<?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) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id$
*/


/**
* PDF file trailer
*
* @package Zend_Pdf
* @copyright Copyright (c) 2005-2015 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();
}