<?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.

 */

/**

 * Handles RFC 2231 specified Encoding in Swift Mailer.

 * @package Swift

 * @subpackage Encoder

 * @author Chris Corbyn

 */

class Swift_Encoder_Rfc2231Encoder implements Swift_Encoder

{

  /**

   * A character stream to use when reading a string as characters instead of bytes.

   * @var Swift_CharacterStream

   * @access private

   */

  private $_charStream;

  /**

   * Creates a new Rfc2231Encoder using the given character stream instance.

   * @param Swift_CharacterStream

   */

  public function __construct(Swift_CharacterStream $charStream)

  {

    $this->_charStream = $charStream;

  }

  /**

   * Takes an unencoded string and produces a string encoded according to

   * RFC 2231 from it.

   * @param string $string to encode

   * @param int $firstLineOffset

   * @param int $maxLineLength, optional, 0 indicates the default of 75 bytes

   * @return string

   */

  public function encodeString($string, $firstLineOffset = 0,

    $maxLineLength = 0)

  {

    $lines = array(); $lineCount = 0;

    $lines[] = '';

    $currentLine =& $lines[$lineCount++];

    if (0 >= $maxLineLength)

    {

      $maxLineLength = 75;

    }

    $this->_charStream->flushContents();

    $this->_charStream->importString($string);

    $thisLineLength = $maxLineLength - $firstLineOffset;

    while (false !== $char = $this->_charStream->read(4))

    {

      $encodedChar = rawurlencode($char);

      if (0 != strlen($currentLine)

        && strlen($currentLine . $encodedChar) > $thisLineLength)

      {

        $lines[] = '';

        $currentLine =& $lines[$lineCount++];

        $thisLineLength = $maxLineLength;

      }

      $currentLine .= $encodedChar;

    }

    return implode("\r\n", $lines);

  }

  /**

   * Updates the charset used.

   * @param string $charset

   */

  public function charsetChanged($charset)

  {

    $this->_charStream->setCharacterSet($charset);

  }

}