original_string: protected function convertEncoding($string, $to, $from)
      {
          $result = '';
          if (function_exists('iconv')) {
              $result = iconv($from, $to, $string);
          } elseif (function_exists('mb_convert_encoding')) {
              $result = mb_convert_encoding($string, $to, $from);
          } else {
              throw new \RuntimeException(
                  get_class($this)
                  . ' requires either the iconv or mbstring extension to be installed'
                  . ' when escaping for non UTF-8 strings.'
              );
          }
  
          if ($result === false) {
              return ''; // return non-fatal blank string on encoding errors from users
          }
          return $result;
      }
code: protected function convertEncoding($string, $to, $from)
      {
          $result = '';
          if (function_exists('iconv')) {
              $result = iconv($from, $to, $string);
          } elseif (function_exists('mb_convert_encoding')) {
              $result = mb_convert_encoding($string, $to, $from);
          } else {
              throw new \RuntimeException(
                  get_class($this)
                  . ' requires either the iconv or mbstring extension to be installed'
                  . ' when escaping for non UTF-8 strings.'
              );
          }
  
          if ($result === false) {
              return ''; // return non-fatal blank string on encoding errors from users
          }
          return $result;
      }
code_tokens: protected function convertEncoding ( $ string , $ to , $ from ) { $ result = '' ; if ( function_exists ( 'iconv' ) ) { $ result = iconv ( $ from , $ to , $ string ) ; } elseif ( function_exists ( 'mb_convert_encoding' ) ) { $ result = mb_convert_encoding ( $ string , $ to , $ from ) ; } else { throw new \ RuntimeException ( get_class ( $ this ) . ' requires either the iconv or mbstring extension to be installed' . ' when escaping for non UTF-8 strings.' ) ; } if ( $ result === false ) { return '' ; // return non-fatal blank string on encoding errors from users } return $ result ; }
docstring: Encoding conversion helper which wraps iconv and mbstring where they exist or throws
  and exception where neither is available.
  
  @param string $string
  @param string $to
  @param array|string $from
  @throws \RuntimeException
  @return string
docstring_tokens: Encoding conversion helper which wraps iconv and mbstring where they exist or throws and exception where neither is available .