PHP fingerprint实现

function Fingerprint($str) {
  $kFingerPrintSeed = 19820125;
  return MurmurHash64A($str, $kFingerPrintSeed);
}
 
function getBytes($str) {
    $len = strlen($str);
    $bytes = array();
    for($i=0;$i<$len;$i++) {
        $bytes[] =  ord($str[$i]);
    }
    return $bytes;
}
 
function multi64($x, $y) {
    $result = 0;
    for($i = 0; $i < 64; $i++) {
        $bit = ($x >> $i) & 1;
        if($bit) {
            $result = add64($result, $y << $i);
        }
    }
    return $result;
}
 
function r_shift($num, $bit) {
    if($bit <= 0) return $num;
    if($num > 0) {
        return $num>>$bit;
    } else {
        $num = $num>>1;
        $num = $num & 0x7FFFFFFFFFFFFFFF;
        return r_shift($num, $bit - 1);
    }
}
 
function add64($x,$y){
    $jw = $x & $y;
    $jg = $x ^ $y;
    while($jw)
    {
        $t_a = $jg;
        $t_b = $jw << 1;
        $jw = $t_a & $t_b;
        $jg = $t_a ^ $t_b;
     }
     return $jg;
}
 
function MurmurHash64A($key, $seed) {
  $m = -4132994306676758123;
  $r = 47;
  $len = strlen($key);
 
  $h = $seed ^ (multi64($len, $m));
  $bytes = getBytes($key);
 
  for ($i = 0; $i < ($len / 8) - 1; $i++) {
    $k = 0;
    for ($j = 0; $j < 8; $j++) {
        $k = ($k << 8) | $bytes[$i * 8 + 7 - $j];
    }
    $k = multi64($k, $m);
    $k ^= r_shift($k, $r);
    $k = multi64($k, $m);
    $h ^= $k;
    $h = multi64($h, $m);
  }
 
  $data2_index = $len - $len % 8;
  switch ($len & 7) {
    case 7: $h ^= ($bytes[$data2_index + 6]) << 48;
    case 6: $h ^= ($bytes[$data2_index + 5]) << 40;
    case 5: $h ^= ($bytes[$data2_index + 4]) << 32;
    case 4: $h ^= ($bytes[$data2_index + 3]) << 24;
    case 3: $h ^= ($bytes[$data2_index + 2]) << 16;
    case 2: $h ^= ($bytes[$data2_index + 1]) << 8;
    case 1: $h ^= ($bytes[$data2_index + 0]);
    $h = multi64($h, $m);
  };
 
  $h ^= r_shift($h, $r);
  $h = multi64($h, $m);
  $h ^= r_shift($h, $r);
 
  return $h;

代码见上面：

需要注意的问题是，对PHP来说，没有无符号数，所以会出现负数的问题。

对此可以处理如下

$fp = Fingerprint($model->url);
  if ($fp > 0)
  {
      echo "fp is :".$fp."<br>";
      echo "HEX fp is :".dechex($fp)."<br>";
  } else
  {
      echo "HEX fp is :".dechex($fp)."<br>";
      $new = bcadd('18446744073709551616' ,$fp);
      echo "fp is :".$new.'<br>';
  }

判断计算的fp是正还是负，如果是负数，则通过

bcadd('18446744073709551616' ,$fp) 可以将其转成字符串的表示来正确显示输出。