<?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.

 *

 * @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

     */

    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

     * @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);

    }



    /**

     * Make a deep copy of object.

     */

    public function __clone()

    {

        $this->_charStream = clone $this->_charStream;

    }

}