code: private static int skipWhitespace(String input, int pos) {
          for (; pos < input.length(); pos++) {
              char c = input.charAt(pos);
              if (c != ' ' && c != '\t') {
                  break;
              }
          }
          return pos;
      }
docs: Returns the next non-whitespace character in {@code input} that is white
  space. Result is undefined if input contains newline characters.