<?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) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)

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

 * @version    $Id: Reference.php 23775 2011-03-01 17:25:24Z ralph $

 */





/** Internally used classes */

require_once 'Zend/Pdf/Element/Null.php';





/** Zend_Pdf_Element */

require_once 'Zend/Pdf/Element.php';



/**

 * PDF file 'reference' element implementation

 *

 * @category   Zend

 * @package    Zend_Pdf

 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)

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

 */

class Zend_Pdf_Element_Reference extends Zend_Pdf_Element

{

    /**

     * Object value

     * The reference to the object

     *

     * @var mixed

     */

    private $_ref;



    /**

     * Object number within PDF file

     *

     * @var integer

     */

    private $_objNum;



    /**

     * Generation number

     *

     * @var integer

     */

    private $_genNum;



    /**

     * Reference context

     *

     * @var Zend_Pdf_Element_Reference_Context

     */

    private $_context;





    /**

     * Reference to the factory.

     *

     * It's the same as referenced object factory, but we save it here to avoid

     * unnecessary dereferencing, whech can produce cascade dereferencing and parsing.

     * The same for duplication of getFactory() function. It can be processed by __call()

     * method, but we catch it here.

     *

     * @var Zend_Pdf_ElementFactory

     */

    private $_factory;



    /**

     * Object constructor:

     *

     * @param integer $objNum

     * @param integer $genNum

     * @param Zend_Pdf_Element_Reference_Context $context

     * @param Zend_Pdf_ElementFactory $factory

     * @throws Zend_Pdf_Exception

     */

    public function __construct($objNum, $genNum = 0, Zend_Pdf_Element_Reference_Context $context, Zend_Pdf_ElementFactory $factory)

    {

        if ( !(is_integer($objNum) && $objNum > 0) ) {

            require_once 'Zend/Pdf/Exception.php';

            throw new Zend_Pdf_Exception('Object number must be positive integer');

        }

        if ( !(is_integer($genNum) && $genNum >= 0) ) {

            require_once 'Zend/Pdf/Exception.php';

            throw new Zend_Pdf_Exception('Generation number must be non-negative integer');

        }



        $this->_objNum  = $objNum;

        $this->_genNum  = $genNum;

        $this->_ref     = null;

        $this->_context = $context;

        $this->_factory = $factory;

    }



    /**

     * Check, that object is generated by specified factory

     *

     * @return Zend_Pdf_ElementFactory

     */

    public function getFactory()

    {

        return $this->_factory;

    }





    /**

     * Return type of the element.

     *

     * @return integer

     */

    public function getType()

    {

        if ($this->_ref === null) {

            $this->_dereference();

        }



        return $this->_ref->getType();

    }





    /**

     * Return reference to the object

     *

     * @param Zend_Pdf_Factory $factory

     * @return string

     */

    public function toString($factory = null)

    {

        if ($factory === null) {

            $shift = 0;

        } else {

            $shift = $factory->getEnumerationShift($this->_factory);

        }



        return $this->_objNum + $shift . ' ' . $this->_genNum . ' R';

    }





    /**

     * Dereference.

     * Take inderect object, take $value member of this object (must be Zend_Pdf_Element),

     * take reference to the $value member of this object and assign it to

     * $value member of current PDF Reference object

     * $obj can be null

     *

     * @throws Zend_Pdf_Exception

     */

    private function _dereference()

    {

        if (($obj = $this->_factory->fetchObject($this->_objNum . ' ' . $this->_genNum)) === null) {

            $obj = $this->_context->getParser()->getObject(

                           $this->_context->getRefTable()->getOffset($this->_objNum . ' ' . $this->_genNum . ' R'),

                           $this->_context

                                                          );

        }



        if ($obj === null ) {

            $this->_ref = new Zend_Pdf_Element_Null();

            return;

        }



        if ($obj->toString() != $this->_objNum . ' ' . $this->_genNum . ' R') {

            require_once 'Zend/Pdf/Exception.php';

            throw new Zend_Pdf_Exception('Incorrect reference to the object');

        }



        $this->_ref = $obj;

    }



    /**

     * Detach PDF object from the factory (if applicable), clone it and attach to new factory.

     *

     * @param Zend_Pdf_ElementFactory $factory  The factory to attach

     * @param array &$processed  List of already processed indirect objects, used to avoid objects duplication

     * @param integer $mode  Cloning mode (defines filter for objects cloning)

     * @returns Zend_Pdf_Element

     */

    public function makeClone(Zend_Pdf_ElementFactory $factory, array &$processed, $mode)

    {

        if ($this->_ref === null) {

            $this->_dereference();

        }



        // This code duplicates code in Zend_Pdf_Element_Object class,

        // but allows to avoid unnecessary method call in most cases

        $id = spl_object_hash($this->_ref);

        if (isset($processed[$id])) {

            // Do nothing if object is already processed

            // return it

            return $processed[$id];

        }



        return $this->_ref->makeClone($factory, $processed, $mode);

    }



    /**

     * Mark object as modified, to include it into new PDF file segment.

     */

    public function touch()

    {

        if ($this->_ref === null) {

            $this->_dereference();

        }



        $this->_ref->touch();

    }



    /**

     * Return object, which can be used to identify object and its references identity

     *

     * @return Zend_Pdf_Element_Object

     */

    public function getObject()

    {

        if ($this->_ref === null) {

            $this->_dereference();

        }



        return $this->_ref;

    }



    /**

     * Get handler

     *

     * @param string $property

     * @return mixed

     */

    public function __get($property)

    {

        if ($this->_ref === null) {

            $this->_dereference();

        }



        return $this->_ref->$property;

    }



    /**

     * Set handler

     *

     * @param string $property

     * @param  mixed $value

     */

    public function __set($property, $value)

    {

        if ($this->_ref === null) {

            $this->_dereference();

        }



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

    }



    /**

     * Call handler

     *

     * @param string $method

     * @param array  $args

     * @return mixed

     */

    public function __call($method, $args)

    {

        if ($this->_ref === null) {

            $this->_dereference();

        }



        return call_user_func_array(array($this->_ref, $method), $args);

    }



    /**

     * Clean up resources

     */

    public function cleanUp()

    {

        $this->_ref = null;

    }



    /**

     * Convert PDF element to PHP type.

     *

     * @return mixed

     */

    public function toPhp()

    {

        if ($this->_ref === null) {

            $this->_dereference();

        }



        return $this->_ref->toPhp();

    }

}