docs: private String osFriendly(String data) {
          /* Allow only permissable characters to be used in filenames */
  
          String dataCopy = "";
          char c;
          boolean valid;
  
          for (int i = 0; i < data.length(); i++) {
              c = data.charAt(i);
  
              valid = true;
              if ((c > 0x00) && (c < 0x20)) {
                  valid = false;
              }
              if ((c > 0x7E) && (c < 0xA0)) {
                  valid = false;
              }
  
              switch (c) {
                  case '/':
                  case '\\':
                  case '?':
                  case '%':
                  case '*':
                  case ':':
                  case '|':
                  case '"':
                  case '<':
                  case '>':
                  case '.':
                  case ',':
                  case '=':
                  case '+':
                  case ']':
                  case '[':
                  case '!':
                  case '@':
                      valid = false;
              }
  
              if (valid) {
                  dataCopy += c;
              }
  
          }
  
          return dataCopy;
      }