original_string: public function listUniqueIdentifiers( $msgNum = null )
      {
          if ( $this->state != self::STATE_TRANSACTION )
          {
              throw new ezcMailTransportException( "Can't call ListUniqueIdentifiers() on the POP3 transport when not successfully logged in." );
          }
  
          // send the command
          $result = array();
          if ( $msgNum !== null )
          {
              $this->connection->sendData( "UIDL {$msgNum}" );
              $response = $this->connection->getLine( true );
              if ( $this->isPositiveResponse( $response ) )
              {
                  // get the single response line from the server
                  list( $dummy, $num, $id ) = explode( ' ', $response );
                  $result[(int)$num] = $id;
              }
              else
              {
                  throw new ezcMailTransportException( "The POP3 server sent a negative response to the UIDL command: {$response}." );
              }
          }
          else
          {
              $this->connection->sendData( "UIDL" );
              $response = $this->connection->getLine();
              if ( $this->isPositiveResponse( $response ) )
              {
                  // fetch each of the result lines and add it to the result
                  while ( ( $response = $this->connection->getLine( true ) ) !== "." )
                  {
                      list( $num, $id ) = explode( ' ', $response );
                      $result[(int)$num] = $id;
                  }
              }
              else
              {
                  throw new ezcMailTransportException( "The POP3 server sent a negative response to the UIDL command: {$response}." );
              }
          }
          return $result;
      }
code: public function listUniqueIdentifiers( $msgNum = null )
      {
          if ( $this->state != self::STATE_TRANSACTION )
          {
              throw new ezcMailTransportException( "Can't call ListUniqueIdentifiers() on the POP3 transport when not successfully logged in." );
          }
  
          // send the command
          $result = array();
          if ( $msgNum !== null )
          {
              $this->connection->sendData( "UIDL {$msgNum}" );
              $response = $this->connection->getLine( true );
              if ( $this->isPositiveResponse( $response ) )
              {
                  // get the single response line from the server
                  list( $dummy, $num, $id ) = explode( ' ', $response );
                  $result[(int)$num] = $id;
              }
              else
              {
                  throw new ezcMailTransportException( "The POP3 server sent a negative response to the UIDL command: {$response}." );
              }
          }
          else
          {
              $this->connection->sendData( "UIDL" );
              $response = $this->connection->getLine();
              if ( $this->isPositiveResponse( $response ) )
              {
                  // fetch each of the result lines and add it to the result
                  while ( ( $response = $this->connection->getLine( true ) ) !== "." )
                  {
                      list( $num, $id ) = explode( ' ', $response );
                      $result[(int)$num] = $id;
                  }
              }
              else
              {
                  throw new ezcMailTransportException( "The POP3 server sent a negative response to the UIDL command: {$response}." );
              }
          }
          return $result;
      }
code_tokens: public function listUniqueIdentifiers ( $ msgNum = null ) { if ( $ this -> state != self :: STATE_TRANSACTION ) { throw new ezcMailTransportException ( "Can't call ListUniqueIdentifiers() on the POP3 transport when not successfully logged in." ) ; } // send the command $ result = array ( ) ; if ( $ msgNum !== null ) { $ this -> connection -> sendData ( "UIDL {$msgNum}" ) ; $ response = $ this -> connection -> getLine ( true ) ; if ( $ this -> isPositiveResponse ( $ response ) ) { // get the single response line from the server list ( $ dummy , $ num , $ id ) = explode ( ' ' , $ response ) ; $ result [ ( int ) $ num ] = $ id ; } else { throw new ezcMailTransportException ( "The POP3 server sent a negative response to the UIDL command: {$response}." ) ; } } else { $ this -> connection -> sendData ( "UIDL" ) ; $ response = $ this -> connection -> getLine ( ) ; if ( $ this -> isPositiveResponse ( $ response ) ) { // fetch each of the result lines and add it to the result while ( ( $ response = $ this -> connection -> getLine ( true ) ) !== "." ) { list ( $ num , $ id ) = explode ( ' ' , $ response ) ; $ result [ ( int ) $ num ] = $ id ; } } else { throw new ezcMailTransportException ( "The POP3 server sent a negative response to the UIDL command: {$response}." ) ; } } return $ result ; }
docstring: Returns the unique identifiers for messages on the POP3 server.
  
  You can fetch the unique identifier for a specific message by providing
  the $msgNum parameter.
  
  The unique identifier can be used to recognize mail from servers
  between requests. In contrast to the message numbers the unique numbers
  assigned to an email usually never changes.
  
  Note: POP3 servers are not required to support this command and it may fail.
  
  The format of the returned array is:
  <code>
  array( message_num => unique_id );
  </code>
  
  Before calling this method, a connection to the POP3 server must be
  established and a user must be authenticated successfully.
  
  Example:
  <code>
  array( 1 => '000001fc4420e93a', 2 => '000001fd4420e93a' );
  </code>
  
  @throws ezcMailTransportException
  if there was no connection to the server
  or if not authenticated
  or if the server sent a negative response
  @param int $msgNum
  @return array(string)
docstring_tokens: Returns the unique identifiers for messages on the POP3 server .