LISTE DOUBLEMENT CHAÎNÉE (PHP5)

<?php
// node.php
class TNode {
	public $nextPtr;		// Node *
	public $prevPtr;		// Node *
	public $currentPtr;		// Value

	function __construct($value) {
		$this->prevPtr = NULL;
		$this->nextPtr = NULL;
		$this->currentPtr = $value;
	}

	function __destruct() {
		$this->currentPtr = NULL;
	}
};
?>

<?php
// list.php
include_once "node.php";

class TList {
	private $currentPtr;	// TNode

	function __construct() {
		$this->currentPtr = NULL;
	}

	function __destruct() {
		$this->DeleteAll();
	}

	/**
	 * @return bool
	 * @desc Deletes all Nodes
	*/
	public function DeleteAll() {
		if( !$this->isEmpty() ) {
			// We remove Circular loop
			$this->currentPtr->prevPtr->nextPtr = NULL;

			// We crate a temp
			$tempPtr = NULL;
			while( $this->currentPtr !== NULL ) {
				// We save the actual position
				$tempPtr = $this->currentPtr;
				// We move our current
				$this->currentPtr = $this->currentPtr->nextPtr;
				// We delete the space before current
				$tempPtr = NULL;
			}
			// Reseting Variable
			$this->currentPtr = NULL;
			return true;
		} else {
			return false;
		}
	}

	/**
	 * @return bool
	 * @desc Removes current Node
	*/
	public function RemoveNode() {
		if( !$this->isEmpty() ) {
			// If the list contains only 1 node
			if( $this->currentPtr->nextPtr === $this->currentPtr) { // === comparing object classes
				$this->currentPtr = NULL;
			} else {
				$tempPtr = NULL;
				$this->currentPtr->prevPtr->nextPtr = $this->currentPtr->nextPtr;
				$this->currentPtr->nextPtr->prevPtr = $this->currentPtr->prevPtr;
				$tempPtr = $this->currentPtr;
				$this->currentPtr = $this->currentPtr->nextPtr;
				$tempPtr = NULL;
			}
			return true;
		}
		return false;
	}

	/**
	 * @return bool
	 * @desc Returns true if the list is empty
	*/
	private function isEmpty() {
		return ($this->currentPtr === NULL);
	}

	/**
	 * @return TNode *
	 * @param mixed $value
	 * @desc Return Pointer to newly allocated node
	*/
	public function getNewNode($value) {
		$ptr = new TNode($value);
		return $ptr;
	}

	/**
	 * @return void
	 * @param mixed $value
	 * @desc Add Node with value
	*/
	public function addNode($value) {
		$newPtr = $this->getNewNode($value);

		// We have to case : Empty list, Non Empty List
		if( $this->isEmpty() ) {
			$newPtr->prevPtr = $newPtr;
			$newPtr->nextPtr = $newPtr;
		} else {
			$newPtr->nextPtr = $this->currentPtr->nextPtr;
			$newPtr->prevPtr = $this->currentPtr;
			$this->currentPtr->nextPtr = $newPtr;
			$newPtr->nextPtr->prevPtr = $newPtr;
		}
		$this->currentPtr = $newPtr;
	}

	/**
	 * @return bool
	 * @desc Move current to the next position
	*/
	public function nextCurrent() {
		if( !$this->isEmpty() ) {
			$this->currentPtr = $this->currentPtr->nextPtr;
			return true;
		} else {
			return false;
		}
	}

	/**
	 * @return bool
	 * @desc Move current to the prev position
	*/
	public function prevCurrent(){
		if( !$this->isEmpty() ) {
			$this->currentPtr = $this->currentPtr->prevPtr;
			return true;
		} else {
			return false;
		}
	}

	/**
	 * @return mixed
	 * @desc Return the value hosted by Node
	*/
	public function &getCurrent() {
		if( !$this->isEmpty() ) {
			return $this->currentPtr->currentPtr;
		} else {
			return NULL;
		}
	}
};
?>

<?php
// example.php
// Normally, all functions are templated. But in PHP,
// it is already templated.

include_once "list.php";
$a = new TList;
$a->addNode(20);	// Add 20
$a->addNode(30);	// Add 30
$a->addNode(40);	// Add 40
$a->addNode(50);	// Add 50
$a->addNode(100);	// Add 100
$a->prevCurrent();	// Select Previous (50)
$a->RemoveNode();	// Remove Current (50). 100 is Selected
$a->nextCurrent();	// Select Next (20)
$a->nextCurrent();	// Select Next (30)
$a->addNode(35);	// Add 35 (next to 30)
$a->nextCurrent();	// Select 40
echo $a->getCurrent();	// Return 40
?>