<?php

/** @file recursivedualiterator.inc
 * @ingroup Examples
 * @brief class RecursiveDualIterator
 * @author  Marcus Boerger
 * @date    2003 - 2006
 *
 * SPL - Standard PHP Library
 */

/** @ingroup Examples
 * @brief   Synchronous iteration over two recursive iterators
 * @author  Marcus Boerger
 * @version 1.0
 */
class RecursiveDualIterator extends DualIterator implements RecursiveIterator
{
	private $ref;

	/** construct iterator from two RecursiveIterator instances
	 *
	 * @param lhs   Left  Hand Side Iterator
	 * @param rhs   Right Hand Side Iterator
	 * @param flags iteration flags
	 */
	function __construct(RecursiveIterator $lhs, RecursiveIterator $rhs, 
				$flags = 0x33 /*DualIterator::DEFAULT_FLAGS*/)
	{
		parent::__construct($lhs, $rhs, $flags);
	}

	/** @return whether both LHS and RHS have children
	 */
	function hasChildren()
	{
		return $this->getLHS()->hasChildren() && $this->getRHS()->hasChildren();	
	}

	/** @return new RecursiveDualIterator (late binding) for the two inner 
	 * iterators current children.
	 */
	function getChildren()
	{
		if (empty($this->ref))
		{
			$this->ref = new ReflectionClass($this);
		}
		return $this->ref->newInstance(
					$this->getLHS()->getChildren(), $this->getRHS()->getChildren(), $this->getFlags());
	}

	/** @return whether both inner iterators are valid, have same hasChildren()
	 * state and identical current and key values or both are non valid.
	 */
	function areIdentical()
	{
		return $this->getLHS()->hasChildren() === $this->getRHS()->hasChildren()
			&& parent::areIdentical();
	}

	/** @return whether both inner iterators are valid, have same hasChildren()
	 * state and equal current and key values or both are invalid.
	 */
	function areEqual()
	{
		return $this->getLHS()->hasChildren() === $this->getRHS()->hasChildren()
			&& parent::areEqual();
	}
}

?>
