php GUID生成函数和类

function create_guid() {
    $charid = strtoupper(md5(uniqid(mt_rand(), true)));
    $hyphen = chr(45);// "-"
    $uuid = chr(123)// "{"
    .substr($charid, 0, 8).$hyphen
    .substr($charid, 8, 4).$hyphen
    .substr($charid,12, 4).$hyphen
    .substr($charid,16, 4).$hyphen
    .substr($charid,20,12)
    .chr(125);// "}"
    return $uuid;
}

<?php   
class System   
{   
    function currentTimeMillis()   
    {   
        list($usec, $sec) = explode(" ",microtime());   
        return $sec.substr($usec, 2, 3);   
    }   
}   
class NetAddress   
{   
    var $Name = 'localhost';   
    var $IP = '127.0.0.1';   
    function getLocalHost() // static   
    {   
        $address = new NetAddress();   
        $address->Name = $_ENV["COMPUTERNAME"];   
        $address->IP = $_SERVER["SERVER_ADDR"];   
        return $address;   
    }   
    function toString()   
    {   
        return strtolower($this->Name.'/'.$this->IP);   
    }   
}   
class Random   
{   
    function nextLong()   
    {   
        $tmp = rand(0,1)?'-':'';   
        return $tmp.rand(1000, 9999).rand(1000, 9999).rand(1000, 9999).rand(100, 999).rand(100, 999);   
    }   
}   
// 三段   
// 一段是微秒 一段是地址 一段是随机数   
class Guid   
{   
    var $valueBeforeMD5;   
    var $valueAfterMD5;   
    function Guid()   
    {   
        $this->getGuid();   
    }   
    //   
    function getGuid()   
    {   
        $address = NetAddress::getLocalHost();   
        $this->valueBeforeMD5 = $address->toString().':'.System::currentTimeMillis().':'.Random::nextLong();   
        $this->valueAfterMD5 = md5($this->valueBeforeMD5);   
    }   
    function newGuid()   
    {   
        $Guid = new Guid();   
        return $Guid;   
    }   
    function toString()   
    {   
        $raw = strtoupper($this->valueAfterMD5);   
        return substr($raw,0,8).'-'.substr($raw,8,4).'-'.substr($raw,12,4).'-'.substr($raw,16,4).'-'.substr($raw,20);   
    }   
}

require_once("guid.class.php");   
$Guid = new Guid();   
print $Guid->toString();