panic: beep.Loop2 and embedded music files

[hanchon]

Hi,

I was trying the lib and I found an issue with the new beep.Loop2 function while using MP3 files embedded in the code.

Here is the minimal replication

Basically the problem is related to the issue #37, where the .Len() of the file is returning 0 because the deprecated mp3 decoder does not handle correctly embedded files.

The program panics with the following message:

panic: invalid argument to Loop2; start position 0 must be smaller than the source streamer length 0

Using beep.Loop works fine with the mp3 decoder.

I am just opening the issue in case someone else ends up with the same issue, and the possible solution with the current state of the code is:

• Use beep.Loop instead of beep.Loop2

UPDATE: I had a bug in my OGG example, beep.Loop2 also panics for that case.

[hanchon]

So the issue was just the io.NopCloser

file := io.NopCloser(bytes.NewReader(musicBytes))

Adding a no-op Close method to a bytes.Reader works fine:

type myReader struct {
	*bytes.Reader
}

func (f *myReader) Close() error {
	return nil
}

func NewMyReader(data []byte) *myReader {
	return &myReader{
		Reader: bytes.NewReader(data),
	}
}

...

file := NewMyReader(musicBytes)