我不希望php move_uploaded_file覆盖现有文件

I have a html page that allows users to submit a file.
Below is my web service for saving submitted files. But I dont want move_uploaded_files to overwrite existing files? What should I do? Thank you

$tmpname = $_FILES["image"]["tmp_name"];
$movedname = "submit-img/" . $_POST["category"] . "/" . $_FILES["image"]["name"];
$prevPage = parse_url($_SERVER['HTTP_REFERER']);

move_uploaded_file($tmpname, $movedname);

Look before you leap:

if (!is_file($movedname)) {
    move_uploaded_file($tmpname, $movedname);
}

I think a more efficient way to handle this situation is checking if file exists, and in this case edit the filename until a match isn't found, then upload the file.

$x=1;
$newfilename=$movedname;

while(is_file($_SERVER['DOCUMENT_ROOT'].$newfilename)){ //actual control

  $newfilename=$movedname;//to prevent creating flower123.jpg at the third iteration, see below

  $fn=explode(".",$newfilename);
  $fp=count($fn)-2;
  $fn[$fp].=$x;
  //here we get the filename before extension (eg. "flower" in fakepath/flower.jpg) and add $x to get "flower1"

  $newfilename=implode(".",$fn);
  //we rebuild our path having now fakepath/flower1.jpg
  $x++;
}

move_uploaded_file($filevar['tmp_name'], $_SERVER['DOCUMENT_ROOT'].$newfilename);

You can check as follows :

if( !is_file($movedname)) {

    move_uploaded_file($tmpname, $movedname);
}

Or suppose if you want to upload the same file for other purposes as well than you can do as follows :

$tmpname = $_FILES["image"]["tmp_name"].''.time();  // use timestamp string to prevent overwrite files

$movedname = "submit-img/" . $_POST["category"] . "/" . $_FILES["image"]["name"];
$prevPage = parse_url($_SERVER['HTTP_REFERER']);

move_uploaded_file($tmpname, $movedname);