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Google PageRank 的checksum新算法
編輯:AJAX詳解     

在一個國外網站看到的, 先貼出來,有時間的話再仔細分析一下,

並轉成JSP語言的,或者ASP的


New PageRank Checksum Algorithm

.]

<?PHP

/*

        Written and contributed by

        Alex Stapleton,

        Andy Doctorow,

        Tarakan,

        Bill Zeller,

        Vijay "Cyberax" Bhatter

        traB

    This code is released into the public domain

*/

//header("Content-Type: text/plain; charset=utf-8");

define('GOOGLE_MAGIC', 0xE6359A60);


function obtainPR($data)

{

     $ret = array();


     $parser = xml_parser_create();

     xml_parser_set_option($parser,XML_OPTION_CASE_FOLDING,0);

     xml_parser_set_option($parser,XML_OPTION_SKIP_WHITE,1);

     xml_parse_into_struct($parser,$data,$values,$tags);

     XML_parser_free($parser);


     $hash_stack = array();


     foreach ($values as $key => $val)

     {

         switch ($val['type'])

         {

           case 'complete':

               array_push($hash_stack, $val['tag']);

               $type = implode($hash_stack, "][");

               if ($type == "RK")

               {

                 $PageRank = $val[value];

               }

               array_pop($hash_stack);

           break;

         }//swhitch

     }//foreach

     

     return $PageRank;

}//obtainPR



//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;

}



// converts an array of 32 bit integers into an array with 8 bit values. Equivalent to (BYTE *)arr32


function c32to8bit($arr32) {

    for($i=0;$i<count($arr32);$i++) {

        for ($bitOrder=$i*4;$bitOrder<=$i*4+3;$bitOrder++) {

            $arr8[$bitOrder]=$arr32[$i]&255;

            $arr32[$i]=zeroFill($arr32[$i], 8);

        }    

    }

    return $arr8;

}



// http://www.example.com/ - Checksum: 6540747202


print("<b>URL .... $url</b>\n");

$url = 'info:' . $url;

$ch = GoogleCH(strord($url));

$url_to_parse = sprintf ("http://toolbarqueries.google.com/search?client=navclient-auto&ch=6%u&IE=UTF-8&oe=UTF-8&q=%s", $ch, $url);

$value = obtainPR(file_get_contents($url_to_parse));

printf("<li> <u>Checksum <2.0.114:</u> ..... 6%u ...... <A href=$url_to_parse>link</A&gt; .... PR = $value\n",$ch); $ch=sprintf("%u", $ch); // new since Toolbar 2.0.114 $ch = ((($ch/7) << 2) | (((int)fmod($ch,13))&7)); $prbuf = array(); $prbuf[0] = $ch; for($i = 1; $i < 20; $i++) { $prbuf[$i] = $prbuf[$i-1]-9; } $ch = GoogleCH(c32to8bit($prbuf), 80); $url_to_parse = sprintf ("http://toolbarqueries.google.com/search?client=navclient-auto&ch=6%u&IE=UTF-8&oe=UTF-8&q=%s", $ch, $url); $value = obtainPR(file_get_contents($url_to_parse)); // printf("<li> <u>Checksum >=2.0.114:</u> ..... 6%u ...... <A href=$url_to_parse>link</A> .... PR = $value\n",$ch); ?>

 

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