Add support for txt format

src/main/java/com/github/hhhzzzsss/songplayer/conversion/TxtConverter.java

@@ -0,0 +1,40 @@
+package com.github.hhhzzzsss.songplayer.conversion;
+
+import com.github.hhhzzzsss.songplayer.song.Note;
+import com.github.hhhzzzsss.songplayer.song.Song;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+public class TxtConverter {
+    public static Song getSongFromBytes(byte[] bytes, String fileName) throws IOException {
+        Song song = new Song(fileName);
+        String strContent = new String(bytes, StandardCharsets.UTF_8);
+
+        String[] lines = strContent.split("\\r?\\n");
+        for (int lineNum = 1; lineNum <= lines.length; lineNum++) {
+            String line = lines[lineNum-1].strip();
+
+            if (line.startsWith("#")) continue;
+
+            String[] split = line.split(":");
+            if (split.length != 3) throw new IOException("Invalid format at line " + lineNum);
+            int tick, pitch, instrument;
+            try {
+                tick = Integer.parseInt(split[0]);
+                pitch = Integer.parseInt(split[1]);
+                instrument = Integer.parseInt(split[2]);
+            } catch (NumberFormatException e) {
+                throw new IOException("Invalid format at line " + lineNum);
+            }
+
+            int noteId = pitch + instrument*25;
+            song.add(new Note(noteId, tick*50));
+            song.length = song.get(song.size()-1).time + 50;
+        }
+
+        song.sort();
+
+        return song;
+    }
+}

src/main/java/com/github/hhhzzzsss/songplayer/song/SongLoaderThread.java

@@ -4,6 +4,7 @@ import com.github.hhhzzzsss.songplayer.SongPlayer;
 import com.github.hhhzzzsss.songplayer.Util;
 import com.github.hhhzzzsss.songplayer.conversion.MidiConverter;
 import com.github.hhhzzzsss.songplayer.conversion.NBSConverter;
+import com.github.hhhzzzsss.songplayer.conversion.TxtConverter;
 
 import java.io.IOException;
 import java.net.URL;
@@ -75,6 +76,13 @@ public class SongLoaderThread extends Thread{
 				catch (Exception e) {}
 			}
 
+			if (song == null) {
+				try {
+					song = TxtConverter.getSongFromBytes(bytes, filename);
+				}
+				catch (Exception e) {}
+			}
+
 			if (song == null) {
 				throw new IOException("Invalid song format");
 			}