php实现的消息队列类

<?php/** * Created by PhpStorm. * User: lin * Date: 2017/6/9 * Time: 11:19 * 实现php共享内存消息队列 */class ShmQueue{    private $maxQSize = 0;//队列最大长度    private $front = 0;//队头指针    private $rear = 0; //队尾指针    private $blockSize = 256;  // 块的大小(byte)    private $memSize = 1280;  // 最大共享内存(byte)    private $shmId = 0;//根据这个id可以操作该共享内存片段    private $filePtr = APP_PATH.'public/shmq.ptr';    private $semId = 0;    public function __construct()    {        $shmkey = ftok(__FILE__, 't');//产生系统id        $this->shmId = shmop_open($shmkey, "c", 0644, $this->memSize );//创建一个内存段        $this->maxQSize = $this->memSize / $this->blockSize;        // 申請一个信号量        $this->semId = sem_get($shmkey, 1);        sem_acquire($this->semId); // 申请进入临界        $this->init();    }    private function init()    {        if ( file_exists($this->filePtr) ){            $contents = file_get_contents($this->filePtr);            $data = explode( '|', $contents );            if ( isset($data[0]) && isset($data[1])){                $this->front = (int)$data[0];                $this->rear  = (int)$data[1];            }        }    }    public function getLength()    {        return (($this->rear - $this->front + $this->memSize) % ($this->memSize) )/$this->blockSize;    }    public function enQueue( $value )    {        if ( $this->ptrInc($this->rear) == $this->front ){ // 队满            return false;        }        //echo $this->front;        $data = $this->encode($value);        shmop_write($this->shmId, $data, $this->rear );        $this->rear = $this->ptrInc($this->rear);        return  $this->decode($data);    }    public function deQueue()    {        if ( $this->front == $this->rear ){ // 队空            throw new Exception(" block size is null!");        }        $value = shmop_read($this->shmId, $this->front, $this->blockSize-1);        $this->front = $this->ptrInc($this->front);        return $this->decode($value);    }    private function ptrInc( $ptr )    {        return ($ptr + $this->blockSize) % ($this->memSize);    }    private function encode( $value )    {        $data = serialize($value) . "__eof";        //echo '';        //echo strlen($data);        //echo '';       // echo $this->blockSize -1;       // echo '';        if ( strlen($data) > $this->blockSize -1 ){            throw new Exception(strlen($data)." is overload block size!");        }        return $data;    }    public function exist($value){//判断队头的数据        $data = shmop_read($this->shmId, $this->front, $this->blockSize-1);        if($value == $this->decode($data)){            return 1;        }        return 0;    }    private function decode( $value )    {        //return $value;        $data = explode("__eof", $value);        return unserialize($data[0]);    }    public function __destruct()    {        //保存队头和队尾指针        $data = $this->front . '|' . $this->rear;        file_put_contents($this->filePtr, $data);        sem_release($this->semId); // 出临界区, 释放信号量    }}

调用:

$shmq = new ShmQueue();入队:$data = 125;$shmq->enQueue($data);出队:$shmq->deQueue();