<?php

/*
 Bi-Directional CharacterStream in Swift Mailer.
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 */

require_once dirname(__FILE__) . '/OutputByteStream.php';
require_once dirname(__FILE__) . '/CharacterReaderFactory.php';


/**
 * An abstract means of reading and writing data in terms of characters as opposed
 * to bytes.
 * Classes implementing this interface may use a subsystem which requires less
 * memory than working with large strings of data.
 * @package Swift
 * @subpackage CharacterStream
 * @author Chris Corbyn
 */
interface Swift_CharacterStream
{

  /**
   * Set the character set used in this CharacterStream.
   * @param string $charset
   */
  public function setCharacterSet($charset);
  
  /**
   * Set the CharacterReaderFactory for multi charset support.
   * @param Swift_CharacterReaderFactory $factory
   */
  public function setCharacterReaderFactory(
    Swift_CharacterReaderFactory $factory);
  
  /**
   * Overwrite this character stream using the byte sequence in the byte stream.
   * @param Swift_OutputByteStream $os output stream to read from
   */
  public function importByteStream(Swift_OutputByteStream $os);
  
  /**
   * Import a string a bytes into this CharacterStream, overwriting any existing
   * data in the stream.
   * @param string $string
   */
  public function importString($string);
  
  /**
   * Read $length characters from the stream and move the internal pointer
   * $length further into the stream.
   * @param int $length
   * @return string
   */
  public function read($length);
  
  /**
   * Read $length characters from the stream and return a 1-dimensional array
   * containing there octet values.
   * @param int $length
   * @return int[]
   */
  public function readBytes($length);
  
  /**
   * Write $chars to the end of the stream.
   * @param string $chars
   */
  public function write($chars);
  
  /**
   * Move the internal pointer to $charOffset in the stream.
   * @param int $charOffset
   */
  public function setPointer($charOffset);
  
  /**
   * Empty the stream and reset the internal pointer.
   */
  public function flushContents();
  
}