<?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';
  }
  
}
