PHP library sub table hash algorithm

//Library sub-table algorithm
function calc_hash_db($u, $s = 4) 
{ 
$h = sprintf("%u", crc32($u)); 
$h1 = intval(fmod($h, $s)); 
return $h1; 
} 


for($i=1;$i<100;$i++) 
{ 
echo calc_hash_db($i); 
echo "<br>"; 
} 

function calc_hash_tbl($u, $n = 256, $m = 16) 
{ 
$h = sprintf("%u", crc32($u)); 
$h1 = intval($h / $n); 
$h2 = $h1 % $n; 
$h3 = base_convert($h2, 10, $m); 
$h4 = sprintf("%02s", $h3); 
return $h4; 
}