original_string: public static function pad($input, $length = 0)
      {
          $input = ltrim($input, '0');
  
          if ($input == '') {
              $input = '0';
          }
  
          return str_pad($input, $length, '0', STR_PAD_LEFT);
      }
code: public static function pad($input, $length = 0)
      {
          $input = ltrim($input, '0');
  
          if ($input == '') {
              $input = '0';
          }
  
          return str_pad($input, $length, '0', STR_PAD_LEFT);
      }
code_tokens: public static function pad ( $ input , $ length = 0 ) { $ input = ltrim ( $ input , '0' ) ; if ( $ input == '' ) { $ input = '0' ; } return str_pad ( $ input , $ length , '0' , STR_PAD_LEFT ) ; }
docstring: Pad left with zeroes to match given length.
  
  @param string $input
  @param int    $length
  
  @return string
docstring_tokens: Pad left with zeroes to match given length .