Fix panic on empty lines

reader.go

@@ -272,6 +272,10 @@ func decodeLineOfMasterPlaylist(p *MasterPlaylist, state *decodingState, line st
 
 	line = strings.TrimSpace(line)
 
+	if line == "" {
+		return nil
+	}
+
 	// check for custom tags first to allow custom parsing of existing tags
 	if p.Custom != nil {
 		for _, v := range p.customDecoders {
@@ -451,6 +455,10 @@ func decodeLineOfMediaPlaylist(p *MediaPlaylist, wv *WV, state *decodingState, l
 
 	line = strings.TrimSpace(line)
 
+	if line == "" {
+		return nil
+	}
+
 	// check for custom tags first to allow custom parsing of existing tags
 	if p.Custom != nil {
 		for _, v := range p.customDecoders {

reader_test.go

@@ -344,6 +344,7 @@ func TestDecodeMediaPlaylistExtInfNonStrict2(t *testing.T) {
 #EXT-X-VERSION:3
 #EXT-X-MEDIA-SEQUENCE:0
 %s
+path
 `
 
 	tests := []struct {
@@ -383,6 +384,7 @@ func TestDecodeMediaPlaylistExtInfNonStrict2(t *testing.T) {
 		if err != nil {
 			t.Errorf("unexpected error: %v", err)
 		}
+		test.wantSegment.URI = "path"
 		if !reflect.DeepEqual(p.Segments[0], test.wantSegment) {
 			t.Errorf("\nhave: %+v\nwant: %+v", p.Segments[0], test.wantSegment)
 		}
@@ -972,6 +974,25 @@ func TestDecodeMediaPlaylistStartTime(t *testing.T) {
 	}
 }
 
+func TestDecodeMediaPlaylistDicontinuityAtBegin(t *testing.T) {
+	f, err := os.Open("sample-playlists/media-with-discontinuity-at-start.m3u8")
+	if err != nil {
+		t.Fatal(err)
+	}
+	p, listType, err := DecodeFrom(bufio.NewReader(f), true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	pp := p.(*MediaPlaylist)
+	CheckType(t, pp)
+	if listType != MEDIA {
+		t.Error("Sample not recognized as media playlist.")
+	}
+	if pp.StartTime != float64(0.0) {
+		t.Errorf("Media segment StartTime != 0: %f", pp.StartTime)
+	}
+}
+
 /****************
  *  Benchmarks  *
  ****************/

sample-playlists/media-with-discontinuity-at-start.m3u8

@@ -0,0 +1,13 @@
+#EXTM3U
+#EXT-X-VERSION:5
+#EXT-X-MEDIA-SEQUENCE:0
+#EXT-X-TARGETDURATION:7
+#EXT-X-PLAYLIST-TYPE:VOD
+#EXT-X-KEY:METHOD=AES-128,URI="data:text/plain;charset=utf-8,a4cd9995a1aa91e1",IV=0x30303030303030303030303030303030
+
+#EXT-X-DISCONTINUITY
+
+#EXT-X-PROGRAM-DATE-TIME:1979-05-02T13:33:23.089999973Z
+#EXTINF:6.910,
+294500000/294500000/6778687.ts
+#EXT-X-ENDLIST