<?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 Transfer Encoding in Swift Mailer.

 * @package Swift

 * @subpackage Mime

 * @author Chris Corbyn

 */

class Swift_Mime_ContentEncoder_Base64ContentEncoder

  extends Swift_Encoder_Base64Encoder

  implements Swift_Mime_ContentEncoder

{

  /**

   * Encode stream $in to stream $out.

   * @param Swift_OutputByteStream $in

   * @param Swift_InputByteStream $out

   * @param int $firstLineOffset

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

   */

  public function encodeByteStream(

    Swift_OutputByteStream $os, Swift_InputByteStream $is, $firstLineOffset = 0,

    $maxLineLength = 0)

  {

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

    {

      $maxLineLength = 76;

    }

    $remainder = 0;

    while (false !== $bytes = $os->read(8190))

    {

      $encoded = base64_encode($bytes);

      $encodedTransformed = '';

      $thisMaxLineLength = $maxLineLength - $remainder - $firstLineOffset;

      while ($thisMaxLineLength < strlen($encoded))

      {

        $encodedTransformed .= substr($encoded, 0, $thisMaxLineLength) . "\r\n";

        $firstLineOffset = 0;

        $encoded = substr($encoded, $thisMaxLineLength);

        $thisMaxLineLength = $maxLineLength;

        $remainder = 0;

      }

      if (0 < $remainingLength = strlen($encoded))

      {

        $remainder += $remainingLength;

        $encodedTransformed .= $encoded;

        $encoded = null;

      }

      $is->write($encodedTransformed);

    }

  }

  /**

   * Get the name of this encoding scheme.

   * Returns the string 'base64'.

   * @return string

   */

  public function getName()

  {

    return 'base64';

  }

}