimumFrequency), C.double(referenceFrequency), C.double(maximumFrequency))),
 		sampleRate:                sampleRate,
 		audioBlockSize:            blockSize,
-		audioDataToTransform:      make([]float32, blockSize),
 		frequencyBinTimeStepSize:  stepSize,
 		bandsPerOctave:            bandsPerOctave,
 		mostRecentCoefficentIndex: 0,
+		fixedCoefficents:          make([][]float32, 0, 16384), //preallocate
 	}
 
 	g.latency = int64(C.gaborator_get_anal_support(g.pointer))
@@ -101,7 +100,7 @@ func (g *Gaborator) gaborTransform(audioData []float32) {
 	for i := 0; i < len(analysisResult); i += 3 {
 		band := int(analysisResult[i])
 		audioSample := int(analysisResult[i+1])
-		coefficient := analysisResult[i+2]
+		coefficient := float32(analysisResult[i+2])
 
 		coefficientIndex := audioSample/g.frequencyBinTimeStepSize - g.coefficientIndexOffset
 		bandIndex := band - g.firstBandCache
@@ -117,14 +116,11 @@ func (g *Gaborator) gaborTransform(audioData []float32) {
 			if coefficientIndex > g.mostRecentCoefficentIndex && coefficientIndex > len(g.coefficients) {
 				// keep the new maximum
 				g.mostRecentCoefficentIndex = coefficientIndex
-				// copy the oldest data to the history
-				g.fixedCoefficents = append(g.fixedCoefficents, make([]float32, len(g.coefficients[circularIndex])))
-				copy(g.fixedCoefficents[len(g.fixedCoefficents)-1], g.coefficients[circularIndex])
-
+				// "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])
 				// fill the oldest with zeros
-				for j := range g.coefficients[circularIndex] {
-					g.coefficients[circularIndex][j] = 0.
-				}
+				g.coefficients[circularIndex] = make([]float32, len(g.coefficients[circularIndex]))
 			}
 			// due to reduction in precision (from audio sample accuracy to steps) multiple
 			// magnitudes could be placed in the same stepIndex, bandIndex pair.
@@ -212,18 +208,12 @@ func (g *Gaborator) GetLatency() int64 {
 	return g.latency
 }
 
-func (g *Gaborator) analyze(block []float32) []float32 {
+func (g *Gaborator) analyze(block []float32) []C.float {
 	//log.Printf("analyze block len %d", len(block))
 	C.gaborator_analyze(g.pointer, (*C.float)(&block[0]), C.int(len(block)))
 	cSize := uintptr(C.gaborator_get_array_length(g.pointer))
 
 	//log.Print(cSize)
 	ptr := (*C.float)(C.gaborator_get_array(g.pointer))
-
-	result := make([]float32, cSize)
-	for i, v := range unsafe.Slice(ptr, cSize) {
-		result[i] = float32(v)
-	}
-
-	return result
+	return unsafe.Slice(ptr, cSize)
 }

goborator_test.go

@@ -1,6 +1,7 @@
 package goborator
 
 import (
+	"encoding/binary"
 	"fmt"
 	"os"
 	"testing"
@@ -15,8 +16,27 @@ func TestGoborator(t *testing.T) {
 		t.Error(err)
 		return
 	}
-	ob.GaborTransform(file)
+
+	channel := make(chan float32)
+
+	go func() {
+		defer close(channel)
+		defer file.Close()
+
+		var f float32
+		for {
+			err = binary.Read(file, binary.LittleEndian, &f)
+			if err != nil {
+				return
+			}
+			channel <- f
+		}
+	}()
+
+	ob.GaborTransform(channel)
+
 	for i, c := range ob.GetCoefficients() {
 		fmt.Printf("%d: %+F\n", i, c)
 	}
+
 }