<?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.
 */

//@require 'Swift/Mime/ContentEncoder.php';
//@require 'Swift/Encoder/QpEncoder.php';
//@require 'Swift/InputByteStrean.php';
//@require 'Swift/OutputByteStream.php';
//@require 'Swift/CharacterStream.php';

/**
 * Handles Quoted Printable (QP) Transfer Encoding in Swift Mailer.
 * @package Swift
 * @subpackage Mime
 * @author Chris Corbyn
 */
class Swift_Mime_ContentEncoder_QpContentEncoder extends Swift_Encoder_QpEncoder
  implements Swift_Mime_ContentEncoder
{

  /**
   * Creates a new QpContentEncoder for the given CharacterStream.
   * @param Swift_CharacterStream $charStream to use for reading characters
   * @param Swift_StreamFilter $filter if canonicalization should occur
   */
  public function __construct(Swift_CharacterStream $charStream,
    Swift_StreamFilter $filter = null)
  {
    parent::__construct($charStream, $filter);
  }

  /**
   * Encode stream $in to stream $out.
   * QP encoded strings have a maximum line length of 76 characters.
   * If the first line needs to be shorter, indicate the difference with
   * $firstLineOffset.
   * @param Swift_OutputByteStream $os output stream
   * @param Swift_InputByteStream $is input stream
   * @param int $firstLineOffset
   * @param int $maxLineLength
   */
  public function encodeByteStream(
    Swift_OutputByteStream $os, Swift_InputByteStream $is, $firstLineOffset = 0,
    $maxLineLength = 0)
  {
    if ($maxLineLength > 76 || $maxLineLength <= 0)
    {
      $maxLineLength = 76;
    }

    $thisLineLength = $maxLineLength - $firstLineOffset;

    $this->_charStream->flushContents();
    $this->_charStream->importByteStream($os);
    
    $currentLine = '';
    $prepend = '';
    $size=$lineLen=0;

    while (false !== $bytes = $this->_nextSequence())
    {
      //If we're filtering the input
      if (isset($this->_filter))
      {
        //If we can't filter because we need more bytes
        while ($this->_filter->shouldBuffer($bytes))
        {
          //Then collect bytes into the buffer
          if (false === $moreBytes = $this->_nextSequence(1))
          {
            break;
          }

          foreach ($moreBytes as $b)
          {
            $bytes[] = $b;
          }
        }
        //And filter them
        $bytes = $this->_filter->filter($bytes);
      }

      $enc = $this->_encodeByteSequence($bytes, $size);
      if ($currentLine && $lineLen+$size >= $thisLineLength)
      {
        $is->write($prepend . $this->_standardize($currentLine));
        $currentLine = '';
        $prepend = "=\r\n";
        $thisLineLength = $maxLineLength;
        $lineLen=0;
      }
      $lineLen+=$size;
      $currentLine .= $enc;
    }
    if (strlen($currentLine))
    {
      $is->write($prepend . $this->_standardize($currentLine));
    }
  }

  /**
   * Get the name of this encoding scheme.
   * Returns the string 'quoted-printable'.
   * @return string
   */
  public function getName()
  {
    return 'quoted-printable';
  }

}
