Google PageRank Checksum Algorithm

[doctorow]

[cyberax]

WOW !!!

Cheers to Alex

[Alexander Turcic]

doctorow, alex,

you guys don't mind when I bring your findings to the frontpage? It's some interesting work you two came up with!

[cyberax]

Hey.. Alex its Cyberax (Vijay Bhatter)

The site looks good

[alexstapleton]

I'm just setting up a page to demonstrate it. Soon as my remote server wakes up i'll host it on that instead of my home machine. 5 mins or so till im ready.

[doctorow]

Alex, I really like your site. Sure go ahead and post about it!

[alexstapleton]

http://meese.ath.cx/google/

please dont link to this page its hosted on my ADSL line at home. I will make a mirror page on my datacenter server as soon as i can.

[doctorow]

alex, can you provide the source so that we can publish it now?

[doctorow]

Ah just saw it! Thanks!

[alexstapleton]

http://alex.vort-x.net/google/
you may link here.

[cyberax]

Originally Posted by Alexander

doctorow, alex,

you guys don't mind when I bring your findings to the frontpage? It's some interesting work you two came up with!

Seems like I was left out. Anyways...

Thanks to Alex and Doctorow for such a good work

[doctorow]

The Google Checksum Calculator, by Alex Stapleton, Andy Doctorow, Vijay "Cyberax" Bhatter, and a few others.

PHP Code:

<?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 & $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<<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; 
} 
// [url]http://www.example.com/[/url] - Checksum: 6540747202 
$url = 'info:'.$_GET['url']; 
print("url:\t{$_GET['url']}\n"); 
$ch = GoogleCH(strord($url)); 
printf("ch:\t6%u\n",$ch); 
?>

[alexstapleton]

Mmmm messy. Should really of made it prettier. Oh well.

[Alexander Turcic]

cyberax, sorry about that This thread just came to my attention and I didn't read every single post.

[alexstapleton]

http://forums.seochat.com/t12316/s.html
news is spreading fast it seems.