<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * Processes bytes as they pass through a stream and performs filtering.
 * @package Swift
 * @author Chris Corbyn
 */
interface Swift_StreamFilter
{
  
  /**
   * Based on the buffer given, this returns true if more buffering is needed.
   * @param mixed $buffer
   * @return boolean
   */
  public function shouldBuffer($buffer);
  
  /**
   * Filters $buffer and returns the changes.
   * @param mixed $buffer
   * @return mixed
   */
  public function filter($buffer);
  
}