From c86834b8f67650edd7be90be9d2e04b4a6698278 Mon Sep 17 00:00:00 2001
From: faiface <faiface@ksp.sk>
Date: Wed, 5 Jul 2017 17:59:43 +0200
Subject: [PATCH] add Seq compositor
---
audio/compositors.go | 17 +++++++++++
audio/compositors_test.go | 63 +++++++++++++++++++++++++++++++++++++++
2 files changed, 80 insertions(+)
create mode 100644 audio/compositors.go
create mode 100644 audio/compositors_test.go
diff --git a/audio/compositors.go b/audio/compositors.go
new file mode 100644
index 0000000..bb4740f
--- /dev/null
+++ b/audio/compositors.go
@@ -0,0 +1,17 @@
+package audio
+
+// Seq takes zero or more Streamers and returns a Streamer which streams them one by one without pauses.
+func Seq(s ...Streamer) Streamer {
+ i := 0
+ return StreamerFunc(func(samples [][2]float64) (n int, ok bool) {
+ for i < len(s) && len(samples) > 0 {
+ sn, sok := s[i].Stream(samples)
+ samples = samples[sn:]
+ n, ok = n+sn, ok || sok
+ if !sok {
+ i++
+ }
+ }
+ return n, ok
+ })
+}
diff --git a/audio/compositors_test.go b/audio/compositors_test.go
new file mode 100644
index 0000000..4114b92
--- /dev/null
+++ b/audio/compositors_test.go
@@ -0,0 +1,63 @@
+package audio_test
+
+import (
+ "math"
+ "math/rand"
+ "reflect"
+ "testing"
+ "time"
+
+ "github.com/faiface/pixel/audio"
+)
+
+// randomDataStreamer generates random samples of duration d and returns a Streamer which streams
+// them and the data itself.
+func randomDataStreamer(d time.Duration) (s audio.Streamer, data [][2]float64) {
+ numSamples := int(math.Ceil(d.Seconds() * audio.SampleRate))
+ data = make([][2]float64, numSamples)
+ for i := range data {
+ data[i][0] = rand.Float64()*2 - 1
+ data[i][1] = rand.Float64()*2 - 1
+ }
+ return audio.StreamerFunc(func(samples [][2]float64) (n int, ok bool) {
+ if len(data) == 0 {
+ return 0, false
+ }
+ n = copy(samples, data)
+ data = data[n:]
+ return n, true
+ }), data
+}
+
+// collect drains Streamer s and returns all of the samples it streamed.
+func collect(s audio.Streamer) [][2]float64 {
+ var (
+ result [][2]float64
+ buf [512][2]float64
+ )
+ for {
+ n, ok := s.Stream(buf[:])
+ if !ok {
+ return result
+ }
+ result = append(result, buf[:n]...)
+ }
+}
+
+func TestSeq(t *testing.T) {
+ var (
+ s = make([]audio.Streamer, 7)
+ want [][2]float64
+ )
+ for i := range s {
+ var data [][2]float64
+ s[i], data = randomDataStreamer(time.Nanosecond * time.Duration(1e8+rand.Intn(1e9)))
+ want = append(want, data...)
+ }
+
+ got := collect(audio.Seq(s...))
+
+ if !reflect.DeepEqual(want, got) {
+ t.Error("Seq not working correctly")
+ }
+}
--
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