<?php

class LoopQueue

{

private $MaxSzie;

private $data = [];

private $head = 0;

private $tail = 0;

/**

* 初始化队列大小 最后的位置不存放数据,实际大小 = size++

*/

public function __construct($size = 10)

{

$this->MaxSzie = ++$size;

}

/**

* 队列满条件 ($this->tail+1) % $this->MaxSzie == $this->head

*/

public function enQueue($data)

{

if (($this->tail+1) % $this->MaxSzie == $this->head)

return -1;

$this->data[$this->tail] = $data;

$this->tail = (++$this->tail) % $this->MaxSzie;

}

public function deQueue()

{

if ($this->head == $this->tail)

return NULL;

$data = $this->data[$this->head];

unset($this->data[$this->head]);

$this->head = (++$this->head) % $this->MaxSzie;

return $data;

}

public function getLength()

{

return ($this->tail - $this->head + $this->MaxSzie) % $this->MaxSzie;

}

}

$queue = new LoopQueue(4);

// var_dump($queue);

$queue->enQueue(1);

$queue->enQueue(2);

$queue->enQueue(3);

$queue->enQueue(4);

// $queue->enQueue(5);

var_dump($queue->getLength());

$queue->deQueue();

$queue->deQueue();

$queue->deQueue();

$queue->deQueue();

$queue->deQueue();

var_dump($queue);