$x_arr = array();
$m = sizeof($xvalues);
$empty = true;
for ($i = 0; $i < $m; $i += 1) {
$x = $xvalues[$i];
if ($x >= $x_first && $x <= $x_last) {
if ($empty && $x > $x_first) {
array_push($x_arr, $x_first);
}
array_push($x_arr, $x);
$empty = false;
}
}
$xvalues = $x_arr;
if (sizeof($xvalues) > 0) {
$yvalues = $spline->calc_array($xvalues);
} else {
$yvalues = array();
}
//exit('{status:"stuff",data:[],x:'.json_encode($xvalues).',y:'.json_encode($yvalues).',pnt:'.json_encode($points).'}');
} else {
$expr = new Expression();
$expr->parse($expr_str);
$yvalues = $expr->eval_double_array(array(), 'x', $xvalues);
}
$m = sizeof($xvalues);
if ($m == 0) {
exit('{status:"OK?",data:[]}');
}
if ($m != sizeof($yvalues)) {
exit('{status:"error",value:"X-Y mismatch"}');