<?php

/**
 * Basic Stack Class.
 *
 * Created for use with eqEOS. May eventually be replaced with native
 * PHP functions `array_pop()`, `array_push()`, and `end()`
 *
 * @author Jon Lawrence <jlawrence11@gmail.com>
 * @copyright Copyright ©2005-2013 Jon Lawrence
 * @license http://opensource.org/licenses/LGPL-2.1 LGPL 2.1 License
 * @package Math
 * @subpackage EOS
 * @version 2.0
 */
class phpStack {
	private $index;
	private $locArray;

	/**
	 * Constructor
	 *
	 * Initializes the stack
	 */
	public function __construct() {
		//define the private vars
		$this->locArray = array();
		$this->index = -1;
	}

	/**
	 * Peek
	 *
	 * Will view the last element of the stack without removing it
	 *
	 * @return Mixed An element of the array or false if none exist
	 */
	public function peek() {
		if($this->index > -1)
			return $this->locArray[$this->index];
		else
			return false;
	}

	/**
	 * Poke
	 *
	 * Will add an element to the end of the stack
	 *
	 * @param Mixed Element to add
	 */
	public function poke($data) {
		$this->locArray[++$this->index] = $data;
	}

	/**
	 * Push
	 *
	 * Alias of {@see phpStack::poke()}
	 * Adds element to the stack
	 *
	 * @param Mixed Element to add
	 */
	public function push($data) {
		//allias for 'poke'
		$this->poke($data);
	}

	/**
	 * Pop
	 *
	 * Retrives an element from the end of the stack, and removes it from
	 * the stack at the same time. If no elements, returns boolean false
	 *
	 * @return Mixed Element at end of stack or false if none exist
	 */
	public function pop() {
		if($this->index > -1)
		{
			$this->index--;
			return $this->locArray[$this->index+1];
		}
		else
			return false;
	}

	/**
	 * Clear
	 *
	 * Clears the stack to be reused.
	 */
	public function clear() {
		$this->index = -1;
		$this->locArray = array();
	}

	/**
	 * Get Stack
	 *
	 * Returns the array of stack elements, keeping all, indexed at 0
	 *
	 * @return Mixed Array of stack elements or false if none exist.
	 */
	public function getStack() {
		if($this->index > -1)
		{
			return array_values($this->locArray);
		}
		else
			return false;
	}
}

?>