(30-09-2011, 09:11 AM)niahoo a écrit : Pourquoi vous tenez absolument à ne pas utiliser la récursivité, alors que ça semble très indiqué dans ce cas précis ?

<?php

class Rect

{

	private $width, $height;



	function __construct($width, $height = null){

		$this->width = $width;

		$this->height = $height ?: $width;

	}



	function width(){

		return $this->width;

	}



	function height(){

		return $this->height;

	}



	function size(){

		return $this->height * $this->width;

	}



	function origin(){

		return floor($this->height / 2) * $this->width + floor($this->width / 2);

	}



	function index($x,$y){

		return $x + $y * $this->width;

	}



	function coord($index){

		return array($index % $this->width, $index / $this->width);

	}

}



class Nexter

{

	private $add;



	function __construct($add = 1){

		$this->add = $add;

	}



	function per(&$n){

		$n += $this->add;

	}

}



class SpiralSquareIterator implements Iterator

{

	const TO_RIGHT = 0;

	const TO_DOWN = 1;

	const TO_LEFT = 2;

	const TO_UP = 3;



	private $begin, $it, $end, $circular, $step, $to, $m, $odd, $inner, $nexter;



	function __construct($shape, $begin = null, $end = null, $to = SpiralSquareIterator::TO_RIGHT){

		$this->begin = $begin === null ? $shape->origin() : $begin;

		$this->end = $end ?: self::getEndIndex($to, $shape);

		$h = $shape->height();

		//SplFixedArray ?

		$this->circular = new InfiniteIterator(new ArrayIterator(array(

			new Nexter(1),

			new Nexter($h),

			new Nexter(-1),

			new Nexter(-$h),

		)));

		$this->to = $to;

	}



	static function getEndIndex($to, $shape){

		return $to === SpiralSquareIterator::TO_RIGHT ? $shape->width() - 1 : (

			$to === SpiralSquareIterator::TO_DOWN ? $shape->size() - 1 : (

			$to === SpiralSquareIterator::TO_LEFT ? $shape->height() * ($shape->width() - 1) :

			0));

	}



	function rewind(){

		$this->it = $this->begin;

		$this->circular->rewind();

		for ($n = $this->to; $n--; $this->circular->next());

		$this->m = 1;

		$this->step = 0;

		$this->odd = false;

		$this->inner = false;

		$this->nexter = $this->circular->current();

	}



	function valid(){

		if ($this->inner)

			return false;

		if ($this->it == $this->end)

			$this->inner = true;

		return true;

	}



	function current(){

		return $this->it;

	}



	/**

	 * Retourne l'indice du bord du carré (↑:0, →:1, ↓:2, ←: 3)

	 * @attention la clef étant 0,1,2 ou 3 celle-ci n'est pas unique

	 */

	function key(){

		$r = $this->circular->key();

		return $r === $this->to && !$this->m

			? ($this->to + 1 === 4 ? 0 : $this->to + 1) : $r;

	}



	function next(){

		if (!$this->m--){

			$this->m = ($this->odd = !$this->odd) ? $this->step : ++$this->step;

			$this->circular->next();

			$this->nexter = $this->circular->current();

		}

		$this->nexter->per($this->it);

	}



	/**

	 * @param bool $get_pair = false : si true la valeur est une pair avec comme premier

	 *  indice la clef de l'itérateur

	 * @param bool $calculate_distance = true : si true l'itérateur sert de clef et la valeur

	 *  et la distance par rapport au centre de la spiral

	 *

	 * $get_pair = false & $calculate_distance = false : $r[] = $this->current()

	 * $get_pair = true & $calculate_distance = false : $r[] = array($this->key(), $this->current())

	 * $get_pair = false & $calculate_distance = true : $r[$this->current()] = $n++

	 * $get_pair = true & $calculate_distance = true: $r[$this->current()] = array($this->key(), $n++)

	 */

	function toArray($get_pair = false, $calculate_distance = true){

		$r = array();

		$this->rewind();

		if ($calculate_distance) {

			$n = 0;

			if ($get_pair){

				while ($this->it != $this->end){

					$r[$this->it] = array($this->key(), $n++);

					$this->next();

				}

				$r[$this->it] = array($this->key(), $n++);

			} else {

				while ($this->it != $this->end){

					$r[$this->it] = $n++;

					$this->next();

				}

				$r[$this->it] = $n++;

			}

		}

		else if ($get_pair){

			while ($this->it != $this->end){

				$r[] = array($this->key(), $this->it);

				$this->next();

			}

			$r[] = array($this->key(), $this->it);

		} else {

			while ($this->it != $this->end){

				$r[] = $this->it;

				$this->next();

			}

			$r[] = $this->it;

		}

		return $r;

	}

}



function spiral_square($shape, $begin = null, $end = null, $to = SpiralSquareIterator::TO_RIGHT,

				$get_pair = false, $calculate_distance = true)

{

	$it = new SpiralSquareIterator($shape, $begin, $end, $to);

	return $it->toArray($get_pair, $calculate_distance);

}



$square = new Rect(17);

$indices = spiral_square($square, null, null, SpiralSquareIterator::TO_RIGHT, true);

/*$indices = array();

$n = 0;

foreach(new SpiralSquareIterator($square) as $border => $i){

	$indices[$i] = array($border, $n++);

}*/



//var_dump(iterator_to_array(new SpiralSquareIterator($square), false));

//var_dump($indices);



$c = array('#00D', '#000', '#D00', '#0D0');



echo '<table border=1>';

for ($i = 0, $end = $square->size(); $i != $end; )

{

	echo '<tr>';

	for ($endx = $i + $square->width(); $i != $endx; ++$i)

	{

		echo isset($indices[$i])

			? '<td style="color:'.$c[$indices[$i][0]].'">'.$indices[$i][1].'</td>'

			: '<td style="color:darkorange">'.$i.'</td>';

	}

	echo '</tr>';

}

echo '</table>';