轻松获取Google PageRank值的源码

　　最近对google的PageRank比较感兴趣，一直想知道如何不用google toolbar来获取pr值。用嗅探工具获得google toolbar发出请求的url为:http://toolbarqueries.google.com//search?client=navclient-auto&ch=64170410360&ie=UTF-8&oe=UTF-8&features=Rank:FVN&q=info:http://www.ugia.cn,其中的关键部分为ch=64170410360,即CheckSum,不知道这个是用的什么算法得出来的。
　　苦苦搜索之后,找到如下代码:
　　转自: http://meese.ath.cx/google via 思路(http://silu.spirezone.com)
/**
This code is released unto the public domain
*/
//header("Content-Type: text/plain; charset=utf-8");
define('GOOGLE_MAGIC', 0xE6359A60);
//unsigned shift right
function zeroFill($a, $b)
{
$z = hexdec(80000000);
if ($z & $a)
{
$a = ($a>>1);
$a &= (~$z);
$a |= 0x40000000;
$a = ($a>>($b-1));
}
else
{
$a = ($a>>$b);
}
return $a;
}
function mix($a,$b,$c) {
$a -= $b; $a -= $c; $a ^= (zeroFill($c,13));
$b -= $c; $b -= $a; $b ^= ($a $c -= $a; $c -= $b; $c ^= (zeroFill($b,13));
$a -= $b; $a -= $c; $a ^= (zeroFill($c,12));
$b -= $c; $b -= $a; $b ^= ($a $c -= $a; $c -= $b; $c ^= (zeroFill($b,5));
$a -= $b; $a -= $c; $a ^= (zeroFill($c,3));
$b -= $c; $b -= $a; $b ^= ($a $c -= $a; $c -= $b; $c ^= (zeroFill($b,15));
return array($a,$b,$c);
}
function GoogleCH($url, $length=null, $init=GOOGLE_MAGIC) {
if(is_null($length)) {
$length = sizeof($url);
}
$a = $b = 0x9E3779B9;
$c = $init;
$k = 0;
$len = $length;
while($len >= 12) {
$a = ($url[$k 0] ($url[$k 1]