Use io.ReadSeeker instead of io.ReadCloser (#31)

bench_test.go

@@ -26,7 +26,7 @@ func BenchmarkDecode(b *testing.B) {
 	if err != nil {
 		b.Fatal(err)
 	}
-	src := &bytesReadCloser{bytes.NewReader(buf)}
+	src := bytes.NewReader(buf)
 	for i := 0; i < b.N; i++ {
 		if _, err := src.Seek(0, io.SeekStart); err != nil {
 			b.Fatal(err)

decode.go

@@ -111,9 +111,9 @@ func (d *Decoder) Seek(offset int64, whence int) (int64, error) {
 	return npos, nil
 }
 
-// Close is io.Closer's Close.
+// Close is io.Closer's Close. Close does nothing and always returns nil.
 func (d *Decoder) Close() error {
-	return d.source.Close()
+	return nil
 }
 
 // SampleRate returns the sample rate like 44100.
@@ -186,12 +186,12 @@ func (d *Decoder) Length() int64 {
 	return d.length
 }
 
-// NewDecoder decodes the given io.ReadCloser and returns a decoded stream.
+// NewDecoder decodes the given io.Reader and returns a decoded stream.
 //
 // The stream is always formatted as 16bit (little endian) 2 channels
 // even if the source is single channel MP3.
 // Thus, a sample always consists of 4 bytes.
-func NewDecoder(r io.ReadCloser) (*Decoder, error) {
+func NewDecoder(r io.Reader) (*Decoder, error) {
 	s := &source{
 		reader: r,
 	}

fuzzing_test.go

@@ -19,14 +19,6 @@ import (
 	"testing"
 )
 
-type bytesReadCloser struct {
-	*bytes.Reader
-}
-
-func (b *bytesReadCloser) Close() error {
-	return nil
-}
-
 func TestFuzzing(t *testing.T) {
 	inputs := []string{
 		// #3
@@ -109,7 +101,7 @@ func TestFuzzing(t *testing.T) {
 			"0000000000000",
 	}
 	for _, input := range inputs {
-		b := &bytesReadCloser{bytes.NewReader([]byte(input))}
+		b := bytes.NewReader([]byte(input))
 		_, _ = NewDecoder(b)
 	}
 }

source.go

@@ -19,7 +19,7 @@ import (
 )
 
 type source struct {
-	reader io.ReadCloser
+	reader io.Reader
 	buf    []byte
 	pos    int64
 }
@@ -38,11 +38,6 @@ func (s *source) Seek(position int64, whence int) (int64, error) {
 	return n, nil
 }
 
-func (s *source) Close() error {
-	s.buf = nil
-	return s.reader.Close()
-}
-
 func (s *source) skipTags() error {
 	buf := make([]byte, 3)
 	if _, err := s.ReadFull(buf); err != nil {