Find Google Page Rank in PHP

<?php

/*
 *
 * @Author: Zuhair Mirza
 * @Implementation Of Google Page Rank in PHP
 * @Date : 17-November-2014
 *
 * Google PageRank (Google PR) is one of the methods Google uses to determine a page's relevance
 * or importance. Important pages receive a higher PageRank and are more likely to appear at the top
 * of the search results. Google PageRank (PR) is a measure from 0 - 10. Google Pagerank is based
 * on backlinks.
 *
 */


$url = 'http://en.wikipedia.org/';

$pr = new GooglePageRank();
echo "$url has Google PageRank: " . $pr->get_google_pagerank($url);



class GooglePageRank {

    public function get_google_pagerank($url) {
       
        $query = "http://toolbarqueries.google.com/tbr?client=navclient-auto&ch=" . $this->CheckHash($this->HashURL($url)) . "&features=Rank&q=info:" . $url . "&num=100&filter=0";
       
        $data = file_get_contents($query);
               
        $pos = strpos($data, "Rank_");
        if ($pos === false) {
           
        } else {
            $pagerank = substr($data, $pos + 9);
            return $pagerank;
        }
    }

    public function StrToNum($Str, $Check, $Magic) {
        $Int32Unit = 4294967296; // 2^32
        $length = strlen($Str);
        for ($i = 0; $i < $length; $i++) {
            $Check *= $Magic;
            if ($Check >= $Int32Unit) {
                $Check = ($Check - $Int32Unit * (int) ($Check / $Int32Unit));
                $Check = ($Check < -2147483648) ? ($Check + $Int32Unit) : $Check;
            }
            $Check += ord($Str{$i});
        }
        return $Check;
    }

    public function HashURL($String) {
        $Check1 = $this->StrToNum($String, 0x1505, 0x21);
        $Check2 = $this->StrToNum($String, 0, 0x1003F);
        $Check1 >>= 2;
        $Check1 = (($Check1 >> 4) & 0x3FFFFC0 ) | ($Check1 & 0x3F);
        $Check1 = (($Check1 >> 4) & 0x3FFC00 ) | ($Check1 & 0x3FF);
        $Check1 = (($Check1 >> 4) & 0x3C000 ) | ($Check1 & 0x3FFF);
        $T1 = (((($Check1 & 0x3C0) << 4) | ($Check1 & 0x3C)) << 2 ) | ($Check2 & 0xF0F );
        $T2 = (((($Check1 & 0xFFFFC000) << 4) | ($Check1 & 0x3C00)) << 0xA) | ($Check2 & 0xF0F0000 );
        return ($T1 | $T2);
    }

    public function CheckHash($Hashnum) {
        $CheckByte = 0;
        $Flag = 0;
        $HashStr = sprintf('%u', $Hashnum);
        $length = strlen($HashStr);
        for ($i = $length - 1; $i >= 0; $i --) {
            $Re = $HashStr{$i};
            if (1 === ($Flag % 2)) {
                $Re += $Re;
                $Re = (int) ($Re / 10) + ($Re % 10);
            }
            $CheckByte += $Re;
            $Flag ++;
        }
        $CheckByte %= 10;
        if (0 !== $CheckByte) {
            $CheckByte = 10 - $CheckByte;
            if (1 === ($Flag % 2)) {
                if (1 === ($CheckByte % 2)) {
                    $CheckByte += 9;
                }
                $CheckByte >>= 1;
            }
        }
        return '7' . $CheckByte . $HashStr;
    }

}

?>