<?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 Base 64 Encoding in Swift Mailer.

 * @package Swift

 * @subpackage Encoder

 * @author Chris Corbyn

 */

class Swift_Encoder_Base64Encoder implements Swift_Encoder

{

  /**

   * Takes an unencoded string and produces a Base64 encoded string from it.

   * Base64 encoded strings have a maximum line length of 76 characters.

   * If the first line needs to be shorter, indicate the difference with

   * $firstLineOffset.

   * @param string $string to encode

   * @param int $firstLineOffset

   * @param int $maxLineLength, optional, 0 indicates the default of 76 bytes

   * @return string

   */

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

    $maxLineLength = 0)

  {

    if (0 >= $maxLineLength || 76 < $maxLineLength)

    {

      $maxLineLength = 76;

    }

    $encodedString = base64_encode($string);

    $firstLine = '';

    if (0 != $firstLineOffset)

    {

      $firstLine = substr(

        $encodedString, 0, $maxLineLength - $firstLineOffset

        ) . "\r\n";

      $encodedString = substr(

        $encodedString, $maxLineLength - $firstLineOffset

        );

    }

    return $firstLine . trim(chunk_split($encodedString, $maxLineLength, "\r\n"));

  }

  /**

   * Does nothing.

   */

  public function charsetChanged($charset)

  {

  }

}