<?php
/**
 * CStackIterator class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright 2008-2013 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CStackIterator implements an iterator for {@link CStack}.
 *
 * It allows CStack to return a new iterator for traversing the items in the stack.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package system.collections
 * @since 1.0
 */
class CStackIterator implements Iterator
{
	/**
	 * @var array the data to be iterated through
	 */
	private $_d;
	/**
	 * @var integer index of the current item
	 */
	private $_i;
	/**
	 * @var integer count of the data items
	 */
	private $_c;

	/**
	 * Constructor.
	 * @param array $data the data to be iterated through
	 */
	public function __construct(&$data)
	{
		$this->_d=&$data;
		$this->_i=0;
		$this->_c=count($this->_d);
	}

	/**
	 * Rewinds internal array pointer.
	 * This method is required by the interface Iterator.
	 */
	public function rewind()
	{
		$this->_i=0;
	}

	/**
	 * Returns the key of the current array item.
	 * This method is required by the interface Iterator.
	 * @return integer the key of the current array item
	 */
	public function key()
	{
		return $this->_i;
	}

	/**
	 * Returns the current array item.
	 * This method is required by the interface Iterator.
	 * @return mixed the current array item
	 */
	public function current()
	{
		return $this->_d[$this->_i];
	}

	/**
	 * Moves the internal pointer to the next array item.
	 * This method is required by the interface Iterator.
	 */
	public function next()
	{
		$this->_i++;
	}

	/**
	 * Returns whether there is an item at current position.
	 * This method is required by the interface Iterator.
	 * @return boolean
	 */
	public function valid()
	{
		return $this->_i<$this->_c;
	}
}
