From d6408797755878783623690eeed2a6c1da909d73 Mon Sep 17 00:00:00 2001
From: faiface <faiface@ksp.sk>
Date: Wed, 5 Jul 2017 18:14:18 +0200
Subject: [PATCH] add Take decorator function
---
audio/compositors.go | 23 +++++++++++++++++++++++
audio/compositors_test.go | 16 ++++++++++++++++
2 files changed, 39 insertions(+)
diff --git a/audio/compositors.go b/audio/compositors.go
index bb4740f..ceed138 100644
--- a/audio/compositors.go
+++ b/audio/compositors.go
@@ -1,5 +1,28 @@
package audio
+import (
+ "math"
+ "time"
+)
+
+// Take returns a Streamer which streams s for at most d duration.
+func Take(d time.Duration, s Streamer) Streamer {
+ currSample := 0
+ numSamples := int(math.Ceil(d.Seconds() * SampleRate))
+ return StreamerFunc(func(samples [][2]float64) (n int, ok bool) {
+ if currSample >= numSamples {
+ return 0, false
+ }
+ toStream := numSamples - currSample
+ if len(samples) < toStream {
+ toStream = len(samples)
+ }
+ sn, sok := s.Stream(samples[:toStream])
+ currSample += sn
+ return sn, sok
+ })
+}
+
// 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
diff --git a/audio/compositors_test.go b/audio/compositors_test.go
index 4114b92..450430b 100644
--- a/audio/compositors_test.go
+++ b/audio/compositors_test.go
@@ -44,6 +44,22 @@ func collect(s audio.Streamer) [][2]float64 {
}
}
+func TestTake(t *testing.T) {
+ for i := 0; i < 7; i++ {
+ total := time.Nanosecond * time.Duration(1e8+rand.Intn(1e9))
+ s, data := randomDataStreamer(total)
+ d := time.Nanosecond * time.Duration(rand.Int63n(total.Nanoseconds()))
+ numSamples := int(math.Ceil(d.Seconds() * audio.SampleRate))
+
+ want := data[:numSamples]
+ got := collect(audio.Take(d, s))
+
+ if !reflect.DeepEqual(want, got) {
+ t.Error("Take not working correctly")
+ }
+ }
+}
+
func TestSeq(t *testing.T) {
var (
s = make([]audio.Streamer, 7)
--
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