Minor code cleanups (#3)

* sound: move Pipe function to top of pipe.go

This is to make the more important code (e.g. exported
identifiers) be higher up, similar to how Discard is above
discard in sink.go

* sound: add trailing period after Source doc comment

* sound: remove receiver name from discard as its not used

* sound: add .gitignore to ignore generated WAV files

* sound: clarify some comments

* sound: consistent use of channel form comments

Single channel and 2-channel vs. mono-channel and stero.

Now MonoCd and MonoDvd have the same usage, as do
StereoCd and StereoDvd

* sound/freq: use switch to increase readability of freq.T.String

Also, remove unnecessary else blocks; i.e. change:

	if foo {
		return bar
	} else {
		return baz
	}

To:

	if foo {
		return bar
	}
	return baz

* sound/freq: fix typo in RadsPerAt comment and update T comment

* sound/gen: add trailing dot in package doc comment

* sound/sample: fix minor typo

.gitignore

@@ -0,0 +1 @@
+gen/*.wav

form.go

@@ -32,7 +32,7 @@ func NewForm(f freq.T, c int) Form {
 	return &_form{c: c, f: f}
 }
 
-// Interface Form specifies the logical content of pcm audio data.  data,
+// Interface Form specifies the logical content of pcm audio data,
 // namely the number of channels and the sample rate.  Form does not specify
 // the in-memory layout of pcm audio data such as sample codec or whether or
 // not the data is channel-interleaved.
@@ -49,17 +49,17 @@ func MonoCd() Form {
 	return &_form{c: 1, f: 44100 * freq.Hertz}
 }
 
-// MonoDvd gives a mono-channel Form at Dvd sample rate (48kHz).
+// MonoDvd gives a single channel form at Dvd sample rate (48kHz).
 func MonoDvd() Form {
 	return &_form{c: 1, f: 48000 * freq.Hertz}
 }
 
-// StereoCd returns a stereo form at CD sampling rate.
+// StereoCd returns a 2-channel form at CD sampling rate.
 func StereoCd() Form {
 	return &_form{c: 2, f: 44100 * freq.Hertz}
 }
 
-// StereoDvd gives a 2-channel Form at Dvd sample rate (48kHz).
+// StereoDvd gives a 2-channel form at Dvd sample rate (48kHz).
 func StereoDvd() Form {
 	return &_form{c: 2, f: 48000 * freq.Hertz}
 }

freq/t.go

@@ -10,7 +10,7 @@ import (
 	"time"
 )
 
-// Type Frequency represents a frequency.
+// T represents a frequency.
 type T int64
 
 // Different levels of "ouch".
@@ -26,43 +26,36 @@ const (
 
 // String implements Stringer.
 func (f T) String() string {
-	if f < 0 {
+	switch {
+	case f < 0:
 		if -f >= 0 {
 			return fmt.Sprintf("-%s", -f)
 		}
 		return "-Inf Hz"
-	}
-	if f < MicroHertz {
+	case f < MicroHertz:
 		return fmt.Sprintf("%dnHz", f)
-	}
-	if f < MilliHertz {
+	case f < MilliHertz:
 		if f%MicroHertz == 0 {
 			return fmt.Sprintf("%.3f\u00B5Hz", float64(f)/float64(MicroHertz))
-		} else {
-			return fmt.Sprintf("%.6f\u00B5Hz", float64(f)/float64(MicroHertz))
 		}
-	}
-	if f < Hertz {
+		return fmt.Sprintf("%.6f\u00B5Hz", float64(f)/float64(MicroHertz))
+	case f < Hertz:
 		if f%MilliHertz == 0 {
 			return fmt.Sprintf("%.3fmiHz", float64(f)/float64(MilliHertz))
 		} else if f%MicroHertz == 0 {
 			return fmt.Sprintf("%.6fmiHz", float64(f)/float64(MilliHertz))
-		} else {
-			return fmt.Sprintf("%.9fmiHz", float64(f)/float64(MilliHertz))
 		}
-	}
-	if f < KiloHertz {
+		return fmt.Sprintf("%.9fmiHz", float64(f)/float64(MilliHertz))
+	case f < KiloHertz:
 		if f%Hertz == 0 {
 			return fmt.Sprintf("%.0fHz", float64(f)/float64(Hertz))
 		} else if f%MilliHertz == 0 {
 			return fmt.Sprintf("%.3fHz", float64(f)/float64(Hertz))
 		} else if f%MicroHertz == 0 {
 			return fmt.Sprintf("%.6fHz", float64(f)/float64(Hertz))
-		} else {
-			return fmt.Sprintf("%.9fHz", float64(f)/float64(Hertz))
 		}
-	}
-	if f < MegaHertz {
+		return fmt.Sprintf("%.9fHz", float64(f)/float64(Hertz))
+	case f < MegaHertz:
 		if f%KiloHertz == 0 {
 			return fmt.Sprintf("%.0fkHz", float64(f)/float64(KiloHertz))
 		} else if f%Hertz == 0 {
@@ -71,11 +64,9 @@ func (f T) String() string {
 			return fmt.Sprintf("%.6fkHz", float64(f)/float64(KiloHertz))
 		} else if f%MicroHertz == 0 {
 			return fmt.Sprintf("%.9fkHz", float64(f)/float64(KiloHertz))
-		} else {
-			return fmt.Sprintf("%.12fkHz", float64(f)/float64(KiloHertz))
 		}
-	}
-	if f < GigaHertz {
+		return fmt.Sprintf("%.12fkHz", float64(f)/float64(KiloHertz))
+	case f < GigaHertz:
 		return fmt.Sprintf("%.3fmgHz", float64(f)/float64(MegaHertz))
 	}
 	return fmt.Sprintf("%.3fgHz", float64(f)/float64(GigaHertz))
@@ -114,7 +105,7 @@ func (f T) Phase(d time.Duration) float64 {
 	return 2.0 * math.Pi * (math.Mod(df, p) / p)
 }
 
