<?php
/*
Queue class
Version 1.0
by Johan De Klerk

Description:
Class for implementing a queue data structure
queues are first in first out

Log:
2003/09/26: class created
2003/09/30: by Johan De Klerk:
				currentKey() function added
				replaceElement($element) function added
				removeElement() function added
*/

class Queue {

	var $q_array = array();

	function push($object) {
		array_push($this->q_array,$object);
	}

	function pop() {
		if ($this->size() != 0) {
			return array_shift($this->q_array);
		}
		else {
			return false;
		}
	}

	function element($no) {
		return $this->q_array[$no];
	}

	function firstElement() {
		return reset($this->q_array);
	}

	function nextElement() {
		return next($this->q_array);
	}

	function prevElement() {
		return prev($this->q_array);
	}

	function replaceElement($element) {
		$key = $this->currentKey();
		$this->q_array[$key] = $element;
	}

	function removeElement() {
		$key = $this->currentKey();
		unset($this->q_array[$key]);
	}

	function currentElement() {
		return current($this->q_array);
	}

	function currentKey() {
		return key($this->q_array);
	}

	function size() {
		return sizeof($this->q_array);
	}
}
?>