Use this function in place of pathinfo to make it work with UTF-8 encoded file names too

<?php
function mb_pathinfo($filepath) {
    preg_match('%^(.*?)[\\\\/]*(([^/\\\\]*?)(\.([^\.\\\\/]+?)|))[\\\\/\.]*$%im',$filepath,$m);
    if($m[1]) $ret['dirname']=$m[1];
    if($m[2]) $ret['basename']=$m[2];
    if($m[5]) $ret['extension']=$m[5];
    if($m[3]) $ret['filename']=$m[3];
    return $ret;
}
?>

about the path, there are one thing you should note :
On Windows, both slash (/) and backslash (\) are used as directory separator character. In other environments, it is the forward slash (/).  (this explain is from basename() function part https://www.php.net/manual/en/function.basename.php)
example:
<?php
$path = "https://urvidutta.com /a\b\c\filename.pdf";

echo pathinfo($pdfUrl, PATHINFO_BASENAME);  //get basename
//output
//on window:  result is filename.pdf
//on Linux: result is a\b\c\filename.pdf (that is may not your expect)

//so in order to get same result in different system.  i will do below first.
$path = str_replace($path, '\\', '/'); //convert '\'  to '/'
?>

If a file has more than one 'file extension' (seperated by periods), the last one will be returned.
For example:
<?php
$pathinfo = pathinfo('/dir/test.tar.gz');
echo 'Extension: '.$pathinfo['extension'];
?>
will produce:
Extension: gz

and not tar.gz