Google PageRank 的checksum新算法
在一个国外网站看到的， 先贴出来，有时间的话再仔细分析一下，
并转成jsp语言的，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> .... 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);
?>
