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Google PageRank值的源代码

<?php
/**
    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 &#038; $a)
        
{
            
$a = ($a>>1);
            
$a &#038;= (~$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< <8);
 
$c -= $a; $c -= $b; $c ^= (zeroFill($b,13));
 
$a -= $b; $a -= $c; $a ^= (zeroFill($c,12));
 
$b -= $c; $b -= $a; $b ^= ($a<<16);
 
$c -= $a; $c -= $b; $c ^= (zeroFill($b,5));
 
$a -= $b; $a -= $c; $a ^= (zeroFill($c,3));
 
$b -= $c; $b -= $a; $b ^= ($a<<10);
 
$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[$k+1]< <8) +($url[$k+2]<<16) +($url[$k+3]<<24));
        
$b += ($url[$k+4] +($url[$k+5]<<8) +($url[$k+6]<<16) +($url[$k+7]<<24));
        
$c += ($url[$k+8] +($url[$k+9]<<8) +($url[$k+10]<<16)+($url[$k+11]<<24));
        
$mix = mix($a,$b,$c);
        
$a = $mix[0]; $b = $mix[1]; $c = $mix[2];
        
$k += 12;
        
$len -= 12;
    
}
 
    
$c += $length;
    
switch($len)              /* all the case statements fall through */
    
{
        
case 11: $c+=($url[$k+10]<<24);
        
case 10: $c+=($url[$k+9]<<16);
        
case 9 : $c+=($url[$k+8]<<8);
          
/* the first byte of c is reserved for the length */
        
case 8 : $b+=($url[$k+7]<<24);
        
case 7 : $b+=($url[$k+6]<<16);
        
case 6 : $b+=($url[$k+5]<<8);
        
case 5 : $b+=($url[$k+4]);
        
case 4 : $a+=($url[$k+3]<<24);
        
case 3 : $a+=($url[$k+2]<<16);
        
case 2 : $a+=($url[$k+1]<<8);
        
case 1 : $a+=($url[$k+0]);
        
/* case 0: nothing left to add */
    
}
    
$mix = mix($a,$b,$c);
    
/*-------------------------------------------- report the result */
    
return $mix[2];
}
 
//converts a string into an array of integers containing the
 
numeric value of the char
 
function strord($string) {
    
for($i=0;$i<strlen($string);$i++) {
        
$result[$i] = ord($string{$i});
    
}
    
return $result;
}
// http://www.example.com/ - Checksum: 6540747202
$url = 'info:'.$_GET['url'];
$ch = GoogleCH(strord($url));
$url='info:'.urlencode($_GET['url']);
echo file_get_contents("http://www.google.com/search?client=
 
navclient-auto&ch=6
$ch&ie=UTF-8&oe=UTF-8&features=Rank&q=$url");
/* use curl send the user angent
$curl = curl_init("
http://www.google.com/search?client=navclient-auto&ch=6$
 
ch&ie=UTF-8&oe=UTF-8&features=Rank&q=$url");
curl_setopt ($curl, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible;
 
GoogleToolbar 2.0.110-big; Windows 2000 5.0)");
curl_exec($curl);
*/

?>

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