[TYPO3] PHP help ! does this code look like it would check a file extensions, and disallow php files or exe files to be attached

[dave typo]

I'm trying to  write php that disallows the posting of specific files,
namely php files and exe files

if someone could look over this snippet and tell me if it works or not that
would be appreciated.

<?php


$filelinks=t3lib_div::_POST('file_name'); // the posting of the file name

$exttypes = "php3,php,exe";                                     // list of
extensions that shouldnt be used
$fileextension = substr($filelinks,0,strpos($filelinks,"."));     //get the
extension after the .
if ($fileextension == $exttypes['php']['php3']['exe']) {         //if the
file extension equals php, php3, or exe
    echo "mime type doesn't work";                                 //if the
extension is php, php3, exe, than echo doesn't work
    }
    if ($fileextension != $extypes['php']['php3']['exe']) {     //if the
file extension doesn't equal php, php3, or exe than
                                                                // store the
file
        $filelinks = $this->storeFile();
        }

?>


I'm not a programmer, and I'm very new at php so im sure there are errors
and stupid logic in my code.

It would be greatly appreciated if anyone here could critique and rip apart
my code.

thank you,

-dave