Beatmap downloader improvements and fixes.

Updates:
- Added some buttons to downloads menu: clear inactive downloads, import beatmaps, reset search, and show/hide unranked maps.
- Small changes to OsuParser, OszUnpacker, and OsuGroupList (mostly adding return values) to allow parsing only newly unpacked beatmaps.
- Added alpha fade hover effect to MenuButton, as an alternative to expanding (used for 3-part menu buttons).
- Added text rendering fields to MenuButton (also for the 3-part menu buttons).
- Added sound effects to downloads menu.

Fixes:
- Check downloads for illegal filename characters, and remove them if necessary.
- The number of results and downloads shown now supports all resolutions.
- Confirmation dialog no longer appears when restarting the application (since downloads are static).
- Do not set a focus node immediately if the theme song will be played.
- Always play the theme song if no songs are loaded (even if disabled in settings).

Signed-off-by: Jeffrey Han <itdelatrisu@gmail.com>

src/itdelatrisu/opsu/Utils.java

@@ -28,6 +28,7 @@ import java.io.File;
 import java.nio.ByteBuffer;
 import java.nio.IntBuffer;
 import java.text.SimpleDateFormat;
+import java.util.Arrays;
 import java.util.Date;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -109,6 +110,19 @@ public class Utils {
 	/** Set of all Unicode strings already loaded. */
 	private static HashSet<String> loadedGlyphs = new HashSet<String>();
 
+	/**
+	 * List of illegal filename characters.
+	 * @see #cleanFileName(String, char)
+	 */
+	private final static int[] illegalChars = {
+		34, 60, 62, 124, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
+		11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
+		24, 25, 26, 27, 28, 29, 30, 31, 58, 42, 63, 92, 47
+	};
+	static {
+	    Arrays.sort(illegalChars);
+	}
+
 	// game-related variables
 	private static GameContainer container;
 	private static StateBasedGame game;
@@ -211,7 +225,7 @@ public class Utils {
 		backButton = new MenuButton(back,
 				back.getWidth() / 2f,
 				height - (back.getHeight() / 2f));
-		backButton.setHoverDir(MenuButton.Expand.UP_RIGHT);
+		backButton.setHoverExpand(MenuButton.Expand.UP_RIGHT);
 	}
 
 	/**
@@ -704,4 +718,24 @@ public class Utils {
 		char pre = "KMGTPE".charAt(exp - 1);
 		return String.format("%.1f %cB", bytes / Math.pow(1024, exp), pre);
 	}
+
+	/**
+	 * Cleans a file name.
+	 * @param badFileName the original name string
+	 * @param replace the character to replace illegal characters with (or 0 if none)
+	 * @return the cleaned file name
+	 * @author Sarel Botha (http://stackoverflow.com/a/5626340)
+	 */
+	public static String cleanFileName(String badFileName, char replace) {
+		boolean doReplace = (replace > 0 && Arrays.binarySearch(illegalChars, replace) < 0);
+	    StringBuilder cleanName = new StringBuilder();
+	    for (int i = 0, n = badFileName.length(); i < n; i++) {
+	        int c = badFileName.charAt(i);
+	        if (Arrays.binarySearch(illegalChars, c) < 0)
+	            cleanName.append((char) c);
+	        else if (doReplace)
+	        	cleanName.append(replace);
+	    }
+	    return cleanName.toString();
+	}
 }