<?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();
}
