<?php interface hash { public function _hash($str); } interface distribution { public function lookup($key); } class Consistent implements hash,distribution { protected $_postion = []; protected $_mul = 64; public function _hash($str){ return sprintf('%u',crc32($str)); } public function lookup($key){ $point = $this->_hash($key); //先取圆环上最小的一个节点 $node = current($this->_postion); foreach($this->_postion as $k=>$v){ if($point <= $k){ $node = $v; break; } } return $node; } //添加节点 public function addNode($node){ for($i = 0;$i<$this->_mul;$i++){ $this->_postion[$this->_hash($node . '-' . $i)] = $node; } $this->_sortPos(); } //删除节点 public function delNode($node){ foreach($this->_postion as $k=>$v){ if($v == $node){ unset($this->_postion[$k]); } } } //排序节点 protected function _sortPos(){ ksort($this->_postion,SORT_REGULAR); } public function printPosition(){ print_r($this->_postion); } } //添加节点 $con = new Consistent(); $con->addNode('a'); $con->addNode('b'); $con->addNode('c'); //删除节点 $con->delNode('b'); echo '所有的服务器如下<br />'; $con->printPosition(); $key = 'title'; echo '当前的键计算的hash落点是' . $con->_hash($key). '<br />'; echo '应该落在'.$con->lookup($key) .'号服务器';