生成GUID的算法

类库
<?php
// guid.php
class System {
  function currentTimeMillis() {
    list($usec, $sec) = explode(" ",microtime());
    return $sec.substr($usec, 2, 3);
  }
}

class NetAddress {
  var $name = 'localhost';
  var $ip   = '127.0.0.1';
  function getHost($coumputer_name, $ip) { // static
    $address = new NetAddress();
    $address->name = $coumputer_name;
    $address->ip   = $ip;

    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);
  }
}

class Guid{
  var $valueBeforeMD5;
  var $valueAfterMD5;
  function Guid($computer_name, $ip){
    $this->getGuid($computer_name, $ip);
  }

  function getGuid($coumputer_name, $ip){
    $address = NetAddress::getHost($coumputer_name, $ip);
    $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);
  }
}
?>

调用
<?php
require_once('guid.php');
$computer_name = $_SERVER["SERVER_NAME"];
$ip            = $_SERVER["SERVER_ADDR"];
$guid = new Guid($computer_name, $ip);
print $guid->toString();