php输出雪花,雪花算法 php Snowflake

/**

* /**

* ID 生成策略

* 毫秒级时间41位+机器ID, 10位+毫秒内序列12位。高位始终为0，表示正数。

* 0 41 51 64

* +-----------+------+------+

* |time |pc |inc |

* +-----------+------+------+

* 前41bits是以微秒为单位的timestamp。

* 接着10bits是事先配置好的机器ID。

* 最后12bits是累加计数器。

* macheine id(10bits)标明最多只能有1024台机器同时产生ID，sequence number(12bits)也标明1台机器1ms中最多产生4096个ID，

*

*/

namespace app\common\lib;

class Snowflake

{

private static $workerId;

private static $maxWorkerId = 1023; //最大的机器节点, 2^10 - 1

private static $sequence = 0;

private static $sequenceMask = 4095; //最大的序列节点, 2^12 - 1

private static $workerIdShift = 12; //机器ID左移位数,63 - 51

private static $timestampLeftShift = 22; //毫秒时间戳左移位数,63 - 41

private static $twepoch = 1288834974657;

private static $lastTimestamp = -1;

/**

* @var self

*/

private static $self = null;

/**

* @return self

*/

public static function getInstance()

{

if (self::$self == null) {

self::$self = new self();

}

return self::$self;

}

public function setWorkId($workId)

{

if ($workId > self::$maxWorkerId || $workId < 0) {

throw new \Exception("worker Id can't be greater than ".self::$maxWorkerId." or less than 0");

}

self::$workerId = $workId;

return self::$self;

}

private function timeGen()

{

//获得当前时间戳

$time = explode(' ', microtime());

$time2 = substr($time[0], 2, 3);

return $time[1] . $time2;

}

private function tilNextMillis($lastTimestamp)

{

$timestamp = $this->timeGen();

while ($timestamp <= $lastTimestamp) {

$timestamp = $this->timeGen();

}

return $timestamp;

}

public function id()

{

$timestamp = $this->timeGen();

//如果存在并发调用，则自增sequence

if (self::$lastTimestamp == $timestamp) {

self::$sequence = (self::$sequence + 1) & self::$sequenceMask;

//如果sequence自增到4095，也就是4096 & 4095 = 0，重新取时间戳

if (self::$sequence == 0) {

$timestamp = $this->tilNextMillis(self::$lastTimestamp);

}

} else {

self::$sequence = 0;

}

if ($timestamp < self::$lastTimestamp) {

throw new \Exception("Clock moved backwards. Refusing to generate id for " . (self::$lastTimestamp - $timestamp) . " milliseconds");

}

self::$lastTimestamp = $timestamp;

if (PHP_INT_SIZE === 4) {

return 0;

}

$nextId = ((sprintf('%.0f', $timestamp) - sprintf(

'%.0f',

self::$twepoch

)) << self::$timestampLeftShift) | (self::$workerId << self::$workerIdShift) | self::$sequence;

return $nextId;

}

}