<?php

/**

 * Zend Framework

 *

 * LICENSE

 *

 * This source file is subject to the new BSD license that is bundled

 * with this package in the file LICENSE.txt.

 * It is also available through the world-wide-web at this URL:

 * http://framework.zend.com/license/new-bsd

 * If you did not receive a copy of the license and are unable to

 * obtain it through the world-wide-web, please send an email

 * to license@zend.com so we can send you a copy immediately.

 *

 * @category   Zend

 * @package    Zend_Pdf

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 * @version    $Id: Trailer.php 20096 2010-01-06 02:05:09Z bkarwin $

 */

/**

 * PDF file trailer

 *

 * @package    Zend_Pdf

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

abstract class Zend_Pdf_Trailer

{

    private static $_allowedKeys = array('Size', 'Prev', 'Root', 'Encrypt', 'Info', 'ID', 'Index', 'W', 'XRefStm', 'DocChecksum');

    /**

     * Trailer dictionary.

     *

     * @var Zend_Pdf_Element_Dictionary

     */

    private $_dict;

    /**

     * Check if key is correct

     *

     * @param string $key

     * @throws Zend_Pdf_Exception

     */

    private function _checkDictKey($key)

    {

        if ( !in_array($key, self::$_allowedKeys) ) {

            /** @todo Make warning (log entry) instead of an exception */

            require_once 'Zend/Pdf/Exception.php';

            throw new Zend_Pdf_Exception("Unknown trailer dictionary key: '$key'.");

        }

    }

    /**

     * Object constructor

     *

     * @param Zend_Pdf_Element_Dictionary $dict

     */

    public function __construct(Zend_Pdf_Element_Dictionary $dict)

    {

        $this->_dict   = $dict;

        foreach ($this->_dict->getKeys() as $dictKey) {

            $this->_checkDictKey($dictKey);

        }

    }

    /**

     * Get handler

     *

     * @param string $property

     * @return mixed

     */

    public function __get($property)

    {

        return $this->_dict->$property;

    }

    /**

     * Set handler

     *

     * @param string $property

     * @param  mixed $value

     */

    public function __set($property, $value)

    {

        $this->_checkDictKey($property);

        $this->_dict->$property = $value;

    }

    /**

     * Return string trailer representation

     *

     * @return string

     */

    public function toString()

    {

        return "trailer\n" . $this->_dict->toString() . "\n";

    }

    /**

     * Get length of source PDF

     *

     * @return string

     */

    abstract public function getPDFLength();

    /**

     * Get PDF String

     *

     * @return string

     */

    abstract public function getPDFString();

    /**

     * Get header of free objects list

     * Returns object number of last free object

     *

     * @return integer

     */

    abstract public function getLastFreeObject();

}