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;
}
}