-// RadPerAt gives the radians per sample of a signal at frequency f sampled at
+// RadsPerAt gives the radians per sample of a signal at frequency f sampled at
 // frequency r.
 func (f T) RadsPerAt(s T) float64 {
 	d := float64(f) / float64(s)

gen/doc.go

@@ -1,5 +1,5 @@
 // Copyright 2018 The ZikiChomgo Authors. All rights reserved.  Use of this source
 // code is governed by a license that can be found in the License file.
 
-// Package gen provides audio generators
+// Package gen provides audio generators.
 package gen /* import "zikichombo.org/sound/gen" */

pipe.go

@@ -8,6 +8,18 @@ import (
 	"sync"
 )
 
+// Pipe creates a pair of Source and Sink such that writes to the sink
+// are passed through to reads from the Source.
+//
+// The returned source, sink are safe for use in multiple goroutines.
+func Pipe(v Form) (Source, Sink) {
+	pC := make(chan *packet)
+	doneC := make(chan struct{})
+	nC := make(chan int)
+	p := &pipe{Form: v, pC: pC, doneC: doneC, nC: nC}
+	return p, p
+}
+
 type pipe struct {
 	Form
 	wMu   sync.Mutex
@@ -120,15 +132,3 @@ func copyFrames(dst *packet, src *packet, nc int) int {
 	}
 	return t
 }
-
-// Pipe creates a pair of Source and Sink such that writes to the sink
-// are passed through to reads from the Source.
-//
-// The returned source, sink are safe for use in multiple goroutines.
-func Pipe(v Form) (Source, Sink) {
-	pC := make(chan *packet)
-	doneC := make(chan struct{})
-	nC := make(chan int)
-	p := &pipe{Form: v, pC: pC, doneC: doneC, nC: nC}
-	return p, p
-}

sample/codec.go

@@ -129,7 +129,7 @@ func (s Codec) FromFloat64(v float64) uint64 {
 	return bo.Uint64(dst[:])
 }
 
-// Decode decodes source samples encoded ito src using codec
+// Decode decodes source samples encoded into src using codec
 // s into a slice of float64s.
 //
 // If len(dst)*s.Bytes() > len(src) then Decode panics.

seek.go

@@ -34,9 +34,9 @@ type SinkSeeker interface {
 // support.
 type RandomAccess interface {
 	Seeker
-	// Receive is specified as in Source.
+	// Receive is as specified in Source.Receive.
 	Receive(dst []float64) (int, error)
-	// Send is specified as in Sink.
+	// Send is as specified as in Sink.Send.
 	Send(src []float64) error
 }
 
@@ -53,7 +53,7 @@ func When(s Seeker) time.Duration {
 	return s2d(s, s.Pos())
 }
 
-// Durations takes a Seeker and returns its total duration in
+// Duration takes a Seeker and returns its total duration in
 // time.
 func Duration(s Seeker) time.Duration {
 	return s2d(s, s.Len())

sink.go

@@ -26,18 +26,18 @@ var Discard Sink = &discard{}
 
 type discard struct{}
 
-func (d *discard) Send(v []float64) error {
+func (*discard) Send(d []float64) error {
 	return nil
 }
 
-func (d *discard) Close() error {
+func (*discard) Close() error {
 	return nil
 }
 
-func (d *discard) SampleRate() freq.T {
+func (*discard) SampleRate() freq.T {
 	return 0
 }
 
-func (d *discard) Channels() int {
+func (*discard) Channels() int {
 	return 1
 }

source.go

@@ -3,7 +3,7 @@
 
 package sound
 
-// Source is an interface for a source of samples
+// Source is an interface for a source of samples.
 type Source interface {
 	Form
 	Closer