Replace invalid utf-8 characters with underscores. Bump cache version.

stepmania/src/SongCacheIndex.cpp

@@ -34,8 +34,16 @@ RString SongCacheIndex::GetCacheFilePath( const RString &sGroup, const RString &
 	/* Don't use GetHashForFile, since we don't want to spend time
 	 * checking the file size and date. */
 	RString s = sPath;
-	s.Replace( '/', '_' );
-	return ssprintf( "%s/%s/%s", SpecialFiles::CACHE_DIR.c_str(), sGroup.c_str(), s.c_str() );
+	/* Change slashes and invalid utf-8 characters to _.
+	 * http://en.wikipedia.org/wiki/UTF-8
+	 * Mac OS X doesn't support precomposed unicode characters in files names and
+	 * so we should probably replace them with combining diacritics.
+	 * XXX How do we do this and is it even worth it? */
+	const char *invalid = "/\xc0\xc1\xfe\xff\xf8\xf9\xfa\xfb\xfc\xfd\xf5\xf6\xf7";
+	for( size_t pos = s.find_first_of(invalid); pos != RString::npos; pos = s.find_first_of(invalid, pos) )
+		s[pos] = '_';
+	// CACHE_DIR ends with a /.
+	return ssprintf( "%s%s/%s", SpecialFiles::CACHE_DIR.c_str(), sGroup.c_str(), s.c_str() );
 }
 
 SongCacheIndex::SongCacheIndex()