public static function num2str($num)
{
switch (BigInt::support()) {
case 'gmp':
$str = gmp_strval($num, 16);
$len = strlen($str);
if ($len % 2 == 1) {
$str = '0' . $str;
}
return pack("H*", $str);
case 'big_int':
$str = bi_to_str($num, 16);
$len = strlen($str);
if ($len % 2 == 1) {
$str = '0' . $str;
}
return pack("H*", $str);
case 'bcmath':
bcscale(0);
$str = "";
while (bccomp($num, '0') == 1) {
$str = chr(bcmod($num, '256')) . $str;
$num = bcdiv($num, '256');
}
return $str;
case '':
default:
return BigInt::_num2str($num);
}
}