public static function _sub($left_operand, $right_operand, $scale = 50)
{
if (function_exists("bcsub")) {
return bcsub(ilMath::exp2dec($left_operand), ilMath::exp2dec($right_operand), $scale);
} else {
$res = $left_operand - $right_operand;
if (is_numeric($scale)) {
$res = round($res, $scale);
}
return $res;
}
}
/**
* @param $fNumber
* @return string
* function fixes problem which occur when locale ist set to de_DE for example,
* because bc* function expecting strings
*/
private static function bcconv($fNumber)
{
$fNumber = ilMath::exp2dec($fNumber);
$locale_info = localeconv();
if ($locale_info["decimal_point"] != ".") {
$sAppend = '';
$iDecimals = ini_get('precision') - floor(log10(abs($fNumber)));
if (0 > $iDecimals) {
$fNumber *= pow(10, $iDecimals);
$sAppend = str_repeat('0', -$iDecimals);
$iDecimals = 0;
}
return number_format($fNumber, $iDecimals, '.', '') . $sAppend;
}
return $fNumber;
}