public function select()
{
$this->fields = array();
if (func_num_args() == 1) {
$str = str_replace(",", "", func_get_arg(0));
$str = str_replace(";", " ", $str);
$arr = explode(" ", $str);
foreach ($arr as $key => $value) {
if (trim($value) != "") {
array_push($this->fields, $this->parseSelectItem($value));
}
}
} else {
for ($i = 0; $i < func_num_args(); $i++) {
$value = func_get_arg($i);
if (trim($value) != "") {
array_pus($this->fields, $this->parseSelectItem($value));
}
}
}
return $this;
}
function pow_mod($p, $q, $r)
{
// Extract powers of 2 from $q
$factors = array();
$div = $q;
$power_of_two = 0;
while (bccomp($div, "0") == BCCOMP_LARGER) {
$rem = bcmod($div, 2);
$div = bcdiv($div, 2);
if ($rem) {
array_push($factors, $power_of_two);
}
$power_of_two++;
}
// Calculate partial results for each factor, using each partial result as a
// starting point for the next. This depends of the factors of two being
// generated in increasing order.
$partial_results = array();
$part_res = $p;
$idx = 0;
foreach ($factors as $factor) {
while ($idx < $factor) {
$part_res = bcpow($part_res, "2");
$part_res = bcmod($part_res, $r);
$idx++;
}
array_pus($partial_results, $part_res);
}
// Calculate final result
$result = "1";
foreach ($partial_results as $part_res) {
$result = bcmul($result, $part_res);
$result = bcmod($result, $r);
}
return $result;
}
