memcached-分布式一致性哈希算法练习

interface hash{
    function _hash($key);//计算键名对应的32位数值
}
interface distribution{
    function lookup($node);//查看落点
}

class Consistent implements hash,distribution{
    protected $_nodes = array();

    public function _hash($key)
    {
        return sprintf("%u",crc32($key));
    }

    public function lookup($key)
    {
       $point = $this->_hash($key);
        $node = current($this->_nodes);//将最小的key所对应的值付给node
       foreach($this->_nodes as $k => $v){
           if($k>=$point){
                $node = $v;
                break;
           }
       }
       return $node;
    }

    public function addNodes($node)
    {
        //记录服务器节点
        $this->_nodes[$this->_hash($node)] = $node;
        $this->sortNodes();
    }

    public function sortNodes()
    {
        ksort($this->_nodes,SORT_REGULAR);
    }
    public function getNodes()
    {
        return $this->_nodes;
    }
}

$con = new Consistent(); 
$con->addNodes(‘a‘);
$con->addNodes(‘b‘);
$con->addNodes(‘c‘);
echo ‘现有服务器节点有：‘;
print_r($con->getNodes());
echo ‘name的落点为‘.  $con->_hash(‘titleasdas‘) . "<br />";
echo ‘应该写在‘.$con->lookup(‘titleasdas‘)."服务器上";

interface hash{
    function _hash($key);//计算键名对应的32位数值
}
interface distribution{
    function lookup($node);//查看落点
}

class Consistent implements hash,distribution{
    
    protected $_positions = array();
    protected $_nodes = array();
    protected $_mul = 64;
    public function _hash($key)
    {
        return sprintf("%u",crc32($key));
    }

    public function lookup($key)
    {
       $point = $this->_hash($key);
        $node = current($this->_positions);//将最小的key所对应的值付给node
       foreach($this->_positions as $k => $v){
           if($k>=$point){
                $node = $v;
                break;
           }
       }
       return $node;
    }

    public function addPos($node)
    {
        //记录服务器节点
        for($i=0;$i<$this->_mul;$i++){
            $pos = $this->_hash($node.‘-‘.$i);
            $this->_positions[$pos] = $node;
        }
        $this->sortPos();
    }

    public function sortPos()
    {
        ksort($this->_positions,SORT_REGULAR);
    }
    public function getPos()
    {
        return $this->_positions;
    }
}

$con = new Consistent(); 
$con->addPos(‘a‘);
$con->addPos(‘b‘);
$con->addPos(‘c‘);
echo ‘现有服务器节点有：‘;
print_r($con->getPos());
echo ‘name的落点为‘.  $con->_hash(‘titleasdas‘) . "<br />";
echo ‘应该写在‘.$con->lookup(‘titleasdas‘)."服务器上";