<?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.
 */

/**
 * An abstract means of writing data.
 * Classes implementing this interface may use a subsystem which requires less
 * memory than working with large strings of data.
 * @package Swift
 * @subpackage ByteStream
 * @author Chris Corbyn
 */
interface Swift_InputByteStream
{
  
  /**
   * Writes $bytes to the end of the stream.
   * 
   * Writing may not happen immediately if the stream chooses to buffer.  If
   * you want to write these bytes with immediate effect, call {@link commit()}
   * after calling write().
   * 
   * This method returns the sequence ID of the write (i.e. 1 for first, 2 for
   * second, etc etc).
   *
   * @param string $bytes
   * @return int
   * @throws Swift_IoException
   */
  public function write($bytes);
  
  /**
   * For any bytes that are currently buffered inside the stream, force them
   * off the buffer.
   * 
   * @throws Swift_IoException
   */
  public function commit();
  
  /**
   * Attach $is to this stream.
   * The stream acts as an observer, receiving all data that is written.
   * All {@link write()} and {@link flushBuffers()} operations will be mirrored.
   * 
   * @param Swift_InputByteStream $is
   */
  public function bind(Swift_InputByteStream $is);
  
  /**
   * Remove an already bound stream.
   * If $is is not bound, no errors will be raised.
   * If the stream currently has any buffered data it will be written to $is
   * before unbinding occurs.
   * 
   * @param Swift_InputByteStream $is
   */
  public function unbind(Swift_InputByteStream $is);
  
  /**
   * Flush the contents of the stream (empty it) and set the internal pointer
   * to the beginning.
   * @throws Swift_IoException
   */
  public function flushBuffers();
  
}
